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Rossi M, Belotti G, Mainardi L, Baroni G, Cerveri P. Feasibility of proton dosimetry overriding planning CT with daily CBCT elaborated through generative artificial intelligence tools. Comput Assist Surg (Abingdon) 2024; 29:2327981. [PMID: 38468391 DOI: 10.1080/24699322.2024.2327981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024] Open
Abstract
Radiotherapy commonly utilizes cone beam computed tomography (CBCT) for patient positioning and treatment monitoring. CBCT is deemed to be secure for patients, making it suitable for the delivery of fractional doses. However, limitations such as a narrow field of view, beam hardening, scattered radiation artifacts, and variability in pixel intensity hinder the direct use of raw CBCT for dose recalculation during treatment. To address this issue, reliable correction techniques are necessary to remove artifacts and remap pixel intensity into Hounsfield Units (HU) values. This study proposes a deep-learning framework for calibrating CBCT images acquired with narrow field of view (FOV) systems and demonstrates its potential use in proton treatment planning updates. Cycle-consistent generative adversarial networks (cGAN) processes raw CBCT to reduce scatter and remap HU. Monte Carlo simulation is used to generate CBCT scans, enabling the possibility to focus solely on the algorithm's ability to reduce artifacts and cupping effects without considering intra-patient longitudinal variability and producing a fair comparison between planning CT (pCT) and calibrated CBCT dosimetry. To showcase the viability of the approach using real-world data, experiments were also conducted using real CBCT. Tests were performed on a publicly available dataset of 40 patients who received ablative radiation therapy for pancreatic cancer. The simulated CBCT calibration led to a difference in proton dosimetry of less than 2%, compared to the planning CT. The potential toxicity effect on the organs at risk decreased from about 50% (uncalibrated) up the 2% (calibrated). The gamma pass rate at 3%/2 mm produced an improvement of about 37% in replicating the prescribed dose before and after calibration (53.78% vs 90.26%). Real data also confirmed this with slightly inferior performances for the same criteria (65.36% vs 87.20%). These results may confirm that generative artificial intelligence brings the use of narrow FOV CBCT scans incrementally closer to clinical translation in proton therapy planning updates.
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Affiliation(s)
- Matteo Rossi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
- Laboratory of Innovation in Sleep Medicine, Istituto Auxologico Italiano, Milan, Italy
| | - Gabriele Belotti
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Luca Mainardi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Guido Baroni
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
- Bioengineering Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy
| | - Pietro Cerveri
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
- Laboratory of Innovation in Sleep Medicine, Istituto Auxologico Italiano, Milan, Italy
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Bouisset N, Nissi J, Laakso I, Reynolds RF, Legros A. Is activation of the vestibular system by electromagnetic induction a possibility in an MRI context? Bioelectromagnetics 2024; 45:171-183. [PMID: 38348647 DOI: 10.1002/bem.22497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 11/21/2023] [Accepted: 12/16/2023] [Indexed: 04/17/2024]
Abstract
In recent years, an increasing number of studies have discussed the mechanisms of vestibular activation in strong magnetic field settings such as occur in a magnetic resonance imaging scanner environment. Amid the different hypotheses, the Lorentz force explanation currently stands out as the most plausible mechanism, as evidenced by activation of the vestibulo-ocular reflex. Other hypotheses have largely been discarded. Nonetheless, both human data and computational modeling suggest that electromagnetic induction could be a valid mechanism which may coexist alongside the Lorentz force. To further investigate the induction hypothesis, we provide, herein, a first of its kind dosimetric analysis to estimate the induced electric fields at the vestibular system and compare them with what galvanic vestibular stimulation would generate. We found that electric fields strengths from induction match galvanic vestibular stimulation strengths generating vestibular responses. This review examines the evidence in support of electromagnetic induction of vestibular responses, and whether movement-induced time-varying magnetic fields should be further considered and investigated.
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Affiliation(s)
- Nicolas Bouisset
- Human Threshold Research Group, Lawson Health Research Institute, London, Ontario, Canada
- School of Kinesiology, Western University, London, Ontario, Canada
| | - Janita Nissi
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Ilkka Laakso
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Raymond F Reynolds
- School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Alexandre Legros
- Human Threshold Research Group, Lawson Health Research Institute, London, Ontario, Canada
- School of Kinesiology, Western University, London, Ontario, Canada
- EuroMov Digital Health in Motion, Univ Montpellier, IMT Mines Ales, Montpellier, France
- Departments of Medical Biophysics and Medical Imaging Western University, London, Ontario, Canada
- Eurostim, Montpellier, France
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Kuhlmann ML, Pojtinger S. Implementation of a new EGSnrc particle source class for computed tomography: validation and uncertainty quantification. Phys Med Biol 2024; 69:095021. [PMID: 38537305 DOI: 10.1088/1361-6560/ad3886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
Objective. Personalized dose monitoring and risk management are of increasing significance with the growing number of computer tomography (CT) examinations. These require high-quality Monte Carlo (MC) simulations that are of the utmost importance for the new developments in personalized CT dosimetry. This work aims to extend the MC framework EGSnrc source code with a new particle source. This, in turn, allows CT-scanner-specific dose and image calculations for any CT scanner. The novel method can be used with all modern EGSnrc user codes, particularly for the simulation of the effective dose based on DICOM images and the calculation of CT images.Approach. The new particle source can be used with input data derived by the user. The input data can be generated by the user based on a previously developed method for the experimental characterization of any CT scanner (doi.org/10.1016/j.ejmp.2015.09.006). Furthermore, the new particle source was benchmarked by air kerma measurements in an ionization chamber at a clinical CT scanner. For this, the simulated angular distribution and attenuation characteristics were compared to measurements to verify the source output free in air. In a second validation step, simulations of air kerma in a homogenous cylindrical and an anthropomorphic thorax phantom were performed and validated against experimentally determined results. A detailed uncertainty evaluation of the simulated air kerma values was developed.Main results. We successfully implemented a new particle source class for the simulation of realistic CT scans. This method can be adapted to any CT scanner. For the attenuation characteristics, there was a maximal deviation of 6.86% between the measurement and the simulation. The mean deviation for all tube voltages was 2.36% (σ= 1.6%). For the phantom measurements and simulations, all the values agreed within 5.0%. The uncertainty evaluation resulted in an uncertainty of 5.5% (k=1).
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Affiliation(s)
- Marie-Luise Kuhlmann
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, D-38116, Germany
- Technische Universität Dortmund, Dortmund, D-44227, Germany
| | - Stefan Pojtinger
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, D-38116, Germany
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Claessens M, Vanreusel V, Gasparini A, Nascimento LDF, Yalvec B, Reniers B, Verellen D. Automated determination of the ion-recombination correction factor (k sat) in ultra-high dose rate electron radiation therapy. Med Phys 2024. [PMID: 38639653 DOI: 10.1002/mp.17085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 03/06/2024] [Accepted: 03/13/2024] [Indexed: 04/20/2024] Open
Abstract
BACKGROUND Plane-parallel ionization chambers are the recommended secondary standard systems for clinical reference dosimetry of electrons. Dosimetry in high dose rate and dose-per-pulse (DPP) is challenging as ionization chambers are subject to ion recombination, especially when dose rate and/or DPP is increased beyond the range of conventional radiotherapy. The lack of universally accepted models for correction of ion recombination in UDHR is still an issue as it is, especially in FLASH-RT research, which is crucial in order to be able to accurately measure the dose for a wide range of dose rates and DPPs. PURPOSE The objective of this study was to show the feasibility of developing an Artificial Intelligence model to predict the ion-recombination factor-ksat for a plane-parallel Advanced Markus ionization chamber for conventional and ultra-high dose rate electron beams based on machine parameters. In addition, the predicted ksat of the AI model was compared with the current applied analytical models for this correction factor. METHODS A total number of 425 measurements was collected with a balanced variety in machine parameter settings. The specific ksat values were determined by dividing the output of the reference dosimeter (optically stimulated luminescence [OSL]) by the output of the AM chamber. Subsequently, a XGBoost regression model was trained, which used the different machine parameters as input features and the corresponding ksat value as output. The prediction accuracy of this regression model was characterized by R2-coefficient of determination, mean absolute error and root mean squared error. In addition, the model was compared with the Two-Voltage (TVA) method and empirical Petersson model for 19 different dose-per-pulse values ranging from conventional to UDHR regimes. The Akiake Information criterion (AIC) was calculated for the three different models. RESULTS The XGBoost regression model reached a R2-score of 0.94 on the independent test set with a MAE of 0.067 and RMSE of 0.106. For the additional 19 random data points, the ksat values predicted by the XGBoost model showed to be in agreement, within the uncertainties, with the ones determined by the Petersson model and better than the TVA method for doses per pulse >3.5 Gy with a maximum deviation from the ground truth of 14.2%, 16.7%, and -36.0%, respectively, for DPP >4 Gy. CONCLUSION The proposed method of using AI for ksat determination displays efficiency. For the investigated DPPs, the ksat values obtained with the XGBoost model were in concurrence with the ones obtained with the current available analytical models within the boundaries of uncertainty, certainly for the DPP characterizing UDHR. But the overall performance of the AI model, taking the number of free parameters into account, lacked efficiency. Future research should optimize the determination of the experimental ksat, and investigate the determination the ksat for DPPs higher than the ones investigated in this study, while also evaluating the prediction of the proposed XGBoost model for UDHR machines of different centers.
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Affiliation(s)
- Michaël Claessens
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
| | - Verdi Vanreusel
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
- Research in Dosimetric Applications (RDA), SCK CEN, Mol, Antwerp, Belgium
| | - Alessia Gasparini
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
| | | | - Burak Yalvec
- NuTeC, CMK, Hasselt University, Hasselt, Belgium
| | | | - Dirk Verellen
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
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Fleta C, Pellegrini G, Godignon P, Rodríguez FG, Paz-Martín J, Kranzer R, Schüller A. State-of-the-art silicon carbide diode dosimeters for ultra-high dose-per-pulse radiation at FLASH radiotherapy. Phys Med Biol 2024; 69:095013. [PMID: 38530300 DOI: 10.1088/1361-6560/ad37eb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 03/26/2024] [Indexed: 03/27/2024]
Abstract
Objective.The successful implementation of FLASH radiotherapy in clinical settings, with typical dose rates >40 Gy s-1, requires accurate real-time dosimetry.Approach.Silicon carbide (SiC) p-n diode dosimeters designed for the stringent requirements of FLASH radiotherapy have been fabricated and characterized in an ultra-high pulse dose rate electron beam. The circular SiC PiN diodes were fabricated at IMB-CNM (CSIC) in 3μm epitaxial 4H-SiC. Their characterization was performed in PTB's ultra-high pulse dose rate reference electron beam. The SiC diode was operated without external bias voltage. The linearity of the diode response was investigated up to doses per pulse (DPP) of 11 Gy and pulse durations ranging from 3 to 0.5μs. Percentage depth dose measurements were performed in ultra-high dose per pulse conditions. The effect of the total accumulated dose of 20 MeV electrons in the SiC diode sensitivity was evaluated. The temperature dependence of the response of the SiC diode was measured in the range 19 °C-38 °C. The temporal response of the diode was compared to the time-resolved beam current during each electron beam pulse. A diamond prototype detector (flashDiamond) and Alanine measurements were used for reference dosimetry.Main results.The SiC diode response was independent both of DPP and of pulse dose rate up to at least 11 Gy per pulse and 4 MGy s-1, respectively, with tolerable deviation for relative dosimetry (<3%). When measuring the percentage depth dose under ultra-high dose rate conditions, the SiC diode performed comparably well to the reference flashDiamond. The sensitivity reduction after 100 kGy accumulated dose was <2%. The SiC diode was able to follow the temporal structure of the 20 MeV electron beam even for irregular pulse estructures. The measured temperature coefficient was (-0.079 ± 0.005)%/°C.Significance.The results of this study demonstrate for the first time the suitability of silicon carbide diodes for relative dosimetry in ultra-high dose rate pulsed electron beams up to a DPP of 11 Gy per pulse.
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Affiliation(s)
- Celeste Fleta
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain
| | - Giulio Pellegrini
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain
| | - Philippe Godignon
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain
| | - Faustino Gómez Rodríguez
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
- Laboratorio de Radiofísica, RIAIDT, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - José Paz-Martín
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Rafael Kranzer
- PTW-Freiburg (R&D), Freiburg 79115, Germany
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, 26121, Germany
| | - Andreas Schüller
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
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Moraitis A, Jentzen W, Costa PF, Kersting D, Himmen S, Coelho M, Meckel M, van Echteld CJA, Fendler WP, Herrmann K, Sraieb M. Safety and Efficacy of Para-Aminohippurate Coinfusion for Renal Protection During Peptide Receptor Radiotherapy in Patients with Neuroendocrine Tumors. J Nucl Med 2024:jnumed.123.266619. [PMID: 38637142 DOI: 10.2967/jnumed.123.266619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 03/04/2024] [Indexed: 04/20/2024] Open
Abstract
Para-aminohippurate, also known as p-aminohippuric acid (PAH), is used clinically to measure effective renal plasma flow. Preclinically, it was shown to reduce 177Lu-DOTATOC uptake in the kidneys while improving bioavailability compared with amino acid (AA) coinfusion. We report the safety and efficacy of PAH coinfusion during peptide receptor radiotherapy in patients with neuroendocrine tumors. Methods: Twelve patients with metastatic or unresectable gastroenteropancreatic neuroendocrine tumors received 177Lu-DOTATOC in 33 treatment cycles. Either 8 g of PAH or a mixture of 25 g of arginine and 25 g of lysine were coinfused. Safety was assessed by monitoring laboratory data, including hematologic and renal data, as well as electrolytes obtained before and 24 h after treatment. For radiation dosimetry, whole-body scans were performed at 1, 24, and 48 h and a SPECT/CT scan was performed at 48 h, along with blood sampling at 5 min and 0.5, 2, 4, 24, and 48 h after administration. Absorbed dose estimations for the kidneys and bone marrow were performed according to the MIRD concept. Results: In 15 treatment cycles, PAH was coinfused. No changes in mean creatinine level, glomerular filtration rate, and serum electrolytes were observed before or 24 h after treatment when using PAH protection (P ≥ 0.20), whereas serum chloride and serum phosphate increased significantly under AA (both P < 0.01). Kidney-absorbed dose coefficients were 0.60 ± 0.14 Gy/GBq with PAH and 0.53 ± 0.16 Gy/GBq with AA. Based on extrapolated cumulative kidney-absorbed doses for 4 cycles, 1 patient with PAH protection and 1 patient with AA protection in our patient group would exceed the 23-Gy conservative threshold. The bone marrow-absorbed dose coefficient was 0.012 ± 0.004 Gy/GBq with PAH and 0.012 ± 0.003 Gy/GBq with AA. Conclusion: PAH is a promising alternative to AA for renal protection during peptide receptor radiotherapy. Further research is required to systematically investigate the safety profile and radiation dosimetry at varying PAH plasma concentrations.
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Affiliation(s)
- Alexandros Moraitis
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany;
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Walter Jentzen
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - David Kersting
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Stephan Himmen
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Marta Coelho
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Marian Meckel
- ITM Isotope Technologies Munich SE, Garching/Munich, Germany; and
| | | | - Wolfgang P Fendler
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium, Partner Site University Hospital Essen, Essen, Germany
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Leube J, Gustafsson J, Lassmann M, Salas-Ramirez M, Tran-Gia J. A Deep-Learning-Based Partial-Volume Correction Method for Quantitative 177Lu SPECT/CT Imaging. J Nucl Med 2024:jnumed.123.266889. [PMID: 38637141 DOI: 10.2967/jnumed.123.266889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 03/15/2024] [Indexed: 04/20/2024] Open
Abstract
With the development of new radiopharmaceutical therapies, quantitative SPECT/CT has progressively emerged as a crucial tool for dosimetry. One major obstacle of SPECT is its poor resolution, which results in blurring of the activity distribution. Especially for small objects, this so-called partial-volume effect limits the accuracy of activity quantification. Numerous methods for partial-volume correction (PVC) have been proposed, but most methods have the disadvantage of assuming a spatially invariant resolution of the imaging system, which does not hold for SPECT. Furthermore, most methods require a segmentation based on anatomic information. Methods: We introduce DL-PVC, a methodology for PVC of 177Lu SPECT/CT imaging using deep learning (DL). Training was based on a dataset of 10,000 random activity distributions placed in extended cardiac-torso body phantoms. Realistic SPECT acquisitions were created using the SIMIND Monte Carlo simulation program. SPECT reconstructions without and with resolution modeling were performed using the CASToR and STIR reconstruction software, respectively. The pairs of ground-truth activity distributions and simulated SPECT images were used for training various U-Nets. Quantitative analysis of the performance of these U-Nets was based on metrics such as the structural similarity index measure or normalized root-mean-square error, but also on volume activity accuracy, a new metric that describes the fraction of voxels in which the determined activity concentration deviates from the true activity concentration by less than a certain margin. On the basis of this analysis, the optimal parameters for normalization, input size, and network architecture were identified. Results: Our simulation-based analysis revealed that DL-PVC (0.95/7.8%/35.8% for structural similarity index measure/normalized root-mean-square error/volume activity accuracy) outperforms SPECT without PVC (0.89/10.4%/12.1%) and after iterative Yang PVC (0.94/8.6%/15.1%). Additionally, we validated DL-PVC on 177Lu SPECT/CT measurements of 3-dimensionally printed phantoms of different geometries. Although DL-PVC showed activity recovery similar to that of the iterative Yang method, no segmentation was required. In addition, DL-PVC was able to correct other image artifacts such as Gibbs ringing, making it clearly superior at the voxel level. Conclusion: In this work, we demonstrate the added value of DL-PVC for quantitative 177Lu SPECT/CT. Our analysis validates the functionality of DL-PVC and paves the way for future deployment on clinical image data.
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Affiliation(s)
- Julian Leube
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany; and
| | | | - Michael Lassmann
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany; and
| | - Maikol Salas-Ramirez
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany; and
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany; and
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Giannini N, Gadducci G, Fuentes T, Gonnelli A, Di Martino F, Puccini P, Naso M, Pasqualetti F, Capaccioli S, Paiar F. Electron FLASH radiotherapy in vivo studies. A systematic review. Front Oncol 2024; 14:1373453. [PMID: 38655137 PMCID: PMC11035725 DOI: 10.3389/fonc.2024.1373453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 03/15/2024] [Indexed: 04/26/2024] Open
Abstract
FLASH-radiotherapy delivers a radiation beam a thousand times faster compared to conventional radiotherapy, reducing radiation damage in healthy tissues with an equivalent tumor response. Although not completely understood, this radiobiological phenomenon has been proved in several animal models with a spectrum of all kinds of particles currently used in contemporary radiotherapy, especially electrons. However, all the research teams have performed FLASH preclinical studies using industrial linear accelerator or LINAC commonly employed in conventional radiotherapy and modified for the delivery of ultra-high-dose-rate (UHDRs). Unfortunately, the delivering and measuring of UHDR beams have been proved not to be completely reliable with such devices. Concerns arise regarding the accuracy of beam monitoring and dosimetry systems. Additionally, this LINAC totally lacks an integrated and dedicated Treatment Planning System (TPS) able to evaluate the internal dose distribution in the case of in vivo experiments. Finally, these devices cannot modify dose-time parameters of the beam relevant to the flash effect, such as average dose rate; dose per pulse; and instantaneous dose rate. This aspect also precludes the exploration of the quantitative relationship with biological phenomena. The dependence on these parameters need to be further investigated. A promising advancement is represented by a new generation of electron LINAC that has successfully overcome some of these technological challenges. In this review, we aim to provide a comprehensive summary of the existing literature on in vivo experiments using electron FLASH radiotherapy and explore the promising clinical perspectives associated with this technology.
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Affiliation(s)
- Noemi Giannini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Tuscany, Italy
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
| | - Giovanni Gadducci
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Tuscany, Italy
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
| | - Taiusha Fuentes
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Tuscany, Italy
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
| | - Alessandra Gonnelli
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Tuscany, Italy
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
| | - Fabio Di Martino
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
- Unit of Medical Physics, Azienda Ospedaliero-Universitaria Pisana, Pisa, Tuscany, Italy
- National Institute of Nuclear Physics (INFN)-section of Pisa, Pisa, Tuscany, Italy
| | - Paola Puccini
- Department of Radiation Oncology, Azienda Ospedaliera Universitaria Pisana, University of Pisa, Pisa, Tuscany, Italy
| | - Monica Naso
- Department of Radiation Oncology, Azienda Ospedaliera Universitaria Pisana, University of Pisa, Pisa, Tuscany, Italy
| | - Francesco Pasqualetti
- Department of Radiation Oncology, Azienda Ospedaliera Universitaria Pisana, University of Pisa, Pisa, Tuscany, Italy
| | - Simone Capaccioli
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
- Department of Physics, University of Pisa, Pisa, Tuscany, Italy
| | - Fabiola Paiar
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Tuscany, Italy
- Centro Pisano Multidisciplinare Sulla Ricerca e Implementazione Clinica Della Flash Radiotherapy (CPFR), University of Pisa, Pisa, Italy
- Department of Radiation Oncology, Azienda Ospedaliera Universitaria Pisana, University of Pisa, Pisa, Tuscany, Italy
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Khreish F, Schaefer-Schuler A, Roth L, Burgard C, Rosar F, Ezziddin S. Concomitant lithium increases radioiodine uptake and absorbed doses per administered activity in graves' disease: comparison of conventional versus lithium-augmented radioiodine therapy. Front Med (Lausanne) 2024; 11:1382024. [PMID: 38646563 PMCID: PMC11026544 DOI: 10.3389/fmed.2024.1382024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 03/21/2024] [Indexed: 04/23/2024] Open
Abstract
BackgroundLithium inhibits iodine and thyroid hormone release from thyroid cells, possibly increasing radioiodine retention and anti-hyperthyroid efficacy when given adjunctively to radioiodine therapy (RAI) of Graves’ disease (GD). However, the literature contains limited dosimetric data regarding the influence of concomitant lithium in this setting.MethodsWe retrospectively compared dosimetric variables in patients undergoing RAI with/without adjunctive lithium (n = 52 each). We assessed two low-dose, short-duration oral lithium carbonate regimens, 450 mg/d (n = 22) or 900 mg/d (n = 30), for a mean of 4.7 ± 1.4 d starting upon RAI administration. Patients underwent diagnostic testing to measure thyroidal radioiodine uptake (RAIU) 24 h ± 2 h after ingesting up to 5 MBq radioiodine, receiving individualized RAI activities 24 h later. Using ≥3 RAIU daily measurements starting 24 h post-RAI, researchers were able to determine the effective radioiodine half-life and absorbed dose to the thyroid; we also calculated the absorbed dose per administered activity concentration within that organ. Rates of GD cure, defined as reaching euthyroidism or hypothyroidism post-RAI, were evaluated in patients with ~6 months or longer post-RAI follow-up.ResultsThe lithium dosage subgroups had similar dosimetric values and thus are considered together. Lithium patients and controls had similar average “diagnostic” RAIU (51.1% ± 15.7% vs. 50.6% ± 13.8%, p = 0.820), but the former had significantly higher RAIU post-RAI (56.3% ± 13.5% vs. 49.1% ± 13.5%, p = 0.002), reflecting significantly greater change in the former (+16.2% ± 30.4% vs. -1.8% ± 16.1%, p = 0.001). Radioiodine effective half-life was non-significantly longer in lithium patients (5.43 ± 1.50 d vs. 5.08 ± 1.16 d, p = 0.192). The mean RAI administered activity was 27% less in lithium patients (677 ± 294 MBq vs. 930 ± 433 MBq, p = 0.001), but GD cure rates were similar (83% [39/47] vs. 82% [33/40], p = 0.954), possibly due to the significantly higher thyroid dose in the lithium patients, especially in thyroid gland with a volume ≤ 20 mL (1.04 ± 0.44 Gy/MBq vs. 0.76 ± 0.30 Gy/MBq, p = 0.020). Day 3 serum lithium concentrations were low (450 mg/d: 0.26 ± 0.12 mmol/L, 900 mg/d: 0.50 ± 0.18 mmol/L); no lithium toxicity was noted.ConclusionLithium augmentation may increase the RAIU and thyroid absorbed dose, permitting potentially decreased RAI activities without sacrificing efficacy. Our observations should be confirmed in a prospective, randomized trial.
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Affiliation(s)
- Fadi Khreish
- Department of Nuclear Medicine, Saarland University Hospital, Homburg, Germany
- Department of Nuclear Medicine, Campus-Fulda, University of Marburg, Fulda, Germany
| | | | - Leonie Roth
- Department of Nuclear Medicine, Saarland University Hospital, Homburg, Germany
| | - Caroline Burgard
- Department of Nuclear Medicine, Saarland University Hospital, Homburg, Germany
| | - Florian Rosar
- Department of Nuclear Medicine, Saarland University Hospital, Homburg, Germany
| | - Samer Ezziddin
- Department of Nuclear Medicine, Saarland University Hospital, Homburg, Germany
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10
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Daisaki H, Kubota C, Ishikawa K, Sato M, Yasumoto Y, Fukai S, Sakashita T. [Validation of Quantitative Accuracy and Variability in 177Lu Imaging Using Monte Carlo Simulation]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2024:2024-1451. [PMID: 38569841 DOI: 10.6009/jjrt.2024-1451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
PURPOSE To predict side effects and optimize injection doses in the dosimetry of 177Lu imaging, highly accurate quantitative SPECT images are required. Monte Carlo simulations were performed to verify the accuracy and variability of quantitative values for 177Lu imaging under various imaging conditions. METHOD SPECT data of NEMA body phantom were assumed to simulate intrahepatic tumors 6 h after administration of 7.4 GBq of 177Lu-Dotatate. SPECT data were acquired using the SIMIND program with different combinations of collimators and energy windows. For variability evaluation, 30 SPECT images with Poisson noise were generated for each acquisition time. The relative error was evaluated for accuracy evaluation, and the coefficient of variation was estimated for variability evaluation. RESULTS The accuracy of BG quantification was less than 10% relative error. The accuracy of hot sphere quantification was highest with the combination of MEGP and an energy window of 208 keV±10%. However, the accuracy of hot sphere quantification decreased significantly with decreasing hot sphere diameter. Variability varied with imaging conditions and improved with longer acquisition time. CONCLUSION Monte Carlo simulations revealed the accuracy and variability of quantitative values for each SPECT imaging condition for 177Lu imaging.
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Affiliation(s)
- Hiromitsu Daisaki
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Chihiro Kubota
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Kazuma Ishikawa
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Mitsuru Sato
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | | | - Shohei Fukai
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Tetsuya Sakashita
- Department of Quantum-Applied Biosciences, Takasaki Institute for Advanced Quantum Science, National Institutes for Quantum Science and Technology
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11
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Bastiaannet R, Lin M, Frey EC, de Jong HW. Intraprocedural C-arm dual-phase cone-beam enhancement patterns correlate with tumor absorbed dose after radioembolization. Med Phys 2024; 51:3045-3052. [PMID: 38064591 PMCID: PMC10994751 DOI: 10.1002/mp.16882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND Recent studies have shown a clear relationship between absorbed dose and tumor response to treatment after hepatic radioembolization. These findings help to create more personalized treatment planning and dosimetry. However, crucial to this goal is the ability to predict the dose distribution prior to treatment. The microsphere distribution is ultimately determined by (i) the hepatic vasculature and the resulting blood flow dynamics and (ii) the catheter position. PURPOSE To show that pretreatment, intra-procedural imaging of blood flow patterns, as quantified by catheter-directed intra-arterial contrast enhancement, correlate with posttreatment microsphere accumulation and, consequently, absorbed dose. MATERIALS AND METHODS Patients who participated in a clinical trial (NCT01177007) and for whom both a pretreatment dual-phase contrast-enhanced cone-beam CT (CBCT) and a posttreatment 90Y PET/CT scan were available were included in this retrospective study. Tumors and perfused volumes were manually delineated on the CBCT by an experienced radiologist. The mean, sum, and standard deviation of the voxels in each volume were recorded. The delineations were transferred to the PET-based absorbed dose maps by coregistration of the corresponding CTs. Linear multiple regression was used to correlate pretreatment CBCT enhancement to posttreatment 90Y PET/CT-based absorbed dose in each region. Leave-one-out cross-validation and Bland-Altman analyses were performed on the predicted versus measured absorbed doses. RESULTS Nine patients, with a total of 23 tumors were included. All presented with hepatocellular carcinoma (HCC). Visually, all patients had a clear correspondence between CBCT enhancement and absorbed dose. The correlation between CBCT enhancement and posttherapy absorbed tumor dose based was strong (R2 = 0.91), and moderate for the non-tumor liver tissue (R2 = 0.61). Limits of agreement were approximately ±55 Gray for tumor tissue. CONCLUSION There is a linear relationship between pretreatment blood dynamics in HCC tumors and posttreatment absorbed dose, which, if shown to be generalizable, allows for pretreatment tumor absorbed dose prediction.
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Affiliation(s)
- Remco Bastiaannet
- The Russell H Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - MingDe Lin
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States
| | - Eric C. Frey
- The Russell H Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Hugo W.A.M. de Jong
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
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Gibbons T, Perkins A, Barnett J. Safety, biodistribution and radiation dosimetry of the Arg-Gly-Asp peptide 99m Tc-maraciclatide in healthy volunteers. Nucl Med Commun 2024; 45:295-303. [PMID: 38312052 PMCID: PMC10916747 DOI: 10.1097/mnm.0000000000001814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/19/2023] [Indexed: 02/06/2024]
Abstract
BACKGROUND 99m Tc-Maraciclatide is a radiolabelled RGD (Arg-Gly-Asp) peptide that binds with high affinity to α v β 3 and α v β 5 integrins, common receptors upregulated in disease states involving angiogenesis and inflammation. As such, it holds promise as a novel diagnostic imaging agent for a range of pathological conditions. The present study provides the safety, biodistribution and radiation dosimetry of 99m Tc-maraciclatide in healthy volunteers. METHODS A phase 1, randomised, placebo-controlled study assessed the safety, biodistribution and radiation dosimetry of 99m Tc-maraciclatide in healthy volunteers. Participants were randomised into three groups receiving 99m Tc-maraciclatide and three chemical amounts of maraciclatide in an escalating dose protocol. Eight participants in each group received the required amount of maraciclatide via intravenous injection, with the remaining two receiving a placebo. Biodistribution was assessed by acquiring scintigraphic images at time points up to 24 h after a bolus injection of 99m Tc-maraciclatide. 99m Tc-maraciclatide activity in plasma and urine was measured up to 7 days post-administration. RESULTS 99m Tc-maraciclatide was safe and well tolerated, with no serious adverse events reported. Initial uptakes of 99m Tc were highest in the gastrointestinal tract (20%), liver (15%), and lungs (9%). Similarly, the regions with the highest normalised cumulated activities were the contents of the urinary bladder and voided urine (3.4 ± 0.4 MBq*h/MBq), the combined walls of the small intestine and upper and lower large intestine (0.9 ± 0.2 MBq*h/MBq), liver (0.8 ± 0.2 MBq*h/MBq), lung (0.4 ± 0.1 MBq*h/MBq). The main route of 99m Tc excretion was renal (55%), with a systemic urinary clearance of approximately 6.7 ml/min/kg. The pharmacokinetic analysis gave a mean apparent terminal elimination half-life of the unlabelled molecular maraciclatide of approximately 1 h, independent of dose. The mean ED per unit injected activity was 7.8 ± 0.8 µSv/MBq. CONCLUSION 99m Tc-maraciclatide is a safe radiopharmaceutical formulation with a dosimetry profile similar to other 99m Tc-based imaging agents.
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Affiliation(s)
- Tatjana Gibbons
- Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital, Oxford
| | - Alan Perkins
- Radiological Sciences, School of Medicine, University of Nottingham, Nottingham and
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13
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Njotu FN, Ketchemen JP, Tikum AF, Babeker H, Gray BD, Pak KY, Uppalapati M, Fonge H. Efficacy of [ 67Cu]Cu-EB-TATE Theranostic Against Somatostatin Receptor Subtype-2-Positive Neuroendocrine Tumors. J Nucl Med 2024; 65:533-539. [PMID: 38485273 DOI: 10.2967/jnumed.123.265997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 01/29/2024] [Indexed: 04/04/2024] Open
Abstract
β--emitting 177Lu-octreotate is an approved somatostatin receptor subtype 2 (SSTR2)-directed peptide receptor radionuclide therapy for the treatment of gastroenteropancreatic neuroendocrine tumors (NETs). However,177Lu-octreotate has fast pharmacokinetics, requiring up to 4 treatment doses. Moreover, 177Lu is less than ideal for theranostics because of the low branching ratio of its γ-emissions, which limits its SPECT imaging capability. Compared with 177Lu, 67Cu has better decay properties for use as a theranostic. Here, we report the preclinical evaluation of a long-lived somatostatin analog, [67Cu]Cu-DOTA-Evans blue-TATE (EB-TATE), against SSTR2-positive NETs. Methods: The in vitro cytotoxicity of [67Cu]Cu-EB-TATE was investigated on 2-dimensional cells and 3-dimensional spheroids. In vivo pharmacokinetics and dosimetry were studied in healthy BALB/c mice, whereas ex vivo biodistribution, micro-SPECT/CT imaging, and therapy studies were done on athymic nude mice bearing QGP1.SSTR2 and BON1.SSTR2 xenografts. Therapeutic efficacy was compared with [177Lu]Lu-EB-TATE. Results: Projected human effective doses of [67Cu]Cu-EB-TATE for male (0.066 mSv/MBq) and female (0.085 mSv/MBq) patients are tolerable. In vivo micro-SPECT/CT imaging of SSTR2-positive xenografts with [67Cu]Cu-EB-TATE showed tumor-specific uptake and prolonged accumulation. Biodistribution showed tumor accumulation, with concurrent clearance from major organs over a period of 72 h. [67Cu]Cu-EB-TATE was more effective (60%) at eliminating tumors that were smaller than 50 mm3 within the first 15 d of therapy than was [177Lu]Lu-EB-TATE (20%) after treatment with 2 doses of 15 MBq administered 10 d apart. Mean survival of [67Cu]Cu-EB-TATE-treated groups was 90 d and more than 90 d, whereas that of [177Lu]Lu-EB-TATE was more than 90 d and 89 d against vehicle control groups (26 d and 53 d), for QGP1.SSTR2 and BON1.SSTR2 xenografts, respectively. Conclusion: [67Cu]Cu-EB-TATE exhibited high SSTR2-positive NET uptake and retention, with favorable dosimetry and SPECT/CT imaging capabilities. The antitumor efficacy of [67Cu]Cu-EB-TATE is comparable to that of [177Lu]Lu-EB-TATE, with [67Cu]Cu-EB-TATE being slightly more effective than [177Lu]Lu-EB-TATE for complete remission of small tumors. [67Cu]Cu-EB-TATE therefore warrants clinical development.
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Affiliation(s)
- Fabrice Ngoh Njotu
- Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Jessica Pougoue Ketchemen
- Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Anjong Florence Tikum
- Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hanan Babeker
- Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Brian D Gray
- Molecular Targeting Technologies, Inc., West Chester, Pennsylvania; and
| | - Koon Y Pak
- Molecular Targeting Technologies, Inc., West Chester, Pennsylvania; and
| | - Maruti Uppalapati
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada;
| | - Humphrey Fonge
- Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada;
- Department of Medical Imaging, Royal University Hospital Saskatoon, Saskatoon, Saskatchewan, Canada
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14
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Lizonova D, Trivanovic U, Demokritou P, Kelesidis GA. Dispersion and Dosimetric Challenges of Hydrophobic Carbon-Based Nanoparticles in In Vitro Cellular Studies. Nanomaterials (Basel) 2024; 14:589. [PMID: 38607123 PMCID: PMC11013865 DOI: 10.3390/nano14070589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/18/2024] [Accepted: 03/21/2024] [Indexed: 04/13/2024]
Abstract
Methodologies across the dispersion preparation, characterization, and cellular dosimetry of hydrophilic nanoparticles (NPs) have been developed and used extensively in the field of nanotoxicology. However, hydrophobic NPs pose a challenge for dispersion in aqueous culture media using conventional methods that include sonication followed by mixing in the culture medium of interest and cellular dosimetry. In this study, a robust methodology for the preparation of stable dispersions of hydrophobic NPs for cellular studies is developed by introducing continuous energy over time via stirring in the culture medium followed by dispersion characterization and cellular dosimetry. The stirring energy and the presence of proteins in the culture medium result in the formation of a protein corona around the NPs, stabilizing their dispersion, which can be used for in vitro cellular studies. The identification of the optimal stirring time is crucial for achieving dispersion and stability. This is assessed through a comprehensive stability testing protocol employing dynamic light scattering to evaluate the particle size distribution stability and polydispersity. Additionally, the effective density of the NPs is obtained for the stable NP dispersions using the volumetric centrifugation method, while cellular dosimetry calculations are done using available cellular computational modeling, mirroring approaches used for hydrophilic NPs. The robustness of the proposed dispersion approach is showcased using a highly hydrophobic NP model (black carbon NPs) and two culture media, RPMI medium and SABM, that are widely used in cellular studies. The proposed approach for the dispersion of hydrophobic NPs results in stable dispersions in both culture media used here. The NP effective density of 1.03-1.07 g/cm3 measured here for black carbon NPs is close to the culture media density, resulting in slow deposition on the cells over time. So, the present methodology for dispersion and dosimetry of hydrophobic NPs is essential for the design of dose-response studies and overcoming the challenges imposed by slow particle deposition.
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Affiliation(s)
- Denisa Lizonova
- Nanoscience and Advanced Materials Center (NAMC), Environmental and Occupational Health Science Institute, School of Public Health, Rutgers University, 170 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Una Trivanovic
- Particle Technology Laboratory, Institute of Energy and Process Engineering, Department of Mechanical and Process Engineering, ETH Zürich, Sonneggstrasse 3, CH-8092 Zürich, Switzerland
| | - Philip Demokritou
- Nanoscience and Advanced Materials Center (NAMC), Environmental and Occupational Health Science Institute, School of Public Health, Rutgers University, 170 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Georgios A. Kelesidis
- Nanoscience and Advanced Materials Center (NAMC), Environmental and Occupational Health Science Institute, School of Public Health, Rutgers University, 170 Frelinghuysen Road, Piscataway, NJ 08854, USA
- Particle Technology Laboratory, Institute of Energy and Process Engineering, Department of Mechanical and Process Engineering, ETH Zürich, Sonneggstrasse 3, CH-8092 Zürich, Switzerland
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Frencken AL, Richtsmeier D, Leonard RL, Williams AG, Johnson CE, Johnson JA, Blasiak B, Orlef A, Skorupa A, Sokół M, Tomanek B, Beckham W, Bazalova-Carter M, van Veggel FCJM. X-ray-Sensitive Doped CaF 2-Based MRI Contrast Agents for Local Radiation Dose Measurement. ACS Appl Mater Interfaces 2024; 16:13453-13465. [PMID: 38445594 DOI: 10.1021/acsami.3c16336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Ionizing radiation has become widely used in medicine, with application in diagnostic techniques, such as computed tomography (CT) and radiation therapy (RT), where X-rays are used to diagnose and treat tumors. The X-rays used in CT and, in particular, in RT can have harmful side effects; hence, an accurate determination of the delivered radiation dose is of utmost importance to minimize any damage to healthy tissues. For this, medical specialists mostly rely on theoretical predictions of the delivered dose or external measurements of the dose. To extend the practical use of ionizing radiation-based medical techniques, such as magnetic resonance imaging (MRI)-guided RT, a more precise measurement of the internal radiation dose internally is required. In this work, a novel approach is presented to measure dose in liquids for potential future in vivo applications. The strategy relies on MRI contrast agents (CAs) that provide a dose-sensitive signal. The demonstrated materials are (citrate-capped) CaF2 nanoparticles (NPs) doped with Eu3+ or Fe2+/Fe3+ ions. Free electrons generated by ionizing radiation allow the reduction of Eu3+, which produces a very small contrast in MRI, to Eu2+, which induces a strong contrast. Oxidative species generated by high-energy X-rays can be measured indirectly using Fe2+ because it oxidizes to Fe3+, increasing the contrast in MRI. Notably, in the results, a strong increase in the proton relaxation rates is observed for the Eu3+-doped NPs at 40 kV. At 6 MV, a significant increase in proton relaxation rates is observed using CaF2 NPs doped with Fe2+/Fe3+ after irradiation. The presented concept shows great promise for use in the clinic to measure in vivo local ionizing radiation dose, as these CAs can be intravenously injected in a saline solution.
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Affiliation(s)
- Adriaan L Frencken
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Devon Richtsmeier
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - R Lee Leonard
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Aleia G Williams
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Charles E Johnson
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Jacqueline A Johnson
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Barbara Blasiak
- Experimental Imaging Centre, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow 31-342, Poland
| | - Andrzej Orlef
- Department of Medical Physics, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-102 Gliwice, Poland
| | - Agnieszka Skorupa
- Department of Medical Physics, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-102 Gliwice, Poland
| | - Maria Sokół
- Department of Medical Physics, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-102 Gliwice, Poland
| | - Boguslaw Tomanek
- Experimental Imaging Centre, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow 31-342, Poland
- Oncology Department, University of Alberta, 8303-112 Street NW, Edmonton, Alberta T6G 2T4, Canada
| | - Wayne Beckham
- BC Cancer, Royal Jubilee Hospital, Victoria, British Columbia V8R 6 V5, Canada
| | - Magdalena Bazalova-Carter
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Frank C J M van Veggel
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
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Furukawa M, Isobe R, Ono S, Gonai Y, Shindo R, Yamamoto K, Inaba Y, Chida K. [Temperature Dependence of Scintillation Survey Meter with and without Temperature Compensation Function]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2024; 80:279-286. [PMID: 38311432 DOI: 10.6009/jjrt.2024-1382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
PURPOSE The objective of this study was to compare the temperature dependence of a scintillation survey meter with and without the temperature compensation function. Investigation of temperature dependence is important to make precise measurements in various environments. METHOD The experiment was conducted using the NaI (Tl) scintillation survey meter with the temperature compensation function (TCS-1172) and the NaI (Tl) and CsI (Tl) scintillation survey meters without the temperature compensation function (TCS-171, PDR-111). In all, 1 cm dose equivalent rate (µSv/h) was measured by changing the room temperature from 10 to 40 degree Celsius. RESULT The results showed that the scintillation survey meter with the temperature compensation function had almost no change in the measured values with changes in room temperature, whereas the 1 cm dose equivalent rate of the scintillation survey meter without the temperature compensation function changed by a maximum of -7.2 (%/10°C) as temperature increased. CONCLUSION This study confirms that the scintillation survey meter with the temperature compensation function was less dependent on temperature, and stable measurement was possible. However, it was suggested that the scintillation survey meter without the temperature compensation function might cause a drop in the measured value as the temperature rises.
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Affiliation(s)
- Miku Furukawa
- Department of Radiological Technology, Faculty of Health Sciences, Tohoku University School of Medicine
| | - Rio Isobe
- Department of Radiological Technology, Faculty of Health Sciences, Tohoku University School of Medicine
| | - Saya Ono
- Department of Radiological Technology, Faculty of Health Sciences, Tohoku University School of Medicine
| | - Yusaku Gonai
- Department of Radiological Technology, Faculty of Health Sciences, Tohoku University School of Medicine
| | - Ryota Shindo
- Department of Radiological Technology, Faculty of Health Sciences, Tohoku University School of Medicine
| | - Keisuke Yamamoto
- Department of Radiological Technology, Faculty of Health Sciences, Tohoku University School of Medicine
| | - Yohei Inaba
- Department of Radiological Examination and Technology, Tohoku University Graduate School of Medicine
- Disaster Medical Radiology, Division of Disaster Medical Science, International Research Institute of Disaster Science, Tohoku University
| | - Koichi Chida
- Department of Radiological Examination and Technology, Tohoku University Graduate School of Medicine
- Disaster Medical Radiology, Division of Disaster Medical Science, International Research Institute of Disaster Science, Tohoku University
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Liu K, Holmes S, Schüler E, Beddar S. A comprehensive investigation of the performance of a commercial scintillator system for applications in electron FLASH radiotherapy. Med Phys 2024. [PMID: 38507253 DOI: 10.1002/mp.17030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 02/08/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND Dosimetry in ultra-high dose rate (UHDR) beamlines is significantly challenged by limitations in real-time monitoring and accurate measurement of beam output, beam parameters, and delivered doses using conventional radiation detectors, which exhibit dependencies in ultra-high dose-rate (UHDR) and high dose-per-pulse (DPP) beamline conditions. PURPOSE In this study, we characterized the response of the Exradin W2 plastic scintillator (Standard Imaging, Inc.), a water-equivalent detector that provides measurements with a time resolution of 100 Hz, to determine its feasibility for use in UHDR electron beamlines. METHODS The W2 scintillator was exposed to an UHDR electron beam with different beam parameters by varying the pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings of an electron UHDR linear accelerator system. The response of the W2 scintillator was evaluated as a function of the total integrated dose delivered, DPP, and mean and instantaneous dose rate. To account for detector radiation damage, the signal sensitivity (pC/Gy) of the W2 scintillator was measured and tracked as a function of dose history. RESULTS The W2 scintillator demonstrated mean dose rate independence and linearity as a function of integrated dose and DPP for DPP ≤ 1.5 Gy (R2 > 0.99) and PRF ≤ 90 Hz. At DPP > 1.5 Gy, nonlinear behavior and signal saturation in the blue and green signals as a function of DPP, PRF, and integrated dose became apparent. In the absence of Cerenkov correction, the W2 scintillator exhibited PW dependence, even at DPP values <1.5 Gy, with a difference of up to 31% and 54% in the measured blue and green signal for PWs ranging from 0.5 to 3.6 µs. The change in signal sensitivity of the W2 scintillator as a function of accumulated dose was approximately 4%/kGy and 0.3%/kGy for the measured blue and green signal responses, respectively, as a function of integrated dose history. CONCLUSION The Exradin W2 scintillator can provide output measurements that are both dose rate independent and linear in response if the DPP is kept ≤1.5 Gy (corresponding to a mean dose rate up to 290 Gy/s in the used system), as long as proper calibration is performed to account for PW and changes in signal sensitivity as a function of accumulated dose. For DPP > 1.5 Gy, the W2 scintillator's response becomes nonlinear, likely due to limitations in the electrometer related to the high signal intensity.
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Affiliation(s)
- Kevin Liu
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- UTHealth Houston Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - Emil Schüler
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- UTHealth Houston Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Sam Beddar
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- UTHealth Houston Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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18
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Píriz GH, Gonzalez-Sprinberg GA, Ballester F, Vijande J. Dosimetry of Large Field Valencia applicators for Cobalt-60-based brachytherapy. Med Phys 2024. [PMID: 38507246 DOI: 10.1002/mp.17035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/19/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND Non-melanoma skin cancer is one of the most common types of cancer and one of the main approaches is brachytherapy. For small lesions, the treatment of this cancer with brachytherapy can be done with two commercial applicators, one of these is the Large Field Valencia Applicators (LFVA). PURPOSE The aim of this study is to test the capabilities of the LFVA to use clinically 60Co sources instead of the 192Ir ones. This study was designed for the same dwell positions and weights for both sources. METHODS The Penelope Monte Carlo code was used to evaluate dose distribution in a water phantom when a 60Co source is considered. The LFVA design and the optimized dwell weights reported for the case of 192Ir are maintained with the only exception of the dwell weight of the central position, that was increased. 2D dose distributions, field flatness, symmetry and the leakage dose distribution around the applicator were calculated. RESULTS When comparing the dose distributions of both sources, field flatness and symmetry remain unchanged. The only evident difference is an increase of the penumbra regions for all depths when using the 60Co source. Regarding leakage, the maximum dose within the air volume surrounding the applicator is in the order of 20% of the prescription dose for the 60Co source, but it decreases to less than 5% at about 1 cm distance. CONCLUSIONS Flatness and symmetry remains unaltered as compared with 192Ir sources, while an increase in leakage has been observed. This proves the feasibility of using the LFVA in a larger range of clinical applications.
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Affiliation(s)
- Gustavo H Píriz
- Medical Physics Unit, Faculty of Sciences, University of the Republic, Montevideo, Uruguay
| | | | - Facundo Ballester
- Departamento de Física Atómica, Molecular y Nuclear, Universitat de Valencia (UV), Burjassot, Spain
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Ins-tituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), València, Spain
| | - Javier Vijande
- Departamento de Física Atómica, Molecular y Nuclear, Universitat de Valencia (UV), Burjassot, Spain
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Ins-tituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), València, Spain
- Instituto de Física Corpuscular, IFIC (UV-CSIC), Burjassot, Spain
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19
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Grandvillain M, Vidal M, Hérault J, Benabdesselam M, Hofverberg P, Mady F. Silica-based scintillators: basic properties of radioluminescence kinetics. J Phys Condens Matter 2024; 36:245701. [PMID: 38447159 DOI: 10.1088/1361-648x/ad3094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/06/2024] [Indexed: 03/08/2024]
Abstract
Radioluminescent silica-based fiber dosimeters offer great advantages for designing miniaturized realtime sensors for high dose-rate dosimetry. Rise and fall kinetics of their response must be properly understood to better assess their performances in terms of measurement speed and repeatability. A standard model of radioluminescence (RL) has already been quantitatively validated for doped silica glasses, but beyond conclusive comparisons with specific experiments, a comprehensive understanding of the processes and parameters determining transient and equilibrium kinetics of RL is still lacking. We analyze in detail the kinetics inherent in the standard RL model. Several asymptotical regimes in the RL growth are demonstrated in the case of a pristine sample (succesive quadratic, linear and power-law time dependencies before the plateau is reached). We show how this situation is modified when a pre-irradiation partly fills traps beforehand. RL growth is then greatly accelerated because of the pre-formation of recombination centers (RCs) from dopant ions, but not due to pre-filling of trapping levels. In all cases, the RL intensity eventually tends to a constant level equal to the pair generation rate, long before all carrier densities themselves reach equilibrium. This occurs late under irradiation, when deep traps get to saturation. The fraction of dopants converted into RCs is then 'frozen' at a lower level the smaller the density of deep traps. Controlling RL kinetics through the engineering of material traps is not an option. Pre-irradiation appears to be the simplest way to obtain accelerated and repeatable kinetics.
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Affiliation(s)
- Marjorie Grandvillain
- Université Côte d'Azur, Fédération de recherche Claude Lalanne, Institut de Physique de Nice, CNRS UMR7010, 17 rue Julien Lauprêtre, 06200 Nice, France
| | - Marie Vidal
- Centre Antoine Lacassagne, Fédération de recherche Claude Lalanne, 227 avenue de la Lanterne, 06200 Nice, France
| | - Joël Hérault
- Centre Antoine Lacassagne, Fédération de recherche Claude Lalanne, 227 avenue de la Lanterne, 06200 Nice, France
| | - Mourad Benabdesselam
- Université Côte d'Azur, Fédération de recherche Claude Lalanne, Institut de Physique de Nice, CNRS UMR7010, 17 rue Julien Lauprêtre, 06200 Nice, France
| | - Petter Hofverberg
- Centre Antoine Lacassagne, Fédération de recherche Claude Lalanne, 227 avenue de la Lanterne, 06200 Nice, France
| | - Franck Mady
- Université Côte d'Azur, Fédération de recherche Claude Lalanne, Institut de Physique de Nice, CNRS UMR7010, 17 rue Julien Lauprêtre, 06200 Nice, France
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20
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Jelen U, Pagulayan C, Moutrie Z, Arts J, George A, Jameson MG. Technical note: Cryostat transmission characterization for MR linac - temporal stability, clinical impact and change implementation. Med Phys 2024. [PMID: 38465398 DOI: 10.1002/mp.17021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 02/24/2024] [Accepted: 02/26/2024] [Indexed: 03/12/2024] Open
Abstract
BACKGROUND In the Unity MR linac (Elekta AB, Stockholm, Sweden), the radiation beam traverses the cryostat and the coil support structure. The resulting beam attenuation must be considered for output calibration and its variation with gantry angle must be characterized in the treatment planning system (TPS). PURPOSE The aim of this work was to investigate the impact of a change of the cryostat transmission characterization (CTC) curve, due to the helium level modification, on clinical treatment plan dosimetry and to report on the experience with the CTC curve update. METHODS Twenty stereotactic body radiotherapy (SBRT) treatment plans: 10 prostate and 10 oligo-metastatic cancer plans, prepared with a beam model incorporating the CTC curve acquired at installation time, were re-calculated using the model implementing CTC curve post helium top-up. To account for the CTC change as well as to align our system to the recent reference conditions recommendations, the new model was commissioned with the emphasis on the specifics associated with the treatment plan adaptation and the existence of the offline and online TPS components. RESULTS Average CTV mean dose reduction by 0.45% in prostate cases and average GTV mean dose reduction by 0.22% in oligo-metastatic cases was observed. Updated model validation showcased good agreement between measurements and TPS calculations. CONCLUSIONS The agreement between CTC measurements demonstrates its temporal constancy and robustness of the measurement method employed. A helium fill level change was shown to affect the CTC and led to a small but systematic dose calculation inaccuracy. Finally, model validation and end-to-end testing results presented, underscore the minimal impact of transitioning to the new beam model and new reference conditions.
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Affiliation(s)
| | | | - Zoë Moutrie
- South Western Sydney Cancer Services, New South Wales Health, Liverpool, NSW, Australia
- South West Sydney Clinical Campuses, University of New South Wales, Warwick Farm, NSW, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Jason Arts
- Elekta Pty Ltd, North Sydney, NSW, Australia
| | | | - Michael G Jameson
- GenesisCare, Alexandria, NSW, Australia
- University of New South Wales, Sydney, NSW, Australia
- University of Wollongong, Wollongong, NSW, Australia
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21
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Kayal G, Van B, Andl G, Tu C, Wareing T, Wilderman S, Mikell J, Dewaraja YK. Linear Boltzmann equation solver for voxel-level dosimetry in radiopharmaceutical therapy: Comparison with Monte Carlo and kernel convolution. Med Phys 2024. [PMID: 38436493 DOI: 10.1002/mp.16996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 01/12/2024] [Accepted: 01/28/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND With recent interest in patient-specific dosimetry for radiopharmaceutical therapy (RPT) and selective internal radiation therapy (SIRT), an increasing number of voxel-based algorithms are being evaluated. Monte Carlo (MC) radiation transport, generally considered to be the most accurate among different methods for voxel-level absorbed dose estimation, can be computationally inefficient for routine clinical use. PURPOSE This work demonstrates a recently implemented grid-based linear Boltzmann transport equation (LBTE) solver for fast and accurate voxel-based dosimetry in RPT and SIRT and benchmarks it against MC. METHODS A deterministic LBTE solver (Acuros MRT) was implemented within a commercial RPT dosimetry package (Velocity 4.1). The LBTE is directly discretized using an adaptive mesh refined grid and then the coupled photon-electron radiation transport is iteratively solved inside specified volumes to estimate radiation doses from both photons and charged particles in heterogeneous media. To evaluate the performance of the LBTE solver for RPT and SIRT applications, 177 Lu SPECT/CT, 90 Y PET/CT, and 131 I SPECT/CT images of phantoms and patients were used. Multiple lesions (2-1052 mL) and normal organs were delineated for each study. Voxel dosimetry was performed with the LBTE solver, dose voxel kernel (DVK) convolution with density correction, and a validated in-house MC code using the same time-integrated activity and density maps as input to the different dose engines. The resulting dose maps, difference maps, and dose-volume-histogram (DVH) metrics were compared, to assess the voxel-level agreement. Evaluation of mean absorbed dose included comparison with structure-level estimates from OLINDA. RESULTS In the phantom inserts/compartments, the LBTE solver versus MC and DVK convolution demonstrated good agreement with mean absorbed dose and DVH metrics agreeing to within 5% except for the D90 and D70 metrics of a very low activity concentration insert of 90 Y where the agreement was within 15%. In the patient studies (five patients imaged after 177 Lu DOTATATE RPT, five after 90 Y SIRT, and two after 131 I radioimmunotherapy), in general, there was better agreement between the LBTE solver and MC than between LBTE solver and DVK convolution for mean absorbed dose and voxel-level evaluations. Across all patients for all three radionuclides, for soft tissue structures (kidney, liver, lesions), the mean absorbed dose estimates from the LBTE solver were in good agreement with those from MC (median difference < 1%, maximum 9%) and those from DVK (median difference < 5%, maximum 9%). The LBTE and OLINDA estimates for mean absorbed dose in kidneys and liver agreed to within 10%, but differences for lesions were larger with a maximum 14% for 177 Lu, 23% for 90 Y, and 26% for 131 I. For bone regions, the agreement in mean absorbed doses between LBTE and both MC and DVK were similar (median < 11%, max 11%) while for lung the agreement between LBTE and MC (median < 1%, max 8%) was substantially better than between LBTE and DVK (median < 16%, max 33%). Voxel level estimates for soft tissue structures also showed good agreement between the LBTE solver and both MC and DVK with a median difference < 5% (maximum < 13%) for the DVH metrics with all three radionuclides. The largest difference in DVH metrics was for the D90 and D70 metric in lung and bone where the uptake was low. Here, the difference between LBTE and MC had a median value < 14% (maximum 23%) for bone and < 4% (maximum 37%) for lung, while the corresponding differences between LBTE and DVK were < 23% (maximum 31%) and < 67% (maximum 313%), respectively. For a typical patient with a matrix size of 166 × 166 × 129 (voxel size 3 × 3 × 3 mm3 ), voxel dosimetry using the LBTE solver was as fast as ∼2 min on a desktop computer. CONCLUSION Having established good agreement between the LBTE solver and MC for RPT and SIRT applications, the LBTE solver is a viable option for voxel dosimetry that can be faster than MC. Further analysis is being performed to encompass the broad range of radionuclides and conditions encountered clinically.
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Affiliation(s)
- Gunjan Kayal
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Benjamin Van
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - George Andl
- Varian Medical Systems, Atlanta, Georgia, USA
| | - Cheng Tu
- Varian Medical Systems, Atlanta, Georgia, USA
| | | | - Scott Wilderman
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Justin Mikell
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - Yuni K Dewaraja
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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22
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Mori A, Ito S, Sekine T. A revision of the multiple-path particle dosimetry model focusing on tobacco product aerosol dynamics. Int J Numer Method Biomed Eng 2024; 40:e3796. [PMID: 38185887 DOI: 10.1002/cnm.3796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/15/2023] [Accepted: 11/26/2023] [Indexed: 01/09/2024]
Abstract
To assess the health impact of inhaled aerosols, it is necessary to understand aerosol dynamics and the associated dosimetry in the human respiratory tract. Although several studies have measured or simulated the dosimetry of aerosol constituents, the respiratory tract focus areas have been limited. In particular, the aerosols generated from tobacco products are complex composites and simulating their dynamics in the respiratory tract is challenging. To assess the dosimetry of the aerosol constituents of tobacco products, we developed a revised version of the Multiple-Path Particle Dosimetry (MPPD) model, which employs (1) new geometry based on CT-scanned human respiratory tract data, (2) convective mixing in the oral cavity and deep lung, and (3) constituent partitioning between the tissue and air, and clearance. The sensitivity analysis was conducted using aerosols composed of four major constituents of electronic cigarette (EC) aerosols to investigate the parameters that have a significant impact on the results. In addition, the revised model was run with 4 and 10 constituents in ECs and conventional cigarettes (CCs), respectively. Sensitivity analysis revealed that the new modeling and the physicochemical properties of constituents had a considerable impact on the simulated aerosol concentration and dosimetry. The simulations could be carried out within 3 min even when 10 constituents of CC aerosols were analyzed simultaneously. The revised model based on MPPD is an efficient and easy-to-use tool for understanding the aerosol dynamics of CC and EC constituents and their effect on the human body.
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Affiliation(s)
- Akina Mori
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
| | - Shigeaki Ito
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
| | - Takashi Sekine
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
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23
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Takatsu J, Murakami N, Muramoto Y, Karino T, Oshima M, Kosugi Y, Kawamoto T, Terao Y, Shikama N. Safe dose escalation and reduction of the fraction number of uterine cervical brachytherapy using a gel spacer in the rectovaginal and vesicouterine septum: A planning study. Brachytherapy 2024; 23:115-122. [PMID: 38040605 DOI: 10.1016/j.brachy.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/22/2023] [Accepted: 10/06/2023] [Indexed: 12/03/2023]
Abstract
PURPOSE To evaluate the possibility of dose escalation and reduction of fraction number in cervical brachytherapy using a gel spacer. MATERIAL AND METHODS Twenty patients with uterine cervical cancer treated with image-guided adaptive brachytherapy (IGABT) were selected. Hyaluronic acid gel injection (HGI) was performed in the rectovaginal and vesicouterine septum for 10 patients. The other ten patients were not with HGI. Both groups were treated with IGABT involving tandem/ovoid or cylindrical applicators along with additional interstitial needles. Dose distributions approved by radiation oncologists were retrospectively analyzed, and a dose summation of 45 Gy/25 of external beam radiation therapy and IGABT was performed. Dose constraints for D2cc of bladder, rectum, and sigmoid were 80, 70, and 70 Gy, respectively. Equivalent dose in 2-Gy fractions calculations used α/β = 10 Gy for high-risk clinical target volume (CTVHR) D90 and α/β = 3 Gy for organs at risks (OARs). As a planning study, dose distribution rescaling was conducted to deliver as much dose to CTVHR D90 as possible within the dose constraint limitation for OARs when IGABT was performed for four, three, and two fractions in both groups. RESULTS The median CTVHR D90 was >80 Gy in the non-HGI group and >85 Gy in the HGI group for virtual two and three fractions. Rectum D2cc was significantly lower in the HGI group for three fractions (p < 0.01). CONCLUSIONS In the HGI group, adequate dose delivery to CTVHR could be achieved with a reduced IGABT fraction number while meeting the dose constraints of OARs.
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Affiliation(s)
- Jun Takatsu
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Naoya Murakami
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan.
| | - Yoichi Muramoto
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Tatsuki Karino
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Masaki Oshima
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Yasuo Kosugi
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Terufumi Kawamoto
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Yasuhisa Terao
- Department of Obstetrics and Gynecology, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Naoto Shikama
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, Japan
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Gao L, Wei R, Qin S, Tian Y, Xia W, Song Y, Wang S, Fang H, Tang Y, Jing H, Liu Y, Tang Y, Qi S, Chen B, Li Y, Xing N, Lu N. Adaptive ultra-hypofractionated whole-pelvic radiotherapy in high-risk and very high-risk prostate cancer on 1.5-Tesla MR-Linac: Estimated delivered dose and early toxicity results. Chronic Dis Transl Med 2024; 10:51-61. [PMID: 38450305 PMCID: PMC10914013 DOI: 10.1002/cdt3.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/17/2023] [Accepted: 12/25/2023] [Indexed: 03/08/2024] Open
Abstract
Background Magnetic resonance (MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation (UHF-WPRT) is a novel approach to radiotherapy for patients with high-risk (HR) and very high-risk (VHR) prostate cancer (PCa). However, the inherent complexity of adaptive UHF-WPRT might inevitably result in longer on-couch time. We aimed to estimate the delivered dose, study the feasibility and safety of adaptive UHF-WPRT on a 1.5-Tesla MR-Linac. Methods Ten patients with clinical stage T3a-4N0-1M0-1c PCa, who consecutively received UHF-WPRT, were enrolled prospectively. The contours of the target and organ-at-risks on the position verification-MR (PV-MR), beam-on 3D-MR(Bn-MR), and post-MR (after radiotherapy delivery) were derived from the pre-MR data by deformable image registration. The physician then manually adjusted them, and dose recalculation was performed accordingly. GraphPad Prism 9 (GraphPad Prism Software Inc.) was utilized for conducting statistical analyses. Results In total, we collected 188 MR scans (50 pre-MR, 50 PV-MR, 44 Bn-MR, and 44 post-MR scans). With median 59 min, the mean prostate clinical target volume (CTV)-V100% was 98.59% ± 2.74%, and the mean pelvic CTVp-V100% relative percentages of all scans was 99.60% ± 1.18%. The median V29 Gy change in the rectal wall was -2% (-18% to 20%). With a median follow-up of 9 months, no patient had acute Common Terminology Criteria for Adverse Events (CTCAE) grade 2 or more severe genitourinary (GU) or gastrointestinal (GI) toxicities (0%). Conclusion UHF-RT to the prostate and the whole pelvis with concomitant boost to positive nodes using an Adapt-To-Shape (ATS) workflow was technically feasible for patients with HR and VHR PCa, presenting only mild GU and GI toxicities. The estimated target dose during the beam-on phase was clinically acceptable based on the 3D-MR-based dosimetry analysis. Clinical trial registration Chinese Clinical Trial Registry ChiCTR2000033382.
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Affiliation(s)
- Linrui Gao
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Ran Wei
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Shirui Qin
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yuan Tian
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Wenlong Xia
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yongwen Song
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Shulian Wang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Hui Fang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yu Tang
- GCP Center/Clinical Research Center, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Hao Jing
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yueping Liu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yuan Tang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Shunan Qi
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Bo Chen
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yexiong Li
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Nianzeng Xing
- Department of Urology, State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Ningning Lu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
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Yen A, Zhong X, Lin MH, Nwachukwu C, Albuquerque K, Hrycushko B. Improved Dosimetry with Daily Online Adaptive Radiotherapy for Cervical Cancer: Waltzing the Pear. Clin Oncol (R Coll Radiol) 2024; 36:165-172. [PMID: 38246849 DOI: 10.1016/j.clon.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 12/04/2023] [Accepted: 01/09/2024] [Indexed: 01/23/2024]
Abstract
AIMS Standard of care radiotherapy for locally advanced cervical cancer includes large margins to ensure the uterocervix remains within the treatment fields over the course of treatment. Daily online cone-beam adaptive radiotherapy corrects for interfractional changes by adjusting the plan to match the target position during each treatment session, thus allowing for significantly reduced clinical target volume (CTV) to planning target volume (PTV) margins. We hypothesise that reduced margins from daily online adaptive radiotherapy will reduce organ at risk dose without compromising target coverage. MATERIALS AND METHODS Ten patients with cervical cancer (stage IIB-IIIC2) were treated with definitive chemoradiation using daily online cone-beam adaptive radiotherapy in 25-27 fractions. Initial and all adapted treatment plans were generated with CTV to PTV margins versus standard of care image-guided radiotherapy (IGRT) plans as follows: cervix/uterus/gross tumour volume (0.5 versus 1.5 cm), parametria/vagina (0.5 versus 1.0 cm) and nodal chains and gross nodes (0.5 versus 0.5 cm). IGRT plans were created and copied to synthetic computed tomography scans and contours generated from each daily adapted fraction. The dosimetry of each clinically treated online adapted fraction was compared with emulated IGRT plans. Statistical significance was defined as P < 0.05. RESULTS Daily online cone-beam adaptive radiotherapy significantly improves bowel bag dosimetry compared with IGRT, with a reduction in V40 by an average of 91.3 cm3 [V40 (-6.2%) and V45 (-6.1%)]. The daily adapted plans showed significant improvements in bladder and rectum [V40 (-25.2% and -36.0%) and V30 (-9.7% and -17.1%), respectively]. Additionally, bone marrow had a significantly reduced dose [V10 (-2.7%) and V20 (-3.3%)]. Daily online cone-beam adaptive radiotherapy improved uterocervix CTV coverage and reduced hotspots compared with IGRT [D95% (+1.6%) and Dmax (-0.9%)]. CONCLUSIONS Reduced CTV to PTV margins achievable with daily online adaptive radiotherapy improves organ at risk dosimetry and target coverage when compared with standard of care IGRT for locally advanced cervical cancer. The clinical impact of improved dosimetry is currently undergoing investigation.
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Affiliation(s)
- A Yen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - X Zhong
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - M-H Lin
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - C Nwachukwu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - K Albuquerque
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - B Hrycushko
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
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Alzahrani HM. The impact of sinusitis on dose distribution in a radiotherapy plan by in silico study. Saudi Med J 2024; 45:235-240. [PMID: 38438210 DOI: 10.15537/smj.2024.45.3.20230520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 01/07/2024] [Indexed: 03/06/2024] Open
Abstract
OBJECTIVES To assess the impact of changes in sinus aeration on dose variation in nasopharyngeal cases using a single beam with various field sizes and real patient computed tomography (CT) images. METHODS The calculations were carried out on a computer equipped with an Intel Xeon (R) Gold 5118 processor operating at 2.30 GHz in 2022 at Taibah University, Al Madinah Al Munawwarah for a retrospective nasopharyngeal case. At the patient level, the impact on dose distribution was examined for different field sizes by comparing the percentage depth dose. The dose discrepancy was evaluated by comparing the dose delivered without considering the anatomical changes observed in the initial fraction to the dose adjusted to account for these changes using a 2D gamma analysis. With a criterion of 1% dose difference and 1 mm distance to agreement, the gamma level for analysis was set at 95%. RESULTS The study findings indicated that the observed effect diminished by approximately 50% for both 5 cm x 5 cm and 10 cm x 10 cm field sizes compared to the 3 cm x 3 cm size, where there was an overlap between the planning target volume and sinusitis. CONCLUSION The study concluded that the impact of dose discrepancy was more pronounced in smaller field sizes.
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Affiliation(s)
- Hanan M Alzahrani
- From the Department of Radiology Technology, College of Applied Medical Sciences, Taibah University, Al Madinah Al Munawwarah, Kingdom of Saudi Arabia
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Schaefer-Schuler A, Burgard C, Blickle A, Maus S, Petrescu C, Petto S, Bartholomä M, Stemler T, Ezziddin S, Rosar F. [ 161Tb]Tb-PSMA-617 radioligand therapy in patients with mCRPC: preliminary dosimetry results and intra-individual head-to-head comparison to [ 177Lu]Lu-PSMA-617. Theranostics 2024; 14:1829-1840. [PMID: 38505615 PMCID: PMC10945337 DOI: 10.7150/thno.92273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/19/2024] [Indexed: 03/21/2024] Open
Abstract
Rationale: Evaluation of alternative radionuclides for use in prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) is currently focusing on 161Tb, which may provide advantages by emitting additional Auger and conversion electrons. In this pilot study, we present preliminary dosimetry data for [161Tb]Tb-PSMA-617 RLT in a direct comparison with [177Lu]Lu-PSMA-617. Method: Six patients with metastatic castration-resistant prostate cancer (mCRPC) underwent treatment with [177Lu]Lu-PSMA-617 and subsequently - after inadequate response - with [161Tb]Tb-PSMA-617. Whole-body planar and SPECT imaging-based dosimetry of organs at risk (kidneys and salivary glands) and tumor lesions were calculated using IDAC for 177Lu and OLINDA/EXM for 161Tb. The therapeutic index (TI) of mean tumor-absorbed doses over relevant organs at risk was calculated. Results: Mean absorbed doses to organs at risk of PSMA-RLT were slightly higher for [161Tb]Tb-PSMA-617 compared to [177Lu]Lu-PSMA-617 (kidneys: 0.643 ± 0.247 vs. 0.545 ± 0.231 Gy/GBq, factor 1.18; parotid gland: 0.367 ± 0.198 vs. 0.329 ± 0.180 Gy/GBq, factor 1.10), but markedly higher regarding tumor lesions (6.10 ± 6.59 vs 2.59 ± 3.30 Gy/GBq, factor 2.40, p < 0.001). Consequently, the mean TI was higher for [161Tb]Tb-PSMA-617 compared to [177Lu]Lu-PSMA-617 for both, the kidneys (11.54 ± 9.74 vs. 5.28 ± 5.13, p = 0.002) and the parotid gland (16.77 ± 13.10 vs. 12.51 ± 18.09, p = 0.008). Conclusion: In this intra-individual head-to-head pilot study, [161Tb]Tb-PSMA-617 delivered higher tumor-absorbed doses and resulted in superior TI compared to [177Lu]Lu-PSMA-617. This preliminary data support 161Tb as a promising radionuclide for PSMA-RLT in mCRPC.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Florian Rosar
- Department of Nuclear Medicine, Saarland University, Medical Center, Homburg, Germany
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Ramadhan MM, Wibowo WE, Prajitno P, Pawiro SA. Comparison of deep learning models for building two-dimensional non-transit EPID Dosimetry on Varian Halcyon. Rep Pract Oncol Radiother 2024; 28:737-745. [PMID: 38515817 PMCID: PMC10954275 DOI: 10.5603/rpor.98729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/04/2023] [Indexed: 03/23/2024] Open
Abstract
Background This study compared the effectiveness of five deep learning models in constructing non-transit dosimetry with an a-Si electronic portal imaging device (EPID) on Varian Halcyon. Deep learning model is increasingly used to support prediction and decision-making in several fields including oncology and radiotherapy. Materials and methods Forty-seven unique plans of data obtained from breast cancer patients were calculated using Eclipse treatment planning system (TPS) and extracted from DICOM format as the ground truth. Varian Halcyon was then used to irradiate the a-Si 1200 EPID detector without an attenuator. The EPID and TPS images were augmented and divided randomly into two groups of equal sizes to distinguish the validation and training-test data. Five different deep learning models were then created and validated using a gamma index of 3%/3 mm. Results Four models successfully improved the similarity of the EPID images and the TPS-generated planned dose images. Meanwhile, the mismatch of the constituent components and number of parameters could cause the models to produce wrong results. The average gamma pass rates were 90.07 ± 4.96% for A-model, 77.42 ± 7.18% for B-model, 79.60 ± 6.56% for C-model, 80.21 ± 5.88% for D-model, and 80.47 ± 5.98% for E-model. Conclusion The deep learning model is proven to run fast and can increase the similarity of EPID images with TPS images to build non-transit dosimetry. However, more cases are needed to validate this model before being used in clinical activities.
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Affiliation(s)
- Muhammad Mahdi Ramadhan
- Department Physics, Faculty of Mathematics and Natural Sciences Universitas Indonesia, Depok, Indonesia
| | - Wahyu Edy Wibowo
- Department of Radiation Oncology, Dr. Cipto Mangunkusumo General Hospital, Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia
| | - Prawito Prajitno
- Department Physics, Faculty of Mathematics and Natural Sciences Universitas Indonesia, Depok, Indonesia
| | - Supriyanto Ardjo Pawiro
- Department Physics, Faculty of Mathematics and Natural Sciences Universitas Indonesia, Depok, Indonesia
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Guillou M, L'Homme B, Trompier F, Errabii A, Marcoux T, Gruel G, Prezado Y, Dos Santos M. Radiological injuries under low energy x-rays in mice depending on dose and protocol: comparative characterization of lesion severity and impact of the in vivobone response on retrospective dose estimations. Phys Med Biol 2024; 69:045035. [PMID: 38211312 DOI: 10.1088/1361-6560/ad1d69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
Objective. To improve our knowledge about the biological effects of over exposures involving low-energy x-rays, we developed and characterized a preclinical mouse model allowing to mimic different lesion severity degrees induced by 80 kV x-ray depending on the dose and protocol (single or repeated exposure).Approach. Mice were locally exposed (paw) to 80 kV x-rays in a single (15, 30 or 45 Gy inKair) or repeated exposition (2 × 15 or 3 × 15 Gy inKair) to assess different degrees of lesion severity. Six post-irradiation euthanasia time points (0, 7, 14, 21, 42, and 84 days) were determined to follow up the evolution of lesions based on the lesion score, weighing and cutaneous blood perfusion. The bone dose was estimated at the different time points by electron paramagnetic resonance (EPR) spectroscopy.Main results. The monitoring of the lesion severity allows to classify the exposure protocols according to their severity. EPR spectroscopy measurements allow to determine the bone dose on the day of irradiation which is 7 times higher than the initial dose for single protocols. However, the initial signal measured at the end of the repeated exposure was 27% lower than the signal measured for a single dose. The study of the kinetics of EPR signal showed a decrease of the EPR signal which is dependent on the exposure protocol but not on dose highlighting the impact of bone physiology on the bone dose estimation.Significance: the preclinical model developed allows to assess the impact of the dose and protocol on the lesion severity induced by low-energy x-ray. For the first time, the dynamics of free radicals have been quantified in anin vivomodel, highlighting that the doses actually administered can be underestimated if samples are taken weeks or even months after exposure.
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Affiliation(s)
- Manon Guillou
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of RAdiobiology and regenerative MEDicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc) Fontenay-aux-Roses, France
| | - Bruno L'Homme
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of RAdiobiology and regenerative MEDicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc) Fontenay-aux-Roses, France
| | - François Trompier
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of DOSimetry, (SDOS), Ionizing Radiation Dosimetry Laboratory (LDRI), Fontenay-aux-Roses, F-92260, France
| | - Anass Errabii
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of RAdiobiology and regenerative MEDicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc) Fontenay-aux-Roses, France
| | - Tifanie Marcoux
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of RAdiobiology and regenerative MEDicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc) Fontenay-aux-Roses, France
| | - Gaëtan Gruel
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of RAdiobiology and regenerative MEDicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc) Fontenay-aux-Roses, France
| | - Yolanda Prezado
- Institut Curie, University Paris Saclay, PSL Research University, Inserm U 1021-CNRS UMR F-3347, Orsay, France
| | - Morgane Dos Santos
- Institute for Radiological Protection and Nuclear Safety (IRSN), Department of RAdiobiology and regenerative MEDicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc) Fontenay-aux-Roses, France
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Drake LR, Wu Y, Naganawa M, Asch R, Zheng C, Najafzadeh S, Pracitto R, Lindemann M, Li S, Ropchan J, Labaree D, Emery PR, Dias M, Henry S, Nabulsi N, Matuskey D, Hillmer AT, Gallezot JD, Carson RE, Cai Z, Huang Y. First-in-Human Study of 18F-SynVesT-2: An SV2A PET Imaging Probe with Fast Brain Kinetics and High Specific Binding. J Nucl Med 2024; 65:jnumed.123.266470. [PMID: 38360052 PMCID: PMC10924160 DOI: 10.2967/jnumed.123.266470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 02/17/2024] Open
Abstract
PET imaging of synaptic vesicle glycoprotein 2A allows for noninvasive quantification of synapses. This first-in-human study aimed to evaluate the kinetics, test-retest reproducibility, and extent of specific binding of a recently developed synaptic vesicle glycoprotein 2A PET ligand, (R)-4-(3-(18F-fluoro)phenyl)-1-((3-methylpyridin-4-yl)methyl)pyrrolidine-2-one (18F-SynVesT-2), with fast brain kinetics. Methods: Nine healthy volunteers participated in this study and were scanned on a High Resolution Research Tomograph scanner with 18F-SynVesT-2. Five volunteers were scanned twice on 2 different days. Five volunteers were rescanned with preinjected levetiracetam (20 mg/kg, intravenously). Arterial blood was collected to calculate the plasma free fraction and generate the arterial input function. Individual MR images were coregistered to a brain atlas to define regions of interest for generating time-activity curves, which were fitted with 1- and 2-tissue-compartment (1TC and 2TC) models to derive the regional distribution volume (V T). The regional nondisplaceable binding potential (BP ND) was calculated from 1TC V T, using the centrum semiovale (CS) as the reference region. Results: 18F-SynVesT-2 was synthesized with high molar activity (187 ± 69 MBq/nmol, n = 19). The parent fraction of 18F-SynVesT-2 in plasma was 28% ± 8% at 30 min after injection, and the plasma free fraction was high (0.29 ± 0.04). 18F-SynVesT-2 entered the brain quickly, with an SUVpeak of 8 within 10 min after injection. Regional time-activity curves fitted well with both the 1TC and the 2TC models; however, V T was estimated more reliably using the 1TC model. The 1TC V T ranged from 1.9 ± 0.2 mL/cm3 in CS to 7.6 ± 0.8 mL/cm3 in the putamen, with low absolute test-retest variability (6.0% ± 3.6%). Regional BP ND ranged from 1.76 ± 0.21 in the hippocampus to 3.06 ± 0.29 in the putamen. A 20-min scan was sufficient to provide reliable V T and BP ND Conclusion: 18F-SynVesT-2 has fast kinetics, high specific uptake, and low nonspecific uptake in the brain. Consistent with the nonhuman primate results, the kinetics of 18F-SynVesT-2 is faster than the kinetics of 11C-UCB-J and 18F-SynVesT-1 in the human brain and enables a shorter dynamic scan to derive physiologic information on cerebral blood flow and synapse density.
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Affiliation(s)
| | - Yanjun Wu
- Yale PET Center, New Haven, Connecticut
| | | | - Ruth Asch
- Yale PET Center, New Haven, Connecticut
| | | | | | | | | | - Songye Li
- Yale PET Center, New Haven, Connecticut
| | | | | | | | - Mark Dias
- Yale PET Center, New Haven, Connecticut
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Mohanty S, Patil D, Joshi K, Gamre P, Mishra A, Khairnar S, Kakoti S, Nayak L, Punatar S, Jain J, Phurailatpam R, Goda JS. Dosimetric Impact of Voluntary Deep Inspiration Breath Hold (DIBH) in Mediastinal Hodgkin Lymphomas: A Comparative Evaluation of Three Different Intensity Modulated Radiation Therapy (IMRT) Delivery Methods Using Voluntary DIBH and Free Breathing Techniques. Cancers (Basel) 2024; 16:690. [PMID: 38398081 PMCID: PMC10886974 DOI: 10.3390/cancers16040690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 12/26/2023] [Accepted: 01/08/2024] [Indexed: 02/25/2024] Open
Abstract
Hodgkin lymphomas are radiosensitive and curable tumors that often involve the mediastinum. However, the application of radiation therapy to the mediastinum is associated with late effects including cardiac and pulmonary toxicities and secondary cancers. The adoption of conformal IMRT and deep inspiration breath- hold (DIBH) can reduce the dose to healthy normal tissues (lungs, heart and breast). We compared the dosimetry of organs at risk (OARs) using different IMRT techniques for two breathing conditions, i.e., deep inspiration breath hold (DIBH) and free breathing. Twenty-three patients with early-stage mediastinal Hodgkin lymphomas were accrued in the prospective study. The patients were given treatment plans which utilized full arc volumetric modulated arc therapy (F-VMAT), Butterfly VMAT (B-VMAT), and fixed field IMRT (FF-IMRT) techniques for both DIBH and free breathing methods, respectively. All the plans were optimized to deliver 95% of the prescription dose which was 25.2 Gy to 95% of the PTV volume. The mean dose and standard error of the mean for each OAR, conformity index (CI), and homogeneity index (HI) for the target using the three planning techniques were calculated and compared using Student's t-test for parametric data and Wilcoxon signed-rank test for non-parametric data. The HI and CI of the target was not compromised using the DIBH technique for mediastinal lymphomas. The mean values of CI and HI for both DIBH and FB were comparable. The mean heart doses were reduced by 2.1 Gy, 2.54 Gy, and 2.38 Gy in DIBH compared to FB for the F-VMAT, B-VMAT, and IMRT techniques, respectively. There was a significant reduction in V5Gy, V10Gy, and V15Gy to the heart (p < 0.005) with DIBH. DIBH reduced the mean dose to the total lung by 1.19 Gy, 1.47 Gy, and 1.3 Gy, respectively. Among the 14 female patients, there was a reduction in the mean right breast dose with DIBH compared to FB (4.47 Gy vs. 3.63 Gy, p = 0.004). DIBH results in lower heart, lung, and breast doses than free breathing in mediastinal Hodgkin Lymphoma. Among the different IMRT techniques, FF-IMRT, B-VMAT, and F-VMAT showed similar PTV coverage, with similar conformity and homogeneity indices. However, the time taken for FF-IMRT was much longer than for the F-VMAT and B-VMAT techniques for both breathing methods. B-VMAT and F-VMAT emerged as the optimal planning techniques able to achieve the best target coverage and lower doses to the OARs, with less time required to deliver the prescribed dose.
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Affiliation(s)
- Samarpita Mohanty
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Divya Patil
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Kishore Joshi
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Poonam Gamre
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Ajay Mishra
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Sunil Khairnar
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Sangeeta Kakoti
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Lingaraj Nayak
- Department of Hemato Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (L.N.); (S.P.)
| | - Sachin Punatar
- Department of Hemato Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (L.N.); (S.P.)
| | - Jeevanshu Jain
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Reena Phurailatpam
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
| | - Jayant S. Goda
- Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai 410210, India; (S.M.); (D.P.); (K.J.); (P.G.); (A.M.); (S.K.); (S.K.); (J.J.); (R.P.)
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Mileva M, Marin G, Levillain H, Artigas C, Van Bogaert C, Marin C, Danieli R, Deleporte A, Picchia S, Stathopoulos K, Jungels C, Vanderlinden B, Paesmans M, Ameye L, Critchi G, Taraji-Schiltz L, Velghe C, Wimana Z, Bali M, Hendlisz A, Flamen P, Karfis I. Prediction of 177Lu-DOTATATE PRRT Outcome Using Multimodality Imaging in Patients with Gastroenteropancreatic Neuroendocrine Tumors: Results from a Prospective Phase II LUMEN Study. J Nucl Med 2024; 65:236-244. [PMID: 38164576 DOI: 10.2967/jnumed.123.265987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/25/2023] [Indexed: 01/03/2024] Open
Abstract
Our objective was to predict the outcome of peptide receptor radionuclide therapy (PRRT) using multimodality imaging and tumor dosimetry on gastroenteropancreatic neuroendocrine tumor (GEP-NET) lesions and patients. Methods: This prospective study included patients with progressive GEP-NETs. Treatment consisted of 4 cycles of 7.4 GBq of 177Lu-DOTATATE. Imaging parameters were measured on 68Ga-DOTATATE PET/CT (SUVmax/mean, somatostatin receptor [SSTR] tumor volume [TV], total lesion SSTR expression, and tumor-to-blood and tumor-to-spleen ratios), 18F-FDG PET/CT (SUVmax/mean, metabolically active TV, and total lesion glycolysis), and diffusion-weighted MRI (apparent diffusion coefficient) in a maximum of 5 target lesions per patient at approximately 10 wk after each injection. Tumor dosimetry was performed using SPECT/CT at 3 time points for every cycle. Baseline imaging parameters, their relative changes after PRRT cycle 1 (C1), and the tumor-absorbed dose at C1 were correlated with lesion morphologic outcome. The average values of the imaging parameters and the minimal, maximal, and mean C1 tumor-absorbed dose in each patient were tested for association with progression-free survival (PFS) and best objective response (RECIST 1.1). Results: In the 37 patients, the median PFS was 28 mo. Eleven of the 37 (30%) achieved a partial response (RECIST 1.1). After a median follow-up of 57 mo, the median time to lesion progression had not been reached in 84 morphologically evaluable lesions, with only 12 (14%) progressing (size increase ≥ 20% from baseline). Patients receiving a minimal C1 dose of 35 Gy in all target lesions exhibited a significantly longer PFS (48.1 vs. 26.2 mo; hazard ratio, 0.37; 95% CI, 0.17-0.82; P = 0.02). Volumetric 68Ga-DOTATATE PET parameters correlated with lesion and patient outcome: patients with an SSTR TV decrease of more than 10% after C1 had a longer PFS (51.3 vs. 22.8 mo; hazard ratio, 0.35; 95% CI, 0.16-0.75; P = 0.003). There was no statistical evidence of an association between other dosimetric or imaging parameters and the lesion or patient outcome. Conclusion: Minimal tumor-absorbed dose at C1 is predictive of outcome in patients with GEP-NETs treated with PRRT, providing a basis for personalized dosimetry-guided treatment strategies. An SSTR TV decrease after C1 could be used for early therapy response assessment as a predictor of PRRT outcome.
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Affiliation(s)
- Magdalena Mileva
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Gwennaëlle Marin
- Medical Physics Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Hugo Levillain
- Medical Physics Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Carlos Artigas
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Camille Van Bogaert
- Nuclear Medicine Department, CUB-Hôpital Erasme, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Clémentine Marin
- Medical Physics Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Rachele Danieli
- Medical Physics Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Amelie Deleporte
- Medical Oncology Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Simona Picchia
- Radiology Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Konstantinos Stathopoulos
- Radiology Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Christiane Jungels
- Medical Oncology Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Bruno Vanderlinden
- Medical Physics Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Marianne Paesmans
- Data Center, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium; and
| | - Lieveke Ameye
- Data Center, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium; and
| | - Gabriela Critchi
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Loubna Taraji-Schiltz
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Chloe Velghe
- Data Center, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium; and
| | - Zéna Wimana
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
- Radiopharmacy Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Maria Bali
- Radiology Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Alain Hendlisz
- Medical Oncology Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Patrick Flamen
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Ioannis Karfis
- Nuclear Medicine Department, Institut Jules Bordet, ENETS Centre of Excellence, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium;
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Benabdallah N, Lu P, Abou DS, Zhang H, Ulmert D, Hobbs RF, Gay HA, Simons BW, Saeed MA, Rogers BE, Jha AK, Tai YC, Malone CD, Ippolito JE, Michalski J, Jennings JW, Baumann BC, Pachynski RK, Thorek DLJ. Beyond Average: α-Particle Distribution and Dose Heterogeneity in Bone Metastatic Prostate Cancer. J Nucl Med 2024; 65:245-251. [PMID: 38124163 PMCID: PMC10858382 DOI: 10.2967/jnumed.123.266571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/23/2023] [Indexed: 12/23/2023] Open
Abstract
α-particle emitters are emerging as a potent modality for disseminated cancer therapy because of their high linear energy transfer and localized absorbed dose profile. Despite great interest and pharmaceutical development, there is scant information on the distribution of these agents at the scale of the α-particle pathlength. We sought to determine the distribution of clinically approved [223Ra]RaCl2 in bone metastatic castration-resistant prostate cancer at this resolution, for the first time to our knowledge, to inform activity distribution and dose at the near-cell scale. Methods: Biopsy specimens and blood were collected from 7 patients 24 h after administration. 223Ra activity in each sample was recorded, and the microstructure of biopsy specimens was analyzed by micro-CT. Quantitative autoradiography and histopathology were segmented and registered with an automated procedure. Activity distributions by tissue compartment and dosimetry calculations based on the MIRD formalism were performed. Results: We revealed the activity distribution differences across and within patient samples at the macro- and microscopic scales. Microdistribution analysis confirmed localized high-activity regions in a background of low-activity tissue. We evaluated heterogeneous α-particle emission distribution concentrated at bone-tissue interfaces and calculated spatially nonuniform absorbed-dose profiles. Conclusion: Primary patient data of radiopharmaceutical therapy distribution at the small scale revealed that 223Ra uptake is nonuniform. Dose estimates present both opportunities and challenges to enhance patient outcomes and are a first step toward personalized treatment approaches and improved understanding of α-particle radiopharmaceutical therapies.
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Affiliation(s)
- Nadia Benabdallah
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Peng Lu
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Diane S Abou
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Hanwen Zhang
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - David Ulmert
- Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Robert F Hobbs
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, Maryland
| | - Hiram A Gay
- Department of Radiation Oncology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Brian W Simons
- Center for Comparative Medicine, Baylor University, Houston, Texas
| | - Muhammad A Saeed
- Department of Medicine, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Buck E Rogers
- Department of Radiation Oncology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Abhinav K Jha
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Yuan-Chuan Tai
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Christopher D Malone
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Joseph E Ippolito
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Jeff Michalski
- Department of Radiation Oncology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Jack W Jennings
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Brian C Baumann
- Department of Radiation Oncology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
- Department of Radiation Oncology, Springfield Clinic, Springfield, Illinois; and
| | - Russell K Pachynski
- Department of Medicine, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Daniel L J Thorek
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri;
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
- Oncologic Imaging Program, Siteman Cancer Center, Washington University in St. Louis School of Medicine, St. Louis, Missouri
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Klyuzhin IS, Chaussé G, Bloise I, Harsini S, Ferres JL, Uribe C, Rahmim A. PSMA-Hornet: Fully-automated, multi-target segmentation of healthy organs in PSMA PET/CT images. Med Phys 2024; 51:1203-1216. [PMID: 37544015 DOI: 10.1002/mp.16658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 03/28/2023] [Accepted: 05/26/2023] [Indexed: 08/08/2023] Open
Abstract
BACKGROUND Prostate-specific membrane antigen (PSMA) PET imaging represents a valuable source of information reflecting disease stage, response rate, and treatment optimization options, particularly with PSMA radioligand therapy. Quantification of radiopharmaceutical uptake in healthy organs from PSMA images has the potential to minimize toxicity by extrapolation of the radiation dose delivery towards personalization of therapy. However, segmentation and quantification of uptake in organs requires labor-intensive organ delineations that are often not feasible in the clinic nor scalable for large clinical trials. PURPOSE In this work we develop and test the PSMA Healthy organ segmentation network (PSMA-Hornet), a fully-automated deep neural net for simultaneous segmentation of 14 healthy organs representing the normal biodistribution of [18 F]DCFPyL on PET/CT images. We also propose a modified U-net architecture, a self-supervised pre-training method for PET/CT images, a multi-target Dice loss, and multi-target batch balancing to effectively train PSMA-Hornet and similar networks. METHODS The study used manually-segmented [18 F]DCFPyL PET/CT images from 100 subjects, and 526 similar images without segmentations. The unsegmented images were used for self-supervised model pretraining. For supervised training, Monte-Carlo cross-validation was used to evaluate the network performance, with 85 subjects in each trial reserved for model training, 5 for validation, and 10 for testing. Image segmentation and quantification metrics were evaluated on the test folds with respect to manual segmentations by a nuclear medicine physician, and compared to inter-rater agreement. The model's segmentation performance was also evaluated on a separate set of 19 images with high tumor load. RESULTS With our best model, the lowest mean Dice coefficient on the test set was 0.826 for the sublingual gland, and the highest was 0.964 for liver. The highest mean error in tracer uptake quantification was 13.9% in the sublingual gland. Self-supervised pretraining improved training convergence, train-to-test generalization, and segmentation quality. In addition, we found that a multi-target network produced significantly higher segmentation accuracy than single-organ networks. CONCLUSIONS The developed network can be used to automatically obtain high-quality organ segmentations for PSMA image analysis tasks. It can be used to reproducibly extract imaging data, and holds promise for clinical applications such as personalized radiation dosimetry and improved radioligand therapy.
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Affiliation(s)
- Ivan S Klyuzhin
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
- AI for Health, Microsoft, Redmond, Washington, USA
- Deparment of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Guillaume Chaussé
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
| | - Ingrid Bloise
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
| | - Sara Harsini
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
| | | | - Carlos Uribe
- Deparment of Radiology, University of British Columbia, Vancouver, BC, Canada
- Department of Functional Imaging, BC Cancer, Vancouver, BC, Canada
| | - Arman Rahmim
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
- Deparment of Radiology, University of British Columbia, Vancouver, BC, Canada
- Deparment of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
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Oh K, Gallagher KJ, Hyun M, Schott D, Wisnoskie S, Lei Y, Hendley S, Wong J, Wang S, Graff B, Jenkins C, Rutar F, Ahmed M, McNeur J, Taylor J, Schmidt M, Senadheera L, Smith W, Umstadter D, Lele SM, Dai R, Jianghu (James) D, Yan Y, Su‐min Z. Initial experience with an electron FLASH research extension (FLEX) for the Clinac system. J Appl Clin Med Phys 2024; 25:e14159. [PMID: 37735808 PMCID: PMC10860433 DOI: 10.1002/acm2.14159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/04/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
PURPOSE Radiotherapy delivered at ultra-high-dose-rates (≥40 Gy/s), that is, FLASH, has the potential to effectively widen the therapeutic window and considerably improve the care of cancer patients. The underlying mechanism of the FLASH effect is not well understood, and commercial systems capable of delivering such dose rates are scarce. The purpose of this study was to perform the initial acceptance and commissioning tests of an electron FLASH research product for preclinical studies. METHODS A linear accelerator (Clinac 23EX) was modified to include a non-clinical FLASH research extension (the Clinac-FLEX system) by Varian, a Siemens Healthineers company (Palo Alto, CA) capable of delivering a 16 MeV electron beam with FLASH and conventional dose rates. The acceptance, commissioning, and dosimetric characterization of the FLEX system was performed using radiochromic film, optically stimulated luminescent dosimeters, and a plane-parallel ionization chamber. A radiation survey was conducted for which the shielding of the pre-existing vault was deemed sufficient. RESULTS The Clinac-FLEX system is capable of delivering a 16 MeV electron FLASH beam of approximately 1 Gy/pulse at isocenter and reached a maximum dose rate >3.8 Gy/pulse near the upper accessory mount on the linac gantry. The percent depth dose curves of the 16 MeV FLASH and conventional modes for the 10 × 10 cm2 applicator agreed within 0.5 mm at a range of 50% of the maximum dose. Their respective profiles agreed well in terms of flatness but deviated for field sizes >10 × 10 cm2 . The output stability of the FLASH system exhibited a dose deviation of <1%. Preliminary cell studies showed that the FLASH dose rate (180 Gy/s) had much less impact on the cell morphology of 76N breast normal cells compared to the non-FLASH dose rate (18 Gy/s), which induced large-size cells. CONCLUSION Our studies characterized the non-clinical Clinac-FLEX system as a viable solution to conduct FLASH research that could substantially increase access to ultra-high-dose-rate capabilities for scientists.
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Affiliation(s)
- Kyuhak Oh
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Megan Hyun
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Diane Schott
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Yu Lei
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Jeffrey Wong
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Shuo Wang
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Brendan Graff
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Frank Rutar
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Md Ahmed
- Varian Medical SystemsPalo AltoCaliforniaUSA
| | | | | | | | | | - Wendy Smith
- Varian Medical SystemsPalo AltoCaliforniaUSA
| | | | | | - Ran Dai
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Ying Yan
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Zhou Su‐min
- University of Nebraska Medical CenterOmahaNebraskaUSA
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Sechopoulos I, Dance DR, Boone JM, Bosmans HT, Caballo M, Diaz O, van Engen R, Fedon C, Glick SJ, Hernandez AM, Hill ML, Hulme KW, Longo R, Rabin C, Sanderink WBG, Seibert JA. Joint AAPM Task Group 282/EFOMP Working Group Report: Breast dosimetry for standard and contrast-enhanced mammography and breast tomosynthesis. Med Phys 2024; 51:712-739. [PMID: 38018710 DOI: 10.1002/mp.16842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 09/26/2023] [Accepted: 11/10/2023] [Indexed: 11/30/2023] Open
Abstract
Currently, there are multiple breast dosimetry estimation methods for mammography and its variants in use throughout the world. This fact alone introduces uncertainty, since it is often impossible to distinguish which model is internally used by a specific imaging system. In addition, all current models are hampered by various limitations, in terms of overly simplified models of the breast and its composition, as well as simplistic models of the imaging system. Many of these simplifications were necessary, for the most part, due to the need to limit the computational cost of obtaining the required dose conversion coefficients decades ago, when these models were first implemented. With the advancements in computational power, and to address most of the known limitations of previous breast dosimetry methods, a new breast dosimetry method, based on new breast models, has been developed, implemented, and tested. This model, developed jointly by the American Association of Physicists in Medicine and the European Federation for Organizations of Medical Physics, is applicable to standard mammography, digital breast tomosynthesis, and their contrast-enhanced variants. In addition, it includes models of the breast in both the cranio-caudal and the medio-lateral oblique views. Special emphasis was placed on the breast and system models used being based on evidence, either by analysis of large sets of patient data or by performing measurements on imaging devices from a range of manufacturers. Due to the vast number of dose conversion coefficients resulting from the developed model, and the relative complexity of the calculations needed to apply it, a software program has been made available for download or online use, free of charge, to apply the developed breast dosimetry method. The program is available for download or it can be used directly online. A separate User's Guide is provided with the software.
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Affiliation(s)
- Ioannis Sechopoulos
- Radboud University Medical Center, Nijmegen, The Netherlands
- Dutch Expert Centre for Screening (LRCB), Nijmegen, The Netherlands
- University of Twente, Enschede, The Netherlands
| | - David R Dance
- National Co-ordinating Centre for the Physics of Mammography (NCCPM), Royal Surrey County Hospital, Guildford, UK
| | - John M Boone
- University of California, Davis, California, USA
| | | | - Marco Caballo
- Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Ruben van Engen
- Dutch Expert Centre for Screening (LRCB), Nijmegen, The Netherlands
| | - Christian Fedon
- Radboud University Medical Center (now at Nuclear Research and Consultancy Group, NRG), Nijmegen, The Netherlands
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Miles D, Sforza D, Wong J, Rezaee M. Dosimetric characterization of a rotating anode x-ray tube for FLASH radiotherapy research. Med Phys 2024; 51:1474-1483. [PMID: 37458068 PMCID: PMC10792113 DOI: 10.1002/mp.16609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 05/16/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023] Open
Abstract
PURPOSE Most current research toward ultra-high dose rate (FLASH) radiation is conducted with advanced proton and electron accelerators, which are of limited accessibility to basic laboratory research. An economical alternative to charged particle accelerators is to employ high-capacity rotating anode x-ray tubes to produce kilovoltage x-rays at FLASH dose rates at short source-to-surface distances (SSD). This work describes a comprehensive dosimetric evaluation of a rotating anode x-ray tube for potential application in laboratory FLASH study. METHODS AND MATERIALS A commercially available high-capacity fluoroscopy x-ray tube with 75 kW input power was implemented as a potential FLASH irradiator. Radiochromic EBT3 film and thermoluminescent dosimeters (TLDs) were used to investigate the effects of SSD and field size on dose rates and depth-dose characteristics in kV-compatible solid water phantoms. Custom 3D printed accessories were developed to enable reproducible phantom setup at very short SSD. Open and collimated radiation fields were assessed. RESULTS Despite the lower x-ray energy and short SSD used, FLASH dose rates above 40 Gy/s were achieved for targets up to 10-mm depth in solid water. Maximum surface dose rates of 96 Gy/s were measured in the open field at 47 mm SSD. A non-uniform high-to-low dose gradient was observed in the planar dose distribution, characteristic of anode heel effects. With added collimation, beams up to 10-mm diameter with reasonable uniformity can be produced. Typical 80%-20% penumbra in the collimated x-ray FLASH beams were less than 1 mm at 5-mm depth in phantom. Ramp-up times at the maximum input current were less than 1 ms. CONCLUSION Our dosimetric characterization demonstrates that rotating anode x-ray tube technology is capable of producing radiation beams in support of preclinical FLASH radiobiology research.
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Affiliation(s)
- Devin Miles
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, 21231 MD, USA
| | - Daniel Sforza
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, 21231 MD, USA
| | - John Wong
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, 21231 MD, USA
| | - Mohammad Rezaee
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, 21231 MD, USA
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Ahmed M, Bicher S, Combs SE, Lindner R, Raulefs S, Schmid TE, Spasova S, Stolz J, Wilkens JJ, Winter J, Bartzsch S. In Vivo Microbeam Radiation Therapy at a Conventional Small Animal Irradiator. Cancers (Basel) 2024; 16:581. [PMID: 38339332 DOI: 10.3390/cancers16030581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024] Open
Abstract
Microbeam radiation therapy (MRT) is a still pre-clinical form of spatially fractionated radiotherapy, which uses an array of micrometer-wide, planar beams of X-ray radiation. The dose modulation in MRT has proven effective in the treatment of tumors while being well tolerated by normal tissue. Research on understanding the underlying biological mechanisms mostly requires large third-generation synchrotrons. In this study, we aimed to develop a preclinical treatment environment that would allow MRT independent of synchrotrons. We built a compact microbeam setup for pre-clinical experiments within a small animal irradiator and present in vivo MRT application, including treatment planning, dosimetry, and animal positioning. The brain of an immobilized mouse was treated with MRT, excised, and immunohistochemically stained against γH2AX for DNA double-strand breaks. We developed a comprehensive treatment planning system by adjusting an existing dose calculation algorithm to our setup and attaching it to the open-source software 3D-Slicer. Predicted doses in treatment planning agreed within 10% with film dosimetry readings. We demonstrated the feasibility of MRT exposures in vivo at a compact source and showed that the microbeam pattern is observable in histological sections of a mouse brain. The platform developed in this study will be used for pre-clinical research of MRT.
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Affiliation(s)
- Mabroor Ahmed
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Sandra Bicher
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
| | - Stephanie Elisabeth Combs
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
| | - Rainer Lindner
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
| | - Susanne Raulefs
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
| | - Thomas E Schmid
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
| | - Suzana Spasova
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Jessica Stolz
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
| | - Jan Jakob Wilkens
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Johanna Winter
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany
| | - Stefan Bartzsch
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany
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Caccia M, Giaz A, Galoppo M, Santoro R, Martyn M, Bianchi C, Novario R, Woulfe P, O’Keeffe S. Characterisation of a Silicon Photomultiplier Based Oncological Brachytherapy Fibre Dosimeter. Sensors (Basel) 2024; 24:910. [PMID: 38339627 PMCID: PMC10856931 DOI: 10.3390/s24030910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/21/2023] [Accepted: 11/30/2023] [Indexed: 02/12/2024]
Abstract
Source localisation and real-time dose verification are at the forefront of medical research in brachytherapy, an oncological radiotherapy procedure based on radioactive sources implanted in the patient body. The ORIGIN project aims to respond to this medical community's need by targeting the development of a multi-point dose mapping system based on fibre sensors integrating a small volume of scintillating material into the tip and interfaced with silicon photomultipliers operated in counting mode. In this paper, a novel method for the selection of the optimal silicon photomultipliers to be used is presented, as well as a laboratory characterisation based on dosimetric figures of merit. More specifically, a technique exploiting the optical cross-talk to maintain the detector linearity in high-rate conditions is demonstrated. Lastly, it is shown that the ORIGIN system complies with the TG43-U1 protocol in high and low dose rate pre-clinical trials with actual brachytherapy sources, an essential requirement for assessing the proposed system as a dosimeter and comparing the performance of the system prototype against the ORIGIN project specifications.
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Affiliation(s)
- Massimo Caccia
- Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy; (A.G.); (M.G.); (R.S.)
| | - Agnese Giaz
- Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy; (A.G.); (M.G.); (R.S.)
| | - Marco Galoppo
- Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy; (A.G.); (M.G.); (R.S.)
| | - Romualdo Santoro
- Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy; (A.G.); (M.G.); (R.S.)
| | - Micheal Martyn
- Radiotherapy Department, Galway Clinic, Doughiska Road, H91 HHT0 Galway, Ireland;
| | - Carla Bianchi
- Ospedale di Circolo di Varese, Università degli Studi dell’Insubria, Viale Borri, 57, 21100 Varese, Italy; (C.B.); (R.N.); (P.W.)
| | - Raffaele Novario
- Ospedale di Circolo di Varese, Università degli Studi dell’Insubria, Viale Borri, 57, 21100 Varese, Italy; (C.B.); (R.N.); (P.W.)
| | - Peter Woulfe
- Ospedale di Circolo di Varese, Università degli Studi dell’Insubria, Viale Borri, 57, 21100 Varese, Italy; (C.B.); (R.N.); (P.W.)
| | - Sinead O’Keeffe
- Optical Fibre Sensors Research Centre, University of Limerick, V94 T9PX Limerick, Ireland;
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Bui TNH, Large M, Poder J, Bucci J, Bianco E, Giampaolo RA, Rivetti A, Da Rocha Rolo M, Pastuovic Z, Corradino T, Pancheri L, Petasecca M. Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy. Sensors (Basel) 2024; 24:692. [PMID: 38276383 PMCID: PMC10818778 DOI: 10.3390/s24020692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
We assessed the accuracy of a prototype radiation detector with a built in CMOS amplifier for use in dosimetry for high dose rate brachytherapy. The detectors were fabricated on two substrates of epitaxial high resistivity silicon. The radiation detection performance of prototypes has been tested by ion beam induced charge (IBIC) microscopy using a 5.5 MeV alpha particle microbeam. We also carried out the HDR Ir-192 radiation source tracking at different depths and angular dose dependence in a water equivalent phantom. The detectors show sensitivities spanning from (5.8 ± 0.021) × 10-8 to (3.6 ± 0.14) × 10-8 nC Gy-1 mCi-1 mm-2. The depth variation of the dose is within 5% with that calculated by TG-43. Higher discrepancies are recorded for 2 mm and 7 mm depths due to the scattering of secondary particles and the perturbation of the radiation field induced in the ceramic/golden package. Dwell positions and dwell time are reconstructed within ±1 mm and 20 ms, respectively. The prototype detectors provide an unprecedented sensitivity thanks to its monolithic amplification stage. Future investigation of this technology will include the optimisation of the packaging technique.
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Affiliation(s)
- Thi Ngoc Hang Bui
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; (T.N.H.B.); (M.L.); (J.P.); (J.B.)
| | - Matthew Large
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; (T.N.H.B.); (M.L.); (J.P.); (J.B.)
| | - Joel Poder
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; (T.N.H.B.); (M.L.); (J.P.); (J.B.)
- St George Cancer Care Centre, Kogarah, NSW 2217, Australia
- School of Physics, University of Sydney, Camperdown, NSW 2050, Australia
| | - Joseph Bucci
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; (T.N.H.B.); (M.L.); (J.P.); (J.B.)
- St George Cancer Care Centre, Kogarah, NSW 2217, Australia
| | - Edoardo Bianco
- Department of Electronics and Telecommunications, Polytechnic University of Turin, 10129 Turin, Italy; (E.B.); (R.A.G.)
- Istituto Nazionale di Fisica Nucleare—Section of Turin, 10125 Turin, Italy; (A.R.); (M.D.R.R.)
| | - Raffaele Aaron Giampaolo
- Department of Electronics and Telecommunications, Polytechnic University of Turin, 10129 Turin, Italy; (E.B.); (R.A.G.)
- Istituto Nazionale di Fisica Nucleare—Section of Turin, 10125 Turin, Italy; (A.R.); (M.D.R.R.)
| | - Angelo Rivetti
- Istituto Nazionale di Fisica Nucleare—Section of Turin, 10125 Turin, Italy; (A.R.); (M.D.R.R.)
| | - Manuel Da Rocha Rolo
- Istituto Nazionale di Fisica Nucleare—Section of Turin, 10125 Turin, Italy; (A.R.); (M.D.R.R.)
| | - Zeljko Pastuovic
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia;
| | - Thomas Corradino
- Department of Industrial Engineering, University of Trento, 38123 Trento, Italy (L.P.)
- Trento Institute for Fundamental Physics and Applications, Istituto Nazionale di Fisica Nucleare, 38123 Trento, Italy
| | - Lucio Pancheri
- Department of Industrial Engineering, University of Trento, 38123 Trento, Italy (L.P.)
- Trento Institute for Fundamental Physics and Applications, Istituto Nazionale di Fisica Nucleare, 38123 Trento, Italy
| | - Marco Petasecca
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; (T.N.H.B.); (M.L.); (J.P.); (J.B.)
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Ohtaki M, Otani K, Yasuda H. Contribution of radioactive particles to the post-explosion exposure of atomic bomb survivors implied from their stable chromosome aberration rates. Front Public Health 2024; 12:1335097. [PMID: 38299079 PMCID: PMC10827992 DOI: 10.3389/fpubh.2024.1335097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/03/2024] [Indexed: 02/02/2024] Open
Abstract
Even today when nearly 80 years have passed after the atomic bomb (A-bomb) was dropped, there are still debates about the exact doses received by the A-bomb survivors. While initial airborne kerma radiation (or energy spectrum of emitted radiation) can be measured with sufficient accuracy to assess the radiation dose to A-bomb survivors, it is not easy to accurately assess the neutron dose including appropriate weighting of neutron absorbed dose. Particularly, possible post-explosion exposure due to the radioactive particles generated through neutron activation have been almost neglected so far, mainly because of a large uncertainty associated to the behavior of those particles. However, it has been supposed that contribution of such non-initial radiation exposure from the neutron-induced radioactive particles could be significant, according to the findings that the stable chromosomal aberration rates which indicate average whole-body radiation doses were found to be more than 30% higher for those exposed indoors than for those outdoors even at the same initial dose estimated for the Life Span Study. In this Mini Review article, the authors explain that such apparently controversial observations can be reasonably explained by assuming a higher production rate of neutron-induced radioactive particles in the indoor environment near the hypocenter.
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Affiliation(s)
- Megu Ohtaki
- Emeritus, The Center for Peace, Hiroshima University, Hiroshima, Japan
- The Center for Peace, Hiroshima University, Hiroshima, Japan
| | - Keiko Otani
- The Center for Peace, Hiroshima University, Hiroshima, Japan
| | - Hiroshi Yasuda
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
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Tronchin S, Forster J, Hickson K, Bezak E. Modeling the effect of daughter migration on dosimetry estimates for unlabeled actinium-225. Med Phys 2024. [PMID: 38197481 DOI: 10.1002/mp.16917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 12/05/2023] [Accepted: 12/13/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND Actinium-225 (225 Ac) is an alpha emitting radionuclide which has demonstrated promising results in Targeted Alpha Therapy (TAT). A concern with 225 Ac is that the decay energy can break the bond to the targeting vehicle, resulting in the release of free alpha-emitting daughter radionuclides in the body. PURPOSE The aim of this work is to develop a compartment model to describe the movement of unlabeled 225 Ac in a human where the daughter isotopes of 225 Ac have unique biokinetics. METHOD The ICRP Occupational Intake of Radionuclides reports were used to construct a compartment model for the 225 Ac decay chain where the daughter isotopes of 225 Ac are assigned their own unique transfer coefficients (TCs) between compartments. Computer simulations were performed for unlabeled 225 Ac uniformly placed in the plasma and only the dose from alpha particles was considered. Absorbed doses to normal organs were determined for the liver, kidneys, bone, soft tissue, active marrow, and blood. Simulations were performed for the case when: (1) the daughters have unique biokinetics and (2) the daughters decay at the site of 225 Ac. RESULTS When the daughters have unique biokinetics, the organs that receive the highest absorbed dose are the liver (male: 1466.6 mGy/MBq, female: 1885.7 mGy/MBq), bone (male: 293.6 mGy/MBq, female: 403.6 mGy/MBq) and kidneys (male: 260.8 mGy/MBq, female: 294.0 mGy/MBq). These doses were compared to the case when the daughters of 225 Ac decay at the site of 225 Ac. There was a 13.5% increase in kidney dose, a 0.8% decrease in liver dose, and <0.1% decrease in bone dose calculations when the daughters have unique biokinetics compared to assuming the daughters decay at the site of 225 Ac. CONCLUSIONS The kidneys received a large dose estimate (260-295 mGy/MBq) as well as a considerable change in dose of +13.5% when the daughters have unique biokinetics compared to assuming the daughters decay at the site of 225 Ac. Therefore, to accurately determine the kidney dose from unlabeled 225 Ac in a human, the biokinetics of the daughter isotopes should be considered.
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Affiliation(s)
- Stephen Tronchin
- Department of Physics, The University of Adelaide, Adelaide, South Australia, Australia
| | - Jake Forster
- Department of Physics, The University of Adelaide, Adelaide, South Australia, Australia
- Medical Physics & Radiation Safety, South Australia Medical Imaging, Adelaide, South Australia, Australia
| | - Kevin Hickson
- Medical Physics & Radiation Safety, South Australia Medical Imaging, Adelaide, South Australia, Australia
- Allied Health & Human Performance, University of South Australia, Adelaide, South Australia, Australia
| | - Eva Bezak
- Department of Physics, The University of Adelaide, Adelaide, South Australia, Australia
- Allied Health & Human Performance, University of South Australia, Adelaide, South Australia, Australia
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Khan AU, Radtke J, DeWerd L. Characterization of a segmented printed circuit board (PCB) as a standard for absorbed dose to water from alpha-emitting radionuclides. Med Phys 2024. [PMID: 38194496 DOI: 10.1002/mp.16940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/31/2023] [Accepted: 12/31/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND Our previous work introduced and evaluated a standard for surface absorbed dose rate per unit radioactivity to water from unsealed alpha-emitting radionuclides used in targeted radionuclide therapy (TRT). An overall uncertainty over 4.0% at k = 1 was reported for the absorbed dose to air measurements, which was partially attributed to the rotational alignment uncertainty in the geometrical setup. PURPOSE A printed circuit board (PCB) with a segmented guard was constructed to align the extrapolation chamber (EC) and the source plates using a differential capacitance technique. The PCB EC aimed to enhance the repeatability of the ionization current measurements. The PCB EC was evaluated using a thin film 210 Po source. The measured absorbed dose to air cavity was compared with the Monte Carlo (MC) calculations. Using the extrapolation method, the surface absorbed dose rate to water was calculated. METHODS The PCB EC was constructed with a 4.50 mm diameter collector surrounded by four sectors and a guard electrode. The sectors were isolated for rotational alignment and later connected to the guard for ionization current measurements. A bridge circuit measured differential capacitance between opposing sectors, and a hexapod motion stage rotated the source substrate to minimize the differential capacitance. The EC was evaluated using a 210 Po source with a 3.20 mm diameter and 1.253 μCi radioactivity. MC simulations were performed to calculate thek p o i n t ${k}_{point}$ ,k b a c k s c a t t e r ${k}_{backscatter}$ , andk d i v ${k}_{div}$ correction factors. Ionization current measurements were performed for air gaps in the 0.3-0.525 mm range and surface absorbed dose rate to water was calculated. RESULTS Rotational offsets of up to 3.0° were found and the current repeatability was found to increase with the absorbed dose to air uncertainty calculated to be ∼2.0%. Using the capacitance method, the effective EC diameter was measured to be 4.53 mm. The recombination, polarity, and electrometer corrections were reported to be within 1.00% across all measurement trials. The MC-calculated correction factors were calculated to be much larger than the recombination and polarity correction factors. The averagek p o i n t ${k}_{point}$ ,k b a c k s c a t t e r ${k}_{backscatter}$ , andk d i v ${k}_{div}$ corrections were calculated to be 1.063, 0.9402, and 2.136, respectively. The MC-calculated absorbed dose to air was found to overestimate the absorbed dose by over 4.00% when compared with the measured absorbed dose to air. The surface absorbed dose rate to water was calculated to be2.304 × 10 - 6 $2.304 \times {10}^{ - 6}$ Gy/s/Bq with an overall uncertainty of 4.07%. CONCLUSIONS The constructed PCB EC was deemed suitable as an absorbed dose standard. A repeatable rotational alignment was achieved using the differential capacitance technique. The metal electrodes on the PCB made a difference of < 1.00% on the backscatter correction when compared to the EC comprised of polystyrene-equivalent collector. A 20% difference in the surface absorbed dose rate to water was found between the two ECs, which is attributed to the cavity diameter differences leading to different magnitudes of dose fall-off along the lateral direction.
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Affiliation(s)
- Ahtesham Ullah Khan
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jeff Radtke
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Larry DeWerd
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Lang X, Hu Z, Zhao Z, Zhou K, Xu Z, Li M, Mao R, Luo F, Huang C, Kang X, Li J, Liu X, Zhou L, Xiao G. Preliminary study of low-pressure ionization chamber for online dose monitoring in FLASH carbon ion radiotherapy. Phys Med Biol 2024; 69:025008. [PMID: 38064745 DOI: 10.1088/1361-6560/ad13d0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/08/2023] [Indexed: 01/09/2024]
Abstract
The FLASH effect of carbon ion therapy has recently attracted significant attention from the scientific community. However, the radiobiological mechanism of the effect and the exact therapeutic conditions are still under investigation. Therefore, the dosimetry accuracy is critical for testing hypotheses about the effect and quantifying FLASH Radiotherapy. In this paper, the FLASH ionization chamber at low-pressure was designed, and its dose rate dependence was verified with the Faraday cup. In addition, the dose response was tested under the air pressure of the ionization chamber of 10 mbar, 80 mbar and 845 mbar, respectively. The results showed that when the pressure was 10 mbar, the dose linearity was verified and calibrated at the dose rate of ∼50 Gy s-1, and the residuals were less than 2%. In conclusion, the FLASH ionization chamber is a promising instrument for online dose monitoring.
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Affiliation(s)
- Xinle Lang
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
- University of Chinese Academy of Sciences, School of Nuclear Science and Technology, Beijing 100049, People's Republic of China
| | - Zhengguo Hu
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
- University of Chinese Academy of Sciences, School of Nuclear Science and Technology, Beijing 100049, People's Republic of China
| | - Zulong Zhao
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Kai Zhou
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Zhiguo Xu
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Min Li
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Ruishi Mao
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
- University of Chinese Academy of Sciences, School of Nuclear Science and Technology, Beijing 100049, People's Republic of China
| | - Faming Luo
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
- University of Chinese Academy of Sciences, School of Nuclear Science and Technology, Beijing 100049, People's Republic of China
| | - Chuan Huang
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China
| | - Xincai Kang
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Juan Li
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Xiaotao Liu
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Libin Zhou
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
| | - Guoqing Xiao
- Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou 730000, Gansu, People's Republic of China
- University of Chinese Academy of Sciences, School of Nuclear Science and Technology, Beijing 100049, People's Republic of China
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Chalewska W, Cegla P, Moczulska A, Strzemecka E, Sackiewicz A, Dedecjus M. Dosimetry during iodine-131 therapy - a technical point of view from a single centre's own experience. Nucl Med Rev Cent East Eur 2024; 27:1-5. [PMID: 38529769 DOI: 10.5603/nmr.98772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 01/07/2024] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND Nuclear medicine uses radionuclides in medicine for diagnosis, staging, therapy, and monitoring the response to therapy. The application of radiopharmaceutical therapy for the treatment of certain diseases is well-established, and the field is expanding. Internal dosimetry is multifaceted and includes different workflows, as well as various calculations based on patient- specific dosimetry. AIM The objective of this study was to introduce the technical issues which might occur during iodine-131 (¹³¹I) dosimetry performed in nuclear medicine departments. MATERIAL AND METHODS Retrospective analysis was performed on a group of 44 patients with papillary thyroid cancer who between May 2021 and October 2021 underwent a 131I treatment: 80-100 mCi (2200-3700 MBq, based on the previous medical history and stage of the disease). Patients underwent a series of ¹³¹I therapy scans using gamma camera Discovery NM 670 CT. Whole body scan (WBS) was performed 2, 4, 24 and 48 hours after ¹³¹I administration. Additionally, after 24 hours of single photon emission computed tomography/ computed tomography, two fields of view (SPECT/CT 2-FOV) were performed from the mid-head to the bladder. RESULTS During the dosimetry procedure, several issues arise. Firstly, after receiving therapeutic doses of ¹³¹I, patients should remain in their rooms until the appropriate activity is achieved before being transported to the diagnostic room. Secondly, the walls between examination rooms meet the requirements for accurate diagnosis but not for therapy, leading to the occurrence of artefacts in patients examined behind the wall, potentially influencing the examination results. Thirdly, personnel in the control room also experience additional exposure (10 times greater than in the case of standard diagnostic procedure). CONCLUSIONS The dosimetry in patients in whom therapeutic procedures are performed with the use of isotopes is mandatory according to Polish and European law, technical issues which occur during the dosimetry procedures might influence the organization of the work in departments.
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Affiliation(s)
- Wioletta Chalewska
- Department of Endocrine Oncology and Nuclear Medicine, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | - Paulina Cegla
- Department of Endocrine Oncology and Nuclear Medicine, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland.
| | - Anna Moczulska
- Department of Endocrine Oncology and Nuclear Medicine, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | - Edyta Strzemecka
- Department of Endocrine Oncology and Nuclear Medicine, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | - Agata Sackiewicz
- Department of Endocrine Oncology and Nuclear Medicine, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | - Marek Dedecjus
- Department of Endocrine Oncology and Nuclear Medicine, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
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Haldar S, Sarkar B, Dixit A. Dose to Organ at Risk and its Characteristic Variation with the Clinically Used Different Prescription Levels for Early-stage Left-sided Breast Cancer. Clin Oncol (R Coll Radiol) 2024; 36:21-29. [PMID: 38040550 DOI: 10.1016/j.clon.2023.11.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 05/27/2023] [Accepted: 11/22/2023] [Indexed: 12/03/2023]
Abstract
AIMS To evaluate the organ at risk (OAR) dose and its characteristic variation with different clinically usable prescription doses (RxD) for breast and chest wall radiotherapy in patients with early-stage left-sided breast cancer. MATERIALS AND METHODS In total, 145 patients with early-stage breast cancers (T1N0M0-T2N0M0) on the left side were treated with radiotherapy after a modified radical mastectomy or breast conservation surgery, with a mean age of 45.1 ± 21.6 years. The patient received 4050 cGy of field-in-field (three-dimensional conformal radiotherapy) treatment limited to the breast or chest wall, excluding the supraclavicular node, axillary node and internal mammary chain, over 15 fractions. Additional plans of 5000 cGy/25 fractions, 4500 cGy/20 fractions and 2600 cGy/5 fractions were created with no or minor changes to the original plan. Mathematical modelling was used to study the distinctive change in the dose-volume characteristics for various OARs as a function of the RxD. OAR dosages, both absolute and normalised, were expressed in terms of the RxD. The mathematical (functional) relationship between OAR doses and different prescription levels was deduced by the least squares fit method. RESULT The left lung mean dose, V5Gy (%), V10Gy (%) and V20Gy (%) and the heart mean dose, V10Gy (%) and V20Gy (%) were evaluated. The dose-volume parameters showed a parabolic variation (x2) with the RxD. Prescription normalised OAR doses showed a linear relationship with the RxD; relative dose increased with diminishing RxD. Normalised lung and heart mean doses exhibited saturation (linear relationship) with RxD variation. Paired sample t-test results between RxD versus all evaluated parameters were found to be statistically significant (P = 0.004). The Pearson correlation coefficient between different prescription levels for left lung mean dose (range 0.942-1.0), heart mean dose (range 1.0-1.0), left lung V5Gy (%) (range 0.987-1.0), left lung V10Gy (%) (range 0.991-0.999), heart V10Gy (%) (range 0.998-1.0). CONCLUSION The functional form of absolute OAR dose-volume parameters versus RxD is parabolic and the RxD normalised OAR dose-volume parameter versus RxD is a straight line with a negative slope as RxD increases. This indicates an increase in the relative OAR dose-volume parameters if the RxD is reduced. This study is the first of its kind to compare the OAR doses as a function of clinically used degenerate prescription levels. These data will help to comprehend the OAR doses while adopting a new dose fractionation regimen and reviewing the radiotherapy treatment plans.
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Affiliation(s)
- S Haldar
- Department of Radiation Oncology, Saroj Gupta Cancer Centre and Research Institute, Kolkata, India; Department of Physics, Institute of Applied Science and Humanities, GLA University, Mathura, India
| | - B Sarkar
- Department of Radiation Oncology, Apollo Multispeciality Hospital, Kolkata, India.
| | - A Dixit
- Department of Mathematics, Institute of Applied Science and Humanities, GLA University, Mathura, India
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Degda N, Patel N, Verma V, Murthy KVR, Srinivas M. Luminescence and dosimetry approach in terbium(III)-activated tungstate double perovskite. LUMINESCENCE 2024; 39:e4622. [PMID: 37950516 DOI: 10.1002/bio.4622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/18/2023] [Indexed: 11/12/2023]
Abstract
A series of tungstate double perovskite Ca3 WO6 doped with Tb3+ was prepared by a combustion process using urea as a flux. The crystal structure identification of Ca3 WO6 :Tb3+ phosphors was done using X-ray diffraction patterns, and a monoclinic structure was discovered. The Fourier transform infrared spectrum of Ca3 WO6 :Tb3+ displayed characteristic vibrations of tungstate bonds. Under 278 nm excitation, Ca3 WO6 :Tb3+ exhibited intense downconversion green emission, which corresponded to the 5 D4 -7 FJ (J = 4,5) transitions of Tb3+ . The phosphor exhibited the highest photoluminescence (PL) intensity when it was doped with 1 mol% of Tb3+ ; later intensity quenching appeared to be due to the multipolar interaction at higher dopant concentrations. Moreover, high-quality thermoluminescence (TL) was detected when phosphors were irradiated using beta rays. The effects of Tb3+ concentration and beta dose on TL intensity were the two major aspects studied in detail. The TL intensity demonstrated excellent linear response to the applied range of beta dose. The trap parameters of the studied phosphors were computed by the peak shape approach and glow curve deconvolution. The fading effect on TL intensity was studied by recording the TL glow curves after 1 month of beta irradiation. Obtained results from the PL and TL characterizations showed that the phosphors under study have the potential to be used in lighting displays and in thermoluminescence dosimetry.
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Affiliation(s)
- Naresh Degda
- Luminescence Materials Laboratory, Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, India
| | - Nimesh Patel
- Luminescence Materials Laboratory, Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, India
| | - Vishwnath Verma
- Luminescence Materials Laboratory, Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, India
| | - Kota Venkata Ramana Murthy
- Display Materials Laboratory, Applied Physics Department, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara, India
| | - Mangalampalli Srinivas
- Luminescence Materials Laboratory, Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, India
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Onal C, Efe E, Bozca R, Yavas C, Yavas G, Arslan G. The impact of margin reduction on radiation dose distribution of ultra-hypofractionated prostate radiotherapy utilizing a 1.5-T MR-Linac. J Appl Clin Med Phys 2024; 25:e14179. [PMID: 38013636 PMCID: PMC10795449 DOI: 10.1002/acm2.14179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND We examined the effects of reducing the planning target volume (PTV) margin in MR-guided radiotherapy (MRgRT) on the distribution of radiation dose to target volumes and organs-at-risk (OARs). Thus, we compared MR-Linac (MRL) plans with and without reduced margin and intensity-modulated radiotherapy (IMRT) plan with conventional linac for low-risk prostate cancer patients receiving 36.25 Gy in five fractions of ultra-hypofractionated radiation therapy. MATERIALS AND METHODS Twenty low-risk prostate cancer patients treated with 1.5 T MR-Linac were evaluated. The same planning CT images were used for four plans: the MRL-R plan with reduced margin planning target volume (PTV-R) and the MRL-N plan with normal margin PTV (PTV-N), which is also used for IMRT plan. In four plans, PTV doses, organs-at-risk (OARs) doses, the homogeneity index (HI), and monitor units were compared. RESULTS All plans met the criteria for PTV coverage and OARs dose constraints. The maximum and mean PTV doses were significantly higher in the MRL-R and MRL-N plans compared to the IMRT plan. The HI was lowest in the IMRT plan (0.040 ± 0.013) and highest in the MRL-N plan (0.055 ± 0.012; p < 0.001). There was no significant difference in the PTV dosimetric parameters between the MRL-R and the MRL-N plans. The high doses in the rectum was significantly lower in the MRL-R compared to other plans. The bladder V36.25 Gy was significantly lower in the MRL-R plan (2.43 ± 1.87 Gy) compared to MRL-N (4.50 ± 2.42 Gy; p < 0.001), and IMRT plans (4.76 ± 2.77 Gy; p < 0.001). There was no significant difference in the low-dose volumes of the body, maximum femur doses, or monitor units across each plan. CONCLUSIONS Ultra-hypofractionated MR-guided RT with 1.5 T MRL is dosimetrically feasible for patients with prostate cancer. The improved soft tissue contrast and the online adaptive plan for 1.5 T MR-Linac allows for PTV margin reduction resulted in a significant dose reduction in OARs.
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Affiliation(s)
- Cem Onal
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
- Adana Dr. Turgut Noyan Research and Treatment CenterDepartment of Radiation OncologyBaskent University Faculty of MedicineAdanaTurkey
| | - Esma Efe
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
| | - Recep Bozca
- Adana Dr. Turgut Noyan Research and Treatment CenterDepartment of Radiation OncologyBaskent University Faculty of MedicineAdanaTurkey
| | - Cagdas Yavas
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
| | - Guler Yavas
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
| | - Gungor Arslan
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
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Liu K, Holmes S, Hooten B, Schüler E, Beddar S. Evaluation of ion chamber response for applications in electron FLASH radiotherapy. Med Phys 2024; 51:494-508. [PMID: 37696271 PMCID: PMC10840726 DOI: 10.1002/mp.16726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 08/08/2023] [Accepted: 08/23/2023] [Indexed: 09/13/2023] Open
Abstract
Ion chambers are required for calibration and reference dosimetry applications in radiation therapy (RT). However, exposure of ion chambers in ultra-high dose rate (UHDR) conditions pertinent to FLASH-RT leads to severe saturation and ion recombination, which limits their performance and usability. The purpose of this study was to comprehensively evaluate a set of commonly used commercially available ion chambers in RT, all with different design characteristics, and use this information to produce a prototype ion chamber with improved performance in UHDR conditions as a first step toward ion chambers specific for FLASH-RT. The Advanced Markus and Exradin A10, A26, and A20 ion chambers were evaluated. The chambers were placed in a water tank, at a depth of 2 cm, and exposed to an UHDR electron beam at different pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings on an IntraOp Mobetron. Ion chamber responses were investigated for the various beam parameter settings to isolate their dependence on integrated dose, mean dose rate and instantaneous dose rate, dose-per-pulse (DPP), and their design features such as chamber type, bias voltage, and collection volume. Furthermore, a thin parallel-plate (TPP) prototype ion chamber with reduced collector plate separation and volume was constructed and equally evaluated as the other chambers. The charge collection efficiency of the investigated ion chambers decreased with increasing DPP, whereas the mean dose rate did not affect the response of the chambers (± 1%). The dependence of the chamber response on DPP was found to be solely related to the total dose within the pulse, and not on mean dose rate, PW, or instantaneous dose rate within the ranges investigated. The polarity correction factor (Ppol ) values of the TPP prototype, A10, and Advanced Markus chambers were found to be independent of DPP and dose rate (± 2%), while the A20 and A26 chambers yielded significantly larger variations and dependencies under the same conditions. Ion chamber performance evaluated under different irradiation conditions of an UHDR electron beam revealed a strong dependence on DPP and a negligible dependence on the mean and instantaneous dose rates. These results suggest that modifications to ion chambers design to improve their usability in UHDR beamlines should focus on minimizing DPP effects, with emphasis on optimizing the electric field strength, through the construction of smaller electrode separation and larger bias voltages. This was confirmed through the production and evaluation of a prototype ion chamber specifically designed with these characteristics.
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Affiliation(s)
- Kevin Liu
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | | | | | - Emil Schüler
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | - Sam Beddar
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
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Chen XM, Xu CD, Zeng LP, Huang XT, Chen AQ, Liu L, Lin LW, Jia LC, Li H, Jiang XB. Analysis of Individualized Silicone Rubber Bolus Using Fan Beam Computed Tomography in Postmastectomy Radiotherapy: A Dosimetric Evaluation and Skin Acute Radiation Dermatitis Survey. Technol Cancer Res Treat 2024; 23:15330338241229367. [PMID: 38297814 PMCID: PMC10832424 DOI: 10.1177/15330338241229367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/28/2023] [Accepted: 01/03/2024] [Indexed: 02/02/2024] Open
Abstract
Objective: To investigate the dosimetric effects of using individualized silicone rubber (SR) bolus on the target area and organs at risk (OARs) during postmastectomy radiotherapy (PMRT), as well as evaluate skin acute radiation dermatitis (ARD). Methods: A retrospective study was performed on 30 patients with breast cancer. Each patient was prepared with an individualized SR bolus of 3 mm thickness. Fan-beam computed tomography (FBCT) was performed at the first and second fractions, and then once a week for a total of 5 times. Dosimetric metrics such as homogeneity index (HI), conformity index (CI), skin dose (SD), and OARs including the heart, lungs, and spinal cord were compared between the original plan and the FBCTs. The acute side effects were recorded. Results: In targets' dosimetric metrics, there were no significant differences in Dmean and V105% between planning computed tomography (CT) and actual treatments (P > .05), while the differences in D95%, V95%, HI, and CI were statistically significant (P < .05). In OARs, there were no significant differences between the Dmean, V5, and V20 of the affected lung, V5 of the heart and Dmax of the spinal cord (P > .05) except the V30 of affected lung, which was slightly lower than the planning CT (P < .05). In SD, both Dmax and Dmean in actual treatments were increased than plan A, and the difference was statistically significant (P < .05), while the skin-V20 and skin-V30 has no difference. Among the 30 patients, only one patient had no skin ARD, and 5 patients developed ARD of grade 2, while the remaining 24 patients were grade 1. Conclusion: The OR bolus showed good anastomoses and high interfraction reproducibility with the chest wall, and did not cause deformation during irradiation. It ensured accurate dose delivery of the target and OARs during the treatment, which may increase SD by over 101%. In this study, no cases of grade 3 skin ARD were observed. However, the potential of using OR bolus to reduce grade 1 and 2 skin ARD warrants further investigation with a larger sample size.
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Affiliation(s)
- Xue-mei Chen
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Chen-di Xu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Li-ping Zeng
- Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong Province, P.R. China
| | - Xiao-tong Huang
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Ao-qiang Chen
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Lu Liu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Liu-wen Lin
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Le-cheng Jia
- Shenzhen United Imaging Research Institute of Innovative Medical Equipment, Shenzhen, Guangdong Province, P.R. China
| | - Hua Li
- Shenzhen United Imaging Research Institute of Innovative Medical Equipment, Shenzhen, Guangdong Province, P.R. China
| | - Xiao-bo Jiang
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
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