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Chermat R, Refet-Mollof E, Kamio Y, Carrier JF, Wong P, Gervais T. Brachytherapy on-a-chip: a clinically-relevant approach for radiotherapy testing in 3d biology. LAB ON A CHIP 2024; 24:2335-2346. [PMID: 38568477 DOI: 10.1039/d4lc00032c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
We describe the first microfluidic device for in vitro testing of brachytherapy (BT), with applications in translational cancer research. Our PDMS-made BT-on-chip system allows highly precise manual insertion of clinical BT seeds, reliable dose calculation using standard clinically-used TG-43 formalism and easy culture of naturally hypoxic spheroids in less than 3 days, thereby increasing the translational potential of the device. As the BT-on-chip platform is designed to be versatile, we showcase three different gold-standard post-irradiation bioassays and recapitulate, for the first time on-chip, key clinical observations such as dose rate effect and hypoxia-induced radioresistance. Our results suggest that BT-on-chip can be used to safely and efficiently integrate BT and radiotherapy to translational research and drug development pipelines, without expensive equipment or complex workflows.
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Affiliation(s)
- Rodin Chermat
- μFO Lab, Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, Canada.
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
- Institut du Cancer de Montréal (ICM), Montréal, Canada
| | - Elena Refet-Mollof
- μFO Lab, Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, Canada.
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
- Institut du Cancer de Montréal (ICM), Montréal, Canada
| | - Yuji Kamio
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
- Département de radio-oncologie, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Canada
| | - Jean-François Carrier
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
- Institut du Cancer de Montréal (ICM), Montréal, Canada
- Département de radio-oncologie, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Canada
- Département de Physique, Université de Montréal, Canada
| | - Philip Wong
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Thomas Gervais
- μFO Lab, Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, Canada.
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
- Institut du Cancer de Montréal (ICM), Montréal, Canada
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Kopačin V, Brkić H, Ivković A, Kasabašić M, Knežević Ž, Majer M, Nodilo M, Turk T, Faj D. Development and validation of the low-cost pregnant female physical phantom for fetal dosimetry in MV photon radiotherapy. J Appl Clin Med Phys 2024; 25:e14240. [PMID: 38150580 PMCID: PMC10860449 DOI: 10.1002/acm2.14240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/27/2023] [Accepted: 11/27/2023] [Indexed: 12/29/2023] Open
Abstract
BACKGROUND Monte Carlo (MC) simulations or measurements in anthropomorphic phantoms are recommended for estimating fetal dose in pregnant patients in radiotherapy. Among the many existing phantoms, there is no commercially available physical phantom representing the entire pregnant woman. PURPOSE In this study, the development of a low-cost, physical pregnant female phantom was demonstrated using commercially available materials. This phantom is based on the previously published computational phantom. METHODS Three tissue substitution materials (soft tissue, lung and bone tissue substitution) were developed. To verify Tena's substitution tissue materials, their radiation properties were assessed and compared to ICRP and ICRU materials using MC simulations in MV radiotherapy beams. Validation of the physical phantom was performed by comparing fetal doses obtained by measurements in the phantom with fetal doses obtained by MC simulations in computational phantom, during an MV photon breast radiotherapy treatment. RESULTS Materials used for building Tena phantom are matched to ICRU materials using physical density, radiation absorption properties and effective atomic number. MC simulations showed that percentage depth doses of Tena and ICRU material comply within 5% for soft and lung tissue, up to 25 cm depth. In the bone tissue, the discrepancy is higher, but again within 5% up to the depth of 5 cm. When the phantom was used for fetal dose measurements in MV photon breast radiotherapy, measured fetal doses complied with fetal doses calculated using MC simulation within 15%. CONCLUSIONS Physical anthropomorphic phantom of pregnant patient can be manufactured using commercial materials and with low expenses. The files needed for 3D printing are now freely available. This enables further studies and comparison of numerical and physical experiments in diagnostic radiology or radiotherapy.
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Affiliation(s)
- Vjekoslav Kopačin
- Faculty of MedicineDepartment of RadiologyJ. J. Strossmayer University Osijek, University Hospital Center OsijekDepartment of Diagnostic and Interventional RadiologyOsijekCroatia
| | - Hrvoje Brkić
- Faculty of MedicineDepartment of Biophysics and Medical PhysicsJ. J. Strossmayer University OsijekOsijekCroatia
- Faculty of Dental Medicine and HealthDepartment of BiophysicsBiology and ChemistryJ. J. Strossmayer University OsijekOsijekCroatia
| | - Ana Ivković
- Faculty of MedicineDepartment of Biophysics and Medical PhysicsJ. J. Strossmayer University Osijek, University Hospital Center OsijekDepartment of Medical PhysicsOsijekCroatia
| | - Mladen Kasabašić
- Faculty of MedicineDepartment of Biophysics and Medical PhysicsJ. J. Strossmayer University Osijek, University Hospital Center OsijekDepartment of Medical PhysicsOsijekCroatia
| | - Željka Knežević
- Division of Materials ChemistryRuđer Bošković InstituteZagrebCroatia
| | - Marija Majer
- Division of Materials ChemistryRuđer Bošković InstituteZagrebCroatia
| | - Marijana Nodilo
- Division of Materials ChemistryRuđer Bošković InstituteZagrebCroatia
| | - Tajana Turk
- Faculty of MedicineDepartment of RadiologyJ. J. Strossmayer University Osijek, University Hospital Center OsijekDepartment of Diagnostic and Interventional RadiologyOsijekCroatia
| | - Dario Faj
- Faculty of MedicineDepartment of Biophysics and Medical PhysicsJ. J. Strossmayer University OsijekOsijekCroatia
- Faculty of Dental Medicine and HealthDepartment of BiophysicsBiology and ChemistryJ. J. Strossmayer University OsijekOsijekCroatia
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Marot M, Jäger F, Greilich S, Karger CP, Jäkel O, Burigo LN. Monte Carlo simulation for proton dosimetry in magnetic fields: Fano test and magnetic field correction factors kBfor Farmer-type ionization chambers. Phys Med Biol 2023; 68:175037. [PMID: 37567226 DOI: 10.1088/1361-6560/acefa1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/10/2023] [Indexed: 08/13/2023]
Abstract
Objective. In this contribution we present a special Fano test for charged particles in presence of magnetic fields in the MC code TOol for PArticle Simulation (TOPAS), as well as the determination of magnetic field correction factorskBfor Farmer-type ionization chambers using proton beams.Approach. Customized C++ extensions for TOPAS were implemented to model the special Fano tests in presence of magnetic fields for electrons and protons. The Geant4-specific transport parameters,DRoverRandfinalRange,were investigated to optimize passing rate and computation time. ThekBwas determined for the Farmer-type PTW 30013 ionization chamber, and 5 custom built ionization chambers with same geometry but varying inner radius, testing magnetic flux density ranging from 0 to 1.0 T and two proton beam energies of 157.43 and 221.05 MeV.Main results. Using the investigated parameters, TOPAS passed the Fano test within 0.39 ± 0.15% and 0.82 ± 0.42%, respectively for electrons and protons. The chamber response (kB,M,Q) gives a maximum at different magnetic flux densities depending of the chamber size, 1.0043 at 1.0 T for the smallest chamber and 1.0051 at 0.2 T for the largest chamber. The local dose differencecBremained ≤ 0.1% for both tested energies. The magnetic field correction factorkB, for the chamber PTW 30013, varied from 0.9946 to 1.0036 for both tested energies.Significance. The developed extension for the special Fano test in TOPAS MC code with the adjusted transport parameters, can accurately transport electron and proton particles in magnetic field. This makes TOPAS a valuable tool for the determination ofkB. The ionization chambers we tested showed thatkBremains small (≤0.72%). To the best of our knowledge, this is the first calculations ofkBfor proton beams. This work represents a significant step forward in the development of MRgPT and protocols for proton dosimetry in presence of magnetic field.
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Affiliation(s)
- M Marot
- German Cancer Research Center (DKFZ), Medical Physics in Radiation Oncology, Heidelberg, Germany
- University of Heidelberg, Faculty of Medicine, Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - F Jäger
- German Cancer Research Center (DKFZ), Medical Physics in Radiation Oncology, Heidelberg, Germany
- University of Heidelberg, Faculty of Physics and Astronomy, Heidelberg, Germany
| | - S Greilich
- Berthold Technologies GmbH & Co. KG, Business Units Radiation Protection/Bioanalytics, Bad Wildbad, Germany
| | - C P Karger
- German Cancer Research Center (DKFZ), Medical Physics in Radiation Oncology, Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - O Jäkel
- German Cancer Research Center (DKFZ), Medical Physics in Radiation Oncology, Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), University Hospital Heidelberg, Heidelberg, Germany
| | - L N Burigo
- German Cancer Research Center (DKFZ), Medical Physics in Radiation Oncology, Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
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Simulation and Optimization of Optical Fiber Irradiation with X-rays at Different Energies. RADIATION 2023. [DOI: 10.3390/radiation3010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023] Open
Abstract
We investigated the influence of modifying the voltage of an X-ray tube with a tungsten anode between 30 kV and 225 kV, and therefore its photon energy spectrum (up to 225 keV), on the Total Ionizing Dose deposited in a single-mode, phosphorus-doped optical fiber, already identified as a promising dosimeter. Simulation data, obtained using a toolchain combining SpekPy and Geant4 software, are compared to experimental results obtained on this radiosensitive optical fiber and demonstrate an increase of the deposited dose with operating voltage, at a factor of 4.5 between 30 kV and 225 kV, while keeping the same operating current of 20 mA. Analysis of simulation results shows that dose deposition in such optical fibers is mainly caused by the low-energy part of the spectrum, with 90% of the deposited energy originating from photons with an energy below 30 keV. Comparison between simulation and various experimental measurements indicates that phosphosilicate fibers are adapted for performing X-ray dosimetry at different voltages.
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Iseri T, Tanabe Y, Onizuka R, Torigoe Y, Horikirizono H, Itamoto K, Sunahara H, Itoh H, Tani K, Nakaichi M. A Monte Carlo study on dose distribution of an orthovoltage radiation therapy system. Phys Eng Sci Med 2023; 46:623-632. [PMID: 36940063 DOI: 10.1007/s13246-023-01237-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/23/2023] [Indexed: 03/21/2023]
Abstract
It is important to plan radiotherapy treatment and establish optimal dose distribution to reduce the chances of side effects and injury. Because there are no commercially available tools for calculating dose distribution in orthovoltage radiotherapy in companion animals, we developed an algorithm to accomplish this and verified its characteristics using tumor disease cases. First, we used the Monte Carlo method to develop an algorithm to calculate the dose distribution of orthovoltage radiotherapy (280 kVp; MBR-320, Hitachi Medical Corporation, Tokyo, Japan) using BEAMnrc at our clinic. Using development of Monte Carlo method, dose distribution for tumor and normal organs were evaluated in brain tumors, squamous cell carcinomas of the head, and feline nasal lymphomas. In all cases of brain tumors, the mean dose delivered to the GTV ranged from 36.2 to 76.1% of the prescribed dose due to the decrease through the skull. In the nasal lymphoma in cats, the eyes with covered a 2 mm-thick lead plate, the respective average dose to the eyes was 71.8% and 89.9% less than that to the uncovered eyes. The findings may be useful for informed decision making in orthovoltage radiotherapy with more effective and targeted irradiation and data collection allowing detailed informed consent.
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Affiliation(s)
- Toshie Iseri
- Department of Veterinary Radiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi, Yamagishi, Japan.
| | - Yoshinori Tanabe
- Graduate School of Health Sciences, Okayama University, Okayama, Japan
| | - Ryouta Onizuka
- Department of Therapeutic Radiology, Yamaguchi University Hospital, Yamaguchi, Japan
| | - Yuri Torigoe
- Department of Veterinary Radiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi, Yamagishi, Japan
| | - Hiro Horikirizono
- Department of Veterinary Radiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi, Yamagishi, Japan
| | - Kazuhito Itamoto
- Animal medical center, Joint faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Hiroshi Sunahara
- Department of Veterinary Surgery, Joint faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Harumichi Itoh
- Animal medical center, Joint faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Kenji Tani
- Department of Veterinary Surgery, Joint faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Munekazu Nakaichi
- Department of Veterinary Radiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi, Yamagishi, Japan
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Chakraborty K, Mondal J, An JM, Park J, Lee YK. Advances in Radionuclides and Radiolabelled Peptides for Cancer Therapeutics. Pharmaceutics 2023; 15:pharmaceutics15030971. [PMID: 36986832 PMCID: PMC10054444 DOI: 10.3390/pharmaceutics15030971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Radiopharmaceutical therapy, which can detect and treat tumours simultaneously, was introduced more than 80 years ago, and it has changed medical strategies with respect to cancer. Many radioactive radionuclides have been developed, and functional, molecularly modified radiolabelled peptides have been used to produce biomolecules and therapeutics that are vastly utilised in the field of radio medicine. Since the 1990s, they have smoothly transitioned into clinical application, and as of today, a wide variety of radiolabelled radionuclide derivatives have been examined and evaluated in various studies. Advanced technologies, such as conjugation of functional peptides or incorporation of radionuclides into chelating ligands, have been developed for advanced radiopharmaceutical cancer therapy. New radiolabelled conjugates for targeted radiotherapy have been designed to deliver radiation directly to cancer cells with improved specificity and minimal damage to the surrounding normal tissue. The development of new theragnostic radionuclides, which can be used for both imaging and therapy purposes, allows for more precise targeting and monitoring of the treatment response. The increased use of peptide receptor radionuclide therapy (PRRT) is also important in the targeting of specific receptors which are overexpressed in cancer cells. In this review, we provide insights into the development of radionuclides and functional radiolabelled peptides, give a brief background, and describe their transition into clinical application.
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Affiliation(s)
- Kushal Chakraborty
- Department of IT and Energy Convergence (BK21 FOUR), Korea National University of Transportation, Chungju 27469, Republic of Korea
| | - Jagannath Mondal
- Department of Green Bio Engineering, Graduate School, Korea National University of Transportation, Chungju 27469, Republic of Korea
- 4D Convergence Technology Institute, Korea National University of Transportation, Jeungpyeong 27909, Republic of Korea
| | - Jeong Man An
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Jooho Park
- Department of Applied Life Science, Graduate School, BK21 Program, Konkuk University, Chungju 27478, Republic of Korea
- Research Institute for Biomedical & Health Science, Konkuk University, Chungju 27478, Republic of Korea
- Correspondence: (J.P.); (Y.-K.L.); Tel.: +82-43-841-5224 (Y.-K.L.)
| | - Yong-Kyu Lee
- Department of Green Bio Engineering, Graduate School, Korea National University of Transportation, Chungju 27469, Republic of Korea
- 4D Convergence Technology Institute, Korea National University of Transportation, Jeungpyeong 27909, Republic of Korea
- Correspondence: (J.P.); (Y.-K.L.); Tel.: +82-43-841-5224 (Y.-K.L.)
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Monte-Carlo techniques for radiotherapy applications II: equipment and source modelling, dose calculations and radiobiology. JOURNAL OF RADIOTHERAPY IN PRACTICE 2023. [DOI: 10.1017/s1460396923000080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Abstract
Introduction:
This is the second of two papers giving an overview of the use of Monte-Carlo techniques for radiotherapy applications.
Methods:
The first paper gave an introduction and introduced some of the codes that are available to the user wishing to model the different aspects of radiotherapy treatment. It also aims to serve as a useful companion to a curated collection of papers on Monte-Carlo that have been published in this journal.
Results and Conclusions:
This paper focuses on the application of Monte-Carlo to specific problems in radiotherapy. These include radiotherapy and imaging beam production, brachytherapy, phantom and patient dosimetry, detector modelling and track structure calculations for micro-dosimetry, nano-dosimetry and radiobiology.
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Jean E, Lambert-Girard S, Therriault-Proulx F, Beaulieu L. Hybrid Cerenkov-scintillation detector validation using Monte Carlo simulations. Phys Med Biol 2022; 68. [PMID: 36541552 DOI: 10.1088/1361-6560/aca74d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022]
Abstract
Objective.This study aimed at investigating through Monte Carlo simulations the limitations of a novel hybrid Cerenkov-scintillation detector and the associated method for irradiation angle measurements.Approach.Using Monte Carlo simulations, previous experimental irradiations of the hybrid detector with a linear accelerator were replicated to evaluate its general performances and limitations. Cerenkov angular calibration curves and irradiation angle measurements were then compared. Furthermore, the impact of the Cerenkov light energy dependency on the detector accuracy was investigated using the energy spectra of electrons travelling through the detector.Main results.Monte Carlo simulations were found to be in good agreement with experimental values. The irradiation angle absolute mean error was found to be less than what was obtained experimentally, with a maximum value of 1.12° for the 9 MeV beam. A 0.4% increase of the ratio of electrons having an energy below 1 MeV to the total electrons was found to impact the Cerenkov light intensity collected as a function of the incident angle. The effect of the Cerenkov intensity variation on the measured angle was determined to vary according to the slope of the angular calibration curve. While the contribution of scattered electrons with a lower energy affects the detector accuracy, the greatest discrepancies result from the limitations of the calculation method and the calibration curve itself.Significance.A precise knowledge of the limitations of the hybrid detector and the irradiation angle calculation method is crucial for a clinical implementation. Moreover, the simulations performed in this study also corroborate hypotheses made regarding the relations between multiple Cerenkov dependencies and observations from the experimental measurements.
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Affiliation(s)
- Emilie Jean
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, Quebec, QC, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec - Université Laval, Quebec, QC, Canada.,Département de radio-oncologie du CIUSSS-MCQ, CHAUR de Trois-Rivières, Trois-Rivières, QC, Canada
| | | | | | - Luc Beaulieu
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, Quebec, QC, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec - Université Laval, Quebec, QC, Canada
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Abdul Hadi MFR, Abdullah AN, Hashikin NAA, Ying CK, Yeong CH, Yoon TL, Ng KH, Ng KH. Utilizing 3D Slicer to incorporate tomographic images into GATE Monte Carlo simulation for personalized dosimetry in yttrium-90 radioembolization. Med Phys 2022; 49:7742-7753. [PMID: 36098271 DOI: 10.1002/mp.15980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Monte Carlo (MC) simulation is an important technique that can help design advanced and challenging experimental setups. GATE (Geant4 application for tomographic emission) is a useful simulation toolkit for applications in nuclear medicine. Transarterial radioembolization is a treatment for liver cancer, where microspheres embedded with yttrium-90 (90 Y) are administered intra-arterially to the tumor. Personalized dosimetry for this treatment may provide higher dosimetry accuracy compared to the conventional partition model (PM) calculation. However, incorporation of three-dimensional tomographic input data into MC simulation is an intricate process. In this article, 3D Slicer, free and open-source software, was utilized for the incorporation of patient tomographic images into GATE to demonstrate the feasibility of personalized dosimetry in hepatic radioembolization with 90 Y. METHODS In this article, the steps involved in importing, segmenting, and registering tomographic images using 3D Slicer were thoroughly described, before importing them into GATE for MC simulation. The absorbed doses estimated using GATE were then compared with that of PM. SlicerRT, a 3D Slicer extension, was then used to visualize the isodose from the MC simulation. RESULTS A workflow diagram consisting of all the steps taken in the utilization of 3D Slicer for personalized dosimetry in 90 Y radioembolization has been presented in this article. In comparison to the MC simulation, the absorbed doses to the tumor and normal liver were overestimated by PM by 105.55% and 20.23%, respectively, whereas for lungs, the absorbed dose estimated by PM was underestimated by 25.32%. These values were supported by the isodose distribution obtained via SlicerRT, suggesting the presence of beta particles outside the volumes of interest. These findings demonstrate the importance of personalized dosimetry for a more accurate absorbed dose estimation compared to PM. CONCLUSION The methodology provided in this study can assist users (especially students or researchers who are new to MC simulation) in navigating intricate steps required in the importation of tomographic data for MC simulation. These steps can also be utilized for other radiation therapy related applications, not necessarily limited to internal dosimetry.
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Affiliation(s)
| | | | | | - Chee Keat Ying
- Oncological & Radiological Science Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Pulau Pinang, 13200, Malaysia
| | - Chai Hong Yeong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya, Selangor, 47500, Malaysia
| | - Tiem Leong Yoon
- School of Physics, Universiti Sains Malaysia, USM, Penang, 11800, Malaysia
| | - Kwan Hoong Ng
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Federal Territory of Kuala Lumpur, 50603, Malaysia.,Faculty of Medicine and Health Sciences, UCSI University, Port Dickson, Negeri Sembilan, 71010, Malaysia
| | - Kwan Hoong Ng
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603, Malaysia.,Faculty of Medicine and Health Sciences, UCSI University. 71010 Port Dickson, Negeri Sembilan, Malaysia
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Kara A. An optimization study for targeted alpha therapy: Ion behaviours and dose calculations within ICRU-compact bone tissue. Appl Radiat Isot 2022; 191:110552. [DOI: 10.1016/j.apradiso.2022.110552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/27/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022]
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Shende R, Dhoble S, Gupta G. Geometrical source modeling of 6MV flattening-filter-free (FFF) beam from TrueBeam linear accelerator and its commissioning validation using Monte Carlo simulation approach for radiotherapy. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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12
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Calvo-Ortega JF, Moragues-Femenía S, Laosa-Bello C, Hermida-López M, Pozo-Massó M, Zamora-Pérez A. Monte Carlo-based independent dose verification of radiosurgery HyperArc plans. Phys Med 2022; 102:19-26. [PMID: 36037748 DOI: 10.1016/j.ejmp.2022.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 08/07/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate the feasibility of using the free PRIMO Monte Carlo software for independent dose check of cranial SRS plans designed with the Varian HyperArc (HA) technique. MATERIALS AND METHODS In this study, the PRIMO Monte Carlo software v. 0.3.64.1800 was used with the phase-space files (v. 2, Feb. 27, 2013) provided by Varian for 6 MV flattening-filter-free (FFF) photon beams from a Varian TrueBeam linear accelerator (linac), equipped with a Millennium 120 multileaf collimator (MLC). This configuration was validated by comparing the percentage depth doses (PDDs), lateral profiles and relative output factors (OFs) simulated in a water phantom against measurements for field sizes from 1 × 1 to 40 × 40 cm2. The agreement between simulated and experimental relative dose curves was evaluated using a global (G) gamma index analysis. In addition, the accuracy of PRIMO to model the MLC was investigated (dosimetric leaf gap, tongue and groove, leaf transmission and interleaf leakage). Thirty-five HA SRS plans computed in the Eclipse treatment planning system (TPS) were simulated in PRIMO. The Acuros XB algorithm v. 16.10 (dose to medium) was used in Eclipse. Sixty targets with diameters ranging from 6 to 33 mm were included. Agreement between the dose distributions given by Eclipse and PRIMO was evaluated in terms of 3D global gamma passing rates (GPRs) for the 2 %/2 mm criteria. RESULTS Average GPR greater than 95 % with the 2 %(G)/1 mm criteria were obtained over the PDD and profiles of each field size. Differences between PRIMO calculated and measured OFs were within 0.5 % in all fields, except for the 1 × 1 cm2 with a discrepancy of 1.5 %. Regarding the MLC modeling in PRIMO, an agreement within 3 % was achieved between calculated and experimental doses. Excellent agreement between PRIMO and Eclipse was found for the 35 HA plans. The 3D global GPRs (2 %/2 mm) for the targets and external patient contour were 99.6 % ± 1.1 % and 99.8 % ± 0.5 %, respectively. CONCLUSIONS According to the results described in this study, the PRIMO Monte Carlo software, in conjunction with the 6X FFF Varian phase-space files, can be used as secondary dose calculation software to check stereotactic radiosurgery plans from Eclipse using the HyperArc technique.
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Affiliation(s)
- Juan-Francisco Calvo-Ortega
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain; Servicio de Oncología Radioterápica, Hospital Quirónsalud, Málaga, Spain.
| | | | - Coral Laosa-Bello
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain
| | - Marcelino Hermida-López
- Marcelino Hermida-López. Servei de Física i Protecció Radiològica, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Miguel Pozo-Massó
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain
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13
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Investigation of the effects of the step size of Geant4 electromagnetic physics on the depth dose simulation of a small field proton beam. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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14
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Failing T, Hartmann GH, Hensley FW, Keil B, Zink K. Enhancement of the EGSnrc code egs_chamber for fast fluence calculations of charged particles. Z Med Phys 2022; 32:417-427. [PMID: 35643800 PMCID: PMC9948836 DOI: 10.1016/j.zemedi.2022.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/29/2022] [Accepted: 04/14/2022] [Indexed: 11/19/2022]
Abstract
PURPOSE Simulation of absorbed dose deposition in a detector is one of the key tasks of Monte Carlo (MC) dosimetry methodology. Recent publications (Hartmann and Zink, 2018; Hartmann and Zink, 2019; Hartmann et al., 2021) have shown that knowledge of the charged particle fluence differential in energy contributing to absorbed dose is useful to provide enhanced insight on how response depends on detector properties. While some EGSnrc MC codes provide output of charged particle spectra, they are often restricted in setup options or limited in calculation efficiency. For detector simulations, a promising approach is to upgrade the EGSnrc code egs_chamber which so far does not offer charged particle calculations. METHODS Since the user code cavity offers charged particle fluence calculation, the underlying algorithm was embedded in egs_chamber. The modified code was tested against two EGSnrc applications and DOSXYZnrc which was modified accordingly by one of the authors. Furthermore, the gain in efficiency achieved by photon cross section enhancement was determined quantitatively. RESULTS Electron and positron fluence spectra and restricted cema calculated by egs_chamber agreed well with the compared applications thus demonstrating the feasibility of the new code. Additionally, variance reduction techniques are now applicable also for fluence calculations. Depending on the simulation setup, considerable gains in efficiency were obtained by photon cross section enhancement. CONCLUSION The enhanced egs_chamber code represents a valuable tool to investigate the response of detectors with respect to absorbed dose and fluence distribution and the perturbation caused by the detector in a reasonable computation time. By using intermediate phase space scoring, egs_chamber offers parallel calculation of charged particle fluence spectra for different detector configurations in one single run.
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Affiliation(s)
- Thomas Failing
- Department for Radiotherapy and Radiooncology, University Medical Center Göttingen, Göttingen 37075, Germany; Institute of Medical Physics and Radiation Protection (IMPS), University of Applied Sciences, Gießen 35390, Germany.
| | | | - Frank W Hensley
- Department for Radiotherapy and Radiooncology, University Medical Center Heidelberg, Heidelberg 69120, Germany
| | - Boris Keil
- Institute of Medical Physics and Radiation Protection (IMPS), University of Applied Sciences, Gießen 35390, Germany; Diagnostic and Interventional Radiology, Philipps-University Marburg, Marburg 35043, Germany
| | - Klemens Zink
- Institute of Medical Physics and Radiation Protection (IMPS), University of Applied Sciences, Gießen 35390, Germany; Department for Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg 35043, Germany; Marburg Iontherapy Center (MIT), Marburg 35043, Germany
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15
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Kaveckyte V, Jørgensen EB, Kertzscher G, Johansen JG, Tedgren ÅC. Monte Carlo characterization of high atomic number inorganic scintillators for in vivo dosimetry in 192 Ir brachytherapy. Med Phys 2022; 49:4715-4730. [PMID: 35443079 DOI: 10.1002/mp.15674] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/01/2022] [Accepted: 04/06/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND There is increased interest in vivo dosimetry for 192 Ir brachytherapy (BT) treatments using high atomic number (Z) inorganic scintillators. Their high light output enables construction of small detectors with negligible stem effect and simple readout electronics. Experimental determination of absorbed-dose energy dependence of detectors relative to water is prevalent, but it can be prone to high detector positioning uncertainties and does not allow for decoupling of absorbed-dose energy dependence from other factors affecting detector response. PURPOSE To investigate which measurement conditions and detector properties could affect their absorbed-dose energy dependence in BT in vivo dosimetry. METHODS We used a general-purpose MC code penelope for the characterization of high-Z inorganic scintillators with the focus on ZnSe (Z¯=32). Two other promising media CsI (Z¯=54) and Al2 O3 (Z¯=11) were included for comparison in selected scenarios. We determined absorbed-dose energy dependence of crystals relative to water under different scatter conditions (calibration phantom 12 × 12 × 30 cm3 , characterization phantoms 20 × 20 × 20 cm3 , 30 × 30 × 30 cm3 , 40 × 40 × 40 cm3 , and patient-like elliptic phantom 40 × 30 × 25 cm3 ). To mimic irradiation conditions during prostate treatments, we evaluated whether the presence of pelvic bones and calcifications affect ZnSe response. ZnSe detector design influence was also investigated. RESULTS In contrast to low-Z organic and medium-Z inorganic scintillators, ZnSe and CsI media have substantially greater absorbed-dose energy dependence relative to water. The response was phantom-size dependent and changed by 11 % between limited- and full-scatter conditions for ZnSe, but not for Al2 O3 . For a given phantom size, a part of the absorbed-dose energy dependence of ZnSe is caused not due to in-phantom scatter but due to source anisotropy. Thus, the absorbed-dose energy dependence of high-Z scintillators is a function of not only the radial distance but also the polar angle. Pelvic bones did not affect ZnSe response, whereas large and intermediate size calcifications reduced it by 9 % and 5 %, respectively, when placed midway between the source and the detector. CONCLUSIONS Unlike currently prevalent low- and medium-Z scintillators, high-Z crystals are sensitive to characterization and in vivo measurement conditions. However, good agreement between MC data for ZnSe in the present study and experimental data for ZnSe:O by Jørgensen et al (2021) suggest that detector signal is proportional to the average absorbed dose to the detector cavity. This enables an easy correction for non-TG43-like scenarios (e.g., patient sizes and calcifications) through MC simulations. Information that should be provided to the clinic by the detector vendors. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Vaiva Kaveckyte
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, SE-581 85, Sweden
| | - Erik B Jørgensen
- Department of Clinical Medicine, Aarhus University, Aarhus, DK-8000, Denmark.,Department of Oncology, Aarhus University Hospital, Aarhus, DK-8000, Denmark
| | - Gustavo Kertzscher
- Department of Oncology, Aarhus University Hospital, Aarhus, DK-8000, Denmark
| | - Jacob G Johansen
- Department of Clinical Medicine, Aarhus University, Aarhus, DK-8000, Denmark.,Department of Oncology, Aarhus University Hospital, Aarhus, DK-8000, Denmark
| | - Åsa Carlsson Tedgren
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, SE-581 85, Sweden.,Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, SE-171 76, Sweden.,Department of Oncology-Pathology, Karolinska Institute, Stockholm, SE-171 76, Sweden
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16
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Use of calculations to validate beam quality and relative dose measurements for a kilovoltage X-ray therapy unit. Phys Eng Sci Med 2022; 45:537-546. [PMID: 35381970 DOI: 10.1007/s13246-022-01120-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
Abstract
Relative dosimetry measurements are required to fully commission kilovoltage X-ray units for superficial and orthovoltage X-ray therapy. Validation of these relative dosimetry measurements with Monte Carlo methods is advantageous being independent of the measurement process. In this study use is made of the X-ray spectrum generating program SpekPy along with the EGSnrc Monte Carlo code to calculate depth doses and explore the dosimetry effect of changes in backscatter. These calculations are compared with previously reported measurements for the Pantak SXT 150 X-ray therapy unit. SpekPy can also be used to generate half value layer (HVL) values and these are also compared to previously reported HVL measurements for the same X-ray therapy unit. It was found that agreements of the order of 5% in HVL, 3% in depth dose and 1% in backscatter doses were found between Monte Carlo calculations and the previously published measured data. Exit doses in conditions of lack of full backscatter were explored with Monte Carlo calculations demonstrating reduced exit dose up to 20% in these conditions. It is concluded that SpekPy with Monte Carlo codes such as EGSnrc provides a straightforward approach to validating various relative dosimetry measurements in kilovoltage X-ray dosimetry.
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17
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Olaciregui-Ruiz I, Osinga-Blaettermann JM, Ortega-Marin K, Mijnheer B, Mans A. Extending in aqua portal dosimetry with dose inhomogeneity conversion maps for accurate patient dose reconstruction in external beam radiotherapy. Phys Imaging Radiat Oncol 2022; 22:20-27. [PMID: 35493851 PMCID: PMC9038561 DOI: 10.1016/j.phro.2022.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 11/24/2022] Open
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18
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Dosimetry procedure to verify dose in High Dose Rate (HDR) brachytherapy treatment of cancer patients: A systematic review. Phys Med 2022; 96:70-80. [DOI: 10.1016/j.ejmp.2022.02.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 01/12/2023] Open
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19
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Duchaine J, Wahl M, Markel D, Bouchard H. A probabilistic approach for determining Monte Carlo beam source parameters: II. Impact of beam modeling uncertainties on dosimetric functions and treatment plans. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4efb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/26/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. The Monte Carlo method is recognized as a valid approach for the evaluation of dosimetric functions for clinical use. This procedure requires the accurate modeling of the considered linear accelerator. In Part I, we propose a new method to extract the probability density function of the beam model physical parameters. The aim of this work is to evaluate the impact of beam modeling uncertainties on Monte Carlo evaluated dosimetric functions and treatment plans in the context of small fields. Approach. Simulations of output factors, output correction factors, dose profiles, percent-depth doses and treatment plans are performed using the CyberKnife M6 model developed in Part I. The optimized pair of electron beam energy and spot size, and eight additional pairs of beam parameters representing a 95% confidence region are used to propagate the uncertainties associated to the source parameters to the dosimetric functions. Main results. For output factors, the impact of beam modeling uncertainties increases with the reduction of the field size and confidence interval half widths reach 1.8% for the 5 mm collimator. The impact on output correction factors cancels in part, leading to a maximum confidence interval half width of 0.44%. The impact is less significant for percent-depth doses in comparison to dose profiles. For these types of measurement, in absolute terms and in comparison to the reference dose, confidence interval half widths less than or equal to 1.4% are observed. For simulated treatment plans, the impact is more significant for the treatment delivered with a smaller field size with confidence interval half widths reaching 2.5% and 1.4% for the 5 and 20 mm collimators, respectively. Significance. Results confirm that AAPM TG-157's tolerances cannot apply to the field sizes studied. This study provides an insight on the reachable dose calculation accuracy in a clinical setup.
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20
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Duchaine J, Markel D, Bouchard H. A probabilistic approach for determining Monte Carlo beam source parameters: I. Modeling of a CyberKnife M6 unit. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4ef7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 01/26/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. During Monte Carlo modeling of external radiotherapy beams, models must be adjusted to reproduce the experimental measurements of the linear accelerator being considered. The aim of this work is to propose a new method for the determination of the energy and spot size of the electron beam incident on the target of a linear accelerator using a maximum likelihood estimation. Approach. For that purpose, the method introduced by Francescon et al (2008 Med. Phys.
35 504–13) is expanded upon in this work. Simulated tissue-phantom ratios and uncorrected output factors using a set of different detector models are compared to experimental measurements. A probabilistic formalism is developed and a complete uncertainty budget, which includes a detailed simulation of positioning errors, is evaluated. The method is applied to a CyberKnife M6 unit using four detectors (PTW 60012, PTW 60019, Exradin A1SL and IBA CC04), with simulations being performed using the EGSnrc suite. Main results. The likelihood distributions of the electron beam energy and spot size are evaluated, leading to
E
ˆ
=
7.42
±
0.17
MeV
and
F
ˆ
=
2.15
±
0.06
mm
. Using these results and a 95% confidence region, simulations reproduce measurements in 13 out of the 14 considered setups. Significance. The proposed method allows an accurate beam parameter optimization and uncertainty evaluation during the Monte Carlo modeling of a radiotherapy unit.
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21
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Lee BI, Boss MK, LaRue SM, Martin T, Leary D. Comparative study of the collapsed cone convolution and Monte Carlo algorithms for radiation therapy planning of canine sinonasal tumors reveals significant dosimetric differences. Vet Radiol Ultrasound 2021; 63:91-101. [PMID: 34755417 DOI: 10.1111/vru.13039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 11/30/2022] Open
Abstract
Computer-based radiation therapy requires high targeting and dosimetric precision. Analytical dosimetric algorithms typically are fast and clinically viable but can have increasing errors near air-bone interfaces. These are commonly found within dogs undergoing radiation planning for sinonasal cancer. This retrospective methods comparison study is designed to compare the dosimetry of both tumor volumes and organs at risk and quantify the differences between collapsed cone convolution (CCC) and Monte Carlo (MC) algorithms. Canine sinonasal tumor plans were optimized with CCC and then recalculated by MC with identical control points and monitor units. Planning target volume (PTV)air , PTVsoft tissue , and PTVbone were created to analyze the dose discrepancy within the PTV. Thirty imaging sets of dogs were included. Monte Carlo served as the gold standard calculation for the dosimetric comparison. Collapsed cone convolution overestimated the mean dose (Dmean ) to PTV and PTVsoft tissue by 0.9% and 0.5%, respectively (both P < 0.001). Collapsed cone convolution overestimated Dmean to PTVbone by 3% (P < 0.001). Collapsed cone convolution underestimated the near-maximum dose (D2 ) to PTVair by 1.1% (P < 0.001), and underestimated conformity index and homogeneity index in PTV (both P < 0.001). Mean doses of contralateral and ipsilateral eyes were overestimated by CCC by 1.6% and 1.7%, respectively (both P < 0.001). Near-maximum doses of skin and brain were overestimated by CCC by 2.2% and 0.7%, respectively (both P < 0.001). As clinical accessibility of Monte Carlo becomes more widespread, dose constraints may need to be re-evaluated with appropriate plan evaluation and follow-up.
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Affiliation(s)
- Ber-In Lee
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Mary-Keara Boss
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Susan M LaRue
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Tiffany Martin
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Del Leary
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
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22
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Hartmann GH, Andreo P, Kapsch RP, Zink K. Cema-based formalism for the determination of absorbed dose for high-energy photon beams. Med Phys 2021; 48:7461-7475. [PMID: 34613620 DOI: 10.1002/mp.15266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 07/26/2021] [Accepted: 09/23/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Determination of absorbed dose is well established in many dosimetry protocols and considered to be highly reliable using ionization chambers under reference conditions. If dosimetry is performed under other conditions or using other detectors, however, open questions still remain. Such questions frequently refer to appropriate correction factors. A converted energy per mass (cema)-based approach to formulate such correction factors offers a good understanding of the specific response of a detector for dosimetry under various measuring conditions and thus an estimate of pros and cons of its application. METHODS Determination of absorbed dose requires the knowledge of the beam quality correction factor kQ,Qo , where Q denotes the quality of a user beam and Qo is the quality of the radiation used for calibration. In modern Monte Carlo (MC)-based methods, kQ,Qo is directly derived from the MC-calculated dose conversion factor, which is the ratio between the absorbed dose at a point of interest in water and the mean absorbed dose in the sensitive volume of an ion chamber. In this work, absorbed dose is approximated by the fundamental quantity cema. This approximation allows the dose conversion factor to be substituted by the cema conversion factor. Subsequently, this factor is decomposed into a product of cema ratios. They are identified as the stopping power ratio water to the material in the sensitive detector volume, and as the correction factor for the fluence perturbation of the secondary charged particles in the detector cavity caused by the presence of the detector. This correction factor is further decomposed with respect to the perturbation caused by the detector cavity and that caused by external detector properties. The cema-based formalism was subsequently tested by MC calculations of the spectral fluence of the secondary charged particles (electrons and positrons) under various conditions. RESULTS MC calculations demonstrate that considerable fluence perturbation may occur particularly under non-reference conditions. Cema-based correction factors to be applied in a 6-MV beam were obtained for a number of ionization chambers and for three solid-state detectors. Feasibility was shown at field sizes of 4 × 4 and 0.5 cm × 0.5 cm. Values of the cema ratios resulting from the decomposition of the dose conversion factor can be well correlated with detector response. Under the small field conditions, the internal fluence correction factor of ionization chambers is considerably dependent on volume averaging and thus on the shape and size of the cavity volume. CONCLUSIONS The cema approach is particularly useful at non-reference conditions including when solid-state detectors are used. Perturbation correction factors can be expressed and evaluated by cema ratios in a comprehensive manner. The cema approach can serve to understand the specific response of a detector for dosimetry to be dependent on (a) radiation quality, (b) detector properties, and (c) electron fluence changes caused by the detector. This understanding may also help to decide which detector is best suited for a specific measurement situation.
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Affiliation(s)
- Günther H Hartmann
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Pedro Andreo
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden.,Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | | | - Klemens Zink
- Institut fuer Medizinische Physik und Strahlenschutz (IMPS), University of Applied Sciences, Giessen, Giessen, Germany.,Department for Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany.,Marburg Iontherapy Center (MIT), Marburg, Germany
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23
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Liu B, Xiong T, Lu J, Li S, Bai X, Zhou F, Wu Q. Technical note: A fast and accurate analytical dose calculation algorithm for 125 I seed-loaded stent applications. Med Phys 2021; 48:7493-7503. [PMID: 34482556 DOI: 10.1002/mp.15207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 08/12/2021] [Accepted: 08/28/2021] [Indexed: 12/09/2022] Open
Abstract
PURPOSE The safety and clinical efficacy of 125 I seed-loaded stent for the treatment of portal vein tumor thrombosis (PVTT) have been shown. Accurate and fast dose calculation of the 125 I seeds with the presence of the stent is necessary for the plan optimization and evaluation. However, the dosimetric characteristics of the seed-loaded stents remain unclear and there is no fast dose calculation technique available. This paper aims to explore a fast and accurate analytical dose calculation method based on Monte Carlo (MC) dose calculation, which takes into account the effect of stent and tissue inhomogeneity. METHODS A detailed model of the seed-loaded stent was developed using 3D modeling software and subsequently used in MC simulations to calculate the dose distribution around the stent. The dose perturbation caused by the presence of the stent was analyzed, and dose perturbation kernels (DPKs) were derived and stored for future use. Then, the dose calculation method from AAPM TG-43 was adapted by integrating the DPK and appropriate inhomogeneity correction factors (ICF) to calculate dose distributions analytically. To validate the proposed method, several comparisons were performed with other methods in water phantom and voxelized CT phantoms for three patients. RESULTS The stent has a considerable dosimetric effect reducing the dose up to 47.2% for single-seed stent and 11.9%-16.1% for 16-seed stent. In a water phantom, dose distributions from MC simulations and TG-43-DP-ICF showed a good agreement with the relative error less than 3.3%. In voxelized CT phantoms, taking MC results as the reference, the relative errors of TG-43 method can be up to 33%, while those of TG-43-DP-ICF method were less than 5%. For a dose matrix with 256 × 256 × 46 grid (corresponding to a phantom of 17.2 × 17.2 × 11.5 cm3 ) for 16-seed-loaded stent, it only takes 17 s for TG-43-DP-ICF to compute, compared to 25 h for the full MC calculation. CONCLUSIONS The combination of DPK and inhomogeneity corrections is an effective approach to handle both the presence of stent and tissue heterogeneity. Exhibiting good agreement with MC calculation and computational efficiency, the proposed TG-43-DP-ICF method is adequate for dose evaluation and optimization in seed-loaded stent implantation treatment planning.
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Affiliation(s)
- Bo Liu
- Image Processing Center, Beihang University, Beijing, People's Republic of China.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, People's Republic of China
| | - Tianyu Xiong
- Department of Physics, Beihang University, Beijing, People's Republic of China
| | - Jian Lu
- Center of Interventional Radiology & Vascular Surgery, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
| | - Shengwei Li
- Center of Interventional Radiology & Vascular Surgery, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
| | - Xiangzhi Bai
- Image Processing Center, Beihang University, Beijing, People's Republic of China.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, People's Republic of China
| | - Fugen Zhou
- Image Processing Center, Beihang University, Beijing, People's Republic of China.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, People's Republic of China
| | - Qiuwen Wu
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
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24
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Kaveckyte V, Carlsson Tedgren Å, Fernández-Varea JM. Impact of the I-value of diamond on the energy deposition in different beam qualities. Phys Med Biol 2021; 66. [PMID: 34014176 DOI: 10.1088/1361-6560/ac028f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/18/2021] [Indexed: 11/12/2022]
Abstract
Diamond detectors are increasingly employed in dosimetry. Their response has been investigated by means of Monte Carlo (MC) methods, but there is no consensus on what mass densityρ, mean excitation energyIand number of conduction electrons per atomnceto use in the simulations. The ambiguity occurs due to its seeming similarity with graphite (both are carbon allotropes). Except for the difference inρbetween crystalline graphite (2.265 g cm-3) and diamond (3.515 g cm-3), their dielectric properties are assumed to be identical. This is incorrect, and the two materials should be distinguished: (ρ= 2.265 g cm-3,I= 81.0 eV,nce= 1) for graphite and (ρ= 3.515 g cm-3,I= 88.5 eV,nce= 0) for diamond. Simulations done with the MC codepenelopeshow that the energy imparted in diamond decreases by up to 1% with respect to 'pseudo-diamond' (ρ= 3.515 g cm-3,I= 81.0 eV,nce= 0) depending on the beam quality and cavity thickness. The energy imparted changed the most in cavities that are small compared with the range of electrons. The difference in the density-effect term relative to graphite was the smallest for diamond owing to an interplay effect thatρ,Iandncehave on this term, in contrast to pseudo-diamond media when eitherρorIalone were adjusted. The study also presents a parameterized density-effect correction function for diamond that may be used by MC codes like EGSnrc. Theestarprogram assumes thatnce= 2 for all carbon-based materials, hence it delivers an erroneous density-effect correction term for graphite and diamond. Despite the small changes of the energy imparted in diamond simulated with two differentIvalues and expected close-to-negligible deviation from the published small-field output correction data, it is important to pay attention to material properties and model the medium faithfully.
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Affiliation(s)
- Vaiva Kaveckyte
- Department of Health, Medicine and Caring Sciences, Linköping University, SE-58185 Linköping, Sweden.,Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, SE-17176 Stockholm, Sweden
| | - Åsa Carlsson Tedgren
- Department of Health, Medicine and Caring Sciences, Linköping University, SE-58185 Linköping, Sweden.,Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, SE-17176 Stockholm, Sweden
| | - José M Fernández-Varea
- Facultat de Física (FQA and ICC), Universitat de Barcelona, Diagonal 645, E-08028 Barcelona, Catalonia, Spain
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25
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Calvo‐Ortega J, Greer PB, Hermida‐López M, Moragues‐Femenía S, Laosa‐Bello C, Casals‐Farran J. Validation of virtual water phantom software for pre-treatment verification of single-isocenter multiple-target stereotactic radiosurgery. J Appl Clin Med Phys 2021; 22:241-252. [PMID: 34028955 PMCID: PMC8200437 DOI: 10.1002/acm2.13269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 02/05/2021] [Accepted: 04/13/2021] [Indexed: 11/09/2022] Open
Abstract
The aim of this study was to benchmark the accuracy of the VIrtual Phantom Epid dose Reconstruction (VIPER) software for pre-treatment dosimetric verification of multiple-target stereotactic radiosurgery (SRS). VIPER is an EPID-based method to reconstruct a 3D dose distribution in a virtual phantom from in-air portal images. Validation of the VIPER dose calculation was assessed using several MLC-defined fields for a 6 MV photon beam. Central axis percent depth doses (PDDs) and output factors were measured with an ionization chamber in a water tank, while dose planes at a depth of 10 cm in a solid flat phantom were acquired with radiochromic films. The accuracy of VIPER for multiple-target SRS plan verification was benchmarked against Monte Carlo simulations. Eighteen multiple-target SRS plans designed with the Eclipse treatment planning system were mapped to a cylindrical water phantom. For each plan, the 3D dose distribution reconstructed by VIPER within the phantom was compared with the Monte Carlo simulation, using a 3D gamma analysis. Dose differences (VIPER vs. measurements) generally within 2% were found for the MLC-defined fields, while film dosimetry revealed gamma passing rates (GPRs) ≥95% for a 3%/1 mm criteria. For the 18 multiple-target SRS plans, average 3D GPRs greater than 93% and 98% for the 3%/2 mm and 5%/2 mm criteria, respectively. Our results validate the use of VIPER as a dosimetric verification tool for pre-treatment QA of single-isocenter multiple-target SRS plans. The method requires no setup time on the linac and results in an accurate 3D characterization of the delivered dose.
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Affiliation(s)
- Juan‐Francisco Calvo‐Ortega
- Servicio de Oncología RadioterápicaHospital QuirónsaludBarcelonaSpain
- Servicio de Oncología RadioterápicaHospital Universitari DexeusBarcelonaSpain
| | - Peter B. Greer
- Department of Radiation OncologyCalvary Mater Newcastle HospitalNewcastleNSW2298Australia
- School of Mathematical and Physical SciencesUniversity of NewcastleNewcastleNSW2300Australia
| | | | - Sandra Moragues‐Femenía
- Servicio de Oncología RadioterápicaHospital QuirónsaludBarcelonaSpain
- Servicio de Oncología RadioterápicaHospital Universitari DexeusBarcelonaSpain
| | - Coral Laosa‐Bello
- Servicio de Oncología RadioterápicaHospital QuirónsaludBarcelonaSpain
- Servicio de Oncología RadioterápicaHospital Universitari DexeusBarcelonaSpain
| | - Joan Casals‐Farran
- Servicio de Oncología RadioterápicaHospital QuirónsaludBarcelonaSpain
- Servicio de Oncología RadioterápicaHospital Universitari DexeusBarcelonaSpain
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Bolsa-Ferruz M, Palmans H, Boersma D, Stock M, Grevillot L. Monte Carlo computation of 3D distributions of stopping power ratios in light ion beam therapy using GATE-RTion. Med Phys 2021; 48:2580-2591. [PMID: 33465819 DOI: 10.1002/mp.14726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/11/2020] [Accepted: 12/20/2020] [Indexed: 12/18/2022] Open
Abstract
PURPOSE This paper presents a novel method for the calculation of three-dimensional (3D) Bragg-Gray water-to-detector stopping power ratio (sw,det ) distributions for proton and carbon ion beams. METHODS Contrary to previously published fluence-based calculations of the stopping power ratio, the sw,det calculation method used in this work is based on the specific way GATE/Geant4 scores the energy deposition. It only requires the use of the so-called DoseActor, as available in GATE, for the calculation of the sw,det at any point of a 3D dose distribution. The simulations are performed using GATE-RTion v1.0, a dedicated GATE release that was validated for the clinical use in light ion beam therapy. RESULTS The Bragg-Gray water-to-air stopping power ratio (sw,air ) was calculated for monoenergetic proton and carbon ion beams with the default stopping power data in GATE-RTion v1.0 and the new ICRU90 recommendation. The sw,air differences between the use of the default and the ICRU90 configuration were 0.6% and 5.4% at the physical range (R80 - 80% dose level in the distal dose fall-off) for a 70 MeV proton beam and a 120 MeV/u carbon ion beam, respectively. For protons, the sw,det results for lithium fluoride, silicon, gadolinium oxysulfide, and the active layer material of EBT2 (radiochromic film) were compared with the literature and a reasonable agreement was found. For a real patient treatment plan, the 3D distributions of sw,det in proton beams were calculated. CONCLUSIONS Our method was validated by comparison with available literature data. Its equivalence with Bragg-Gray cavity theory was demonstrated mathematically. The capability of GATE-RTion v1.0 for the sw,det calculation at any point of a 3D dose distribution for simple and complex proton and carbon ion plans was presented.
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Affiliation(s)
- Marta Bolsa-Ferruz
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria
| | - Hugo Palmans
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria.,Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, UK
| | - David Boersma
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria.,ACMIT Gmbh, Viktor-Kaplan-Straße 2/1, Wiener Neustadt, A-2700, Austria
| | - Markus Stock
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria
| | - Loïc Grevillot
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria
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27
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Sarrut D, Etxebeste A, Krah N, Létang JM. Modeling complex particles phase space with GAN for Monte Carlo SPECT simulations: a proof of concept. Phys Med Biol 2021; 66:055014. [PMID: 33477121 DOI: 10.1088/1361-6560/abde9a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A method is proposed to model by a generative adversarial network the distribution of particles exiting a patient during Monte Carlo simulation of emission tomography imaging devices. The resulting compact neural network is then able to generate particles exiting the patient, going towards the detectors, avoiding costly particle tracking within the patient. As a proof of concept, the method is evaluated for single photon emission computed tomography (SPECT) imaging and combined with another neural network modeling the detector response function (ARF-nn). A complete rotating SPECT acquisition can be simulated with reduced computation time compared to conventional Monte Carlo simulation. It also allows the user to perform simulations with several imaging systems or parameters, which is useful for imaging system design.
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Affiliation(s)
- D Sarrut
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard 69373, France
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28
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Younes T, Chauvin M, Delbaere A, Labour J, Fonteny V, Simon L, Fares G, Vieillevigne L. Towards the standardization of the absorbed dose report mode in high energy photon beams. Phys Med Biol 2021; 66:045009. [PMID: 33296874 DOI: 10.1088/1361-6560/abd22c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The benefits of using an algorithm that reports absorbed dose-to-medium have been jeopardized by the clinical experience and the experimental protocols that have mainly relied on absorbed dose-to-water. The aim of the present work was to investigate the physical aspects that govern the dosimetry in heterogeneous media using Monte Carlo method and to introduce a formalism for the experimental validation of absorbed dose-to-medium reporting algorithms. Particle fluence spectra computed within the sensitive volume of two simulated detectors (T31016 Pinpoint 3D ionization chamber and EBT3 radiochromic film) placed in different media (water, RW3, lung and bone) were compared to those in the undisturbed media for 6 MV photon beams. A heterogeneity correction factor that takes into account the difference between the detector perturbation in medium and under reference conditions as well as the stopping-power ratios was then derived for all media using cema calculations. Furthermore, the different conversion approaches and Eclipse treatment planning system algorithms were compared against the Monte Carlo absorbed dose reports. The detectors electron fluence perturbation in RW3 and lung media were close to that in water (≤1.5%). However, the perturbation was greater in bone (∼4%) and impacted the spectral shape. It was emphasized that detectors readings should be corrected by the heterogeneity correction factor that ranged from 0.932 in bone to 0.985 in lung. Significant discrepancies were observed between all the absorbed dose reports and conversions, especially in bone (exceeding 10%) and to a lesser extent in RW3. Given the ongoing advances in dose calculation algorithms, it is essential to standardize the absorbed dose report mode with absorbed dose-to-medium as a favoured choice. It was concluded that a retrospective conversion should be avoided and switching from absorbed dose-to-water to absorbed dose-to-medium reporting algorithm should be carried out by a direct comparison of both algorithms.
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Affiliation(s)
- Tony Younes
- Department of Medical Physics, Institut Claudius Regaud-Institut Universitaire du Cancer de Toulouse Oncopole, 1 avenue Irène Joliot Curie, F-31059 Toulouse Cedex 9, France. Centre de Recherche et de Cancérologie de Toulouse, UMR1037 INSERM-Université Toulouse 3-ERL5294 CNRS, 2 avenue Hubert Curien, F-31037 Toulouse Cedex 1, France. Laboratoire de 'Mathématiques et Applications', Unité de recherche 'Mathématiques et Modélisation', Centre d'analyses et de recherche, Faculté des sciences, Université Saint-Joseph, Beyrouth 1104 2020, Lebanon
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29
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Tegaw EM, Geraily G, Etesami SM, Gholami S, Ghanbari H, Farzin M, Tadesse GF, Shojaei M. A Comparison between Electron Gamma Shower, National Research Council/Easy Particle Propagation (EGSnrc/Epp) and Monte Carlo N-Particle Transport Code (MCNP) in Simulation of the INTRABEAM ® System with Spherical Applicators. J Biomed Phys Eng 2021; 11:47-54. [PMID: 33564639 PMCID: PMC7859382 DOI: 10.31661/jbpe.v0i0.2008-1171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/05/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Online Monte Carlo (MC) treatment planning is very crucial to increase the precision of intraoperative radiotherapy (IORT). However, the performance of MC methods depends on the geometries and energies used for the problem under study. OBJECTIVE This study aimed to compare the performance of MC N-Particle Transport Code version 4c (MCNP4c) and Electron Gamma Shower, National Research Council/easy particle propagation (EGSnrc/Epp) MC codes using similar geometry of an INTRABEAM® system. MATERIAL AND METHODS This simulation study was done by increasing the number of particles and compared the performance of MCNP4c and EGSnrc/Epp simulations using an INTRABEAM® system with 1.5 and 5 cm diameter spherical applicators. A comparison of these two codes was done using simulation time, statistical uncertainty, and relative depth-dose values obtained after doing the simulation by each MC code. RESULTS The statistical uncertainties for the MCNP4c and EGSnrc/Epp MC codes were below 2% and 0.5%, respectively. 1e9 particles were simulated in 117.89 hours using MCNP4c but a much greater number of particles (5e10 particles) were simulated in a shorter time of 90.26 hours using EGSnrc/Epp MC code. No significant deviations were found in the calculated relative depth-dose values for both in the presence and absence of an air gap between MCNP4c and EGSnrc/Epp MC codes. Nevertheless, the EGSnrc/Epp MC code was found to be speedier and more efficient to achieve accurate statistical precision than MCNP4c. CONCLUSION Therefore, in all comparisons criteria used, EGSnrc/Epp MC code is much better than MCNP4c MC code for simulating an INTRABEAM® system.
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Affiliation(s)
- E. M. Tegaw
- PhD, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
- PhD, Department of Physics, Faculty of Natural and Computational Sciences, Debre Tabor University, Debre Tabor, Ethiopia
| | - Gh. Geraily
- PhD, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
- PhD, Radiation Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - S. M. Etesami
- PhD, School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
| | - S. Gholami
- PhD, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
- PhD, Radiation Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - H. Ghanbari
- PhD, Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - M. Farzin
- PhD, Radiation Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
- PhD, Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - G. F. Tadesse
- PhD, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
- PhD, Department of Physics, College of Natural and Computational Sciences, Aksum University, Ethiopia
| | - M. Shojaei
- PhD, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
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Clemente S, Falco MD, Cagni E, Talamonti C, Boccia M, Gino E, Lorenzini E, Rosica F, Russo S, Alparone A, Zefiro D, Fiandra C. The influence of small field output factors simulated uncertainties on the calculated dose in VMAT plans for brain metastases: a multicentre study. Br J Radiol 2021; 94:20201354. [PMID: 33481637 DOI: 10.1259/bjr.20201354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES This multicentric study was carried out to investigate the impact of small field output factors (OFs) inaccuracies on the calculated dose in volumetric arctherapy (VMAT) radiosurgery brain plans. METHODS Nine centres, realised the same five VMAT plans with common planning rules and their specific clinical equipment Linac/treatment planning system commissioned with their OFs measured values (OFbaseline). In order to simulate OFs errors, two new OFs sets were generated for each centre by changing only the OFs values of the smallest field sizes (from 3.2 × 3.2 cm2 to 1 × 1 cm2) with well-defined amounts (positive and negative). Consequently, two virtual machines for each centre were recommissioned using the new OFs and the percentage dose differences ΔD (%) between the baseline plans and the same plans recalculated using the incremented (OFup) and decremented (OFdown) values were evaluated. The ΔD (%) were analysed in terms of planning target volume (PTV) coverage and organs at risk (OARs) sparing at selected dose/volume points. RESULTS The plans recalculated with OFdown sets resulted in higher variation of doses than baseline within 1.6 and 3.4% to PTVs and OARs respectively; while the plans with OFup sets resulted in lower variation within 1.3% to both PTVs and OARs. Our analysis highlights that OFs variations affect calculated dose depending on the algorithm and on the delivery mode (field jaw/MLC-defined). The Monte Carlo (MC) algorithm resulted significantly more sensitive to OFs variations than all of the other algorithms. CONCLUSION The aim of our study was to evaluate how small fields OFs inaccuracies can affect the dose calculation in VMAT brain radiosurgery treatments plans. It was observed that simulated OFs errors, return dosimetric calculation accuracies within the 3% between concurrent plans analysed in terms of percentage dose differences at selected dose/volume points of the PTV coverage and OARs sparing. ADVANCES IN KNOWLEDGE First multicentre study involving different Planning/Linacs about undetectable errors in commissioning output factor for small fields.
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Affiliation(s)
- Stefania Clemente
- Unit of Medical Physics and Radioprotection, Federico II University Hospital, Napoli, Italy
| | - Maria Daniela Falco
- Department of Radiation Oncology, "G. D'Annunzio" University, "SS. Annunziata" Hospital, Chieti, Italy
| | - Elisabetta Cagni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Cinzia Talamonti
- Medical Physics Unit, University Of Florence, Azienda Ospedaliero Universitaria Careggi, Florence, Italy
| | | | - Eva Gino
- Medical PhysicDepartment, A.O. Ordine Mauriziano, Turin, Italy
| | - Elena Lorenzini
- U.O.C Fisica Sanitaria Area Nord, Azienda USL Nord Ovest Toscana, Massa Carrara, Italy
| | | | | | | | - Daniele Zefiro
- MedicaPhysics Unit, ASL5 Sistema Sanitario Regione Liguria, La Spezia, Italy
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31
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Romero M, Macchione MA, Mattea F, Strumia M. The role of polymers in analytical medical applications. A review. Microchem J 2020. [DOI: 10.1016/j.microc.2020.105366] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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32
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Lam SE, Noor NM, Bradley DA, Mahmud R, Pawanchek M, Abdul Rashid HA. Small-field output ratio determination using 6 mol% Ge-doped silica fibre dosimeters. Biomed Phys Eng Express 2020; 6. [PMID: 35042836 DOI: 10.1088/2057-1976/abc2a4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/19/2020] [Indexed: 11/12/2022]
Abstract
This work investigates the suitability of locally fabricated 6 mol% Ge-doped optical fibres as dosimeters for small-field output ratio measurements. Two fabrications of fibre, cylindrical (CF) and flat (FF) fibres, were used to measure doses in small photon fields, from 4 to 15 mm. The findings were compared to those of commercial Ge-doped fibre (COMM), EBT3 film and an IBA CC01 ionization chamber. Irradiations were carried out using a 6 MV SRS photon beam operating at a dose rate of 1000 cGy min-1, delivering a dose of 16 Gy. To minimise the possibility of the fibres failing to be exposed to the intended dose in small fields, the fibres were accommodated in a custom-made Perspex phantom. For the 4 mm cone the CF and FF measured output ratios were found to be smaller than obtained with EBT3 film by 32% and 13% respectively. Conversely, while for the 6 to 15 mm cone fields the FF output ratios were consistently greater than those obtained using EBT3 film, the CF output ratios differed from those of EBT3 film by at most 3.2%, at 6 mm, otherwise essentially agreeing with EBT3 values at the other field sizes. For the 4 to 7.5 mm cones, all output ratios obtained from Ge-doped optical fibre measurements were greater than those of IBA CC01 ionization chamber. The measured FF and CF output ratios for the 7.5 to 15 mm cones agreed with published MC estimates to within 15% and 13%, respectively. Down to 6 mm cone field, present measurements point to the potential of CF as a small-field dosimeter, its use recommended to be complemented by the use of EBT3 film for small-field dosimetry.
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Affiliation(s)
- S E Lam
- Centre for Biomedical Physics, School of Healthcare and Medical Sciences, Sunway University, 47500 Petaling Jaya, Selangor, Malaysia.,Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - N Mohd Noor
- Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.,Department of Radiology, Teaching Hospital Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - D A Bradley
- Centre for Biomedical Physics, School of Healthcare and Medical Sciences, Sunway University, 47500 Petaling Jaya, Selangor, Malaysia.,Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - R Mahmud
- Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.,Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - M Pawanchek
- Department of Radiotherapy and Oncology, National Cancer Institute, 62250 W.P. Putrajaya, Malaysia
| | - H A Abdul Rashid
- Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor, Malaysia
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Abolaban FA, Taha EM. Representation and illustration of the initial parameters in GATE 8.1 monte carlo simulation of an Elekta Versa-HD linear accelerator. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2020. [DOI: 10.1080/16878507.2020.1820271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Fouad A. Abolaban
- King Abdulaziz University, College of Engineering, Nuclear Engineering Department, Jeddah, Kingdom of Saudi Arabia, Jeddah, Saudi Arabia
| | - Eslam M. Taha
- King Abdulaziz University, College of Engineering, Nuclear Engineering Department, Jeddah, Kingdom of Saudi Arabia, Jeddah, Saudi Arabia
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34
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Whole-body voxel-based internal dosimetry using deep learning. Eur J Nucl Med Mol Imaging 2020; 48:670-682. [PMID: 32875430 PMCID: PMC8036208 DOI: 10.1007/s00259-020-05013-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/23/2020] [Indexed: 12/20/2022]
Abstract
Purpose In the era of precision medicine, patient-specific dose calculation using Monte Carlo (MC) simulations is deemed the gold standard technique for risk-benefit analysis of radiation hazards and correlation with patient outcome. Hence, we propose a novel method to perform whole-body personalized organ-level dosimetry taking into account the heterogeneity of activity distribution, non-uniformity of surrounding medium, and patient-specific anatomy using deep learning algorithms. Methods We extended the voxel-scale MIRD approach from single S-value kernel to specific S-value kernels corresponding to patient-specific anatomy to construct 3D dose maps using hybrid emission/transmission image sets. In this context, we employed a Deep Neural Network (DNN) to predict the distribution of deposited energy, representing specific S-values, from a single source in the center of a 3D kernel composed of human body geometry. The training dataset consists of density maps obtained from CT images and the reference voxelwise S-values generated using Monte Carlo simulations. Accordingly, specific S-value kernels are inferred from the trained model and whole-body dose maps constructed in a manner analogous to the voxel-based MIRD formalism, i.e., convolving specific voxel S-values with the activity map. The dose map predicted using the DNN was compared with the reference generated using MC simulations and two MIRD-based methods, including Single and Multiple S-Values (SSV and MSV) and Olinda/EXM software package. Results The predicted specific voxel S-value kernels exhibited good agreement with the MC-based kernels serving as reference with a mean relative absolute error (MRAE) of 4.5 ± 1.8 (%). Bland and Altman analysis showed the lowest dose bias (2.6%) and smallest variance (CI: − 6.6, + 1.3) for DNN. The MRAE of estimated absorbed dose between DNN, MSV, and SSV with respect to the MC simulation reference were 2.6%, 3%, and 49%, respectively. In organ-level dosimetry, the MRAE between the proposed method and MSV, SSV, and Olinda/EXM were 5.1%, 21.8%, and 23.5%, respectively. Conclusion The proposed DNN-based WB internal dosimetry exhibited comparable performance to the direct Monte Carlo approach while overcoming the limitations of conventional dosimetry techniques in nuclear medicine.
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35
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Prabhu S, Bubbly SG, Gudennavar SB. Synthetic polymer hydrogels as potential tissue phantoms in radiation therapy and dosimetry. Biomed Phys Eng Express 2020; 6:055008. [PMID: 33444239 DOI: 10.1088/2057-1976/aba209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The efficacy of synthetic polymers as hydrogel phantoms for radiation therapy and dosimetry has been investigated for photon and charged particle (electron, proton and alpha particle) interactions. Tissue equivalence has been studied in terms of photon mass energy-absorption coefficients, KERMA (kinetic energy released per unit mass), equivalent atomic number and energy absorption build-up factors, relative to human tissues (skin, soft tissue, cortical bone and skeletal muscle), in the energy range 0.015-15 MeV. For charged particle interactions, ratio of effective atomic number is examined for tissue-equivalence in the energy region of 10 keV-1 GeV. Well established theoretical formulations are used for computation of photon mass-energy absorption effective atomic number, electron density and KERMA. Five-parameter geometric progression (G-P) fitting approximation is used to compute the values of energy absorption build-up factors. Effective atomic number for charged particle interaction is determined using logarithmic interpolation method. Using the analytical methodology, it has been revealed that all the selected synthetic polymers have good tissue-equivalence relative to all tissue except cortical bone. In particular, polyglycolic acid (PGA) and poly-lactic-co-glycolic acid (PLGA) prove to be best substitute material for photon interactions. On the other hand, % difference between effective atomic number for charged particle relative to human tissues is found least for polyethylene glycol (PEG) demonstrating adequate tissue-equivalence. Therefore, the present study is expected to be useful to choose most appropriate phantom material for radiation therapy.
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Affiliation(s)
- Srilakshmi Prabhu
- Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore Central Campus, Bengaluru - 560029, Karnataka, India
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A general-purpose Monte Carlo particle transport code based on inverse transform sampling for radiotherapy dose calculation. Sci Rep 2020; 10:9808. [PMID: 32555530 PMCID: PMC7300009 DOI: 10.1038/s41598-020-66844-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 05/27/2020] [Indexed: 02/04/2023] Open
Abstract
The Monte Carlo (MC) method is widely used to solve various problems in radiotherapy. There has been an impetus to accelerate MC simulation on GPUs whereas thread divergence remains a major issue for MC codes based on acceptance-rejection sampling. Inverse transform sampling has the potential to eliminate thread divergence but it is only implemented for photon transport. Here, we report a MC package Particle Transport in Media (PTM) to demonstrate the implementation of coupled photon-electron transport simulation using inverse transform sampling. Rayleigh scattering, Compton scattering, photo-electric effect and pair production are considered in an analogous manner for photon transport. Electron transport is simulated in a class II condensed history scheme, i.e., catastrophic inelastic scattering and Bremsstrahlung events are simulated explicitly while subthreshold interactions are subject to grouping. A random-hinge electron step correction algorithm and a modified PRESTA boundary crossing algorithm are employed to improve simulation accuracy. Benchmark studies against both EGSnrc simulations and experimental measurements are performed for various beams, phantoms and geometries. Gamma indices of the dose distributions are better than 99.6% for all the tested scenarios under the 2%/2 mm criteria. These results demonstrate the successful implementation of inverse transform sampling in coupled photon-electron transport simulation.
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Talaat K, Xi J, Baldez P, Hecht A. Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung. Sci Rep 2019; 9:17450. [PMID: 31768010 PMCID: PMC6877642 DOI: 10.1038/s41598-019-54040-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/08/2019] [Indexed: 11/18/2022] Open
Abstract
Despite extensive efforts in studying radioactive aerosols, including the transmission of radionuclides in different chemical matrices throughout the body, the internal organ-specific radiation dose due to inhaled radioactive aerosols has largely relied on experimental deposition data and simplified human phantoms. Computational fluid-particle dynamics (CFPD) has proven to be a reliable tool in characterizing aerosol transport in the upper airways, while Monte Carlo based radiation codes allow accurate simulation of radiation transport. The objective of this study is to numerically assess the radiation dosimetry due to particles decaying in the respiratory tract from environmental radioactive exposures by coupling CFPD with Monte Carlo N-Particle code, version 6 (MCNP6). A physiologically realistic mouth-lung model extending to the bifurcation generation G9 was used to simulate airflow and particle transport within the respiratory tract. Polydisperse aerosols with different distributions were considered, and deposition distribution of the inhaled aerosols on the internal airway walls was quantified. The deposition mapping of radioactive aerosols was then registered to the respiratory tract of an image-based whole-body adult male model (VIP-Man) to simulate radiation transport and energy deposition. Computer codes were developed for geometry visualization, spatial normalization, and source card definition in MCNP6. Spatial distributions of internal radiation dosimetry were compared for different radionuclides (131I, 134,137Cs, 90Sr-90Y, 103Ru and 239,240Pu) in terms of the radiation fluence, energy deposition density, and dose per decay.
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Affiliation(s)
- Khaled Talaat
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Jinxiang Xi
- Department of Mechanical and Biomedical Engineering, California Baptist University, Riverside, CA, 92504, USA. .,Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, 01854, USA.
| | - Phoenix Baldez
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Adam Hecht
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, NM, 87131, USA
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Delbaere A, Younes T, Vieillevigne L. On the conversion from dose-to-medium to dose-to-water in heterogeneous phantoms with Acuros XB and Monte Carlo calculations. ACTA ACUST UNITED AC 2019; 64:195016. [DOI: 10.1088/1361-6560/ab3df3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Arbor N, Gasteuil J, Noblet C, Moreau M, Meyer P. A GATE/Geant4 Monte Carlo toolkit for surface dose calculation in VMAT breast cancer radiotherapy. Phys Med 2019; 61:112-117. [PMID: 31036441 DOI: 10.1016/j.ejmp.2019.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/09/2019] [Accepted: 04/15/2019] [Indexed: 10/26/2022] Open
Abstract
The accuracy of superficial dose calculations for breast cancer treatments with Volumetric Modulated Arc Therapy (VMAT) is of major importance. For target volumes close to the surface, the inverse dosimetric planning can lead to very high fluences in the build-up region to properly cover the volume to be treated. Various radiotherapy modalities are currently used in parallel with additional protocols to enable a better control on the dose delivery (bolus, target volume margins). One of the difficulties currently facing medical physicists is the lack of available tools to test the impact of these different solutions on the superficial dose distribution. We present a new open source toolkit to assist medical physicists in evaluating the 3D distributions of superficial dose in VMAT breast cancer treatments. This tool is based on the GATE Monte Carlo software, a Geant4 application dedicated to medical physics. A set of macros has been developed to simulate in an easy way a full VMAT plan from the information available in the DICOM-RT files (image, plan, structure and dose). The toolkit has been tested on a 6 MV Varian NovalisTx™ accelerator. The paper presents a precise comparison of 3D surface dose distributions from experimental measurements (EBT3 films), TPS (Varian Eclipse) and Monte Carlo simulation (GATE). The comparison made it possible to highlight both the TPS biases for the surface dose calculation and the good performances of the developed toolkit. The simulation of surface dose distributions on a real patient has also been performed to illustrate the potential clinical applications.
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Affiliation(s)
- Nicolas Arbor
- Université de Strasbourg, IPHC, 23 rue du Loess, 67037 Strasbourg, France; CNRS, UMR7178, 67037 Strasbourg, France.
| | - Jean Gasteuil
- Division of Medical Physics, Department of Radiotherapy, Paul Strauss Center, Strasbourg, France
| | - Caroline Noblet
- Division of Medical Physics, Department of Radiotherapy, Paul Strauss Center, Strasbourg, France
| | - Matthieu Moreau
- Division of Medical Physics, Department of Radiotherapy, Paul Strauss Center, Strasbourg, France
| | - Philippe Meyer
- Division of Medical Physics, Department of Radiotherapy, Paul Strauss Center, Strasbourg, France
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Brualla L, Rodriguez M, Sempau J, Andreo P. PENELOPE/PRIMO-calculated photon and electron spectra from clinical accelerators. Radiat Oncol 2019; 14:6. [PMID: 30634994 PMCID: PMC6330451 DOI: 10.1186/s13014-018-1186-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/19/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The availability of photon and electron spectra in digital form from current accelerators and Monte Carlo (MC) systems is scarce, and one of the packages widely used refers to linacs with a reduced clinical use nowadays. Such spectra are mainly intended for the MC calculation of detector-related quantities in conventional broad beams, where the use of detailed phase-space files (PSFs) is less critical than for MC-based treatment planning applications, but unlike PSFs, spectra can easily be transferred to other computer systems and users. METHODS A set of spectra for a range of Varian linacs has been calculated using the PENELOPE/PRIMO MC system. They have been extracted from PSFs tallied for field sizes of 10 cm × 10 cm and 15 cm × 15 cm for photon and electron beams, respectively. The influence of the spectral bin width and of the beam central axis region used to extract the spectra have been analyzed. RESULTS Spectra have been compared to those by other authors showing good agreement with those obtained using the, now superseded, EGS4/BEAM MC code, but significant differences with the most widely used photon data set. Other spectra, particularly for electron beams, have not been published previously for the machines simulated in this work. The influence of the bin width on the spectrum mean energy for 6 and 10 MV beams has been found to be negligible. The size of the region used to extract the spectra yields differences of up to 40% for the mean energies in 10 MV beams, but the maximum difference for TPR 20,10 values derived from depth-dose distributions does not exceed 2% relative to those obtained using the PSFs. This corresponds to kQ differences below 0.2% for a typical Farmer-type chamber, considered to be negligible for reference dosimetry. Different configurations for using electron spectra have been compared for 6 MeV beams, concluding that the geometry used for tallying the PSFs used to extract the spectra must be accounted for in subsequent calculations using the spectra as a source. CONCLUSIONS An up-to-date set of consistent spectra for Varian accelerators suitable for the calculation of detector-related quantities in conventional broad beams has been developed and made available in digital form.
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Affiliation(s)
- Lorenzo Brualla
- West German Proton Therapy Centre Essen (WPE), Essen, D-45147, Germany. .,West German Cancer Center (WTZ), Essen, D-45147, Germany. .,University Hospital Essen, Essen, D-45147, Germany. .,Universität Duisburg-Essen, Medizinische Fakultät, Essen, D-45147, Germany.
| | - Miguel Rodriguez
- Centro Médico Paitilla, Panama City, 0816-03075, Panama.,Instituto de Investigaciones Científicas y de Alta Tecnología, INDICASAT-AIP, City of Knowledge, Building 219, Panama City, Panama
| | - Josep Sempau
- Department of Physics and Institute of Energy Technologies, Universitat Politècnica de Catalunya, Barcelona, E-08028, Spain
| | - Pedro Andreo
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, and Department of Oncology-Pathology, Karolinska Institutet, Stockholm, SE-171 76, Sweden
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