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B G A, Bentefour EH, Teo BKK, Samuel D. A comparative study of machine-learning approaches in proton radiography using energy-resolved dose function. Phys Med 2023; 106:102525. [PMID: 36621081 DOI: 10.1016/j.ejmp.2023.102525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 12/28/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023] Open
Abstract
PURPOSE The feasibility of machine learning (ML) techniques and their performance compared to the conventional χ2-minimization technique in the context of the proton energy-resolved dose imaging method are presented. MATERIALS AND METHOD Various geometries resembling a wedge and varying gradients are simulated in GATE to obtain energy-resolved dose functions (ERDF) from proton beams of different energies. These ERDFs are used to predict the WEPL using a conventional technique and other ML-based methods. The results are compared to gain an understanding of the performance of ML models in proton radiography. RESULTS The results obtained from the χ2-minimization technique indicate that it is robust and more reliable compared to the ML-based techniques. It is also observed that the ML-based techniques did not mitigate the effect of range-mixing but seem to be more affected by it compared to the χ2-minimization technique. Substantial data reduction was required in order to make the results of ML-based methods comparable to that of χ2-minimization. We also note that such data reduction might not be possible in a clinical setting. The only advantage in using the ML-based technique is the computational time required to generate a WEPL map which, in our case study, is 10-30 times shorter than the time required for the conventional χ2-minimization technique. CONCLUSIONS The first results from this preliminary study indicate that the ML techniques failed to be on par with the conventional χ2-minimization technique in terms of the achievable accuracy in the predictions of WEPL and in the mitigation of range-mixing effects in the WEPL image. Modern strategies like the GAN-based models may be suitable for such applications.
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Affiliation(s)
- Alaka B G
- Department of Physics, Central University of Karnataka, Kalaburagi, 585367, Karnataka, India.
| | - El H Bentefour
- Veritas Medical Solutions inc, Cassell Rd, Harleysville, 19438, PA, USA
| | - Boon-Keng Kevin Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Deepak Samuel
- Department of Physics, Central University of Karnataka, Kalaburagi, 585367, Karnataka, India
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Cui X, Jee K, Hu M, Bao J, Lu HM. Improvement of proton beam range uncertainty in breast treatment using tissue samples. Phys Med Biol 2022; 67. [PMID: 36379067 DOI: 10.1088/1361-6560/aca315] [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: 06/08/2022] [Accepted: 11/15/2022] [Indexed: 11/16/2022]
Abstract
Objective.Proton therapy after breast-conserving surgery (BCS) can substantially reduce the dose to lung and cardiac structures. However, these dosimetric benefits are subject to beam range uncertainty in patient. The conversion of the CT-Hounsfield unit (HU) into relative stopping power (RSP) is the primary contribution to range uncertainty. Hence, an accurate HU-RSP conversion is essential.Approach.Real tissue samples, including muscle and adipose, were prepared. The water equivalent path length (WEPL) of these samples was measured under homogeneous conditions using a 12-diode detector array of our time-resolvedin vivorange verification system (IRVS). The HU-RSP conversion was improved using the measured WEPL and HU for adipose tissue. The measured WEPL values were compared with the treatment planning calculation results based on the stoichiometric CT-HU calibration technique. The effect was investigated for both with and without adipose tissue in HU-RSP conversion.Main results.The IRVS was calibrated based on the solid water phantom. The relative differences in WEPL (RSP) between measurements and calculations for muscle, adipose, and water was -1.19% (-0.75%), -4.25%(-4%), and -0.23%(-0.07%), respectively. Based on the improved HU-RSP conversion, the relative differences in WEPL was reduced to -0.97%(-0.62%), -1.50%(-1.46%), and -0.22% (0.00%), respectively.Significance.The WEPL deviation of adipose tissue is larger than the testing limit of 3.5% for beam range robustness in current clinical practice. However, the improved HU-RSP conversion reduced this deviation. The main component of breast tissue is adipose. Hence, the proton treatment of BCS can be undershooting if no proper measures are taken against this specific uncertainty.
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Affiliation(s)
- Xiangli Cui
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, 230031, People's Republic of China.,Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei, Anhui, 230031, People's Republic of China
| | - Kyungwook Jee
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, United States of America
| | - Man Hu
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, 250117, People's Republic of China
| | - Jie Bao
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, 230031, People's Republic of China
| | - Hsiao-Ming Lu
- Hefei Ion Medical Center, Hefei, Anhui, 230088, People's Republic of China
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Freitas H, Magalhaes Martins P, Tessonnier T, Ackermann B, Brons S, Seco J. Dataset for predicting single-spot proton ranges in proton therapy of prostate cancer. Sci Data 2021; 8:252. [PMID: 34588458 PMCID: PMC8481263 DOI: 10.1038/s41597-021-01028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 08/05/2021] [Indexed: 11/09/2022] Open
Abstract
The number of radiotherapy patients treated with protons has increased from less than 60,000 in 2007 to more than 220,000 in 2019. However, the considerable uncertainty in the positioning of the Bragg peak deeper in the patient raised new challenges in the proton therapy of prostate cancer (PCPT). Here, we describe and share a dataset where 43 single-spot anterior beams with defined proton energies were delivered to a prostate phantom with an inserted endorectal balloon (ERB) filled either with water only or with a silicon-water mixture. The nuclear reactions between the protons and the silicon yield a distinct prompt gamma energy line of 1.78 MeV. Such energy peak could be identified by means of prompt gamma spectroscopy (PGS) for the protons hitting the ERB with a three-sigma threshold. The application of a background-suppression technique showed an increased rejection capability for protons hitting the prostate and the ERB with water only. We describe each dataset, document the full processing chain, and provide the scripts for the statistical analysis.
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Affiliation(s)
- Hugo Freitas
- German Cancer Research Center - DKFZ, Heidelberg, Germany
- Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Paulo Magalhaes Martins
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal.
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Benjamin Ackermann
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joao Seco
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
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Lucconi G, Bentefour EH, Samuel D, Weaver K, Moteabbed M, Lu HM. In-vivo proton range verification for reducing the risk of permanent alopecia in medulloblastoma treatment. RADIATION MEDICINE AND PROTECTION 2021. [DOI: 10.1016/j.radmp.2021.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Magalhaes Martins P, Freitas H, Tessonnier T, Ackermann B, Brons S, Seco J. Towards real-time PGS range monitoring in proton therapy of prostate cancer. Sci Rep 2021; 11:15331. [PMID: 34321492 PMCID: PMC8319377 DOI: 10.1038/s41598-021-93612-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 06/24/2021] [Indexed: 11/09/2022] Open
Abstract
Proton therapy of prostate cancer (PCPT) was linked with increased levels of gastrointestinal toxicity in its early use compared to intensity-modulated radiation therapy (IMRT). The higher radiation dose to the rectum by proton beams is mainly due to anatomical variations. Here, we demonstrate an approach to monitor rectal radiation exposure in PCPT based on prompt gamma spectroscopy (PGS). Endorectal balloons (ERBs) are used to stabilize prostate movement during radiotherapy. These ERBs are usually filled with water. However, other water solutions containing elements with higher atomic numbers, such as silicon, may enable the use of PGS to monitor the radiation exposure of the rectum. Protons hitting silicon atoms emit prompt gamma rays with a specific energy of 1.78 MeV, which can be used to monitor whether the ERB is being hit. In a binary approach, we search the silicon energy peaks for every irradiated prostate region. We demonstrate this technique for both single-spot irradiation and real treatment plans. Real-time feedback based on the ERB being hit column-wise is feasible and would allow clinicians to decide whether to adapt or continue treatment. This technique may be extended to other cancer types and organs at risk, such as the oesophagus.
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Affiliation(s)
- Paulo Magalhaes Martins
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.
| | - Hugo Freitas
- German Cancer Research Center - DKFZ, Heidelberg, Germany
- Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Benjamin Ackermann
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joao Seco
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
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Paganetti H, Beltran C, Both S, Dong L, Flanz J, Furutani K, Grassberger C, Grosshans DR, Knopf AC, Langendijk JA, Nystrom H, Parodi K, Raaymakers BW, Richter C, Sawakuchi GO, Schippers M, Shaitelman SF, Teo BKK, Unkelbach J, Wohlfahrt P, Lomax T. Roadmap: proton therapy physics and biology. Phys Med Biol 2021; 66. [DOI: 10.1088/1361-6560/abcd16] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022]
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Alaka BG, Bentefour EH, Chirvase C, Samuel D, Teo BKK. Feasibility of energy-resolved dose imaging technique in pencil beam scanning mode. Biomed Phys Eng Express 2020; 6. [PMID: 35102004 DOI: 10.1088/2057-1976/abb4ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/03/2020] [Indexed: 11/11/2022]
Abstract
Purpose:Proton energy-resolved dose imaging (pERDI) is a recently proposed technique to generate water equivalent path length (WEPL) images using a single detector. Owing to its simplicity in instrumentation, analysis and the possibility of using the in-room x-ray flat panels as detectors, this technique offers a promising avenue towards a clinically usable imaging system for proton therapy using scanned beams. The purpose of this study is to estimate the achievable accuracy in WEPL and Relative Stopping Power (RSP) using the pERDI technique and to assess the minimum dose required to achieve such accuracy. The novelty of this study is the first demonstration of the feasibility of pERDI technique in the pencil beam scanning (PBS) mode.Methods:A solid water wedge was placed in front of a 2D detector (Lynx). A library of energy-resolved dose functions (ERDF) was generated from the dose deposited in the detector by 50 PBS layers of energy varying from 100 MeV to 225 MeV. This set-up is further used to image the following configurations using the pERDI technique: stair-case shaped solid water phantom (configuration 1), electron density phantom (configuration 2) and head phantom (configuration 3). The result from configuration 1 was used to determine the achievable WEPL accuracy. The result from configuration 2 was used to estimate the relative uncertainty in RSP. Configuration 3 was used to evaluate the effect of range mixing on the WEPL. In all three cases, the variation of the accuracy with respect to dose, by varying the number of scanning layers, was also studied.Results:An accuracy of 1 mm in WEPL was achieved using the Lynx detector with an imaging field of 10 PBS layers or more, which is equivalent to a total dose of 5 cGy. The RSP is measured with a precision better than 2% for all homogeneous inserts of tissue surrogates. The pERDI technique failed for tissues surrogates with total WEPL outside the calibration window (WEPL < 70 mm) like in the case of lung exhale and lung inhale. The imaging of an anthropomorphic head phantom, in the same condition, produced a WEPL radiograph and compared to the WEPL derived from CT using gamma index analysis. The gamma index failed in the heterogeneous areas due to range mixing.Conclusions:The pERDI technique is a promising clinically usable imaging modality for reducing range uncertainties and set-up errors in proton therapy. The first results have demonstrated that WEPL and RSP can be estimated with clinically acceptable accuracy using the Lynx detector. Similar accuracy is also expected with in-room flat-panel detectors but at significantly reduced imaging dose. Though the issue of range mixing is still to be addressed, we expect that a statistical moment analysis of the ERDFs can be implemented to filter out the regions with high gradient of range mixing.
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Affiliation(s)
- B G Alaka
- Department of Physics, Central University of Karnataka, Kalaburgi, Karnataka, India
| | - El H Bentefour
- University of Maryland School of Medicine, Proton Therapy Cancer Treatment Center, United States of America
| | | | - Deepak Samuel
- Department of Physics, Central University of Karnataka, Kalaburgi, Karnataka, India
| | - Boon-Keng Kevin Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States of America
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Albertini F, Matter M, Nenoff L, Zhang Y, Lomax A. Online daily adaptive proton therapy. Br J Radiol 2020; 93:20190594. [PMID: 31647313 PMCID: PMC7066958 DOI: 10.1259/bjr.20190594] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/15/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022] Open
Abstract
It is recognized that the use of a single plan calculated on an image acquired some time before the treatment is generally insufficient to accurately represent the daily dose to the target and to the organs at risk. This is particularly true for protons, due to the physical finite range. Although this characteristic enables the generation of steep dose gradients, which is essential for highly conformal radiotherapy, it also tightens the dependency of the delivered dose to the range accuracy. In particular, the use of an outdated patient anatomy is one of the most significant sources of range inaccuracy, thus affecting the quality of the planned dose distribution. A plan should be ideally adapted as soon as anatomical variations occur, ideally online. In this review, we describe in detail the different steps of the adaptive workflow and discuss the challenges and corresponding state-of-the art developments in particular for an online adaptive strategy.
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Affiliation(s)
| | | | | | - Ye Zhang
- Paul Scherrer Institute, Center for Proton Therapy, Switzerland
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9
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Doolan PJ, Bentefour EH, Testa M, Cascio E, Sharp G, Royle G, Lu HM. Higher order analysis of time-resolved proton radiographs. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab36ea] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Smith BR, Pankuch M, Hammer CG, DeWerd LA, Culberson WS. LET response variability of Gafchromic TM EBT3 film from a 60 Co calibration in clinical proton beam qualities. Med Phys 2019; 46:2716-2728. [PMID: 30740699 DOI: 10.1002/mp.13442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/01/2019] [Accepted: 02/02/2019] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To establish a method of accurate dosimetry required to quantify the expected linear energy transfer (LET) quenching effect of EBT3 film used to benchmark the dose distribution for a given treatment field and specified measurement depth. In order to facilitate this technique, a full analysis of film calibration which considers LET variability at the plane of measurement and as a function of proton beam quality is demonstrated. Additionally, the corresponding uncertainty from the process was quantified for several measurement scenarios. MATERIALS AND METHODS The net change in optical density (OD) from a single version of Gafchromic TM EBT3 film was measured using an Epson flatbed scanner and NIST-traceable OD filters. Film OD response was characterized with respect to the known dose to water at the point of measurement for both a NIST-traceable 60 Co beam at the UWADCL and several clinical single-energy and spread-out Bragg peak (SOBP) proton beam qualities at the Northwestern Medicine Chicago Proton Center. Increasing proton LET environments were acquired by placing film at increasing depths of Gammex HE Solid Water® whose water-equivalent thickness was characterized prior to measurement. RESULTS A strong LET dependence was observed near the Bragg peak (BP) consistent with previous studies performed with earlier versions of EBT3 film. The influence of range straggling on the film's LET response appears to have a uniform effect toward the BP regardless of the nominal beam energy. Proximal to this depth, the film's response decreased with decreasing energy at the same dose-average LET. The opposite trend was observed for depths past the BP. Changes in the SOBP energy modulation showed a linear relationship between the film's relative response and dose-averaged LET. Relative effectiveness factors (RE) were observed to range between 2%-7% depending on the width of the SOBP and depth of the film. Using the field-specific calibration technique, a total k = 1 uncertainty in the absorbed dose to water was estimated to range from 4.68%-5.21%. CONCLUSION While EBT3 film's strong LET dependence is a common problem in proton beam dosimetry, this work has shown that the LET dependence can be taken into account by carefully considering the depth and energy modulation across the film using field-specific corrections. RE factors were determined with a combined k = 1 uncertainty of 3.57% for SOBP environments and between 3.17%-4.69% for uniform, monoenergetic fields proximal to the distal 80% of the BP.
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Affiliation(s)
- Blake R Smith
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Mark Pankuch
- Division of Medical Physics, Northwestern Medicine Chicago Proton Center, 4455 Weaver Parkway, Warrenville, IL, 60555, USA
| | - Clifford G Hammer
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Larry A DeWerd
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Wesley S Culberson
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
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Parodi K, Polf JC. In vivo range verification in particle therapy. Med Phys 2018; 45:e1036-e1050. [PMID: 30421803 DOI: 10.1002/mp.12960] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/11/2018] [Accepted: 05/01/2018] [Indexed: 12/19/2022] Open
Abstract
Exploitation of the full potential offered by ion beams in clinical practice is still hampered by several sources of treatment uncertainties, particularly related to the limitations of our ability to locate the position of the Bragg peak in the tumor. To this end, several efforts are ongoing to improve the characterization of patient position, anatomy, and tissue stopping power properties prior to treatment as well as to enable in vivo verification of the actual dose delivery, or at least beam range, during or shortly after treatment. This contribution critically reviews methods under development or clinical testing for verification of ion therapy, based on pretreatment range and tissue probing as well as the detection of secondary emissions or physiological changes during and after treatment, trying to disentangle approaches of general applicability from those more specific to certain anatomical locations. Moreover, it discusses future directions, which could benefit from an integration of multiple modalities or address novel exploitation of the measurable signals for biologically adapted therapy.
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Affiliation(s)
- Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. Munich, 85748, Germany
| | - Jerimy C Polf
- Deparment of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, 22 South Greene St., Baltimore, MD, 21201, USA
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Moteabbed M, Trofimov A, Khan FH, Wang Y, Sharp GC, Zietman AL, Efstathiou JA, Lu HM. Impact of interfractional motion on hypofractionated pencil beam scanning proton therapy and VMAT delivery for prostate cancer. Med Phys 2018; 45:4011-4019. [PMID: 30007067 DOI: 10.1002/mp.13091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/07/2018] [Accepted: 06/01/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Hypofractionated radiotherapy of prostate cancer is gaining clinical acceptance given its potential increase in therapeutic ratio and evidence for noninferiority and lack of added late toxicities compared to conventional fractionation. However, concerns have been raised that smaller number of fractions might lead to larger dosimetric influence by interfractional motion. We aim to compare the effect of these variations on hypofractionated pencil beam scanning (PBS) proton therapy and volumetric modulated arc therapy (VMAT) for localized prostate cancer. METHODS Weekly CT images were acquired for 6 patients participating in a randomized clinical trial. PBS plans featuring bilateral (BL) and a combination of lateral and anterior-oblique beams (AOL), and VMAT plans were created. All patients were treated to a conventional 79.2 Gy total dose in 44 fractions. For this study, hypofractionated dose to the prostate gland was 51.6 Gy in 12 fractions or 36.25 Gy in 5 fractions, and 32.8, and 23.1 Gy to proximal seminal vesicles, respectively. Patients were simulated with endorectal balloons to aid gland immobilization. Three fiducial markers were implanted for setup guidance. All plans were recomputed on the weekly CT images after aligning with the simulation CT. The entire set of 9 CT images was used for dose recalculation for 12-fraction and only 5 used for the 5-fraction case. Adaptive range adjustments were applied to anterior-oblique beams assuming clinical availability of in vivo range verification. Fractional doses were summed using deformable dose accumulation to approximate the delivered dose. Biologically equivalent dose to 2 Gy(EQD2) was calculated assuming α/β of 1.5 Gy for prostate and 3 Gy for bladder and rectum. RESULTS The median delivered prostate D98 was 0.13/0.14/0.13 Gy(EQD2) smaller than planned for PBS-BL, 0.13/0.27/0.17 Gy(EQD2) for PBS-AOL and 0.59/0.66/0.59 Gy(EQD2) for VMAT, for 44/12/5 fractions, respectively. The largest D98 reduction was 1.5 and 3.5 Gy(EQD2) for CTV1 and CTV2, respectively. Target dose degradation was comparable for all fractionation schemes within each modality. The maximum increase in rectum D2 was 0.98 Gy(EQD2) for a 5-fraction PBS case. CONCLUSIONS The robustness of PBS and VMAT were comparable for all patients for the studied fractionations. The delivered target dose generally remained within clinical tolerance and the deviations were relatively minor for both fractionation schemes. The delivered OAR dose stayed in compliance with the RTOG hypofractionation constraints for all cases.
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Affiliation(s)
- Maryam Moteabbed
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexei Trofimov
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Fazal H Khan
- Department of Radiation Oncology, Miami Cancer Institute, Miami, FL, USA
| | - Yi Wang
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Gregory C Sharp
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Anthony L Zietman
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jason A Efstathiou
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Hsiao-Ming Lu
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Patch SK, Hoff DE, Webb TB, Sobotka LG, Zhao T. Two-stage ionoacoustic range verification leveraging Monte Carlo and acoustic simulations to stably account for tissue inhomogeneity and accelerator-specific time structure - A simulation study. Med Phys 2017; 45:783-793. [DOI: 10.1002/mp.12681] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 10/06/2017] [Accepted: 10/31/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Sarah K. Patch
- Department of Physics; University of Wisconsin-Milwaukee; Milwaukee WI USA
| | - Daniel E.M. Hoff
- Departments of Chemistry and Physics; Washington University; St. Louis MO USA
| | - Tyler B. Webb
- Departments of Chemistry and Physics; Washington University; St. Louis MO USA
| | - Lee G. Sobotka
- Departments of Chemistry and Physics; Washington University; St. Louis MO USA
| | - Tianyu Zhao
- Department of Radiation Oncology; Washington University; St. Louis MO USA
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Toltz A, Hoesl M, Schuemann J, Seuntjens J, Lu HM, Paganetti H. Time-resolved diode dosimetry calibration through Monte Carlo modeling for in vivo passive scattered proton therapy range verification. J Appl Clin Med Phys 2017; 18:200-205. [PMID: 29082601 PMCID: PMC5689909 DOI: 10.1002/acm2.12210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/01/2017] [Accepted: 09/28/2017] [Indexed: 11/15/2022] Open
Abstract
Purpose Our group previously introduced an in vivo proton range verification methodology in which a silicon diode array system is used to correlate the dose rate profile per range modulation wheel cycle of the detector signal to the water‐equivalent path length (WEPL) for passively scattered proton beam delivery. The implementation of this system requires a set of calibration data to establish a beam‐specific response to WEPL fit for the selected ‘scout’ beam (a 1 cm overshoot of the predicted detector depth with a dose of 4 cGy) in water‐equivalent plastic. This necessitates a separate set of measurements for every ‘scout’ beam that may be appropriate to the clinical case. The current study demonstrates the use of Monte Carlo simulations for calibration of the time‐resolved diode dosimetry technique. Methods Measurements for three ‘scout’ beams were compared against simulated detector response with Monte Carlo methods using the Tool for Particle Simulation (TOPAS). The ‘scout’ beams were then applied in the simulation environment to simulated water‐equivalent plastic, a CT of water‐equivalent plastic, and a patient CT data set to assess uncertainty. Results Simulated detector response in water‐equivalent plastic was validated against measurements for ‘scout’ spread out Bragg peaks of range 10 cm, 15 cm, and 21 cm (168 MeV, 177 MeV, and 210 MeV) to within 3.4 mm for all beams, and to within 1 mm in the region where the detector is expected to lie. Conclusion Feasibility has been shown for performing the calibration of the detector response for three ‘scout’ beams through simulation for the time‐resolved diode dosimetry technique in passive scattered proton delivery.
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Affiliation(s)
- Allison Toltz
- Department of Physics, McGill University, MUHC Cedars Cancer Centre DS1.7137, Montreal, QC, Canada
| | - Michaela Hoesl
- Computational Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jan Schuemann
- Department of Radiation Oncology, Francis H Burr Proton Therapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jan Seuntjens
- Medical Physics Unit, McGill University, MUHC Cedars Cancer Centre DS1.7137, Montreal, QC, Canada
| | - Hsiao-Ming Lu
- Department of Radiation Oncology, Francis H Burr Proton Therapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Harald Paganetti
- Department of Radiation Oncology, Francis H Burr Proton Therapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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15
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Xie Y, Bentefour EH, Janssens G, Smeets J, Vander Stappen F, Hotoiu L, Yin L, Dolney D, Avery S, O'Grady F, Prieels D, McDonough J, Solberg TD, Lustig RA, Lin A, Teo BKK. Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy. Int J Radiat Oncol Biol Phys 2017; 99:210-218. [PMID: 28816148 DOI: 10.1016/j.ijrobp.2017.04.027] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 03/22/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode. METHODS AND MATERIALS A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan. RESULTS In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field. CONCLUSIONS This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties.
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Affiliation(s)
- Yunhe Xie
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Guillaume Janssens
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | - Julien Smeets
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | | | - Lucian Hotoiu
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | - Lingshu Yin
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Derek Dolney
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephen Avery
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Fionnbarr O'Grady
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Damien Prieels
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | - James McDonough
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Timothy D Solberg
- Department of Radiation Oncology, University of California, San Francisco, California
| | - Robert A Lustig
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alexander Lin
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Boon-Keng K Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania.
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16
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Underwood TSA, Voog JC, Moteabbed M, Tang S, Soffen E, Cahlon O, Lu HM, Zietman AL, Efstathiou JA, Paganetti H. Hydrogel rectum-prostate spacers mitigate the uncertainties in proton relative biological effectiveness associated with anterior-oblique beams. Acta Oncol 2017; 56:575-581. [PMID: 28075206 DOI: 10.1080/0284186x.2016.1275781] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Anterior-oblique (AO) proton beams can form an attractive option for prostate patients receiving external beam radiotherapy (EBRT) as they avoid the femoral heads. For a cohort with hydrogel prostate-rectum spacers, we asked whether it was possible to generate AO proton plans robust to end-of-range elevations in linear energy transfer (LET) and modeled relative biological effectiveness (RBE). Additionally we considered how rectal spacers influenced planned dose distributions for AO and standard bilateral (SB) proton beams versus intensity-modulated radiotherapy (IMRT). MATERIAL AND METHODS We studied three treatment strategies for 10 patients with rectal spacers: (A) AO proton beams, (B) SB proton beams and (C) IMRT. For strategy (A) dose and LET distributions were simulated (using the TOPAS Monte Carlo platform) and the McNamara model was used to calculate proton RBE as a function of LET, dose per fraction, and photon α/β. All calculations were performed on pretreatment scans: inter- and intra-fractional changes in anatomy/set-up were not considered. RESULTS For 9/10 patients, rectal spacers enabled generation of AO proton plans robust to modeled RBE elevations: rectal dose constraints were fulfilled even when the variable RBE model was applied with a conservative α/β = 2 Gy. Amongst a subset of patients the proton rectal doses for the planning target volume plans were remarkably low: for 2/10 SB plans and 4/10 AO plans, ≤10% of the rectum received ≥20 Gy. AO proton plans delivered integral doses a factor of approximately three lower than IMRT and spared the femoral heads almost entirely. CONCLUSION Typically, rectal spacers enabled the generation of anterior beam proton plans that appeared robust to modeled variation in RBE. However, further analysis of day-to-day robustness would be required prior to a clinical implementation of AO proton beams. Such beams offer almost complete femoral head sparing, but their broader value relative to IMRT and SB protons remains unclear.
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Affiliation(s)
- Tracy S. A. Underwood
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Medical Physics and Bioengineering, University College London, London, UK
| | - Justin C. Voog
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Maryam Moteabbed
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Shikui Tang
- ProCure Proton Therapy Center, Somerset, NJ, USA
| | | | - Oren Cahlon
- ProCure Proton Therapy Center, Somerset, NJ, USA
| | - Hsiao-Ming Lu
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Anthony L. Zietman
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jason A. Efstathiou
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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17
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Jee KW, Zhang R, Bentefour EH, Doolan PJ, Cascio E, Sharp G, Flanz J, Lu HM. Investigation of time-resolved proton radiography using x-ray flat-panel imaging system. Phys Med Biol 2017; 62:1905-1919. [DOI: 10.1088/1361-6560/aa5a43] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Moteabbed M, Trofimov A, Sharp GC, Wang Y, Zietman AL, Efstathiou JA, Lu HM. Proton therapy of prostate cancer by anterior-oblique beams: implications of setup and anatomy variations. Phys Med Biol 2017; 62:1644-1660. [DOI: 10.1088/1361-6560/62/5/1644] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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19
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Bentefour EH, Schnuerer R, Lu HM. Concept of proton radiography using energy resolved dose measurement. Phys Med Biol 2016; 61:N386-93. [DOI: 10.1088/0031-9155/61/16/n386] [Citation(s) in RCA: 13] [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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