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Lin Y, Li W, Wang A, Johnson D, Gan GN, Gao H. Comprehensive dosimetric commissioning of proton minibeam radiotherapy on a single gantry proton system. Front Oncol 2024; 14:1421869. [PMID: 39099699 PMCID: PMC11294745 DOI: 10.3389/fonc.2024.1421869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 07/01/2024] [Indexed: 08/06/2024] Open
Abstract
Background Proton minibeam radiation therapy (pMBRT) can deliver spatially fractionated dose distributions with submillimeter resolution. These dose distributions exhibit significant heterogeneity in both depth and lateral directions. Accurate characterization of pMBRT doses requires dosimetry devices with high spatial resolution and a wide dynamic range. Furthermore, the dependency of dosimetric measurements on Linear Energy Transfer (LET), as observed in conventional proton therapy, is also present in pMBRT depth dose measurements. Purpose This work demonstrates the process of performing comprehensive dosimetric measurements to characterize the pMBRT collimator on a clinical single-gantry proton machine, utilizing commercially available dosimetry devices. Methods The minibeam collimator is designed to be mounted on the clinical nozzle as a beam-modifying accessory. Three collimators, each with a slit opening of 0.4 mm, are thoroughly evaluated. The center-to-center (c-t-c) distances of the slits for these collimators are 2.8 mm, 3.2 mm, and 4.0 mm, respectively. High spatial resolution dosimetry devices are essential for PMBRT dose characterizations. To meet this requirement, two-dimensional (2D) dose measurement devices, Gafchromic films, are used to measure lateral profiles at various depths. Films are also used for depth dose profile measurements in solid water. Additionally, high-resolution point dose detectors, microDiamond, and Razor diode detectors are employed for lateral profile measurements at various depths. Percent depth dose (PDD) measurements of pMBRT in solid water, with various proton energies, collimators, and air gaps, are performed using Gafchromic films. The film's LET dependency for proton beams is corrected to ensure accurate pMBRT PDD measurements. The Monte Carlo simulation tool TOPAS is utilized to compare and validate all experimental measurements. Results At depths where LET is not a concern, film dose measurements were consistent with microDiamond and Razor diode point measurements. The point detectors need to be orientated with the thin side aligned to the incoming beam. Comparison of the lateral dose profiles extracted from TOPAS simulations, films, microDiamond, and Razor diode detectors shows a passing rate exceeding 98% in 1D gamma analysis at 3% 0.1 mm criteria.However, when the microDiamond detector is orientated to face the pMBRT beam, its spatial resolution may not be sufficient to capture the peak and valley dose accurately. Nevertheless, an accuracy within 2% can still be achieved when comparing the average dose. The PDD measurements show that the peak valley dose ratio (PVDR) of pMBRT can be altered at different depths with different air gaps using the same collimator or different collimators of different c-t-c distances. Conclusion Our study demonstrates that comprehensive dose measurements for pMBRT can be conducted using standard clinical dose measurement devices. These measurements are indispensable for guiding and ensuring accurate dose reporting in pre-clinical studies using the pMBRT technique.
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Affiliation(s)
- Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Wangyao Li
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Aoxiang Wang
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Daniel Johnson
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Gregory N. Gan
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
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Domingo Muñoz I, Van Hoey O, Parisi A, Bassler N, Grzanka L, De Saint-Hubert M, Vaniqui A, Olko P, Sądel M, Stolarczyk L, Vestergaard A, Jäkel O, Gardenali Yukihara E, Brage Christensen J. Assessment of fluence- and dose-averaged linear energy transfer with passive luminescence detectors in clinical proton beams. Phys Med Biol 2024; 69:135004. [PMID: 38774985 DOI: 10.1088/1361-6560/ad4e8e] [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: 12/15/2023] [Accepted: 05/21/2024] [Indexed: 06/22/2024]
Abstract
Objective.This work investigates the use of passive luminescence detectors to determine different types of averaged linear energy transfer (LET-) for the energies relevant to proton therapy. The experimental results are compared to reference values obtained from Monte Carlo simulations.Approach.Optically stimulated luminescence detectors (OSLDs), fluorescent nuclear track detectors (FNTDs), and two different groups of thermoluminescence detectors (TLDs) were irradiated at four different radiation qualities. For each irradiation, the fluence- (LET-f) and dose-averaged LET (LET-d) were determined. For both quantities, two sub-types of averages were calculated, either considering the contributions from primary and secondary protons or from all protons and heavier, charged particles. Both simulated and experimental data were used in combination with a phenomenological model to estimate the relative biological effectiveness (RBE).Main results.All types ofLET-could be assessed with the luminescence detectors. The experimental determination ofLET-fis in agreement with reference data obtained from simulations across all measurement techniques and types of averaging. On the other hand,LET-dcan present challenges as a radiation quality metric to describe the detector response in mixed particle fields. However, excluding secondaries heavier than protons from theLET-dcalculation, as their contribution to the luminescence is suppressed by ionization quenching, leads to equal accuracy betweenLET-fandLET-d. Assessment of RBE through the experimentally determinedLET-dvalues agrees with independently acquired reference values, indicating that the investigated detectors can determineLET-with sufficient accuracy for proton therapy.Significance.OSLDs, TLDs, and FNTDs can be used to determineLET-and RBE in proton therapy. With the capability to determine dose through ionization quenching corrections derived fromLET-, OSLDs and TLDs can simultaneously ascertain dose,LET-, and RBE. This makes passive detectors appealing for measurements in phantoms to facilitate validation of clinical treatment plans or experiments related to proton therapy.
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Affiliation(s)
- Iván Domingo Muñoz
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | | | - Alessio Parisi
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, United States of America
| | - Niels Bassler
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Leszek Grzanka
- Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), Kraków, Poland
| | | | - Ana Vaniqui
- Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Paweł Olko
- Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), Kraków, Poland
| | - Michał Sądel
- Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), Kraków, Poland
| | - Liliana Stolarczyk
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Anne Vestergaard
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Oliver Jäkel
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg University Hospital, Heidelberg, Germany
| | | | - Jeppe Brage Christensen
- Department of Radiation Safety and Security, Paul Scherrer Institute (PSI), Villigen PSI, Switzerland
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3
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Wong YM, Koh CWY, Lew KS, Chua CGA, Yeap PL, Andrew W, Zubin M, Poh SS, Lew WS, Lee JCL, Park SY, Tan HQ. Effects of modern aesthetic dental fillings on proton therapy. Phys Imaging Radiat Oncol 2024; 29:100552. [PMID: 38405428 PMCID: PMC10891317 DOI: 10.1016/j.phro.2024.100552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/30/2024] [Accepted: 02/08/2024] [Indexed: 02/27/2024] Open
Abstract
Background and purpose High-density dental fillings pose a non-negligible impact on head and neck cancer treatment. For proton therapy, stopping power ratio (SPR) prediction will be significantly impaired by the associated image artifacts. Dose perturbation is also inevitable, compromising the treatment plan quality. While plenty of work has been done on metal or amalgam fillings, none has touched on composite resin (CR) and glass ionomer cement (GIC) which have seen an increasing usage. Hence, this work aims to provide a detailed characterisation of SPR and dose perturbation in proton therapy caused by CR and GIC. Materials and methods Four types of fillings were used: CR, Fuji Bulk (FB), Fuji II (FII) and Fuji IX (FIX). The latter three belong to GIC category. Measured SPR were compared with SPR predicted using single-energy computed tomography (SECT) and dual-energy computed tomography (DECT). Dose perturbation of proton beams with lower- and higher-energy levels was also quantified using Gafchromic films. Results The measured SPR for CR, FB, FII and FIX were 1.68, 1.77, 1.77 and 1.76, respectively. Overall, DECT could predict SPR better than SECT. The lowest percentage error achieved by DECT was 19.7 %, demonstrating the challenge in estimating SPR, even for fillings with relatively lower densities. For both proton beam energies and all four fillings of about 4.5 mm thickness, the maximum dose perturbation was 3 %. Conclusion This study showed that dose perturbation by CR and GIC was comparatively small. We have measured and recommended the SPR values for overriding the fillings in TPS.
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Affiliation(s)
- Yun Ming Wong
- Division of Physics and Applied Physics, Nanyang Technological University, Singapore
| | | | - Kah Seng Lew
- Division of Physics and Applied Physics, Nanyang Technological University, Singapore
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | | | - Ping Lin Yeap
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
- Department of Oncology, University of Cambridge, United Kingdom
| | - Wibawa Andrew
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Master Zubin
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Sharon Shuxian Poh
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Wen Siang Lew
- Division of Physics and Applied Physics, Nanyang Technological University, Singapore
| | - James Cheow Lei Lee
- Division of Physics and Applied Physics, Nanyang Technological University, Singapore
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Sung Yong Park
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
- Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore
| | - Hong Qi Tan
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
- Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore
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Maeyama T, Mochizuki A, Yoshida K, Fukunishi N, Ishikawa KL, Fukuda S. Radio-fluorogenic nanoclay gel dosimeters with reduced linear energy transfer dependence for carbon-ion beam radiotherapy. Med Phys 2023; 50:1073-1085. [PMID: 36335533 DOI: 10.1002/mp.16092] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 10/07/2022] [Accepted: 10/25/2022] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The precise assessment of the dose distribution of high linear energy transfer (LET) radiation remains a challenge, because the signal of most dosimeters will be saturated due to the high ionization density. Such measurements are particularly important for heavy-ion beam cancer therapy. On this basis, the present work examined the high LET effect associated with three-dimensional gel dosimetry based on radiation-induced chemical reactions. The purpose of this study was to create an ion beam radio-fluorogenic gel dosimeter with a reduced effect of LET. METHODS Nanoclay radio-fluorogenic gel (NC-RFG) dosimeters were prepared, typically containing 100 μM dihydrorhodamine 123 (DHR123) and 2.0 wt% nanoclay together with catalytic additives promoting Fenton or Fenton-like reactions. The radiological properties of NC-RFG dosimeters having different compositions in response to a carbon-ion beam were investigated using a fluorescence gel scanner. RESULTS An NC-RFG dosimeter capable of generating a fluorescence intensity distribution reflecting the carbon-ion beam dose profile was obtained. It was clarified that the reduction of the unfavorable LET dependence results from an acceleration of the reactions between DHR123 and H2 O2 , which is a molecular radiolysis product. The effects of varying the preparation conditions on the radiological properties of these gels were also examined. The optimum H2 O2 catalyst was determined to include 1 mM Fe3+ ions, and the addition of 100 mM pyridine was also found to increase the sensitivity. CONCLUSIONS This technique allows the first-ever evaluation of the depth-dose profile of a carbon-ion beam at typical therapeutic levels of several Gy without LET effect.
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Affiliation(s)
- Takuya Maeyama
- Department of Chemistry, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan.,RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
| | - Anri Mochizuki
- Department of Chemistry, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Kazuki Yoshida
- Department of Chemistry, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Nobuhisa Fukunishi
- RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
| | - Kenichi L Ishikawa
- Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shigekazu Fukuda
- QST Hospital, National Institutes for Quantum Science and Technology, Inage-ku, Chiba, Japan
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Resch AF, Padilla Cabal F, Regodic M, Lechner W, Heilemann G, Kuess P, Georg D, Palmans H. Accelerating and improving radiochromic film calibration by utilizing the dose ratio in photon and proton beams. Med Phys 2022; 49:6150-6160. [PMID: 35754376 PMCID: PMC9543697 DOI: 10.1002/mp.15828] [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: 12/06/2021] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/12/2022] Open
Abstract
Purpose Radiochromic films are versatile 2D dosimeters with high‐resolution and near tissue equivalence. To assure high precision and accuracy, a time‐consuming calibration process is required. To improve the time efficiency, a novel calibration method utilizing the ratio of the same dose profile measured at different monitor units (MUs) is introduced and tested in a proton and photon beam. Methods The calibration procedure employs the dose ratio of film measurements of the same relative profile for different absolute dose values. Hence, the ratio of the dose is constant at any point of the profile, but the ratio of the net optical densities is not constant. The key idea of the method is to optimize the calibration function until the ratio of the calculated doses is constant. The proposed method was tested in the dose range between 0.25–12 and 1–6 Gy in a proton and photon beam, respectively. A radial symmetric profile and a rectangular profile were created, both having a central plateau region of about 3 cm diameter and a dose falloff of about 1.5 cm at larger distances. The dose falloff region was used as input for the optimization method and the central plateau region served as dose reference points. Only the plateau region of the highest dose entered the optimization as an additional objective. The measured data were randomly split into differently sized training and test sets. The optimization was repeated 1000 times with random start value initialization using the same start values for the standard and the gradient method. Finally, a proton plan with four dose levels was created, which were separated spatially, to test the possibility of a full calibration within a single measurement. Results Parameter estimation was possible with as low as one dose ratio used for optimization in both the photon and the proton case, yet exhibiting a high sensitivity on the dose level. The root mean squared deviation (RMSD) of the dose was less than 1% when the dose ratio was in the order of 20, whereas the median RMSD of all optimizations was 1.7%. Using four dose levels for optimization resulted in a median RMSD of 1% when randomly selecting the dose levels. Having at least one dose ratio of about 20 included in the optimization considerably improved the RMSD of the calibration function. Using six or eight dose levels reduced the sensitivity on the dose level selection and the median RMSD was 0.8%. A full calibration was possible in a single measurement having four dose levels in one plan but spatially separated. Conclusions The number of measurements required to obtain an EBT3 film calibration function could be reduced using the proposed dose ratio method while maintaining the same accuracy as with the standard method.
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Affiliation(s)
- Andreas F. Resch
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Fatima Padilla Cabal
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Milovan Regodic
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Wolfgang Lechner
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Gerd Heilemann
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Peter Kuess
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Dietmar Georg
- Division Medical Radiation PhysicsDepartment of Radiation OncologyMedical University of Vienna/AKH WienViennaAustria
| | - Hugo Palmans
- MedAustron Ion Therapy CentreWiener NeustadtAustria
- Medical Radiation ScienceNational Physical LaboratoryTeddingtonUnited Kingdom
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6
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Christensen JB, Togno M, Bossin L, Pakari OV, Safai S, Yukihara EG. Improved simultaneous LET and dose measurements in proton therapy. Sci Rep 2022; 12:8262. [PMID: 35585205 PMCID: PMC9117334 DOI: 10.1038/s41598-022-10575-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 04/11/2022] [Indexed: 11/23/2022] Open
Abstract
The objective of this study was to improve the precision of linear energy transfer (LET) measurements using \documentclass[12pt]{minimal}
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\begin{document}$$\text {Al}_2\text {O}_3\text {:C}$$\end{document}Al2O3:C optically stimulated luminescence detectors (OSLDs) in proton beams, and, with that, improve OSL dosimetry by correcting the readout for the LET-dependent ionization quenching. The OSLDs were irradiated in spot-scanning proton beams at different doses for fluence-averaged LET values in the (0.4–6.5) \documentclass[12pt]{minimal}
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\begin{document}$$\hbox {keV}\, \upmu \hbox {m}^{-1}$$\end{document}keVμm-1 range (in water). A commercial automated OSL reader with a built-in beta source was used for the readouts, which enabled a reference irradiation and readout of each OSLD to establish individual corrections. Pulsed OSL was used to separately measure the blue (F-center) and UV (\documentclass[12pt]{minimal}
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\begin{document}$$F^+$$\end{document}F+-center) emission bands of \documentclass[12pt]{minimal}
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\begin{document}$$\text {Al}_2\text {O}_3\text {:C}$$\end{document}Al2O3:C and the ratio between them (UV/blue signal) was used for the LET measurements. The average deviation between the simulated and measured LET values along the central beam axis amounts to 5.5% if both the dose and LET are varied, but the average deviation is reduced to 3.5% if the OSLDs are irradiated with the same doses. With the measurement procedure and automated equipment used here, the variation in the signals used for LET estimates and quenching-corrections is reduced from 0.9 to 0.6%. The quenching-corrected OSLD doses are in agreement with ionization chamber measurements within the uncertainties. The automated OSLD corrections are demonstrated to improve the LET estimates and the ionization quenching-corrections in proton dosimetry for a clinically relevant energy range up to 230 MeV. It is also for the first time demonstrated how the LET can be estimated for different doses.
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Affiliation(s)
- Jeppe Brage Christensen
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland.
| | - Michele Togno
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Lily Bossin
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Oskari Ville Pakari
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Sairos Safai
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
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Hahn C, Ödén J, Dasu A, Vestergaard A, Fuglsang Jensen M, Sokol O, Pardi C, Bourhaleb F, Leite A, de Marzi L, Smith E, Aitkenhead A, Rose C, Merchant M, Kirkby K, Grzanka L, Pawelke J, Lühr A. Towards harmonizing clinical linear energy transfer (LET) reporting in proton radiotherapy: a European multi-centric study. Acta Oncol 2022; 61:206-214. [PMID: 34686122 DOI: 10.1080/0284186x.2021.1992007] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Clinical data suggest that the relative biological effectiveness (RBE) in proton therapy (PT) varies with linear energy transfer (LET). However, LET calculations are neither standardized nor available in clinical routine. Here, the status of LET calculations among European PT institutions and their comparability are assessed. MATERIALS AND METHODS Eight European PT institutions used suitable treatment planning systems with their center-specific beam model to create treatment plans in a water phantom covering different field arrangements and fulfilling commonly agreed dose objectives. They employed their locally established LET simulation environments and procedures to determine the corresponding LET distributions. Dose distributions D1.1 and DRBE assuming constant and variable RBE, respectively, and LET were compared among the institutions. Inter-center variability was assessed based on dose- and LET-volume-histogram parameters. RESULTS Treatment plans from six institutions fulfilled all clinical goals and were eligible for common analysis. D1.1 distributions in the target volume were comparable among PT institutions. However, corresponding LET values varied substantially between institutions for all field arrangements, primarily due to differences in LET averaging technique and considered secondary particle spectra. Consequently, DRBE using non-harmonized LET calculations increased inter-center dose variations substantially compared to D1.1 and significantly in mean dose to the target volume of perpendicular and opposing field arrangements (p < 0.05). Harmonizing LET reporting (dose-averaging, all protons, LET to water or to unit density tissue) reduced the inter-center variability in LET to the order of 10-15% within and outside the target volume for all beam arrangements. Consequentially, inter-institutional variability in DRBE decreased to that observed for D1.1. CONCLUSION Harmonizing the reported LET among PT centers is feasible and allows for consistent multi-centric analysis and reporting of tumor control and toxicity in view of a variable RBE. It may serve as basis for harmonized variable RBE dose prescription in PT.
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Affiliation(s)
- Christian Hahn
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Medical Physics and Radiotherapy, Department of Physics, TU Dortmund University, Dortmund, Germany
| | - Jakob Ödén
- RaySearch Laboratories AB, Stockholm, Sweden
| | - Alexandru Dasu
- The Skandion Clinic, Uppsala, Sweden
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Anne Vestergaard
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | | | - Olga Sokol
- GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany
| | - Claudia Pardi
- I-SEE (Internet-Simulation Evaluation Envision), Torino, Italy
| | - Faiza Bourhaleb
- I-SEE (Internet-Simulation Evaluation Envision), Torino, Italy
| | - Amélia Leite
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, Orsay, France
| | - Ludovic de Marzi
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, Orsay, France
- Institut Curie, PSL Research University, University Paris Saclay, Inserm LITO, Orsay, France
| | - Edward Smith
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, UK
| | - Adam Aitkenhead
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, UK
| | - Christopher Rose
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, UK
| | - Michael Merchant
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, UK
| | - Karen Kirkby
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, UK
| | - Leszek Grzanka
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
| | - Jörg Pawelke
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
| | - Armin Lühr
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Medical Physics and Radiotherapy, Department of Physics, TU Dortmund University, Dortmund, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
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8
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Ruangchan S, Palmans H, Knäusl B, Georg D, Clausen M. Dose calculation accuracy in particle therapy: Comparing carbon ions with protons. Med Phys 2021; 48:7333-7345. [PMID: 34482555 PMCID: PMC9291072 DOI: 10.1002/mp.15209] [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: 03/29/2021] [Revised: 06/02/2021] [Accepted: 08/18/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE This work presents the validation of an analytical pencil beam dose calculation algorithm in a commercial treatment planning system (TPS) for carbon ions by measurements of dose distributions in heterogeneous phantom geometries. Additionally, a comparison study of carbon ions versus protons is performed considering current best solutions in commercial TPS. METHODS All treatment plans were optimized and calculated using the RayStation TPS (RaySearch, Sweden). The dose distributions calculated with the TPS were compared with measurements using a 24-pinpoint ionization chamber array (T31015, PTW, Germany). Tissue-like inhomogeneities (bone, lung, and soft tissue) were embedded in water, while a target volume of 4 x 4 x 4 cm3 was defined at two different depths behind the heterogeneities. In total, 10 different test cases, with and without range shifter as well as different air gaps, were investigated. Dose distributions inside as well as behind the target volume were evaluated. RESULTS Inside the target volume, the mean dose difference between calculations and measurements, averaged over all test cases, was 1.6% for carbon ions. This compares well to the final agreement of 1.5% obtained in water at the commissioning stage of the TPS for carbon ions and is also within the clinically acceptable interval of 3%. The mean dose difference and maximal dose difference obtained outside the target area were 1.8% and 13.4%, respectively. The agreement of dose distributions for carbon ions in the target volumes was comparable or better to that between Monte Carlo (MC) dose calculations and measurements for protons. Percentage dose differences of more than 10% were present outside the target area behind bone-lung structures, where the carbon ion calculations systematically over predicted the dose. MC dose calculations for protons were superior to carbon ion beams outside the target volumes. CONCLUSION The pencil beam dose calculations for carbon ions in RayStation were found to be in good agreement with dosimetric measurements in heterogeneous geometries for points of interest located within the target. Large local discrepancies behind the target may contribute to incorrect dose predictions for organs at risk.
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Affiliation(s)
- Sirinya Ruangchan
- Department of Radiation OncologyMedical University of ViennaViennaAustria
- Department of RadiologyKing Chulalongkorn Memorial HospitalBangkokThailand
| | - Hugo Palmans
- Division of Medical PhysicsMedAustron Ion Therapy CenterWiener NeustadtAustria
- Medical Radiation ScienceNational Physical LaboratoryTeddingtonUK
| | - Barbara Knäusl
- Department of Radiation OncologyMedical University of ViennaViennaAustria
- Division of Medical PhysicsMedAustron Ion Therapy CenterWiener NeustadtAustria
| | - Dietmar Georg
- Department of Radiation OncologyMedical University of ViennaViennaAustria
- Division of Medical PhysicsMedAustron Ion Therapy CenterWiener NeustadtAustria
| | - Monika Clausen
- Department of Radiation OncologyMedical University of ViennaViennaAustria
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9
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Sanchez-Parcerisa D, Sanz-García I, Ibáñez P, España S, Espinosa A, Gutiérrez-Neira C, López A, Vera JA, Mazal A, Fraile LM, Udías JM. Radiochromic film dosimetry for protons up to 10 MeV with EBT2, EBT3 and unlaminated EBT3 films. Phys Med Biol 2021; 66. [PMID: 33910190 DOI: 10.1088/1361-6560/abfc8d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/28/2021] [Indexed: 11/12/2022]
Abstract
Passive dosimetry with radiochromic films is widely used in proton radiotherapy, both in clinical and scientific environments, thanks to its simplicity, high spatial resolution and dose-rate independence. However, film under-response for low-energy protons, the so-called linear-energy transfer (LET) quenching, must be accounted and corrected for. We perform a meta-analysis on existing film under-response data with EBT, EBT2 and EBT3 GAFchromic™ films and provide a common framework to integrate it, based on the calculation of dose-averaged LET in the active layer of the films. We also report on direct measurements with the 10 MeV proton beam at the Center for Microanalysis of Materials (CMAM) for EBT2, EBT3 and unlaminated EBT3 films, focusing on the 20-80 keVμm-1LET range, where previous data was scarce. Measured film relative efficiency (RE) values are in agreement with previously reported data from the literature. A model on film RE constructed with combined literature and own experimental values in the 5-80 keVμm-1LET range is presented, supporting the hypothesis of a linear decrease of RE with LET, with no remarkable differences between the three types of films analyzed.
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Affiliation(s)
- Daniel Sanchez-Parcerisa
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.,Sedecal Molecular Imaging, Algete, Madrid, Spain
| | - Irene Sanz-García
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - Paula Ibáñez
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Samuel España
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.,Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Andrea Espinosa
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Carolina Gutiérrez-Neira
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Centro de Microanálisis de Materiales (CMAM), Universidad Autónoma de Madrid, Spain.,ALBA Synchrotron Light Source (CELLS-ALBA), Cerdanyola del Vallès, Barcelona, Spain
| | - Alfonso López
- Dept. de Radiofísica y Protección Radiológica, Hospital de Fuenlabrada, Madrid, Spain
| | - Juan Antonio Vera
- Centro de Protonterapia de Quirónsalud, Pozuelo de Alarcón, Madrid, Spain
| | - Alejandro Mazal
- Centro de Protonterapia de Quirónsalud, Pozuelo de Alarcón, Madrid, Spain
| | - Luis Mario Fraile
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - José Manuel Udías
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
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10
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Valdetaro LB, Høye EM, Skyt PS, Petersen JBB, Balling P, Muren LP. Empirical quenching correction in radiochromic silicone-based three-dimensional dosimetry of spot-scanning proton therapy. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 18:11-18. [PMID: 34258402 PMCID: PMC8254200 DOI: 10.1016/j.phro.2021.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 11/24/2022]
Abstract
Background and purpose Three-dimensional dosimetry of proton therapy (PT) with chemical dosimeters is challenged by signal quenching, which is a lower dose-response in regions with high ionization density due to high linear-energy-transfer (LET) and dose-rate. This study aimed to assess the viability of an empirical correction model for 3D radiochromic silicone-based dosimeters irradiated with spot-scanning PT, by parametrizing its LET and dose-rate dependency. Materials and methods Ten cylindrical radiochromic dosimeters (Ø50 and Ø75 mm) were produced in-house, and irradiated with different spot-scanning proton beam configurations and machine-set dose rates ranging from 56 to 145 Gy/min. Beams with incident energies of 75, 95 and 120 MeV, a spread-out Bragg peak and a plan optimized to an irregular target volume were included. Five of the dosimeters, irradiated with 120 MeV beams, were used to estimate the quenching correction factors. Monte Carlo simulations were used to obtain dose and dose-averaged-LET (LETd) maps. Additionally, a local dose-rate map was estimated, using the simulated dose maps and the machine-set dose-rate information retrieved from the irradiation log-files. Finally, the correction factor was estimated as a function of LETd and local dose-rate and tested on the different fields. Results Gamma-pass-rates of the corrected measurements were >94% using a 3%-3 mm gamma analysis and >88% using 2%-2 mm, with a dose deviation of <5.6 ± 1.8%. Larger dosimeters showed a 20% systematic increase in dose-response, but the same quenching in signal when compared to the smaller dosimeters. Conclusion The quenching correction model was valid for different dosimeter sizes to obtain relative dosimetric maps of complex dose distributions in PT.
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Affiliation(s)
- Lia Barbosa Valdetaro
- Danish Centre for Particle Therapy, Aarhus University Hospital, 8200 Aarhus N, Denmark.,Department of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark
| | - Ellen Marie Høye
- Department of Oncology and Medical Physics, Haukeland University Hospital, 5021 Bergen, Norway
| | - Peter Sandegaard Skyt
- Danish Centre for Particle Therapy, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | | | - Peter Balling
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Ludvig Paul Muren
- Danish Centre for Particle Therapy, Aarhus University Hospital, 8200 Aarhus N, Denmark.,Department of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark.,Medical Physics, Department of Oncology, Aarhus University Hospital, 8200 Aarhus N, Denmark
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11
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Setianegara J, Mazur TR, Yang D, Li HH. Dual-storage phosphor proton therapy dosimetry: Simultaneous quantification of dose and linear energy transfer. Med Phys 2021; 48:1941-1955. [PMID: 33525050 DOI: 10.1002/mp.14748] [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: 10/09/2020] [Revised: 12/28/2020] [Accepted: 01/18/2021] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To investigate the feasibility of using the high Zeff storage phosphor material BaFBrI:Eu2+ in conjunction with the low Zeff storage phosphor material KCl:Eu2+ for simultaneous proton dose and linear energy transfer (LET) measurements by (a) measuring the fundamental optical and dosimetric properties of BaFBrI:Eu2+ , (b) evaluating its compatibility in being readout simultaneously with KCl:Eu2+ dosimeters, and (c) modeling and validating its LET dependence under elevated proton LET irradiation. METHODS A commercial BaFBrI:Eu2+ storage phosphor detector (Model ST-VI, Fujifilm) was characterized with energy dispersive x-ray spectroscopy (EDS) analysis to obtain its elemental composition. The dosimeters were irradiated using both a Mevion S250 proton therapy unit (at the center of a spread-out Bragg peak, SOBP) and a Varian Clinac iX linear accelerator with the latter being a low LET irradiation. The photostimulated luminescence (PSL) emission spectra, excitation spectra, and luminescent lifetimes of the detector were measured after proton and photon irradiations. Dosimetric properties including dose linearity, dose rate dependence, radiation hardness, temporal, and readout stabilities were studied using a laboratory optical reader after proton irradiations. In addition, its proton energy dependence was analytically modeled and experimentally validated by irradiating the detectors at various depths within the SOBP (Range: 15.0 g/cm2 , Modulation: 10.0 g/cm2 ). RESULTS The active detector composition for the high Zeff storage phosphor detector was found to be BaFBr0.85 I0.15 :Eu2+ . The BaFBr0.85 I0.15 :Eu2+ material's excitation and emission spectra were in agreement under proton and photon irradiations, with peaks of 586 ± 1 nm and 400 ± 1 nm, respectively, with a full width at half maximum (FWHM) of 119 ± 3 nm and 30 ± 2 nm, respectively. As dosimeter response under photon irradiation is generally believed to be free from LET effect, these results suggest LET independence of charge storage center types resulted from ionizing radiations. There is sufficient spectral overlaps with KCl:Eu2+ dosimeters allowing both dosimeters to be readout under equivalent readout conditions, that is, 594 nm stimulation and 420 nm detection wavelengths. Its PSL characteristic lifetime was found to be less than 5 microseconds which would make it suitable for fast 2D readout post irradiation. Its 420 nm emission band intensity was found to be linear up to 10 Gy absolute proton dose under the same irradiation conditions, dose rate independent, stable in time and under multiple readouts, and with high radiation hardness under cumulative proton dose histories up to 200 Gy as tested in this study. BaFBr0.85 I0.15 :Eu2+ showed significant proton energy-dependent dose under-response in regions of high LET which could be modeled by stopping power ratio calculations with an accuracy of 3% in low LET regions and a distance-to-agreement (DTA) of 1 mm in high LET regions (>5 keV/μm). CONCLUSION We have proven the feasibility of dual-storage phosphor proton dosimetry for simultaneous proton dose and LET measurements. BaFBr0.85 I0.15 :Eu2+ has shown equally excellent dosimetry performance as its low Zeff complement KCl:Eu2+ with distinctive LET dependence merely as a result of its higher Zeff . These promising results pave the way for future studies involving simultaneous proton dose and LET measurements using this novel approach.
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Affiliation(s)
- Jufri Setianegara
- Department of Radiation Oncology, Washington University in St. Louis, MO, 63110, USA.,Department of Physics, Washington University in St. Louis, MO, 63110, USA
| | - Thomas R Mazur
- Department of Radiation Oncology, Washington University in St. Louis, MO, 63110, USA
| | - Deshan Yang
- Department of Radiation Oncology, Washington University in St. Louis, MO, 63110, USA
| | - H Harold Li
- Department of Radiation Oncology, Washington University in St. Louis, MO, 63110, USA.,Department of Biomedical Engineering, Washington University in St. Louis, MO, 63110, USA
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12
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Moftah B, Aldelaijan S, Shehadeh M, Alzorkany F, Alrumayan F, Alsbeih G, Alshabanah M, Seuntjens J, Tomic N, Devic S. Calibration of MTT assay in proton beams using radiochromic films. Phys Med 2020; 77:146-153. [PMID: 32861190 DOI: 10.1016/j.ejmp.2020.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/31/2020] [Accepted: 08/04/2020] [Indexed: 10/23/2022] Open
Abstract
PURPOSE This study provides methodology of calibrating as well as controlling the output for an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay irradiated in a low energy proton beam using EBT3-model GAFCHROMICTM film, without correcting for quenching effect. METHODS A calibrated Markus ionization chamber was used to measure the depth dose and beam output for 26.5 MeV protons produced by a CS30 cyclotron. A time-controlled aluminum cylinder was added in front of the horizontal beam-exit serving as a radiation shutter. Following the TRS-398 reference dosimetry protocol for proton beams, the output was calibrated in water at a reference depth of 3 mm. EBT3 film was calibrated for doses up to 8 Gy at the same depth. To verify the dose distribution for each 96-well MTT assay plate, EBT3 film was placed at the reference depth during irradiation and cell doses were scaled by measured percent depth dose (PDD) data. RESULTS The radiochromic film dosimetry system in this study provides dose measurements with an uncertainty better than 3.3% for doses higher than 1 Gy. From a single exposure and utilizing the Gaussian shape of the beam, multiple dose points can be obtained within different wells of the same plate ranging from 6.9 Gy (sigma ∼4%) in the central well, and 2 Gy (sigma ∼8%) for wells positioned closer to the periphery. CONCLUSIONS We described a methodology for radiochromic film-based dose monitoring system, using low-energy protons, which can be used for the MTT assay in any proton beam, except within Bragg peak region.
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Affiliation(s)
- B Moftah
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia; Medical Physics Unit, McGill University, Montréal, Québec, Canada
| | - S Aldelaijan
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - M Shehadeh
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - F Alzorkany
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - F Alrumayan
- Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - G Alsbeih
- Radiation Biology Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - M Alshabanah
- Oncology Centre, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - J Seuntjens
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - N Tomic
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Radiation Oncology, Jewish General Hospital, Montréal, Québec, Canada
| | - S Devic
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Radiation Oncology, Jewish General Hospital, Montréal, Québec, Canada.
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