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Kugel F, Wulff J, Bäumer C, Janson M, Kretschmer J, Brodbek L, Behrends C, Verbeek N, Looe HK, Poppe B, Timmermann B. Validating a double Gaussian source model for small proton fields in a commercial Monte-Carlo dose calculation engine. Z Med Phys 2023; 33:529-541. [PMID: 36577626 PMCID: PMC10751706 DOI: 10.1016/j.zemedi.2022.11.011] [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: 02/19/2022] [Revised: 11/13/2022] [Accepted: 11/28/2022] [Indexed: 12/27/2022]
Abstract
PURPOSE The primary fluence of a proton pencil beam exiting the accelerator is enveloped by a region of secondaries, commonly called "spray". Although small in magnitude, this spray may affect dose distributions in pencil beam scanning mode e.g., in the calculation of the small field output, if not modelled properly in a treatment planning system (TPS). The purpose of this study was to dosimetrically benchmark the Monte Carlo (MC) dose engine of the RayStation TPS (v.10A) in small proton fields and systematically compare single Gaussian (SG) and double Gaussian (DG) modeling of initial proton fluence providing a more accurate representation of the nozzle spray. METHODS The initial proton fluence distribution for SG/DG beam modeling was deduced from two-dimensional measurements in air with a scintillation screen with electronic readout. The DG model was either based on direct fits of the two Gaussians to the measured profiles, or by an iterative optimization procedure, which uses the measured profiles to mimic in-air scan-field factor (SF) measurements. To validate the DG beam models SFs, i.e. relative doses to a 10 × 10 cm2 field, were measured in water for three different initial proton energies (100MeV, 160MeV, 226.7MeV) and square field sizes from 1×1cm2 to 10×10cm2 using a small field ionization chamber (IBA CC01) and an IBA ProteusPlus system (universal nozzle). Furthermore, the dose to the center of spherical target volumes (diameters: 1cm to 10cm) was determined using the same small volume ionization chamber (IC). A comprehensive uncertainty analysis was performed, including estimates of influence factors typical for small field dosimetry deduced from a simple two-dimensional analytical model of the relative fluence distribution. Measurements were compared to the predictions of the RayStation TPS. RESULTS SFs deviated by more than 2% from TPS predictions in all fields <4×4cm2 with a maximum deviation of 5.8% for SG modeling. In contrast, deviations were smaller than 2% for all field-sizes and proton energies when using the directly fitted DG model. The optimized DG model performed similarly except for slightly larger deviations in the 1×1cm2 scan-fields. The uncertainty estimates showed a significant impact of pencil beam size variations (±5%) resulting in up to 5.0% standard uncertainty. The point doses within spherical irradiation volumes deviated from calculations by up to 3.3% for the SG model and 2.0% for the DG model. CONCLUSION Properly representing nozzle spray in RayStation's MC-based dose engine using a DG beam model was found to reduce the deviation to measurements in small spherical targets to below 2%. A thorough uncertainty analysis shows a similar magnitude for the combined standard uncertainty of such measurements.
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Affiliation(s)
- Fabian Kugel
- West German Proton Therapy Centre Essen (WPE), Essen, Germany; University Hospital Essen, Essen, Germany; West German Cancer Centre (WTZ), Essen, Germany; Department of Particle Therapy, Essen, Germany; Faculty of Physics, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Jörg Wulff
- West German Proton Therapy Centre Essen (WPE), Essen, Germany; University Hospital Essen, Essen, Germany; West German Cancer Centre (WTZ), Essen, Germany; Department of Particle Therapy, Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen (WPE), Essen, Germany; University Hospital Essen, Essen, Germany; West German Cancer Centre (WTZ), Essen, Germany; Department of Particle Therapy, Essen, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany; Department of Physics, TU Dortmund University, Dortmund, Germany
| | | | - Jana Kretschmer
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl-von-Ossietzky University, Oldenburg, Germany; Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Leonie Brodbek
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl-von-Ossietzky University, Oldenburg, Germany; Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; EBG MedAustron GmbH, Marie Curie-Straße 5, A-2700, Wiener Neustadt, Austria
| | - Carina Behrends
- West German Proton Therapy Centre Essen (WPE), Essen, Germany; University Hospital Essen, Essen, Germany; West German Cancer Centre (WTZ), Essen, Germany; Department of Particle Therapy, Essen, Germany; Department of Physics, TU Dortmund University, Dortmund, Germany
| | - Nico Verbeek
- West German Proton Therapy Centre Essen (WPE), Essen, Germany; University Hospital Essen, Essen, Germany; West German Cancer Centre (WTZ), Essen, Germany; Department of Particle Therapy, Essen, Germany
| | - Hui Khee Looe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl-von-Ossietzky University, Oldenburg, Germany
| | - Björn Poppe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl-von-Ossietzky University, Oldenburg, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen (WPE), Essen, Germany; University Hospital Essen, Essen, Germany; West German Cancer Centre (WTZ), Essen, Germany; Department of Particle Therapy, Essen, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany
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2
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Holm KM, Yukihara EG, Ahmed MF, Greilich S, Jäkel O. Triple channel analysis of Gafchromic EBT3 irradiated with clinical carbon-ion beams. Phys Med 2021; 87:123-130. [PMID: 34146794 DOI: 10.1016/j.ejmp.2021.06.009] [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: 12/14/2020] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 11/16/2022] Open
Abstract
Self-developing radiochromic film is widely used in radiotherapy QA procedures. To compensate for typical film inhomogeneities, the triple channel analysis method is commonly used for photon-irradiated film. We investigated the applicability of this method for GafchromicTMEBT3 (Ashland) film irradiated with a clinically used carbon-ion beam. Calibration curves were taken from EBT3 film specimens irradiated with monoenergetic carbon-ion beams of different doses. Measurements of the lateral field shape and homogeneity were performed in the middle of a passively modulated spread-out Bragg peak and compared to simultaneous characterization by means of a 2D ionization chamber array. Additional measurements to investigate the applicability of EBT3 for quality assurance (QA) measurement in carbon-ion beams were performed. The triple-channel analysis reduced the relative standard deviation of the doses in a uniform carbon ion field by 30% (from 1.9% to 1.3%) and reduced the maximum deviation by almost a factor of 3 (from 28.6% to 9.8%), demonstrating the elimination of film artifacts. The corrected film signal showed considerably improved image quality and quantitative agreement with the ionization chamber data, thus providing a clear rationale for the usage of the triple channel analysis in carbon-beam QA.
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Affiliation(s)
- Kim Marina Holm
- Department of Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, Braunschweig D-38116, Germany; Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany; Department of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, Heidelberg D-69120, Germany.
| | - Eduardo G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute, Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Md Foiez Ahmed
- Sun Nuclear Corporation, 3275 Suntree Blvd, Melbourne, Florida 32940, USA
| | - Steffen Greilich
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Oliver Jäkel
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany; Heidelberg Ion Beam Therapy Center (HIT), University Hospital Heidelberg, Im Neuenheimer Feld 450, Heidelberg D-69120, Germany
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3
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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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4
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Bolsa-Ferruz M, Palmans H, Boersma D, Stock M, Grevillot L. Monte Carlo computation of 3D distributions of stopping power ratios in light ion beam therapy using GATE-RTion. Med Phys 2021; 48:2580-2591. [PMID: 33465819 DOI: 10.1002/mp.14726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/11/2020] [Accepted: 12/20/2020] [Indexed: 12/18/2022] Open
Abstract
PURPOSE This paper presents a novel method for the calculation of three-dimensional (3D) Bragg-Gray water-to-detector stopping power ratio (sw,det ) distributions for proton and carbon ion beams. METHODS Contrary to previously published fluence-based calculations of the stopping power ratio, the sw,det calculation method used in this work is based on the specific way GATE/Geant4 scores the energy deposition. It only requires the use of the so-called DoseActor, as available in GATE, for the calculation of the sw,det at any point of a 3D dose distribution. The simulations are performed using GATE-RTion v1.0, a dedicated GATE release that was validated for the clinical use in light ion beam therapy. RESULTS The Bragg-Gray water-to-air stopping power ratio (sw,air ) was calculated for monoenergetic proton and carbon ion beams with the default stopping power data in GATE-RTion v1.0 and the new ICRU90 recommendation. The sw,air differences between the use of the default and the ICRU90 configuration were 0.6% and 5.4% at the physical range (R80 - 80% dose level in the distal dose fall-off) for a 70 MeV proton beam and a 120 MeV/u carbon ion beam, respectively. For protons, the sw,det results for lithium fluoride, silicon, gadolinium oxysulfide, and the active layer material of EBT2 (radiochromic film) were compared with the literature and a reasonable agreement was found. For a real patient treatment plan, the 3D distributions of sw,det in proton beams were calculated. CONCLUSIONS Our method was validated by comparison with available literature data. Its equivalence with Bragg-Gray cavity theory was demonstrated mathematically. The capability of GATE-RTion v1.0 for the sw,det calculation at any point of a 3D dose distribution for simple and complex proton and carbon ion plans was presented.
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Affiliation(s)
- Marta Bolsa-Ferruz
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria
| | - Hugo Palmans
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria.,Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, UK
| | - David Boersma
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria.,ACMIT Gmbh, Viktor-Kaplan-Straße 2/1, Wiener Neustadt, A-2700, Austria
| | - Markus Stock
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria
| | - Loïc Grevillot
- MedAustron Ion Therapy Center, Marie Curie-Straße 5, Wiener Neustadt, A-2700, Austria
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5
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Verbeek N, Wulff J, Bäumer C, Smyczek S, Timmermann B, Brualla L. Single pencil beam benchmark of a module for Monte Carlo simulation of proton transport in the PENELOPE code. Med Phys 2020; 48:456-476. [PMID: 33217026 DOI: 10.1002/mp.14598] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND AND PURPOSE PENH is a recently coded module for simulation of proton transport in conjunction with the Monte Carlo code PENELOPE. PENELOPE applies class II simulation to all type of interactions, in particular, to elastic collisions. PENH uses calculated differential cross sections for proton elastic collisions that include electron screening effects as well as nuclear structure effects. Proton-induced nuclear reactions are simulated from information in the ENDF-6 database or from alternative nuclear databases in ENDF format. The purpose of this work is to benchmark this module by simulating absorbed dose distributions from a single finite spot size proton pencil beam in water. MATERIALS AND METHODS Monte Carlo simulations with PENH are compared with simulation results from TOPAS Monte Carlo (v3.1p2) and RayStation Monte Carlo (v6). Different beam models are examined in terms of mean energy and energy spread to match the measured profiles. The phase-space file is derived from experimental measurements. Simulated absorbed dose distributions are compared to experimental data obtained with the ionization chamber array MatriXX 2D detector (IBA Dosimetry) in a water tank. The experiments were conducted with a clinical IBA pencil beam scanning dedicated nozzle. In all simulations a Fermi-Eyges phase-space representation of a single finite spot size proton pencil beam is used. RESULTS In general, there is a good agreement between simulated results and experimental data up to a distance of 3 cm from the central axis. In the core region (region where the dose is more than 10% of the maximum dose) PENH shows, overall, the smallest deviations from experimental data, with the largest radial rms (root mean square) smaller than 0.2. The results achieved by TOPAS and RayStation in that region are very close to those of PENH. For the halo region, that is the area of the dose distribution outside the core region reaching down to 0.01% of the maximum intensity, the largest rms achieved by TOPAS is always smaller than 0.5, yielding better results than the rest of the codes. CONCLUSION The physics modeling of the PENELOPE/PENH code yields results consistent with measurements in the dose range relevant for proton therapy. The discrepancies between PENH appearing at distances larger than 3 cm from the central-beam axis are accountable to the lack of neutron simulation in this code. In contradistinction, TOPAS has a better agreement with experimental data at large distances from the central-beam axis because of the simulation of neutrons.
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Affiliation(s)
- Nico Verbeek
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany
| | - Jörg Wulff
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany.,Radiation Oncology and Imaging, German Cancer Consortium DKTK, Heidelberg, Germany.,Technische Universität Dortmund, Otto-Hahn-Str. 4a, Dortmund, 44227, Germany
| | - Sabrina Smyczek
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany.,Faculty of Physics, Heinrich Heine University Düsseldorf HHU, Düsseldorf, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany.,Radiation Oncology and Imaging, German Cancer Consortium DKTK, Heidelberg, Germany.,Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Lorenzo Brualla
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany
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6
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Niroomand‐Rad A, Chiu‐Tsao S, Grams MP, Lewis DF, Soares CG, Van Battum LJ, Das IJ, Trichter S, Kissick MW, Massillon‐JL G, Alvarez PE, Chan MF. Report of AAPM Task Group 235 Radiochromic Film Dosimetry: An Update to TG‐55. Med Phys 2020; 47:5986-6025. [DOI: 10.1002/mp.14497] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Affiliation(s)
| | | | | | | | | | | | - Indra J. Das
- Radiation Oncology Northwestern University Memorial Hospital Chicago IL USA
| | - Samuel Trichter
- New York‐Presbyterian HospitalWeill Cornell Medical Center New York NY USA
| | | | - Guerda Massillon‐JL
- Instituto de Fisica Universidad Nacional Autonoma de Mexico Mexico City Mexico
| | - Paola E. Alvarez
- Imaging and Radiation Oncology Core MD Anderson Cancer Center Houston TX USA
| | - Maria F. Chan
- Memorial Sloan Kettering Cancer Center Basking Ridge NJ USA
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Kretschmer J, Dulkys A, Brodbek L, Stelljes TS, Looe HK, Poppe B. Monte Carlo simulated beam quality and perturbation correction factors for ionization chambers in monoenergetic proton beams. Med Phys 2020; 47:5890-5905. [DOI: 10.1002/mp.14499] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/19/2020] [Accepted: 09/08/2020] [Indexed: 11/11/2022] Open
Affiliation(s)
- Jana Kretschmer
- University Clinic for Medical Radiation Physics Medical Campus Pius HospitalCarl‐von‐Ossietzky University Oldenburg Germany
| | - Anna Dulkys
- University Clinic for Medical Radiation Physics Medical Campus Pius HospitalCarl‐von‐Ossietzky University Oldenburg Germany
- Department of Radiation Therapy Helios Clinics Schwerin Schwerin Germany
| | - Leonie Brodbek
- University Clinic for Medical Radiation Physics Medical Campus Pius HospitalCarl‐von‐Ossietzky University Oldenburg Germany
- Department of Radiation Oncology University Medical Center GroningenUniversity of Groningen Groningen The Netherlands
| | - Tenzin Sonam Stelljes
- University Clinic for Medical Radiation Physics Medical Campus Pius HospitalCarl‐von‐Ossietzky University Oldenburg Germany
| | - Hui Khee Looe
- University Clinic for Medical Radiation Physics Medical Campus Pius HospitalCarl‐von‐Ossietzky University Oldenburg Germany
| | - Björn Poppe
- University Clinic for Medical Radiation Physics Medical Campus Pius HospitalCarl‐von‐Ossietzky University Oldenburg Germany
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8
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Gomà C, Sterpin E. Monte Carlo calculation of beam quality correction factors in proton beams using PENH. ACTA ACUST UNITED AC 2019; 64:185009. [DOI: 10.1088/1361-6560/ab3b94] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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9
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Baumann KS, Horst F, Zink K, Gomà C. Comparison of penh, fluka, and Geant4/topas for absorbed dose calculations in air cavities representing ionization chambers in high-energy photon and proton beams. Med Phys 2019; 46:4639-4653. [PMID: 31350915 PMCID: PMC6851981 DOI: 10.1002/mp.13737] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 07/01/2019] [Accepted: 07/16/2019] [Indexed: 12/16/2022] Open
Abstract
Purpose The purpose of this work is to analyze whether the Monte Carlo codes penh, fluka, and geant4/topas are suitable to calculate absorbed doses and fQ/fQ0 ratios in therapeutic high‐energy photon and proton beams. Methods We used penh, fluka, geant4/topas, and egsnrc to calculate the absorbed dose to water in a reference water cavity and the absorbed dose to air in two air cavities representative of a plane‐parallel and a cylindrical ionization chamber in a 1.25 MeV photon beam and a 150 MeV proton beam — egsnrc was only used for the photon beam calculations. The physics and transport settings in each code were adjusted to simulate the particle transport as detailed as reasonably possible. From these absorbed doses, fQ0 factors, fQ factors, and fQ/fQ0 ratios (which are the basis of Monte Carlo calculated beam quality correction factors kQ,Q0) were calculated and compared between the codes. Additionally, we calculated the spectra of primary particles and secondary electrons in the reference water cavity, as well as the integrated depth–dose curve of 150 MeV protons in water. Results The absorbed doses agreed within 1.4% or better between the individual codes for both the photon and proton simulations. The fQ0 and fQ factors agreed within 0.5% or better for the individual codes for both beam qualities. The resulting fQ/fQ0 ratios for 150 MeV protons agreed within 0.7% or better. For the 1.25 MeV photon beam, the spectra of photons and secondary electrons agreed almost perfectly. For the 150 MeV proton simulation, we observed differences in the spectra of secondary protons whereas the spectra of primary protons and low‐energy delta electrons also agreed almost perfectly. The first 2 mm of the entrance channel of the 150 MeV proton Bragg curve agreed almost perfectly while for greater depths, the differences in the integrated dose were up to 1.5%. Conclusion penh, fluka, and geant4/topas are capable of calculating beam quality correction factors in proton beams. The differences in the fQ0 and fQ factors between the codes are 0.5% at maximum. The differences in the fQ/fQ0 ratios are 0.7% at maximum.
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Affiliation(s)
- Kilian-Simon Baumann
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany.,Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany
| | - Felix Horst
- Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany.,GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - Klemens Zink
- Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany.,Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany.,Frankfurt Institute for Advanced Studies (FIAS), Frankfurt, Germany
| | - Carles Gomà
- Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
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10
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Hartmann GH, Andreo P. Fluence calculation methods in Monte Carlo dosimetry simulations. Z Med Phys 2019; 29:239-248. [DOI: 10.1016/j.zemedi.2018.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/04/2018] [Accepted: 08/26/2018] [Indexed: 11/25/2022]
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11
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Shi C, Chen CC, Mah D, Chan MF. Monte Carlo calculation of the mass stopping power of EBT3 and EBT-XD films for protons for energy ranges of 50-400 MeV. PRECISION RADIATION ONCOLOGY 2019; 2:106-113. [PMID: 31131334 PMCID: PMC6532660 DOI: 10.1002/pro6.55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Objective The goal of the present study was to calculate the continuous slowing down approximation (CDSA) ranges and derive mass stopping power for EBT3 and EBT-XD films for therapeutic protons energy ranges of 50-400 MeV. Methods The MCNPX and TRansport of Ions in Matter (TRIM) Monte Carlo codes were used in this study. Utilizing the published International Commission on Radiation Units and Measurement 49 data for the water mass stopping power and CSDA ranges, the mass stopping powers of EBT3 and EBT-XD films were derived using the approximation proposed by Newhauser and Zhang in 2009. Results The calculated CSDA ranges by MCNPX and TRIM in water were first benchmarked to International Commission on Radiation Units and Measurement 49 published data for water, and found to be within 1% with a 1.4-mm maximum difference. The calculated CSDA values in EBT3 film, compared with the measured CSDA ranges in the EBT3 film, were within 2% of the calculated values with a 3-mm maximum difference. The MCNPX and TRIM results for CSDA ranges agreed with each other to within 2.7% for EBT3 film and 4.4% for EBT-XD film. The overall uncertainties of the MCNPX and TRIM-derived CSDA ranges were 3% and 1.3%, respectively. Conclusion The mass stopping powers for Gafchromic EBT3 and EBT-XD films were derived.
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Affiliation(s)
- Chengyu Shi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, Basking Ridge, New Jersey, USA
| | - Chin-Cheng Chen
- Department of Radiation Physics, ProCure Proton Center, Somerset, New Jersey, USA
| | - Dennis Mah
- Department of Radiation Physics, ProCure Proton Center, Somerset, New Jersey, USA
| | - Maria F Chan
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, Basking Ridge, New Jersey, USA
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Castriconi R, Ciocca M, Mirandola A, Sini C, Broggi S, Schwarz M, Fracchiolla F, Martišíková M, Aricò G, Mettivier G, Russo P. Dose–response of EBT3 radiochromic films to proton and carbon ion clinical beams. Phys Med Biol 2016; 62:377-393. [DOI: 10.1088/1361-6560/aa5078] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Gomà C, Lorentini S, Meer D, Safai S. Reply to comment on 'Proton beam monitor chamber calibration'. Phys Med Biol 2016; 61:6594-601. [PMID: 27535895 DOI: 10.1088/0031-9155/61/17/6594] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This reply shows that the discrepancy of about 3% between Faraday cup dosimetry and reference dosimetry using a cylindrical ionization chamber found in Gomà (2014 Phys. Med. Biol. 59 4961-71) seems to be due to an overestimation of the beam quality correction factors tabulated in IAEA TRS-398 for the cylindrical chamber used, rather than to 'unresolved problems with Faraday cup dosimetry', as suggested by Palmans and Vatnitsky (2016 Phys. Med. Biol. 61 6585-93). Furthermore, this work shows that a good agreement between reference dosimetry and Faraday cup dosimetry is possible, provided accurate beam quality correction factors for proton beams are used. The review on W air values presented by Palmans and Vatnitsky is believed to be inaccurate, as it is based on the imprecise assumption of ionization chamber perturbation correction factors in proton beams being equal to unity.
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Affiliation(s)
- Carles Gomà
- Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium
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Lourenço A, Thomas R, Bouchard H, Kacperek A, Vondracek V, Royle G, Palmans H. Experimental and Monte Carlo studies of fluence corrections for graphite calorimetry in low- and high-energy clinical proton beams. Med Phys 2016; 43:4122. [DOI: 10.1118/1.4951733] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Faddegon BA, Shin J, Castenada CM, Ramos-Méndez J, Daftari IK. Experimental depth dose curves of a 67.5 MeV proton beam for benchmarking and validation of Monte Carlo simulation. Med Phys 2016; 42:4199-210. [PMID: 26133619 DOI: 10.1118/1.4922501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To measure depth dose curves for a 67.5 ± 0.1 MeV proton beam for benchmarking and validation of Monte Carlo simulation. METHODS Depth dose curves were measured in 2 beam lines. Protons in the raw beam line traversed a Ta scattering foil, 0.1016 or 0.381 mm thick, a secondary emission monitor comprised of thin Al foils, and a thin Kapton exit window. The beam energy and peak width and the composition and density of material traversed by the beam were known with sufficient accuracy to permit benchmark quality measurements. Diodes for charged particle dosimetry from two different manufacturers were used to scan the depth dose curves with 0.003 mm depth reproducibility in a water tank placed 300 mm from the exit window. Depth in water was determined with an uncertainty of 0.15 mm, including the uncertainty in the water equivalent depth of the sensitive volume of the detector. Parallel-plate chambers were used to verify the accuracy of the shape of the Bragg peak and the peak-to-plateau ratio measured with the diodes. The uncertainty in the measured peak-to-plateau ratio was 4%. Depth dose curves were also measured with a diode for a Bragg curve and treatment beam spread out Bragg peak (SOBP) on the beam line used for eye treatment. The measurements were compared to Monte Carlo simulation done with geant4 using topas. RESULTS The 80% dose at the distal side of the Bragg peak for the thinner foil was at 37.47 ± 0.11 mm (average of measurement with diodes from two different manufacturers), compared to the simulated value of 37.20 mm. The 80% dose for the thicker foil was at 35.08 ± 0.15 mm, compared to the simulated value of 34.90 mm. The measured peak-to-plateau ratio was within one standard deviation experimental uncertainty of the simulated result for the thinnest foil and two standard deviations for the thickest foil. It was necessary to include the collimation in the simulation, which had a more pronounced effect on the peak-to-plateau ratio for the thicker foil. The treatment beam, being unfocussed, had a broader Bragg peak than the raw beam. A 1.3 ± 0.1 MeV FWHM peak width in the energy distribution was used in the simulation to match the Bragg peak width. An additional 1.3-2.24 mm of water in the water column was required over the nominal values to match the measured depth penetration. CONCLUSIONS The proton Bragg curve measured for the 0.1016 mm thick Ta foil provided the most accurate benchmark, having a low contribution of proton scatter from upstream of the water tank. The accuracy was 0.15% in measured beam energy and 0.3% in measured depth penetration at the Bragg peak. The depth of the distal edge of the Bragg peak in the simulation fell short of measurement, suggesting that the mean ionization potential of water is 2-5 eV higher than the 78 eV used in the stopping power calculation for the simulation. The eye treatment beam line depth dose curves provide validation of Monte Carlo simulation of a Bragg curve and SOBP with 4%/2 mm accuracy.
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Affiliation(s)
- Bruce A Faddegon
- Department of Radiation Oncology, University of California San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143
| | - Jungwook Shin
- St. Jude Children's Research Hospital, 252 Danny Thomas Place, Memphis, Tennessee 38105
| | - Carlos M Castenada
- Crocker Nuclear Laboratory, University of California Davis, 1 Shields Avenue, Davis, California 95616
| | - José Ramos-Méndez
- Department of Radiation Oncology, University of California San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143
| | - Inder K Daftari
- Department of Radiation Oncology, University of California San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143
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Gomà C, Andreo P, Sempau J. Monte Carlo calculation of beam quality correction factors in proton beams using detailed simulation of ionization chambers. Phys Med Biol 2016; 61:2389-406. [DOI: 10.1088/0031-9155/61/6/2389] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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The role of a microDiamond detector in the dosimetry of proton pencil beams. Z Med Phys 2016; 26:88-94. [DOI: 10.1016/j.zemedi.2015.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 07/14/2015] [Accepted: 08/05/2015] [Indexed: 11/22/2022]
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Abstract
The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences-of the order of 3%-were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth-i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers-rather than cylindrical chambers-for the reference dosimetry of pseudo-monoenergetic proton beams.
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Affiliation(s)
- C Gomà
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland. Department of Physics, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
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Andreo P, Wulff J, Burns DT, Palmans H. Consistency in reference radiotherapy dosimetry: resolution of an apparent conundrum when60Co is the reference quality for charged-particle and photon beams. Phys Med Biol 2013; 58:6593-621. [DOI: 10.1088/0031-9155/58/19/6593] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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