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Geser FA, Stabilini A, Christensen JB, Muñoz ID, Yukihara EG, Jäkel O, Vedelago J. A Monte Carlo study on the secondary neutron generation by oxygen ion beams for radiotherapy and its comparison to lighter ions. Phys Med Biol 2024; 69:015027. [PMID: 37995363 DOI: 10.1088/1361-6560/ad0f45] [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: 08/16/2023] [Accepted: 11/23/2023] [Indexed: 11/25/2023]
Abstract
Objective.To study the secondary neutrons generated by primary oxygen beams for cancer treatment and compare the results to those from primary protons, helium, and carbon ions. This information can provide useful insight into the positioning of neutron detectors in phantom for future experimental dose assessments.Approach.Mono-energetic oxygen beams and spread-out Bragg peaks were simulated using the Monte Carlo particle transport codesFLUktuierende KAskade, tool for particle simulation, and Monte Carlo N-Particle, with energies within the therapeutic range. The energy and angular distribution of the secondary neutrons were quantified.Main results.The secondary neutron spectra generated by primary oxygen beams present the same qualitative trend as for other primary ions. The energy distributions resemble continuous spectra with one peak in the thermal/epithermal region, and one other peak in the fast/relativistic region, with the most probable energy ranging from 94 up to 277 MeV and maximum energies exceeding 500 MeV. The angular distribution of the secondary neutrons is mainly downstream-directed for the fast/relativistic energies, whereas the thermal/epithermal neutrons present a more isotropic propagation. When comparing the four different primary ions, there is a significant increase in the most probable energy as well as the number of secondary neutrons per primary particle when increasing the mass of the primaries.Significance.Most previous studies have only presented results of secondary neutrons generated by primary proton beams. In this work, secondary neutrons generated by primary oxygen beams are presented, and the obtained energy and angular spectra are added as supplementary material. Furthermore, a comparison of the secondary neutron generation by the different primary ions is given, which can be used as the starting point for future studies on treatment plan comparison and secondary neutron dose optimisation. The distal penumbra after the maximum dose deposition appears to be a suitable location for in-phantom dose assessments.
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Affiliation(s)
- Federico A Geser
- Department of Radiation Safety and Security, Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Alberto Stabilini
- Department of Radiation Safety and Security, Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Jeppe B Christensen
- Department of Radiation Safety and Security, Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Iván D Muñoz
- Department of Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, Heidelberg D-69120, 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), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Eduardo G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - 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), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Heidelberg Ion Beam Therapy Center (HIT), Department of Radiation Oncology, University Hospital Heidelberg (UKHD), Im Neuenheimer Feld 450, Heidelberg D-69120, Germany
| | - José Vedelago
- 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), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Im Neuenheimer Feld 400, Heidelberg D-69120, Germany
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2
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Romero-Expósito M, Liszka M, Christou A, Toma-Dasu I, Dasu A. Range shifter contribution to neutron exposure of patients undergoing proton pencil beam scanning. Med Phys 2023. [PMID: 38112191 DOI: 10.1002/mp.16897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/30/2023] [Accepted: 12/03/2023] [Indexed: 12/21/2023] Open
Abstract
BACKGROUND Superficial targets require the use of the lowest energies within the available energy range in proton pencil-beam scanning (PBS) technique. However, the lower efficiency of the energy selection system at these energies and the requirement of a greater number of layers may represent disadvantages for this approach. The alternative is to use a range shifter (RS) at nozzle exit. However, one of the concerns of using this beamline element is that it becomes an additional source of neutrons that could irradiate organs situated far from the target. PURPOSE The purpose of this study is to assess the increase in neutron dose due to the RS in proton PBS technique. Additionally, an analytical model for the neutron production is tested. METHODS Two clinical plans, designed to achieve identical target coverage, were created for an anthropomorphic phantom. These plans consisted of a lateral field delivering an absorbed dose of 60 Gy (RBE) to the target. One of the plans employed the RS. The MCNP code was used to simulate the plans, evaluating the distribution of neutron dose equivalent (Hn ) and the equivalent dose in organ. In the plan with the RS plan, neutron production from both the patient and the RS were assessed separately. Hn values were also fitted versus the distance to field edge using a Gaussian function. RESULTS Hn per prescription dose, in the plan using the RS, ranged between 1.4 and 3.7 mSv/Gy at the field edge, whereas doses at 40 cm from the edge ranged from 9.9 to 32 μSv/Gy. These values are 1.2 to 10 times higher compared to those obtained without the RS. Both this factor and the contribution of neutrons originating from the RS increases with the distance from field edge. A triple-Gaussian function was able to reproduce the equivalent dose in organs within a factor of 2, although underestimating the values. CONCLUSIONS The dose deposited in the patient by the neutrons originating from the RS predominantly affects areas away from the target (beyond approximately 25 cm from field edge), resulting in a neutron dose equivalent of the order of mSv. This indicates an overall low neutron contribution from the use of RS in PBS.
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Affiliation(s)
- Maite Romero-Expósito
- The Skandion Clinic, Uppsala, Sweden
- Oncology Pathology Department, Karolinska Institutet, Solna, Sweden
| | | | | | - Iuliana Toma-Dasu
- Oncology Pathology Department, Karolinska Institutet, Solna, Sweden
- Medical Radiation Physics, Stockholm University, Stockholm, Sweden
| | - Alexandru Dasu
- The Skandion Clinic, Uppsala, Sweden
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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3
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Colson D, Blommaert J, Poels K, De Saint-Hubert M, Reniers B, Depuydt T. Extended in-field and out-of-field validation of a compact Monte Carlo model of an IBA PROTEUS ®ONE proton beam in TOPAS/GEANT4. Phys Med Biol 2023; 68:21NT02. [PMID: 37844576 DOI: 10.1088/1361-6560/ad03a9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 10/16/2023] [Indexed: 10/18/2023]
Abstract
Objective:This study evaluates a compact Monte Carlo (MC) model of a pencil beam scanning clinical proton beam using TOPAS to estimate the dose out-of-field (OOF). Compact modelling means that the model starts from a pristine proton beam at the nozzle exit, customised based on acceptance and commissioning data, instead of modelling the full treatment head and room.Approach: First, in-field validation tests were performed. Then, the OOF dose was validated in an RW3 phantom with bubble detectors for personal neutron dosimetry (measuring the neutron dose equivalent) and thermoluminiescent detectors (measuring the absorbed dose by protons and gammas). Measurements were performed at 15 and 35 cm from the distal edge of the field for five different irradiation plans, covering different beam orientations, proton energies and a 40 mm range shifter. TOPAS simulations were performed with QGSP Binary Cascade HP (BIC) and QGSP Bertini HP (Bertini) hadron physics lists.Main results: In-field validation shows that MC simulations agree with point dose measurements within -2.5 % and +1.5 % at locations on- and off-axis and before, in and after the Bragg peak or plateau. The gamma passing rate 2%/3mm of four simulated treatment plans compared to the dose distribution calculated by the TPS exceeds 97 % agreement score. OOF dose simulations showed an average overestimation of 27 % of the neutron dose equivalent for the BIC hadron physics list and an average underestimation of 20 % for the Bertini hadron physics list. The simulated absorbed dose of protons and gammas showed a systematic underestimation which was on average 21 % and 51 % for BIC and Bertini respectively.Significance: Our study demonstrates that a compact MC model can reliably produce in-field data, while out-of-field dose data are within the uncertainties of the detector systems and MC simulations nuclear models, and do so with shorter modelling and faster calculation time.
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Affiliation(s)
- Dries Colson
- Hasselt University, Faculty of Engineering Technology - Nuclear Technology (NuTeC), Hasselt, Belgium
| | | | - Kenneth Poels
- University Hospitals Leuven, Department of Radiation Oncology, Leuven, Belgium
| | - Marijke De Saint-Hubert
- Belgian Nuclear Research Centre (SCK CEN), Research in Dosimetric Applications, Mol, Belgium
| | - Brigitte Reniers
- Hasselt University, Faculty of Engineering Technology - Nuclear Technology (NuTeC), Hasselt, Belgium
| | - Tom Depuydt
- KU Leuven, department of Oncology, Leuven, Belgium
- University Hospitals Leuven, Department of Radiation Oncology, Leuven, Belgium
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4
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Borja-Lloret M, Barrientos L, Bernabéu J, Lacasta C, Muñoz E, Ros A, Roser J, Viegas R, Llosá G. Influence of the background in Compton camera images for proton therapy treatment monitoring. Phys Med Biol 2023; 68:144001. [PMID: 37339665 DOI: 10.1088/1361-6560/ace024] [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: 02/03/2023] [Accepted: 06/20/2023] [Indexed: 06/22/2023]
Abstract
Objective. Background events are one of the most relevant contributions to image degradation in Compton camera imaging for hadron therapy treatment monitoring. A study of the background and its contribution to image degradation is important to define future strategies to reduce the background in the system.Approach. In this simulation study, the percentage of different kinds of events and their contribution to the reconstructed image in a two-layer Compton camera have been evaluated. To this end, GATE v8.2 simulations of a proton beam impinging on a PMMA phantom have been carried out, for different proton beam energies and at different beam intensities.Main results. For a simulated Compton camera made of Lanthanum (III) Bromide monolithic crystals, coincidences caused by neutrons arriving from the phantom are the most common type of background produced by secondary radiations in the Compton camera, causing between 13% and 33% of the detected coincidences, depending on the beam energy. Results also show that random coincidences are a significant cause of image degradation at high beam intensities, and their influence in the reconstructed images is studied for values of the time coincidence windows from 500 ps to 100 ns.Significance. Results indicate the timing capabilities required to retrieve the fall-off position with good precision. Still, the noise observed in the image when no randoms are considered make us consider further background rejection methods.
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Affiliation(s)
- M Borja-Lloret
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - L Barrientos
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - J Bernabéu
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - C Lacasta
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - E Muñoz
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - A Ros
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - J Roser
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - R Viegas
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
| | - G Llosá
- Institut de Física Corpuscular (IFIC), CSIC-UV, València, Spain
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5
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Pazzaglia S, Eidemüller M, Lumniczky K, Mancuso M, Ramadan R, Stolarczyk L, Moertl S. Out-of-field effects: lessons learned from partial body exposure. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2022; 61:485-504. [PMID: 36001144 PMCID: PMC9722818 DOI: 10.1007/s00411-022-00988-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/03/2022] [Indexed: 05/27/2023]
Abstract
Partial body exposure and inhomogeneous dose delivery are features of the majority of medical and occupational exposure situations. However, mounting evidence indicates that the effects of partial body exposure are not limited to the irradiated area but also have systemic effects that are propagated outside the irradiated field. It was the aim of the "Partial body exposure" session within the MELODI workshop 2020 to discuss recent developments and insights into this field by covering clinical, epidemiological, dosimetric as well as mechanistic aspects. Especially the impact of out-of-field effects on dysfunctions of immune cells, cardiovascular diseases and effects on the brain were debated. The presentations at the workshop acknowledged the relevance of out-of-field effects as components of the cellular and organismal radiation response. Furthermore, their importance for the understanding of radiation-induced pathologies, for the discovery of early disease biomarkers and for the identification of high-risk organs after inhomogeneous exposure was emphasized. With the rapid advancement of clinical treatment modalities, including new dose rates and distributions a better understanding of individual health risk is urgently needed. To achieve this, a deeper mechanistic understanding of out-of-field effects in close connection to improved modelling was suggested as priorities for future research. This will support the amelioration of risk models and the personalization of risk assessments for cancer and non-cancer effects after partial body irradiation.
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Affiliation(s)
- S. Pazzaglia
- Laboratory of Biomedical Technologies, ENEA CR-Casaccia, Via Anguillarese 301, 00123 Rome, Italy
| | - M. Eidemüller
- Institute of Radiation Medicine, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - K. Lumniczky
- Department of Radiobiology and Radiohygiene, Unit of Radiation Medicine, National Public Health Centre, Albert Florian u. 2-6, 1097 Budapest, Hungary
| | - M. Mancuso
- Laboratory of Biomedical Technologies, ENEA CR-Casaccia, Via Anguillarese 301, 00123 Rome, Italy
| | - R. Ramadan
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - L. Stolarczyk
- Danish Centre for Particle Therapy, Palle Juul-Jensens Boulevard 25, 8200 Aarhus N, Denmark
| | - S. Moertl
- Federal Office for Radiation Protection, Ingolstädter Landstr. 1, 85764 Oberschleißheim, Germany
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6
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Van Hoey O, Stolarczyk L, Lillhök J, Eliasson L, Mojzeszek N, Liszka M, Alkhiat A, Mares V, Trompier F, Trinkl S, Martínez-Rovira I, Romero-Expósito M, Domingo C, Ploc O, Harrison R, Olko P. Simulation and experimental verification of ambient neutron doses in a pencil beam scanning proton therapy room as a function of treatment plan parameters. Front Oncol 2022; 12:903537. [PMID: 36158693 PMCID: PMC9494550 DOI: 10.3389/fonc.2022.903537] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/07/2022] [Indexed: 11/23/2022] Open
Abstract
Out-of-field patient doses in proton therapy are dominated by neutrons. Currently, they are not taken into account by treatment planning systems. There is an increasing need to include out-of-field doses in the dose calculation, especially when treating children, pregnant patients, and patients with implants. In response to this demand, this work presents the first steps towards a tool for the prediction of out-of-field neutron doses in pencil beam scanning proton therapy facilities. As a first step, a general Monte Carlo radiation transport model for simulation of out-of-field neutron doses was set up and successfully verified by comparison of simulated and measured ambient neutron dose equivalent and neutron fluence energy spectra around a solid water phantom irradiated with a variation of different treatment plan parameters. Simulations with the verified model enabled a detailed study of the variation of the neutron ambient dose equivalent with field size, range, modulation width, use of a range shifter, and position inside the treatment room. For future work, it is planned to use this verified model to simulate out-of-field neutron doses inside the phantom and to verify the simulation results by comparison with previous in-phantom measurement campaigns. Eventually, these verified simulations will be used to build a library and a corresponding tool to allow assessment of out-of-field neutron doses at pencil beam scanning proton therapy facilities.
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Affiliation(s)
- Olivier Van Hoey
- Belgian Nuclear Research Center (SCK CEN), Institute for Environment, Health and Safety (EHS), Mol, Belgium
- *Correspondence: Olivier Van Hoey,
| | - Liliana Stolarczyk
- Danish Centre for Particle Therapy, Aarhus University Hospital (AUH), Aarhus, Denmark
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
- The Skandion Clinic, Uppsala, Sweden
| | - Jan Lillhök
- Swedish Radiation Safety Authority, Solna, Sweden
| | - Linda Eliasson
- Department of Physics, Royal Institute of Technology (KTH), Stockholm, Sweden
| | - Natalia Mojzeszek
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
| | - Malgorzata Liszka
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
- The Skandion Clinic, Uppsala, Sweden
| | - Ali Alkhiat
- The Skandion Clinic, Uppsala, Sweden
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Vladimir Mares
- Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
| | - François Trompier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, Fontenay-aux-Roses, France
| | - Sebastian Trinkl
- Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
- Federal Office for Radiation Protection, Neuherberg, Germany
| | | | | | - Carles Domingo
- Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Ondrej Ploc
- Department of Radiation Dosimetry, Nuclear Physics Institute of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Roger Harrison
- Faculty of Medical Sciences, University of Newcastle upon Tyne, Newcastle Upon Tyne, United Kingdom
| | - Pawel Olko
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
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7
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Rabus H, Zankl M, Gómez-Ros JM, Villagrasa C, Eakins J, Huet C, Brkić H, Tanner R. Lessons learnt from the recent EURADOS intercomparisons in computational dosimetry. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Tanner R, Agosteo S, Rabus H. EURADOS working group 6, computational dosimetry, a history of promoting good practice via intercomparisons and training. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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9
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De Saint-Hubert M, Verbeek N, Bäumer C, Esser J, Wulff J, Nabha R, Van Hoey O, Dabin J, Stuckmann F, Vasi F, Radonic S, Boissonnat G, Schneider U, Rodriguez M, Timmermann B, Thierry-Chef I, Brualla L. Validation of a Monte Carlo Framework for Out-of-Field Dose Calculations in Proton Therapy. Front Oncol 2022; 12:882489. [PMID: 35756661 PMCID: PMC9213663 DOI: 10.3389/fonc.2022.882489] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022] Open
Abstract
Proton therapy enables to deliver highly conformed dose distributions owing to the characteristic Bragg peak and the finite range of protons. However, during proton therapy, secondary neutrons are created, which can travel long distances and deposit dose in out-of-field volumes. This out-of-field absorbed dose needs to be considered for radiation-induced secondary cancers, which are particularly relevant in the case of pediatric treatments. Unfortunately, no method exists in clinics for the computation of the out-of-field dose distributions in proton therapy. To help overcome this limitation, a computational tool has been developed based on the Monte Carlo code TOPAS. The purpose of this work is to evaluate the accuracy of this tool in comparison to experimental data obtained from an anthropomorphic phantom irradiation. An anthropomorphic phantom of a 5-year-old child (ATOM, CIRS) was irradiated for a brain tumor treatment in an IBA Proteus Plus facility using a pencil beam dedicated nozzle. The treatment consisted of three pencil beam scanning fields employing a lucite range shifter. Proton energies ranged from 100 to 165 MeV. A median dose of 50.4 Gy(RBE) with 1.8 Gy(RBE) per fraction was prescribed to the initial planning target volume (PTV), which was located in the cerebellum. Thermoluminescent detectors (TLDs), namely, Li-7-enriched LiF : Mg, Ti (MTS-7) type, were used to detect gamma radiation, which is produced by nuclear reactions, and secondary as well as recoil protons created out-of-field by secondary neutrons. Li-6-enriched LiF : Mg,Cu,P (MCP-6) was combined with Li-7-enriched MCP-7 to measure thermal neutrons. TLDs were calibrated in Co-60 and reported on absorbed dose in water per target dose (μGy/Gy) as well as thermal neutron dose equivalent per target dose (μSv/Gy). Additionally, bubble detectors for personal neutron dosimetry (BD-PND) were used for measuring neutrons (>50 keV), which were calibrated in a Cf-252 neutron beam to report on neutron dose equivalent dose data. The Monte Carlo code TOPAS (version 3.6) was run using a phase-space file containing 1010 histories reaching an average standard statistical uncertainty of less than 0.2% (coverage factor k = 1) on all voxels scoring more than 50% of the maximum dose. The primary beam was modeled following a Fermi–Eyges description of the spot envelope fitted to measurements. For the Monte Carlo simulation, the chemical composition of the tissues represented in ATOM was employed. The dose was tallied as dose-to-water, and data were normalized to the target dose (physical dose) to report on absorbed doses per target dose (mSv/Gy) or neutron dose equivalent per target dose (μSv/Gy), while also an estimate of the total organ dose was provided for a target dose of 50.4 Gy(RBE). Out-of-field doses showed absorbed doses that were 5 to 6 orders of magnitude lower than the target dose. The discrepancy between TLD data and the corresponding scored values in the Monte Carlo calculations involving proton and gamma contributions was on average 18%. The comparison between the neutron equivalent doses between the Monte Carlo simulation and the measured neutron doses was on average 8%. Organ dose calculations revealed the highest dose for the thyroid, which was 120 mSv, while other organ doses ranged from 18 mSv in the lungs to 0.6 mSv in the testes. The proposed computational method for routine calculation of the out-of-the-field dose in proton therapy produces results that are compatible with the experimental data and allow to calculate out-of-field organ doses during proton therapy.
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Affiliation(s)
- Marijke De Saint-Hubert
- Research in Dosimetric Applications, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Nico Verbeek
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,Radiation Oncology and Imaging, German Cancer Consortium DKTK, Heidelberg, Germany.,Department of Physics, TU Dortmund University, Dortmund, Germany
| | - Johannes Esser
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,Faculty of Mathematics and Science Institute of Physics and Medical Physics. Heinrich-Heine University, Düsseldorf, Germany
| | - Jörg Wulff
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany
| | - Racell Nabha
- Research in Dosimetric Applications, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Olivier Van Hoey
- Research in Dosimetric Applications, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Jérémie Dabin
- Research in Dosimetric Applications, Belgian Nuclear Research Center (SCK CEN), Mol, Belgium
| | - Florian Stuckmann
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Mathematics and Science Institute of Physics and Medical Physics. Heinrich-Heine University, Düsseldorf, Germany.,Klinikum Fulda GAG, Universitätsmedizin Marburg, Fulda, Zurich, Germany
| | - Fabiano Vasi
- Physik Institut, Universität Zürich, Zürich, Switzerland
| | | | | | - Uwe Schneider
- Physik Institut, Universität Zürich, Zürich, Switzerland
| | - Miguel Rodriguez
- Hospital Paitilla, Panama City, Panama.,Instituto de Investigaciones Cientificas y de Alta Tecnología INDICASAT-AIP, Panama City, Panama
| | - Beate Timmermann
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,Radiation Oncology and Imaging, German Cancer Consortium DKTK, Heidelberg, Germany.,Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Isabelle Thierry-Chef
- Radiation Programme, Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain.,University Pompeu Fabra, Barcelona, Spain.,CIBER Epidemiología y Salud Pública, Madrid, Spain
| | - Lorenzo Brualla
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany
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10
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Domingo C, Lagares JI, Romero-Expósito M, Sánchez-Nieto B, Nieto-Camero JJ, Terrón JA, Irazola L, Dasu A, Sánchez-Doblado F. Peripheral Organ Equivalent Dose Estimation Procedure in Proton Therapy. Front Oncol 2022; 12:882476. [PMID: 35692801 PMCID: PMC9176390 DOI: 10.3389/fonc.2022.882476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/19/2022] [Indexed: 11/23/2022] Open
Abstract
The aim of this work is to present a reproducible methodology for the evaluation of total equivalent doses in organs during proton therapy facilities. The methodology is based on measuring the dose equivalent in representative locations inside an anthropomorphic phantom where photon and neutron dosimeters were inserted. The Monte Carlo simulation was needed for obtaining neutron energy distribution inside the phantom. The methodology was implemented for a head irradiation case in the passive proton beam of iThemba Labs (South Africa). Thermoluminescent dosimeter (TLD)-600 and TLD-700 pairs were used as dosimeters inside the phantom and GEANT code for simulations. In addition, Bonner sphere spectrometry was performed inside the treatment room to obtain the neutron spectra, some relevant neutron dosimetric quantities per treatment Gy, and a percentual distribution of neutron fluence and ambient dose equivalent in four energy groups, at two locations. The neutron spectrum at one of those locations was also simulated so that a reasonable agreement between simulation and measurement allowed a validation of the simulation. Results showed that the total out-of-field dose equivalent inside the phantom ranged from 1.4 to 0.28 mSv/Gy, mainly due to the neutron contribution and with a small contribution from photons, 10% on average. The order of magnitude of the equivalent dose in organs was similar, displaying a slow reduction in values as the organ is farther from the target volume. These values were in agreement with those found by other authors in other passive beam facilities under similar irradiation and measurement conditions.
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Affiliation(s)
- Carles Domingo
- Departament de Fisica, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Juan Ignacio Lagares
- Unidad de Aplicaciones Médicas, Departamento de Tecnología, Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | | | | | | | - Jose Antonio Terrón
- Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla, Spain
| | - Leticia Irazola
- Servicio de Radiofísica y Protección Radiológica, Clínica Universidad de Navarra, Pamplona, Spain
| | - Alexandru Dasu
- The Skandion Clinic, Uppsala, Sweden.,Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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