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Shamsabadi R, Baghani HR. An inter-comparison between radiobiological characteristics of a commercial low-energy IORT system by Geant4-DNA and MCDS Monte Carlo codes. Int J Radiat Biol 2024; 100:1226-1235. [PMID: 38166191 DOI: 10.1080/09553002.2023.2295290] [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: 08/19/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 01/04/2024]
Abstract
INTRODUCTION The need for accurate relative biological effectiveness (RBE) estimation for low energy therapeutic X-rays (corresponding to 50 kV nominal energy of a commercial low-energy IORT system (INTRABEAM)) is a crucial issue due to increased radiobiological effects, respect to high energy photons. Modeling of radiation-induced DNA damage through Monte Carlo (MC) simulation approaches can give useful information. Hence, this study aimed to evaluate and compare RBE of low energy therapeutic X-rays using Geant4-DNA toolkit and Monte Carlo damage simulation (MCDS) code. MATERIALS AND METHODS RBE calculations were performed considering the emitted secondary electron spectra through interactions of low energy X-rays inside the medium. In Geant4-DNA, the DNA strand breaks were obtained by employing a B-DNA model in physical stage with 10.79 eV energy-threshold and the probability of hydroxyl radical's chemical reactions of about 0.13%. Furthermore, RBE estimations by MCDS code were performed under fully aerobic conditions. RESULTS Acquired results by two considered MC codes showed that the same trend is found for RBEDSB and RBESSB variations. Totally, a reasonable agreement between the calculated RBE values (both RBESSB and RBEDSB) existed between the two considered MC codes. The mean differences of 9.2% and 1.8% were obtained between the estimated RBESSB and RBEDSB values by two codes, respectively. CONCLUSION Based on the obtained results, it can be concluded that a tolerable accordance is found between the calculated RBEDSB values through MCDS and Geant4-DNA, a fact which appropriates both codes for RBE evaluations of low energy therapeutic X-rays, especially in the case of RBEDSB where lethal damages are regarded.
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Affiliation(s)
- Reza Shamsabadi
- Department of Physics, Hakim Sabzevari University, Sabzeoar, Iran
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2
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Tjelta J, Ytre-Hauge K, Lyngholm E, Handeland A, Henjum H, Stokkevåg C. Dose exposure to an adult present in the treatment room during pediatric pencil beam scanning proton therapy. Acta Oncol 2023; 62:1531-1535. [PMID: 37676843 DOI: 10.1080/0284186x.2023.2254924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023]
Affiliation(s)
- Johannes Tjelta
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | | | - Erlend Lyngholm
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Andreas Handeland
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Helge Henjum
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Camilla Stokkevåg
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
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3
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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: 12] [Impact Index Per Article: 6.0] [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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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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5
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Romero-Expósito M, Toma-Dasu I, Dasu A. Determining Out-of-Field Doses and Second Cancer Risk From Proton Therapy in Young Patients—An Overview. Front Oncol 2022; 12:892078. [PMID: 35712488 PMCID: PMC9197425 DOI: 10.3389/fonc.2022.892078] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Proton therapy has the potential to provide survival and tumor control outcomes comparable and frequently superior to photon therapy. This has led to a significant concern in the medical physics community on the risk for the induction of second cancers in all patients and especially in younger patients, as they are considered more radiosensitive than adults and have an even longer expected lifetime after treatment. Thus, our purpose is to present an overview of the research carried out on the evaluation of out-of-field doses linked to second cancer induction and the prediction of this risk. Most investigations consisted of Monte Carlo simulations in passive beam facilities for clinical scenarios. These works established that equivalent doses in organs could be up to 200 mSv or 900 mSv for a brain or a craniospinal treatment, respectively. The major contribution to this dose comes from the secondary neutrons produced in the beam line elements. Few works focused on scanned-beam facilities, but available data show that, for these facilities, equivalent doses could be between 2 and 50 times lower. Patient age is a relevant factor in the dose level, especially for younger patients (by means of the size of the body) and, in addition, in the predicted risk by models (due to the age dependence of the radiosensitivity). For risks, the sex of the patient also plays an important role, as female patients show higher sensitivity to radiation. Thus, predicted risks of craniospinal irradiation can range from 8% for a 15-year-old male patient to 58% for a 2-year-old female patient, using a risk model from a radiological protection field. These values must be taken with caution due to uncertainties in risk models, and then dosimetric evaluation of stray radiation becomes mandatory in order to complement epidemiological studies and be able to model appropriate dose–response functions for this dose range. In this sense, analytical models represent a useful tool and some models have been implemented to be used for young patients. Research carried out so far confirmed that proton beam therapy reduces the out-of-field doses and second cancer risk. However, further investigations may be required in scanned-beam delivery systems.
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Affiliation(s)
- Maite Romero-Expósito
- The Skandion Clinic, Uppsala, Sweden
- Oncology Pathology Department, Karolinska Institutet, Stockholm, Sweden
- *Correspondence: Maite Romero-Expósito,
| | - Iuliana Toma-Dasu
- Oncology Pathology Department, Karolinska Institutet, Stockholm, 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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6
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DNA damage response of haematopoietic stem and progenitor cells to high-LET neutron irradiation. Sci Rep 2021; 11:20854. [PMID: 34675263 PMCID: PMC8531011 DOI: 10.1038/s41598-021-00229-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/05/2021] [Indexed: 11/23/2022] Open
Abstract
The radiosensitivity of haematopoietic stem and progenitor cells (HSPCs) to neutron radiation remains largely underexplored, notwithstanding their potential role as target cells for radiation-induced leukemogenesis. New insights are required for radiation protection purposes, particularly for aviation, space missions, nuclear accidents and even particle therapy. In this study, HSPCs (CD34+CD38+ cells) were isolated from umbilical cord blood and irradiated with 60Co γ-rays (photons) and high energy p(66)/Be(40) neutrons. At 2 h post-irradiation, a significantly higher number of 1.28 ± 0.12 γ-H2AX foci/cell was observed after 0.5 Gy neutrons compared to 0.84 ± 0.14 foci/cell for photons, but this decreased to similar levels for both radiation qualities after 18 h. However, a significant difference in late apoptosis was observed with Annexin-V+/PI+ assay between photon and neutron irradiation at 18 h, 43.17 ± 6.10% versus 55.55 ± 4.87%, respectively. A significant increase in MN frequency was observed after both 0.5 and 1 Gy neutron irradiation compared to photons illustrating higher levels of neutron-induced cytogenetic damage, while there was no difference in the nuclear division index between both radiation qualities. The results point towards a higher induction of DNA damage after neutron irradiation in HSPCs followed by error-prone DNA repair, which contributes to genomic instability and a higher risk of leukemogenesis.
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7
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Hälg RA, Schneider U. Neutron dose and its measurement in proton therapy-current State of Knowledge. Br J Radiol 2020; 93:20190412. [PMID: 31868525 PMCID: PMC7066952 DOI: 10.1259/bjr.20190412] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 12/06/2019] [Accepted: 12/19/2019] [Indexed: 12/26/2022] Open
Abstract
Proton therapy has shown dosimetric advantages over conventional radiation therapy using photons. Although the integral dose for patients treated with proton therapy is low, concerns were raised about late effects like secondary cancer caused by dose depositions far away from the treated area. This is especially true for neutrons and therefore the stray dose contribution from neutrons in proton therapy is still being investigated. The higher biological effectiveness of neutrons compared to photons is the main cause of these concerns. The gold-standard in neutron dosimetry is measurements, but performing neutron measurements is challenging. Different approaches have been taken to overcome these difficulties, for instance with newly developed neutron detectors. Monte Carlo simulations is another common technique to assess the dose from secondary neutrons. Measurements and simulations are used to develop analytical models for fast neutron dose estimations. This article tries to summarize the developments in the different aspects of neutron dose in proton therapy since 2017. In general, low neutron doses have been reported, especially in active proton therapy. Although the published biological effectiveness of neutrons relative to photons regarding cancer induction is higher, it is unlikely that the neutron dose has a large impact on the second cancer risk of proton therapy patients.
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8
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Determination of fast neutron RBE using a fully mechanistic computational model. Appl Radiat Isot 2020; 156:108952. [DOI: 10.1016/j.apradiso.2019.108952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 10/11/2019] [Accepted: 10/21/2019] [Indexed: 11/19/2022]
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9
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Zabihi A, Incerti S, Francis Z, Forozani G, Semsarha F, Moslehi A, Rezaeian P, Bernal MA. Computational approach to determine the relative biological effectiveness of fast neutrons using the Geant4-DNA toolkit and a DNA atomic model from the Protein Data Bank. Phys Rev E 2019; 99:052404. [PMID: 31212425 DOI: 10.1103/physreve.99.052404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Indexed: 11/07/2022]
Abstract
This study proposes an innovative approach to estimate relative biological effectiveness (RBE) of fast neutrons using the Geant4 toolkit. The Geant4-DNA version cannot track heavy ions below 0.5 MeV/nucleon. In order to explore the impact of this issue, secondary particles are simulated instead of the primary low-energy neutrons. The Evaluated Nuclear Data File library is used to determine the cross sections for the elastic and inelastic interactions of neutrons with water and to find the contribution of each secondary particle spectrum. Two strategies are investigated in order to find the best possible approach and results. The first one takes into account only light particles, protons produced from elastic scattering, and α particles from inelastic scattering. Geantino particles are shot instead of heavy ions; hence all heavy ions are considered in the simulations, though their physical effects on DNA not. The second strategy takes into account all the heavy and light ions, although heavy ions cannot be tracked down to very low energies (E<0.5 MeV/nucleon). Our model is based on the combination of an atomic resolution DNA geometrical model and a Monte Carlo simulation toolkit for tracking particles. The atomic coordinates of the DNA double helix are extracted from the Protein Data Bank. Since secondary particle spectra are used instead of simulating the interaction of neutrons explicitly, this method reduces the computation times dramatically. Double-strand break induction is used as the end point for the estimation of the RBE of fast neutrons. ^{60}Co γ rays are used as the reference radiation quality. Both strategies succeed in reproducing the behavior of the RBE_{max} as a function of the incident neutron energy ranging from 0.1 to 14 MeV, including the position of its peak. A comparison of the behavior of the two strategies shows that for neutrons with energies less than 0.7 MeV, the effect of heavy ions would not be very significant, but above 0.7 MeV, heavy ions have an important role in neutron RBE.
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Affiliation(s)
- Azam Zabihi
- Department of Physics, Faculty of Science, Bu-Ali Sina University, Hamedan 651744161, Iran
| | - Sebastien Incerti
- University of Bordeaux, CENBG, UMR No. 5797, 33170 Gradignan, France CNRS, IN2P3, CENBG, UMR No. 5797, 33170 Gradignan, France
| | - Ziad Francis
- Department of Physics, Faculty of Sciences, Université Saint Joseph, 2020 1104 Beirut, Lebanon
| | - Ghasem Forozani
- Department of Physics, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran
| | - Farid Semsarha
- Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran, Iran
| | - Amir Moslehi
- Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran, Iran
| | - Peiman Rezaeian
- Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran, Iran
| | - Mario A Bernal
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo, Brazil
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10
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Baiocco G, Barbieri S, Babini G, Morini J, Friedland W, Kundrát P, Schmitt E, Puchalska M, Giesen U, Nolte R, Ottolenghi A. AT THE PHYSICS-BIOLOGY INTERFACE: THE NEUTRON AFFAIR. RADIATION PROTECTION DOSIMETRY 2018; 180:278-281. [PMID: 29069437 DOI: 10.1093/rpd/ncx222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present predictions of neutron relative biological effectiveness (RBE) for cell irradiations with neutron beams at PTB-Braunschweig. A neutron RBE model is adopted to evaluate initial DNA damage induction given the neutron-induced charged particle field. RBE values are predicted for cell exposures to quasi-monoenergetic beams (0.56 MeV, 1.2 MeV) and to a broad energy distribution neutron field with dose-averaged energy of 5.75 MeV. Results are compared to what obtained with our RBE predictions for neutrons at similar energies, when a 30-cm sphere is irradiated in an isotropic neutron field. RBE values for experimental conditions are higher for the lowest neutron energies, because, as expected, target geometry determines the weight of the low-effectiveness photon component of the neutron dose. These results highlight the importance of characterizing neutron fields in terms of physical interactions, to fully understand neutron-induced biological effects, contributing to risk estimation and to the improvement of radiation protection standards.
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Affiliation(s)
- G Baiocco
- Department of Physics, University of Pavia, Pavia, Italy
| | - S Barbieri
- Department of Physics, University of Pavia, Pavia, Italy
| | - G Babini
- Department of Physics, University of Pavia, Pavia, Italy
| | - J Morini
- Department of Physics, University of Pavia, Pavia, Italy
| | - W Friedland
- Institute of Radiation Protection, Helmholtz Zentrum Mu¨nchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - P Kundrát
- Institute of Radiation Protection, Helmholtz Zentrum Mu¨nchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - E Schmitt
- Institute of Radiation Protection, Helmholtz Zentrum Mu¨nchen, German Research Center for Environmental Health, Neuherberg, Germany
| | | | - U Giesen
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | - R Nolte
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | - A Ottolenghi
- Department of Physics, University of Pavia, Pavia, Italy
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11
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Imaoka T, Nishimura M, Daino K, Hosoki A, Takabatake M, Kokubo T, Doi K, Showler K, Nishimura Y, Moriyama H, Morioka T, Shimada Y, Kakinuma S. Age Modifies the Effect of 2-MeV Fast Neutrons on Rat Mammary Carcinogenesis. Radiat Res 2017; 188:419-425. [DOI: 10.1667/rr14829.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Tatsuhiko Imaoka
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Mayumi Nishimura
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Kazuhiro Daino
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Ayaka Hosoki
- Radiation Effect Accumulation and Prevention Project, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
| | - Masaru Takabatake
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Toshiaki Kokubo
- Department of Engineering and Safety, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Kazutaka Doi
- Center for Radiation Protection Knowledge, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Kaye Showler
- Radiobiology for Children's Health Program, NIRS, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
| | - Yukiko Nishimura
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Hitomi Moriyama
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Takamitsu Morioka
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | | | - Shizuko Kakinuma
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
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12
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Baiocco G, Barbieri S, Babini G, Morini J, Alloni D, Friedland W, Kundrát P, Schmitt E, Puchalska M, Sihver L, Ottolenghi A. The origin of neutron biological effectiveness as a function of energy. Sci Rep 2016; 6:34033. [PMID: 27654349 PMCID: PMC5032018 DOI: 10.1038/srep34033] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 09/05/2016] [Indexed: 12/22/2022] Open
Abstract
The understanding of the impact of radiation quality in early and late responses of biological targets to ionizing radiation exposure necessarily grounds on the results of mechanistic studies starting from physical interactions. This is particularly true when, already at the physical stage, the radiation field is mixed, as it is the case for neutron exposure. Neutron Relative Biological Effectiveness (RBE) is energy dependent, maximal for energies ~1 MeV, varying significantly among different experiments. The aim of this work is to shed light on neutron biological effectiveness as a function of field characteristics, with a comprehensive modeling approach: this brings together transport calculations of neutrons through matter (with the code PHITS) and the predictive power of the biophysical track structure code PARTRAC in terms of DNA damage evaluation. Two different energy dependent neutron RBE models are proposed: the first is phenomenological and based only on the characterization of linear energy transfer on a microscopic scale; the second is purely ab-initio and based on the induction of complex DNA damage. Results for the two models are compared and found in good qualitative agreement with current standards for radiation protection factors, which are agreed upon on the basis of RBE data.
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Affiliation(s)
- G. Baiocco
- Department of Physics, University of Pavia, Pavia, Italy
| | - S. Barbieri
- Department of Physics, University of Pavia, Pavia, Italy
| | - G. Babini
- Department of Physics, University of Pavia, Pavia, Italy
| | - J. Morini
- Department of Physics, University of Pavia, Pavia, Italy
| | - D. Alloni
- INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy
- LENA, Laboratory of Applied Nuclear Energy, University of Pavia, Pavia, Italy
| | - W. Friedland
- Institute of Radiation Protection, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
| | - P. Kundrát
- Institute of Radiation Protection, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
| | - E. Schmitt
- Institute of Radiation Protection, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
| | | | - L. Sihver
- Technische Universität Wien, Wien, Austria
| | - A. Ottolenghi
- Department of Physics, University of Pavia, Pavia, Italy
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Schneider U, Hälg RA, Lomax T. Neutrons in active proton therapy: Parameterization of dose and dose equivalent. Z Med Phys 2016; 27:113-123. [PMID: 27524678 DOI: 10.1016/j.zemedi.2016.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 07/11/2016] [Accepted: 07/11/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. METHODS The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. RESULTS The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160MeV or 177MeV instead of 138MeV. For the neutron dose equivalent the increase is 8% and 57%. CONCLUSIONS The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy.
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Affiliation(s)
- Uwe Schneider
- Department of Physics, Science Faculty, University of Zurich, Zurich, Switzerland; Radiotherapy Hirslanden AG, Rain 34, Aarau, Switzerland.
| | - Roger A Hälg
- Department of Physics, Science Faculty, University of Zurich, Zurich, Switzerland; Radiotherapy Hirslanden AG, Rain 34, Aarau, Switzerland
| | - Tony Lomax
- Center for Proton Therapy, Paul Scherrer Institut, Villigen-PSI, Switzerland
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14
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Schneider U, Hälg RA, Baiocco G, Lomax T. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE. Phys Med Biol 2016; 61:6231-42. [DOI: 10.1088/0031-9155/61/16/6231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Kron T, Lehmann J, Greer PB. Dosimetry of ionising radiation in modern radiation oncology. Phys Med Biol 2016; 61:R167-205. [DOI: 10.1088/0031-9155/61/14/r167] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Schneider U, Hälg R. The Impact of Neutrons in Clinical Proton Therapy. Front Oncol 2015; 5:235. [PMID: 26557501 PMCID: PMC4617104 DOI: 10.3389/fonc.2015.00235] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/06/2015] [Indexed: 11/13/2022] Open
Abstract
In proton therapy, high-energy proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long-term health of cancer patients. Due to the high biological effectiveness of neutrons with regard to cancer induction, small neutron doses can be important. Published comparisons of neutron dose measurements and the corresponding estimates of cancer risk between different treatment modalities differ over orders of magnitude. In this report, the controversy about the impact of the neutron dose in proton therapy is critically discussed and viewed in the light of new epidemiological studies. In summary, the impact of neutron dose on cancer risk can be determined correctly only if the dose distributions are carefully measured or computed. It is important to include not only the neutron component into comparisons but also the complete deposition of energy as precisely as possible. Cancer risk comparisons between different radiation qualities, treatment machines, and techniques have to be performed under similar conditions. It seems that in the past, the uncertainty in the models which lead from dose to risk were overestimated when compared with erroneous dose comparisons. Current risk models used with carefully obtained dose distributions predict a second cancer risk reduction for active protons vs. photons and a more or less constant risk of passive protons vs. photons. Those findings are in general agreement with newly obtained epidemiologically results.
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Affiliation(s)
- Uwe Schneider
- Institute of Physics, Science Faculty, University of Zürich, Zürich, Switzerland
- Radiotherapy Hirslanden, Zürich, Switzerland
| | - Roger Hälg
- Institute of Physics, Science Faculty, University of Zürich, Zürich, Switzerland
- Radiotherapy Hirslanden, Zürich, Switzerland
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Baiocco G, Alloni D, Babini G, Mariotti L, Ottolenghi A. Reaction mechanism interplay in determining the biological effectiveness of neutrons as a function of energy. RADIATION PROTECTION DOSIMETRY 2015; 166:316-319. [PMID: 25848097 DOI: 10.1093/rpd/ncv134] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Neutron relative biological effectiveness (RBE) is found to be energy dependent, being maximal for energies ∼1 MeV. This is reflected in the choice of radiation weighting factors wR for radiation protection purposes. In order to trace back the physical origin of this behaviour, a detailed study of energy deposition processes with their full dependences is necessary. In this work, the Monte Carlo transport code PHITS was used to characterise main secondary products responsible for energy deposition in a 'human-sized' soft tissue spherical phantom, irradiated by monoenergetic neutrons with energies around the maximal RBE/wR. Thereafter, results on the microdosimetric characterisation of secondary protons were used as an input to track structure calculations performed with PARTRAC, thus evaluating the corresponding DNA damage induction. Within the proposed simplified approach, evidence is suggested for a relevant role of secondary protons in inducing the maximal biological effectiveness for 1 MeV neutrons.
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Affiliation(s)
- G Baiocco
- Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy
| | - D Alloni
- Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy LENA, Laboratory of Applied Nuclear Energy, University of Pavia, Pavia, Italy
| | - G Babini
- Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy
| | - L Mariotti
- Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy Department of Oncology, Gray Institute, University of Oxford, Old Road Campus, Oxford OX3 7DQ, UK
| | - A Ottolenghi
- Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy
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