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Gardner LL, O'Connor JD, McMahon SJ. Benchmarking proton RBE models. Phys Med Biol 2024; 69:085022. [PMID: 38471187 DOI: 10.1088/1361-6560/ad3329] [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: 10/03/2023] [Accepted: 03/12/2024] [Indexed: 03/14/2024]
Abstract
Objective.To biologically optimise proton therapy, models which can accurately predict variations in proton relative biological effectiveness (RBE) are essential. Current phenomenological models show large disagreements in RBE predictions, due to different model assumptions and differences in the data to which they were fit. In this work, thirteen RBE models were benchmarked against a comprehensive proton RBE dataset to evaluate predictions when all models are fit using the same data and fitting techniques, and to assess the statistical robustness of the models.Approach.Model performance was initially evaluated by fitting to the full dataset, and then a cross-validation approach was applied to assess model generalisability and robustness. The impact of weighting the fit and the choice of biological endpoint (either single or multiple survival levels) was also evaluated.Main results.Fitting the models to a common dataset reduced differences between their predictions, however significant disagreements remained due to different underlying assumptions. All models performed poorly under cross-validation in the weighted fits, suggesting that some uncertainties on the experimental data were significantly underestimated, resulting in over-fitting and poor performance on unseen data. The simplest model, which depends linearly on the LET but has no tissue or dose dependence, performed best for a single survival level. However, when fitting to multiple survival levels simultaneously, more complex models with tissue dependence performed better. All models had significant residual uncertainty in their predictions compared to experimental data.Significance.This analysis highlights that poor quality of error estimation on the dose response parameters introduces substantial uncertainty in model fitting. The significant residual error present in all approaches illustrates the challenges inherent in fitting to large, heterogeneous datasets and the importance of robust statistical validation of RBE models.
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Affiliation(s)
- Lydia L Gardner
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
| | - John D O'Connor
- School of Engineering, Ulster University, Belfast, United Kingdom
| | - Stephen J McMahon
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
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2
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Chattaraj A, Selvam TP. Calculation of biological effectiveness of SOBP proton beams: a TOPAS Monte Carlo study. Biomed Phys Eng Express 2024; 10:035004. [PMID: 38377599 DOI: 10.1088/2057-1976/ad2b02] [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: 11/01/2023] [Accepted: 02/20/2024] [Indexed: 02/22/2024]
Abstract
Objective.This study aims to investigate the biological effectiveness of Spread-Out Bragg-Peak (SOBP) proton beams with initial kinetic energies 50-250 MeV at different depths in water using TOPAS Monte Carlo code.Approach.The study modelled SOBP proton beams using TOPAS time feature. Various LET-based models and Repair-Misrepair-Fixation model were employed to calculate Relative Biological Effectiveness (RBE) for V79 cell lines at different on-axis depths based on TOPAS. Microdosimetric Kinetic Model and biological weighting function-based models, which utilize microdosimetric distributions, were also used to estimate the RBE. A phase-space-based method was adopted for calculating microdosimetric distributions.Main results.The trend of variation of RBE with depth is similar in all the RBE models, but the absolute RBE values vary based on the calculation models. RBE sharply increases at the distal edge of SOBP proton beams. In the entrance region of all the proton beams, RBE values at 4 Gy i.e. RBE(4 Gy) resulting from different models are in the range of 1.04-1.07, comparable to clinically used generic RBE of 1.1. Moving from the proximal to distal end of the SOBP, RBE(4 Gy) is in the range of 1.15-1.33, 1.13-1.21, 1.11-1.17, 1.13-1.18 and 1.17-1.21, respectively for 50, 100, 150, 200 and 250 MeV SOBP beams, whereas at the distal dose fall-off region, these values are 1.68, 1.53, 1.44, 1.42 and 1.40, respectively.Significance.The study emphasises application of depth-, dose- and energy- dependent RBE values in clinical application of proton beams.
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Affiliation(s)
- Arghya Chattaraj
- Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai-400 085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai-400 094, India
| | - T Palani Selvam
- Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai-400 085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai-400 094, India
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3
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Overgaard CB, Reaz F, Sitarz M, Poulsen P, Overgaard J, Bassler N, Grau C, Sørensen BS. An experimental setup for proton irradiation of a murine leg model for radiobiological studies. Acta Oncol 2023; 62:1566-1573. [PMID: 37603112 DOI: 10.1080/0284186x.2023.2246641] [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: 06/14/2023] [Accepted: 08/03/2023] [Indexed: 08/22/2023]
Abstract
BACKGROUND The purpose of this study was to introduce an experimental radiobiological setup used for in vivo irradiation of a mouse leg target in multiple positions along a proton beam path to investigate normal tissue- and tumor models with varying linear energy transfer (LET). We describe the dosimetric characterizations and an acute- and late-effect assay for normal tissue damage. METHODS The experimental setup consists of a water phantom that allows the right hind leg of three to five mice to be irradiated at the same time. Absolute dosimetry using a thimble (Semiflex) and a plane parallel (Advanced Markus) ionization chamber and Monte Carlo simulations using Geant4 and SHIELD-HIT12A were applied for dosimetric validation of positioning along the spread-out Bragg peak (SOBP) and at the distal edge and dose fall-off. The mice were irradiated in the center of the SOBP delivered by a pencil beam scanning system. The SOBP was 2.8 cm wide, centered at 6.9 cm depth, with planned physical single doses from 22 to 46 Gy. The biological endpoint was acute skin damage and radiation-induced late damage (RILD) assessed in the mouse leg. RESULTS The dose-response curves illustrate the percentage of mice exhibiting acute skin damage, and at a later point, RILD as a function of physical doses (Gy). Each dose-response curve represents a specific severity score of each assay, demonstrating a higher ED50 (50% responders) as the score increases. Moreover, the results reveal the reversible nature of acute skin damage as a function of time and the irreversible nature of RILD as time progresses. CONCLUSIONS We want to encourage researchers to report all experimental details of their radiobiological setups, including experimental protocols and model descriptions, to facilitate transparency and reproducibility. Based on this study, more experiments are being performed to explore all possibilities this radiobiological experimental setup permits.
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Affiliation(s)
- Cathrine Bang Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Fardous Reaz
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
| | - Mateusz Sitarz
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
| | - Per Poulsen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
| | - Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Niels Bassler
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
| | - Cai Grau
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
| | - Brita Singers Sørensen
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
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4
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Sebastián SM, Alejandro C, Ignacio E, Sophia G, Pía VM, Andrea R. Monte Carlo simulations of cell survival in proton SOBP. Phys Med Biol 2023; 68:195024. [PMID: 37673077 DOI: 10.1088/1361-6560/acf752] [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: 06/28/2023] [Accepted: 09/06/2023] [Indexed: 09/08/2023]
Abstract
Objective. The objective of this study is to develop a multi-scale modeling approach that accurately predicts radiation-induced DNA damage and survival fraction in specific cell lines.Approach. A Monte Carlo based simulation framework was employed to make the predictions. The FLUKA Monte Carlo code was utilized to estimate absorbed doses and fluence energy spectra, which were then used in the Monte Carlo Damage Simulation code to compute DNA damage yields in Chinese hamster V79 cell lines. The outputs were converted into cell survival fractions using a previously published theoretical model. To reduce the uncertainties of the predictions, new values for the parameters of the theoretical model were computed, expanding the database of experimental points considered in the previous estimation. Simulated results were validated against experimental data, confirming the applicability of the framework for proton beams up to 230 MeV. Additionally, the impact of secondary particles on cell survival was estimated.Main results. The simulated survival fraction versus depth in a glycerol phantom is reported for eighteen different configurations. Two proton spread out Bragg peaks at several doses were simulated and compared with experimental data. In all cases, the simulations follow the experimental trends, demonstrating the accuracy of the predictions up to 230 MeV.Significance. This study holds significant importance as it contributes to the advancement of models for predicting biological responses to radiation, ultimately contributing to more effective cancer treatment in proton therapy.
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Affiliation(s)
| | - Carabe Alejandro
- Hampton University Proton Therapy Institute, 40 Enterprise Pkwy Hampton, VA 2366, United States of America
| | - Espinoza Ignacio
- Instituto de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
| | - Galvez Sophia
- Instituto de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
| | - Valenzuela María Pía
- Instituto de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
| | - Russomando Andrea
- Instituto de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
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5
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Poon DMC, Wu S, Ho L, Cheung KY, Yu B. Proton Therapy for Prostate Cancer: Challenges and Opportunities. Cancers (Basel) 2022; 14:cancers14040925. [PMID: 35205673 PMCID: PMC8870339 DOI: 10.3390/cancers14040925] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 01/02/2023] Open
Abstract
Simple Summary Reported clinical outcomes of proton therapy (PT) for localized prostate cancer are similar to photon-based external beam radiotherapy. Apparently, the dosimetric advantages of PT have yet to be translated to clinical benefits. The suboptimal clinical outcomes of PT might be attributable to inadequate dose prescription, as indicated by the ASCENDE-RT trial. Moreover, uncertainties involved in the treatment planning and delivery processes, as well as technological limitations in PT treatment systems, may lead to discrepancies between planned doses and actual doses delivered to patients. In this article, we reviewed the current status of PT for prostate cancer and discussed different clinical implementations that could potentially improve the clinical outcome of PT for prostate cancer. Various technological advancements under which uncertainties in dose calculations can be minimized, including MRI-guided PT, dual-energy photon-counting CT and high-resolution Monte Carlo-based treatment planning systems, are highlighted. Abstract The dosimetric advantages of proton therapy (PT) treatment plans are demonstrably superior to photon-based external beam radiotherapy (EBRT) for localized prostate cancer, but the reported clinical outcomes are similar. This may be due to inadequate dose prescription, especially in high-risk disease, as indicated by the ASCENDE-RT trial. Alternatively, the lack of clinical benefits with PT may be attributable to improper dose delivery, mainly due to geometric and dosimetric uncertainties during treatment planning, as well as delivery procedures that compromise the dose conformity of treatments. Advanced high-precision PT technologies, and treatment planning and beam delivery techniques are being developed to address these uncertainties. For instance, external magnetic resonance imaging (MRI)-guided patient setup rooms are being developed to improve the accuracy of patient positioning for treatment. In-room MRI-guided patient positioning systems are also being investigated to improve the geometric accuracy of PT. Soon, high-dose rate beam delivery systems will shorten beam delivery time to within one breath hold, minimizing the effects of organ motion and patient movements. Dual-energy photon-counting computed tomography and high-resolution Monte Carlo-based treatment planning systems are available to minimize uncertainties in dose planning calculations. Advanced in-room treatment verification tools such as prompt gamma detector systems will be used to verify the depth of PT. Clinical implementation of these new technologies is expected to improve the accuracy and dose conformity of PT in the treatment of localized prostate cancers, and lead to better clinical outcomes. Improvement in dose conformity may also facilitate dose escalation, improving local control and implementation of hypofractionation treatment schemes to improve patient throughput and make PT more cost effective.
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Affiliation(s)
- Darren M. C. Poon
- Comprehensive Oncology Centre, Hong Kong Sanatorium & Hospital, Hong Kong 999077, China;
| | - Stephen Wu
- Medical Physics Department, Hong Kong Sanatorium & Hospital, Hong Kong 999077, China; (L.H.); (K.Y.C.); (B.Y.)
- Correspondence: ; Tel.: +852-29171413
| | - Leon Ho
- Medical Physics Department, Hong Kong Sanatorium & Hospital, Hong Kong 999077, China; (L.H.); (K.Y.C.); (B.Y.)
| | - Kin Yin Cheung
- Medical Physics Department, Hong Kong Sanatorium & Hospital, Hong Kong 999077, China; (L.H.); (K.Y.C.); (B.Y.)
| | - Ben Yu
- Medical Physics Department, Hong Kong Sanatorium & Hospital, Hong Kong 999077, China; (L.H.); (K.Y.C.); (B.Y.)
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6
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Rucinski A, Biernacka A, Schulte R. Applications of nanodosimetry in particle therapy planning and beyond. Phys Med Biol 2021; 66. [PMID: 34731854 DOI: 10.1088/1361-6560/ac35f1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/03/2021] [Indexed: 12/28/2022]
Abstract
This topical review summarizes underlying concepts of nanodosimetry. It describes the development and current status of nanodosimetric detector technology. It also gives an overview of Monte Carlo track structure simulations that can provide nanodosimetric parameters for treatment planning of proton and ion therapy. Classical and modern radiobiological assays that can be used to demonstrate the relationship between the frequency and complexity of DNA lesion clusters and nanodosimetric parameters are reviewed. At the end of the review, existing approaches of treatment planning based on relative biological effectiveness (RBE) models or dose-averaged linear energy transfer are contrasted with an RBE-independent approach based on nandosimetric parameters. Beyond treatment planning, nanodosimetry is also expected to have applications and give new insights into radiation protection dosimetry.
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Affiliation(s)
| | - Anna Biernacka
- University of Gdansk, Intercollegiate Faculty of Biotechnology of University of Gdańsk and Medical University of Gdansk, 80-307 Gdansk, Poland
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7
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Almhagen E, Traneus E, Ahnesjö A. Handling of beam spectra in training and application of proton RBE models. Phys Med Biol 2021; 66. [PMID: 34464939 DOI: 10.1088/1361-6560/ac226a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/31/2021] [Indexed: 11/11/2022]
Abstract
Published data from cell survival experiments are frequently used as training data for models of proton relative biological effectiveness (RBE). The publications rarely provide full information about the primary particle spectrum of the used beam, or its content of heavy secondary particles. The purpose of this paper is to assess to what extent heavy secondary particles may have been present in published cell survival experiments, and to investigate the impact of non-primary protons for RBE calculations in treatment planning. We used the Monte Carlo code Geant4 to calculate the occurrence of non-primary protons and heavier secondary particles for clinical protons beams in water for four incident energies in the [100, 250] MeV interval. We used the resulting spectra together with a conservative RBE parameterization and an RBE model to map both the rise of RBE at the beam entry surface due to heavy secondary particle buildup, and the difference in estimated RBE if non-primary protons are included or not in the beam quality metric. If included, non-primary protons cause a difference of 2% of the RBE in the plateau region of an spread out Bragg peak and 1% in the Bragg peak. Including non-primary protons specifically for RBE calculations will consequently have a negligible impact and can be ignored. A buildup distance in water of one millimeter was sufficient to reach an equilibrium state of RBE for the four incident energies selected. For the investigated experimental data, 83 out of the 86 data points were found to have been determined with at least that amount of buildup material. Hence, RBE model training data should be interpreted to include the contribution of heavy secondaries.
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Affiliation(s)
- Erik Almhagen
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Akademiska Sjukhuset, Uppsala, Sweden.,The Skandion Clinic, Uppsala, Sweden
| | | | - Anders Ahnesjö
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Akademiska Sjukhuset, Uppsala, Sweden
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8
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Sørensen BS, Pawelke J, Bauer J, Burnet NG, Dasu A, Høyer M, Karger CP, Krause M, Schwarz M, Underwood TSA, Wagenaar D, Whitfield GA, Lühr A. Does the uncertainty in relative biological effectiveness affect patient treatment in proton therapy? Radiother Oncol 2021; 163:177-184. [PMID: 34480959 DOI: 10.1016/j.radonc.2021.08.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 08/09/2021] [Accepted: 08/22/2021] [Indexed: 10/20/2022]
Abstract
Clinical treatment with protons uses the concept of relative biological effectiveness (RBE) to convert the absorbed dose into an RBE-weighted dose that equals the dose for radiotherapy with photons causing the same biological effect. Currently, in proton therapy a constant RBE of 1.1 is generically used. However, empirical data indicate that the RBE is not constant, but increases at the distal edge of the proton beam. This increase in RBE is of concern, as the clinical impact is still unresolved, and clinical studies demonstrating a clinical effect of an increased RBE are emerging. Within the European Particle Therapy Network (EPTN) work package 6 on radiobiology and RBE, a workshop was held in February 2020 in Manchester with one day of discussion dedicated to the impact of proton RBE in a clinical context. Current data on RBE effects, patient outcome and modelling from experimental as well as clinical studies were presented and discussed. Furthermore, representatives from European clinical proton therapy centres, who were involved in patient treatment, laid out their current clinical practice on how to consider the risk of a variable RBE in their centres. In line with the workshop, this work considers the actual impact of RBE issues on patient care in proton therapy by reviewing preclinical data on the relation between linear energy transfer (LET) and RBE, current clinical data sets on RBE effects in patients, and applied clinical strategies to manage RBE uncertainties. A better understanding of the variability in RBE would allow development of proton treatments which are safer and more effective.
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Affiliation(s)
- Brita S Sørensen
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark; Experimental Clinical Oncology - Department of Oncology, Aarhus University Hospital, Aarhus, Denmark.
| | - Jörg Pawelke
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Julia Bauer
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | | | - Alexandru Dasu
- The Skandion Clinic, Uppsala, Sweden; Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Morten Høyer
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Christian P Karger
- Dept. of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Heidelberg Institute for Radiation Oncology (HIRO) and National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Mechthild Krause
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Institute of Radiooncology-OncoRay, Dresden, Germany; German Cancer Consortium Dresden and German Cancer Research Center Heidelberg, Germany; Dept. of Radiation Oncology, University Hospital and Faculty of Medicine C.G. Carus, Dresden, Germany; National Center for Tumor Diseases Dresden, German Cancer Research Center Heidelberg, University Hospital and Faculty of Medicine C.G. Carus Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany
| | - Marco Schwarz
- Protontherapy Department -Trento Hospital, and TIFPA-INFN, Trento, Italy
| | - Tracy S A Underwood
- Division of Cancer Sciences, School of Medical Sciences, The University of Manchester, UK
| | - Dirk Wagenaar
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Gillian A Whitfield
- The Christie NHS Foundation Trust, Manchester, UK; University of Manchester, UK
| | - Armin Lühr
- Department of Physics, TU Dortmund University, Dortmund, Germany
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9
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Parisi A, Sato T, Matsuya Y, Kase Y, Magrin G, Verona C, Tran L, Rosenfeld A, Bianchi A, Olko P, Struelens L, Vanhavere F. Development of a new microdosimetric biological weighting function for the RBE 10 assessment in case of the V79 cell line exposed to ions from 1H to 238U. Phys Med Biol 2020; 65:235010. [PMID: 33274727 DOI: 10.1088/1361-6560/abbf96] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An improved biological weighting function (IBWF) is proposed to phenomenologically relate microdosimetric lineal energy probability density distributions with the relative biological effectiveness (RBE) for the in vitro clonogenic cell survival (surviving fraction = 10%) of the most commonly used mammalian cell line, i.e. the Chinese hamster lung fibroblasts (V79). The IBWF, intended as a simple and robust tool for a fast RBE assessment to compare different exposure conditions in particle therapy beams, was determined through an iterative global-fitting process aimed to minimize the average relative deviation between RBE calculations and literature in vitro data in case of exposure to various types of ions from 1H to 238U. By using a single particle- and energy- independent function, it was possible to establish an univocal correlation between lineal energy and clonogenic cell survival for particles spanning over an unrestricted linear energy transfer range of almost five orders of magnitude (0.2 keV µm-1 to 15 000 keV µm-1 in liquid water). The average deviation between IBWF-derived RBE values and the published in vitro data was ∼14%. The IBWF results were also compared with corresponding calculations (in vitro RBE10 for the V79 cell line) performed using the modified microdosimetric kinetic model (modified MKM). Furthermore, RBE values computed with the reference biological weighting function (BWF) for the in vivo early intestine tolerance in mice were included for comparison and to further explore potential correlations between the BWF results and the in vitro RBE as reported in previous studies. The results suggest that the modified MKM possess limitations in reproducing the experimental in vitro RBE10 for the V79 cell line in case of ions heavier than 20Ne. Furthermore, due to the different modelled endpoint, marked deviations were found between the RBE values assessed using the reference BWF and the IBWF for ions heavier than 2H. Finally, the IBWF was unchangingly applied to calculate RBE values by processing lineal energy density distributions experimentally measured with eight different microdosimeters in 19 1H and 12C beams at ten different facilities (eight clinical and two research ones). Despite the differences between the detectors, irradiation facilities, beam profiles (pristine or spread out Bragg peak), maximum beam energy, beam delivery (passive or active scanning), energy degradation system (water, PMMA, polyamide or low-density polyethylene), the obtained IBWF-based RBE trends were found to be in good agreement with the corresponding ones in case of computer-simulated microdosimetric spectra (average relative deviation equal to 0.8% and 5.7% for 1H and 12C ions respectively).
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10
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Bertolet A, Grilj V, Guardiola C, Harken AD, Cortés-Giraldo MA, Baratto-Roldán A, Carabe A. Experimental validation of an analytical microdosimetric model based on Geant4-DNA simulations by using a silicon-based microdosimeter. Radiat Phys Chem Oxf Engl 1993 2020; 176:109060. [PMID: 33100611 PMCID: PMC7583143 DOI: 10.1016/j.radphyschem.2020.109060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PURPOSE To study the agreement between proton microdosimetric distributions measured with a silicon-based cylindrical microdosimeter and a previously published analytical microdosimetric model based on Geant4-DNA in-water Monte Carlo simulations for low energy proton beams. METHODS AND MATERIAL Distributions for lineal energy (y) are measured for four proton monoenergetic beams with nominal energies from 2.0 MeV to 4.5 MeV, with a tissue equivalent proportional counter (TEPC) and a silicon-based microdosimeter. The actual energy for protons traversing the silicon-based microdosimeter is simulated with SRIM. Monoenergetic beams with these energies are simulated with Geant4-DNA code by simulating a water cylinder site of dimensions equal to those of the microdosimeter. The microdosimeter response is calibrated by using the distribution peaks obtained from the TEPC. Analytical calculations fory ¯ F andy ¯ D using our methodology based on spherical sites are also performed choosing the equivalent sphere to be checked against experimental results. RESULTS Distributions for y at silicon are converted into tissue equivalent and compared to the Geant4-DNA simulated, yielding maximum deviations of 1.03% fory ¯ F and 1.17% fory ¯ D . Our analytical method generates maximum deviations of 1.29% and 3.33%, respectively, with respect to experimental results. CONCLUSION Simulations in Geant4-DNA with ideal cylindrical sites in liquid water produce similar results to the measurements in an actual silicon-based cylindrical microdosimeter properly calibrated. The found agreement suggests the possibility to experimentally verify the calculated clinicaly ¯ D with our analytical method.
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Affiliation(s)
- A Bertolet
- Department of Radiation Oncology, Hospital of The University of Pennsylvania, Philadelphia, PA, USA
- Department of Atomic, Molecular and Nuclear Physics, Universidad de Sevilla, Seville, Spain
| | - V Grilj
- Radiological Research Accelerator Facility, Columbia University, Irvington, NY, USA
| | - C Guardiola
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France; Université de Paris, IJCLab, 91405 Orsay France
| | - A D Harken
- Radiological Research Accelerator Facility, Columbia University, Irvington, NY, USA
| | - M A Cortés-Giraldo
- Department of Atomic, Molecular and Nuclear Physics, Universidad de Sevilla, Seville, Spain
| | - A Baratto-Roldán
- Department of Atomic, Molecular and Nuclear Physics, Universidad de Sevilla, Seville, Spain
| | - A Carabe
- Department of Radiation Oncology, Hospital of The University of Pennsylvania, Philadelphia, PA, USA
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11
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Deycmar S, Faccin E, Kazimova T, Knobel PA, Telarovic I, Tschanz F, Waller V, Winkler R, Yong C, Zingariello D, Pruschy M. The relative biological effectiveness of proton irradiation in dependence of DNA damage repair. Br J Radiol 2019; 93:20190494. [PMID: 31687835 DOI: 10.1259/bjr.20190494] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Clinical parameters and empirical evidence are the primary determinants for current treatment planning in radiation oncology. Personalized medicine in radiation oncology is only at the very beginning to take the genetic background of a tumor entity into consideration to define an individual treatment regimen, the total dose or the combination with a specific anticancer agent. Likewise, stratification of patients towards proton radiotherapy is linked to its physical advantageous energy deposition at the tumor site with minimal healthy tissue being co-irradiated distal to the target volume. Hence, the fact that photon and proton irradiation also induce different qualities of DNA damages, which require differential DNA damage repair mechanisms has been completely neglected so far. These subtle differences could be efficiently exploited in a personalized treatment approach and could be integrated into personalized treatment planning. A differential requirement of the two major DNA double-strand break repair pathways, homologous recombination and non-homologous end joining, was recently identified in response to proton and photon irradiation, respectively, and subsequently influence the mode of ionizing radiation-induced cell death and susceptibility of tumor cells with defects in DNA repair machineries to either quality of ionizing radiation.This review focuses on the differential DNA-damage responses and subsequent biological processes induced by photon and proton irradiation in dependence of the genetic background and discusses their impact on the unicellular level and in the tumor microenvironment and their implications for combined treatment modalities.
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Affiliation(s)
- Simon Deycmar
- Laboratory for Applied Radiobiology Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
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12
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Sørensen BS. Commentary: RBE in proton therapy - where is the experimental in vivo data? Acta Oncol 2019; 58:1337-1339. [PMID: 31578911 DOI: 10.1080/0284186x.2019.1669819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Brita Singers Sørensen
- Department of Experimental Clinical Oncology and Danish Center for Particle Therapy, DCPT, Aarhus University Hospital, Aarhus, Denmark
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Li X, Zhang W, Wang X, Chen X, Pan H, Ruan Y, Khaledi N, Wei T, He X, Zhuo W, Shao C, Pan Y, Shi L, Fu S, Wang X. Charged particle radiobiology beamline using tandem accelerator-based MeV protons and carbon ions: a pilot study on the track-end radiation quality, variable biological effectiveness and Bayesian beam dosimetry. Phys Med Biol 2019; 64:165004. [PMID: 31096198 DOI: 10.1088/1361-6560/ab21fa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
For in vitro cell irradiation using tandem accelerator-based MeV protons and carbon ions, by TOPAS simulation, a pilot study of performance evaluation is presented on a collimation beamline for 3 MeV protons and 10 MeV carbon ions from a 2 × 3 MV tandem accelerator. Based on the elements and source parameters, a collimated beam of 2.8 MeV protons or 2.5 MeV carbon ions, with 5.175 mm or 5.166 mm full width tenth maximum (FWTM), respectively, can be delivered to the target cell dish. TOPAS simulations and/or deterministic algorithms present a Bragg curve of linear energy transfer (LET) (10-70 keV μm-1) along a 138 μm range of the proton beam, and a declining LET of the carbon beam (900-100 keV μm-1) within 4 μm range. Based on the biophysical models for relative biological effectiveness (RBE) of protons, TOPAS RBE scorers presents a set of depth-variation curves of the proton RBE (for V79 and DU145 cells), linearly related to the Bragg curve of the proton LET. Based on the microdosimetric-kinetic (MK) theory, in the 4 μm range for a monolayer cell thickness, the mean RBEα (V79 cells) of the carbon ion beam is estimated as 3.612 (late S phase) and 1.737 (G 1/S phase) for the mean LET of 492 keV μm-1. For practical irradiations, a tunable proton RBE can be acquired by changing the thickness of the cell dish. For the low-energy high-fluence (rate) beams, indirect beam measurements are proposed to detect the proton-beam induced scattering/recoil protons from a beam-intercepting Mylar film, and the carbon-beam induced backscattered electrons from a gold-deposited Havar-foil beam window. Statistical dosimetry for the indirect measurement is established, using a Bayesian model based on the preset number of detection counts, by which the mean value of the whole-dish dose can be prescribed and the uncertainty introduced in the survival data can be corrected.
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Affiliation(s)
- Xiang Li
- Institute of Modern Physics, Fudan University, Shanghai 200433, People's Republic of China. Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Fudan University, Shanghai 200433, People's Republic of China. Co-first authors having equal contribution to this work
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Qi Tan H, Yang Calvin Koh W, Kuan Rui Tan L, Hao Phua J, Wei Ang K, Yong Park S, Siang Lew W, Cheow Lei Lee J. Dependence of LET on material and its impact on current RBE model. ACTA ACUST UNITED AC 2019; 64:135022. [DOI: 10.1088/1361-6560/ab1c90] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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15
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Parisi A, Chiriotti S, De Saint-Hubert M, Van Hoey O, Vandevoorde C, Beukes P, de Kock EA, Symons J, Camero JN, Slabbert J, Mégret P, Debrot E, Bolst D, Rosenfeld A, Vanhavere F. A novel methodology to assess linear energy transfer and relative biological effectiveness in proton therapy using pairs of differently doped thermoluminescent detectors. Phys Med Biol 2019; 64:085005. [PMID: 30650402 DOI: 10.1088/1361-6560/aaff20] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A new methodology for assessing linear energy transfer (LET) and relative biological effectiveness (RBE) in proton therapy beams using thermoluminescent detectors is presented. The method is based on the different LET response of two different lithium fluoride thermoluminescent detectors (LiF:Mg,Ti and LiF:Mg,Cu,P) for measuring charged particles. The relative efficiency of the two detector types was predicted using the recently developed Microdosimetric d(z) Model in combination with the Monte Carlo code PHITS. Afterwards, the calculated ratio of the expected response of the two detector types was correlated with the fluence- and dose- mean values of the unrestricted proton LET. Using the obtained proton dose mean LET as input, the RBE was assessed using a phenomenological biophysical model of cell survival. The aforementioned methodology was benchmarked by exposing the detectors at different depths within the spread out Bragg peak (SOBP) of a clinical proton beam at iThemba LABS. The assessed LET values were found to be in good agreement with the results of radiation transport computer simulations performed using the Monte Carlo code GEANT4. Furthermore, the estimated RBE values were compared with the RBE values experimentally determined by performing colony survival measurements with Chinese Hamster Ovary (CHO) cells during the same experimental run. A very good agreement was found between the results of the proposed methodology and the results of the in vitro study.
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Affiliation(s)
- Alessio Parisi
- Belgian Nuclear Research Centre SCK·CEN, Mol, Belgium. University of Mons, Faculty of Engineering, Mons, Belgium. Author to whom any correspondence should be addressed
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Hu M, Jiang L, Cui X, Zhang J, Yu J. Proton beam therapy for cancer in the era of precision medicine. J Hematol Oncol 2018; 11:136. [PMID: 30541578 PMCID: PMC6290507 DOI: 10.1186/s13045-018-0683-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/28/2018] [Indexed: 02/06/2023] Open
Abstract
Precision radiotherapy, which accurately delivers the dose on a tumor and confers little or no irradiation to the surrounding normal tissue and organs, results in maximum tumor control and decreases the toxicity to the utmost extent. Proton beam therapy (PBT) provides superior dose distributions and has a dosimetric advantage over photon beam therapy. Initially, the clinical practice and study of proton beam therapy focused on ocular tumor, skull base, paraspinal tumors (chondrosarcoma and chordoma), and unresectable sarcomas, which responded poorly when treated with photon radiotherapy. Then, it is widely regarded as an ideal mode for reirradiation and pediatrics due to reducing unwanted side effects by lessening the dose to normal tissue. During the past decade, the application of PBT has been rapidly increasing worldwide and gradually expanding for the treatment of various malignancies. However, to date, the role of PBT in clinical settings is still controversial, and there are considerable challenges in its application. We systematically review the latest advances of PBT and the challenges for patient treatment in the era of precision medicine.
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Affiliation(s)
- Man Hu
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
- Departments of Radiation Oncology and Shandong Province Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - Liyang Jiang
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
- Departments of Radiation Oncology and Shandong Province Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - Xiangli Cui
- Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, China
| | - Jianguang Zhang
- Departments of Radiation Oncology, Zibo Wanjie Cancer Hospital, Zibo, Shandong, China
| | - Jinming Yu
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan, China.
- Shandong Academy of Medical Sciences, Jinan, China.
- Departments of Radiation Oncology and Shandong Province Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
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Ray S, Cekanaviciute E, Lima IP, Sørensen BS, Costes SV. Comparing Photon and Charged Particle Therapy Using DNA Damage Biomarkers. Int J Part Ther 2018; 5:15-24. [PMID: 31773017 DOI: 10.14338/ijpt-18-00018.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/05/2018] [Indexed: 11/21/2022] Open
Abstract
Treatment modalities for cancer radiation therapy have become increasingly diversified given the growing number of facilities providing proton and carbon-ion therapy in addition to the more historically accepted photon therapy. An understanding of high-LET radiobiology is critical for optimization of charged particle radiation therapy and potential DNA damage response. In this review, we present a comprehensive summary and comparison of these types of therapy monitored primarily by using DNA damage biomarkers. We focus on their relative profiles of dose distribution and mechanisms of action from the level of nucleic acid to tumor cell death.
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Affiliation(s)
- Shayoni Ray
- USRA/NASA Ames Research Center, Moffett Field, CA, USA
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18
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Ilicic K, Combs SE, Schmid TE. New insights in the relative radiobiological effectiveness of proton irradiation. Radiat Oncol 2018; 13:6. [PMID: 29338744 PMCID: PMC5771069 DOI: 10.1186/s13014-018-0954-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/05/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Proton radiotherapy is a form of charged particle therapy that is preferentially applied for the treatment of tumors positioned near to critical structures due to their physical characteristics, showing an inverted depth-dose profile. The sparing of normal tissue has additional advantages in the treatment of pediatric patients, in whom the risk of secondary cancers and late morbidity is significantly higher. Up to date, a fixed relative biological effectiveness (RBE) of 1.1 is commonly implemented in treatment planning systems with protons in order to correct the physical dose. This value of 1.1 comes from averaging the results of numerous in vitro experiments, mostly conducted in the middle of the spread-out Bragg peak, where RBE is relatively constant. However, the use of a constant RBE value disregards the experimental evidence which clearly demonstrates complex RBE dependency on dose, cell- or tissue type, linear energy transfer and biological endpoints. In recent years, several in vitro studies indicate variations in RBE of protons which translate to an uncertainty in the biological effective dose delivery to the patient. Particularly for regions surrounding the Bragg peak, the more localized pattern of energy deposition leads to more complex DNA lesions. These RBE variations of protons bring the validity of using a constant RBE into question. MAIN BODY This review analyzes how RBE depends on the dose, different biological endpoints and physical properties. Further, this review gives an overview of the new insights based on findings made during the last years investigating the variation of RBE with depth in the spread out Bragg peak and the underlying differences in radiation response on the molecular and cellular levels between proton and photon irradiation. Research groups such as the Klinische Forschergruppe Schwerionentherapie funded by the German Research Foundation (DFG, KFO 214) have included work on this topic and the present manuscript highlights parts of the preclinical work and summarizes the research activities in this context. SHORT CONCLUSION In summary, there is an urgent need for more coordinated in vitro and in vivo experiments that concentrate on a realistic dose range of in clinically relevant tissues like lung or spinal cord.
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Affiliation(s)
- K Ilicic
- Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,Institute of Innovative Radiotherapy, Helmholtz Zentrum München, Neuherberg, Germany
| | - S E Combs
- Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,Institute of Innovative Radiotherapy, Helmholtz Zentrum München, Neuherberg, Germany.,Deutsches Konsortium für Translationale Krebsforschung (DKTK), Partner Site Munich, Munich, Germany
| | - T E Schmid
- Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany. .,Institute of Innovative Radiotherapy, Helmholtz Zentrum München, Neuherberg, Germany.
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19
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Sørensen BS, Bassler N, Nielsen S, Horsman MR, Grzanka L, Spejlborg H, Swakoń J, Olko P, Overgaard J. Relative biological effectiveness (RBE) and distal edge effects of proton radiation on early damage in vivo. Acta Oncol 2017; 56:1387-1391. [PMID: 28830292 DOI: 10.1080/0284186x.2017.1351621] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The aim of the present study was to examine the RBE for early damage in an in vivo mouse model, and the effect of the increased linear energy transfer (LET) towards the distal edge of the spread-out Bragg peak (SOBP). METHOD The lower part of the right hind limb of CDF1 mice was irradiated with single fractions of either 6 MV photons, 240 kV photons or scanning beam protons and graded doses were applied. For the proton irradiation, the leg was either placed in the middle of a 30-mm SOBP, or to assess the effect in different positions, irradiated in 4 mm intervals from the middle of the SOBP to behind the distal dose fall-off. Irradiations were performed with the same dose plan at all positions, corresponding to a dose of 31.25 Gy in the middle of the SOBP. Endpoint of the study was early skin damage of the foot, assessed by a mouse foot skin scoring system. RESULTS The MDD50 values with 95% confidence intervals were 36.1 (34.2-38.1) Gy for protons in the middle of the SOBP for score 3.5. For 6 MV photons, it was 35.9 (34.5-37.5) Gy and 32.6 (30.7-34.7) Gy for 240 kV photons for score 3.5. The corresponding RBE was 1.00 (0.94-1.05), relative to 6 MV photons and 0.9 (0.85-0.97) relative to 240 kV photons. In the mice group positioned at the SOBP distal dose fall-off, 25% of the mice developed early skin damage compared with 0-8% in other groups. LETd,z = 1 was 8.4 keV/μm at the distal dose fall-off and the physical dose delivered was 7% lower than in the central SOBP position, where LETd,z =1 was 3.3 keV/μm. CONCLUSIONS Although there is a need to expand the current study to be able to calculate an exact enhancement ratio, an enhanced biological effect in vivo for early skin damage in the distal edge was demonstrated.
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Affiliation(s)
- Brita Singers Sørensen
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Niels Bassler
- Medical Radiation Physics, Department of Physics, Stockholm University, Stockholm, Sweden
| | - Steffen Nielsen
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Michael R. Horsman
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Leszek Grzanka
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
| | - Harald Spejlborg
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Jan Swakoń
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
| | - Paweł Olko
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
| | - Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
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Takagi M, Demizu Y, Terashima K, Fujii O, Jin D, Niwa Y, Daimon T, Murakami M, Fuwa N, Okimoto T. Long-term outcomes in patients treated with proton therapy for localized prostate cancer. Cancer Med 2017; 6:2234-2243. [PMID: 28879658 PMCID: PMC5633560 DOI: 10.1002/cam4.1159] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 05/19/2017] [Accepted: 07/16/2017] [Indexed: 12/24/2022] Open
Abstract
The aim of this retrospective study was to report long-term clinical outcomes in patients treated with proton therapy (PT) for localized prostate cancer. Between 2001 and 2014, 1375 consecutive patients were treated with PT. Patients were classified into prognostic risk groups based on the National Comprehensive Cancer Network criteria. Freedom from biochemical relapse (FFBR), cancer-specific survival (CSS) and incidence of late gastrointestinal (GI)/genitourinary (GU) toxicities were calculated. Multivariate analysis was performed to identify clinical prognostic factors for FFBR and late toxicities. The median follow-up period was 70 months (range, 4-145 months). In total, 99% of patients received 74 Gy (relative biologic effectiveness [RBE]); 56% of patients received neoadjuvant androgen deprivation therapy. For the low-, intermediate-, high-, and very high-risk groups, 5-year FFBR was 99% (95% confidence intervals [CI], 96-100%), 91% (95% CI, 88-93%), 86% (95% CI, 82-89%), and 66% (95% CI, 53-76%), respectively, and 5-year CSS was 100% (95% CI, 100-100%), 100% (95% CI, 100-100%) , 99% (95% CI, 97-100%), and 95% (95% CI, 94-98%), respectively. Patient age, T classification, Gleason score, prostate-specific antigen, and percentage of positive cores were significant prognostic factors for FFBR. Grade 2 or higher GI and GU toxicities were 3.9% and 2.0%. Patient age was a prognostic factor for both late GI and GU toxicities. This study represents the largest cohort of patients treated with PT for localized prostate cancer, with the longest follow-up to date. Our results demonstrate that the biochemical control of PT is favorable particularly for high- and very high-risk patients with lower late genitourinary toxicity and indicates the necessity of considering patient age in the treatment protocols.
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Affiliation(s)
- Masaru Takagi
- Proton Therapy Center, Sapporo Teishinkai Hospital, Sapporo, Hokkaido, Japan.,Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan
| | - Yusuke Demizu
- Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan
| | - Kazuki Terashima
- Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan
| | - Osamu Fujii
- Department of Radiation Oncology, Hakodate Goryoukaku Hospital, Hakodate, Hokkaido, Japan
| | - Dongcun Jin
- Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan
| | - Yasue Niwa
- Department of Radiology, Uji-Tokushukai Medical Center, Uji, Kyoto, Japan
| | - Takashi Daimon
- Department of Biostatistics, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Masao Murakami
- Center for Radiation Oncology, Dokkyo Medical University, Shimotsuga-gun, Tochigi, Japan
| | - Nobukazu Fuwa
- Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan
| | - Tomoaki Okimoto
- Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan
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Hojo H, Dohmae T, Hotta K, Kohno R, Motegi A, Yagishita A, Makinoshima H, Tsuchihara K, Akimoto T. Difference in the relative biological effectiveness and DNA damage repair processes in response to proton beam therapy according to the positions of the spread out Bragg peak. Radiat Oncol 2017; 12:111. [PMID: 28673358 PMCID: PMC5494883 DOI: 10.1186/s13014-017-0849-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/28/2017] [Indexed: 12/25/2022] Open
Abstract
Background Cellular responses to proton beam irradiation are not yet clearly understood, especially differences in the relative biological effectiveness (RBE) of high-energy proton beams depending on the position on the Spread-Out Bragg Peak (SOBP). Towards this end, we investigated the differences in the biological effect of a high-energy proton beam on the target cells placed at different positions on the SOBP, using two human esophageal cancer cell lines with differing radiosensitivities. Methods Two human esophageal cancer cell lines (OE21, KYSE450) with different radiosensitivities were irradiated with a 235-MeV proton beam at 4 different positions on the SOBP (position #1: At entry; position #2: At the proximal end of the SOBP; position #3: Center of the SOBP; position #4: At the distal end of the SOBP), and the cell survivals were assessed by the clonogenic assay. The RBE10 for each position of the target cell lines on the SOBP was determined based on the results of the cell survival assay conducted after photon beam irradiation. In addition, the number of DNA double-strand breaks was estimated by quantitating the number of phospho-histone H2AX (γH2AX) foci formed in the nuclei by immunofluorescence analysis. Results In regard to differences in the RBE of a proton beam according to the position on the SOBP, the RBE value tended to increase as the position on the SOBP moved distally. Comparison of the residual number of γH2AX foci at the end 24 h after the irradiation revealed, for both cell lines, a higher number of foci in the cells irradiated at the distal end of the SOPB than in those irradiated at the proximal end or center of the SOBP. Conclusions The results of this study demonstrate that the RBE of a high-energy proton beam and the cellular responses, including the DNA damage repair processes, to high-energy proton beam irradiation, differ according to the position on the SOBP, irrespective of the radiosensitivity levels of the cell lines. Electronic supplementary material The online version of this article (doi:10.1186/s13014-017-0849-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hidehiro Hojo
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan.
| | - Takeshi Dohmae
- High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Kenji Hotta
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
| | - Ryosuke Kohno
- Department of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, 1840 Old Spanish Trail, Houston, TX, 77054, USA
| | - Atsushi Motegi
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
| | - Atsushi Yagishita
- Division of Translational Research, EPOC, National Cancer Center, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
| | - Hideki Makinoshima
- Division of Translational Research, EPOC, National Cancer Center, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
| | - Katsuya Tsuchihara
- Division of Translational Research, EPOC, National Cancer Center, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
| | - Tetsuo Akimoto
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
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Relative biological effectiveness in a proton spread-out Bragg peak formed by pencil beam scanning mode. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:359-368. [PMID: 28321635 DOI: 10.1007/s13246-017-0540-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 03/09/2017] [Indexed: 10/19/2022]
Abstract
In recent years, there is an increased interest in using scanning modes in proton therapy, due to the more conformal dose distributions, thanks to the spot-weighted dose delivery. The dose rate in each spot is however much higher than the dose rate when using passive irradiation modes, which could affect the cell response. The purpose of this work was to investigate how the relative biological effectiveness changes along the spread-out Bragg peak created by protons delivered by the pencil beam scanning mode. Cell survival and micronuclei formation were investigated in four positions along the spread-out Bragg peak for various doses. Monte Carlo simulations were used to estimate the dose-averaged linear energy transfer values in the irradiation positions. The cell survival was found to decrease the deeper the sample was placed in the spread-out Bragg peak, which corresponds to the higher linear energy transfer values found using Monte Carlo simulations. The micronuclei frequencies indicate more complex cell injuries at that distal position compared to the proximal part of the spread-out Bragg peak. The relative biological effectiveness determined in this study varies significantly and systematically from 1.1, which is recommended value by the International Commission on Radiation Units, in all the studied positions. In the distal position of spread-out Bragg peak the relative biological effectiveness values were found to be 2.05 ± 0.44, 1.85 ± 0.42, 1.53 ± 0.38 for survival levels 90, 50 and 10%, respectively.
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Bian C, Chen N, Li XL, Zhou XG, Lin H, Jiang LB, Liu WM, Chen Q, Dong J. Surgery Combined with Radiotherapy to Treat Spinal Tumors: A Review of Published Reports. Orthop Surg 2017; 8:97-104. [PMID: 27384717 DOI: 10.1111/os.12230] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 02/07/2016] [Indexed: 12/11/2022] Open
Abstract
Spinal tumors result in high morbidity and a high rate of lower limb paralysis. Both surgical therapy and radiation therapy (RT) are used to treat spinal tumors; however, how best to combine these two therapies to maximize the benefits and minimize the risks is still being debated. It is also difficult to decide the optimal timing, course and dose of RT, especially in pregnant women and children. The aim of this review is to assist surgeons who are dealing with spinal tumors by providing comprehensive information about advanced techniques for administering RT with greater precision and safety, and about the impact of various ways of combining surgery and RT on therapeutic outcomes. We here review published reports about treating spinal tumors with a combination of these two forms of therapy and attempt to draw appropriate conclusions concerning selection of optimal treatment protocols. Our conclusion is that postoperative radiotherapy, especially with high-precision, low-dose and multiple fractions, and brachytherapy are promising therapies to combined with surgery.
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Affiliation(s)
- Chong Bian
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Nong Chen
- Department of Orthopaedic Surgery, Zhongshan Hospital Qingpu Branch, Fudan University, Shanghai, China
| | - Xi-Lei Li
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiao-Gang Zhou
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Hong Lin
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Li-Bo Jiang
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wang-Mi Liu
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qian Chen
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jian Dong
- Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
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Grün R, Friedrich T, Krämer M, Scholz M. Systematics of relative biological effectiveness measurements for proton radiation along the spread out Bragg peak: experimental validation of the local effect model. Phys Med Biol 2017; 62:890-908. [PMID: 28072575 DOI: 10.1088/1361-6560/62/3/890] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purpose of this study is to compare the predictions of the local effect model (LEM) in an extensive analysis to proton relative biological effectiveness (RBE) experiments found in the literature, and demonstrate the capabilities of the model as well as to discuss potential limitations. 19 publications with in vitro experiments and 10 publications with in vivo experiments focusing on proton RBE along the spread out Bragg peak (SOBP) were considered. In total the RBE values of over 100 depth positions were compared to LEM predictions. The treatment planning software TRiP98 was used to reconstruct the proton depth dose profile, and, together with the physical dose distribution, the RBE prediction was conducted based on the LEM. Only parameters from photon dose response curves are used as input for the LEM, and no free parameters are introduced, thus allowing us to demonstrate the predictive power of the LEM for protons. The LEM describes the RBE adequately well within the SOBP region with a relative deviation of typically less than 10% up to 10 keV µm-1. In accordance with previous publications a clear dependence of RBE on the dose-averaged linear energy transfer (LETD) was observed. The RBE in the experiments tends to increase above 1.1 for LETD values above 2 keV µm-1 and above 1.5 for LETD values higher than 10 keV µm-1 (distal part of the SOBP). The dose dependence is most pronounced for doses lower than 3 Gy (RBE). However, both the LEM predictions and experimental data show only a weak dependence of RBE on the tissue type, as characterized by the α/β ratio, which is considered insignificant with regard to the general uncertainties of RBE. The RBE predicted by the LEM shows overall very good agreement with the experimental data within the SOBP region and is in better agreement with the experimental data than the constant RBE of 1.1 that is currently applied in the clinics. All RBE trends deduced from the experiments were also reflected by the LEM predictions, which are purely based on input parameters derived from low-LET photon radiation.
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Affiliation(s)
- Rebecca Grün
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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25
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Maeda K, Yasui H, Matsuura T, Yamamori T, Suzuki M, Nagane M, Nam JM, Inanami O, Shirato H. Evaluation of the relative biological effectiveness of spot-scanning proton irradiation in vitro. JOURNAL OF RADIATION RESEARCH 2016; 57:307-11. [PMID: 26838131 PMCID: PMC4915538 DOI: 10.1093/jrr/rrv101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/02/2015] [Accepted: 12/07/2015] [Indexed: 05/22/2023]
Abstract
Variations in relative biological effectiveness (RBE) from a fixed value of 1.1 are critical in proton beam therapy. To date, studies estimating RBE at multiple positions relative to the spread-out Bragg peak (SOBP) have been predominantly performed using passive scattering methods, and limited data are available for spot-scanning beams. Thus, to investigate the RBE of spot-scanning beams, Chinese hamster fibroblast V79 cells were irradiated using the beam line at the Hokkaido University Hospital Proton Therapy Center. Cells were placed at six different depths, including the entrance of the proton beam and the proximal and distal part of the SOBP. Surviving cell fractions were analyzed using colony formation assay, and cell survival curves were obtained by the curve fitted using a linear-quadratic model. RBE10 and RBE37 were 1.15 and 1.21 at the center of the SOBP, respectively. In contrast, the distal region showed higher RBE values (1.50 for RBE10 and 1.85 for RBE37). These results are in line with those of previous studies conducted using passive scattering proton beams. Taken together, these data strongly suggest that variations in RBE should be considered during treatment planning for spot-scanning beams as well as for passive scattering proton beams.
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Affiliation(s)
- Kenichiro Maeda
- Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Taeko Matsuura
- Department of Medical Physics, Proton Beam Therapy Center, Hokkaido University Hospital
| | - Tohru Yamamori
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Motofumi Suzuki
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Masaki Nagane
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Jin-Min Nam
- Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education, Hokkaido University
| | - Osamu Inanami
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Hiroki Shirato
- Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education, Hokkaido University
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26
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Baumann M, Krause M, Overgaard J, Debus J, Bentzen SM, Daartz J, Richter C, Zips D, Bortfeld T. Radiation oncology in the era of precision medicine. Nat Rev Cancer 2016; 16:234-49. [PMID: 27009394 DOI: 10.1038/nrc.2016.18] [Citation(s) in RCA: 512] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Technological advances and clinical research over the past few decades have given radiation oncologists the capability to personalize treatments for accurate delivery of radiation dose based on clinical parameters and anatomical information. Eradication of gross and microscopic tumours with preservation of health-related quality of life can be achieved in many patients. Two major strategies, acting synergistically, will enable further widening of the therapeutic window of radiation oncology in the era of precision medicine: technology-driven improvement of treatment conformity, including advanced image guidance and particle therapy, and novel biological concepts for personalized treatment, including biomarker-guided prescription, combined treatment modalities and adaptation of treatment during its course.
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Affiliation(s)
- Michael Baumann
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden
- OncoRay - National Center for Radiation Research in Oncology (NCRO), Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstrasse 74, 01307 Dresden
- National Center for Tumor Diseases (NCT), Fetscherstrasse 74, 01307 Dresden
- German Cancer Consortium (DKTK) Dresden, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Oncology, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Mechthild Krause
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden
- OncoRay - National Center for Radiation Research in Oncology (NCRO), Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstrasse 74, 01307 Dresden
- National Center for Tumor Diseases (NCT), Fetscherstrasse 74, 01307 Dresden
- German Cancer Consortium (DKTK) Dresden, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Oncology, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Jürgen Debus
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), University of Heidelberg Medical School and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), Im Neuenheimer Feld 460, 69120 Heidelberg
- Heidelberg Ion Therapy Center (HIT), Department of Radiation Oncology, University of Heidelberg Medical School, Im Neuenheimer Feld 400, 69120 Heidelberg
- German Cancer Consortium (DKTK) Heidelberg, Germany
| | - Søren M Bentzen
- Department of Epidemiology and Public Health and Greenebaum Cancer Center, University of Maryland School of Medicine, 22 S Greene Street S9a03, Baltimore, Maryland 21201, USA
| | - Juliane Daartz
- Department of Radiation Oncology, Physics Division, Massachusetts General Hospital and Harvard Medical School, 1000 Blossom Street Cox 362, Boston, Massachusetts 02114, USA
| | - Christian Richter
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden
- OncoRay - National Center for Radiation Research in Oncology (NCRO), Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstrasse 74, 01307 Dresden
- National Center for Tumor Diseases (NCT), Fetscherstrasse 74, 01307 Dresden
- German Cancer Consortium (DKTK) Dresden, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Daniel Zips
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- German Cancer Consortium Tübingen, Postfach 2669, 72016 Tübingen
- Department of Radiation Oncology, Faculty of Medicine and University Hospital Tübingen, Eberhard Karls Universität Tübingen, Hoppe-Seyler-Strasse 3, 72016 Tübingen, Germany
| | - Thomas Bortfeld
- Department of Radiation Oncology, Physics Division, Massachusetts General Hospital and Harvard Medical School, 1000 Blossom Street Cox 362, Boston, Massachusetts 02114, USA
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Chowdhry VK, Liu L, Goldberg S, Adams JA, De Amorim Bernstein K, Liebsch NJ, Niemierko A, Chen YL, DeLaney TF. Thoracolumbar spinal cord tolerance to high dose conformal proton–photon radiation therapy. Radiother Oncol 2016; 119:35-9. [DOI: 10.1016/j.radonc.2016.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/29/2015] [Accepted: 01/03/2016] [Indexed: 12/25/2022]
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28
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Shuryak I, Sun Y, Balajee AS. Advantages of Binomial Likelihood Maximization for Analyzing and Modeling Cell Survival Curves. Radiat Res 2016; 185:246-56. [DOI: 10.1667/rr14195.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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29
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Iwata H, Ogino H, Hashimoto S, Yamada M, Shibata H, Yasui K, Toshito T, Omachi C, Tatekawa K, Manabe Y, Mizoe JE, Shibamoto Y. Spot Scanning and Passive Scattering Proton Therapy: Relative Biological Effectiveness and Oxygen Enhancement Ratio in Cultured Cells. Int J Radiat Oncol Biol Phys 2016; 95:95-102. [PMID: 27084632 DOI: 10.1016/j.ijrobp.2016.01.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/16/2015] [Accepted: 01/11/2016] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine the relative biological effectiveness (RBE), oxygen enhancement ratio (OER), and contribution of the indirect effect of spot scanning proton beams, passive scattering proton beams, or both in cultured cells in comparison with clinically used photons. METHODS AND MATERIALS The RBE of passive scattering proton beams at the center of the spread-out Bragg peak (SOBP) was determined from dose-survival curves in 4 cell lines using 6-MV X rays as controls. Survival of 2 cell lines after spot scanning and passive scattering proton irradiation was then compared. Biological effects at the distal end region of the SOBP were also investigated. The OER of passive scattering proton beams and 6 MX X rays were investigated in 2 cell lines. The RBE and OER values were estimated at a 10% cell survival level. The maximum degree of protection of radiation effects by dimethyl sulfoxide was determined to estimate the contribution of the indirect effect against DNA damage. All experiments comparing protons and X rays were made under the same biological conditions. RESULTS The RBE values of passive scattering proton beams in the 4 cell lines examined were 1.01 to 1.22 (average, 1.14) and were almost identical to those of spot scanning beams. Biological effects increased at the distal end of the SOBP. In the 2 cell lines examined, the OER was 2.74 (95% confidence interval, 2.56-2.80) and 3.08 (2.84-3.11), respectively, for X rays, and 2.39 (2.38-2.43) and 2.72 (2.69-2.75), respectively, for protons (P<.05 for both cells between X rays and protons). The maximum degree of protection was significantly higher for X rays than for proton beams (P<.05). CONCLUSIONS The RBE values of spot scanning and passive scattering proton beams were almost identical. The OER was lower for protons than for X rays. The lower contribution of the indirect effect may partly account for the lower OER of protons.
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Affiliation(s)
- Hiromitsu Iwata
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan; Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
| | - Hiroyuki Ogino
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan
| | - Shingo Hashimoto
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan; Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Maho Yamada
- Department of Radiation Oncology, Nagoya City West Medical Center, Nagoya, Japan
| | - Hiroki Shibata
- Department of Proton Therapy Technology, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Keisuke Yasui
- Department of Proton Therapy Technology, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Toshiyuki Toshito
- Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Chihiro Omachi
- Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Kotoha Tatekawa
- Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshihiko Manabe
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Jun-Etsu Mizoe
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan
| | - Yuta Shibamoto
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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30
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George KA, Hada M, Cucinotta FA. Biological Effectiveness of Accelerated Protons for Chromosome Exchanges. Front Oncol 2015; 5:226. [PMID: 26539409 PMCID: PMC4610205 DOI: 10.3389/fonc.2015.00226] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/30/2015] [Indexed: 11/17/2022] Open
Abstract
We have investigated chromosome exchanges induced in human cells by seven different energies of protons (5-2500 MeV) with LET values ranging from 0.2 to 8 keV/μm. Human lymphocytes were irradiated in vitro and chromosome damage was assessed using three-color fluorescence in situ hybridization chromosome painting in chemically condensed chromosomes collected during the first cell division post irradiation. The relative biological effectiveness (RBE) was calculated from the initial slope of the dose-response curve for chromosome exchanges with respect to low dose and low dose-rate γ-rays (denoted as RBEmax), and relative to acute doses of γ-rays (denoted as RBEγAcute). The linear dose-response term was similar for all energies of protons, suggesting that the decrease in LET with increasing proton energy was balanced by the increase in dose from the production of nuclear secondaries. Secondary particles increase slowly above energies of a few hundred megaelectronvolts. Additional studies of 50 g/cm(2) aluminum shielded high-energy proton beams showed minor differences compared to the unshielded protons and lower RBE values found for shielded in comparison to unshielded beams of 2 or 2.5 GeV. All energies of protons produced a much higher percentage of complex-type chromosome exchanges when compared to acute doses of γ-rays. The implications of these results for space radiation protection and proton therapy are discussed.
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Affiliation(s)
- Kerry A. George
- Wyle Science, Technology and Engineering Group, Houston, TX, USA
| | - Megumi Hada
- Wyle Science, Technology and Engineering Group, Houston, TX, USA
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Polster L, Schuemann J, Rinaldi I, Burigo L, McNamara AL, Stewart RD, Attili A, Carlson DJ, Sato T, Ramos Méndez J, Faddegon B, Perl J, Paganetti H. Extension of TOPAS for the simulation of proton radiation effects considering molecular and cellular endpoints. Phys Med Biol 2015; 60:5053-70. [PMID: 26061666 DOI: 10.1088/0031-9155/60/13/5053] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aim of this work is to extend a widely used proton Monte Carlo tool, TOPAS, towards the modeling of relative biological effect (RBE) distributions in experimental arrangements as well as patients. TOPAS provides a software core which users configure by writing parameter files to, for instance, define application specific geometries and scoring conditions. Expert users may further extend TOPAS scoring capabilities by plugging in their own additional C++ code. This structure was utilized for the implementation of eight biophysical models suited to calculate proton RBE. As far as physics parameters are concerned, four of these models are based on the proton linear energy transfer, while the others are based on DNA double strand break induction and the frequency-mean specific energy, lineal energy, or delta electron generated track structure. The biological input parameters for all models are typically inferred from fits of the models to radiobiological experiments. The model structures have been implemented in a coherent way within the TOPAS architecture. Their performance was validated against measured experimental data on proton RBE in a spread-out Bragg peak using V79 Chinese Hamster cells. This work is an important step in bringing biologically optimized treatment planning for proton therapy closer to the clinical practice as it will allow researchers to refine and compare pre-defined as well as user-defined models.
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Affiliation(s)
- Lisa Polster
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA. Experimental Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
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