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5 results on '"Karamitros, Mathieu"'

1. Independent reaction times method in Geant4‐DNA: Implementation and performance

Author

Ramos‐Méndez, José, Shin, Wook‐Geun, Karamitros, Mathieu, Domínguez‐Kondo, Jorge, Tran, Ngoc Hoang, Incerti, Sebastien, Villagrasa, Carmen, Perrot, Yann, Štěpán, Václav, Okada, Shogo, Moreno‐Barbosa, Eduardo, and Faddegon, Bruce

Subjects
Medical and Biological Physics, Physical Sciences, Affordable and Clean Energy, Computer Simulation, DNA, Linear Energy Transfer, Models, Chemical, Monte Carlo Method, Reaction Time, Water, Geant4-DNA, independent reaction times, LET, Monte Carlo, radiolysis, track-structure, Other Physical Sciences, Biomedical Engineering, Oncology and Carcinogenesis, Nuclear Medicine & Medical Imaging, Biomedical engineering, Medical and biological physics
Abstract

PurposeThe simulation of individual particle tracks and the chemical stage following water radiolysis in biological tissue is an effective means of improving our knowledge of the physico-chemical contribution to the biological effect of ionizing radiation. However, the step-by-step simulation of the reaction kinetics of radiolytic species is the most time-consuming task in Monte Carlo track-structure simulations, with long simulation times that are an impediment to research. In this work, we present the implementation of the independent reaction times (IRT) method in Geant4-DNA Monte Carlo toolkit to improve the computational efficiency of calculating G-values, defined as the number of chemical species created or lost per 100 eV of deposited energy.MethodsThe computational efficiency of IRT, as implemented, is compared to that from available Geant4-DNA step-by-step simulations for electrons, protons and alpha particles covering a wide range of linear energy transfer (LET). The accuracy of both methods is verified using published measured data from fast electron irradiations for • OH and eaq- for time-dependent G-values. For IRT, simulations in the presence of scavengers irradiated by cobalt-60 γ-ray and 2 MeV protons are compared with measured data for different scavenging capacities. In addition, a qualitative assessment comparing measured LET-dependent G-values with Geant4-DNA calculations in pure liquid water is presented.ResultsThe IRT improved the computational efficiency by three orders of magnitude relative to the step-by-step method while differences in G-values by 3.9% at 1 μs were found. At 7 ps, • OH and eaq- yields calculated with IRT differed from recent published measured data by 5% ± 4% and 2% ± 4%, respectively. At 1 μs, differences were 9% ± 5% and 6% ± 7% for • OH and eaq- , respectively. Uncertainties are one standard deviation. Finally, G-values at different scavenging capacities and LET-dependent G-values reproduced the behavior of measurements for all radiation qualities.ConclusionThe comprehensive validation of the Geant4-DNA capabilities to accurately simulate the chemistry following water radiolysis is an ongoing work. The implementation presented in this work is a necessary step to facilitate performing such a task.

Published
2020

2. Validation and investigation of reactive species yields of Geant4‐DNA chemistry models.

Author

Peukert, Dylan, Incerti, Sebastien, Kempson, Ivan, Douglass, Michael, Karamitros, Mathieu, Baldacchino, Gérard, and Bezak, Eva

Subjects
DNA analysis, LINEAR energy transfer, CHEMICAL yield, RADIOBIOLOGY, COMPUTER simulation
Abstract

Purpose: Indirect biological damage due to reactive species produced in water radiolysis reactions is responsible for the majority of biological effect for low linear energy transfer (LET) radiation. Modeling water radiolysis and the subsequent interactions of reactive species, as well as track structures, is essential to model radiobiology on the microscale. Recently, chemistry models have been developed for Geant4‐DNA to be used in combination with the comprehensive existing physics models. In the current work, the first detailed, independent, in silico validation of all species yields with published experimental observations and comparison with other radiobiological simulations is presented. Additionally, the effect of LET of protons and heavier ions on reactive species yield in the model was examined, as well as the completeness of the chemical reactions following the radiolysis within the time after physical interactions simulated in the model. Methods: Yields over time of reactive species were simulated for water radiolysis by incident electrons, protons, alpha particles, and ions with various LETs using Geant4 and RITRACKS simulation tools. Water dissociation and recombination was simulated using Geant4 to determine the completeness of chemical reactions at the end of the simulation. Yield validation was performed by comparing yields simulated using Geant4 with experimental observations and other simulations. Validation was performed for all species for low LET radiation and the solvated electron and hydroxyl radical for high LET ions. Results: It was found that the Geant4‐DNA chemistry yields were generally in good agreement with experimental observations and other simulations. However, the Geant4‐DNA yields for the hydroxyl radical and hydrogen peroxide at the end of the chemistry stage were found to be respectively considerably higher and lower than the experimentally observed yields. Increasing the LET of incident hadrons increased the yield of secondary species and decreased the yield of primary species. The effect of LET on the yield of the hydroxyl radical at 100 ns simulated with Geant4 was in good agreement with experimental measurements. Additionally, by the end of the simulation only 40% of dissociated water molecules had been recombined and the rate of recombination was slowing. Conclusions: The yields simulated using Geant4 are within reasonable agreement with experimental observations. Higher LET radiation corresponds with increased yields of secondary species and decreased yields of primary species. These trends combined with the LET having similar effects on the 100 ns hydroxyl radical yield for Geant4 and experimental measurements indicate that Geant4 accurately models the effect of LET on radiolysis yields. The limited recombination within the modeled chemistry stage and the slowing rate of recombination at the end of the stage indicate potential long‐range indirect biological damage. [ABSTRACT FROM AUTHOR]

Published
2019
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3. Track structure modeling in liquid water: A review of the Geant4-DNA very low energy extension of the Geant4 Monte Carlo simulation toolkit

Author

Bernal, Mario A., Bordage, Marie Claude, Brown, Jeremy Michael Cooney, Davídková, Marie, Delage, E., El Bitar, Ziad Ei, Enger, Shirin A., Francis, Ziad, Guatelli, Susanna, Ivanchenko, Vladimir N., Karamitros, Mathieu, Kyriakou, Ioanna, Maigne, Lydia, Meylan, Sylvain, Murakami, Kouichi, Okada, Shogo, Payno, H., Perrot, Yann, Petrović, Ivan M., Pham, Q. T., Ristić-Fira, Aleksandra, Sasaki, Takashi, Stepan, Vaclav, Tran, Ngoc Hoang, Villagrasa, Carmen, and Incerti, Sebastien

Subjects
Ionizing radiation, Geant4-DNA, Radiolysis, Radiobiology, Monte Carlo
Abstract

Understanding the fundamental mechanisms involved in the induction of biological damage by ionizing radiation remains a major challenge of todays radiobiology research. The Monte Carlo simulation of physical, physicochemical and chemical processes involved may provide a powerful tool for the simulation of early damage induction. The Geant4-DNA extension of the general purpose Monte Carlo Geant4 simulation toolkit aims to provide the scientific community with an open source access platform for the mechanistic simulation of such early damage. This paper presents the most recent review of the Geant4-DNA extension, as available to Geant4 users since June 2015 (release 10.2 Beta). In particular, the review includes the description of new physical models for the description of electron elastic and inelastic interactions in liquid water, as well as new examples dedicated to the simulation of physicochemical and chemical stages of water radiolysis. Several implementations of geometrical models of biological targets are presented as well, and the list of Geant4-DNA examples is described.

Published
2015

4. Simulating radial dose of ion tracks in liquid water simulated with Geant4-DNA: A comparative study

Author

Incerti, Sebastien, Psaltaki, Maria G., Gillet, Pierre, Barberet, Ph., Bardies, M., Bernal, Mario A., Bordage, Marie Claude, Breton, Vincent, Davídková, Marie, Delage, E., El Bitar, Ziad Ei, Francis, Ziad, Guatelli, Susanna, Ivanchenko, A., Ivanchenko, Vladimir, Karamitros, Mathieu, Lee, Sebyeong, Maigne, Lydia, Meylan, Sylvain, Murakami, Kouichi, Nieminen, Petteri H., Payno, H., Perrot, Yann, Petrović, Ivan M., Pham, Q. T., Ristić-Fira, Aleksandra, Santin, Giovanni, Sasaki, Takashi, Seznec, Herve, Shin, Jae-ik, Stepan, Vaclav, Tran, Ngoc Hoang, Villagrasa, Carmen, Geant4-DNA Collaboration, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), National Technical University of Athens [Athens] (NTUA), Institut Universitaire du Cancer de Toulouse - Oncopole (IUCT Oncopole - UMR 1037), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-CHU Toulouse [Toulouse]-Institut National de la Santé et de la Recherche Médicale (INSERM), Instituto de Fisica 'Gleb Wataghin' (INSTITUTO DE FISICA 'GLEB WATAGHIN'), Universidade Estadual de Campinas (UNICAMP), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Department of Radiation Dosimetry, Nuclear Physics Institute of the AS CR, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, Faculty of Sciences, Université Saint-Joseph de Beyrouth (USJ), Centre for Medical Radiation Physics, University of Wollongong [Australia], Geant4 Associates International (G4AI), Ecoanalytica, Institut de Neurosciences cognitives et intégratives d'Aquitaine (INCIA), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-SFR Bordeaux Neurosciences-Centre National de la Recherche Scientifique (CNRS), Proton Therapy Center, National Cancer Center Korea, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), KEK (High energy accelerator research organization), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Vinča Institute of Nuclear Sciences, University of Belgrade [Belgrade], Ton Duc Thang University [Hô-Chi-Minh-City], Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Institut National de la Santé et de la Recherche Médicale (INSERM), Universidade Estadual de Campinas = University of Campinas (UNICAMP), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-SFR Bordeaux Neurosciences-Centre National de la Recherche Scientifique (CNRS), and Agence Spatiale Européenne = European Space Agency (ESA)

Subjects
Nuclear and High Energy Physics, Work (thermodynamics), Radiation transport, Physics::Medical Physics, Reference data (financial markets), Monte Carlo method, Ion, Deposition (phase transition), Statistical physics, Instrumentation, Monte Carlo, Physics, Energy depositions, [PHYS]Physics [physics], Geant4-DNA, Ion track, Geant4 dnas, Monte Carlo methods, Liquids, DNA, Analytical calculation, Monte- carlo simulations, Charged particle, Computational physics, Comparative studies, Liquid water, Dose, Dynamic Monte Carlo method
Abstract

International audience; An accurate modeling of radial energy deposition around ion tracks is a key requirement of radiation transport software used for simulations in radiobiology at the sub-cellular scale. The work presented in this paper is part of the on-going benchmarking of the "Geant4-DNA" physics processes and models, which are available in the Geant4 Monte Carlo simulation toolkit for the low energy transport of particles in liquid water. We present for the first time radial dose distributions of incident ion tracks simulated with "Geant4-DNA". Simulation results are compared to other results available in the literature, obtained from analytical calculations, step-by-step Monte Carlo simulations and measurements. They show a reasonable agreement with reference data. © 2014 Elsevier B.V. All rights reserved.

Published
2014
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5. Validation and investigation of reactive species yields of Geant4‐ DNA chemistry models

Author

Gérard Baldacchino, Dylan Peukert, Ivan M. Kempson, M. Karamitros, Eva Bezak, Sebastien Incerti, Michael Douglass, Flinders University of South Australia, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Biomolécules Excitées (DICO), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Adelaide, Peukert, Dylan, Incerti, Sebastien, Kempson, Ivan, Douglass, Michael, Karamitros, Mathieu, Baldacchino, Gerard, Bezak, Eva, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Dynamique et Interactions en phase Condensée (DICO), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
model validation, water radiolysis, Chemical Phenomena, Linear energy transfer, Electrons, Radiation chemistry, Solvated electron, 7. Clean energy, Dissociation (chemistry), 030218 nuclear medicine & medical imaging, Ion, radiation chemistry, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Humans, Molecule, Computer Simulation, Linear Energy Transfer, Monte Carlo, Chemistry, Water, DNA, General Medicine, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Models, Chemical, radiobiology, Chemical physics, 030220 oncology & carcinogenesis, Radiolysis, Hydroxyl radical, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Protons, Pulse Radiolysis, Monte Carlo Method
Abstract

Purpose: Indirect biological damage due to reactive species produced in water radiolysis reactions is responsible for the majority of biological effect for low linear energy transfer (LET) radiation. Modeling water radiolysis and the subsequent interactions of reactive species, as well as track structures, is essential to model radiobiology on the microscale. Recently, chemistry models have been developed for Geant4-DNA to be used in combination with the comprehensive existing physics models. In the current work, the first detailed, independent, in silico validation of all species yields with published experimental observations and comparison with other radiobiological simulations is presented. Additionally,the effect of LET of protons and heavier ions on reactive species yield in the model was examined, as well as the completeness of the chemical reactions following the radiolysis within the time after physical interactions simulated in the model. Methods: Yields over time of reactive species were simulated for water radiolysis by incident electrons,protons, alpha particles, and ions with various LETs using Geant4 and RITRACKS simulation tools. Water dissociation and recombination was simulated using Geant4 to determine the completeness of chemical reactions at the end of the simulation. Yield validation was performed by comparing yields simulated using Geant4 with experimental observations and other simulations. Validation was performed for all species for low LET radiation and the solvated electron and hydroxyl radical for high LET ions. Results: It was found that the Geant4-DNA chemistry yields were generally in good agreement with experimental observations and other simulations. However, the Geant4-DNA yields for the hydroxyl radical and hydrogen peroxide at the end of the chemistry stage were found to be respectively considerably higher and lower than the experimentally observed yields. Increasing the LET of incident hadrons increased the yield of secondary species and decreased the yield of primary species. The effect of LET on the yield of the hydroxyl radical at 100 ns simulated with Geant4 was in good agreement with experimental measurements. Additionally, by the end of the simulation only 40% of dissociated water molecules had been recombined and the rate of recombination was slowing. Conclusions: The yields simulated using Geant4 are within reasonable agreement with experimental observations. Higher LET radiation corresponds with increased yields of secondary species and decreased yields of primary species. These trends combined with the LET having similar effects on the 100 ns hydroxyl radical yield for Geant4 and experimental measurements indicate that Geant4accurately models the effect of LET on radiolysis yields. The limited recombination within the modeled chemistry stage and the slowing rate of recombination at the end of the stage indicate potential long-range indirect biological damage. Refereed/Peer-reviewed

Published
2019
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