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Zakaria AM, Lertnaisat P, Islam MM, Meesungnoen J, Katsumura Y, Jay-Gerin JP. Yield of the Fricke dosimeter irradiated with the recoil α and Li ions of the 10B( n, α) 7Li nuclear reaction: effects of multiple ionization and temperature. CAN J CHEM 2021. [DOI: 10.1139/cjc-2020-0381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Monte Carlo track chemistry simulations were used to investigate the effects of multiple ionization (MI) of water on the yields (G values) of the ferrous sulfate (Fricke) dosimeter, which was irradiated with low-energy α and lithium ion recoils from the 10B(n,α)7Li nuclear reaction as a function of temperature from 25 to 350 °C. Calculations were performed individually for 1.47 MeV α-particles and 0.84 MeV lithium nuclei with dose-average linear energy transfer (LET) values of ∼196 and 225 keV/µm at 25 °C, respectively. The total yields were obtained by summing the G values for each recoil α and Li ion weighted with its fraction of the total energy absorbed. At room temperature, our G(Fe3+) values calculated under aerated and deaerated conditions only agreed well with the experimental results, provided the MI of water was incorporated in the simulations. This strongly supports the importance of the role of MI of water in the high-LET radiolysis of water. We also simulated the effects of MI of water on G-values for the primary species of the radiolysis of deaerated 0.4 M H2SO4 aqueous solutions by 10B(n,α)7Li recoils. As with the Fricke dosimeter, the best agreement between experiment and simulation was found at 25 °C when the MI of water was included in the simulations. It was also shown that G(Fe3+) decreases slightly as a function of temperature over the range of 25–350 °C. However, at elevated temperatures, no experimental data were available with which to compare our results.
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Affiliation(s)
- Abdullah Muhammad Zakaria
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Phantira Lertnaisat
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Muhammad Mainul Islam
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Baxter Healthcare Corporation, 89 Centre Street South, Alliston, ON L9R 1W7, Canada
| | - Jintana Meesungnoen
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Yosuke Katsumura
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Nuclear Professional School, School of Engineering, The University of Tokyo, Shirakata-shirane 2-22, Tokai-mura, Naka-gun, Ibaraki 319-1188, Japan
| | - Jean-Paul Jay-Gerin
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
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Alanazi A, Meesungnoen J, Jay-Gerin JP. Linear energy transfer dependence of transient yields in water irradiated by 150 keV – 500 MeV protons in the limit of low dose rates. CAN J CHEM 2020. [DOI: 10.1139/cjc-2020-0113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
FLASH radiotherapy is a new irradiation method in which large doses of ionizing radiation are delivered to tumors almost instantly (a few milliseconds), paradoxically sparing healthy tissue while preserving anti-tumor activity. Although this technique is primarily studied in the context of electron and photon therapies, proton delivery at high dose rates can also reduce the adverse side effects on normal cells. So far, no definitive mechanism has been proposed to explain the differences in the responses to radiation between tumor and normal tissues. Given that living cells and tissues consist mainly of water, we set out to study the effects of high dose rates on the radiolysis of water by protons in the energy range of 150 keV – 500 MeV (i.e., for linear energy transfer (LET) values between ∼72.2 and 0.23 keV/μm, respectively) using Monte Carlo simulations. To validate our methodology, however, we, first, report here the results of our calculations of the yields (G values) of the radiolytically produced species, namely the hydrated electron ([Formula: see text]), •OH, H•, H2, and H2O2, for low dose rates. Overall, our simulations agree very well with the experiment. In the presence of oxygen, [Formula: see text] and H• atoms are rapidly converted into superoxide anion or hydroperoxyl radicals, with a well-defined maximum of [Formula: see text] at ∼1 μs. This maximum decreases substantially when going from low-LET 500 MeV to high-LET 150 keV irradiating protons. Differences in the geometry of the proton track structure with increasing LET readily explain this diminution in [Formula: see text] radicals.
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Affiliation(s)
- Ahmed Alanazi
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Jintana Meesungnoen
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Jean-Paul Jay-Gerin
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
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Peukert D, Incerti S, Kempson I, Douglass M, Karamitros M, Baldacchino G, Bezak E. Validation and investigation of reactive species yields of Geant4-DNA chemistry models. Med Phys 2018; 46:983-998. [PMID: 30536689 DOI: 10.1002/mp.13332] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/22/2018] [Accepted: 12/02/2018] [Indexed: 11/08/2022] Open
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.
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Affiliation(s)
- Dylan Peukert
- Future Industries Institute, University of South Australia, Adelaide, SA, Australia.,Division of ITEE, University of South Australia, Adelaide, SA, Australia
| | - Sebastien Incerti
- Univ. Bordeaux, CENBG, UMR 5797, Gradignan, F-33170, France.,CNRS, IN2P3, CENBG, UMR 5797, Gradignan, F-33170, France
| | - Ivan Kempson
- Future Industries Institute, University of South Australia, Adelaide, SA, Australia
| | - Michael Douglass
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA, Australia.,Department of Physics, University of Adelaide, Adelaide, SA, Australia
| | - Mathieu Karamitros
- Radiation Laboratory, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Gérard Baldacchino
- LIDYL, UMR 9222, CEA-CNRS-Université Paris-Saclay, CEA Paris-Saclay, F-91191, Gif sur Yvette, France
| | - Eva Bezak
- Department of Physics, University of Adelaide, Adelaide, SA, Australia.,Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, SA, Australia
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