Proton Irradiations at Ultra-High Dose Rate vs. Conventional Dose Rate: Strong Impact on Hydrogen Peroxide Yield
| Autor: | Guillaume Blain, Johan Vandenborre, Daphnée Villoing, Vincent Fiegel, Giovanna Rosa Fois, Ferid Haddad, Charbel Koumeir, Lydia Maigne, Vincent Métivier, Freddy Poirier, Vincent Potiron, Stéphane Supiot, Noël Servagent, Grégory Delpon, Sophie Chiavassa |
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| Přispěvatelé: | Laboratoire de physique subatomique et des technologies associées (SUBATECH), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), ANR-16-IDEX-0007,NExT (I-SITE),NExT (I-SITE)(2016) |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Radiation Research Radiation Research, 2022, 198, pp.318-324. ⟨10.1667/RADE-22-00021.1⟩ |
| ISSN: | 0033-7587 |
| Popis: | International audience; During ultra-high dose rate (UHDR) external radiation therapy, healthy tissues appear to be spared while tumor control remains the same compared to conventional dose rate. However, the understanding of radiochemical and biological mechanisms involved are still to be discussed. This study shows how the hydrogen peroxide (H2O2) production, one of the reactive oxygen species (ROS), could be controlled by early heterogenous radiolysis processes in water during UHDR proton-beam irradiations. Pure water was irradiated in the plateau region (track-segment) with 68 MeV protons under conventional (0.2 Gy/s) and several UHDR conditions (40 Gy/s to 60 kGy/s) at the ARRONAX cyclotron. Production of H2O2 was then monitored using the Ghormley triiodide method. New values of GTS(H2O2) were added in conventional dose rate. A substantial decrease in H2O2 production was observed from 0.2 to 1.5 kGy/s with a more dramatic decrease below 100 Gy/s. At higher dose rate, up to 60 kGy/s, the H2O2 production stayed stable with a mean decrease of 38% ± 4%. This finding, associated to the decrease in the production of hydroxyl radical (•OH) already observed in other studies in similar conditions can be explained by the well-known spur theory in radiation chemistry. Thus, a two-step FLASH-RT mechanism can be envisioned: an early step at the microsecond scale mainly controlled by heterogenous radiolysis, and a second, slower, dominated by O2 depletion and biochemical processes. To validate this hypothesis, more measurements of radiolytic species will soon be performed, including radicals and associated lifetimes. |
| Databáze: | OpenAIRE |
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