量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The amounts of reactive oxygen species generated in aqueous samples by irradiation with X-ray or clinical carbon-ion beams were quantified. Hydroxyl radical (•OH), hydrogen peroxide (H2O2), and the total amount of oxidation reactions, which occurred mainly because of •OH and/or hydroperoxy radicals (HO2•), were measured by electron paramagnetic resonance-based methods. •OH generation was expected to be localized on the track/range of the carbon-ion beam/X-ray, and mM and M levels of •OH generation were observed. Total •OH generation levels were identical at the same dose irrespective of whether X-ray or carbon-ion beam irradiation was used, and were around 0.28‒0.35 μmol/l/Gy. However, sparse •OH generation levels decreased with increasing linear energy transfer, and were 0.17, 0.15, and 0.09 μmol/l/Gy for X-ray, 20 keV/μm carbon-ion beam, and >100 keV/μm carbon-ion beam sources, respectively. H2O2 generation was estimated as 0.26, 0.20, and 0.17 μmol/l/Gy, for X-ray, 20 keV/μm carbon-ion beam, and >100 keV/μm carbon-ion beam sources, respectively, whereas the ratios of H2O2 generation per oxygen consumption were 0.63, 0.51, and 3.40, respectively. The amounts of total oxidation reactions were 2.74, 1.17, and 0.66 μmol/l/Gy, respectively. The generation of reactive oxygen species was not uniform at the molecular level.
A Quantitative Analysis of Carbon-Ion Beam-Induced Reactive Oxygen Species and RedOx Reactions
Matsumoto.K.2019.J.Clin.Biochem.Nutr.65.1-7.pdf
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