Journal of Clinical Biochemistry and Nutrition
Online ISSN : 1880-5086
Print ISSN : 0912-0009
ISSN-L : 0912-0009
A quantitative analysis of carbon-ion beam-induced reactive oxygen species and redox reactions
Ken-ichiro MatsumotoMinako NyuiMegumi UenoYukihiro OgawaIkuo Nakanishi
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JOURNAL FREE ACCESS Advance online publication

Article ID: 18-34

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Abstract

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.

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