Quantitative analysis of quantum beam induced initial/primary chemical reactions relating to biological molecular damage

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K07739
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: UENO MEGUMI 国立研究開発法人量子科学技術研究開発機構, 放射線医学研究所 放射線規制科学研究部, 研究員 (30296826)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 放射線 / 重粒子線 / 炭素線 / 生物影響 / 活性酸素 / フリーラジカル / ヒドロキシルラジカル / 過酸化水素

Outline of Final Research Achievements

The purpose of this project is analyzing initial and/or primary chemical reactions of radiation-induced reactive oxygen species (ROS), which would trigger the biological reaction, based on quantification of ROS and its reactions. X-ray induced highly concentrated H2O2 clusters in water were detected and the inter-cluster distance was evaluated as 40-50 nm. Amounts of oxygen-independent H2O2 generation were increased with LET increasing, and oxygen-dependent H2O2 generation were decreased with LET increasing. Radiation induced plasmid DNA breakage was increased under hypoxic condition, by either X-ray or carbon-ion beam. A method for measuring lipid radical caused by radiation in oil was developed. Resolved oxygen in water was not always increase ROS generation by ionizing radiations, such as X-ray or carbon-ion beam.

Free Research Field

放射線化学

Academic Significance and Societal Importance of the Research Achievements

本研究の結果からは、これまで主な障害因子と考えられてきたヒドロキシルラジカルよりも、むしろ高濃度の過酸化水素の低酸素環境での反応性に注目すべきであろうと思われるデータが得られている。そのため、偏在したROSの局所での濃度（密度）を考慮した定量と、分子レベルのジオメトリーを考慮した反応解析を徹底し、各ROSの反応の相手（ターゲット分子）を予測することにより、新しいコンセプトの放射線化学および放射線生物影響評価への展開が期待できる。