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Direct and Indirect Actions to High-LET Radiations
https://repo.qst.go.jp/records/64013
https://repo.qst.go.jp/records/64013b1a2d8ad-15e5-4847-abed-c3aaf4d0ff05
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2010-09-22 | |||||
| タイトル | ||||||
| タイトル | Direct and Indirect Actions to High-LET Radiations | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Hirayama, Ryoichi
× Hirayama, Ryoichi× Matsumoto, Yoshitaka× Kase, Yuki× Noguchi, Miho× Takase, Nobuhiro× Uzawa, Akiko× Ito, Atsushi× Matsufuji, Naruhiro× Ando, Koichi× Okayasu, Ryuichi× Furusawa, Yoshiya× 平山 亮一× 松本 孔貴× 鵜澤 玲子× 伊藤 敦× 松藤 成弘× 岡安 隆一× 古澤 佳也 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | The biological effects of radiation originate principally from damages to DNA. DNA damage by photon radiation as well as heavy ions, is induced by a combination of direct and indirect actions. The contribution of indirect actions in cell killing can be estimated from the maximum degree of protection by dimethylsulfoxide (DMSO), which suppresses OH radical-mediated indirect action, without affecting the direct action. Exponentially growing Chinese hamster V79 cells were exposed to high LET radiation of 20 to 2106 keV/µm in the presence or absence of DMSO, and their survival was determined using a colony formation assay. The contribution of indirect action to cell killing decreased with increasing LET. However, the contribution did not reach zero even at very high LETs, and was estimated to be 32% at an LET of 2106 keV/µm. Therefore, even though the radiochemically estimated G value of OH radicals was nearly zero at an LET of 2000 keV/µm, indirect action by OH radicals substantially contributed to the biological effects of high LET radiations. The RBE determined at a survival level of 10% increased with LET, reaching a maximum value of 3 at around 100 keV/µm, and decreased thereafter. When the RBE was estimated separately for direct action and indirect action, the RBE resulting from indirect action had a peak at around 70 keV/µm with a gradual decrease with increasing LET. In contrast, the RBE of direct action peaked at around 200 keV/µm. Furthermore, the peak value for direct action (~6) was much higher than for indirect action (~2.5). Therefore, the direct action contributes more to the high RBE of high LET radiations than indirect action. | |||||
| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | KI-NIRS Joint Symposium on Carbon Ion Therapy | |||||
| 発表年月日 | ||||||
| 日付 | 2010-09-11 | |||||
| 日付タイプ | Issued | |||||
