@misc{oai:repo.qst.go.jp:00070113,
 author = {Hirayama, Ryoichi and Matsumoto, Yoshitaka and Noguchi, Miho and Takase, Nobuhiro and Kase, Yuki and Tsuruoka, Chizuru and Matsufuji, Naruhiro and Ito, Atsushi and Ando, Koichi and Okayasu, Ryuichi and Furusawa, Yoshiya and 平山 亮一 and 松本 孔貴 and 鶴岡 千鶴 and 松藤 成弘 and 伊藤 敦 and 岡安 隆一 and 古澤 佳也},
 month = {May},
 note = {The contribution of indirect action mediated by OH radicals in cell killing can be estimated from the maximum degree of protection by dimethylsulfoxide (DMSO), which suppresses indirect action without affecting direct action.  Exponentially growing Chinese hamster ovary cells under hypoxic condition were exposed to high-LET radiations of 15 to 480 keV/micrometer 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.   The contribution was estimated to be 22% at an LET of 480 keV/micrometer.  The RBE determined at a survival level of 10% increased with LET, reaching a maximum value of 5.06 at 200 keV/micrometer, and decreased thereafter.  When the RBE was estimated separately for direct action (RBED) and indirect action (RBEI); the RBED was greater than RBEI over the ion LET range tested.  RBED increased with increasing LET and reached a peak value of 9.10 at 480 keV/micrometer.  RBEI also peaked at 90 keV/micrometer, but with a value of 2.61.  Thus the direct action of heavy-ion beams gives a remarkably higher RBE for cell killing than indirect action., PTCOG 49},
 title = {Contributions of direct and indirect actions in cell killing by high-LET radiations under hypoxic condition},
 year = {2010}
}