Computer simulation of the earliest processes of radiation biological effects of; Direct and indirect effects of DNA damage

Kai, Takeshi   ; Toigawa, Tomohiro   ; Matsuya, Yusuke  ; Hirata, Yuho   ; Tezuka, Tomoya*; Tsuchida, Hidetsugu*; Ito, Yuma*; Yokoya, Akinari*

Irradiation of living systems forms complex DNA damage that induces biological effects in very rare cases. This complex DNA damage is called cluster damage and is very difficult to detect experimentally. In this study, we have developed physical and chemical codes for analyzing DNA damage, and are working to elucidate the formation mechanism of cluster damage. In this study, we analyzed the results of calculations in a simple system in which energy is deposited to DNA and secondary electrons are emitted, and showed that the formation mechanism of cluster damage strongly depends on the deposition energy to DNA. This scientific insight is expected to contribute to the elucidation of the repair mechanism of DNA damage and lead to the elucidation of radiation biological effects.