Application of laser-accelerated protons to the demonstration of DNA double-strand breaks in human cancer cells

Yogo, Akifumi; Sato, Katsutoshi; Nishikino, Masaharu; Mori, Michiaki; Teshima, Teruki*; Numasaki, Hodaka*; Murakami, Masao*; Demizu, Yusuke*; Akagi, Takashi*; Nagayama, Shinichi*; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Ikegami, Masahiro*; Tampo, Motonobu; Sakaki, Hironao; Suzuki, Masayuki; Daito, Izuru; Oishi, Yuji*; Sugiyama, Hironori*; Kiriyama, Hiromitsu; Okada, Hajime; Kanazawa, Shuhei; Kondo, Shuji; Shimomura, Takuya; Nakai, Yoshiki; Tanoue, Manabu*; Sasao, Hajime; Wakai, Daisuke*; Bolton, P.; Daido, Hiroyuki

We report the demonstrated irradiation effect of laser-accelerated protons on human cancer cells. (living) A549 cells are irradiated with quasi-monoenergetic proton bunches of 0.8-2.4 MeV with a single bunch duration of 15 ns. Irradiation with the proton dose of 20 Gy results in a distinct formation of -H2AX foci as an indicator of DNA double-strand breaks generated in the cancer cells. This is a pioneering result in view of future investigations on the radiobiological effects of laser-driven ion beams. Unique high-current and short-bunch features make laser-driven proton bunches an excitation source for time-resolved determination of radical yields.