Radiobiology with laser-accelerated ion beams; Application of the quasi-monoenergetic proton beamline

レーザー駆動陽子線による放射線生物学研究; 準単エネルギー陽子線照射装置の応用

余語 覚文; 前田 拓也*; 堀 利彦*; 榊 泰直; 小倉 浩一; 西内 満美子; 匂坂 明人; Bolton, P.; 村上 昌雄*; 近藤 公伯

Yogo, Akifumi; Maeda, Takuya*; Hori, Toshihiko*; Sakaki, Hironao; Ogura, Koichi; Nishiuchi, Mamiko; Sagisaka, Akito; Bolton, P.; Murakami, Masao*; Kondo, Kiminori

Human cancer cells are irradiated by laser-driven quasi-monoenergetic protons. Laser pulse intensities at the 510-W/cm level provide the source and acceleration field for protons that are subsequently transported by four energy-selective dipole magnets. The transport line delivers 2.25 MeV protons with an energy spread of 0.66 MeV and a bunch duration of 20 ns. The survival fraction of in-vitro cells from a human salivary gland tumor is measured with a colony formation assay following proton irradiation at dose levels up to 8 Gy, for which the single bunch does rate is 1 10 Gy/s and the effective dose rate is 0.2 Gy/s for 1-Hz repetition of irradiation. Relative biological effectiveness at the 10% survival fraction is measured to be 1.200.11 using protons with a linear energy transfer of 17.12.8 keV/m.