Quantitative estimation of low-LET penumbra area induced by heavy ion particles using OH radical induced guanine damage (8-OHdG ); Further analysis including background noise reduction process

Urano, Kenta; Ito, Atsushi*; Takano, Yuki*; Ouchi, Fumihisa*; Hirayama, Ryoichi*; Furusawa, Yoshiya*; Funayama, Tomoo*; Yokota, Yuichiro*

To evaluate a role of low LET penumbra region on the biological effects of heavy ions, we have been developing an method for visualizing penumbra using immunofluorescence staining of OH radical-induced guanine damage, 8-OHdG, which was induced on a thin DNA sheet by heavy-ion exposure under aqueous environment. In the last annual meeting, we reported LET and ion species dependence of penumbra area and suggested the increase of penumbra area with increasing LET and particle atomic number. However, the LET dependence seemed to be inconsistent with the theoretical study by Chatterjee and Schaefer. In the present study, we improved image analysis method by adding the reduction procedure of fluorescence background noise.