不同LET的重离子辐射对DSB诱导的影响

LET Effects on Double-Strand Break Inducted with Heavy-Ion Irradiation

利用γ射线和不同LET的碳离子辐照小鼠B16黑色素瘤细胞的脱蛋白DNA ,采用脉冲场凝胶电泳结合荧光扫描技术研究了DNA双链断裂 (DSB)与LET之间的关系。结果表明 :不同LET重离子诱导的PR都随剂量的增加而增加 ,并在超过一定的剂量之后逐渐趋于一个准阈值 :而不同LET的重离子诱导的L值都与剂量呈线性关系 ;对于诱导DSB的RBE值则随着LET的增加先呈上升趋势 ,在LET超过 10 0ke μm后下降。

The deproteinized DNA samples of melanoma B16 were irradiated by γ ray and 12 C 6+ ion with different LETs.Pulsed-field gel electrophoresis was applied to compare DNA double-strand breaks (DSBs) in B16 cells induced by the different LETs 12 C 6+ beam. It shows that the percentages of DNA released from plug(PR) induced by heavy ion of different LETs increase with the rising dose and approach a similar quasi-threshold. L(DSB level) induced by heavy ion of different LETs has linear relationship with dose. The relative biological effectiveness(REB) of DSB induction incereases with the rising LET at first,but when the LET exceeds 100keV/μm,RBE begins decrease.