中能碳离子束对不同贯穿深度上黑色素瘤B16细胞的辐照存活效应

Irradiated survival effect of melanoma B16 cells at different penetration depths of intermediate energy heavy-ion beams

测量了 4 9.30MeV u及经脊形过滤器展宽的Bragg峰的 74 .55MeV u12 C离子束在不同贯穿深度上辐射后黑色素瘤B16细胞的存活率。结果显示 ,以存活为终点的B16细胞生物学效应与碳离子束能量沉积同步增大 ,即Bragg或展宽的Bragg峰区内细胞存活率远低于离子束入射或出射通道处的细胞存活率。通过实验测量与剂量平均LET结合的线性平方模型理论计算存活曲线的比较 ,发现在实验测量误差范围内两者符合较好。提示

Survival fractions of melanoma B16 cells at different penetration depths exposed to 49.30MeV/u 12 C ion beam and modulated 74.55MeV/u 12 C ion beam with a ridge filter to form a spread-out Bragg peak (SOBP) were measured. The results show the survival response of B16 cells as the biological endpoint to heavy ions increases synchronously with the deposited energy along the beam traversal, that is, the survival fraction near or at the Bragg peak or SOBP is far lower than that at the beam's entrance or exit channel. Comparisons of the experimental data with calculated survival fractions at different depths predicted by the linear-quadratic survival model combined with dose-averaged LET display a good agreement within the experimental errors. It is prompted that the linear-quadratic model combined with dose-averaged LET possibly is a valid way to calculate the survival effect of B16 cells along the beam penetration under the exposure of the intermediate energy heavy-ion beam.