Methods The surviving cell number and surviving fraction (SF) of MCF 7 and Colo 205 cell lines following irradiation with 2,4,and 8 Gy were measured by using Courtenay Mills clonogenic and growth assays.

• 方法选用人类乳腺癌MCF?7及结肠癌Colo205细胞株，在接受2Gy、4Gy、8Gy放射处理后，用以上两种方法检测活存的肿瘤细胞数。