Withers H R, Mason K A, Taylor J M
Department of Radiation Oncology, UCLA.
Radiother Oncol. 1993 Mar;26(3):238-43. doi: 10.1016/0167-8140(93)90265-a.
The near linearity of cellular dose-survival curves for neutrons facilities back-extrapolation to their origin at zero dose. This zero dose intercept is the number of clonogenic cells per circumference, from which the average number of clonogenic cells per crypt can be calculated. The average estimate of clonogenic cell number per crypt (k) from back-extrapolation of 11 single dose neutron survival curves to a common intercept was 100. Multifraction experiments provide an even better estimate of k because more complete dose survival curves can be constructed on the assumption of an equal effect per equal dose fraction. The short back-extrapolation of five such curves to a common intercept yields an estimated k value of 123 (108-140, 95% confidence interval) cells per crypt. These k values were higher than those estimated by Hendry's two-dose gamma-ray method.
中子的细胞剂量存活曲线接近线性，便于外推至零剂量原点。这个零剂量截距是每个肠周的克隆形成细胞数，据此可计算每个隐窝的克隆形成细胞平均数。将11条单剂量中子存活曲线外推至共同截距，得出每个隐窝克隆形成细胞数（k）的平均估计值为100。多分割实验能更好地估计k值，因为基于等剂量分割产生等效应的假设，可以构建更完整的剂量存活曲线。将5条这样的曲线短距离外推至共同截距，得出每个隐窝的k值估计为123（108 - 140，95%置信区间）个细胞。这些k值高于亨德里双剂量伽马射线法估计的值。
