Peacock J H, Eady J J, Edwards S M, McMillan T J, Steel G G
Radiotherapy Research Unit, Institute of Cancer Research, Sutton, Surrey, UK.
Int J Radiat Biol. 1992 Apr;61(4):479-87. doi: 10.1080/09553009214551241.
The radiation response of 15 mammalian cell lines comprising 11 human tumour, two human fibroblast and two murine lymphoma cell lines, has been analysed using the linear-quadratic equation. As well as using conventional analysis of acute dose-survival curves to derive values for alpha and beta (termed alpha ac and beta ac), low dose-rate and split-dose experiments have been used to derive independent values of alpha and beta (alpha 1dr and beta RR), respectively. alpha 1dr provides a measure of irrecoverable damage, the magnitude of which agreed well with the initial slope of the acute survival curve for most cell lines. beta RR derived from split-dose experiments represents a unique measure of recovery for each cell line. Large differences were found between individual values of beta ac and beta RR, especially in the radiosensitive cell lines. Since beta RR is a functional measure of recovery we suggest that this is the more relevant parameter in studies of dose sparing. The most striking result of this analysis was found in considering the alpha/beta ratios. No relationship was observed between alpha ac and beta ac resulting in values of alpha ac/beta ac ranging from 1 to 175. In contrast a positive correlation was observed between alpha 1dr beta RR in the 11 tumour cell lines, giving an alpha/beta ratio of 9.4 +/- 1.8 Gy. This observation of the relative constancy of the ratio for human tumour cells leads to an hypothesis about the role of initial damage as a determinant of radiosensitivity.
使用线性二次方程分析了15种哺乳动物细胞系的辐射反应，其中包括11种人类肿瘤细胞系、2种人类成纤维细胞系和2种鼠淋巴瘤细胞系。除了使用传统方法分析急性剂量存活曲线以得出α和β值（称为αac和βac）外，还采用了低剂量率和分次剂量实验分别得出α和β的独立值（α1dr和βRR）。α1dr提供了一种不可恢复损伤的度量，对于大多数细胞系而言，其大小与急性存活曲线的初始斜率非常吻合。从分次剂量实验得出的βRR代表了每个细胞系独特的恢复度量。发现βac和βRR的个体值之间存在很大差异，尤其是在放射敏感细胞系中。由于βRR是恢复的功能度量，我们认为这是剂量节省研究中更相关的参数。该分析最引人注目的结果是在考虑α/β比值时发现的。未观察到αac和βac之间的关系，导致αac/βac值范围为1至175。相比之下，在11种肿瘤细胞系中观察到α1dr和βRR之间呈正相关，α/β比值为9.4±1.8 Gy。对人类肿瘤细胞系该比值相对恒定的这一观察结果引发了关于初始损伤作为放射敏感性决定因素作用的假设。
