Steel G G, McMillan T J, Peacock J H
Radiotherapy Research Unit, Institute of Cancer Research, Sutton, Surrey, U.K.
Int J Radiat Biol. 1989 Nov;56(5):525-37. doi: 10.1080/09553008914551691.
Substantial developments have been made during the 1980s in the radiobiology of human tumours, in particular in studies of the radiosensitivity of human tumour cells. It is now clear that tumour cells differ considerably in radiosensitivity, to an extent that by itself is capable of explaining the clinical response of tumours to radiotherapy. There also is evidence that the radiosensitivity of human tumour cell lines to low radiation doses correlates with clinical experience. Irradiation at low dose rate amplifies the differences between cell lines. In conjunction with mathematical modelling, a study of the dose-rate effect also allows a distinction to be drawn between repairable and non-repairable damage. The differences seen between cell lines at low acute doses or low dose rates are associated with the non-repairable component. The most radiosensitive cell lines have a steep component of non-repairable damage and they give the impression of being recovery-deficient; this may, however, be incorrect for when evaluated at constant dose levels recovery is found to increase with increasing radiosensitivity. This leads to the view that recovery from radiation damage may reflect the amount of recoverable damage inflicted rather than the 'capacity' of the cells to recover.
20世纪80年代，人类肿瘤放射生物学领域取得了重大进展，尤其是在人类肿瘤细胞放射敏感性研究方面。现在很清楚，肿瘤细胞的放射敏感性差异很大，这种差异本身就能够解释肿瘤对放射治疗的临床反应。也有证据表明，人类肿瘤细胞系对低辐射剂量的放射敏感性与临床经验相关。低剂量率照射会放大细胞系之间的差异。结合数学建模，对剂量率效应的研究还可以区分可修复损伤和不可修复损伤。在低急性剂量或低剂量率下细胞系之间的差异与不可修复成分有关。放射敏感性最高的细胞系具有陡峭的不可修复损伤成分，给人的印象是缺乏修复能力；然而，当在恒定剂量水平下评估时，会发现随着放射敏感性的增加，修复能力也会增强，因此这种印象可能是错误的。这导致一种观点，即辐射损伤的修复可能反映了所造成的可修复损伤的量，而不是细胞的“修复能力”。
