The radiosensitivity of human tumour cells

Differences in radiosensitivity among human tumour cells are most clearly evident in the low-dose region. Studies at low dose rate suggest that there is a component of nonrecoverable damage which dominates the low-dose sensitivity. Split-dose experiments lead to the surprising conclusion that in radiosensitive cell lines the incidence of non-recoverable and recoverable damage are both higher than in more resistant cells. This can be understood in terms of a 'lesion severity' model of radiation cell killing. (author)