Survival of HeLa Cells Culturedin Vitroand Exposed to Protracted Gamma-irradiation

Abstract

Experiments are described in which S₃ HeLa cells were exposed to gamma-radiation at dose-rates of 9·5 and 19 rad/hour (chronic irradiation). The cell-survival, in terms of reproductive integrity, was compared with the same cell-line irradiated at 44·9 rad/min (acute irradiation). It was found that while a ‘type C’ multi-hit curve was necessary to describe the survival of cells irradiated at 44·9 rad/min, a simple exponential function of dose was sufficient to describe the survival at 9·5 and 19 rad/min. The data were compared with the results of Berry and Cohen (1962).