Variations in Radiosensitivity of a Mammalian Cell Line with Phase of the Growth Cycle

Abstract

IN recent years dose-survival curves have been published for a number of mammalian cell lines in culture following X-irradiation, and it is often assumed that the extrapolation number (n) and the 37 per cent survival dose (D₀) that characterize these curves are constants for a particular cell line. However, Lockart et al.¹ noted small differences in n and D₀ for different samples of HeLa S3 cells, and Bases² found that of two strains of HeLa cells only one gave consistent values of n and D₀. This communication describes variations in radiosensitivity with the phase of the growth cycle in rat sarcoma cells.