Induction of Chromosome Aberrations and Cell Killing in Syrian Hamster Fibroblasts by γ-rays, X-rays and Fast Neutrons

Abstract

Chromosome aberrations were scored in BHK21 C13 Syrian hamster fibroblasts, exposed to ⁶⁰Co γ-rays, 250 kV X-rays, 15 MeV neutrons or neutrons of mean energy 2·1 MeV produced from the ⁹Be(d, n)¹⁰B reaction. The cells were irradiated in stationary phase, where they are concentrated in the G1 phase of the cell cycle. Within experimental uncertainty there was no detectable difference between the responses to ⁶⁰Co γ-rays and to 250 kV X-rays. The r.b.e. for the production of dicentrics, based on the ‘one-hit’ component of response, was (5 ± 2) for the 15 MeV neutrons and (12 ± 5) for the 2·1 MeV neutrons. For each radiation, a graph of the proportion of cells without a dicentric, centric ring or acentric fragment corresponded closely to the survival curve for stationary-phase cells obtained in the same experiment.