Chromosomal aberrations in Chinese hamster cells exposed in vitro to tritium-labelled thymidine or x-rays at--196 degrees C.

A comparison was made between the incidence of chromosomal aberrations in G2-phase first division Chinese hamster cells exposed to tritium labelled thymidine (dose range 54-522 rad) or to 250 kV X-rays (dose range 98-711 rad) at--196 degrees C. The dose-response relationship for chromatid aberrations, expressed as breaks per cell, appeared to be linear for intranuclear tritium whereas that for X-rays was curvilinear. For the dose range studied, cells exposed to X-rays were markedly less sensitive than tritium-incorporated cells where a transmutation effect may operate.