RBE of tritium-beta exposure for the induction of the adaptive response and apoptosis; cellular defense mechanisms against the biological effects of ionizing radiation

When yeast cells are primed with sublethal doses of gamma radiation, they subsequently undergo an adaptive response and develop resistance to radiation, heat and mutagens. Based on this model, the relative ability of tritium-beta radiation to induce the adaptive response was assessed and tritium induced radiation resistance, thermal tolerance and mutation suppression were examined. The response of yeast cells to tritium was found to be similar as that to gamma radiation. Tritium's relative biological effectiveness (RBE) for induction of the adaptive response was established to be about 1. Studies with lymphocytes, on the other hand, established the RBE of tritium for the induction of apoptosis in human lymphocytes to be also 1.