Does longevity in beagles injected with bone-seeking radionuclides depend upon radiation dose in the absence of known radiation effects?

Regression analyses of longevity as a function of skeletal radiation dose a mong groups of beagles injected with Ra-226, Ra-228, Th-228, Am-241, Sr-90 or monomeric Pu-239 suggested that at low doses and dose-rates (those at wh ich induced effects are low), age at death seems to be independent of dose when animals dying with specific radiation effects were excluded, although longevity does appear to be a function of dose when animals dying with esta blished radiation effects and at all doses were included. We conclude tenta tively that, for mammals receiving skeletal dose from bone-seeking radionuc lides at low doses and low dose-rates, longevity may not be dependent upon skeletal radiation dose in the absence of radiation-induced malignancies or other radiation effects.