Dispersion of Alpha-Nuclides during Animal Experiments

The dispersions of short-lived radionuclides emitting a -particles, such as 223 Ra, 211 At, and 225 Ac, during animal experiments were measured for radiation safety management. These three radionuclides dispersed from mice were trapped using charcoal-impregnated filters, and those in feces were collected directly, and those in urine were recovered with bedding in a breeding cage. For all the radionuclides, uptakes by tissues were also further examined after dissection. The radioactivity of each radionuclide was evaluated with a g -ray scintillation counter using daughter nuclide. In tumor bearing mice, 211 At and 223 Ra accumulated in tumor tissues with high affinity and less accumulated in other tissues. It was noted that all the three radionuclides were not exhausted or evaporated from the breeding cages and the peak of excretions of the radionuclides in the animal experiments was observed within twenty-four hours.