Beagle dogs were given subcutaneous implants of
plutonium in their forepaws to mimic hand
wounds received by workers accidentally contaminated with
plutonium. Ten dogs received 9.46 +/- 0.43 mu Ci of
plutonium oxide, and eight dogs received 1.25 +/- 0.60 mu Ci of
plutonium nitrate. Surviving dogs were sacrificed at 8 and 5 yr, respectively, after exposure, and radionanalyses were performed on the injection site, regional lymph nodes, liver, spleen and bone. Histopathologic and autoradiographic examinations were performed on injection sites, regional lymph nodes, livers, spleens, kidneys and grossly observed lesions. The injected paws sequestered 21 and 16%, respectively, of the injected activity from
plutonium oxide and
plutonium nitrate in hypocellular
scar tissue. The highest concentrations of translocated
radionuclides were found in the regional lymph nodes. Histopathologic and autoradiographic examinations of regional lymph nodes showed that the alpha activity was largely sequestered by
scar tissue that replaced lymphoid parenchyma in the
plutonium-
oxide-injected dogs. In the
plutonium-nitrate-injected dogs, activity was widely distributed in relatively intact regional lymph nodes. The liver had the next highest concentration for both
radionuclides; activity was present as alpha stars. The spleen had the next highest concentration for
plutonium-
oxide-injected dogs, although concentrations in the spleen were lower than the skeleton in the
plutonium-nitrate-injected dogs.
Osteosarcomas and
hepatomas were present in one dog injected with
plutonium oxide. There does not appear to be any unique risk for dogs related to the subcutaneous route of exposure to
plutonium.