[Dynamics of the microdistribution of 239Pu in immunocompetent structures of the rat spleen after administration of the nuclide in the nitrate form].

The histoautoradiographic study has demonstrated that during the first 24 hours following the administration, plutonium is distributed diffusely and in the form of aggregates corresponding to reticular cells of marginal and brain sinuses. In addition, after 7 days on, one could observe phagocytosis of 239Pu particles and aggregates by the interdigiting reticular cells and migration thereof into follicle region where the cooperative relations occur between T- and B-lymphocytes. The absorbed radiation dose in the interdigiting cells is estimated.