The pharmacokinetics of the Astatine-211 radiopharmaceutical was investigated after a single injection in male SD (Sprague–Dawley) rats that had normal and iodine-free diets. Twelve groups of SD male rats were examined in the study. The tested drug was intravenously injected into the tail vein of the animals once at a volume of 10 mL/kg and dose of 100 μCi per animal. In the study, the animals were subjected to necropsy at specific time points with retrieval of the organs and tissues for further analysis of the activity of the samples using a well-type scintillation gamma spectrometer. It was found that the $^{211}$At absorption by the thyroid in the male rats that had an iodine-free diet was greater than in the rats that had a conventional diet.
$^1$Skobeltsyn Institute of Nuclear Physics, M.V.Lomonosov Moscow State University.\
$^2$Shemyakin-Ovchinnikov Institute of bioorganic chemistry, Moscow region, Pushchino\
$^3$Department of of Nuclear Physics and Quantum Theory of Collisions, Faculty of Physics, M.V.Lomonosov Moscow State University\
$^4$Faculty of Physics, Lomonosov Moscow State University.