Therapeutic radiopharmaceuticals exert their radiobiological action through the emission of electrically charged particles (α++ particles, β− particles, Auger electrons) that deposit their energy within a limited range in tissue—from fraction of a micrometer to a few millimeters at most. The goal of radionuclide therapy is to cause radiobiological effect with irreversible damage to cell DNA, resulting in cell death. The radionuclides are linked to carrier molecules capable of selectively transporting the radiotracers to the target tissues (in the majority of cases it is used for oncological purpose). At the moment the main indications of radionuclides therapy include treatment of malignant or benign thyroid disease, neural crest-derived tumors, neuroendocrine tumors, Non Hodgkin’s lymphoma, metastatic bone disease and intraarterial therapy of liver tumors.