A Review on Technetium and Rhenium Based Radiopharmaceuticals for Diagnostic Imaging and Therapeutic Nuclear Medicine

Radionuclides (radioisotopes) are radioactive atoms with specific nuclear properties that have found an application in medical diagnostic imaging and radiotherapy in the form of various radiopharmaceuticals. Rhenium (Re) and technetium (Tc) have shown significant potential in nuclear medicine due to the prospective applications of rhenium radionuclides 186Re and 188Re in therapeutic nuclear medicine and technetium radionuclide 99mTc in medical diagnostic imaging. 186Re and 188Re radionuclides are both γ and β-emitting agents, while 99mTc radionuclide is only a γ-emitting agent; they exhibit favorable nuclear properties for medical imaging and therapy. Rhenium and technetium based radiopharmaceuticals are discussed in this review as they are widely applied in medical diagnostic imaging and therapeutic nuclear medicine in Europe and other parts of the world. Rhenium radionuclide agents are not yet approved for use in the United States. The nuclear properties of medical 186Re, 188Re and 99mTc radionuclides and their production and incorporation into radiopharmaceuticals are discussed. Stabilization and biodistribution (pharmacokinetics) of rhenium and technetium based radiopharmaceuticals from the administered site to the targeted organ during imaging and therapy are also clarified. Finally the classification of rhenium- and technetium-based radiopharmaceuticals, and their most common uses in nuclear medicine are discussed.