Radiometal complexes in molecular imaging and therapy

Radiometals have become increasingly important because of their use both for diagnostic molecular imaging and therapy in Nuclear Medicine. The focus is on the study of biochemical processes at cellular and sub-cellular level in order to detect metabolic abnormalities associated with various diseases. For that purpose, molecules that selectively accumulate in the organ or tissue of interest by a specific mechanism such as receptor binding or interaction with biomolecules are labeled with (99m)Tc, (68)Ga, (153)Sm, (186/188)Re, (177)Lu, among others and used as radiopharmaceuticals. However, considerable effort is necessary to combine these radionuclides with biomolecules relevant to different pathological conditions. Intensive research on the coordination chemistry of these metals has led to novel labeling methods that yield stable compounds which retained the original biological activity of the ligand. Chemical aspects and clinical applications will be reviewed in this paper.