Rhenium Complexes in Nuclear Medicine

Abstract

Radioactive isotopes of rhenium, ¹⁸⁶Re and ¹⁸⁸Re, have been suggested as candidates for radioimmunotherapy because of their nuclear properties (energetic ß particles and imageable gamma photons). ¹⁸⁸Re is produced using a ¹⁸⁸W/¹⁸⁸Re generator. Neutron irradiation of ¹⁸⁵Re is used for the preparation of ¹⁸⁶Re. Rhenium and technetium complexes have similar physical properties, such as structure and lipophilicity, but some chemical properties are different. For example, the higher oxidation states of rhenium are more stable (reduced rhenium radiopharmaceuticals are prone to reoxidation to perrhenate) than those of technetium. Perrhenate is mostly reduced with tin(II) chloride in the presence of a suitable ligand. Perrhenate colloids, complexes of rhenium with diphosphonates, disulfanylsuccinate, sulfanylacetate and glycinate, synthetic peptide RC-160, and antibody conjugates with rhenium are studied from the point of view of their synthesis, chemical properties and pharmacokinetic properties. Possible therapeutic applications of individual complexes are indicated. A survey of labelled Re compounds for verified therapeutic applications is given.