Radiometals: towards a new success story in nuclear imaging?

Several limitations of F-18 and other non-metallic isotopes have been emphasized by the development of macromolecular biotargeting agents for cancer, including peptides, antibodies, fragments and oligonucleotides, which typically have biological half-lives that are much longer than the radioactive half-life of F-18. Based on the F-18-FDG success story, we can wonder whether all critical criteria are or can be fulfilled for the radiometallated bioconjugates to start out from the crowd and which metals have the best chance of success. In this paper we give a brief overview of radiometal isotopes having the potential for PET imaging in terms of physical properties, production capacity and associated chemistry.