Radiolabelling of peptides for diagnosis and therapy of non-oncological diseases.

Radiolabelled peptides have significant potential as radiopharmaceuticals for the diagnosis and therapy of receptor-expressing diseases. Methods have been developed for labelling peptides with a variety of radionuclides having a broad range of chemical and physical properties. These methods include both direct (where the radionuclide is bound directly to one or more atoms of the peptide structure) and indirect techniques in which bifunctional coupling agents are employed. Although most commonly applied to date in the field of oncology, a significant number of applications in non-oncological diseases have also been proposed and these can be expected to expand as the technology progresses. An overview is presented of some peptide-receptor systems in radiopharmaceutical development and the techniques which have been employed to radiolabel these peptides with isotopes of iodine, yttrium, indium, gallium, copper and technetium. While many of the examples employed are derived from cancer related indications, identical radiopharmaceutical chemistry can also be applied to peptides with applications in the fields of immunology, infection and other inflammatory conditions.