A new and improved method for extending the half life of pharmaceuticalcompounds for use in diagnostic imaging or therapy uses a novel linker toattach a diagnostic or therapeutic moiety to a targeting peptide or anotherdiagnostic or therapeutic moiety. The resulting compound may have the generalformula M-N-O-P-Q, wherein M is the diagnostic or therapeutic moiety, N-O-P isthe linker of the present invention, and Q is the targeting peptide. Inanother embodiment the compounds may have the formula M-N-O-P-M, wherein M isindependently a diagnostic or therapeutic moiety and N-O-P is the linker ofthe invention. Methods for imaging or treating a patient using the compoundsof the invention are also provided. Methods and kits for preparing adiagnostic imaging agent from the compound are further provided. Methods forradiotherapy of a patient using the compounds are further provided, as aremethods for preparing a radiotherapeutic agent from the compounds.
