This invention provides novel radiopharmaceuticals which are useful as imaging agents for the diagnosis of cardiovascular disorders, infectious diseases and cancer. The radiopharmaceuticals are comprised of phosphine or arsine ligated technetium-99m labelled hydrazine or diazino modified biologically active molecules that selectively localize at sites of disease and thus allow an image to be obtained of the loci using gamma scintigraphy. This invention also provides methods for using the radiopharmaceuticals and kits comprising radiopharmaceutical precursors. The radiopharmaceuticals of this invention havee the structure: [(Q) d' L n -C h' ] x -M t (A L1 ) y (A L2 ) z wherein the variables are as defined therein.