A radiopharmaceutical core of chelating agent DTPA (diethylenetriaminepentaacetic acid) complexed with the gamma-emitting radionuclide technetium Tc 99m with radioimaging application. Tc-99m-DTPA has been utilized as a radiotracer, when conjugated to tissue specific molecules, in a wide variety of nuclear imaging studies, including brain, lung, and renal function studies.