Synthesis, characterization, and biodistribution of oxo complexes of Technetium-99m with biguanide and N1-substituted ligands

We report the synthesis, characterization, and biodistribution of Tc-99m-co mplexes with the bidentate-N,N chelate biguanide (Big) and the N1-substitut ed ligands dimethyl (DMBig), phenyl (PBig), and phenethyl (PEBig). Dynamic gamma camera studies with Tc-99m-Big and Tc-99m-DMSA in rabbits indicated d istinct renal and urinary excretion profiles. Tc-99m-Big was cleared more q uickly than Tc-99m-DMSA, and for the same acquisition times, the contrast i n whole-body images favored Tc-99m-Big. Also, the estimated radiation absor bed doses by kidneys and blood for Tc-99m-DMSA were significantly higher th an for (TC)-T-99m-Big. These preliminary studies show that Tc-99m-Big has f avourable practical and dosimetric features for renal imaging as an alterna tive to Tc-99m-DMSA. NUCL MED BIOL 26;1:79-83, 1999. (C) 1998 Elsevier Scie nce Inc.