PRELIMINARY EVALUATION OF Tc-99m MERCAPTOACETYLTRIGLYCINE, A NEW Tc-99m RENAL FUNCTION AGENT, IN VOLUNTEERS

• Published in: Clinical nuclear medicine 1984-09, Vol.9 (9S Suppl), p.45-45
• Main Authors: Taylor, A, Fritzberg, A R, Eshima, D, Christian, P E, Kashina, S, Johnson, D
• Format: Article
• Language: English
• ISSN: 0363-9762; 1536-0229
• DOI: 10.1097/00003072-198409001-00062

Complexes of Tc-99m based on derivatives of the diamide disulfur ligand, N,N'-bis(mercaptoacetyl)ethyldiamine have shown promise in clinical studies as a Tc-99m replacement for I-131 hippuran (OIH) for renal function studies. However, problems of specificity, the rate of renal excretion, and differences in behavior based on stereochemistry have caused them to be biologically inferior to OIH. An N3S ligand, Tc-99m mercaptoacetyltriglycine (MAG3) has recently been synthesized. The ligand avoids the problem of stereo isomers. We have recently completed studies in normal volunteers comparing the renal excretion, blood clearance, and leading edge transit time of Tc-99m MAG3 and OIH. Blood clearance data were obtained in 8 of 10 volunteers; in all 8, Tc-99m MAG3 was cleared more rapidly than OIH with a mean clearance of 1.08 L/min/1.72m for the Tc-99m MAG3 and .80 for the OIH. Thirty minute urine collections were obtained in 8 of the 10 volunteers. In all cases there was greater excretion of the Tc-99m MAG3 than OIH; Tc-99m MAG3 excretion at 30 minutes ranged from 101% to 122% of the OIH excretion. Approximately 75% of the injected dose of the Tc-99m MAG3 was excreted by 30 min and excretion was virtually complete at 3 hours. The leading edge transit time was also calculated in 7 of 10 volunteers. In all cases the leading edge transit time of the Tc-99m MAG3 was equal to or less than that of OIH with mean time of 177 seconds for the Tc-99m MAG3 compared to 209 seconds for OIH. Based on these preliminary results further evaluation of the Tc-99m MAG3 appears to be justified.