COMPARISON OF THE TC-99M-CYSTEINE COMPLEX AND I-131 HIPPURAN IN BIODISTRIBUTION

This study compares the biological behavior of the Tc-99m-cysteine com plex with I-131-hippuran (I-131-OIH). The potential role of the Tc-99m -cysteine complex as a renal imaging agent has also been evaluated. In addition the biological characteristics, i.e., biodistribution, blood clearance, excretory mechanism and the renal excretion pattern in the presence and absence of the tubular transport inhibitor (2,4-dinitrop henol, probenecid) has been examined. The experimental results reveal that kidneys are the target organ. The blood clearance of these radiop harmaceuticals is rapid, approximately 84% of the injected activity is excreted from the kidneys at 1 hour postinjection. Moreover, the rena l inhibitor obviously depresses the excretory rate of the Tc-99m-cyste ine and I-131-OIH, suggesting that such agents are excreted by renal t ubular secretion. Results presented demonstrate that the Tc-99m-cystei ne is a remarkable renal dynamic imaging agent which is highly promisi ng as a new renal imaging radiopharmaceutical.