Preparation of Tc 99m-Sn-thioglycolic acid-dl-isoleucine (Tc-99m-TGA-ILEU) complex and its comparison with Tl 201-chloride for myocardial imaging.

Dl-lsoleucine was complexed with Thioglycolic acid in the presence of Stannous ions to label with TC99m-Pertechnetate. Percentage labeling was determined by paper chromatography. Preparations of more than 95% labeled with Tc99m were injected to rabbits for imaging and tissue distribution studies. Tc99m.TGA.l LEU complex was investigated as a myocardial imaging agent with respect to its kinetics and its percent organ uptake. As compared with TI 201, Tc99m. TGA-ILEU complex shows higher heart to lung ratio and higher liver uptake. At the time of peak myocardial uptake, the mean heart uptake of TI 201 was 3.9% in rabbit compared with 3.3% for Tc99m.TGA. I LEU. At 2 hour post-injection TI 201 was found 1.9%andTc99m.TGA.ILEU 1.5%. The kinetics of TC99m.TGA.ILEU complex warrant its further investigation, as a myocardial imaging agent (JPMA36:40,1998).