99mTc-EC: A new renal functional imaging agent

The biological behavior of Technetium-99m-L,L-Ethylenedicysteine (Tc-99m-EC)was compared with that of Technetium-99m-Mercaftoacetyltriglycine (Tc-99m-MAG3) and Iodine-131-hippuran (1131-OIH) in mice and rabbits. Tc-99m-EC showed a more rapid urinary excretion and less retention in kidney, liver, intestines and blood in comparison to Tc-99m-MAG3 and I-131-OIH. Urinary excretion decreased after probenecid treatment, indicating active tubular transport. In human bodies, the renal scintigraphy with Tc-99m-EC, Tc-99m-MAG3 and Tc-99m-DTPA were comparable. The promising results of the animal and human studies suggest that Tc-99m-EC may be a useful alternative to Tc-99m-MAG3 and I-131-OIH for renal functional studies.