99mTc-2GAM: A tracer for renal imaging

We propose a renal imaging agent, the 99m Tc complex of the bidentate- N ,S chelate N -(mercaptoacetyl) glycine ( 99m Tc-2GAM), with the imaging characteristics of 99m Tc-DMSA but a faster kidney uptake; chemical evidence supports the formulation of 99m Tc-2GAM as [Tc V (O)(GAM) 2 ] − . After biodistribution and toxicity studies in animals, 99m Tc-2GAM was evaluated in five normal volunteers. 99m Tc-2GAM is rapidly cleared from the blood (t12 = 9 min) and 50% of the ID is excreted in the urine in the first 2 h. Dynamic data show a rapid renal uptake that increases up to 1 h with no significant wash-out between 1 and 8 h. The uptake in each kidney ranges from 11.3% to 20.7% ID. Low, stable liver uptake is observed. No significant activity is detected in other organs. We showed no differences between 99m Tc-2GAM and 99m Tc-DMSA compared in three patients with unilateral kidney disease. We conclude that 99m Tc-2GAM has good practical and dosimetric features for renal imaging.