Purpose Development of a gallium-68-labeled renal tracer can be a good substitute for Tc-99m, a known SPECT tracer. In this study, effort was made to develop 6 8 Gaethylenecysteamine cysteine ( 68 Ga-ECC). Methods Ga-ECC was prepared using generator-based 68 GaCl 3 and ethylenecysteamine cysteine (ECC) at optimized conditions. Stability of the complex was checked in human serum followed by partition coefficient determination of the tracer. The biodistribution of the tracer in rats was studied using tissue counting and PET/CT imaging up to 120 min. Results Ga-ECC was prepared at optimized conditions in 15 min at 90°C (radiochemical purity ≈97±0.88 % ITLC, >99 % HPLC, specific activity: 210±5 GBq/mM).68 Ga-ECC was a water-soluble complex based on partition coefficient data (log P; −1.378) and was stable in the presence of human serum for 2 h at 37°C. The biodistribution of the tracer demonstrated high kidney excretion of the tracer in 10-20 min. The SUV max ratios of the liver to left kidney were 0.38 and 0.39 for 30 and 90 min, respectively, indicating high kidney uptake. Conclusion Initial biodistribution results showed significant kidney and urinary excretion of the tracer comparable to that of the homologous 99m Tc compound. The complex could be a possible PET kidney imaging agent with a fast imaging time.

In this work development of 68 Ga-ethyl cysteinate dimer ( 68 Ga-ECD) a 68 Ga tracer for possible cerebral blood flow based on 99m Tc ECD homolog is reported. 68 Ga-ECD was prepared using generator-based 68 GaCl 3 and ECD at optimized conditions. Quality control, stability, partition co-efficient and the biodistribution of the tracer (by tissue counting and PET/CT in rats) was studied. Significant metabolism of the lipophilic tracer into water soluble metabolite(s) led to urinary excretion of the tracer, un-comparable to that of homologous 99m Tc-compound. Cardiac uptake of the complex suggests formation of a possible lipophil cationic complex and/or metabolite.