Ga-AATS for Human Based on Biodistribution Data in Rats

Introduction Gallium-67 ( 67 Ga) has been used as a radionuclide for imaging a variety of solid tumors since 1969. Since then use of various gallium-based radiotracers has been reported. Recently, 67 Ga-labeled acetylacetate bis(thiosemicarbazones) ( 67 Ga-AATS) complex with significant tumor accumulation and fast blood clearance has been employed. Materials and Methods In this study, the absorbed dose of 67 Ga-AATS in each human organ was evaluated and compared with 67 Gacitrate as the most commonly used form of 67 Ga in nuclear medicine. 67 Ga was produced via 68 Zn(p,2n) 67 Ga reaction at 30 MeV cyclotron. Moreover, 67 Ga-AATS was produced by adding 50 μl of AATS to absolute ethanol (1 mg/ml) in a gallium-containing vial at 80-90 ° C. The absorbed dose of each human organ was calculated, using RADAR method, based on biodistribution data in Wistar rats. Results According to the results, 67 Ga-AATS was produced with radionuclidic and radiochemical purity higher than 99% and 93%, respectively. The highest absorbed dose was reported in the bone surface (0.401 mGy/MBq), whereas the whole-body absorbed dose was 0.092 mGy/MBq. Conclusion The absorbed dose of each human organ was comparable with the absorbed dose received by each organ after 67 Ga-citrate injection. Considering this interesting finding and the significant tumor uptake, it seems that 67 Ga-AATS can be used as an appropriate SPECT tracer.