Preliminary Dosimetry Study of 67Ga-AATS for Human Based on Biodistribution Data in Rats

Introduction: gallium-67 (67ga) 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, 67ga-labeled acetylacetate bis(thiosemicarbazones) (67ga-aats) complex with significant tumor accumulation and fast blood clearance has been employed. materials and methods: in this study, the absorbed dose of 67ga-aats in each human organ was evaluated and compared with 67ga-citrate as the most commonly used form of 67ga in nuclear medicine. 67ga was produced via 68zn(p,2n)67ga reaction at 30 mev cyclotron. moreover, 67ga-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, 67ga-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 67ga-citrate injection. considering this interesting finding and the significant tumor uptake, it seems that 67ga-aats can be used as an appropriate spect tracer.