Estimation of human absorbed dose of 68-Ga-Citrate based on biodistribution data in rats: Comparison with 67-Ga-Citrate

Abstract

Background:In recent years, Gallium-68 citrate has become known as an alternative radioisotope in nuclear medicine. As for its influences, 68 Ga-based tracers have already been proposed as agents for positron emission tomography. In this research, the values of human absorbed dose for 68 Ga-citrate and 67 Ga-citrate were estimated using the medical internal radiation dose method based on biodistribution data in rats. Materials and Methods: 68 Ga/ 67 Ga-citrate was prepared from eluted 68 Ga/ 67 Ga-Cl 3 and sodium citrate under multiple reaction forms. The biodistribution of 68 Ga/ 67 Gacitrate radiolabeled compounds was investigated by dissection of five male rats at specific times after injection. The organs of the rats were removed and counted. Percentage of injected dose per gram was determined for each rat organ and the human absorbed dose was extrapolated using the rats' data. Results: The results of estimating the human absorbed dose illustrate that 68 Ga-citrate caused a much lower human absorbed dose compared with 67 Ga-citrate. Conclusion: According to the results, it may be concluded that 68 Ga-citrate, despite the better quality of PET imaging, is much safer in terms of absorption dose compared with 67 Ga-citrate, and from this point of view, it is a more appropriate agent for imaging applications.