en Radiobiology Radiobiology تحقيق بديع Original Research <div style="text-align: justify;">Background: In recent years, Gallium-68 citrate has become known as an alternative radioisotope in nuclear medicine. As for its influences, ⁶⁸Ga-based tracers have already been proposed as agents for positron emission tomography. In this research, the values of human absorbed dose for ⁶⁸Ga-citrate and ⁶⁷Ga-citrate were estimated using the medical internal radiation dose method based on biodistribution data in rats. Materials and Methods: ⁶⁸Ga/⁶⁷Ga-citrate was prepared from eluted ⁶⁸Ga/⁶⁷Ga-Cl₃ &shy;and sodium citrate under multiple reaction forms. The biodistribution of ⁶⁸Ga/⁶⁷Ga&ndash;citrate 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&rsquo; data. Results: The results of estimating the human absorbed dose illustrate that ⁶⁸Ga-citrate caused a much lower human absorbed dose compared with ⁶⁷Ga-citrate. Conclusion: According to the results, it may be concluded that ⁶⁸Ga-citrate, despite the better quality of PET imaging, is much safer in terms of absorption dose compared with ⁶⁷Ga-&shy;citrate, and from this point of view, it is a more appropriate agent for imaging applications.</div> &nbsp; Internal radiation dose, MIRD, 68-Ga-citrate, 67-Ga-citrate. 151 156 http://ijrr.com/browse.php?a_code=A-10-2188-75&slc_lang=en&sid=1 F. Habibi 7900319475328460020850 7900319475328460020850 No Shiraz University, Nuclear Engineering Department, Shiraz, Iran R. Faghihi 7900319475328460020851 7900319475328460020851 No Shiraz University, Nuclear Engineering Department, Shiraz, Iran S. Zolghadri 7900319475328460020852 7900319475328460020852 No Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran H. Yousefnia hyousefnia@aeoi.org.ir 7900319475328460020853 7900319475328460020853 Yes Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran S. Sina 7900319475328460020854 7900319475328460020854 No Shiraz University, Radiation Research Center, Shiraz, Iran F. i Mohammadpour-Ghaz 7900319475328460020855 7900319475328460020855 No Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran