Manual labeling of ⁶⁸Ga radiopharmaceuticals and evaluation of radiochemical purity by two different methods

⁶⁸Ge-⁶⁸Ga generator produces positron emitting isotope ⁶⁸Ga from a source of decaying ⁶⁸Ge. ⁶⁸Ga is routinely labeled to the pharmaceutical molecules DOTANOC for neuroendocrine tumor (NET) and prostate-specific membrane antigen (PSMA) for prostate cancer. Radiochemical purity (RCP) was evaluated by paper chromatography technique. ITLC-SG paper was used as a stationary phase and aetonitrile:water (1:1) and ammonium acetate:methanol as a mobile phase. Sep-Pak plus cartridges are used for filtration if radiopharmaceutical (RP) fails, by passing the radiolabeled complex through the cartridge in which the free gallium stays in the filter. The study aims to check the labeling efficiency and RCP of gallium RPs by the manual method. In our experience, calculated RCP% of Ga RPs using both acetonitrile:water (1:1) and ammonium acetate:methanol as mobile phase showed a more accurate representation of RCP for prepared products. If both the quality control tests for a preparation were more than 90%, then only the RP should be injected to patient. Ammonium acetate and methanol has a good accuracy to calculate the %RCP compared to acetonitrile and water as a mobile phase. The radiation exposure measured in a pocket dosimeter after the Ga RP preparation was found to be 2–3 μS, which is within the ALARA limit