Fast and simple preparation of ⁶⁸Ga-citrate for routine clinical PET

The imaging of infectious and inflammatory diseases using gallium-67 (⁶⁷Ga) citrate scintigraphy has been a well-established diagnostic tool for decades. In recent times, interest has focused on PET using the short-lived positron emitting radioisotope ⁶⁸Ga. ⁶⁸Ga is not only more readily available, it also provides better quality images whose high resolution permits quantitative analyses, thus improving the management of patients suffering from infections or inflammation. The purpose of our study was to develop a fast and reliable synthesis protocol for the preparation of ⁶⁸Ga citrate under good manufacturing practice aspects without the use of organic solvents. A commercially available synthesis module was used to perform 10 syntheses with an average yield of 768 ± 31 MBq (mean ± SD) within 10 min; 92.04 ± 1.23% of the radioactivity was located in the product vial, and the rest on the cation exchange cartridge (7.48 ± 1.23%) and in the waste vial (0.47 ± 0.28%). The radiochemical purity of the product determined by instant thin-layer chromatography was greater than 99%. The products have been proven to be sterile and pyrogen-free. Variations were made in several critical synthesis parameters, and the results are presented herein. By eliminating the use of organic solvents, the previously required quality control testing of the final product by gas chromatography can be abandoned. This novel, high-yielding method allows for a more efficient synthesis of ⁶⁸Ga citrate with both shorter production time and high radiochemical purity.