High-Efficiency Cationic Labeling Algorithm of Macroaggregated Albumin with 68Gallium

Purpose The generator product radionuclide gallium-68(Ga-68) is widely used for PET/CT imaging agents and the Ga-68-labeled MAA is an attractive alternative to Tc-99m-labeled MAA. Using a commercially available MAA labeling kit for Tc-99m, we presented a reliable synthesis protocol with a highly efficient, organic solvent-free cationic method in GMP conditions in the Scintomics automated synthesis unit. Methods The labeling process was performed by incubating for 7 min at 90 degrees C in the borax vial containing the generator product (GaCl3)-Ga-68 MAA-HEPES eluted from the PSH+ cartridge with 1.5 mL 5 molar NaCl. Quality control of the final product content was examined, and radiopharmaceutical production was carried out in accordance with GMP guidelines. Results Ga-68 eluted from the generator was obtained in more than 99% radiochemical purity and efficiency. In this case, the labeling efficiency was found to be >99%. When the results of SEM-EDX analysis in the final product were examined, it was determined that most of toxic metals were no appreciable in the product content. Conclusions The radiochemical and chemical purity of the final product allows direct use without purification steps to remove free Ga-68 or other toxic compounds.

Automated summary

The study presented a reliable synthesis protocol for Ga-68-labeled MAA using a commercially available MAA labeling kit for Tc-99m, with a highly efficient, organic solvent-free cationic method. The final product showed >99% radiochemical purity and efficiency, enabling direct use without purification steps to remove free Ga-68 or other toxic compounds.