Fully Automated ⁶⁸Ga-Labeling and Purification of Macroaggregated Albumin Particles for Lung Perfusion PET Imaging

Lung PET/CT is a promising imaging modality for regional lung function assessment. Our aim was to develop and validate a fast, simple, and fully automated GMP compliant [⁶⁸Ga]Ga-MAA labeling procedure, using a commercially available [^99mTc]Tc-MAA kit, a direct gallium-68 eluate and including a purification of the [⁶⁸Ga]Ga-MAA. Method: The synthesis parameters (pH, heating temperature) were manually determined. Automated ⁶⁸Ga-labeling of MAA was then developed on a miniAIO (Trasis®, Ans, Belgium) module. An innovative automated process was developed for the purification. The process was then optimized and adapted to automate both the [⁶⁸Ga]Ga-MAA synthesis and the isolation of gallium-68 eluate required for the pulmonary ventilation PET/CT. Results: The 15-min process demonstrated high reliability and reproducibility, with high synthesis yield (>95 %). Mean [⁶⁸Ga]Ga-MAA radiochemical purity was 99 % ± 0.6 %. The ⁶⁸Ga-labeled MAA particles size and morphology remained unchanged. Conclusion: A fast, user friendly, and fully automated process to produce GMP [⁶⁸Ga]Ga-MAA for clinical use was developed. This automated process combining the advantages of using a non-modified MAA commercial kit, a gallium-68 eluate without pre-purification and an efficient final purification of the [⁶⁸Ga]Ga-MAA may facilitate the implementation of lung PET/CT imaging in nuclear medicine departments.