Preparation of [68Ga]PSMA-11 for PET–CT imaging using a manual synthesis module and organic matrix based 68Ge/68Ga generator

Introduction[68Ga]PSMA-11 is a relatively recently introduced radiopharmaceutical for PET–CT imaging of prostate cancer patients. The availability of 68Ge/68Ga generator and PSMA-11 ligand from commercial sources is facilitating the production of the radiopharmaceutical in-house. This paper describes our experience on the preparation of ~ 200 batches of [68Ga]PSMA-11 for conducting PET–CT imaging in patients suspected/suffering from prostate cancer.MethodsThe radiosynthesis of [68Ga]PSMA-11 was done in a hospital based nuclear medicine department using 68Ge/68Ga generator and a manual synthesis module, both supplied by Isotope Technologies Garching (ITG), Germany. The production involved the reaction of 5 μg (5.3 nmol) of PSMA-11 ligand in 1 ml of 0.25 M sodium acetate buffer with 4 ml of 68GaCl3 in 0.05 M HCl for 5 min at 105 °C; followed by purification in a C18 cartridge and collection through a 0.22 μm pore size filter.ResultsThe radiochemical yields obtained were consistently high, 93.19% ± 3.76%, and there was hardly any batch failure. The radiochemical purity of the product was > 99% and the product was stable for over 2 h; however it was used in patients immediately after preparation. About 200 batches of [68Ga]PSMA-11 were prepared during the period and more than 300 patients received the tracer during the 14 months of study. No adverse reaction was observed in any of the patients and the image qualities were consistent with literature reports.Conclusion[68Ga]PSMA-11 with high radiochemical and radionuclidic purity is conveniently prepared by using a 68Ge/68Ga generator and manual synthesis module. The radiochemical yields are very high; and activity sufficient for 3–4 patients can be prepared in a single batch; multiple batches can be done on the same day and when needed after a gap of 1.5–2 h.