Rapid and automated production of [Ga]gallium chloride and [Ga]Ga-DOTA-TATE on a medical cyclotron.

Introduction: The demand for Gallium-68 (Ga) for labelling PET radiopharmaceuticals has increased over the past few years. Ga is obtained through the decayed parent radionuclide Ge using commercial Ge/Ga generators. The principal limitation of commercial Ge/Ga generators is that only a limited and finite quantity of Ga (<1.85 GBq at start of synthesis) may be accessed. The focus of this study was to investigate the use of a low energy medical cyclotron for the production of greater quantities of Ga and to develop an automated and rapid procedure for processing the product.

Methods: Enriched ZnCl was electrodeposited on a platinum backing using a NHCl (pH 2-4) buffer. The Zn target was irradiated with GE PETtrace 880 at 35 μA and 14.5 and 12.0 MeV beam energy. The irradiated Zn target was purified using octanol resin on an automated system.

Results: Following the described procedure, Ga was obtained in 6.30 ± 0.42 GBq after 8.5 min bombardment and with low radionuclidic impurities (Ga (<0.005%) and Ga (<0.09%)). Purification on a single octanol resin gave 82% recovery with resulting [Ga]GaCl obtained in 3.5 mL of 0.2 M HCl. [Ga]GaCl production from irradiation to final product was <45 min. To highlight the utility of the automated procedure, [Ga]Ga-DOTA-TATE labelling was incorporated to give 1.56 GBq at EOS of the labelled peptide with RCY of >70%.

Conclusions: A straightforward procedure for producing Ga on a low energy medical cyclotron was described. Current efforts are focus on high activity production and radiolabelling using solid target produced Ga.