Rapid and automated production of [68Ga]gallium chloride and [68Ga]Ga-DOTA-TATE on a medical cyclotron

Abstract

Introduction: The demand for Gallium-68 (⁶⁸Ga) for labelling PET radiopharmaceuticals has increased over the past few years. ⁶⁸Ga is obtained through the decayed parent radionuclide ⁶⁸Ge using commercial ⁶⁸Ge/⁶⁸Ga generators. The principal limitation of commercial ⁶⁸Ge/⁶⁸Ga generators is that only a limited and finite quantity of ⁶⁸Ga (<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 ⁶⁸Ga and to develop an automated and rapid procedure for processing the product.

Methods: Enriched ZnCl₂ was electrodeposited on a platinum backing using a NH₄Cl (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, ⁶⁸Ga was obtained in 6.30 ± 0.42 GBq after 8.5 min bombardment and with low radionuclidic impurities (⁶⁶Ga (<0.005%) and ⁶⁷Ga (<0.09%)). Purification on a single octanol resin gave 82% recovery with resulting [⁶⁸Ga]GaCl₃ obtained in 3.5 mL of 0.2 M HCl. [⁶⁸Ga]GaCl₃ production from irradiation to final product was <45 min. To highlight the utility of the automated procedure, [⁶⁸Ga]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 ⁶⁸Ga on a low energy medical cyclotron was described. Current efforts are focus on high activity production and radiolabelling using solid target produced ⁶⁸Ga.

Keywords: Cyclotron; DOTA-TATE; Ga-68; PET; Solid targetry.