Performance and long-term consistency of five Galliform 68Ge/68Ga generators used for clinical Ga-68 preparations over a 4 year period.

Abstract

Gallium-68 is a positron emitter for PET applications that can be produced without cyclotron by a germanium (Ge-68) chloride/gallium (Ga-68) chloride generator. Short half-life (67.71 min) of Ga-68, matching pharmacokinetic properties of small biomolecules, facilitates isotope utilization in compounding radiopharmaceuticals for PET imaging. The increasing cost of good manufacturing practice-compliant generators has strengthened the need for radionuclide efficient use by planning specific radiopharmaceutical sessions during the week, careful maintenance of the generator and achievement of high labeling yield and radiochemical purity (RCP) of the radiolabeled molecules. The aim of this study was to evaluate the annual performance of five consecutive 68Ge/68Ga generators used for small-scale preparations of 68Ga-radiopharmaceuticals. To assess the long-term efficiency of isotope production we measured the weekly elution yield. To assess process efficiency we measured elution yield, labeling yield and RCP of four radiopharmaceutical preparations (68Ga-DOTATOC, 68Ga-PSMA-HBED-CC, 68Ga-PENTIXAFOR and 68Ga-DOTATATE). The annual mean elution yield of the generators was 74.7%, higher than that indicated by the manufacturer, and it never went below 65%. The Ge-68 level in the final products was under the detection limits in all the produced batches (mean value 0.0000048%). The RCP of radiopharmaceuticals determined by high-performance liquid chromatography was 98 ± 0.22%. The mean yield of radiolabelling was 64.68, 68.71, 57 and 63.68% for 68Ga-DOTATOC, 68Ga-PSMA-HBED-CC, 68GaPENTIXAFOR and 68Ga-DOTATATE. The ability to prepare in the hospital radiopharmacy high-purity and pharmaceutically acceptable 68Ga-radiolabeled probes on a routine basis facilitates patient access to precision imaging for clinical and research aims.