Gallium-68 – A New Opportunity For PET Available From a Long Shelflife Generator – Automation and Applications

Clemens      Decristoforo

Abstract

68Ge/68Ga generators have received tremendous attention in the last years based on the success of 68Ga-labelled Somatostatin analogues for Positron-Emission Tomography (PET), which are today used routinely worldwide. Various commercially available generator types are based on different column matrices including TiO2, SnO2 or organic 68Gechelate coated silica, providing 68Ga as Ga3+ in HCl for radiolabeling procedures. These systems can serve as a stable source of 68Ga for PET applications over periods of more than one year with high yields. A number of methods for post processing of the eluate including fractionation, anion or cation exchange purification have been developed. These methods are particularly important for high specific activity labeling of biomolecules such as peptides ensuring small volumes, low metallic contamination and low 68Ge breakthrough. These systems have been implemented into fully automated modules allowing generator elution, post processing radiolabeling and formulation, complying with high regulatory demands. Quality aspects regarding the clinical use of 68Ga for patient applications including limit of 68Ge content, metal contamination, microbiological safety and radiochemical purity have been addressed. Overall, the establishment of 68Ge/68Ga generator technology together with the development of novel 68Ga-radiopharmaceuticals make 68Ga a most promising radionuclide for PET in the years to come.

Keywords: Gallium-68, 68Ge/68Ga generators, Automation, Post processing, Quality aspects, PET, SPECT, DOTA-SSTA, DOTA peptides