68Ga radiolabeling and quality control in a small-scale radiopharmacy- working amidst constraints in developing countries

Objectives There has been an interest in the clinical applications of Ga68 radiopharmaceutical PET imaging with the wide availability of in house 68Ge/68Ga generator and Ga68 labelled radiotracers finding application in routine clinical practice coupled with the ease of in house elution and relatively simple radiolabelling methods. The major requirements for setting up a basic Ga68 radiopharmacy involve investment in hot cells, a synthesis module and quality control equipment (e.g. gas chromatography (GC), high-performance liquid chromatography (HPLC) and absorption spectrometry). These prerequisites are more easily met in large scale well-equiped radiopharmacy departments but less often in conventional small-scale radiopharmacies. Our aim was to establish a dedicated set up at our institution for production of Ga68 radiolabeled agents in compliance with the ‘EANM guideline on the small-scale ‘in-house’ preparation of radiopharmaceuticals which are not kit procedures (cGRPP)’ (1) at our in house radiopharmacy, however within the space and budget constraints of a small scale setup.

Methods We attempted validation of thin-layer chromatography (ITLC) method to replace HPLC as a routine modality for examining radiochemical purity during quality control of radioloabeled Ga68 DOTANOC for 10 cycles before clinical use.

Results Using a labelling module by ITG, a 68Ga-DOTA-NOC labelling procedure was set up as per the prescribed radiolabeling guidelines and specifications. We attempted quality control of the labeled product for 10 labeling cycles before clinical use and found that the ITLC method for detecting unbound Ga68 showed consistently high radiolabeling efficiency (>95%) with similar results seen on HPLC with a high positive correlation (correlation coefficient r=0.96) for each batch of labeled radiopharmaceuticals processed parallelly. All other quality assurance requirements were followed as per the cGRPP guidelines.

Conclusions We suggest that ITLC may be used as replacement for costly HPLC equipment as a feasible approach for QC in small-scale radiopharmacies to minimise technical, spatial and financial constraints which shall help to increase the availability of 68Ga radiopharmaceuticals.