Optimization of the Use of the DOTATATE Kit Manufactured by the Thailand Institute of Nuclear Technology Using a SiO<inf>2</inf>-based ⁶⁸Ge/⁶⁸Ga Generator

Abstract

Objective: The presence of somatostatin receptors on neuroendocrine tumours enables 68Ga-DOTATATE to precisely detect lesion localization and staging. Thailand Institute of Nuclear Technology (TINT) recently developed a DOTATATE kit for labelling with Ga-68, which is compatible with a TiO2-based 68Ge/68Ga generator eluted with 0.1 M HCl, but presents a discrepancy with other types of 68Ge/68Ga generators. This research aimed to optimize a radiolabelling method using TINT’s kit with a SiO2-based 68Ge/68Ga generator eluting Ga-68 in 0.05 M HCl. Additionally, a quality control protocol was developed to ensure the formulation’s efficacy and reliability in compliance with the 10th edition of the European Pharmacopoeia. Material and Methods: The SiO2-based 68Ge/68Ga generator was eluted with 2–4 ml of 0.05 M HCl, added into a lyophilized kit, heated in a dried-block heater at 100 ºC for 15 min, cooled down at room temperature, and finally purified using Sep-Pak C18 cartridge. The radiochemical purity was determined by radio thin-layer chromatography and the radioactivity was measured by a gamma well counter. Reproducibility and stability tests were conducted three times. Results: Employing 4 ml of eluted material, comprising the second and fifth millilitres of 68GaCl3, provided a radiochemical purity (RCP) exceeding 95% after purification. Also, 68Ga-DOTATATE remained stable in refrigerator for at least 4 half-lives. Conclusion: TINT’s DOTATATE kit can be successfully labelled with a SiO2-based 68Ge/68Ga generator, providing 68Ga-DOTATATE with an RCP > 95% for at least 4 half-lives when stored in refrigerator after production. This radiolabelling procedure is suitable for routine clinical application.