68Ga-autoclabeling of DOTA-TATE and DOTA-NOC

Introduction: A new method combining (68)Ga-labeling and steam sterilization, here called autoclabeling, has been evaluated for two somatostatin receptor binding tracers used for positron emission tomography (PET) imaging of neuroendocrine tumors; DOTA-TATE and -NOC.

Methods: The two peptides DOTA-TATE and -NOC were labeled with (68)Ga by heating for 15 min at 121°C in the presence of acetate buffer at pH 4.3. The product solutions were tested for sterility, presence of endotoxins, degradation of peptide and osmolality.

Results: Complete incorporation of (68)Ga was obtained after the autoclabeling reaction and no degradation of the peptides was observed. Sterility was verified and the presence of endotoxins was well within Ph. Eur limits (175IU/maximum injected volume).

Conclusions: The autoclabeling method provides a convenient procedure for (68)Ga-labeling by combining the labeling reaction and steam sterilization into one single step.