Dota tate

⁶⁸Ga stock solution was made by rinsing the ⁶⁸Ga generator using 4 mL of 0.05 mol/L hydrochloric acid. The pH value was adjusted to 3.5–4.0 with sodium acetate (0.25 mol/L). Twenty μg of DOTA-TATE (ABX, Germany) was added to the solution and mixed, which was then heated at 95°C for 10 min. The solution was first purified by a Sep-Pak C18 column, and then was filtered using a sterile filter to obtain ⁶⁸Ga-DOTA-TATE injection after washing the column with 50% ethanol solution and saline solution. The radiochemical purity was >99% analyzed by a radioactive high performance liquid chromatography (Radio-HPLC).

The ⁶⁸Ga-DOTA-TATE was prepared on a fully automated system using a standardized labeling sequence. Briefly, a commercially available germanium-68 (⁶⁸Ge)/⁶⁸Ga generator (iThemba Labs, SA) was eluted with 0.6 M hydrochloric acid. Effluent containing the ⁶⁸Ga fraction was transmitted to the PS-H+ cartridge to concentrate and purify ⁶⁸Ga from residual ⁶⁸Ge. The purified ⁶⁸Ga was then eluted with 1.7 mL 5 M sodium chloride into the reaction vial. Twenty-five micrograms DOTA-TATE (ABX, Germany) was dissolved using 3 mL of 1.5 M HEPES buffer solution in the reaction vial. The reaction was performed at 100 °C for 8 minutes. A C-18 light cartridge was used to purify the ⁶⁸Ga-DOTA-TATE. The purified ⁶⁸Ga-DOTA-TATE was eluted with 1 mL ethanol and 1 mL water solutions and passed into a sterile vial. Radiochemical purity was over 95% in all cases, based on high-performance liquid chromatography.