(68)Ga generator integrated system: elution-purification-concentration integration

Abstract

A (68)Ge/(68)Ga generator combined with an automated (68)Ga eluate purification-concentration unit [radioisotope generator integrated system (RADIGIS)], specially designed for (68)Ga processing (RADIGIS-(68)Ga), was developed. The high-stability sorbents of a nanocrystalline structure Zr-Ti ceramic matrix were used for immobilizing the (68)Ge, and the (68)Ga was eluted from the sorbent column with 3.5 mL 0.05-0.1 M HCl solution following an optimized (68)Ga-elution schedule. The (68)Ge breakthrough <10(-3)% and no (68)Ge zone spreading/drift found in PET imaging of the (68)Ga generator column prove the excellent performance of the sorbents. (68)Ga eluate was purified on a small column of salt-form ion exchange resin using an aqueous alcohol solution mixture of hydrochloric and ascorbic acids, and halide salts. An alkali solution was used for stripping (68)Ga from the ion exchange resin column to obtain a purified (68)Ga solution, which is conditioned with acidic solution to obtain a final (68)Ga product in either 0.75 mL 0.5 M NaCl solution of pH 3-4 or 0.5 M sodium acetate or citrate solution of pH 5. The (68)Ge content in purified (68)Ga solution was <10(-6)%. An insignificant metallic contamination including (68)Zn found in the (68)Ga solution and its alkalinity-acidity were evaluated with respect to (68)Ga radiolabeling efficacy for DOTATATE and DOTATOC ligands. Quality control protocols were also developed to evaluate the quality of (68)Ga solution.