Evaluation of the Efficacy and Safety of the ITM 68Ge/68Ga Generator After its Recommended Shelf-life

Abstract

Objective: 68Ga can be routinely produced by a 68Ge/68Ga generator without the need for a cyclotron. It is recommended to replace the 68Ge/68Ga generator after 250 elutions or 12 months of shelf-life whichever endpoint is reached first. However, a 68Ge/68Ga generator that has gone past its recommended lifespan can still be further used as a 68Ga source for 68Ga-labeled radiopharmaceuticals for use in animal experiments. To ensure the quality of 68Ga eluates, we aimed to evaluate the efficacy and safety of the ITM (Isotope Technologies München) 68Ge/68Ga generator in our institute after its recommended shelf-life. Materials and Methods: A 21-month-old ITM 68Ge/68Ga generator was eluted using 4.0 ml of 0.05 M HCl. The 68Ga elution yields were calculated, and 68Ge breakthrough was measured at least 48 h after elution in an aliquot amount using a multichannel analyzer (MCA) with a high-purity germanium probe. Metal impurities in the 68Ga eluates were analyzed by ICP-MS. Results: The elution yield of 68Ga was 35.2 ± 8.1%; n = 5 (decay corrected). 68Ge breakthrough from the ITM 68Ge/68Ga generator was below the detectable level. The average amounts of the metallic ions 57Fe, 66Zn, 203Pb, 60Ni, and 63Cu were 18.60, 9.86, 2.42, 0.52, and 0.47 µg/GBq, respectively. Conclusion: The ITM 68Ge/68Ga generator demonstrated consistent and reliable 68Ga elution profiles with an absence of either 68Ge breakthrough or other metal contaminants in the eluent samples as verified by the manufacturer. The use of the ITM 68Ge/68Ga generator could be extended past its recommended shelf-life to prepare 68Ga radiopharmaceuticals that are considered safe and suitable for use in animal experimentation and other applications.