An Experimental Generator for Production of High-Purity ²¹²Pb for Use in Radiopharmaceuticals

The feasibility, performance, and radiation safety of an experimental generator were evaluated to efficiently produce ²¹²Pb intended for radiopharmaceuticals. Methods: The generator consisted of a flask with a removable cap containing a source of ²²⁴Ra or ²²⁸Th absorbed on quartz wool. Gaseous ²²⁰Rn emanated from the decaying source, which subsequently decayed to ²¹²Pb, which was adsorbed on the flask's interior surface. The ²¹²Pb was collected by washing the flask with 0.5-1 mL of 0.1 M HCl. Results: The generator collector flask trapped 62%-68% of the ²¹²Pb, of which more than 87% (tested up to 26 MBq) could be harvested. The obtained ²¹²Pb solution had a high purity (>99.98%) and could be used for the preparation of radioconjugates with more than 97% radiochemical purity. Future designs of the generator should aim to further reduce the risk of radon and γ-energy exposure to operators. Conclusion: The presented technology is a promising method for easy and convenient ²¹²Pb production.