Improved titanium-44 purification process for establishing a high apparent molar activity titanium-44/scandium-44 generator.

⁴⁴ Sc-radiopharmaceuticals are gaining more interest but still lack availability. The proof of principle of a ⁴⁴ Ti/ ⁴⁴ Sc generator, which can produce ⁴⁴ Sc daily, has been established but with some limitations and drawbacks. Despite recent advances, separation of ⁴⁴ Ti from massive quantities of scandium target material is still cumbersome. In this work, the improved radiochemical separation of ⁴⁴ Ti from residual scandium target material was carried out by precipitation of Sc with fluoride ions. Furthermore, two approaches were used to set up a high apparent molar activity small-scale generator. The first method relied on extraction chromatography for fine purification using a DGA resin, followed by loading of the purified ⁴⁴ Ti onto a ZR resin column. In the second method, ⁴⁴ Ti was loaded on the ZR resin directly after the precipitation step. This second method was used to set up a generator of 370 kBq and evaluate by radiolabeling. An apparent molar activity of 2 MBq/nmol was obtained for the radiolabeling with DOTA, the most common and suitable chelate for scandium. This result is comparable with previously published data on ^{44   m/44} Sc.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Cathy S. Cutler, Dmitri G. Medvedev reports financial support was provided by US Department of Energy. Sandrine HUCLIER-MARKAI reports financial support was provided by Nantes University. Sandrine Huclier-Markai has patent issued to Sandrine Huclier-Markai and Ferid Haddad. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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