Production and purification of 43Sc and 47Sc from enriched [46Ti]TiO2 and [50Ti]TiO2 targets

The radioscandium isotopes, Sc-43 and Sc-47, compose a promising elementally matched theranostic pair that can be used for the development of imaging and therapeutic radiopharmaceuticals with identical structures. This study aimed to investigate the production of high radionuclidic purity Sc-43 from enriched [Ti-46]TiO2 targets and Sc-47 from enriched [50Ti]TiO2 targets and establish a target recycling technique. Enriched [Ti-46]TiO2 targets were irradiated with 18 MeV protons, and enriched [50Ti]TiO2 targets were bombarded with 24 MeV protons. Sc-43 and Sc-47 were purified using ion chromatography attaining recovery yields of 91.7 +/- 7.4% and 89.9 +/- 3.9%, respectively. The average radionuclidic purity for Sc-43 was 98.8 +/- 0.3% and for Sc-47 91.5 +/- 0.6%, while the average recovery of enriched titanium target material was 96 +/- 4.0%. The highest apparent molar activity for [Sc-43]Sc-DOTA was 23.2 GBq/ mu mol and 3.39 GBq/mu mol for [Sc-47]Sc-DOTA. This work demonstrates the feasibility of using enriched recycled [Ti-46]TiO2 and [50Ti]TiO2 targets to produce high purity Sc-43 and Sc-47 as an elementally matched theranostic isotope pair.