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

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