Production and separation of (43)Sc for radiopharmaceutical purposes

BACKGROUND: The favorable decay properties of (43)Sc and (44)Sc for PET make them promising candidates for future applications in nuclear medicine. An advantage (43)Sc (T(1/2) = 3.89 h, Eβ(+) (av) = 476 keV [88%]) exhibits over (44)Sc, however, is the absence of co-emitted high energy γ-rays. While the production and application of (44)Sc has been comprehensively discussed, research concerning (43)Sc is still in its infancy. This study aimed at developing two different production routes for (43)Sc, based on proton irradiation of enriched (46)Ti and (43)Ca target material. RESULTS: (43)Sc was produced via the (46)Ti(p,α)(43)Sc and (43)Ca(p,n)(43)Sc nuclear reactions, yielding activities of up to 225 MBq and 480 MBq, respectively. (43)Sc was chemically separated from enriched metallic (46)Ti (97.0%) and (43)CaCO(3) (57.9%) targets, using extraction chromatography. In both cases, ~90% of the final activity was eluted in a small volume of 700 μL, thereby, making it suitable for direct radiolabeling. The prepared products were of high radionuclidic purity, i.e. 98.2% (43)Sc were achieved from the irradiation of (46)Ti, whereas the product isolated from irradiated (43)Ca consisted of 66.2% (43)Sc and 33.3% (44)Sc. A PET phantom study performed with (43)Sc, via both nuclear reactions, revealed slightly improved resolution over (44)Sc. In order to assess the chemical purity of the separated (43)Sc, radiolabeling experiments were performed with DOTANOC, attaining specific activities of 5–8 MBq/nmol, respectively, with a radiochemical yield of >96%. CONCLUSIONS: It was determined that higher (43)Sc activities were accessible via the (43)Ca production route, with a comparatively less complex target preparation and separation procedure. The product isolated from irradiated (46)Ti, however, revealed purer (43)Sc with minor radionuclidic impurities. Based on the results obtained herein, the (43)Ca route features some advantages (such as higher yields and direct usage of the purchased target material) over the (46)Ti path when aiming at (43)Sc production on a routine basis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s41181-017-0033-9) contains supplementary material, which is available to authorized users.