The favorable decay properties of 43Sc and 44Sc for PET make them promising candidates for future applications in nuclear medicine. An advantage 43Sc (T1/2 = 3.89 h, Eβ+ av = 476 keV [88%]) exhibits over 44Sc, however, is the absence of co-emitted high energy γ-rays. While the production and application of 44Sc has been comprehensively discussed, research concerning 43Sc is still in its infancy. This study aimed at developing two different production routes for 43Sc, based on proton irradiation of enriched 46Ti and 43Ca target material. 43Sc was produced via the 46Ti(p,α)43Sc and 43Ca(p,n)43Sc nuclear reactions, yielding activities of up to 225 MBq and 480 MBq, respectively. 43Sc was chemically separated from enriched metallic 46Ti (97.0%) and 43CaCO3 (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% 43Sc were achieved from the irradiation of 46Ti, whereas the product isolated from irradiated 43Ca consisted of 66.2% 43Sc and 33.3% 44Sc. A PET phantom study performed with 43Sc, via both nuclear reactions, revealed slightly improved resolution over 44Sc. In order to assess the chemical purity of the separated 43Sc, radiolabeling experiments were performed with DOTANOC, attaining specific activities of 5–8 MBq/nmol, respectively, with a radiochemical yield of >96%. It was determined that higher 43Sc activities were accessible via the 43Ca production route, with a comparatively less complex target preparation and separation procedure. The product isolated from irradiated 46Ti, however, revealed purer 43Sc with minor radionuclidic impurities. Based on the results obtained herein, the 43Ca route features some advantages (such as higher yields and direct usage of the purchased target material) over the 46Ti path when aiming at 43Sc production on a routine basis.

中文翻译：

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用于放射性药物目的的 43Sc 的生产和分离。

43Sc 和 44Sc 对 PET 的有利衰减特性使其成为未来核医学应用的有希望的候选者。然而，43Sc (T1/2 = 3.89 h, Eβ+ av = 476 keV [88%]) 表现出超过 44Sc 的优势，但是没有共同发射的高能 γ 射线。虽然对44Sc的生产和应用进行了全面讨论，但有关43Sc的研究仍处于起步阶段。本研究旨在开发两种不同的 43Sc 生产路线，基于富集 46Ti 和 43Ca 靶材的质子辐照。43Sc 是通过 46Ti(p,α)43Sc 和 43Ca(p,n)43Sc 核反应产生的，分别产生高达 225 MBq 和 480 MBq 的活度。43Sc 从富集金属 46Ti (97.0%) 和 43CaCO3 (57.9%) 靶材中化学分离，使用萃取色谱法。在这两种情况下，约 90% 的最终活性在 700 μL 的小体积中被洗脱，因此适合直接放射性标记。制备的产品具有高放射性核素纯度，即从46Ti辐照获得98.2%的43Sc，而从辐照43Ca中分离出的产物由66.2%的43Sc和33.3%的44Sc组成。使用 43Sc 通过两种核反应进行的 PET 体模研究显示，分辨率比 44Sc 略有提高。为了评估分离的 43Sc 的化学纯度，用 DOTANOC 进行了放射性标记实验，分别获得了 5-8 MBq/nmol 的比活度，放射化学产率 > 96%。确定通过 43Ca 生产途径可以获得更高的 43Sc 活性，具有相对不太复杂的目标制备和分离程序。然而，从辐照过的 46Ti 中分离出的产品显示出更纯的 43Sc，含有少量放射性核素杂质。根据本文获得的结果，当以常规方式生产 43Sc 时，43Ca 路线与 46Ti 路线相比具有一些优势（例如更高的产量和直接使用购买的靶材）。