A method for high-scale ²²⁵Ac-production for medical application from a massive metallic ²³²Th-target irradiated with 160 MeV-protons is described. The target was made of a metallic Th disk of few mm thickness encapsulated in Nb shell using diffusion welding that provided effective target cooling under an intensive proton beam. Chemical processing started with selectively dissolving Nb and Th in mixtures of HF and HNO₃ of different concentrations. The further chemical treatment included two sequential extractions of Th(IV) with di(2-ethylhexyl)orthophoshoric acid (HDEHP) and purification of Ac by extraction chromatography with DGA-, LN- and TRU-resins. The “end-to-start” technique, where the eluate of the column filled with one sorbent serves as the eluent for the column with next sorbent, was realized. The achieved total chemical yield of ²²⁵Ac was 87% and radionuclidic purity was better than 99.8% (excepting 0.1–0.2% ²²⁷Ac generated at the end of irradiation). The presented method can provide a hundred GBq of ²²⁵Ac in one irradiation run.

中文翻译：

---

用中能质子辐照铌壳中的 232Th 金属靶材生产医用 225Ac

描述了一种从用 160 MeV 质子辐照的大块金属²³² Th 靶材大规模生产医疗应用²²⁵ Ac 的方法。该靶材由几毫米厚的金属Th盘制成，采用扩散焊接封装在铌壳中，在强质子束下提供有效的靶材冷却。化学处理首先将 Nb 和 Th 选择性地溶解在不同浓度的 HF 和 HNO ₃混合物中。进一步的化学处理包括用二(2-乙基己基)正磷酸(HDEHP)连续两次萃取Th( IV )，并通过使用DGA-、LN-和TRU-树脂的萃取色谱法纯化Ac。实现了“端到端”技术，其中填充一种吸附剂的色谱柱的洗脱液充当具有下一种吸附剂的色谱柱的洗脱液。所达到的²²⁵ Ac 总化学收率为 87%，放射性核素纯度优于 99.8%（除了辐照结束时产生的0.1–0.2% ²²⁷ Ac）。所提出的方法可以在一次辐照运行中提供 100 GBq 的^{225 Ac。}