Preparation of Medical 228Th-224Ra Radionuclide Generator Based on SiO2@TiO2 Microspheres.

224Ra (T1/2 = 3.63 d), an α-emitting radionuclide, holds significant promise in cancer endoradiotherapy. Current 224Ra-related therapy is still scarce because of the lack of reliable radionuclide supply. The 228Th-224Ra radionuclide generator can undoubtedly introduce continuous and sustainable availability of 224Ra for advanced nuclear medicine. However, conventional metal oxides for such radionuclide generators manifest suboptimal adsorption capacities for the parent nuclide, primarily attributable to their limited surface area. In this work, core-shell SiO2@TiO2 microspheres were proposed to develop as column materials for the construction of a 228Th-224Ra generator. SiO2@TiO2 microspheres were well prepared and systematically characterized, which has also been demonstrated to have good adsorption capacity to 228Th and very weak binding affinity toward 224Ra via simulated chemical separation. Upon introducing 228Th-containing solution onto the SiO2@TiO2 functional column, a 228Th-224Ra generator with excellent retention of the parent radionuclide and ideal elution efficiency of daughter radionuclide was obtained. The prepared 228Th-224Ra generator can produce 224Ra with high purity and medical usability in good elution efficiency (98.72%) even over five cycles. To the best of our knowledge, this is the first time that the core-shell mesoporous materials have been applied in a radionuclide generator, which can offer valuable insights for materials chemistry, radiochemical separation, and biological medicine.

Simple and efficient method for producing high radionuclidic purity 111In using enriched 112Cd target.

In this work, a simple and efficient method for producing high radionuclidic purity 111In from an enriched 112Cd target was developed. The enriched 112Cd metal target formed by cyanide-free electroplating was bombarded with protons of 21 MeV in a CS-30 cyclotron. Then, we explored a purification scheme using CL-P204 cation exchange resin wherein 98% of the 111In in the bombarded target could be extracted in less than 1 h. The purified 111In in the form of [111In]In-chloride had a high radionuclidic purity (99.9%) and a low impurity concentration (<1.2 ppm). The yield of 111In via the reaction of 112Cd (p, 2n) 111In was measured to be 222 ± 5 MBq/µA∙h. In addition, a chemical procedure for collecting the unreacted 112Cd at a recovery rate of 96.6% was explored.