Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada.
Edmonton Radiopharmaceutical Center, Alberta Health Services, 11560 University Ave, Edmonton, AB, T6G 1Z2, Canada.
Sci Rep. 2020 Dec 17;10(1):22203. doi: 10.1038/s41598-020-79198-x.
This study reports the high-yield production of a novel La theranostic pair at a 22 MeV proton beam energy as an attractive alternative to the recently introduced La pair, demonstrating over an order of magnitude production increase of La (231 ± 8 MBq La and 166 ± 5 MBq La at End of Bombardment (EOB)) compared to 11.9 MeV production of La (0.82 ± 0.06 MBq La and 19.0 ± 1.2 MBq La) for 500 µA·min irradiations. A new sealed solid cyclotron target is introduced, which is fast to assemble, easy to handle, storable, and contains reusable components. Radiolabeling with macrocyclic chelators DOTA and macropa achieved full incorporation, with respective apparent La molar activites of 33 ± 5 GBq/µmol and 30 ± 4 GBq/µmol. PET centers with access to a 22 MeV capable cyclotron could produce clinically-relevant doses of La, via Ba irradiation, as a standalone theranostic agent for PET imaging and Auger electron therapy. With lower positron energies and less energetic and abundant gamma rays than Ga, Sc and La, La appears to be an attractive radiometal candidate for PET applications requiring a higher scanning resolution, a relatively long isotopic half-life, ease of handling, and a low patient dose.
本研究报告了在 22 MeV 质子束能量下高产新型镧治疗偶联物，这是对最近引入的镧偶联物的有吸引力的替代方案，与 11.9 MeV 下的镧（0.82 ± 0.06 MBq La 和 19.0 ± 1.2 MBq La）相比，产量增加了一个数量级以上，500 µA·min 辐照时，镧（231 ± 8 MBq La 和 166 ± 5 MBq La）的产量更高。引入了一种新型密封固体回旋加速器靶，该靶易于组装、操作方便、可储存且包含可重复使用的组件。用大环螯合剂 DOTA 和大环螯合剂 macropa 进行放射性标记，实现了完全掺入，相应的镧表观摩尔活度分别为 33 ± 5 GBq/µmol 和 30 ± 4 GBq/µmol。具有 22 MeV 能力回旋加速器的 PET 中心可以通过 Ba 辐照生产临床相关剂量的 La，作为单独的 PET 成像和俄歇电子治疗的治疗偶联物。与 Ga、Sc 和 La 相比，镧具有更低的正电子能量和更少的高能且丰富的伽马射线，因此对于需要更高扫描分辨率、相对较长的同位素半衰期、易于操作和低患者剂量的 PET 应用，镧似乎是一种有吸引力的放射性金属候选物。
