Collins S M, Köster U, Robinson A P, Ivanov P, Cocolios T E, Russell B, Fenwick A J, Bernerd C, Stegemann S, Johnston K, Gerami A M, Chrysalidis K, Mohamud H, Ramirez N, Bhaisare A, Mewburn-Crook J, Cullen D M, Pietras B, Pells S, Dockx K, Stucki N, Regan P H
National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK; School of Mathematics and Physics, University of Surrey, Guildford, GU2 7XH, UK.
Institut Laue-Langevin, 38042, Grenoble, France.
Appl Radiat Isot. 2023 Dec;202:111044. doi: 10.1016/j.apradiso.2023.111044. Epub 2023 Sep 27.
Terbium-152 is one of four terbium radioisotopes that together form a potential theranostic toolbox for the personalised treatment of tumours. As Tb decay by positron emission it can be utilised for diagnostics by positron emission tomography. For use in radiopharmaceuticals and for activity measurements by an activity calibrator a high radionuclide purity of the material and an accurate and precise knowledge of the half-life is required. Mass-separation and radiochemical purification provide a production route of high purity Tb. In the current work, two mass-separated samples from the CERN-ISOLDE facility have been assayed at the National Physical Laboratory to investigate the radionuclide purity. These samples have been used to perform four measurements of the half-life by three independent techniques: high-purity germanium gamma-ray spectrometry, ionisation chamber measurements and liquid scintillation counting. From the four measurement campaigns a half-life of 17.8784(95) h has been determined. The reported half-life shows a significant difference to the currently evaluated half-life (ζ-score = 3.77), with a relative difference of 2.2 % and an order of magnitude improvement in the precision. This work also shows that under controlled conditions the combination of mass-separation and radiochemical separation can provide high-purity Tb.
铽 - 152是四种铽放射性同位素之一，它们共同构成了一个潜在的肿瘤个性化治疗诊疗工具箱。由于铽通过正电子发射衰变，它可用于正电子发射断层扫描诊断。用于放射性药物以及通过活度校准器进行活度测量时，需要材料具有高放射性核素纯度以及对半衰期有准确精确的了解。质量分离和放射化学纯化提供了一种生产高纯度铽的途径。在当前工作中，来自欧洲核子研究中心 - 同位素分离器（CERN - ISOLDE）设施的两个经过质量分离的样品已在国家物理实验室进行分析，以研究放射性核素纯度。这些样品已用于通过三种独立技术进行四次半衰期测量：高纯锗γ射线能谱法、电离室测量和液体闪烁计数法。通过这四次测量活动，确定半衰期为17.8784(95)小时。报告的半衰期与当前评估的半衰期有显著差异（ζ分数 = 3.77），相对差异为2.2%，精度提高了一个数量级。这项工作还表明，在受控条件下，质量分离和放射化学分离相结合可提供高纯度铽。
