Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin; and.
Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin.
J Nucl Med. 2021 Jul 1;62(7):1012-1015. doi: 10.2967/jnumed.120.255794. Epub 2020 Oct 30.
The aim of this work was to explore La as a PET imaging surrogate for Ac using a DOTA-based, tumor-targeting alkylphosphocholine (NM600). La was produced on a biomedical cyclotron. For in vivo experiments, mice bearing 4T1 tumors were administered La-NM600, and PET/CT scans were acquired up to 24 h after injection. After the last time point, the ex vivo tissue distribution was measured to corroborate the in vivo PET data. The ex vivo tissue distribution in mice was determined at 4 and 24 h after injection of Ac-NM600. PET/CT images showed elevated, persistent La-NM600 uptake in the tumor. Low bone accumulation confirmed the in vivo stability of the conjugate. Ex vivo biodistribution studies validated the image-derived quantitative data, and the comparison of the La-NM600 and Ac-NM600 tissue distributions revealed a similar biodistribution for the 2 radiotracers. These findings suggest that La is a suitable imaging surrogate to probe the in vivo biodistribution of Ac radiotherapeutics.
本工作旨在探索使用基于 DOTA 的肿瘤靶向烷基膦胆碱 (NM600) 将镧作为 Ac 的正电子发射断层扫描 (PET) 成像替代物。镧在生物医学回旋加速器上产生。在体内实验中，给荷有 4T1 肿瘤的小鼠注射 La-NM600，并在注射后长达 24 小时进行 PET/CT 扫描。在最后一个时间点后，测量了离体组织分布以证实体内 PET 数据。在注射 Ac-NM600 后 4 和 24 小时，测定了小鼠的离体组织分布。PET/CT 图像显示肿瘤中摄取升高且持续的 La-NM600。低骨蓄积证实了缀合物的体内稳定性。离体生物分布研究验证了图像衍生的定量数据，并且 La-NM600 和 Ac-NM600 组织分布的比较表明这两种放射性示踪剂具有相似的生物分布。这些发现表明镧是一种合适的成像替代物，可用于研究 Ac 放射性治疗剂的体内生物分布。
