Department of Bioengineering, School of Engineering, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan.
Department of Diagnostic Radiology and Nuclear Medicine, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama 350-8550, Japan; Isotope Science Center, University of Tokyo, Bunkyo, Tokyo 113-0032, Japan.
Nucl Med Biol. 2022 Jul-Aug;110-111:1-9. doi: 10.1016/j.nucmedbio.2022.03.002. Epub 2022 Mar 17.
Production of Mo/Tc using an electron linear accelerator (linac) and activated carbon (AC)-based Tc generator (linac-AC) is an alternative approach to the conventional fission production of Mo/Tc. As a preliminary investigation of the clinical applicability of a linac-AC-derived Tc radiopharmaceutical, the biodistribution of linac-AC-derived [Tc]sodium pertechnetate ([Tc]NaTcO) was measured and compared against fission-derived [Tc]NaTcO at one time point.
Mo was produced by irradiating nonenriched MoO targets with bremsstrahlung photons generated from 55.5-MeV linac electron beams. Tc was then separated and purified from the Mo using an AC-based Tc generator. Subsequently, biodistribution of the linac-AC-derived [Tc]NaTcO in healthy female Slc:ICR mice (n = 6) was measured by dissection and compared with that of fission-derived [Tc]NaTcO (n = 4) at 30 min after injection.
The two types of [Tc]NaTcO exhibited similar biodistribution in all the organs and tissues examined: the uptakes of [Tc]NaTcO prepared from the linac-AC method and those prepared from the fission method were 138.9 ± 69.9%ID/g and 160.6 ± 49.2%ID/g in the thyroids, respectively, 33.4 ± 5.5%ID/g and 29.4 ± 9.1%ID/g in the salivary glands, respectively, and less than 10%ID/g in blood and all the other organs. No adverse effects were observed in the mice administered with either [Tc]NaTcO.
The clinical applicability of linac-AC-derived [Tc]NaTcO was suggested by its similar biodistribution with fission-derived [Tc]NaTcO at one time point. Further biodistribution studies at multiple time points are encouraged to demonstrate the bioequivalence between linac-AC- and fission-derived [Tc]NaTcO.
使用电子直线加速器（linac）和基于活性炭（AC）的 Tc 发生器（linac-AC）生产 Mo/Tc 是传统 Mo/Tc 裂变生产的替代方法。作为对 linac-AC 衍生 Tc 放射性药物临床应用的初步研究，在一个时间点测量了 linac-AC 衍生的 [Tc]高锝酸钠 ([Tc]NaTcO) 的生物分布，并与裂变衍生的 [Tc]NaTcO 进行了比较。
用 55.5-MeV linac 电子束产生的韧致辐射光子照射非浓缩 MoO 靶，产生 Mo。然后，使用基于 AC 的 Tc 发生器从 Mo 中分离和纯化 Tc。随后，通过解剖测量健康雌性 Slc:ICR 小鼠（n = 6）中 linac-AC 衍生的 [Tc]NaTcO 的生物分布，并与注射后 30 分钟时裂变衍生的 [Tc]NaTcO（n = 4）进行比较。
两种类型的 [Tc]NaTcO 在所有检查的器官和组织中表现出相似的生物分布：用 linac-AC 方法制备的 [Tc]NaTcO 和用裂变方法制备的 [Tc]NaTcO 的摄取率分别为甲状腺中的 138.9 ± 69.9%ID/g 和 160.6 ± 49.2%ID/g，唾液腺中的 33.4 ± 5.5%ID/g 和 29.4 ± 9.1%ID/g，血液和所有其他器官中的摄取量均小于 10%ID/g。给予两种 [Tc]NaTcO 的小鼠均未观察到不良反应。
在一个时间点，linac-AC 衍生的 [Tc]NaTcO 与裂变衍生的 [Tc]NaTcO 具有相似的生物分布，表明其临床应用具有可行性。鼓励进行多个时间点的进一步生物分布研究，以证明 linac-AC 和裂变衍生的 [Tc]NaTcO 之间的生物等效性。
