Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada.
Med Phys. 2013 Apr;40(4):042502. doi: 10.1118/1.4793756.
Manganese(II) is employed as a contrast agent with magnetic resonance imaging (MRI) for study of neuronal activation in rats and mice. However, at the concentrations required for MRI, Mn may induce pharmacological or toxic effects. Positron emission tomography (PET) imaging of (52)MnCl2 at tracer doses has the potential to allow similar Mn studies as manganese-enhanced MRI while providing quantitative results and avoiding toxic effects. In this work, (52)MnCl2 is produced and characterized as a PET tracer in phantoms and in rats.
(52)MnCl2 was produced by proton irradiation of natural Cr foil and separated by column chromatography. Images were acquired on a Siemens Focus 120 small animal PET scanner. Phantom images were acquired to assess uniformity, resolution, cascade background correction, and count rate linearity. Images of rats were also acquired after systemic and intracerebroventricular (ICV) administration of (52)MnCl2 to investigate Mn(II) distribution in vivo.
Irradiation yield was 74.6 ± 8.5 kBq/μA min (52)Mn at end of bombardment with initial specific activity of at least 3.5 MBq/nmol. (52)Mn PET images show similar uniformity and resolution to (18)F. (18)F based detector efficiency normalization is adequate for (52)Mn imaging. Subtraction of a rescaled random events distribution from sinogram data is effective for cascade correction of (52)Mn PET data. After systemic injection, (52)Mn appears in structures throughout the body of rats, including bones, liver, intestines, and the pituitary gland, but does not appear detectably throughout the brain. After ICV injection, (52)Mn remains in the brain and spinal cord.
(52)Mn is a promising tracer for small animal PET imaging, yielding image quality comparable to (18)F. Potential applications include studies similar to Mn-enhanced neuronal MRI, and in other organ systems including bones, spinal cord, and the digestive tract.
锰（II）被用作磁共振成像（MRI）的对比剂，用于研究大鼠和小鼠的神经元激活。然而，在 MRI 所需的浓度下，Mn 可能会引起药理或毒性作用。放射性核素（52）MnCl2 的正电子发射断层扫描（PET）成像具有允许类似 Mn 增强 MRI 研究的潜力，同时提供定量结果并避免毒性作用。在这项工作中，（52）MnCl2 作为 PET 示踪剂在体模和大鼠中进行了生产和表征。
通过质子辐照天然 Cr 箔生产（52）MnCl2，并通过柱色谱法进行分离。使用 Siemens Focus 120 小动物 PET 扫描仪采集图像。采集图像以评估均匀性、分辨率、级联背景校正和计数率线性。还在系统和脑室内（ICV）给予（52）MnCl2 后采集大鼠图像，以研究 Mn（II）在体内的分布。
辐照产额为 74.6 ± 8.5 kBq/μA min（52）Mn，在末束时的初始比活度至少为 3.5 MBq/nmol。（52）Mn PET 图像显示出与（18）F 相似的均匀性和分辨率。（18）F 基于探测器效率归一化足以用于（52）Mn 成像。从能谱数据中减去重新缩放的随机事件分布对于级联校正（52）Mn PET 数据是有效的。在系统注射后，（52）Mn 出现在大鼠体内的结构中，包括骨骼、肝脏、肠道和垂体，但在大脑中未检测到。在 ICV 注射后，（52）Mn 留在大脑和脊髓中。
（52）Mn 是一种很有前途的小动物 PET 成像示踪剂，其图像质量可与（18）F 相媲美。潜在的应用包括类似 Mn 增强神经元 MRI 的研究，以及骨骼、脊髓和消化道等其他器官系统的研究。
