Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
J Nucl Med. 2013 Jun;54(6):969-76. doi: 10.2967/jnumed.112.109090. Epub 2013 Mar 27.
We have developed a SPECT imaging system, AwakeSPECT, to enable molecular brain imaging of untrained mice that are conscious, unanesthetized, and unrestrained. We accomplished this with head tracking and motion correction techniques.
The capability of the system for motion-corrected imaging was demonstrated with a (99m)Tc-pertechnetate phantom, (99m)Tc-methylene diphosphonate bone imaging, and measurement of the binding potential of the dopamine transporter radioligand (123)I-ioflupane in mouse brain in the awake and anesthetized (isoflurane) states. Stress induced by imaging in the awake state was assessed through measurement of plasma corticosterone levels.
AwakeSPECT provided high-resolution bone images reminiscent of those obtained from CT. The binding potential of (123)I-ioflupane in the awake state was on the order of 50% of that obtained with the animal under anesthesia, consistent with previous studies in nonhuman primates. Levels of stress induced were on the order of those seen in other behavioral tasks and imaging studies of awake animals.
These results demonstrate the feasibility of SPECT molecular brain imaging of mice in the conscious, unrestrained state and demonstrate the effects of isoflurane anesthesia on radiotracer uptake.
我们开发了一种 SPECT 成像系统，AwakeSPECT，以使未经过训练的清醒、未麻醉和未束缚的小鼠能够进行分子脑成像。我们通过头部跟踪和运动校正技术实现了这一目标。
使用 (99m)Tc-高锝酸盐体模、(99m)Tc-亚甲基二膦酸盐骨成像以及测量在清醒和麻醉（异氟烷）状态下小鼠脑内多巴胺转运体放射性配体 (123)I-碘托烷的结合势，证明了该系统进行运动校正成像的能力。通过测量血浆皮质酮水平来评估在清醒状态下成像引起的应激。
AwakeSPECT 提供了类似于 CT 获得的高分辨率骨图像。在清醒状态下，(123)I-碘托烷的结合势约为麻醉动物获得的结合势的 50%，与非人类灵长类动物的先前研究一致。诱导的应激水平与其他行为任务和清醒动物的成像研究中观察到的水平相当。
这些结果表明，在清醒、不受约束的状态下对小鼠进行 SPECT 分子脑成像具有可行性，并证明了异氟烷麻醉对放射性示踪剂摄取的影响。
