BACKGROUND Positron emission tomography (PET) is increasingly being used as an imaging modality for clinical and research applications in veterinary medicine. Amyloid PET has become a useful tool for diagnosing Alzheimer's disease (AD) in humans, by accurately identifying amyloid-beta (Aβ) plaques. Cognitive dysfunction syndrome in dogs shows cognitive and pathophysiologic characteristics similar to AD. Therefore, we assessed the physiologic characteristics of uptake of 18F-flutemetamol, an Aβ protein-binding PET tracer in clinical development, in normal dog brains, for distinguishing an abnormal state. Static and dynamic PET images of six adult healthy dogs were acquired after 18F-flutemetamol was administered intravenously at approximately 3.083 MBq/kg. For static images, PET data were acquired at 30, 60, and 90 min after injection. One week later, dynamic images were acquired for 120 min, from the time of tracer injection. PET data were reconstructed using an iterative technique, and corrections for attenuation and scatter were applied. Regions of interest were manually drawn over the frontal, parietal, temporal, occipital, anterior cingulate, posterior cingulate, and cerebellar cortices, cerebral white matter, midbrain, pons, and medulla oblongata. After calculating standardized uptake values with an established formula, standardized uptake value ratios (SUVRs) were obtained, using the cerebellar cortex as a reference region. RESULTS Among the six cerebral cortical regions, the cingulate cortices and frontal lobe showed the highest SUVRs. The lowest SUVR was observed in the occipital lobe. The average values of the cortical SUVRs were 1.25, 1.26, and 1.27 at 30, 60, and 90 min post-injection, respectively. Tracer uptake on dynamic scans was rapid, peaking within 4 min post-injection. After reaching this early maximum, cerebral cortical regions showed a curve with a steep descent, whereas cerebral white matter demonstrated a curve with a slow decline, resulting in a large gap between cerebral cortical regions and white matter. CONCLUSION This study provides normal baseline data of 18F-flutemetamol PET that can facilitate an objective diagnosis of cognitive dysfunction syndrome in dogs in future.

中文翻译：

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使用正电子发射断层扫描观察犬脑中 18F-氟替他莫摄取的时间和解剖分布。


背景技术正电子发射断层扫描（PET）越来越多地被用作兽医学临床和研究应用的成像方式。通过准确识别淀粉样蛋白 β (Aβ) 斑块，淀粉样蛋白 PET 已成为诊断人类阿尔茨海默病 (AD) 的有用工具。狗的认知功能障碍综合征表现出与AD相似的认知和病理生理特征。因此，我们评估了正常狗大脑中 18F-氟替他莫（一种临床开发中的 Aβ 蛋白结合 PET 示踪剂）摄取的生理特征，以区分异常状态。以大约 3.083 MBq/kg 静脉注射 18F-氟替他莫后，获得了六只成年健康狗的静态和动态 PET 图像。对于静态图像，在注射后 30、60 和 90 分钟采集 PET 数据。一周后，采集自示踪剂注射时起 120 分钟的动态图像。使用迭代技术重建 PET 数据，并应用衰减和散射校正。手动在额叶、顶叶、颞叶、枕叶、前扣带皮层、后扣带皮层和小脑皮质、大脑白质、中脑、脑桥和延髓上绘制感兴趣区域。使用既定公式计算标准化摄取值后，使用小脑皮层作为参考区域获得标准化摄取值比率（SUVR）。结果 在六个大脑皮层区域中，扣带皮层和额叶的 SUVR 最高。枕叶的 SUVR 最低。注射后 30 分钟、60 分钟和 90 分钟时皮质 SUVR 的平均值分别为 1.25、1.26 和 1.27。 动态扫描中示踪剂的吸收很快，在注射后 4 分钟内达到峰值。在达到这个早期最大值后，大脑皮质区域呈现出陡峭下降的曲线，而大脑白质呈现出缓慢下降的曲线，导致大脑皮质区域和白质之间存在较大差距。结论 本研究提供了 18F-氟替他莫 PET 的正常基线数据，有助于将来对犬认知功能障碍综合征进行客观诊断。