Normandin Marc D, Zheng Ming-Qiang, Lin Kuo-Shyan, Mason N Scott, Lin Shu-Fei, Ropchan Jim, Labaree David, Henry Shannan, Williams Wendol A, Carson Richard E, Neumeister Alexander, Huang Yiyun
PET Center, Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA.
Molecular Oncology Department, BC Cancer Agency Research Centre, Vancouver, British Columbia, Canada.
J Cereb Blood Flow Metab. 2015 Aug;35(8):1313-22. doi: 10.1038/jcbfm.2015.46. Epub 2015 Apr 1.
The Radiotracer [(11)C]OMAR was developed for positron emission tomography (PET) imaging of cannabinoid type-1 receptors (CB1R). The objectives of the present study were to evaluate kinetic analysis methods, determine test-retest reliability, and assess gender differences in receptor availability. Dynamic PET data were acquired in 10 human subjects, and analyzed with one-tissue (1T) and two-tissue (2T) compartment models and by the Logan and multilinear analysis (MA1) methods to estimate regional volume of distribution (VT). The 2T model inclusive of a vascular component (2TV) and MA1 were the preferred techniques. Test-retest reliability of VT was good (mean absolute deviation ~9%; intraclass correlation coefficient ~0.7). Tracer parent fraction in plasma was lower in women (P<0.0001). Cerebral uptake normalized by body weight and injected dose was higher in men by 17% (P<0.0001), but VT was significantly greater in women by 23% (P<0.0001). These findings show that [(11)C]OMAR binding can be reliably quantified by the 2T model or MA1 method and demonstrate the utility of this tracer for in vivo imaging of CB1R. In addition, results from the present study indicate that gender difference in receptor binding should be taken into consideration when [(11)C]OMAR is used to quantify CB1R availability in neuropsychiatric disorders.
放射性示踪剂[(11)C]OMAR被开发用于大麻素1型受体（CB1R）的正电子发射断层扫描（PET）成像。本研究的目的是评估动力学分析方法，确定重测信度，并评估受体可用性的性别差异。对10名人类受试者进行了动态PET数据采集，并使用单组织（1T）和双组织（2T）房室模型以及Logan和多线性分析（MA1）方法进行分析，以估计区域分布体积（VT）。包含血管成分的2T模型（2TV）和MA1是首选技术。VT的重测信度良好（平均绝对偏差约为9%；组内相关系数约为0.7）。女性血浆中的示踪剂母体分数较低（P<0.0001）。按体重和注射剂量归一化的脑摄取量男性比女性高17%（P<0.0001），但VT女性比男性显著高23%（P<0.0001）。这些发现表明，[(11)C]OMAR结合可以通过2T模型或MA1方法可靠地定量，并证明了这种示踪剂在CB1R体内成像中的实用性。此外，本研究结果表明，当使用[(11)C]OMAR定量神经精神疾病中的CB1R可用性时，应考虑受体结合的性别差异。
