TY - JOUR T1 - Parametric Imaging and Test–Retest Variability of <sup>11</sup>C-(+)-PHNO Binding to D<sub>2</sub>/D<sub>3</sub> Dopamine Receptors in Humans on the High-Resolution Research Tomograph PET Scanner JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 960 LP - 966 DO - 10.2967/jnumed.113.132928 VL - 55 IS - 6 AU - Jean-Dominique Gallezot AU - Ming-Qiang Zheng AU - Keunpoong Lim AU - Shu-fei Lin AU - David Labaree AU - David Matuskey AU - Yiyun Huang AU - Yu-Shin Ding AU - Richard E. Carson AU - Robert T. Malison Y1 - 2014/06/01 UR - http://jnm.snmjournals.org/content/55/6/960.abstract N2 - 11C-(+)-4-propyl-9-hydroxynaphthoxazine (11C-(+)-PHNO) is an agonist radioligand for imaging dopamine D2 and D3 receptors in the human brain with PET. In this study we evaluated the reproducibility of 11C-(+)-PHNO binding parameters using a within-day design and assessed parametric imaging methods. Methods: Repeated studies were performed in 8 subjects, with simultaneous measurement of the arterial input function and plasma free fraction. Two 11C-(+)-PHNO scans for the same subject were separated by 5.4 ± 0.7 h. After compartment models were evaluated, 11C-(+)-PHNO volumes of distribution (VT) and binding potentials relative to the concentration of tracer in plasma (BPP), nondisplaceable tracer in tissue (BPND), and free tracer in tissue (BPF) were quantified using the multilinear analysis MA1 method, with the cerebellum as the reference region. Parametric images of BPND were also computed using the simplified reference tissue model (SRTM) and SRTM2. Results: The test–retest variability of 11C-(+)-PHNO BPND was 9% in D2-rich regions (caudate and putamen). Among D3-rich regions, variability was low in the pallidum (6%) but higher in substantia nigra (19%), thalamus (14%), and hypothalamus (21%). No significant mass carry-over effect was observed in D3-rich regions, although a trend in BPND was present in the substantia nigra (−14% ± 15%). Because of the relatively fast kinetics, low-noise BPND parametric images were obtained with both SRTM and SRTM2 without spatial smoothing. Conclusion: 11C-(+)-PHNO can be used to compute low-noise parametric images in both D2- and D3-rich regions in humans. ER -