Quantification of the neurokinin 1 receptor ligand [C-11]R116301

: Wolfensberger SP, Maruyama K, van Berckel BN, Lubberink M, Airaksinen AJ, Boellaard R, Luurtsema G, Reddingius W, Janssens FE, Veltman DJ, Windhorst AD, Leysen JE, Lammertsma AA

Publisher: LIPPINCOTT WILLIAMS & WILKINS

: 2011

: Nuclear Medicine Communications

: NUCLEAR MEDICINE COMMUNICATIONS

: NUCL MED COMMUN

: 32

: 10

: 896

: 902

: 7

: 0143-3636

DOI: https://doi.org/10.1097/MNM.0b013e328347e96f

Purpose Neurokinin 1 (NK1) receptors have been implicated in depression, anxiety, and pain perception. Recently, it was shown that, in the human brain, a specific NK1 receptor-related signal was obtained with the novel radioligand, [C-11]R116301, using positron emission tomography. The purpose of this study was to evaluate various methods for quantifying specific [C-11]R116301 binding.Methods Two dynamic 90-min [C-11]R116301 scans, separated by 5 h, were performed in 11 healthy volunteers. In three patients, the second scan was performed after an oral blocking dose of 125 mg of aprepitant, whereas in the other eight, no intervention was performed (test-retest). Whole striatum was used as the tissue of interest, as it has the highest density of NK1 receptors. Cerebellum was used as the reference tissue.Results Reference tissue models were stable with the simplified reference tissue model (SRTM) performing best. Average (+/- standard deviation) SRTM-derived mean nondisplaceable binding potential (BPND) of all (first) baseline scans was 0.64 +/- 0.31 (n=11), which reduced to -0.01 +/- 0.03 (n=3) after aprepitant administration. Test-retest results showed low variability (14.0 +/- 10.7%) and excellent reliability, as indicated by the intraclass correlation coefficient (0.93). The ratio of standardized uptake values of striatum and cerebellum minus 1, an approximation of BPND, showed very low variability (6.2 +/- 3.1%) with excellent reliability (intraclass correlation coefficient=0.98), and correlated well with SRTM-derived BPND (R-2 = 0.96).Conclusion SRTM is the model of choice for quantifying [C-11]R116301 binding. Semiquantitative tissue ratios hold promise for routine clinical applications. Nucl Med Commun 32:896-902 (C) 2011 Wolters Kluwer Health vertical bar I Lippincott Williams & Wilkins. Nuclear Medicine Communications 2011, 32:896-902