FIGURE 1.

Parent radioligand fraction, radioactivity concentrations (conc), and radiometabolite profile in plasma from 40-y-old healthy man injected with 755 MBq of ¹¹C-NOP-1A. (A) Fraction of unchanged parent radioligand ¹¹C-NOP-1A (○) in plasma fitted by Hill function. (B) Time course of parent ¹¹C-NOP-1A concentration (○) in arterial plasma fitted by multiplying triexponential-fitted total plasma radioactivity and Hill function–fitted plasma parent fraction. (C) Radiochromatogram illustrating plasma composition 40 min after injection of ¹¹C-NOP-1A. Radioactivity was measured in counts per second (cps). Peaks A to D and parent are labeled with increasing lipophilicity.