Figure 6.

¹¹C-Carfentanil PET imaging of the brain following intranasal naloxone at 0-60 min or 300-600 min. (Adapted from Johansson et al., 2019). ROI-based binding potential was determined using PET imaging of ¹¹C-Carfentanil superimposed on a brain MRI template without naloxone administration (upper left image), at 0-60 min following 4 mg of naloxone (upper second image from left), at 0-60 min following 2 mg naloxone (upper third image from left), or at 300-360 min following 2 or 4 mg naloxone. The bottom row indicates percent occupancy of naloxone relative to placebo at the doses administered in the upper row. BP_ND is the binding potential of [¹¹C] carfentanil relative to the uptake of the tracer in the non-displaceable compartment.