FIGURE 1. Summed images (from 7 to 60 min) for 1 subject for ¹¹C-L-deprenyl (H) (top row) and ¹¹C-L-deprenyl-D2 (D) (bottom row). Planes from left to right show heart and lungs (planes 4 and 1); liver, stomach, and spleen (planes 17 and 14); and kidneys (planes 24 and 21). Note reduced accumulation of ¹¹C with ¹¹C-L-deprenyl-D2. Rainbow color scale is used.