MRI slice templates of rhesus monkey brain (top), corresponding PET slices acquired using ¹⁸F-nifrolidine (middle), and axial summed PET slices showing the distribution of ¹⁸F-nifrolidine (bottom). Nifrolidine is being evaluated as a PET agent for nicotine α4β2 receptor subtypes, which have been implicated in the study of Alzheimer's disease, schizophrenia, substance abuse, lung cancer, and other disorders.