 Experimental Design and Method: After being medically cleared and giving informed consent, each participant will undergo up to three PET studies. In each study, the participant will receive a 5 mCi70 kg dose of the radioligand, 218FFA-85380-Injection. For one of the studies, the participants who smoke will receive nicotine by a nicotine patch Nicoderm, applied approximately 4 h before the scan. The patch will be removed 12 h after it is applied. For two studies one without and one with nicotine, participants who smoke will receive the radioligand as a bolus injection. Six of the participants who do not currently smoke control group will receive the radioligand as a bolus injection twice without nicotine either time. For the third study, all participants will receive the radioligand as a bolus injection followed by a continuous infusion bolus injectioninfusion combination. Six of the participants who do not currently smoke control group will receive the radioligand as a bolus plus infusion injection twice. For each study, a series of brain PET scans will be acquired for 8 h beginning at the time of the injection. The data from the PET scans without and with nicotine patch smokers only will be used to determine the total and non-specific accumulation of radioactivity in the brain. The data from the equivalent two PET scans for the controls will be used to determine the test-retest reliability of the measure. The data from the PET scans acquired from the bolusinfusion paradigm will be used to demonstrate the feasibility of a shorter scanning period for quantitation studies. It is anticipated that several of the participants will choose not to continue after the first scan. The study design accommodates this expectation. 