Neuroimaging techniques, including positron emission tomography (PET), are ideally suited for studies of addiction. These minimally invasive modalities yield information about acute and long-term drug-induced structural and functional changes in the brain over time. Changes can be observed in the brains of human and animal subjects during drug self-administration. Neuroimaging with PET allows precise quantification and visualization of the drug and its rates of movement in the body. In addition, imaging reveals recovery of function and reappearance of neuronal markers in abstinent drug users. Evidence that suggests that PET may have use in identifying individuals predisposed to become addicted is emerging. Finally, candidate pharmacotherapies for drug addiction can be critically evaluated. These unique assets clearly point to the use of these strategies for addiction studies.