Imaging of the striatal dopamine system continues to dominate studies using positron emission tomography (PET) in substance use disorders (SUD). A key reason for this is the stability of the findings: most studies imaging the dopamine D2 family of receptors (D2R) and stimulant-induced dopamine release show blunting of striatal dopamine transmission in subjects with addiction. This phenotype is seen across SUDs, including cocaine, nicotine, alcohol, opiate, and methamphetamine. Reduced binding at the D2R persists independently of many clinical factors, and this effect is maintained following days to months of abstinence.