Dopamine (DA) and serotonin (5-HT) transporter availability in heroin users and healthy controls was measured using [I-123]beta-CIT and SPECT imaging. Heroin users had statistically similar striatal DA and brainstem and diencephalon 5-HT transporter availability compared with controls. No associations between transporter availability and heroin use characteristics were found. (C) 2010 Elsevier Ireland Ltd. All rights reserved.