Imaging transporters for dopamine and other neurotransmitters in brain
There has been substantial progress in the imaging of dopamine transporters. The earliest positron emission tomography (PET) experiments used carbon-11 labeled nominfensine, whereas recent investigations by both PET and single photon emission computed tomography (SPECT) utilize a variety of ligands with a variety of properties and address many biological questions. The earliest ligands utilized, [11C]nomifensine and [11C]cocaine, were somewhat limited because of low signal-to-noise ratios Nevertheless, [11C]cocaine as a ligand continues to be popular, because it is the same authentic substance that is abused around the world. The best, current 3-substituted phenyltropane ligands, such as RTI-55, have vastly improved signal-to-noise ratios.