Dopamine transporter (DAT) imaging, such as positron emission tomography (PET) with [11C]2β-carbomethoxy-3β-(4-fluorophenyl) tropane ([11C]CFT) and single photon emission computed tomography (SPECT) with [123I]2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane ([123I]FP-CIT; DaTscanTM, GE Healthcare), is a powerful tool in the differential diagnosis of idiopathic Parkinson’s disease (PD) from essential tremor or other secondary parkinsonism without nigrostriatal degeneration. This evidence concerns the gene SLC6A3 and secondary Parkinson disease.