Purpose To investigate the value of 11C-CFT PET/CT dopamine transporter (DAT) imaging in differential diagnosis of multiple system atrophy (MSA) and Parkinson's disease (PD).Materials and Methods The 11C-CFT PET/CT images of clinically confirmed MSA patients (21 cases),PD patients (24 cases) and healthy adults (10 cases as normal control) were analyzed retrospectively.The volume of interest (VOI) were drawn manually,and the DAT binding indexes and asymmetry indexes of different regions of striatum,including caudate and putamen,were calculated.The differences of DAT binding indexes and asymmetry indexes among the above three groups were analyzed.Results Compared with the normal control group,the striatal DAT binding indexes of MSA group or PD group were significantly reduced (P＜0.05).There were no significant differences in DAT binding indexes between the MSA group and the PD group (P＞0.05).Compared with the normal control group,the DAT binding asymmetry indexes were significantly increased in the PD group (P＜0.05),but the indexes showed no significant differences in MSA group (P＞0.05).The DAT asymmetry indexes of caudate and putamen in the PD group were higher than those in the MSA group (P＜0.05).Conclusion 11C-CFT PET/CT imaging can detect the degeneration of dopaminergic neurons in striatum.The number of striatal dopamine transporters declines in both MSA and PD patients,but the asymmetry of striatal dapamine transporter in PD patients is higher than that in MSA patients.11C-CFT PET/CT can differentiate MSA and PD.