Purpose To evaluate the combined brain imaging of 11C-CFT and 18F-FDG PET/CT in Parkinson's syndrome,and to test the clinical value of dual tracer combined imaging in differential diagnosis of Parkinson's syndrome.Materials and Methods A retrospective analysis was made on 73 patients with Parkinson's syndrome who underwent 11C-CFT and 18F-FDG PET/CT dual tracer combined brain imaging in the Affiliated Hospital of Guizhou Medical University from January 2016 to February 2021.The patients were divided into Parkinson's disease(PD)group(n=40),multiple system atrophy(MSA)group(n=20),and progressive supranuclear palsy(PSP)group(n=13).Ten normal controls recruited from September to October 2020 were selected as the normal control group.The images were analyzed and summarized,and the caudate nucleus index,putamen index as well as the radioactive uptake cluster values of the corresponding brain regions were compared.Results Compared with the normal control group,all three patient groups showed damage to the dopamine system.PD group showed significant asymmetry,MSA group had more uniform damage,and PSP group had the most severe damage to the dopamine system.In terms of glucose metabolism,the glucose metabolism in the cerebellar hemisphere of MSA group was significantly reduced compared with other groups(P<0.05).Compared with the normal control group,MSA group only had an increase in glucose metabolism in the diseased thalamus,and the difference was statistically significant(P<0.05).There was a statistically significant difference in midbrain glucose metabolism between PSP group and PD group compared with MSA group(P<0.05).In terms of frontal lobe and anterior cingulate cortex,there were significant differences in glucose metabolism between PSP group,normal control group,and PD group on one or both sides of the cerebral cortex(P<0.05).Conclusion Double tracer can make up for the deficiency of single tracer in differential diagnosis,so as to early make accurate diagnosis of Parkinson's syndrome.