To investigate the primary brain regions of precursors of Alzheimer's disease and Alzheimer's disease by novel molecular probe \[18F\]AV45(Aβ) and \[18F\]AV1451(Tau)PET/CT imaging. And the distribution of positive lesions in the brain area affecting the simple mental state examination and the Montreal Cognitive Assessment Scale in AD patients; It is expected to provide molecular imaging information for further study of the pathogenesis of AD. After clinical transformation, objective and quantitative positive diagnostic criteria for \[18F\]AV45 and \[18F\]AV1451PET/CT in the diagnosis of early Alzheimer's disease were established to avoid the defects of relying on the subjective experience of doctors and time-consuming diagnosis.