Alzheimer's disease (AD) has become the fourth leading cause of death among people aged 65 and above in China. PET/CT plays a significant role in the clinical diagnosis and research on the pathogenesis of AD. The combined use of PET/CT and digital technology within the Alzheimer's Disease Neuroimaging Initiative (ADNI) provides important scientific support for tracking the trajectory of cognitive changes in patients and improving the accuracy of clinical diagnosis. This article focuses on reviewing the research progress in exploring the pathological progression patterns and early diagnosis of AD using PET/CT within ADNI over the past three years.