Analysis of 18F-XTR006 PET Imaging in Cognitively Normal Subjects, and Patients With MCI and AD

Inclusion Criteria: Inclusion Criteria for All Subjects: 1. Male or female subjects aged ≥50 years. 2. Able to tolerate both PET and MRI examinations. 3. Must use contraceptive measures during the study period and for 6 months after study completion. 4. Written informed consent must be obtained before any assessment is performed. Inclusion Criteria for Cognitively Normal Subjects: 1)CDR (Clinical Dementia Rating) score of 0. 2）MMSE (Mini-Mental State Examination) score ≥28. 3）Negative visual reading result on brain Aβ-PET imaging. Inclusion Criteria for Subjects with MCI: 1. Meet the core clinical criteria for MCI due to AD according to 2011 NIA-AA (National Institute on Aging-Alzheimer's Association) standards 2. Positive visual reading result on brain Aβ-PET imaging Inclusion Criteria for Subjects with AD: 1. Meet the specific clinical phenotype criteria for typical AD according to 2014 International Working Group (IWG)-2 standards: 2. Positive visual reading result on brain Aβ-PET imaging. Exclusion Criteria: 1. Diagnosis of atypical AD, frontotemporal lobar degeneration (FTLD), Lewy body dementia, or other types of dementia. 2. Current significant psychiatric illness with symptoms that prevent completion of imaging procedures. 3. MRI-confirmed structural brain abnormalities, such as large stroke or intracranial mass lesions. 4. Claustrophobia. 5. History of alcohol abuse or drug abuse/dependence. 6. Allergy to the study drug or any of its components. 7. Women who are currently breastfeeding.