[18F]NIDF PET Imaging in Tau-related Diseases

Inclusion Criteria: 1. Between 18 and 90 years old; 2. No gender limitation; 3. Clinical diagnositic rerults supported the diagnosis of neurodegeneration, and there was no evidence of other neurological diseases; 4. Healthy participants or patients with probable Alzheimer's disease or with dementia due to other causes; 5. Informed consent signed in person by the subject or his legal guardian or caregiver. Exclusion Criteria: 1. Has allergy to \[18F\]NIDF or any of its excipients; 2. Incapable of providing written informed consent or lacking a legally authorized representative (LAR) to provide informed consent ; 3. Unwilling or unable to undergo PET scans tracer injections; 4. Any condition that, in the Investigator's opinion, could increase the risk to the participant, limit the participant's ability to tolerate the research procedures, or interfere with the collection/analysis of the data (e.g., renal or liver failure, advanced cancer); 5. Received an experimental drug or device within 1 month (whose efficacy or safety is unclear); 6. Have other serious neurological disorders, or gastrointestinal, cardiovascular, liver, kidney, blood system, tumor, endocrine, respiratory, immune deficiency, and other serious diseases; 7. Women who are currently pregnant or breastfeeding.