amyloid and tau PET imaging in dementia

Key points

Amyloid and tau PET scans are advanced tools that can show Alzheimer's-related proteins in the living brain, but they are not needed for everyone.
A positive amyloid scan does not automatically mean dementia; it must be interpreted along with symptoms and other tests.
These scans are most useful when the diagnosis is unclear or when considering new anti-amyloid treatments for early-stage Alzheimer's.
Insurance coverage varies; always check with the provider before scheduling.
The scan results can guide care planning, but they do not predict how fast the disease will progress.
Always discuss the risks, benefits, and alternatives with the doctor before proceeding.

General caregiving information, not medical advice. Check medications and major care changes with your clinician.

Ask the doctor: 'What specific information will this PET scan give us that we don't already know?' and 'How will it change the treatment or care plan?'
Verify whether your loved one's insurance covers amyloid or tau PET scans; call the insurer or ask the doctor's office before scheduling.
Prepare your loved one: explain they will get a tracer injection, wait 30–60 minutes, then lie still for 20–30 minutes. Bring a comfort item (e.g., blanket or music player with headphones).
Ask how results will be shared and request a written report for future reference and for other specialists.
If the scan is positive for amyloid, ask whether your loved one might be eligible for clinical trials or anti-amyloid drugs (e.g., lecanemab, donanemab), which are only for early-stage Alzheimer's.
Use results to guide planning: if Alzheimer's, address memory care, safety, and legal/financial decisions; if another dementia type, adjust support accordingly.

Do not assume a positive amyloid scan means your loved one has Alzheimer's dementia; many older adults have plaques without symptoms.
Do not push for a scan if the doctor says it is unnecessary; it may cause stress or cost without adding value.
Do not ignore the possibility of mixed dementia; a PET scan only shows amyloid and tau, not other proteins like alpha-synuclein or TDP-43.
Do not expect the scan to give a timeline or predict progression rates.
Do not skip discussing risks and benefits; PET radiation is low but still present.

Pre-Scan Question Checklist
Print or write down: 'Why is this scan recommended?', 'What will we learn?', 'How will it change treatment?', 'What are the risks?', 'What is the cost and insurance coverage?', 'How long will it take and how do we prepare?'
Scan Day Comfort Kit
Pack: favorite blanket or shawl, noise-canceling headphones/earplugs, calming music/audiobook, water bottle (if allowed), small snack for after scan, list of current medications and allergies.
Follow-Up Appointment Planner
Schedule follow-up to discuss results. Before appointment, write down: new symptoms or changes, questions about results, next steps to discuss (medications, trials, support services).
Clinical Trial Search Guide
If scan is positive for amyloid, search for eligible trials at ClinicalTrials.gov or sign up for the Alzheimer's Association's TrialMatch service. Bring trial details to the doctor to discuss eligibility.

Ask the doctor: 'Is my loved one a candidate for an amyloid or tau PET scan? What are the specific reasons for or against it?'

Ask: 'If the scan is positive, what are the next steps? Are there any new treatments or clinical trials available?'

Ask: 'What are the risks of the scan, including radiation exposure, and how do they compare to the benefits of a clearer diagnosis?'

Ask: 'If the scan is negative, what other conditions could be causing the symptoms? What other tests might be needed?'

Ask: 'How will the scan results affect my loved one's eligibility for long-term care insurance, disability benefits, or clinical trials?'