When Medicare Covers PET Scans and When It Doesn't

Medicare covers PET scans, but only for specific conditions and only when your doctor orders them the right way

Medicare Part B covers positron emission tomography (PET) scans for certain cancers, neurological conditions, and cardiac problems. The scan itself is covered at 80 percent of the approved amount after you meet your Part B deductible — you pay the remaining 20 percent. But Medicare will not pay if your doctor orders the scan for a condition not on the approved list, or if they do not follow the required documentation steps before the scan happens.

The conditions Medicare covers PET scans for have changed over time and vary by the type of scan. Oncology (cancer) PET scans are the most commonly covered. Dementia and Alzheimer's disease PET scans are covered under specific circumstances. Cardiac PET scans are covered for certain heart conditions. Your doctor needs to know which diagnosis code Medicare requires for your particular scan, because submitting the wrong code will result in a denial.

Key Takeaways

Medicare Part B covers PET scans for certain cancers, some neurological conditions, and specific cardiac problems, but not for screening or monitoring in most cases.
Your doctor must order the scan with the correct diagnosis code and follow Medicare's documentation requirements, or the claim will be denied.
You pay 20 percent of the approved amount after your Part B deductible; the actual out-of-pocket cost depends on whether your provider is in-network and accepts Medicare assignment.
If your scan is denied, you have the right to appeal, and your doctor can request a coverage information before the scan to confirm Medicare will pay.

What conditions may have access to for Medicare-covered PET scans

Medicare covers PET scans for initial diagnosis, staging, and restaging of certain cancers. These include lung cancer, lymphoma, melanoma, head and neck cancers, and colorectal cancer. The scan must be ordered to detect cancer or determine how far it has spread, not to monitor treatment response in most cases. Your doctor will know whether your specific cancer type and stage meet Medicare's requirements.

For neurological conditions, Medicare covers PET scans for dementia and Alzheimer's disease, but only when other tests have not given a clear diagnosis and the scan will change your treatment plan. A standard MRI or CT scan must be done first. The scan cannot be ordered just to confirm what is already known or to monitor decline over time.

Cardiac PET scans are covered for patients with known coronary artery disease when other tests have been inconclusive and the scan will determine whether you need a procedure like angioplasty or bypass surgery. Routine screening or follow-up scans are not covered.

How your doctor orders a PET scan so Medicare will pay

Your doctor must submit the scan order with the correct diagnosis code — the specific medical code that matches both your condition and the reason for the scan. Using the wrong code is the most common reason Medicare denies PET scan claims. Your doctor's office should know which codes Medicare accepts for your diagnosis; if they are unsure, they can contact Medicare directly or check the Local Coverage information (LCD) for your region.

Your doctor should also document in your medical record why the scan is medically necessary — what other tests were done, what the results showed, and how the PET scan will change your treatment. Medicare reviewers look for this documentation when they process the claim. If the documentation is weak, the claim may be denied even if your condition is on the covered list.

Some doctors request a coverage information from Medicare before ordering the scan. This is a formal question to Medicare asking whether they will pay for your specific scan. It takes about two weeks and removes the risk of ordering the scan and then finding out Medicare will not pay. You can ask your doctor to request one if you are concerned about cost.

What you will pay out of pocket

If Medicare covers your PET scan, you pay 20 percent of the approved amount after you have met your Part B deductible for the year. The approved amount is what Medicare decides the scan is worth, not what the imaging center actually charges. If the imaging center is in-network and accepts Medicare assignment, they agree to accept the approved amount as payment in full (except for your 20 percent share). If they do not accept assignment, you may owe the difference between the approved amount and their actual charge.

The actual dollar amount varies widely depending on your location and the imaging center. A PET scan typically costs between $3,000 and $7,000 before insurance, but Medicare's approved amount is usually lower. Your 20 percent share might be $400 to $800, depending on the approved amount in your area. Call the imaging center before your scan and ask what Medicare's approved amount is for your specific scan type, then calculate 20 percent of that number.

If you have a Medigap or Medicare Advantage plan, your out-of-pocket cost may be lower. Medigap plans often cover the 20 percent coinsurance. Medicare Advantage plans vary — some cover PET scans at a copay, others at coinsurance. Check your plan documents or call your plan to find out what you will owe.

What happens if Medicare denies your PET scan claim

If your claim is denied, you will receive a notice called an Explanation of Benefits (EOB) explaining why. The most common reasons are: the diagnosis code was wrong, the medical documentation did not support the scan as medically necessary, or the condition is not on Medicare's covered list. Read the denial notice carefully — it will tell you which reason applies to your claim.

You have the right to appeal a denial. The appeal process has multiple levels: you can ask for reconsideration, then request a hearing before an administrative law judge, then appeal to the Medicare Appeals Council. Most appeals are handled on paper — you submit a written request and supporting documents. Your doctor can help by writing a letter explaining why the scan was medically necessary. Many denials are overturned on appeal, especially if the medical documentation was incomplete the first time.

If you want to avoid the risk of denial altogether, ask your doctor to request a coverage information before the scan is ordered. This is not the same as an appeal — it is a question to Medicare asking in advance whether they will pay. If Medicare says no, you can decide whether to pay out of pocket or skip the scan. If Medicare says yes, you know the claim will be covered.

PET scans for screening and monitoring

Medicare does not cover PET scans for screening — that is, to look for cancer or disease in people with no symptoms or signs of illness. Even if you have a family history of cancer or dementia, a screening PET scan is not covered. This is true even if your doctor thinks it would be helpful.

Medicare also does not cover PET scans ordered only to monitor how well treatment is working or to watch for recurrence after treatment is finished. The scan must be ordered to make a diagnosis or decide on a treatment plan. If your doctor wants to order a PET scan for monitoring purposes, you will likely owe the full cost out of pocket.

Frequently Asked Questions

Can I get a PET scan if I have Medicare Advantage instead of Original Medicare?

Yes, but the coverage rules are the same — your plan must cover the scan for your specific condition. Medicare Advantage plans must cover at least what Original Medicare covers, but they can have different copays, coinsurance, or prior authorization requirements. Call your plan before scheduling the scan to confirm it is covered and find out what you will owe.

Do I need prior authorization from Medicare before my PET scan?

Original Medicare does not require prior authorization for PET scans, but some imaging centers request it anyway to confirm coverage before the scan. Medicare Advantage plans often do require prior authorization. Ask your doctor's office whether they will handle this step — if not, contact your insurance plan directly.

What if my doctor says the PET scan is medically necessary but Medicare's rules say it is not covered?

You can pay for the scan out of pocket, or you can ask your doctor to request a coverage information from Medicare. A coverage information is a formal review that sometimes results in coverage for scans that would normally be denied. If Medicare still says no, you can appeal, though appeals for off-label uses are less likely to succeed.

Will Medicare pay for a PET scan if I already had a CT scan or MRI?

Yes, if the earlier scan did not give a clear answer. For neurological conditions, Medicare actually requires that you have had an MRI or CT first. For cancer, a PET scan is often ordered after other imaging to get more information. The key is that your doctor must document why the PET scan is necessary in addition to the other tests.

How long does it take Medicare to decide whether to pay for my PET scan?

If your doctor submits the claim after the scan, Medicare usually processes it within two to four weeks. If you request a coverage information before the scan, it takes about two weeks. If your claim is denied and you appeal, reconsideration takes about two months, and a hearing before an administrative law judge can take six months or longer.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.