The short answer
A PSMA PET scan is an imaging test used to help find prostate cancer cells in the body. A radioactive molecule attaches to a protein called PSMA on prostate cancer cells, and a PET scanner shows where it collects. NCI says it may be used when prostate cancer may have come back or spread, and to help plan treatment.
A PSMA PET scan helps find prostate cancer cells in the body.
It uses a radioactive molecule that attaches to a protein called PSMA on the surface of prostate cancer cells.
NCI says it may be used to help diagnose prostate cancer that may have come back or spread, and to help plan treatment.
A regular PET scan uses radioactive sugar. A PSMA PET scan uses a different molecule that targets PSMA.
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This page is for people who have been told to expect a PSMA PET scan, or who see the term on a report. It explains what the scan is and what NCI says it is used for.
What the scan does
NCI describes a PSMA PET scan as an imaging procedure used to help find prostate cancer cells in the body.
For the scan, a cell-targeting molecule linked to a radioactive substance is injected into the body. It travels through the blood. It attaches to a protein called prostate-specific membrane antigen, or PSMA, that is found on the surface of prostate cancer cells. A PET scanner then detects where the radioactive molecule has collected in high amounts. That shows where prostate cancer cells are in the body.
What PSMA is
NCI says PSMA is a protein that is usually found on the surface of normal prostate cells. It is found in higher amounts on prostate cancer cells. That difference is why PSMA can be used as a target in imaging.
What the scan is used for
NCI says a PSMA PET scan may be used to help diagnose prostate cancer that may have come back or spread to other parts of the body. NCI's prostate cancer summary lists bone, lymph nodes and other organs as places it may help find cancer that has spread outside the prostate. NCI says it may also be used to help plan treatment.
If your PSA blood level has been rising after treatment, you may hear the term biochemical recurrence. NCI uses it for a rise in PSA after surgery or radiation, and says it may mean the cancer has come back. Our page on biochemical recurrence covers it, and what a rising PSA means explains the blood test.
How it differs from a regular PET scan
NCI says a regular PET scan uses a small amount of radioactive glucose, which is a sugar, injected into a vein. Cancer cells often take up more glucose than normal cells do, so the pictures can be used to find cancer in the body.
A PSMA PET scan uses a different molecule, one that attaches to PSMA. If you have read about a regular PET scan, see what hypermetabolic means and the PET scan page.
Reading the result
Your report will describe where the radioactive molecule collected. A description of a spot is not a diagnosis by itself. Your care team will read it together with your PSA results, your earlier scans and your history. Ask what each finding means for you and whether anything needs a biopsy or another test.
Is this urgent?
Ask your care team when the result will be ready and who will go over it with you. If you have new or worsening symptoms while you wait, call your care team right away. If you think you are having an emergency, call 911.
What to ask your team
- Why did you choose a PSMA PET scan for me?
- What question should the scan answer?
- How do I prepare, and how long will it take?
- If it shows spots, what happens next?
- If it shows nothing, does that change the plan?
Sources
Common questions
What is a PSMA PET scan?
NCI defines it as an imaging procedure used to help find prostate cancer cells in the body. A cell-targeting molecule linked to a radioactive substance is injected into the body. It attaches to a protein called PSMA on prostate cancer cells. A PET scanner detects high concentrations of the radioactive molecule and shows where the prostate cancer cells are.
What is PSMA?
PSMA stands for prostate-specific membrane antigen. NCI says it is a protein that is usually found on the surface of normal prostate cells but is found in higher amounts on prostate cancer cells.
Why would I have a PSMA PET scan?
NCI says it may be used to help diagnose prostate cancer that may have come back or spread to other parts of the body, such as bone or lymph nodes. It may also be used to help plan treatment. Ask your care team why it was ordered for you.
How is it different from a regular PET scan?
NCI says a regular PET scan uses a small amount of radioactive glucose (sugar) and shows areas where the glucose is taken up. A PSMA PET scan uses a molecule that attaches to PSMA instead.
Is a PSMA PET scan the same as a PSA test?
No. A PSA test is a blood test. A PSMA PET scan is an imaging scan.
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Written by: Cancer ExplainedSources last checked: 2026-10-19 what this meansLast updated: 2026-10-19Next planned review: 2027-10-19
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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