The PSMA PET scan is an imaging test that can help doctors learn whether prostate cancer has spread outside your prostate gland.

Approximately 1 in 8 males will receive a diagnosis of prostate cancer in their lifetime, according to the American Cancer Society.

Early diagnosis and treatment may help reduce the cancer’s severity, progression, and risk of complications.

The PSMA PET scan is a type of positron emission tomography (PET) scan that uses a special dye with radioactive tracers that bind to prostate-specific membrane antigens (PSMA), a protein found in high levels on the surface of the prostate cancer cells.

This dye helps the cancer cells show up more clearly on scans.

The Food and Drug Administration (FDA) has approved the following PSMA-targeted tracers:

PSMA PET scans may be more accurate than conventional testing approaches for diagnosing metastatic prostate cancer.

Keep reading to learn more about the PSMA PET scan.

“Your doctor might order PSMA PET-CT at the time you are diagnosed with prostate cancer if you have any risk factors for metastatic disease,” said Dr. Michael Feuerstein, the Chief of Urology at New York Presbyterian-Westchester Hospital.

According to Feuerstein, doctors use the following measurements to assess the risk of metastatic prostate cancer:

  • Prostate-specific antigen (PSA): This is a protein made by the prostate that’s found in the semen and blood. It tends to be elevated in people with prostate cancer. A PSA blood test is one of the first tests doctors order to diagnose prostate cancer. You’re considered at risk of metastatic prostate cancer if you have a PSA blood level of 20 or higher.
  • Gleason grade: This system assigns a score to classify how many abnormal prostate cancer cells are found in a tissue biopsy. A Gleason grade of 7 (3+4) or higher puts you at higher risk of metastatic prostate cancer.

“Your doctor might also order the PSMA PET scan if you still have detectable prostate cancer after undergoing surgery to treat it,” said Feuerstein.

Additionally, they might order this test if you’ve been successfully treated for prostate cancer, but tests suggest the disease has come back. For example, blood tests that show rising PSA levels are a sign the cancer has returned.

In some cases, your doctor might order other tests for metastatic prostate cancer, such as CT, MRI, or bone scans.

“Your doctor might order conventional tests if the PSMA PET scan technology isn’t available in your region or your insurance plan doesn’t cover it,” said Feuerstein.

Research suggests the PSMA PET test is more accurate than conventional tests for diagnosing metastatic prostate cancer.

A 2020 study compared the PSMA PET scan with a conventional combination of CT and bone scans in high risk males who had recently received a diagnosis of prostate cancer.

Researchers found that the PSMA PET scan was 27% more accurate at detecting cancer in the pelvic lymph nodes or metastases outside the prostate than the conventional tests.

Another 2020 study evaluated males with prostate cancer who had received staging with a conventional combination of CT, MRI, and bone scans followed by PSMA PET scans. The PSMA PET scans increased the level of confidence in the staging results by 20%.

Both studies found that, in multiple cases, the PSMA PET scan results led to changes in people’s recommended treatment plans.

The PSMA PET procedure usually takes about 2 hours, although timing may vary.

To conduct a PSMA PET scan, a nurse or technician will inject a special dye with a radioactive tracer into one of your veins. They will ask you to wait approximately 30 to 60 minutes to allow the dye to travel throughout your body.

Next, you will be asked to lie down on a padded exam table. The table will then be slid through a PET-CT or PET-MRI scanner to create images of your body. This scan may take 30 minutes or longer to complete.

After the scan is finished, a specialist will review the images and report the results to your doctor. Your doctor will share the results with you.

The PSA test is different from the PSMA PET scan.

The PSA test is a blood test that measures the level of PSA in your blood. PSA is a protein produced by cells in your prostate gland. High levels of PSA are often a sign of prostate cancer.

The PSMA PET scan is used after PSA testing if your doctor isn’t sure if or where prostate cancer has spread. It can more accurately pinpoint where prostate cancer cells are located throughout the body.

Your doctor may order a PSA blood test to:

  • screen for prostate cancer if you don’t have symptoms of the disease
  • determine whether further tests are necessary to diagnose prostate cancer if you do have symptoms of the disease
  • check for signs that prostate cancer has come back if you’ve received successful treatment for the disease

PSA blood test results are not enough to diagnose prostate cancer or learn whether it has spread or returned. If you have high levels of PSA, your doctor will order other follow-up tests to develop an accurate diagnosis.

Your doctor will only order a PSMA PET scan if they think you may have prostate cancer that has spread beyond the prostate gland.

Is a PSMA PET scan a full-body scan?

Yes, PSMA PET scan is a full-body scan.

What percentage of prostate cancer is PSMA positive?

Research suggests that up 90% of prostate cancer is PSMA positive.

Is there any prep for a PSMA PET scan?

A doctor will tell you how to prepare for a PSMA PET scan. Some general requirements may include eating a limited carbohydrate diet for the 24 hours before the PSMA PET scan and not eating or drinking anything except water within 6 hours. A doctor will tell you whether to not take any medications you regularly take.

The PSMA PET scan is an imaging test that can help your doctor learn whether prostate cancer has spread beyond your prostate gland to other parts of your body or returned following successful treatment.

Research suggests the PSMA PET scan is more accurate than conventional tests for diagnosing metastatic prostate cancer. It could help your doctor develop an accurate diagnosis and the most effective treatment for your condition.

This scan may not be available in all regions or covered by all insurance plans.

Talk with your doctor to learn the types of tests you need, where you can access these tests, and whether they are covered by your insurance plan if you have one.