Positron emission tomography/computed tomography (PET/CT) is imagining technology that combines the benefits nuclear medicine and computerized X-rays. The PET scanner shows how cells are functioning (metabolism), while the CT scanner shows detailed anatomy and location.

PET/CT scans, which are most often used to diagnose cancer, can help:

  • Detect cancer and learn its stage.
  • Find the right place for a biopsy.
  • See how well cancer treatments are working.
  • Plan radiation therapy.
  • PET/CT scans are also used to diagnose heart disease and brain disorders.

How does a PET/CT work?

Like other nuclear medicine scans, positron emission tomography/computed tomography procedures use very small amounts of radioactive material called radiotracers to see inside the body. Before the test begins, a technologist or nurse will insert an IV to administer the radiotracers. You may then need to rest for 30 to 90 minutes to allow the radiotracers time to reach the tissues that will be scanned.

The PET/CT scanner looks like a large donut with a flat table in the middle. You will lie on the scanner table, which may have pillows, straps or a cradle for your head. Your position on the table will depend on what part of your body is being scanned, but most patients lie on their back.

All you need to do is relax and lie quietly. When the positron emission tomography/computed tomography scan starts, the table will slide quickly through the hole in the center to make sure you are in the right position. Then the table will slide slowly back and forth. The technologist may also raise or lower the table, or tilt the scanner to get pictures from different angles.

After the procedure, the Mercy technologist will answer any questions you may have. A Mercy radiologist will review your images and report the findings to your doctor within a few hours.

Locations Nearby

Mercy Hospital Jefferson

  • 1400 Highway 61 South
    Festus, MO 63028
  • (636) 933-1000
  • Hours of Operations:
    Open daily 24 hours.
97 Miles

Mercy Imaging Services - Washington

  • 851 E. Fifth Street
    Washington, MO 63090
  • (636) 239-8255
  • Hours of Operations:
    Monday-Thursday: 6:30 a.m. - 5 p.m.
125.4 Miles

David C. Pratt Cancer Center

  • 607 S. New Ballas Road
    Saint Louis, MO 63141
  • (314) 251-4800
  • Hours of Operations:
    Monday-Friday: 8 a.m. - 4:30 p.m.
127.8 Miles

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