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What is a PET/CT Scan?

What is a PET scan?

A Positron Emission Tomography or PET scan is a test that can help show how your tissues and organs are working.

What is a CT scan?

A Computed Tomography or CT scan uses a series of x-ray views, taken from many different angles, to look at images of your bones and soft tissue.

What does PET and CT scan look for?

At Maine Medical Center a PET/CT scan is used to look for tumors throughout the body, both cancerous and non-cancerous. At MMC, the PET scan and the CT scan are performed at the same time.

How do I prepare for a scan?

  • It is very important that you are on time for your appointment and follow these instructions. If you are late, it’s very likely that we will need to reschedule due to the pharmaceuticals involved.
  • Do not exercise 1 day before the scan.
  • Do not smoke, drink or have anything by mouth including gum, mints or cough drops 4 hours before the scan.
  • It is OK to drink plain water. This will help us get better pictures from the scan and will keep you hydrated. Do not drink any flavored water.
  • Take your medications as normal.

What if I get nervous in tight or very loud spaces?

  • There is plenty of room in the scanner and it is quiet. If you are claustrophobic, please tell your technologist prior to coming in for your appointment so that we can discuss options with you. The PET/CT scanner is deeper than a standard CT scanner so there is more room.

What should I wear?

  • Please wear warm and comfortable clothing such as sweat pants, pull-over sweatshirts, t-shirts or yoga pants.
  • Try to wear clothing that has very little metal on it like buckles and zippers.
  • Please do not wear any jewelry.

May I bring a family member or friend?

  • Yes, but the PET/CT space is a mobile unit like an RV and is very small. We will do our best to make sure your family and friends are comfortable while they wait for you.

What if I have diabetes?

If you have an early morning appointment, please eat a dinner that has a lot of protein in it, like eggs, tofu or meat. Please do not eat foods with lots of carbohydrates, like bread products and fruit. After midnight, stop eating, drinking and smoking with the exception of plain water.

  • If you have a late morning or early afternoon appointment, then please eat a light meal at least 4 hours before your appointment. Please do not eat foods with lots of carbohydrates, like bread products and fruit. If you are on insulin, please stop taking your insulin that morning or a minimum of 4 hours before your appointment.
  • If you don’t take insulin and take pills for your diabetes, then take your medications as normal.
  • Please drink 2 large glasses of water before your appointment.

What can I expect during the scan?

Once in the mobile PET/CT unit we will ask you a few questions.

  • We will then need to put an IV in your arm. If you have a mediport, we can use that.
  • We will test your sugar levels first then inject a radioactive sugar solution called fluorodeoxyglucose or FDG. After this injection we will take the IV out.
  • After the injection we have to wait 45 minutes to 1 hour for the FDG to go to the active cells in the body.
  • During the wait time we will give you a comfortable chair so that you can relax. It is important during this time that you stay still so the FDG doesn’t go to the muscles in your body.
  • While you wait you can listen to quiet music with a portable music device.
  • We ask that you do not play videos games, text, read or knit as we want you to stay very still.
  • We will ask you use the restroom before the scan.
  • A typical PET/CT scan takes about 30 minutes to complete.
  • Holding still during the scan is very important.
  • A PET/CT scanner looks very similar to a CT scanner, a round donut that a table moves in and out of.
  • You will be lying on your back and your arms will be down by your side or resting on your legs.
  • We have a strap to help support your arms, pillows to go under your knees and plenty of blankets to make you comfortable.

What can I expect after the scan?

  • After the PET/CT is complete you can go home.
  • Your scan will be read by a radiologist that specializes in looking at PET/CT scans.
  • The results will be sent to the doctor that asked for the scan.
  • If your doctor doesn’t contact you with the result within 5 business days, please contact his or her office.

How do I schedule an appointment?

  • For scheduling a PET scan, please call 396-7750, then press option 2 for radiology scheduling, and then press option 4 for PET scan or nuclear medicine study.

Please feel free to contact Nuclear Medicine with any questions at

207- 662-4311

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