PET Scanning

Your doctor has requested a PET (positron emission tomography) scan for you. For this examination, we attach a radioactive molecule to your glucose (sugar).

Glucose is a major source of energy in the body. But, certain disease processes make use of a much greater level of glucose than normal tissue.

The PET scan allows us to take pictures to reveal areas of abnormal glucose uptake. This procedure causes no side effects and provides only a small dose of radiation.

The PET scan procedure

Before your scan

Before the scan, we get information about the reason for the scan and your medical history. Your doctor provides much of this information. But, we may ask you questions when you arrive about your medical history, allergies, and medications. It is also essential for us to know if you have diabetes.

We must also have your other studies for comparison. These may be X-rays, computerized tomography (CT) scans, or magnetic resonance imaging (MRI) scans. If Dartmouth Hitchcock Medical Center and Clinics performed your exams, we have access to your studies. If you had your studies performed elsewhere and you have access to them, please bring them with you. We will use them as we read your PET scan and then return them by mail either to you or to the lending institution. If there are copies, we can keep them on file here. Please let us know if this is possible.

Before your scan:

  • Avoid any strenuous exercise for 24 hours.
  • Do not eat anything for six hours.
  • Please take any prescribed medication (you may use water to take this medication).

If you are to receive a CT scan with oral contrast administered within 6 hours before the PET scan, use a sugar-free contrast.

For diabetic patients

If you have diabetes, we will send you instructions in advance with your appointment letter.

After checking in at the Nuclear Medicine reception desk, we take you to a preparation area. We check your blood glucose level with a fingerstick. In rare instances, it may be necessary to postpone or cancel a test if your blood glucose level is abnormal.

  • We place an intravenous line usually in your arm.
  • We then take you to the PET holding area.
  • We place you in a chair and administer the radioactive glucose through the IV line. You will not feel anything or have any reactions or side effects.

You will then sit in a recliner for 60 minutes. You may not get up, talk, read, or chew gum. You must sit quietly and not get up because motion causes the accumulation of glucose in the muscles, which can degrade the quality of the scan. After this, we will take you to a bathroom where you can empty your bladder and then we bring you to the scanner.

The PET scanner is a ring-shaped device, similar in appearance to a CT scanner. If you have or expect any problems with claustrophobia, please let us know as soon as possible. You will lie still on the PET scan table for 20 to 30 minutes. Following this, we review the scan for quality. In a few instances, we may take more pictures. Upon completion of the study, we remove the IV.

After your scan

After the study, we ask that you avoid close contact with children and pregnant women for eight hours.

Please do not hold a child or have them sit on your lap for more than a couple of minutes. If you are breastfeeding, please stop for eight hours.

Note: We are very cautious in this regard. There are no definite risks from this level of radiation.

Scan results will not be available while you are in the department. We will send the interpretation of the study to your doctor who has requested the test.

If you have brought any other scans to the department, we request that you leave them with us with instructions on where to return them.