PET and CT Imaging

Positron Emission Tomography (PET) and Computed Tomography (CT) are imaging tools used to pinpoint the location of cancer within the body, which adds to a physician’s ability to better diagnose and manage disease. PET/CT scans lead to earlier diagnosis, accurate staging and localization, and precise treatment and monitoring.

Positron Emission Tomography (PET) and Computed Tomography (CT) are imaging tools used to pinpoint the location of cancer within the body. This procedure adds to a physician’s ability to better diagnose and manage disease.

PET/CT detects changes in how the body functions. In one continous scan (about 30-45 minutes), PET captures images of tiny changes in the body’s metabolism caused by the abnormal growth of a tumor, while CT images at the same time allow doctors to pinpoint the exact location, size and shape of the tumor.  Essentially, tumors are detected with PET and then precisely located with CT.

Since these functional changes take place before physical changes occur, PET/CT can provide information that helps physicians make earlier diagnoses, as well as determine how current treatment is working. Even if a previous CT Scan or MRI Scan detected a problem, PET/CT can help because it may set apart or distinguish the problem earlier. As a result, PET/CT studies can lead to the start of treatment earlier and the avoidence of more invasive exams or surgery.

The Benefits of PET/CT

• Earlier diagnosis
• Accurate staging and localization
• Precise treatment and monitoring

How to Prepare for a PET/CT

Your appointment will take approximately 2½ hours.

• Non-Diabetic: No food for 6 hours prior to study.
• Diabetic: Diet Controlled /Non-Insulin and Insulin Dependent: No food for 4 hours prior to study. Diabetic medications should be taken prior to 4 hour fast.
• If you are diabetic and monitor your blood sugar you must test your blood sugar prior to going to your exam. If it is higher than 200 please call Diagnostic Imaging (802-371-4250) to inform them. All PET/CT units are equipped with glucometers to check your sugar level.
• You may take regularly scheduled medications if they can be tolerated on an empty stomach. (EXCEPT diabetic medicine.)
• You may drink clear unflavored water only. No other type of liquid is allowed.
• No caffeine, gum, cough drops or mints during the fasting period is allowed.
• You will need to be able to lay flat on your back for 25 minutes (Melanoma studies will take 60 minutes).
• If you are claustrophobic and need medication to help you relax contact your primary care physician’s office. If you take this medication, you will need a driver.
• Engage in no strenuous exercising 24 hours prior to the scan.
• Wear warm, loose-fitting, metal-free clothing (i.e. sweats, flannel shirt, etc.) The room is kept between 60-65 degrees. Please leave jewelry at home.
• We encourage you to bring as few personal items/valuables as possible.

What Should I Expect During My Exam?

Before the scan, you will be injected with a radioactive medication called a “tracer” that is tagged to sugar. You will be asked to rest quietly for about 90 minutes while the “tracer” circulates throughout your body.

The technologist will ask you to lie on the scanner table, which will slowly pass through the scanner while images are taken (one continuous scan that takes about 30 - 45 minutes). The PET/CT scanner detects the signals from your body. The signals are then put together into actual images in a computer. The Radiologist will read the images and provide your doctor with a report. Your doctor will discuss your test results with you.