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. This procedure adds to a physician’s ability to better diagnose and manage disease.

 
Combined, PET/CT help pinpoint cancer anatomically.

 
[CT Scan (left) shows the anatomy. PET scan (right) shows increased cellular activity indicating cancer.]

 
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

Please follow these instructions in preparation for your PET/CT:

• No strenuous exercise 24 hours before your exam.
• Wear metal-free, comfortable clothes.
• Take any prescribed medications on the day of your exam (you may use water to take this medication) unless instructed not to do so by your physician.
• Leave valuables at home.
• Arrive 45 minutes BEFORE your scheduled exam time to register, change clothing (if necessary) and complete a pre-screening questionnaire with the technologist who will perform the procedure.
• Bring your insurance card with you.

Can I Eat or Drink Before Exam?

You will be asked drink plenty of water on the day of your exam and have no food or drink (except water) for 6 hours before your appointment time. This includes no gum chewing, hard candy or mints the morning of the exam.

If you are a diabetic, please fast for at least 4 hours prior to the PET/CT except for CLEAR water.

How Long Will the Exam Take? 

Most patients can expect to be at the hospital for between 2-2 ½ hours for the test.

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 45 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.