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What is PET/CT?

Positron Emission Tomography/Computerized Tomography (PET/CT) is an imaging test that produces high resolution pictures of the body's biological functions and anatomic structures. These images show body metabolism and other functions rather than simply the gross anatomy and structure revealed by a standard CT or MRI scan. This is important because functional changes are often present before obvious structural changes in tissues are evident. PET/CT imaging can uncover abnormalities that might otherwise go undetected. For example, PET/CT can determine the presence and extent of tumors unseen by other imaging techniques, or detect Alzheimer's disease one to two years before the diagnosis would be made with certainty by your primary doctor.

Diseases for which PET/CT is most commonly used:

  • Cancer
  • Alzheimer's Disease
  • Coronary Artery Disease
  • Epilepsy

How accurate is PET/CT?

PET/CT is believed to be the most accurate imaging test available to evaluate lung cancer, colon cancer, breast cancer, melanoma, lymphoma, head and neck cancer, and esophageal cancer. In published research studies, PET has been shown to have an approximately 90% accuracy in many of these cancer types. PET is the most accurate imaging test available to determine the presence of a dementia process such as Alzheimer's disease. PET is also the most accurate test available to evaluate patients who have had a previous heart attack and are being considered for a procedure to improve blood flow to the injured heart muscle.

PET/CT assists physicians and patients in the management of cancer by:

  • Assessing the location and extent of cancer prior to surgical or radiation treatment
  • Serving as a test for early detection of recurrent cancer
  • Monitoring the effect of treatment non-invasively
  • Reducing or eliminating ineffective and unnecessary treatment

• Replacing multiple medical testing procedures with a single exam

Who should not have a PET/CT scan?

  1. Pregnant women should consult their doctor before having this scan.
  2. Patients who have severe kidney problems or who are allergic to iodine can have a PET/CT without the I.V. contrast.
  3. An itching sensation or shortness of breath may indicate an allergic reaction to the contrast. Please let your technologist know if you have any allergic reaction.

How does the procedure work?

  1. You will be asked to drink approximately 3 cups of oral contrast.
  2. Shortly after, you'll be injected with a radioactive sugar isotope solution.
  3. You will then rest comfortably for approximately 45 minutes while the sugar distributes throughout your body.
  4. Before you get positioned on the scanner, you will have a chance to visit the restroom and change into a gown.
  5. You will be scanned for approximately 30 minutes and may receive additional I.V. contrast depending on your physician's request.  Normal reactions when getting I.V. contrast may include flushing, nausea, headache or a salty taste in your mouth.

What should I do to prepare for the procedure?

  • On the day of the scan take your regularly prescribed medications with water only.
  • Do not eat or drink anything except water for four to six hours before the scan.
  • Diabetic patients should schedule their scan so that their last dose of insulin or diabetic medication is at least two hours prior to the procedure.
  • Refrain from heavy exercise for 12 hours prior to the scan.
  • Drink at least two glasses of water one hour before the scan.

How will I feel after the exam?

You should feel fine. You may resume your normal activities and eat a regular meal immediately following the scan.

How much time should I allow?

Most patients will be in the clinic for approximately two to two and a half hours.

When will I know the results of my PET/CT Scan?

Your referring physician will have the report 24 to 48 hours after the exam.