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Frequently Asked Questions Regarding PET/CT

A positron emission tomography (PET) scan is an imaging test that allows your doctor to check for diseases in your body.

What is a PET/CT scan?

A PET/CT scanner combines two powerful imaging modalities into one of the most advanced medical imaging tools available. Position Imaging Technology (PET) shows the body's metabolic activity, while the Computed Tomography (CT) shows anatomy. When fused together, the PET scan shows your body's metabolic pattern, including both normal and abnormal tissue activity (tumor), while the CT scan reveals the detailed anatomy of the area where the normal and abnormal activity is taking place.

What can a PET/CT scan tell me about cancer?

When information from a PET/CT scan is integrated, the information can be used with a high degree of confidence to detect, localize and assess the stage of a variety of cancers. A PET/CT scan may be the best available tool to diagnose the presence of cancer at an early stage and also to correctly assess the stage of disease when it is present. These factors are critically important if your doctor is to prescribe the right treatment, such as surgery, chemotherapy or radiation therapy. The combination of PET and CT is often the most accurate means of doing this. This advanced technique is also commonly used to assess how the cancer responds to this treatment.

How accurate is PET/CT scan?

A PET scan alone is very helpful in showing the presence or spread of many cancers. When combined with a CT scan in the same session, this highly sophisticated technique allows physicians to more accurately identify the precise location of the disease.

What can I expect at my PET/CT scan appointment?

Having a PET/CT scan is a non-invasive and painless process. It can be performed in less than two hours as an outpatient procedure. PET/CT scans are also useful in evaluating some brain abornmalities. For these indications, the total time required should be about an hour.

  • Step 1: Registration
    • When you arrive for your PET/CT scan, you will be registered by office personnel and taken to the imaging area where our technologists will ask you a series of questions regarding your medical history.
  • Step 2: Blood Sample
    • A small blood sample will be taken from your fingertip to check your blood-sugar or glucose level.
  • Step 3: Tracer injection
    • The technologist will inject a small amount of radioactive glucose into your bloodstream through an intravenous (IV) line. This substance is called a "tracer" and will be distributed throughout your body. It is effective and has limited side effects. Much of the tracer will be eliminated through your urine and any remaining activity in the body will decay until it is undetectable.
  • Step 4: Relax
    • After your injection, you will be asked to relax and remain relatively still for about an hour.
  • Step 5: The scan
    • During your scan, you will lie on a "scanning bed" that moves slowly through the PET/CT machine while it scans your body (20-25 minutes). You will move in steps as the PET scanner detects the injected tracer material. It is very important that you do not move or adjust your position during this time, so the two scans will be perfectly aligned. When the imaging procedure is complete, the scanner will send the resulting information to a computer that displays the PET and CT images side by side. A radiologist will review this information and provide a detailed report of the findings to your physician.

How can I prepare for my PET/CT Scan?

  • Do not perform strenuous activity for 24 hours prior to this procedure. This includes but is not limited to: running or other forms of exercise, heavy lifting, and repetitive motion. If you occupation requires a high level of activity, you may need to take off the day prior to your exam.
  • For a 24-hour period prior to your exam, limit your dietary intake of carbohydrates (sugars and starches) and drink extra fluids. Four hours prior to the scan, do not eat or drink anything except two glasses of plain water. Do not chew gum, eat hard candy or mints, or take any liquid medications including cough syrup or laxatives.
  • Diabetics will be given special instructions in advance to help make sure that their blood sugar levels are optimal on exam day. Having very high blood sugar levels may impair the accuracy of the PET/CT.
  • Wear comfortable clothing, preferably without zippers or buttons. Please do not wear jewelry. You will asked to remove your dentures, glasses and hearing aids once you arrive at the scanner.
  • Tell your physician if you are pregnant or think you may be pregnancy, if you are a nursing mother, or are claustrophobic.