General PET/CT

What is Positron Emission Tomography?

Positron emission tomography, also called a PET scan, is a nuclear medicine exam that produces a three dimensional image of functional processes in the body. A PET scan uses a small amount of a radioactive drug to show differences between healthy and diseased issue. The diagnostic images produced by PET are used to evaluate a variety of diseases.

What are some common uses of PET?

• Detect cancer
• Evaluate the heart for:
  • Blood flow
  • Signs of coronary artery disease
  • Heart function
• Evaluate the brain for:
  • Memory disorders
  • Brain tumors
  • Seizure disorders

How should I prepare for this procedure?

PET is usually done on an outpatient basis. You should:

• Wear comfortable clothes
• Not eat for four to six hours before your scan
• Drink plenty of water
• Consult with your doctor regarding the use of medications before the test
• Inform your doctor or scheduler if you have diabetes or high sugar levels.

What should I expect during this procedure?

• You receive an intravenous (IV) injection of the radioactive substance. However for some patients, you may be asked to inhale the substance as it is inserted.
• The radioactive substance will then take approximately 30 to 90 minutes to travel through your body and be absorbed by the tissue under study. During this time, you will be asked to rest quietly and avoid significant movement or talking, which may alter the localization of the administered substance.
• You will be positioned on the PET scanner table and be asked to lie still during your exam.
• Scanning takes 30 to 45 minutes.
• Some patients who are being evaluated for heart disease may undergo a stress test in which PET scans are obtained while they are at rest, and again after undergoing the administration of a pharmaceutical to alter the blood flow to the heart.
• Usually, there are no restrictions on daily routine after the test. You should drink plenty of fluids to flush the radioactive substance from your body.

What will I experience during the procedure?

• If given an intravenous injection, you will feel a slight prick. However, you will not feel the substance in your body.
• You will be made as comfortable as possible on the exam table before you are positioned in the PET scanner for the test.
• You will hear buzzing or clicking sounds during the exam.
• Patients who are claustrophobic may feel some anxiety while positioned in the scanner.
• Some patients find it uncomfortable to hold still in one position for more than a few minutes.

For more information on this topic, please visit www.Radiologyinfo.org.

Cardiac PET

What is Cardiac PET?

Cardiac PET scanning is generally similar to other types of non-invasive stress tests to help determine the presence and extent of CAD. A positron emission tomography (PET) scan is a unique noninvasive imaging technique that can produce three-dimensional images of the living heart, brain or other organs at work. It has two major advantages over the more common nuclear stress tests. First, the images are less likely to be distorted by parts of the patient’s body (large breasts, obesity etc.), so abnormal results are more reliable. Second, it is an excellent tool for determining whether portions of the heart muscle are still living and functioning. The scan can also measure how well those viable portions are functioning after a heart attack or other event in which there is a lack of oxygen-rich blood to the heart muscle.

What are some common uses of this procedure?

Clinical studies show an important role for PET in diagnosing patients, describing disease and developing treatment strategy. PET is the most accurate test to reveal coronary artery disease and impaired blood flow or rule out its presence. PET is the gold standard to determine the viability of heart tissue for revascularization. PET can determine whether bypass surgery or transplant is the appropriate treatment

What should I expect during this exam?

After reviewing your history and any prior exam, you'll receive a radiopharmaceutical injection. This is a radioactive tracer that must pass multiple quality control measures before it is used for any patient injection. The radiopharmaceuticals used for this exam administered just before scanning begins.

When you're ready for scanning, you'll lie on a comfortable table that moves slowly through the ring-like PET scanner as it acquires the information it needs to generate diagnostic images. You will be asked to lie very still, because movement can interfere with the results.

You shouldn't feel a thing during the scan, which can last anywhere from 15 to 60 minutes. Then, unless the physician sees a need for acquiring additional information, you will be free to leave.