A PET scan is a diagnostic tool that allows Dr. Diego to check for heart disease or problems with blood flow in the heart.

PET (or positron emission tomography) is a nuclear imaging test. It involves injecting a radioactive substance called a tracer into the blood stream. The tracer collects in organs and tissues, including the heart. A PET scanner registers signals from the tracer and feeds them to a computer, which then composes a three-dimensional image of the moving heart.

The amount of radioactivity in the tracer is very small and is usually flushed out by the kidneys within 24 hours. Viable tissue (that is, muscles, for instance, which are working) will take up more of the radioactive substance than non-functioning muscle. This allows the doctor to assess any damage to the heart or scar tissue.

Unlike MRI and CT scans, a PET scan shows the organs and blood in action. This enables Dr. Diego to also see which areas of the heart may not be getting an adequate blood supply, which could mean that the patient has already suffered a heart attack.

The PET scan is painless and non-invasive. The patient is asked to lie down on a narrow table. Electrodes for an EKG are placed on the chest, and the table is slid into a tunnel-like scanner.

This test can show the size, shape, position and some functions of the heart.

The doctor may want the patient to have one scan taken during rest, and another scan taken while the patient is exercising. The exercise component is called a stress test, and it allows the doctor to see the effects of physical activity on the heart and blood flow.

The doctor will ask for a PET scan if he needs more information on any of the following:

  • Coronary artery disease
  • Damage due to a prior heart attack
  • Whether the patient might benefit from certain treatments such as angioplasty

The patient is asked not to eat for four to six hours before the scan. (Water is allowed, but no caffeine or alcohol.) The patient should tell the doctor about any medications he or she is taking, including any herbal or nutritional supplements. If the patient has diabetes and is taking insulin, the dosage may need to be adjusted.

The procedure usually takes between one and three hours. Women who are pregnant or nursing an infant should not take a PET test.