How It Feels

You will not feel pain during the test. The table you lie on may be hard and the room may be cool. It may be difficult to lie still during the test.

You may feel a quick sting or pinch when the IV is put in your arm. The tracer may make you feel warm and flushed. Some people feel sick to their stomach or have a headache. Tell your doctor how you are feeling.

You may feel nervous inside the PET scanner.

Risks

There is always a slight chance of damage to cells or tissue from radiation, including the low levels of radiation used for this test. But the chance of damage is usually very low compared with the benefits of the test.

Most of the tracer will be flushed from your body within 6 to 24 hours. Allergic reactions to the tracer are very rare.

In rare cases, some soreness or swelling may develop at the IV site where the radioactive tracer was put in. Apply a moist, warm compress to your arm.

Results

Positron emission tomography (PET) is a test that uses a special type of camera and a tracer (radioactive chemical) to look at organs in the body.

The radiologist may discuss preliminary results of the PET scan with you right after the test. Complete results are usually available in 1 to 2 days.

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What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Being pregnant. A PET scan is not usually done during pregnancy because the radiation could harm the unborn baby (fetus).
• Using caffeine, tobacco, or alcohol in the past 24 hours.
• Not being able to lie still for the test.
• Being too anxious.
• Using sedatives.
• Taking medicines, such as insulin, that change your metabolism.
• Having recently had surgery, a biopsy, chemotherapy, or radiation therapy.