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Positron Emission Tomography Scan


A positron emission tomography (PET) scan is used to take pictures of areas in your body. A small amount of radiation, called tracer, is put into your body before the PET scan. The tracer shows how chemicals, such as glucose (sugar), are working in your tissues. A PET scan may show an abnormal growth, such as a tumor. It may be used to show if cancer has spread. A PET scan may show disease or damage to your brain, lungs, heart, or abdomen.


The week before your test:

  • Write down the correct date, time, and location of your PET scan.
  • Ask your healthcare provider if you need to stop using aspirin or any other prescribed or over-the-counter medicine before your test.
  • Tell your healthcare provider if you are pregnant or breastfeeding.
  • Bring your medicine bottles or a list of your medicines when you see your caregiver. Tell your caregiver if you are allergic to any medicine. Tell your caregiver if you use any herbs, food supplements, or over-the-counter medicine.

The night before your test:

Ask caregivers about directions for eating and drinking.

The day of your test:

  • You or a close family member will be asked to sign a legal document called a consent form. It gives caregivers permission to do the procedure or surgery. It also explains the problems that may happen, and your choices. Make sure all your questions are answered before you sign this form.
  • You may need blood taken before your PET scan. The blood may be taken from your hand, arm, or IV.
  • Caregivers may insert an intravenous tube (IV) into your vein. A vein in the arm is usually chosen. Through the IV tube, you may be given liquids and medicine.


What will happen:

  • Tracer will be put in your IV. You will need to remain as still as possible for 1 hour as the tracer moves through your body. Healthcare providers may give you sedative medicine through your IV to help you feel calm and relaxed. You will lie on your back on a table attached to the PET scan machine. When the PET scan begins, the table will move through a large hole into the middle of the machine.
  • You will need to lie still while the scan is being done. Healthcare providers may ask you to change positions between pictures. A camera will take pictures of your head, neck, chest, or abdomen. The pictures will appear on a monitor. When the PET scan is over, the table will move out of the machine.

After your test:

Do not get off the table until healthcare providers say it is okay. You may be able to go home after the test is complete. If you are staying in the hospital, you will be taken to your room. If you are breastfeeding, do not breastfeed your child right after the test. Ask your healthcare provider how long to wait to let the tracer leave your body.


  • You cannot make it to your PET scan.
  • You have diabetes and your blood sugar is high the day before or the morning of the test.
  • Your symptoms get worse.
  • You have questions or concerns about your test.

Seek Care Immediately if

  • You have a seizure or pass out.
  • You have trouble breathing or you cough up blood.
  • You have chest pain or discomfort that spreads to your arms, jaw, or back.
  • You have nausea or you are sweating for no reason.
  • Your arm, leg, or face feels numb or weak. This may happen on only one side of your body.
  • You are confused, or you have trouble speaking to or understanding others.
  • You suddenly cannot see out of one or both eyes.


Small growths in your body may not be found with a PET scan. If the results are unclear, you may need another PET scan. The radiation from the scan may increase your risk of cancer. If you are pregnant or breastfeeding, a PET scan may harm your baby. Without a PET scan, problems with your head, lungs, heart, or abdomen may not be found. You may not get the treatment you need.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

© 2016 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.