What is a PET scan?
A PET (positron emission tomography) scan is a procedure used to
observe the brain, the heart, or tumors. You will be given an
injection of a low-level radioactive material attached to a
natural body chemical. The scan shows where the radioactive
material went and how much of it the brain, heart, or tumors are
using.
When is it used?
The doctor may order this procedure to find:
- early coronary artery disease
- damaged or scarred heart muscle (as a result of a heart
attack) that might be improved with surgery
- the effect of drugs on the heart and brain
- early brain changes and diseases such as Alzheimer's disease,
Parkinson's disease, or epilepsy
- the cause of mental disorders, such as schizophrenia
- abnormal tissue or tumors
- shifts in blood flow
- areas affected by a stroke or blood clot.
Other tests such as CT scans, stress tests, or X-rays may also be
used. Ask your provider about which tests are best for you.
How do I prepare for a PET scan?
Follow the doctor's instructions. The night before the procedure,
eat a light meal such as soup and salad and do not eat or drink
anything the morning of the procedure. Eating affects blood sugar
(glucose) levels. The blood glucose level needs to be less than
200 at the time of the scan. PET scan test results will not be
accurate if blood glucose levels are too high.
What happens during the procedure?
The PET technologist will inject a low-level radioactive material
and a natural body compound (most commonly glucose, but sometimes
water or ammonia) into your vein. The PET scanner has a hole in
the middle and looks like a large doughnut. You will lie down on
an examining table that slides into the PET scanner. You will be
asked to rest quietly and try not to move or talk. The
technologist will then take pictures that help the doctor
understand the health of the organs scanned.
What happens after the procedure?
The PET technologist will send the complete report to the doctor,
who will interpret the results.
You should drink plenty of fluids to flush the radioactive
substance from your body. Ask your doctor what other steps you
should take and when you should come back for a checkup.
What are the benefits of this procedure?
This procedure will help the doctor make a more accurate
diagnosis.
What are the risks associated with this procedure?
You may have an allergic reaction to the chemical used in the
scan. Ask your provider how this risk applies to you.
When should I call the doctor?
Call the doctor during office hours if:
- You have questions about the procedure or its result.
- You want to make another appointment.
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change as new health information becomes available. The
information is intended to inform and educate and is not a
replacement for medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
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This
information is approved and/or reviewed by U-M Health System providers
but it is not a tool for self-diagnosis or a substitute for medical
treatment. You should speak to your physician or make
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this information or your medical condition.