Understanding PET Scans: A Comprehensive Guide for Patients

If your doctor has recommended a PET scan, you might be wondering what it is and how it works. This guide will help you understand the basics of PET scans, including what they're used for, how to prepare, and what to expect during the procedure.

What Is a PET Scan?

A PET scan, short for positron emission tomography, is a type of imaging study that shows how your body is functioning. Unlike X-rays, CT scans, or MRIs, which provide images of your body's structure, a PET scan reveals how your cells are working by measuring blood flow, oxygen use, and sugar metabolism.

What Is a PET Scan Used For?

PET scans are most commonly used to diagnose and monitor various conditions, including:

• Cancer: PET scans can help doctors find cancer, determine if it has spread, check if treatment is working, and see if cancer has returned after treatment.

• Heart disease: PET scans can assess blood flow to the heart muscles, help decide the best treatment for clogged arteries, and examine the effects of a heart attack.

• Brain conditions: PET scans can be used to diagnose and monitor Alzheimer's disease, Parkinson's disease, seizures, stroke, and brain tumors.

How Do PET Scans Differ from CT and MRI Scans?

While CT and MRI scans provide detailed images of your body's structure, a PET scan shows how your cells are functioning. This is important because some diseases may cause changes in cell function before they cause visible changes in your body's structure. By detecting these changes early, PET scans can help doctors diagnose diseases that other types of imaging might miss.

Preparing for a PET Scan

Before your PET scan, be sure to inform your doctor about any allergies, health conditions, medications, or supplements you take. If you're pregnant, breastfeeding, or think you might be pregnant, let your doctor know, as the radiotracer used in the scan can harm your baby.

To prepare for the scan, you may need to:

• Avoid intense physical activity for 24 hours before the scan

• Fast and drink only water for several hours before the scan

• Remove all piercings, jewelry, and metal objects from your body

What to Expect During a PET Scan

During the procedure, you'll receive a radiotracer either by swallowing it, inhaling it, or through an injection. You'll then wait 30-60 minutes for your body to absorb the tracer before lying still on a table that moves in and out of the PET scan machine, which resembles a large, open donut.

The scan itself is painless and can take up to an hour. After the scan, drink plenty of fluids to help flush the tracer out of your body. You may need to avoid close contact with pregnant women, children, and babies for a few hours, as you'll be slightly radioactive for a short time.

PET Scan Risks and Side Effects

PET scans are generally safe, with few risks and side effects. However, some people may experience discomfort or allergic reactions to the tracer, although this is rare. The radioactive material used in the tracer is very low and will decay within a few hours or days after the scan.

PET Scan Results

A PET scan shows areas of high cell activity, which may indicate the presence of disease. Your doctor will compare your PET scan results with other imaging tests to get a more complete picture of your health. Results are usually available within 24 hours, but this may vary depending on where you have the scan done.

For more information on PET scans, consult the following reputable sources:

• Mayo Clinic - PET scan

• RadiologyInfo.org - Positron Emission Tomography - Computed Tomography (PET/CT)

• National Cancer Institute - PET Scans