What It Is, Types, Purpose, Procedure & Results

What is a PET scan?

A positron emission tomography (PET) scan is an imaging test that produces images of your organs and tissues at work. The test uses a safe, injectable radioactive chemical called a radiotracer and a device called a PET scanner.

The scanner detects diseased cells that absorb large amounts of the radiotracer, which indicates a potential health problem.

Healthcare providers frequently use PET scans to help diagnose cancer and assess cancer treatment. They can also assess certain heart and brain issues with the scan.

What’s the difference between a PET scan, CT scan and MRI?

Computed tomography (CT) scans use X-rays. Magnetic resonance imaging (MRI) scans use magnets and radio waves. Both produce still images of organs and body structures.

PET scans use a radioactive tracer to show how an organ is functioning in real time. PET scan images can detect cellular changes in organs and tissues earlier than CT and MRI scans. Your healthcare provider may perform a PET scan and CT scan at the same time (PET-CT). This combination test produces 3D images that allow for a more accurate diagnosis.

Some hospitals now use a hybrid PET/MRI scan. This new technology creates extremely high-contrast images. Providers mainly use this type of scan for diagnosing and monitoring cancers of the soft tissues (brain, head and neck, liver and pelvis).

What does a PET scan check for?

Your healthcare provider may order a PET scan to check for signs of:

When would I need a PET scan?

In general, a PET scan can measure vital functions, such as blood flow, oxygen use and blood sugar (glucose) metabolism. It can also identify organs and tissues that aren’t working as they should.

If your healthcare provider suspects you may have cancer, they’ll likely recommend a PET scan, which can detect cancer and/or make a diagnosis.

If you’ve already been diagnosed with cancer, your provider may recommend more than one PET scan throughout your treatment to:

• Determine whether the cancer has spread in your body (metastasized).
• Assess the effectiveness of treatment.
• Determine if the cancer has returned after treatment (recurred).
• Evaluate the prognosis (outlook) of the cancer.

If you’re having heart issues, your provider may recommend a PET scan to:

• Determine the effects of a heart attack on areas of your heart.
• Identify areas of the heart muscle that would benefit from angioplasty or coronary artery bypass surgery.

If you’re experiencing neurological symptoms, your provider may recommend a PET scan to evaluate possible brain abnormalities, such as tumors, seizures and other central nervous system conditions.