Positron Emission Tomography (PET)


PET scans combine the principles of nuclear medicine with computer technology to find “hot spots” that can indicate areas of disease.

Positron Emission Tomography | El Camino Health

Positron Emission Tomography

Like other nuclear medicine tests, PET uses a small amount of a radioactive substance to examine the structure of tissues and organs and their functioning.

Your PET scan will follow these steps:

  • You’re given the radiotracer by mouth, injection or inhalation, depending on the test, and you’ll wait while the radiotracer accumulates in the area to be examined — usually about an hour.
  • You lie on a narrow table that slides into the scanner, which is shaped like a short tunnel. It’s important to stay very still while the scanner detects signals from the tracer.
  • A computer translates the signals into 3D images. A radiologist examines them and sends a report to your doctor.

PET scans are often used in conjunction with CT scans or other imaging tests to get more information about a specific organ or tissue area. When PET is combined with CT in one scan, it is known as PET/CT.

Doctors may recommend a PET scan to:

  • Determine if cancer has spread or recurred, or to evaluate the progress of cancer treatments.
  • Evaluate the brain after trauma.
  • Diagnose dementias such as Alzheimer’s disease.
  • Diagnose neurologic conditions such as Parkinson’s disease or epilepsy.
  • Evaluate the blood flow in the heart.
  • Evaluate brain tumors.