Positron Emission Tomography/Computed Tomography (PET/CT)


Positron Emission Tomography/Computed Tomography (PET/CT)

Northwestern Medicine patient laying down in PET CT scanPositron emission tomography—computed tomography (PET/CT) provides highly detailed images that can help fine-tune a diagnosis for cancer, heart disease or brain disorders. 

At Northwestern Medicine, you’ll find the most current advances in PET/CT along with board-certified radiologists* and licensed technologists to guide your exam. PET/CT exams are performed in a convenient, comfortable outpatient setting.

How PET/CT works

PET/CT is a diagnostic imaging tool that combines two scan techniques: positron emission tomography (PET) and computed tomography (CT). It uses a small dose of radiation to create detailed images of structures and functions inside your body and can detect problems that don’t show up on other types of diagnostic imaging exams.

  • Computed tomography (CT or CAT scan): CT is a noninvasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce both horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs.
  • Positron emission tomography (PET): PET is a specialized radiology procedure used to examine various body tissues to identify certain conditions. PET may also be used to follow the progress of the treatment of certain conditions. PET is a type of nuclear medicine procedure. This means that a tiny amount of a radioactive substance, called a radionuclide (a radiopharmaceutical or radioactive tracer), is injected into the body during the procedure to assist in the examination of the tissue under study. A special type of camera can then detect the radioactivity in the body.

How PET/CT is used

Physicians use PET/CT in many ways:

  • To detect cancers and assess the effect of cancer therapy
  • To diagnose heart disease and gauge heart muscle damage after a heart attack
  • To examine the brain for people with specific brain disorders

About your exam

During a PET/CT scan, you are first injected with a radioactive substance. Lying on a flat table, you move slowly through a doughnut-shaped machine that detects positrons, tiny particles given off by the radioactive material. The machine takes a series of thin "slice" images, which are then assembled to create a three-dimensional image of your body.

A radiologist will interpret results of your exam and report them to your physician. PET/CT scanning is provided on an outpatient basis.

Locations & Contact Information

    Related Resources

    Northwestern Medicine Cancer Center Warrenville: PET/CT Scan Instructions 


    In the spirit of keeping you well-informed, some of the physician(s) and/or individual(s) identified are neither agents nor employees of Northwestern Memorial HealthCare or any of its affiliate organizations. They have selected our facilities as places where they want to treat and care for their private patients.