PET/CT scan is a type of imaging test that combines positron emission tomography (PET) and computed tomography (CT) techniques. Combined PET/CT scans can be performed on any part of the body.

PET scans use a radioactive tracer that is introduced into your body to measure the cellular activity of the cell type or body part being scanned. A CT scan takes a large number of x-rays. These are analyzed by a computer to create a 3-dimensional image of the body part being studied. When both tests are performed at the same time, the information about function and structure is integrated through computer models.

PET Scan of the Brain
PET scan head brain
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Possible Complications

Some possible complications with this test include:

  • Allergic reactions to the chemicals used
  • Kidney damage from the contrast chemical used
  • Long-term effects from radiation exposure



This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.


Clinical Center—National Institutes of Health 

Radiology Info—Radiological Society of North America 


Canadian Cancer Society 

Public Health Agency of Canada 


PET/CT scan. Hartford Hospital website. Available at: Accessed February 16, 2016.

Positron emission tomography-computed tomography (PET/CT). Radiological Society of North America Radiology Info website. Available at: Updated June 11, 2013. Accessed February 16, 2016.

Schidt GP, Kramer H, et al. Whole-body magnetic resonance imaging and positron-emission tomography-computed tomography in oncology. Topics in Magn Res Imaging. 2007;18:193-202.