Shared Medical Services What is CT?

What is CT? | FAQs and links

What does CT stand for?

CT stands for computed, or computerized, tomography.  It is also sometimes called a CAT scan, or computed axial tomography.

What is the purpose of a CT scan?

  • Diagnose muscle and bone disorders, such as bone tumors and fractures
  • Pinpoint the location of a tumor, infection or blood clot
  • Guide procedures such as surgery, biopsy and radiation
  • Detect and monitor diseases such as cancer or heart disease
  • Detect internal injuries and internal bleeding

What is contrast, and what purpose does it serve in a CT scan?

Contrast is an iodine dye that is sometimes administered prior to a CT scan.  It can be given orally, through an IV, or by enema.  It is used to highlight organs and structures with more image contrast to better show disease, injury, or abnormalities.  It can also be used to check blood flow, find tumors, or look for other problems. 

How much radiation are you exposed to during a CT scan, and is it harmful?

A CT scan does use a higher amount of radiation than an X-ray, but both are strictly monitored and controlled to ensure they use the least amount of radiation as possible.  CT scans create low levels of ionizing radiation, which could potentially cause some health issues, but it is generally kept at a safe level.  Most feel that the information a CT scan provides outweighs the risks associated with the minor radiation exposure.

What other risks are there with a CT scan?

  • If you are pregnant, having a CT scan could cause harm to the fetus due to the radiation exposure.  Most doctors will discourage having a CT scan during pregnancy.
  • Having asthma or allergies creates a slight risk of having an allergic reaction to the contrast medium.
  • Other medical conditions, such as diabetes, asthma, heart disease, kindey problems, and thyroid conditions, also increase the risk of an allergic reaction to the contrast medium. 



Radiology Info

Medline Plus

National Cancer Institue

American Cancer Society

eMedicine Health



Wondering what your doctor will be reviewing? Click below on a thumbnail to view an actual CT scan.