What is a CT Scan?

CT scans combine a series of X-ray images taken from different angles and uses computer processing to create cross-sectional images, or slices, of the bones, blood vessels and soft tissues inside your body.

Each picture created during a CT procedure shows the organs, bones, and other tissues in a thin “slice” of the body. The entire series of pictures produced in CT is like a loaf of sliced bread—you can look at each slice individually (2-dimensional pictures), or you can look at the whole loaf (a 3-dimensional picture). Computer programs are used to create both types of pictures.

Outside of cancer, CT is widely used to help diagnose circulatory (blood) system diseases and conditions such as coronary artery disease (atherosclerosis), blood vessel aneurysms, and blood clots; spinal conditions; kidney and bladder stones; abscesses; inflammatory diseases, such as ulcerative colitis and sinusitis; and injuries to the head, skeletal system, and internal organs. CT can be a life-saving tool for diagnosing illness and injury in both adults and children.

Within cancer, CT is used to:

  • detect abnormal growths
  • help diagnose the presence of a tumor
  • provide information about the stage of a cancer
  • determine exactly where to perform (i.e., guide) a biopsy procedure
  • guide certain local treatments, such as cryotherapy, radiofrequency ablation, and the implantation of radioactive seeds
  • help plan external-beam radiation therapy or surgery
  • determine whether a cancer is responding to treatment
  • detect recurrence of a tumor
Snapshot of a CT scan demonstrating views in the Transverse (head to toe) plane, Coronal (front to back) plane and Sagittal (side to side) plane