The term “computed tomography”, or CT, refers to a computerized x-ray imaging procedure in which a narrow beam of x-rays is aimed at a patient and quickly rotated around the body, producing signals that are processed by the machine’s computer to generate cross-sectional images—or “slices”—of the body. These slices are called tomographic images and contain more detailed information than conventional x-rays. Once a number of successive slices are collected by the machine’s computer, they can be digitally “stacked” together to form a three-dimensional image of the patient that allows for easier identification and location of basic structures as well as possible tumors or abnormalities.

In cancer care, a CT scan is used to:

  • Detect or confirm the presence of a tumor
  • Provide information about the size, location, and scope a tumor
  • Guide a biopsy (the removal of cells or tissues for examination under a microscope)
  • Help plan radiation therapy or surgery
  • Determine if the cancer is responding to treatment