Computed tomography, or CT for short, is a special x-ray examination (the ancient Greek tome means “slice”, and Greek graphein means “to write”). The person being examined lies down and is then moved through a ring-shaped CT scanner. An x-ray source in the CT scanner rotates around the selected body region and its density is measured from various directions. A computer puts this data together and generates a multidimensional cross-sectional image of the body region examined. As in any other x-ray examination, people who have a CT examination are exposed to radiation.