A virtual colonoscopy (also known as VC or CT colonography) is an imaging procedure which uses x-rays and computers to produce 2 and 3-dimensional images of the colon and the rectum. Prior to the scan, the bowels need to prepared; then, the patient will lie on an examination table as the CT scanner takes cross-sectional images of the colon to produce a 3-dimensional image. In comparison to a normal colonoscopy, a VC is much less invasive: in a regular colonoscopy, the physician inserts a tube with a camera attached to the end into the colon. The procedure is used to diagnose colon and bowel disease, including polyps, diverticulitis and cancer. If patients report symptoms such as abdominal pain, irregular bowel habits, and bleeding from the rectum, a physician will order a VC. A VC can detect polyps and irritated tissue as well.