Numerous patients who need a screening of the colon do not go through the procedure for fear of the procedure. The colonoscopy procedure that is currently available involves inserting a flexible tube with a viewing instrument into the rectum. It requires anaesthesia and there's a remote chance that the colon wall could be perforated by the tube. However, patients now have an easier option with the discovery of a procedure called 'Virtual Colonoscopy' that doctors at the University of Michigan have been using. This procedure allows computerized scanning of the colon which is more comfortable for the patient. The patient is made to lie down in a computerized tomography (CT) scanner while a small probe is inserted into the rectum so that the colon can be inflated with carbon dioxide gas. The CT scanner then takes 3 dimensional images of the whole colon, which can then be examined for polyps. The patient does not need anaesthesia and the procedure takes only half an hour. However, the procedure is purely diagnostic and if doctors find a polyp, the regular colonoscopy procedure has to be done for removal and assessment of the polyp.