Gastroenterology provides colonoscopies via GI labs located at St. Bernards Medical Center, Lawrence Memorial Hospital, and Five Rivers Medical Center. Colonoscopy is the endoscopic examination of the large colon and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis (e.g. ulceration, polyps) and grants the opportunity for biopsy or removal of suspected lesions. A colonoscopy can remove polyps smaller than one millimeter. Once polyps are removed, they can be studied with the aid of a microscope to determine if they are precancerous or not. Colonoscopy is similar but not the same as sigmoidoscopy. The difference between colonoscopy and sigmoidoscopy is related to which parts of the colon each can examine. Sigmoidoscopy allows doctors to view only the final two feet of the colon, while colonoscopy allows an examination of the entire colon, which measures four to five feet in length. Often, a sigmoidoscopy is used as a screening procedure for a full colonoscopy. Usually, some type of colon preparation, which includes a clear liquid diet and a laxative is used to cleanse your colon, so the physician is able to visualize your colon.