This exam is usually performed by a gastroenterologist, a physician with dedicated training in the management of diseases of the gastrointestinal tract.

Preparation
As a preparation for the exam, patients must cleanse their colon of all solid foods. In order to fully cleanse the colon, patients must stop eating solid foods 1 to 2 days in advance of the test and can only drink clear fluids such as apple juice, chicken broth, lemonade, and water. Generally, bowel preparations require ingestion of several liters of laxative. Most colonoscopies are done under moderate sedation, or mild anesthesia.

Procedure

In order to conduct a colonoscopy, the doctors use a colonoscope. The colonoscope is a flexible tube that is a centimeter in diameter, that has suction, air, and a fiber optic camera. During the colonoscopy procedure the doctor will place the colonoscope in the rectum to examine the colon using a computer that is connected to the colonoscope’s camera for inflammation, bleeding, tumors, ulcers, polyps, or other types of abnormal growths. If the doctor notices any abnormalities in the colon lining during the procedure he or she may perform a polypectomy by using specialized equipment through the channels of the colonoscope to remove polyps or other growths. These specimens are then sent to a pathologist, who will examine them. Results usually arrive within 1-2 weeks after the procedure. You can find pictures of a colonoscopy here.