Colonoscopy remains the best test and the current gold standard for colorectal cancer screening and prevention. While both CT colonography (virtual colonoscopy) and optical colonoscopy require the same bowel preparation, optical colonoscopy is the only diagnostic and therapeutic test that can detect and remove pre-cancerous polyps from the colon during the same office visit. CT colonography is only a diagnostic tool. If polyps are detected during a CT colonography, patients must still undergo an optical colonoscopy to have these growths removed. Since CT colonography uses X-rays to view the colon, the risk of radiation exposure has raised potential health concerns over its safety. Currently, CT colonography has not been endorsed as a colon cancer screening test and insurance companies will not pay for its use. ACG will continue to champion the lifesaving potential of optical colonoscopy. Get more information on ACG's colorectal cancer screening recommendations.