By the way, doctor: Colonoscopy: Is it time to go virtual?
Q. I read that President Obama had a virtual colonoscopy. Is this the colon cancer screening test that everybody should be getting instead of a regular colonoscopy? I thought it was kind of experimental.
A. You're right about the president having a virtual colonoscopy (which is a nickname; the more formal term is computed tomography colonography). Virtual colonoscopy isn't experimental, but it hasn't quite entered the mainstream, either. Experts have differing opinions about when and how it should be used. The American Cancer Society and other groups have endorsed it as an option for colon cancer screening, but the U.S. Preventive Services Task Force decided in 2008 that there wasn't enough evidence to recommend it. In 2009, the federal Medicare program followed the lead of the task force and decided not to cover virtual colonoscopy for routine screening.
A regular colonoscopy is done with a colonoscope, a flexible fiberoptic cable with a video camera on its tip. A cathartic — the dreaded "bowel prep" — is necessary before a regular colonoscopy because the colon needs to be free of any fecal matter for the polyps to be reliably seen. Patients need to be sedated during the exam.