The medical team performing President Bush's colonoscopy Saturday:

Lead endoscopist: Dr. James Butler, Navy captain, chief of gastroenterology at the National Naval Medical Center, Bethesda, Md.

Lead anesthesiologist: Dr. Paul Bruha, Navy commander-select, staff anesthesiologist and assistant professor of the department of anesthesiology at the Uniformed Services University of Health Sciences, and a clinical assistant professor at the University of Maryland Shock Trauma Center.

Overseeing physician: Air Force Col. Richard Tubb, the White House physician, who also leads the 24-hour medical team stationed at the executive mansion and wherever the president travels.