Gastroscope, << GAS truh skohp, >> is an instrument used by physicians to examine the inside of the stomach. Because physicians also use it when examining the esophagus and the duodenum (upper part of the small intestine), it is often called an upper endoscope.
A gastroscope consists of a long, flexible tube and a rigid metal section that has a lens and various controls. Two bundles of long, thin glass threads called optical fibers extend along the inside of the tube.
The physician lowers the tube through the mouth and esophagus and into the stomach. Light travels through one of the bundles of optical fibers and strikes the wall of the stomach. The fibers in the other bundle absorb the light after it is reflected off the stomach wall. They produce an image of the illuminated part of the stomach by transmitting this light to the lens of the gastroscope. The doctor sees the image through the lens.
Physicians use a gastroscope to determine the cause of internal bleeding and to help diagnose cancer. A gastroscope can be fitted with attachments to view tumors and ulcers, to cut out growths called polyps, or to remove objects that have been swallowed. Other types can guide a laser used to destroy tumors in the esophagus or to stop bleeding in the stomach or intestine. Another type of gastroscope has a miniature video camera in its tip.
