The word endoscopy is derived from the Greek words "Endo" meaning "inside" and "skopeein" meaning "to see". Endoscopy, a medical terminology, involves the practices carried out inside the body safely and with minimal invasion. The procedure examines the interior surfaces of the organs and parts inside the body. Now because some means was required to have a clear cut view of the inside organs of the body, so the application of fiber-optic technology was a major invention. This technique makes use of bundles of thin glass fibers for transmission of light. It works on the principle of total internal reflection to broadcast almost 100% of the light entering from one end and leaving from the other. The source of light for this “bundle of glass fiber” will be a Halogen or Xenon bulb. The current endoscope instruments come equipped with fiber bundle replaced by a miniature CCD video camera chip for transmitting signals via wires for an apparent view.

Upper GI endoscopy is a procedure using the endoscope to diagnose and, in some cases, treat problems of the upper digestive system. "Upper GI" is the portion of the gastrointestinal tract, the digestive system that includes the esophagus, the swallowing tube leading to the stomach, which is connected to the duodenum, the beginning of the small intestine. Upper GI endoscopy diagnoses hard, painful swallowing, pain in the stomach or abdomen, and bleeding, ulcers, and tumors.

Some major endoscopy types:

• Gastroscopy examines gullet, stomach and upper small intestine.
• Colonoscopy, for examining the large intestine.
• Laparoscopy for examination of the "stomach cavity" and internal organs.
• Proctoscopy, for checking piles and abnormalities of the anus and rectum.