In gastroenterology, capsule endoscopy is a gastrointestinal endoscopy that "non-invasive, endoscopic imaging by use of video capsule endoscopes to perform examination of the gastrointestinal tract, especially the small bowel."
The core technology is a video camera and lights that transmit to antennas wrapped around the body. Beyond this, however, newer capsules contain accelerometers and gyroscopes that can time and track its passage through the body.  Later devices are controllable as to position with an external magnetic field, so the examiner can give a detailed look to an area of interest. This control mechanism draws from robotic navigation systems used in invasive cardiology.
Position information can be acquired by a number of methods, although the more precise ones present a hazard of ionizing radiation.
- two-dimensional triangulation of the radio signal from the capsule and possibly inertial navigation
- fine two- and three-dimensional positioning aided fluoroscopic imaging.
It can examine parts of the small intestine not reachable by other internal viewing methods.
Potentially, the ability of the capsule to track its speed and direction, when not under external control, can provide information on gastrointestinal mobility at a level not available from other modalities.
It is possible that a partial occlusion of the gastrointestinal tract could entrap the capsule. This is not a risk with virtual colonoscopy, and, with traditional colonoscopy, the examiner could recover immediately.
- Anonymous (2019), Capsule endoscopy (English). Medical Subject Headings. U.S. National Library of Medicine.
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