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Gastroscopy, (gastro- stomach; scopy-looking) is a diagnostic test that
enables the doctor to look inside of the esophagus, stomach, and duodenum.
This device has a length of approximately 1200 mm and diameter of 9.5-12.5
mm. The instrument shaft is composed of numerous specialized glass fibers
(>30,000) which allow the transmission of light down the length of each
thin fiber with minimal distortion. The multiple fiber optic images are
integrated at the proximal eyepiece unit, by means of a complex system of
lenses. The endoscopist thus views a reconstructed, mosaic image at the
proximal eyepiece (similar to a television image). Also within the
instrument shaft are several separate channels designed for passage of
optional devices such as biopsy forceps, polyp snare, cytology brush,
cautery or laser device, and suction.
Air may also be introduced for
insufflation's of the stomach. For clearing of debris from the viewing
area, a jet stream of water from a separate reservoir can be flushed
through one channel. At the head or handle of the endoscope are two
control devices ("wheels") which maneuver the instrument tip as it is
advanced, an up-down angle wheel (deflection of almost 180°) and a
right-left angle wheel (deflection of 100°). The instrument head is
connected with a separate cold light source (usually a halogen lamp) by
means of a cable comprised of incoherent fiberoptic bundles (the
"umbilical cord"). The water feed tank and automatic suction box also
attach to this cable. Optional accessories include an additional eyepiece
for simultaneous viewing by a second operator (the "teaching head"), an
ultrasound probe for real time imaging of the stomach wall, pancreas, etc,
and photographic or videotape recording devices.
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