Biophotonics_Concepts_to_Applications

Solution: (a) The peritoneal cavity contains the pelvis, stomach, spleen, gall

bladder, liver, and the intestines. Thefluid in the peritoneal cavity lubricates

the tissues and organs in the abdomen during digestion. Excessfluid in the

peritoneal cavity (for example, from a liver disease) can cause the abdomen to

swell, which can lead to breathing difficulties. (b) The most common

laparoscope is a rigid tube with a diameter of 5 or 10 mm that has a working

insertion depth of approximately 300 mm. The distal end contains imaging

lenses and the viewing end has a simple eyepiece.

10.2.1 Basic Endoscopy

The following units make up a basic endoscope system [ 16 – 21 ]:

• Aflexible tube that encapsulates one or more opticalfibers for illumination and
  viewing functions. As Fig.10.9illustrates, the encapsulating endoscope tube
  also can contain miniature air, water, and suction or biopsy tubes, plus wires for
  tip control.


• An external light source that is coupled to the opticalfibers in the encapsulating
  tube for illuminating the organ, tissue area, or body cavity being diagnosed


• A lens system which collects reflected orfluorescing light from the diagnostic
  site for transmission via opticalfibers to a viewer


• A viewing mechanism such as a simple eyepiece, a monitor, or a camera
  An endoscope also can contain capillaries for collecting tissue specimens,
  miniature manipulative tools for microsurgery, or more opticalfibers for therapeutic
  purposes. Traditionally endoscopes have used a smallflexible opticalfiber bundle
  to transmit light to a diagnostic area and a coherentfiber bundle for image retrieval.
  Although the use offiber bundles results in a noninvasive exploratory instru-
  ment, the number of individualfibers in the bundle and their characteristics limit the
  image resolution and can increase the outer diameter of the instrument [ 21 ]. The

Single fibers

or fiber bundles

for viewing

Water tube

Air tube

Biopsy or

suction channel

Illuminating fiber

Flexible

outer tube

Tip control wires

Fig. 10.9 Cross-sectional view of a generic endoscope tube showing various possible optical
fibers, miniature tubes, and wires for different functions (J. Biomed. Opt. 19(8), 080902 (Aug 28,
2014). doi:10.1117/1.JBO.19.8.080902)

304 10 Optical Imaging Procedures