Laparoscope Video Imaging - Matthew Butler PGY 4 General Surgery Clifford B. Sample Clinical Assistant Professor University of Alberta

Laparoscope Video Imaging
                Matthew Butler
         PGY 4 General Surgery

                Clifford B. Sample
      Clinical Assistant Professor
              University of Alberta

Objectives
 • Laparoscopic Video Imaging
    •   Light Source/Cable
    •   Endoscope
    •   Camera
    •   Video Processor
    •   Display
 • Troubleshooting and Practical aspects
 • Integrated OR

Light Source
• A good light source is
  necessary for safe
  laparoscopic surgery
• Image quality depends on
  light
   • Quality
   • Quantity
• Consists of
   •   Lamp/bulb
   •   heat filter
   •   condensing lens
   •   Manual or automatic
       intensity control circuit

Light Source
• Xenon and Halogen are most
  common type of bulbs used
  today
   • High intensity
   • Closest to pure white light
• Still need white balance every
  time as spectrum changes
  over time

Light Cables
• Fiber optics invented in 1954
• Based on principle of total internal reflection
• Allows for transmission of light from source to
  destination where no straight path exists.
• Up to 90% light loss from cable

Light Cables
• Main problem with fiber optic cables is their fragility and
  susceptibility to damage with excessive manipulation
    • Direct impact
    • Major twisting (being rolled too tightly)
    • Crushing

• To prevent
    • Handle carefully
    • Don’t wind tighter than
      radius of 15cm

Troubleshooting – Light and Cable
• First check all connections
• Blurry Image
   • Can be due to insufficient light as cameras sharpness
     degraded with less light
• Too Close
   • Surgeon will compensate for an insufficient light source
     by moving the camera closer. This interferes with
     operative maneuvers and makes things difficult
• Blood!!!
   • HgB absorbes light
   • If not enough light to overcome this things begin to look
     dark

Camera
 Consists of
     •   Photo CCD (charged coupled device)
     •   Lens and focusing ring
     •   Coupling mechanism
     •   Water resistant casing

CCD (Image Sensor)
• Fancy device that converts a visual image to electrical
  signals
• Same technology in consumer digital cameras
• Quality of image depends on
    • Resolution of CCD (how many pixels it captures)
        • Newest are HD (1920×1080, or 2,073,600pixels)
    • Type of CCD
        • 3 chip system is far superior

Lens and focus ring
 • Lens is placed between the endoscope and the CCD
 • Focus ring allows change in the distance between the
   lens and the CCD
    • Optical focus

Camera Control Unit
 • Once the image signal has been created, it is sent to
   the camera control unit where it is processed, amplified
   and sent to a video output

Video Output
 Composite Video

 S-Video
     • Older technology, better than composite

 Component Video
     • Separate cable for RGB
     • Supports high resolution but still analogue

 Digital (DVI)
     • Digital signal transmission
     • No distortion of signal loss
     • Supports highest resolutions

Troubleshooting - Camera
 No image
    • Camera not plugged in or switched on, connections
      loose, defective cabes, light source not attached, monitor
      not connected
 Color problems
    • Usually a cable problem, connection or faulty cable
    • Faulty white balance
 Image too dark
    • Defective endoscope
    • Cable problem (light or video)
    • Bleeding

Troubleshooting - Camera
 Graininess/noise
    •   Gain enhancement
    •   Electrical interference

 Image not centered
    •   Coupling ring

 Blurry Image
    •   Focus, clean scope

Endoscope
 Ideal characteristics
     •   Brightness
     •   Minimal Distortion
     •   Adequate Depth of field
     •   Durability

Endoscope - Structure
  Rigid tube containing 2 channels
     • Light channel
     • Image channel
         • Multiple lenses separated by spacers, each inverts the
           image
         • Inverting Real Image Lens System (IRILS)
         • Eyepiece lens magnifies the image and directs it back to the
           endoscope

Endoscope
  Focal length
      • Focal length depends on the aperture at the end of the
        laparoscope
      • Image appears normal size at the focal length and is
        magnified as you get closer to the image
  Depth of field
      • The distance between near and far objects which appear
        in focus
      • Narrower scopes have a greater depth of field

Endoscope
    Brightness
       • Depends on the amount of light that can be sent to and
         received from the object - affected by scope size
       • Scopes range in size from 2.5mm to 15mm
       • The bigger the brighter

Monocular Endoscopes
Angle of view
   Available in 0-120 degrees (0-45 most common)
Size
   Ranges from 3-12 mm
   Smaller scope, generally less light

Flexible Scopes
  •   Flexible tip laparoscopes have been developed
  •   Allows deflection in any direction
  •   CCD is placed in the tip of the scope
  •   Currently lower resolution, but requires less light

Troubleshooting - Endoscope
 Fogginess/loss of image
     • Endoscope too cold
     • Blood or fat dripping from trocar
     • Cold C02 blowing on scope

 Image blurry, low clarity, focusing problems
     • Check lenses at each end
     • Look through scope without camera
     • Ensure proper coupling

 Poor illumination
     Check light source connection, cables, settings
     Check for damage to light source attachment on scope
     Look for dirt or damage to scope

Monitors
 • Need a monitor with a resolution at least as great as
   the camera
 • Ideally ceiling mounted and mobile

Digital ORs
  •   Integrate equipment with a central device control, including
      potential voice activation
  •   Allow control of routes of video, including use of several
      different inputs
       •   laparoscope
       •   fluroscope
       •   endoscope
       •   PACS
       •   distant site
       •   office chart
  •   Allow control of which sources are displayed where and in
      what manner (PIP)
  •   Allows archive of images and video in digital format
  •   Allow connection between sites within hospital, region, and at
      a distance

i-Suites

Phone a Friend

Summary
 • Technology has allowed the development of
   laparoscopic surgery and imaging is likely the most
   important aspect of that development
 • Understanding the basic technology behind this tool
   allows a surgeon greater understanding of it’s uses and
   facilitates utilization of the advantages of the
   technology
 • It is important as a surgeon to understand the function
   of, and be able to troubleshoot all equipment that you
   use in the OR
 • Practice with the technology will increase your
   understanding