In-Vivo Pan/Tilt Endoscope with Integrated Light Source

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In-Vivo Pan/Tilt Endoscope with Integrated Light
Source

• Tie Hu, Ph. D, Peter K. Allen, Ph. D, Dennis L.
  Fowler, M.D.
• Department of Computer Science
• Department of Surgery
• Columbia University, New York

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Outline

• Motivation
• Introduction
• Proposed Solution
• Prototype Device I and II
• Animal Tests
• Results and Conclusion
• Contributions and Future Work
• Acknowledgement

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Minimally Invasive Surgery
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Limitations of Standard Endoscope

• Paradigm of pushing long sticks into small
  openings.
• Narrow angle imaging.
• Limited workspace.
• Counter intuitive motion.
• Assistants needed to control the camera.
• Additional incisions for other laparoscopic
  instruments.

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Robotic Surgery

• Robotic surgery is future of surgery.
• Increase the dexterity and fine motion
  capabilities of surgeon.
• Decrease the tremor of surgeons hand.
• Enable remote operation.
• Current surgical robot.
• Enormous size.
• Extremely high cost.
• Multiple assistants needed.
• Multiple incisions needed as non-robotic MIS.
• Compact and inexpensive surgical robot is needed.

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In-Vivo Imaging Devices

• Rod-lens by Hopkins and cold light source of
  fiber optics by Karl Storz.
• Flexible endoscope using fiber optics to delivery
  light and transmit image.
• Pill camera without locomotion.
• Endoscope with rotating mirror.
• Endoscope positioned by multilink arm with
  piezoelectric actuators.

Karl Storz Endoscope
Flexible Endoscope
Pill camera
Gao et al., 1998
Ikuta et. al., 2002
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Proposed Solution

• An insertable surgical robot platform with
  sensors and effectors in the body cavity where
  they can perform surgical imaging tasks
  unfettered by traditional endoscopic instrument
  design.
• A prototype of a novel insertable Pan/Tilt
  endoscope with integrated light source.
• The incision port is left open access, allowing
  for single port surgery.

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Prototype Device I

• Stereo camera with 6 DOF are desirable full
  mobility
• Difficult to achieve in small actuated package
• Compromise 3 DOF per camera
• Cameras share tilt axis (1 DOF)
• Independent translation (2 DOF)
• Independent pan (2 DOF)

Design of 5-DOF insertable camera device
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Single Camera Prototype I
Diameter 22 mm Length 190 mm Camera opening
58 mm 3 DOF Pan 120 Tilt 130 Translation
50 mm
Video
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Improvements Needed for Prototype II

• Much reduced size
• Smaller diameter
• Reduce length
• Needs light source
• Make imaging head modular design
• Tradeoff Degrees-of-freedom for compactness

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Prototype II

• 110 mm in length and 11 mm in diameter.
• 120 degrees Pan/ 90 degrees Tilt.
• Integrated 8 LED light source and miniature
  camera module.
• Package to protect the delicate electronics and
  fragile wires from body fluid and moisture.
• Fully sealed camera module.
• Joint sealed by rubber boot.
• Joystick control.

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Prototype II (Cont.)
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LED Light Source

• Light-emitting diode (LED) as a light source in
  laparoscopy
• Lower power
• Higher efficiency
• Compact package
• Longer lifespan
• Lower cost
• Luxeon portable PWT white LED(LXCL_PWT1)
• 2.0 X1.6 X 0.7 mm
• 26 lumens of light at 350 mA
• 8 PWT LED in a printed circuit board with 9mm
  diameter.
• 208 lumens light at 8.4 w

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Camera Module

• Pin hole lens (PTS 5.0 from Universe Kogaku
  America)
• Focal length 5.0 mm.
• F number 4.
• Angle of view D-H-V(85.4-68.3-50.9 ).
• 6.5 mm CCD camera sensor.
• NET USA Inc, CSH-1.4-V4-END-R1.
• 450 TV lines in horizontal resolution and 420 TV
  lines in vertical resolution.
• Protective window by sapphire.

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Pan/Tilt Mechanism

• Miniature Brushless DC motor (0513G, Faulhaber
  Group).
• 25mNm output torque.
• 5.8 mm in diameter.
• Miniature worm gear (Kleiss Gear Inc.)
• Gear ratio 161.
• Compact size.
• Increased torque.
• Sleeve bearing to reduce the friction of tilt
  motion.

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Working Device in the Animal Test
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Laparoscopic Procedures
Video
Appendectomy
Running (measuring) the bowel
Suturing
Nephrectomy
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Timing of Each Procedures for Laparoscope and our
device
Procedure Laparoscope (minutes) Robot (minutes)
Running Bowel 420 330
Appendectomy 220 220
Suturing 500 400
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Conclusion

• Easier and more intuitive to use than a standard
  laparoscope.
• Joystick operation requires no specialized
  operator training.
• Field of view and access to relevant regions of
  the body were superior to a standard laparoscope
  using a single port.
• Time to perform procedures was better or
  equivalent to a standard laparoscope.

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Contributions and Future Work

• Contributions
• Built an insertable camera with Pan/Tilt and
  integrated LED light source.
• Accomplished a series of standard laparoscopic
  procedures( appendectomy, running (measuring) the
  bowel, suturing, and nephrectomy) by laparoscopic
  surgeon using the device.
• Future Work
• Camera with zoom and auto-focusing capabilities.
• Stereo camera in one package.
• Function with tool or organ tracking.

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Acknowledgement

• We thank Nancy Hogle for her help in project
  development and lab support.
• This work was supported by NIH grant
• 1R21EB004999-01A1.