Image Guided Robotic Biopsy

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Image Guided Robotic Biopsy

• Group Members
• Ryan Augustine
• Nate Gaeckle
• Brian Frederick
• Gordy Lawrence
• Advisor Professor Willis Tompkins
• Client Dr. Myron Pozniak

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Abstract

• A robotic arm has been developed to eliminate the
  humans errors of biopsies
• The Robotic Arm advances the needle slowly
• Causes tumor movement and inaccurate biopsies
• Increases risk of internal injury
• We designed a pneumatic driver that should
  quickly insert and remove the needle
• Three prototypes have been assembled
• Needle retrieval and sampling designs have yet to
  be built

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Motivation

• Problems with current drive mechanism
• Slow needle advancement 2 cm/s
• Slower biopsies increases risk of internal damage
• Creates tumor movement
• Makes use of the robotic arm infeasible

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ImageGuide, 2004
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Problem Definition

• Biopsies are used in conjunction with a CT scan
• Many dilemmas with manual biopsy needle injection
• Inaccurate
• Physician exposure to radiation
• Sometimes multiple attempts at tumor capture
• Robotic Arm created to eliminate these problems

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Problem Statement

• Our goal is to create a needle driver that
• Drives a needle fast to counter tumor movement
  and patient injury
• Retracts the needle with speed and ease with a
  sample of the tumor
• Is compatible with CT scanners
• Preserves Imageguide Inc.s Remote Center of
  Motion for the Robotic Arm

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Design Criteria

• Device must not be any longer than 30 cm
• Radiolucent material
• Must have redundant safety checks
• Needle must be extracted rapidly with tissue
  sample
• Needle must be fired fast enough to utilize
  inertia of body tissue
• Biopsy should be completely automatic

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Current Design

• Needle contained inside piston/cylinder assembly
• Needle injected and retracted via pneumatic power
• Meets length restrictions
• Most parts may be constructed from plastic

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• Internal view of final pneumatic firing system
• Needle inside cylinder
• Needle able to inject or retract based on
  direction of air flow

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Testing with Metallica

• Tested needle deflection through the soft portion
  of a pigs foot and gelatin
• Needle velocity estimated at 4 m/s at 5psi
• 2000-4000 lbs/in2 generated at needle tip
• Needle bent on first trial into pigs foot

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Silver Bullet vs. The Turkey Breast

• Shot through easily with no apparent deflection
  at various heights
• Shot at 30 psi
• More pressure was needed for the prototype to be
  successful

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Silver Bullet vs. The Pig

• Qualitative assessment for a proper distance from
  patient
• Enhanced performance as pressure increased
• 50 psi worked the best
• Compromises material selection
• Tested on wide range of tissues
• No variability in needle behavior

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Retraction Mechanism

• Solenoid valve alternates air flow to retract
  needle
• Compressed air
• Vacuum line
• Retroreflector sensor
• senses when needle is at the end of the tube
• causes the solenoid valve to switch to vacuum
  line

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Needle Designs
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Future Work

• Design mechanism within plunger to cause biopsy
  needle to capture tissue
• Implement valve to direct air flow
• Design mechanism to sequence firing and
  retracting
• Implement radiolucent material
• Interface with ImageGuide robotic arm
• Needles of different length

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References

• ImageGuide, Inc. Feb. 16, 2004. Image-Guided
  Robotics for Minimally Invasive Cancer Diagnosis
  and Therapy. PowerPoint Presentation.
• Chesler, N. 2004. Personal Interview
• Fronczak, F. 2004. Personal Interview
• Pozniak, M. 2004. Personal Interview
• Sidney, D. 2004. Personal Interview
• Webster, J. 2004. Personal Interview

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