OCT Penlight Sara Hanrahan Brock Nichol Gina Rodriguez Areej Sajjad University of Pittsburgh Senior...
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Transcript of OCT Penlight Sara Hanrahan Brock Nichol Gina Rodriguez Areej Sajjad University of Pittsburgh Senior...
OCT Penlight
Sara Hanrahan
Brock Nichol
Gina Rodriguez
Areej Sajjad
University of PittsburghSenior Design - BioE1161
Outline• Background
• Objectives
• Product design specifications
• OCT Penlight design
• Results
• Budget
• Validation & verification
• Future work
What is Glaucoma?
• Damage to the optic nerve that may lead to vision loss or complete blindness
• 66.8 million people with visual impairment• 6.7 million suffering from blindness [1]
[1] http://www.ahaf.org/glaucoma/about/glabout.htm - Accessed December 4, 2007
Possible Cause of Glaucoma
• Schlemm’s canal clogged, preventing aqueous humor from escaping
• High intraocular pressure (IOP)
Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainsville, Florida: Triad Publishing Company, 1990.
Canaloplasty: A Promising Solution
• Expand Schlemm’s canal to relieve IOP
• New, safe, and minimally invasive technique (do not have to enter anterior chamber)
• Biggest challenge: surgeon has to find Schlemm’s canal
Market Size
• In 1999, 400,320 glaucoma surgeries were conducted in the US [2]
• These patients could benefit from the OCT Penlight
• There are approximately 7,500 hospitals in the US [3]
[2] Strutten, Walt, J Glaucoma. 2004 Jun;13(3):221-6.[3]http://www.census.gov/PressRelease/www/releases/archives/
facts_for_features_special_editions/004491.html
Optical Coherence Tomography (OCT)
• Acquires a cross-sectional image of the eye
• Penetrates about 2 mm into tissue
• High resolution imaging technology
• Currently used for diagnostic purposes
OCT Handheld
Real-Time Tomographic Reflection (RTTR)
Stetten, G., Chib, V., Hildebrand, D., Bursee, J. “Real Time Tomographic Reflection: Phantoms for Calibration and Biopsy.” IEEE/ACM International Symposiium on Augmented Reality. 2001 Oct:11-19. New York City.
Objectives
• Long term goal:• Locate Schlemm’s canal with more ease
during surgery
• Short term goal:• Place a 30 gauge needle into a goat eye
guided by the OCT penlight
OCT Penlight Components
MechanicalComponent
Calibration Arm
Product Design Specifications
• Place virtual image accurately (100 µm tolerance)
• Allow a sufficient working area
• Weigh less than 2 lbs
• Clamp onto a 3 cm diameter lens
• Software and hardware capable of acquiring image from OCT device
Mechanical Design
• Virtual image plane must be placed along OCT scanning beam
• Must be structurally stable
• Must be fixed display
virtual image
mirror
Electronic System
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Handheld OCT
VGA Signal Splitter
Signal Analysis
Computer
OCT Software Display
OCT Penlight Computer
OCT Penlight Display
Patient
VGA Capture Device
Software
Capture Screen
Crop Display
Display our software using OpenGL + GLUT
Scale X
Scale Y
Rotate
Translate
Calibration• Purpose
• Guide user in positioning the virtual image to its accurate location on the scanning plane
• Process
• 3 pins within scanning range
• Pins scanned and image displayed
• User aligns virtual image
• Easily detached
4.5 mm
2 mm
Prototype Fabrication
• Stereolithography (SLA)
• Lightweight
• Cost-efficient
• Sufficiently sturdy
• Readily available
Final Product
A: Flexible armB: OCT Handheld DeviceC: Lens of OCTD: OLED DisplayE: Half-Silvered MirrorF: Calibration Arm
Calibration Set Up
Calibration Process
Displaying the Virtual Image
mirror
Testing the OCT Penlight
QuickTime™ and aMPEG-4 Video decompressor
are needed to see this picture.
QuickTime™ and aMPEG-4 Video decompressor
are needed to see this picture.
Validation & Verification
• Allow a sufficient working area• Approved by an experienced ophthalmologist
• Weigh less than 2 lbs• Using a scale, we weighed entire device
• Clamp onto a 3 cm diameter lens• OCT Penlight was able to clamp onto lens and
maintain position for at least two hours
Validation & Verification• Software and hardware capable of acquiring
image from OCT device• Run the software and see if image on monitor is
visible on the Penlight display
• Placement of virtual image must be accurate (100 µm tolerance)• Examine calibration process through a
microscope
• Objective must be met• Guide user in penetrating a goat eye with a 30
gauge needle using OCT Penlight
Future Work
• Use a higher quality microscope to obtain clearer pictures of the virtual image
• Attach OCT Penlight directly to surgical microscope
• Automate calibration
• Test Penlight on live specimens
• Make software faster• More efficient video capture
BudgetItem Approximate
CostAdditional Notes
Mirror $10 Already availableOLED Display $800
Rapid Prototyping
$300 Stereolithography
VGA Splitter $100VGA to USB
Video Capture Device
$300
Cow Eyes $2.50 eachFlexible Arm $38OCT Scanner $85,000 Normally available in most
hospitals and does not require purchasing
Project Management
1-Jan 11-Jan 21-Jan 1-Feb 11-Feb 21-Feb 1-Mar 11-Mar 21-Mar 1-Apr 11-AprInitial ResearchMechanical DesignPenlight PrototypingElectronics and Software DesignCalibration DesignCalibration Arm PrototypingInitial TestingDesign ExperimentLab Testing
Acknowledgements
• Sources of funding• Generous gift of Drs. Hal Wrigley and Linda Baker
• Department of Bioengineering
• Mentors• Dr. George Stetten
• Larry Kagemann
• Additional help• Andy Holmes
• Gaurav Shukla
• Dr. John Galeotti
• Dr. Bing Wu
• Dr. Gadi Wollstein
Questions