1. Real-time Parathyroid Visualization System for use in Endocrine Surgery Oral Presentation 4 March 18, 2010 BME 273 Senior Design Group 1 Isaac Pence Advisors: Dean Paras Dr. Mahadevan-Jansen

2. 37,000 new cases of Thyroid cancer in U.S. every year: >99% treated by parathyroidectomy 100,000 new cases of Hyperparathyroidism in U.S. every year: 95.5% one enlarged gland <1% cancer of parathyroid -Osteoporosis, gastric ulcers, pancreatitis, kidney stones and bone fractures Just the basic facts…

3. Significance Parathyroid operation typically takes 2 to 6 hours to complete (depending on case and skill of surgeon) 5-15% of patients not cured after the operation. –Increased cost and pain from recurrence, persistence of disease or surgical error Expected hospital stay of 1 to 3 nights $10,288 for in-patient stay– entire system should total less than cost of single repeat case with in-patient stay

4. Inadvertent removal of parathyroid glands during endocrine surgery Iatrogenic injury common after procedures Resultant hypoparathyroidism and hypocalcemia can cause major health concerns Success primarily dependent upon surgeon experience No methods for visual distinction between similar tissues Problem:

5. Optics lab have determined higher parathyroid autofluorescence compared to other neck tissues Previous work undertaken to develop system for visualization system Design Criteria: System must be easy to use, requiring little to no training Function in real-time, with intuitive information output Easily integrated into surgical setting Reduce time and error-rates of current surgical practices Develop a real-time visualization system:

6. Objective: Idea: Employ relative thyroid and parathyroid auto-fluorescence to develop a real-time imaging system for use in endocrine surgery Find-R-Scope from previous Senior design project Drawbacks: Poor Image quality (low quality lenses) Surgical Considerations Unwieldy Configuration Limited penetration depth

7. Solution: IR Viewer Modification Method: - Diode laser (785nm) to emit excitation wavelength - Improve existing detector interface: - Alter handle configuration to allow reliable support (better integrate in surgical setting) - Add adapter to interface C-mount lenses - Determine optimal coupling of image into CCD - Write LabView VI to compile information - Employ false color for simple user interface - Test with sample tissue and in surgery

8. Considerations Imaging system must be able to clearly focus on entire surgical cut, approximately 6 inch diameter Sterile field surrounds patient: ~3 feet Surgeon needs visual indicator of parathyroid margin (focus <1 inch) within context of surgical field Imaging to be done no closer than 1 foot from patient Initial considerations are subject to change, input obtained from Dr. Phay and Dr. Broome of VUMC Endocrine surgery

9. Preliminary Results By removing front end of casing, further testing of lenses can be conducted

10. Preliminary Results At 3 feet from target, Navitar lens couple straight into imaging tube. Far (left) and near (right) focus images

11. Preliminary Results

12. Images with new front end from 3 feet both near (left) and far field (right). Spherical aberrations still present, allows incorporation of filter.

13. Goals: - Determine if fixed zoom lens will provide higher resolution Compare F-mount camera lenses with current C-mount zoom - Determine necessary excitation parameters - Improve necessary program interface - Find appropriate fluorescence standard for threshold creation - Verify system in vitro

14. Performance Indicators: Percentage of accurate identifications made when compared to histology and surgeon determination Time required for surgical procedure Cost of implementing system

15. Continuing Work: Characterize lens interface with viewer Compare F-mount fixed zoom lenses with current setup Upcoming: Developing software for fluorescence quantification, incorporate aberration correcting software Determine optimal filter configuration for desired image, characterize Razoredge filter for fluorescence reduction Order a suitable filter, potentially a Razoredge by Semrock© Incorporate NIR illumination for visual registration during surgery Determine Fluorescence standards or phantom creation