Integrated Fluorescent Probe & Radiofrequency Ablator Rachel Riti & Alex Walsh Advisors: Bart Masters & Anita Mahadevan-Jansen

Outline Background – RFA, Fluorescence Motivation Objective Performance Criteria Proposed Designs Future Work

Radiofrequency Ablation Ablation of tissue using high frequency radio waves Applied in lung, kidney, breast, bone and liver tumors Explain the protocol for RFA

Fluorescence Emission of light by a substance that has absorbed light of a different wavelength Property of biological tissue Collagen, NADH, Elastin

Motivation Determination of ablated area Current Method Thermocouples Alternative Methods Tissue Markers, Thermal Camera Proposed Method Fluorescence

Temperature Dependence of Fluorescence Walsh A, Masters DB, Jansen ED, Welch AJ, Mahadevan-Jansen A, The Effect of Temperature on Fluorescence: An Animal Study, Lasers in Surgery and Medicine. Publishing Pending

Objective Design a probe capable of both fluorescence and measurements of RFA Build the designed probe Test the probe

Size Constraints

Performance Criteria Maintain RFA efficiency Determine region of ablation Accuracy Within 10% of original fluorescence intensity Determine margins of ablation within 5% Brainstorming Ideas

Prototype 1 15 cm RFA Probe 19 cm Fiber optic 1 collection fiber, 1 excitation fiber Laser

Validation RFA functionality not compromised Fiber functional during RFA Probe entry not affected Observable significant difference between ablated and normal tissue Measurement of ablation area

Fiber Geometry Collection Fibers Excitation Fibers

Fiber Dimensions

Prototype 2 Fiber enclosed 2-5 cm 15 cm 2 excitation fibers, Increase the gauge of the trocar shaft 2 excitation fibers, 2 collection fibers

Validation RFA functionality not compromised Fiber functional during RFA Probe entry not affected Adjustable fiber length during procedure Fluorescence measurements accurately indicate ablation area

Timeline Timeline Process Description November Research Attempt to answer the following questions: What is an RFA? How is temperature measured during RF ablation? How can fluorescence be used to measure temperature? December Develop Preliminary Design Determine the best way to build a combined RFA and fiber optic so that both instruments are fully functional when integrated. January Reevaluate Design Review the previous design with supervision of mentors and make necessary changes. Build Fiber Follow the necessary steps to create multiple fibers for collection. February Integrate RF Ablator and Fiber Build the fibers into the prongs of the RFA. Test Test the functionality of the RFA and the fibers as an integrated unit using bovine livers. March Design Critique Determine the functionality of the integrated unit and possible areas of redesign. Possible Further Research Expand research to include mechanical aspects of RFAs and fiber optics, as well as safer design techniques. Begin Redesign Begin constructing a revised design for the probe. April Complete Redesign Complete revised design with supervision of mentors and make necessary changes. Test the functionality of the redesigned probe on bovine livers.