6th Annual BMRP Investigator Meeting - Abstract

Fiber Optic Shape Tracking to Improve Inflammatory Bowel Disease Diagnosis

Caroline G.L. Cao^1,a, Lothar Lilge², Peter Wong¹, Hua Xing¹, Nate Zamarripa¹, Robb Gavalis<sup>1

1</sup>Department of Mechanical Engineering, Tufts University (Medford, Massachusetts, USA); ²Department of Medical Biophysics, University of Toronto (Ontario, Canada)

Colonoscopy is the current gold standard for inflammatory bowel disease diagnosis and colorectal cancer screening. Difficulties in performing colonoscopy, such as looping in the colon and disorientation, are due to the limited control of directing the flexible endoscope through the non-rigid colon and the near-blind navigation through the patient’s colon. A new shape tracking technology is being investigated to provide the operators with a real-time 3D image of the colonoscope on an augmented reality display. The key enabling technology for this navigational aid is a shape tracking sensor that utilizes a single optical fiber with differentiable fluorescent dyes or nanoparticles along the fiber. Laser-light illumination through the fiber results in varying degrees of fluorescence depending on the local curvature (i.e., more curvature results in more leakage and hence more fluorescence). A spectrometer collects the emitted spectra and further analysis allows for reconstruction of the 3D shape of the fiber-scope coupling, rendered in an augmented reality display. Initial research results include the successful modification of multi-mode fibers with silica-core/silica-cladding and dark buffer such that a small quantity of a fluorescent dye can be embedded in a 150 μm hole in the cladding. Emission spectra of the embedded dye in response to excitation light as a function fiber bend were obtained. Continuing investigation will focus on identification of more dyes or quantum dots with distinct emission spectra, and the construction of a multi-segment sensing fiber.