| Colonoscopy is the current gold standard for colon cancer screening and diagnosis. However, the near-blind navigation process employed during colonoscopy results in endoscopist disorientation and scope looping, leading to missed detection of tumors, incorrect localization, and pain for the patient. A fiber optic bend sensor, which fits into the working channel of a colonoscope, was developed to aid navigation during colonoscopy. A bundle of three optical fibers whose cladding was modified with quantum dots (QDs) comprise the bend sensor. During bending, light lost from the fiber's core is coupled into modified QD zones, inducing fluorescence intensity proportional to the degree of bending and a color characteristic of bending direction. A LabVIEW program converts fluorescence information detected by a monochrome complementary metal oxide semiconductor camera into a graphical shape representation. The sensor and the graphical display were evaluated in a preliminary evaluation study. Ten subjects participated in a 2-display x 2-order x 9-colon shape mixed design experiment, using a colonoscope with a sensor prototype to perform a simulated colonoscopy task. Results demonstrate the sensor's ability to track bending direction, curvature, and location of the colonoscope in various colon shapes, but with a 66% error rate. Future work includes improving sensor accuracy and dynamic response, and expanding the length of the sensor to 1.8 meters. |
