Multifiber optical bend sensor to aid colonoscope navigation

Abstract

A colonoscopy's near-blind navigation process frequently causes disorientation for the scope operator, leading to harm for the patient. Navigation can be improved if real-time colonoscope shape, location, and orientation information is provided by a shape-tracking aid, such as a fiber optic bend sensor. Fiber optic bend sensors provide advantages over conventional electromechanical shape-trackers, including low cost and ease of integration. However, current fiber optic bend sensors lack either the ability to detect both bending direction and curvature, or the ability to detect multiple localized bends. An inexpensive multifiber bend sensor was developed to aid users in navigation during colonoscopy. The bend sensor employs active-cladding optical fibers modified with fluorescent quantum dots, bandpass filters, and a complementary metal-oxidesemiconductor imager as key components. Results from three-fiber sensors demonstrate the bend sensor's ability to measure curvature (error of 0.01 mm), direction (100% accuracy), and location (predetermined distance) of a bend in the fiber bundle. Comparison with spectroscopy data further confirmed the accuracy of the bending direction measurement for a three-fiber sensor. Future work includes improvements in fiber manufacturing to increase sensor sensitivity and consistency. An expanded 31 fiber bundle would be needed to track the full length of a colonoscope. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Detecting the Formation of a Loop in Endoscopic Tubing Using Fiber Optic Techniques

“…These optical fibers was embedded into the endoscope as part of a detection circuit so that would not subject to any outside interference and will add no additional bulk or stiffness to the existing endoscope. In normal operation, light from one end of the fiber is received at the other end; however, when the cable forms a loop, losses in light intensity will occur when the bend radius of the fiber exceeds the critical angle necessary to confine the light to the core area and there is a leak into the cladding [1,4,5].…”