Multifiber optical bend sensor to aid colonoscope navigation

Jessica E. Kesner, Robb M. Gavalis, Peter Y. Wong, Caroline G.L. Cao

Research output: Contribution to journalArticlepeer-review


A colonoscopys 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-oxide-semiconductor imager as key components. Results from three-fiber sensors demonstrate the bend sensors 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.

Original languageEnglish (US)
Article number124402
JournalOptical Engineering
Issue number12
StatePublished - Dec 2011
Externally publishedYes


  • active-cladding
  • bend sensor
  • fiber optics
  • fluorosensor
  • navigation
  • quantum dots

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Engineering


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