Fiber Optic Force Sensor for Medical Applications within a Backbone-shape Structure

Abstract In recent years, the needs of force measurement in medicine are becoming stronger to realize further effective treatments and quantitative assessments. For example, quantitative safety assessment can be realized by introducing such force sensors by monitoring the interaction force on the conventional medical devices - such as surgical knife or forceps, to the organs. In addition, as force information is significantly deteriorated in the domain of Minimally Invasive Surgery (MIS) due to the discrepancy of eye- hand coordination and frictions of MIS devices through the body incision holes, the surgeons must perform the surgery in obtaining the force information alternatively from the vision through endoscope. Therefore, such force sensors potentially play a key role for the surgery with further quantitative assessments. From these backgrounds, we propose a new force sensor using fiber optic that is compatible with medical applications. Fiber Bragg Grating (FBG) enables force measurement in the long axis of the fiber by measuring the wavelength shift of spectral response of light source. In contrast with conventional force measurement methods such as strain gauge, FBG sensor does not emit any electric noise, either be influenced. The presented backbone shape allay force sensor using FBG fiber optic was developed to realize a bending force sensing in a compact stick shape implementation with the capability of sterilization, temperature compensation and output amplification. In this paper, the sensor structure, mechanical principle, prototype implementation and evaluations are descried.