The Design of Optical Sensing Needles for Tactile Sensing and Tissue Identification at Needle Tip

Abstract

Force sensing in minimally invasive surgery is a challenge for surgeons in practice and in training, and for the application of invasive devices. Within magnetic resonance (MR) working environments the solutions are limited. Optical sensors are a promising choice as they are immune to MR influence. This paper proposes optical sensing solutions for needle-tip applications of needle-tip tactile sensing and bio-tissue identification, based on interference intensity modulated Fabry-Perot interference (FPI) principle. The design of the sensor and its optical circuit are detailed described. Then, simulations, phantom tests, ex-vivo and in-vivo animal tests have been conducted to verify the design. During the experiments, sensor properties and environmental influence factors on the sensor were investigated. The results show that the designed needles are capable of identifying tissue layers and types via analyzing force signals during the insertion process in real time mode in a temperature-changeable environment, with effective temperature compensation designs.