An optical tactile array probe head for tissue palpation during minimally invasive surgery

This paper presents a novel tactile probe head designed for tissue palpation during minimally invasive surgery (MIS). The probe head uses fiber optics and consists of 14 tactile sensing elements at 2.5-mm spacing with a diameter of 14 mm. Each tactile element contains a microstructure converting the tissue reaction force applied on sensing nodes into a circular image pattern through transmitting and receiving fibers. The image patterns of all the sensing elements are captured by a camera attached at the proximal end of the receiving fibers and are converted to tactile force feedback through image processing. Validation tests showed that each sensing element of the tactile probe head can measure forces from 0 to 0.5 N with a resolution of 0.05 N. The proposed sensing probe is low cost, lightweight, sterilizable, easy to be miniaturized, and magnetic resonance environment compatible. Experiments were performed for testing the probe's capability of detecting the tissue abnormality through spatial distribution of tactile force feedback. The proposed tactile probe head with its capacity to accurately detect nodules embedded inside soft tissue can be an effective tool in surgical palpation during MIS.