Finite element modelling of rolling indentation for tissue adomanlity identification

We describe a novel approach for demonstrate of a wheel-rolling tissue deformation as well as the abnormalities tissue depth evaluation using a rolling finite element model (RFEM). Since a wheeled probe which is capable of performing rolling tissue indentation has been proven to be a promising device to rapid conduct soft tissue property identification for localization and documentation of the abnormalities within the tissue, with the aim of compensating the loss of haptic and tactile feedback experienced during robotic-assisted minimally invasive surgery (MIS). To implement such a device requires a good understanding of the dynamics of the wheel-tissue rolling interaction and relationship between the tissue internal structure and the corresponding tissue reaction force. In this paper we propose the RFEM of the dynamic interaction between a wheeled probe and a soft tissue sample using ABAQUS finite element analysis software package. The aim of this work is to more precisely locate abnormalities depth within soft tissues using RFEM and aid surgeons better in the decision of resection during MIS through the understanding of dynamics of wheel-tissue rolling interaction. The soft tissue was modelled as a nonlinear hyperelastic material with geometrical nonlinearity and the modelling parameters were calibrated using experimental data from standard tests. The purposed RFEM consists of simulations of wheel-tissue rolling indentations on a silicone phantom with varied tissue internal structure and also running on a biological tissue such as a porcine kidney. The results show that the proposed method can predicted the wheel-tissue interaction force of the rolling indentation with a good agreement results and the documentary from empirical equation of RFEM can identify the simulated tumors depth accurately.