Simulation of Coupling Process of Flexible Needle Insertion into Soft Tissue Based on ABAQUS

In order to get to the desired target inside the body,it is essential to investigate the needle-tissue coupling process and calculate the tissue deformation.A cantilever beam model is presented to predicting the deflection and bending angle of flexible needle by analyzing the distribution of the force on needle shaft during the procedure of needle insertion into soft tissue.Furthermore,a finite element(FE)coupling model is proposed to simulate the needle-tissue interactive process.The plane and spatial models are created to relate the needle and tissue nodes.Combined with the cantilever beam model and the finite element needle-tissue coupling model,the simulation of needle-tissue interaction was carried out by the ABAQUS software.The comparing experiments are designed to understand the needle-tissue interactions,by which the same points in the experiments and simulation are compared and analyzed.The results show that the displacements in x and z directions in the simulation can accord with the experiments,and the deformation inside the tissue mainly occurs in the axial direction.The study is beneficial to the robot-assisted and virtual needle insertion procedure,and to help the physicians to predict the inside tissue deformation during the treatments.

Soft Tissue Deformation Modeling in the Procedure of Needle Insertion:A Kriging‑Based Method

The simulation and planning system(SPS)requires accurate and real-time feedback regarding the deformation of soft tissues during the needle insertion procedure.Traditional mechanical-based models such as the finite element method(FEM)are widely used to compute the deformations of soft tissue.However,it is difficult for the FEM or other methods to find a balance between an acceptable image fidelity and real-time deformation feedback due to their complex material properties,geometries and interaction mechanisms.In this paper,a Kriging-based method is applied to model the soft tissue deformation to strike a balance between the accuracy and efficiency of deformation feedback.Four combinations of regression and correlation functions are compared regarding their ability to predict the maximum deformations of ten characteristic markers at a fixed insertion depth.The results suggest that a first order regression function with Gaussian correlation functions can best fit the results of the ground truth.The functional response of the Kriging-based method is utilized to model the dynamic deformations of markers at a series of needle insertion depths.The feasibility of the method is verified by investigating the adaptation to step variations.Compared with the ground truth of the finite element(FE)results,the maximum residual is less than 0.92 mm in the Y direction and 0.31 mm in the X direction.The results suggest that the Kriging metamodel provides real-time deformation feedback for a target and an obstacle to a SPS.