Analysis of Dynamic Tissue Deformation during Needle Insertion into Soft Tissue

Tissue deformation is one of the most significant factors, which effects the needle placement inside the soft tissue. Based on the analysis, a tissue deformation model is presented to quantify the volume of tissue deformation. The geometry of tissue deformation is analyzed, and the cone is used to approximate the shape of tissue deformation. The methods for measuring the depth and radius of tissue deformation are introduced to calculate the volume of tissue deformation. The dynamic needle-tissue interactions are investigated, and the potential, kinetic, dissipated, viscous and strain energies are analyzed based on the energy conservation law. The needle insertion experimental setup, consisting of a linear actuator, a force sensor, a needle, a tissue container and a light, is constructed to obtain the test data. The experiments are performed on the artificial tissue specimens, and the energy-based fitting model for the tissue deformation is presented to estimate the the volume of deformation. The results show that the model could predict the volume of tissue deformation and determine the zone of tissue deformation.