Interaction modeling and simulation of a flexible needle insertion into soft tissues

Needle puncture is irreplaceable for some percutaneous therapies, like biopsy, brachytherapy treatment, neurosurgery, etc. But needle insertion force deforms soft tissue, making accurate targeting difficult. It thus emerges as an important issue to model the interaction force raised during needle insertion. In this paper, we establish the force model with data acquired from the simulation of a flexible needle insertion into a liver of human being. First, high-quality tetrahedral meshes of the flexible needle and the liver are generated using an adaptive constrained Delaunay tetrahedralization algorithm. Then, the tetrahedral mesh data is integrated into SOFA, an open-source framework, to dynamically simulate the interactive behaviours of the flexible needle insertion into the liver. Finally, interactive force data acquired from the simulations is identified and modelled in three parts, namely, stiffness, friction, and cutting forces. The models established may be used in robotic needle steering and insertion training with computer simulator.