UC Berkeley

We present algorithms for simulating and visualizing the insertion and steering of needles through

deformable tissues for surgical training and planning. Needle insertion is an essential component of

many clinical procedures such as biopsies, injections, neurosurgery, and brachytherapy cancer treatment.

The success of these procedures depends on accurate guidance of the needle tip to a clinical

target while avoiding vital tissues. Needle insertion deforms body tissues, making accurate placement

difficult. Our interactive needle insertion simulator models the coupling between a flexible

needle and deformable tissue. We introduce (1) a novel algorithm for local remeshing that quickly

enforces the conformity of a tetrahedral mesh to a curvilinear needle path, enabling accurate computation

of contact forces, (2) an efficient method for coupling a 3D finite element simulation with a

1D inextensible rod with stick-slip friction, and (3) optimizations that reduce the computation time

for physically based simulations. We can realistically and interactively simulate needle insertion

into a prostate mesh of 13,375 tetrahedra and 2,763 vertices at a 25 Hz frame rate on an 8-core 3.0

GHz Intel Xeon PC. The simulation models prostate brachytherapy with needles of varying stiffness,

steering needles around obstacles, and supports motion planning for robotic needle insertion.

We evaluate the accuracy of the simulation by comparing against real-world experiments in which

flexible, steerable needles were inserted into gel tissue phantoms.