A Haptic-enhanced 3D real-time interactive needle insertion simulation for prostate brachytherapy

摘要

A virtual reality based surgical simulation can improve the accuracy and quality of prostate brachytherapy by facilitating surgeon training, rehearsal, and intra-operative assistance. In this paper, we describe a prototype 3D realtime interactive simulation environment for needle insertion and seed implantation for prostate brachytherapy. A restricted 3D ChainMail method, derived from the original 3D ChainMail method based on our modification, was used to account for dynamic soft tissue deformation during needle insertion. We improved the neighbor-searching algorithm for the original 3D ChainMail method to enable a complete search for any objects including strict-concave. A direct manipulation model for needle-tissue interaction was implemented. A haptic feedback has also been provided to enhance realism and training outcome. For simplicity and efficacy, we have adopted a distributed system structure functionally incorporating two software modules: visual simulation module and haptic simulation module. The simulation was demonstrated using four key steps of the brachytherapy procedure: 1) specification of seed positions inside the prostate; 2) placement of a needle at a specified entry point and trajectory; 3) insertion of the needle into the prostate consisting of two basic sub-steps: membrane contraction and penetration insertion; and, 4) retraction of the needle after seed implantation. The preliminary results of the simulation are promising.