Development of deformable organ model for the realistic virtual surgery simulation system

摘要

We have been developing a virtual surgery simulation system that uses virtual reality techniques. In order to perform real-time simulation, we have to develop a deformable organ model without using the finite element method. Moreover, the organ model was designed to respond to any force applied to it that may occur during an actual surgical operation. To achieve these, we made a method to create an elastic organ model by the name of sphere filled model in our previous research and development. Because of the expression only by the internal spheres' behavior, this model is suited for a real-time simulation and quantitative deformation. However, the model in initial stage becomes problematic in case of complicated incisions. Therefore, we modified this model by developing an algorithm for organ deformation that permits various, complicated incisions including the effect of gravity. In addition, various physical manipulations that involve pressing, pinching, and incising an organ's surface could be performed. Then, we enabled the deformation of the internal structures only by using the internal sphere's behavior, in particular the deformation to blood vessel structures in the organ. This organ model provided the system with a more realistic simulation of various organ manipulations in virtual space.