Parameter Measurement Of Human Soft Tissue And Its Application In Virtual Surgery System

Recent years, virtual surgery is one of the most important research areas in virtual reality. It could be used in training new doctors as well as planning for real surgery. The basic of implementing a virtual surgery system is modeling of human organs. There are kinds of ways in such modeling and one of them is so called FEM (Finite Element Method). FEM simulates an object with its material characteristics. So if parameters related to object material characteristics could be gained, a model would deform as a real one, which, is the first requirement in implementing a virtual surgery system. This paper focuses on the parameter measurement of human soft tissue and its application in virtual surgery system.In this paper, the theory of FEM is first introduced. The statics as well as dynamics functions are deduced. During the procedure, stress-strain relationship and the average density are figured as the most important parameters in FEM. The theory of clinical trail is also introduced in this paper. The parameters of modeling liver and kidney are measured by vivo experiment. Both qualitative and quantitative experiments are used to validate the modeling results. After using the experimental parameters in liver model, the result of deformation is increased by 6.6% compares to model uses experience parameters, and 0.3% compares to model uses parameters gained from traditional experiment. There are no traditional parameters in kidney modeling, so we only compare the experience parameters and the experimental parameters introduced in this paper. The deformation of kidney is also improved and the increased ratio is 9.5%. The main works and innovation points are as described as follows:1. Stress-strain relationship and average density of material are figured as the most important parameters in FEM modeling.2. A bridge to connect energy function related to material characteristics and stress-strain relationship is built. After detailed comparison and analysis, a combined exponential and polynomial strain energy function is chosen to simulate a soft tissue with FEM.3. Soft tissues are simulated with the experimental parameters which could improve the effect of modeling and accelerate the process of FEM because of preventing waste of time on finding appropriate parameters.4. Liver experimental parameters are compared with traditional parameters. Kidney parameters are gathered which haven't been gathered before. It supplies more reference data in soft tissue modeling.5. An experiment framework is introduced which could be used to gather and validate parameters of modeling other organs in a virtual surgery system.6. The experimental parameters are put into virtual surgery system. It has a great clinical value.