Virtual Simulation And Training Of Laparoscopic Cholecystectom

With the development of simulation technology,virtual surgery simulation system has been widely used in the medical field.Virtual surgery simulation system mainly uses computer technology to reconstruct three-dimensional virtual surgery environment,reconstruct organ models based on medical anatomical data and image data,and use interactive devices to simulate operations on three-dimensional organ models.Laparoscopic virtual surgery simulation with visual and haptic feedback provides great help to doctors in surgical teaching,surgical rehearsal,and postoperative evaluation,which can effectively improve surgical efficiency and quality and reduce surgical risks.In response to the requirements of laparoscopic cholecystectomy for realistic and real-time surgical simulation,we analyze the following three aspects: 1)Realistic virtual surgery simulation scenarios and physical modeling of soft tissue models.2)Reasonable and efficient cutting deformation simulation framework.The specific research work in this dissertation is divided into two specific aspects as follows:Build simulation scenarios based on medical anatomy data.In this dissertation,the structure of the gallbladder is analyzed according to medical anatomical data,and the gallbladder model obtained with 3D reconstruction technology is modified according to the anatomical diagram of the human gallbladder as well.According to the realism of the simulation scene and the requirements of the used cutting algorithm,the gallbladder simulation scene is modeled in groups,and the simulation model is assembled and the parameters are set in the body model generator.The biomechanical properties of the gallbladder and other soft tissues and the connection between the gallbladder and other soft tissues were also analyzed and determined in order to achieve realism in the simulation.The deformation and cutting based on linked voxels and adaptive octree mesh.In this dissertation,to resolve the conflict between simulation computation and simulation speed,a GPU-CPU parallel framework is used for virtual simulation.In the cutting simulation,this paper proposes corresponding cutting algorithms according to different internal structures.According to the difference of cutting position structure,three cutting methods are proposed,namely,no internal structure,embedded surface structure and embedded material sub-region.When simulating the deformation of the flexible body model,the collision force acting on the voxel is transformed into the collision force acting on the vertices of the octree cube and the co-rotating linear finite element method is used to make the flexible body model produce reasonable deformation,and the deformation state of the face mesh vertices is calculated according to the deformation gradient.