Study On Key Technologies Of Endovascular Surgery Training Simulation And System Construction

Vascular interventional surgery is currently one of the most effective methods for treating severe cardiovascular and cerebrovascular diseases,in which the metal guide wire will be pushed into the lesion area to achieve effective treatment.However,vascular interventional surgery is difficult to operate and X-rays emitted from intraoperative imaging equipment are harmful to human body.To improve the doctor’s skills of vascular intervention and induce X-ray injuries,a virtual training system of vascular interventional surgery is designed.In this paper,the key techniques of the virtual training system,involving modeling of blood vessels and guide wires,collision detection and force feedback calculations are discussed.The specific work of this thesis is as follows:(1)The visual modeling and physical modeling of blood vessels and guide wires in virtual surgical scenes are studied.For the smooth,elastic and incompressible physical properties of vascular,the physics model and flexible deformation calculation method based on the tensor finite element method are proposed.It performs well in the simulation as well as the real-time capability.For the physical characteristics of the guide wire,a physical model of the guide wire and the flexible deformation calculation method based on the finite element are proposed.The model that meets the physical deformation characteristics of the guide wire is obtained and has better simulation effect and real-time performance.(2)The collision detection and force feedback calculation methods of guide wire and vessel wall are studied.In the coarse collision detection phase,the primitives of the guide wire and blood vessels are divided into lots of bounding boxes(AABB)along the axis coordinates and its binary tree is established.In the fine detection stage,the geometric cross of the elements in the intersected AABB bounding boxes is detected and accurate collision data is obtained with good real-time performance.In this thesis,a nonlinear force feedback calculation method for collision between guide wire and blood vessel is proposed.It regards the contact point as a rigid ball that can be moved and contacted and establishes a linear mechanical relationship among the contact area,the contact area center of mass,and the ball center,then a simple and effective real-time force feedback calculation method is obtained.(3)Based on force feedback interactive equipment and medical image simulation engine,a virtual training system is designed for the remote operation of vascular interventional surgery by using C++ and QT platform.After systematic experimental tests,the surgical training simulation process of the guide wire interventional blood vessel is completed and the tactile feedback and visual feedback of the surgical virtual training system are realized.Finally,the main work contributions and research results of this paper are summarized and future research works about this topic are discussed.