Study On A Novel VR-based Doctortraining System For Vascular Interventional Surgery

Nowadays, cardiovascular and cerebrovascular disease has become a serious threat to human life. Minimally invasive surgery technology is one of the most effective methods to treat this disease timely. However, the procedure of the operation is complexity and has a high risk, this situation requires the doctor to be trained enough before clinic surgery. The doctors who can finish the vascular interventional surgery are not enough. So we should employ an appropriate and effective training method to train the doctors before surgery. With the development of computer technique, virtual reality(VR) technology has been used in medical field. This paper is a research about a novel vascular interventional surgery training system based on VR. We have set up a foundation platform. Utilizing this system the operator can practice to operate the vascular interventional surgery assistant system, in this way to improve surgery skills.This paper has finished the MFC single document application using the 3D graphics interface Open GL in the environment of VC++6.0. This application programming can realize preliminary processing of 3D model, such as importing and displaying the model, displaying the coordinate axis, transforming the view angle, etc. We have finished the geometric model of vascular interventional surgery virtual environment. The 3DS MAX software has been used to build the model of environment and render visual effect. In order to simulate the surgery environment more realistically, 3D reconstruction method based on CT scanning files has been used to build the vascular model. In this paper, mass-spring model has been used to finish the physical model in this research, and we have established the dynamics equation of the moving particle. Then the objects possess the characteristics of soft tissue, when they collide, soft tissue deformation produces. In this research, Bullet physics engine has been used to complete physical model. Otherwise, AABB is the most suitable method to process the collision problem between deformable objects. We obtain this method to determine whether collision occurs and confirm the collision point further. According to the change of the collision point position we can calculate the feedback force.This paper establishes and improves the calculation model of feedback force. This model not only contains the collision force on the front of the catheter, also contains the friction force between the catheter and the vascular wall and the resistance of the blood flow. The force rendering library Open Haptics has been applied to complete feedback force rendering. The haptic device PHANTOM Premium, produced by sensible company, is used to realize two-way force information interaction between the virtual environment and reality. However, the operation process of PHANTOM is different from the real surgery process. To simulate the real surgery process and conform to the habit of doctor, this paper applies a novel master manipulator, which is designed using magnetorheological fluid(MRF) to realize force feedback. The doctor can operate the real catheter using this manipulator as the human-computer interaction platform, which will improve the reality of the training system.We have carried on a series of experiments on this novel VR system. The results prove that this system can realize position tracking with high consistent and produce feedback force accurately. In our research, we apply the modern computer technique to medical field. And complete the foundation platform. This system can train the operation skills of vascular interventional surgery.