Research On Minimally Invasive Surgery System With Virtual Reality Technology

Minimally Invasive Surgery is the trend of modern medical service. The research and development of Virtual Minimally Invasive Surgery (VMIS) can not only cut down the expense and the time of training a qualified surgeon, but also reduce the chance of surgery venture. So VMIS has significant meaning for the improvement of medical education and medical treatment. This thesis surveys the current status of VMIS system, outlines the system's structure and modules. Several key techniques existing in VMIS system are studied in the thesis work.For geometrical modeling, we design the geometrical models of related human organs and surgery apparatus by 3DS MAX and SolidWorks, save the models as the ASE and STL format file, then rebuild these models in the circumstance of OpenGL through compiling the C++ interface programs.In the aspect of physical modeling, this thesis proposed a linear elastic model, the human organ is discrete to a mass-spring-damper system, so we can use stiffness coefficient, damping coefficient, and mass point density to represent the characters of the human organ. The topology of the tissue is described by the adjacent tables, and the dynamical equations can be constructed based on the data stored in the adjacent tables. The Euler method is used to integrate the equations of deformation and feed-back force.In the study of collision detection, using effective hierarchical bounding volume algorithm and vector method to realize the real-time collision detection in complex environment of virtual surgery, if a collision is occurred find out the intersection point and calculate feedback force value. This paper also has some study on virtual surgery instruments and force feedback device.Finally, we established the VMIS software platform developed by VC and OpenGL which running under Windows XP operating system, designed several VMIS training schemes, to simulate and verify the key techniques above all.