Research On The Computer-aided Orthopedic Surgery System Based On Three-dimensional Reconstruction

With the development of computer and information technology in medical field, thesystem for computer-aided surgery is becoming a hotspot on a biomedical engineering field.With the auxiliary support of these techniques in the preoperative, intraoperative andpostoperative surgical, surgeons can improve the surgical positioning accuracy, reducingsurgical trauma and improving the success rate of surgery. In computer-aided orthopedicsurgery system, three-dimensional model of the bone tissue and simulated operation is thepremise and the base of other aided technology. By measuring, cutting, positioning thethree-dimensional model on computer before surgery, doctors can be familiar with surgicalprocedures, improve the accuracy of the forecasts of the surgical effect, so that they canmodify the surgery programs in the planning process, improve the quality of operation, andreduce costs.In recent years, many researchers around the world are dedicated to the related research.This paper try to make some improvements based on the existing theory and application ofcomputer-aided orthopedic surgery, and to develop such a systems, mainly focusing on thefollowing subjects：1) About the three-dimensional reconstruction, after comparison the MC algorithm withthe method based on the outline of the connection, the classical MC algorithm is used toreconstruct the medical images. For improving the ambiguity during reconstruction, andsmooth effect, the methods of asymptote and smooth vector fields are used, respectively.2) As point scanning method to generate rapid prototyping file is not suitable for medicalimage, a method based on the MC algorithm to generate the STL file is proposed,which caneasily and quickly output STL files used for the manufacture of the solid model.3) As clicking with the mouse model on a computer screen cannot get the depthinformation, this paper presents a picking ray with triangle intersection method to obtainaccurate three-dimensional space information on three-dimensional model. Based on thecoordinates of selecting points, a series operation can be done on three-dimensional model,such as measuring, labeling, cutting surface in enclosed area, model relocation, and so on. Butthe methods of ray selecting points and cutting model needs to traverse all the triangles, whichis time-consuming, so a mesh bounding box method is proposed to rapidly remove a largenumber of unrelated triangle, to avoid its rays or cutting the surface of the calculation, whichcan significantly improve the interaction speed.4) A computer-aided orthopedic surgery system is developed, which can parse DICOM files, show coronal、sagittal plane,reconstruct3D model, generate rapid prototyping file, anda series orthopedic surgery simulation operation is available to meet the basic requirement ofcomputer aided orthopedic surgery.