The Visual System Development Of Cranial Prosthesis

Congenital malformations, decompressive craniectomy, open brain injury and some other reasons may cause skull defects which lead to brain dysfunction, affect craniofacial appearance and bring significant psychological and physical harm to patients. With the development of biological science, medical imaging and digital design, personal and digital designed prostheses are in large requirement in order to improve the quality of patients'life.In this paper, based on the raw CT data of the defective skull, MFC framework is constructed in the VC++ 6.0 with the help of VTK and the interface problem is solved between VTK and MFC. The digital image processing and real-time visualization display are achieved. Laplacian, Sobel and other signal processing operators are used to filter noise removal and highlight the interest regions on the two-dimensional image.The exact contours of the target areas are obtained by the threshold segmentation with the Roberts, LOG, and other edge detection operators.Because the spatial location of skull is difficult to express just by the two-dimensional sections, the three-dimensional model of defective skull is obtained by the surface rendering algorithm in VTK in this paper. The options such as selected movement, scale, rotation to multidirectional real-time observation can be realized in the visual system.The STL data transform function is added in this system, solving the data interface problem between medical and surface model. The STL file of the defective skull is put into the reverse engineering software Geomagic. Through discrete point cloud preprocessing, polygon modeling to achieve hole-filling, the prosthesis NUBRS surface is generated. The original point cloud data and NUBRS surface of the prosthesis are both put into the Qualify software. The errors are acceptable to ensure fitting the design requirements.The digital design of the cranial prosthesis is made by using Pro/E software and the NC machining simulation of the cranial prosthesis is made by using Pro/NC module. In order to achieve the digital manufacturing, the NC code is transferred to the CNC machine through the interface technology.The patient data management subsystem is designed by the SQL Server 2000 database. The form management for the relevant information in the whole processing is achieved and the processing such as real-time add, modify and delete are added in order to improve management efficiency.