| Radiotherapy is a branch of medical science which uses radiation, predominantly to treat malignant disease. The aim of radiotherapy technique is to improve the carcinogenic cell destruction while reducing at best the undesirable effects onto the neighboring healthy tissue. Conformal radiotherapy can reach this aim perfectly. One way to treat carcinogenic cell is coupled grating, the other is casting lead block. Unfortunately, there are disadvantages in these two methods respectely. To overcome these problems the digital conformal lead block technology is proposed, and computer aided design technology is applied in the field in this dissertation.The technology for designing the conformal lead block is a part of technique development work of the digital conformal lead block technology. The dissertation points out two important sections in design stage, which includes modeling and ACIS based structuring. According to characters of the conformal lead block shape,ruled surface and B-Spline curve are used to express the side shape of the conformal lead block and profiles of the two end planes, respectively.In the dissertation, the system for ACIS based conformal lead block design technology has been developed and the aim is at the actual demand of the clinic equipment. The system is designed with the object-oriented theory, and is realized by means of programming language Visual C++6.0 and graphics software ACIS.In the last step, with a practical machining sample application to the technology development, the system is prove to be accurate and feasible in this paper. |
