Research On Photon Beam Dose Calculation And Visualization In Radiation Treatment Planning System

Radiotherapy is one of the important therapeutic means for tumor therapy. Radiation treatment planning system,especially the dose calculation and visulization, plays a great important role in the implemention of precise radiotherapy and the development of new style radiotherapy technologies. With the development of related disciplines and radiotherapy technologies, radiation treatment planning system has become one hot spot in the field of radiotherapy reserch. In this paper, both photon dose calculation and its visulization technology have been deeply studied, image segmentation technology which is closely related to dose calculation has also been studied. A photon beam dose calculation and visulization software was developed on Visual C++ platform, the functions include database management, DICOM image browse, image segmentation, 3D reconstruction, photon dose calculation and visulization, etc.As the basis of 3D reconstruction, dose calculation and visulization, the image segmentation technologies have been studied. The Live Wire semi-automation segmentation algorithm was deeply studied and its cost function was modified and improved. The results show that the boundary of interest tissue could be extracted quickly and accurately.As the core of the radiation treatment planning system, the photon dose calculation algorithm was deeply studied. After the introduction and analysis of the physical basis of radiotherapy, collapsed cone convolution algorithm for photon dose calculation was deeply investigated. The algorithm has been developed on Visual C++ platform, the dose in patient is calculated iteratively and worked out in several seconds. To verify the accuracy of the algorithm, we compared the dose calculated by the developed algorithm with that by DOSXYZnrc Monte Carlo program with the same parameters. The results show that the accuracy and speed of the developed collapsed cone convolution method are satisfied.As one of the important dose evaluation tools, both 2D and 3D dose visulization technogies were studied. Marching cubes algorithm was implemented for 3D isodose sufurce visulization, and grid tracing algorithm was implemented for 2D isodose line visulization. The results show that Marching cubes algorithm fits well 3D isodose surface visulization, and grid tracing algorithm is suitable for 2D isodose line visulization.