Study On Image-based MCNP Modeling And Simulation Of Digital Human

As the development of human anatomy and radiation oncology physics, computer aided diagnostic therapy which is based on medical images (such as CT, MRI ) is more and more useful in practice. There are several ways of radiation therapy, and the most advanced way is the technique of intensity modulation radiation therapy. The way exists some problems such as orientation of CT machine, fixation of human body, and imprecision of dose calculation, etc. The patient model adopted in the existing commercial radiotherapy planning system is based on water material with inhomogeneities and skin curvature correction. Accurate patient model is needed for dose calculation using MCNP, and the calculation will be time-consuming. The author elementarily studied how to finish visualization of medical images by using VTK, and primarily studied how to build the patient model to make MCNP calculate more precisely.The Visualization ToolKit (VTK) is an open source, freely available software system for 3D computer graphics, image processing, and visualization used by thousands of researchers and developers around the world. The visualization technique of medical images includes two parts: volume rendering and surface rendering. They have respective characteristics and application fields. It could greatly simplify the problem about reconstruction of medical images to use VTK. MCNP is a general-purpose Monte Carlo N-Particle code that can be used for neutron, photon, electron, or coupled neutron/photon/electron trans-port, including the capability to calculate eigenvalues for critical systems.The main contribution of this dissertation includes:1. Study of two rendering methods and the algorithm of visualization of medical images by using VTK.2. Introduction of an image-based brain model which can be applied in dose calculation using MCNP. The key algorithm in MCNP modeling named as "voxel uniting" contains two methods.3. The algorithm solves the problem of time consuming and limit of the amount of cells, and its function & validity are proved by some examples.