Abstract: Discrete finite element was used as basic unit to simulate and predict deformation of the whole elastomer for complexity of soft tissue deformation in medical image. The process of registration was regarded as solving 2D stress problem by finite element method. The finite element energy function was also improved. Mutual Information (MI) with high accuracy and robustness was selected as metric for solving equation. In order to improve registration efficiency, registration process was optimized by the multi-resolution strategy. By registration experiment for medical images in radiotherapy and comparison with the existing methods, better registration results were obtained. The proposed registration method is more sensitive to the rigid displacement and with improvement in speed. All that shows this registration method is of high precision and efficiency.

Key words: finite element, Mutual Information (MI), multi-resolution

摘要： 针对医学图像中软组织形变复杂多样的特点，在配准过程中以离散化的有限单元为基本单位模拟和预测整个弹性体产生的形变，将配准过程视为有限元求解二维平面应力问题并对有限元能量函数进行改进，选取高精度和鲁棒性良好的互信息(MI)为测度应用到方程求解中。为提高算法效率，在配准过程中采用多分辨率策略进行优化。通过对放疗中医学图像进行配准实验并与已有方法进行比较，得到的配准结果更优，对刚体位移更敏感并提高了速度，表明该方法是一种具有高精度和高效率的配准方法。

关键词: 有限元, 互信息, 多分辨率