Cai J, Zhou S Q, Hopkinson J, Saxena V A, Chu J
Department of Medical Physics, Rush Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
Med Phys. 1996 Dec;23(12):2069-75. doi: 10.1118/1.597844.
A least square fitting algorithm for alignment of multi-open-curved segments and point pairs of anatomical features obtained from both portal images and simulation radiographs has been developed for patient position verification in radiation therapy. A coordinate system associated with each curved segment pair is constructed so that the discrepancies of each segment pair can be obtained easily. The algorithm allows users to select not only multiple curve pairs but also individual point pairs on the important anatomic landmarks. The misregistration is measured by the sum of the position deviation of individual point pairs and ordinate discrepancies of all segment pairs from their corresponding coordinate systems. A mathematical minimization method is applied to seek an optimal transformation for matching of all segment and/or point pairs involved. The reliability of the algorithm has been tested with both phantom and clinical images. The test results indicate that the typical errors are less than 1 mm and 1 degrees in translation and rotation, respectively.
已开发出一种最小二乘拟合算法，用于对从门静脉图像和模拟射线照片中获取的多段开放曲线和解剖特征点对进行对齐，以用于放射治疗中的患者位置验证。构建与每个曲线段对相关联的坐标系，以便能够轻松获得每个段对的差异。该算法允许用户不仅选择多个曲线对，还可以选择重要解剖标志上的单个点对。配准误差通过单个点对的位置偏差之和以及所有段对与其相应坐标系的纵坐标差异来衡量。应用数学最小化方法来寻求用于匹配所有相关段和/或点对的最佳变换。该算法的可靠性已通过体模和临床图像进行测试。测试结果表明，在平移和旋转方面，典型误差分别小于1毫米和1度。
