Leszczynski K, Loose S
Department of Medical Physics, Northeastern Ontario Regional Cancer Centre, Sudbury, Canada.
Int J Biomed Comput. 1995 Sep;40(1):59-67. doi: 10.1016/0020-7101(95)01125-x.
An automated method for quantitative evaluation of geometric accuracy of radiation field placement during radiation therapy treatments has been developed and is presented in this article. The method is based on matching polygons representing the boundaries of the prescribed and treated radiation fields. An efficient algorithm for finding the intersection of two arbitrary simple polygons has been developed for that purpose. The process of polygon matching is performed by iterative optimization of the goodness-of-match measure derived from the area of the intersection between the two polygons to be matched. The optimization is done with respect to the translation and rotation in the plane that are applied to the polygon representing the treated field. The optimum translation and rotation define the adjustments in the position of the treated field, relative to the patients anatomy, which are necessary in order to bring the treated field into the best possible agreement with the prescription. The radiation field matching scheme was applied to a clinical dataset consisting of prescription-treatment field pairs extracted from simulation and portal images for 40 patients. It is concluded that the observed accuracy and efficiency of the method make it very suitable for applications in radiation therapy verification.
本文介绍了一种已开发出的用于在放射治疗过程中对辐射野放置的几何精度进行定量评估的自动化方法。该方法基于匹配代表规定辐射野和治疗辐射野边界的多边形。为此已开发出一种用于找到两个任意简单多边形交点的高效算法。多边形匹配过程通过对从要匹配的两个多边形之间的交叠区域得出的匹配优度度量进行迭代优化来执行。优化是针对应用于代表治疗野的多边形的平面中的平移和旋转进行的。最佳平移和旋转定义了治疗野相对于患者解剖结构的位置调整，这是使治疗野与处方达到最佳契合所必需的。辐射野匹配方案应用于一个临床数据集，该数据集由从40名患者的模拟图像和射野图像中提取的处方 - 治疗野对组成。得出的结论是，该方法所观察到的准确性和效率使其非常适合用于放射治疗验证。
