Mohan R, Brewster L J, Barest G D
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Med Phys. 1987 Nov-Dec;14(6):1048-52. doi: 10.1118/1.595984.
Graphical displays of three-dimensional dose distribution data are often too complex to be easily assimilated and interpreted for the evaluation of radiation treatment plans. Histograms showing dose versus volume are convenient and useful tools for summarizing dose distribution information throughout the entire volume of a given anatomic structure. They can quickly highlight characteristics such as dose uniformity and hot and cold spots, and can be used to produce statistics including tumor control and normal tissue complication probabilities. To obtain a dose volume histogram for a given structure, it may be necessary to examine its spatial relationships with neighboring structures. They may overlap, be completely disjoint, or one may be contained within another. To resolve potential ambiguities, a procedure has been developed that assigns hierarchies to anatomical structures for the purpose of histogram calculation. The hierarchy assigned to each structure is used to determine the structure within which a given dose matrix point is considered to lie. In this manner, regions of structure intersection are assigned to one object or another, and dose volume histograms can be calculated for each structure separately. From this framework, addition and subtraction of histograms can also be performed. Details of the algorithm are presented along with an example using patient data.
三维剂量分布数据的图形显示通常过于复杂，难以轻松地被吸收和解释以用于评估放射治疗计划。显示剂量与体积关系的直方图是方便且有用的工具，可用于总结给定解剖结构整个体积内的剂量分布信息。它们可以快速突出诸如剂量均匀性以及热点和冷点等特征，并且可用于生成包括肿瘤控制和正常组织并发症概率在内的统计数据。为了获得给定结构的剂量体积直方图，可能有必要检查其与相邻结构的空间关系。它们可能重叠、完全不相交，或者一个可能包含在另一个之内。为了解决潜在的模糊性，已开发出一种程序，该程序为解剖结构分配层次结构以用于直方图计算。分配给每个结构的层次结构用于确定给定剂量矩阵点被认为所在的结构。通过这种方式，结构相交区域被分配给一个或另一个对象，并且可以分别为每个结构计算剂量体积直方图。基于此框架，还可以进行直方图的加法和减法运算。本文将介绍该算法的详细信息，并给出一个使用患者数据的示例。
