Lüddemann Tobias, Egger Jan
Technical University of Munich , Department of Mechatronics, 85748 Garching bei Munich, Bavaria, Germany.
Graz University of Technology, Institute for Computer Graphics and Vision, 8010 Graz, Styria, Austria; BioTech-Med-Graz, 8010 Graz, Styria, Austria.
J Med Imaging (Bellingham). 2016 Apr;3(2):024004. doi: 10.1117/1.JMI.3.2.024004. Epub 2016 Jun 20.
Among all types of cancer, gynecological malignancies belong to the fourth most frequent type of cancer among women. In addition to chemotherapy and external beam radiation, brachytherapy is the standard procedure for the treatment of these malignancies. In the progress of treatment planning, localization of the tumor as the target volume and adjacent organs of risks by segmentation is crucial to accomplish an optimal radiation distribution to the tumor while simultaneously preserving healthy tissue. Segmentation is performed manually and represents a time-consuming task in clinical daily routine. This study focuses on the segmentation of the rectum/sigmoid colon as an organ-at-risk in gynecological brachytherapy. The proposed segmentation method uses an interactive, graph-based segmentation scheme with a user-defined template. The scheme creates a directed two-dimensional graph, followed by the minimal cost closed set computation on the graph, resulting in an outlining of the rectum. The graph's outline is dynamically adapted to the last calculated cut. Evaluation was performed by comparing manual segmentations of the rectum/sigmoid colon to results achieved with the proposed method. The comparison of the algorithmic to manual result yielded a dice similarity coefficient value of [Formula: see text], in comparison to [Formula: see text] for the comparison of two manual segmentations by the same physician. Utilizing the proposed methodology resulted in a median time of [Formula: see text], compared to 300 s needed for pure manual segmentation.
在所有类型的癌症中，妇科恶性肿瘤是女性中第四常见的癌症类型。除了化疗和外照射放疗外，近距离放射治疗是治疗这些恶性肿瘤的标准程序。在治疗计划过程中，通过分割将肿瘤作为靶区以及确定相邻的危险器官，对于在保护健康组织的同时实现对肿瘤的最佳放射剂量分布至关重要。分割是手动进行的，在临床日常工作中是一项耗时的任务。本研究聚焦于妇科近距离放射治疗中作为危险器官的直肠/乙状结肠的分割。所提出的分割方法使用一种基于图形的交互式分割方案和用户定义模板。该方案创建一个有向二维图形，随后在该图形上进行最小成本封闭集计算，从而勾勒出直肠轮廓。图形轮廓会根据最后计算的切割结果动态调整。通过将直肠/乙状结肠的手动分割与所提方法得到的结果进行比较来进行评估。算法结果与手动结果的比较得出的骰子相似系数值为[公式：见原文]，而同一医生的两次手动分割结果比较的该系数值为[公式：见原文]。使用所提方法的中位时间为[公式：见原文]，而单纯手动分割需要300秒。
