Feature-based rectal contour propagation from planning CT to cone beam CT
Feature-based rectal contour propagation from planning CT to cone beam CT
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DOI：
10.1118/1.2975230
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发表时间：
2008-10-01
期刊：
影响因子：
3.8
通讯作者：
Xing, Lei
中科院分区：
文献类型：
--
作者：
Xie, Yaoqin;Chao, Ming;Xing, Lei
这项工作的目的是开发一种新的基于特征的配准策略，自动映射直肠轮廓从计划计算机断层扫描（CT）（pCT）锥束CT（CBCT）。在pCT上手动勾画直肠轮廓。然后构造一个以轮廓为内表面的窄带，以便在配准过程中排除直肠内的体积。采用基于特征的配准算法在CBCT中找到对应的轮廓，该算法包括两个步骤：（1）根据周围组织的特征在pCT和CBCT中自动搜索控制点，并利用尺度不变性特征变换匹配相应的控制点;（2）利用薄板样条变换的控制点对窄带进行翘曲，并将相应的轮廓从pCT映射到CBCT。建议的轮廓传播技术应用于数字幻影和临床病例，在所有情况下，轮廓映射结果被认为是临床上可以接受的。对于临床病例，即使在pCT和CBCT扫描之间存在显著的直肠内容物变化时，该方法也获得了令人满意的结果。因此，变形配准后的直肠体积和手动分割的直肠之间的一致性被发现超过90%。所提出的技术提供了一个强大的工具，在未来的前列腺，直肠和妇科癌症的自适应放射治疗。(C)2008年美国医学物理学家协会。
The purpose of this work is to develop a novel feature-based registration strategy to automatically map the rectal contours from planning computed tomography (CT) (pCT) to cone beam CT (CBCT). The rectal contours were manually outlined on the pCT. A narrow band with the outlined contour as its interior surface was then constructed, so that we can exclude the volume inside the rectum in the registration process. The corresponding contour in the CBCT was found by using a feature-based registration algorithm, which consists of two steps: (1) automatically searching for control points in the pCT and CBCT based on the features of the surrounding tissue and matching the homologous control points using the scale invariance feature transformation; and (2) using the control points for a thin plate spline transformation to warp the narrow band and mapping the corresponding contours from pCT to CBCT. The proposed contour propagation technique is applied to digital phantoms and clinical cases and, in all cases, the contour mapping results are found to be clinically acceptable. For clinical cases, the method yielded satisfactory results even when there were significant rectal content changes between the pCT and CBCT scans. As a consequence, the accordance between the rectal volumes after deformable registration and the manually segmented rectum was found to be more than 90%. The proposed technique provides a powerful tool for adaptive radiotherapy of prostate, rectal, and gynecological cancers in the future. (C) 2008 American Association of Physicists in Medicine.