Reduction of organ motion in lung tumors with respiratory gating
Reduction of organ motion in lung tumors with respiratory gating
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DOI：
10.1016/j.lungcan.2005.08.008
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发表时间：
2006-01-01
期刊：
影响因子：
5.3
通讯作者：
Rosenzweig, KE
中科院分区：
文献类型：
--
作者：
Giraud, P;Yorke, E;Rosenzweig, KE
我们评估了商业呼吸门控系统在呼吸同步CT（RS-CT）扫描中确保内部解剖结构再现性的能力。该被动系统使用红外敏感相机来跟踪安装在腹部上的反射标记的运动。选择18名患者（9名肺肿瘤患者和9名肝肿瘤患者）评价瓦里安实时位置监测呼吸门控系统。选择肝脏肿瘤作为下叶肿瘤的替代物。每例患者在吸气末（EI）或呼气末（EE）至少进行两次相同的RS-CT扫描，以评估分次内再现性。12名患者还接受了自由呼吸扫描和反向呼吸相位同步扫描（如果前两个是EE，则进行EI，反之亦然）。在每个CT上，医生描绘肝脏患者的肝脏、肾脏、脾脏和横膈膜;类似地，描绘肺部患者的肺部、总肿瘤体积（GTV）、气管、心脏和横膈膜。在使用骨解剖学配准不同的CT图像后，根据其体积、质心位移（COM）和再现性“指数”系数来量化各个数据集之间的每个结构的变化。对在El和EE阶段获得的CT扫描进行分析，得出膈肌位置的平均上下（SI）差为14.4 mm（范围：45.9-0.9）。对在相同呼吸时相采集的CT扫描进行类似分析，结果为0.7 mm（范围：3.1-0，p=0.0001）。对肺、心、肺的GTV、肝、脾和肾的组成部位进行分析也得到了类似的结论。肺、肝和脾的体积变化的评价证实了RS-CT的再现性，而“指数”系数证实了所有器官的RS-CT的再现性。商业门控系统使用外部标记的RS-CT显着提高了胸部和上腹部结构的位置再现性。器官运动的这种可再现的减少将允许扩张裕度的减少，从而促进靶剂量的增加超过常规放射治疗所允许的剂量。(C)2005爱思唯尔爱尔兰有限公司保留所有权利。
We evaluated the ability of a commercial respiratory gating system to assure the reproducibility of internal anatomy in respiration synchronized CT (RS-CT) scans. This passive system uses an infrared sensitive camera to track the motion of reflective markers mounted on the abdomen. Eighteen patients, nine with lung tumors and nine with liver tumors, were selected for evaluation of the Varian Real-Time Position Monitor respiratory gating system. Liver tumors were chosen as surrogate for lower lobe tumors. Each patient underwent at least two identical RS-CT scans, at end-inspiration (EI) or end-expiration (EE), to assess intrafraction reproducibility. Twelve patients also underwent a free breathing scan and an opposed-respiration phase synchronized scan (EI if the two first were an EE and vice versa). On each CT, a physician contoured the liver, the kidneys, the spleen, and the diaphragms for the liver patients; and similarly, the lungs, the gross tumor volume (GTV), the trachea, the heart and the diaphragms for the lung patients. After registering the different CT images using bony anatomy, the changes of each structure between the respective data sets were quantified in terms of its volume, the displacement of its center of mass (COM), and an "index" coefficient of reproducibility. An analysis of the CT scans obtained at El and EE phases yielded an average superior-inferior (SI) difference of the diaphragm position of 14.4 mm (range: 45.9-0.9). A similar analysis of CT scans acquired at the same breathing phase yielded 0.7 mm (range: 3.1-0, p=0.0001). Similar conclusions were derived in analysis of COM positions of the following structures: lungs, heart, lung's GTV, liver, spleen and kidneys. Evaluation of volume changes for lungs, liver, and spleen confirmed reproducibility of RS-CT while the "index" coefficient confirmed reproducibility of RS-CT of all organs. A commercial gating system using external markers for RS-CT significantly improves the positional reproducibility of thoracic and upper abdominal structures. This reproducible decrease in organ motion will allow a reduction of the margin of expansion facilitating increase in target dose beyond that allowed by conventional radiation treatments. (C) 2005 Elsevier Ireland Ltd. All rights reserved.