Setup variations in radiotherapy of esophageal cancer: Evaluation by daily megavoltage computed tomographic localization
Setup variations in radiotherapy of esophageal cancer: Evaluation by daily megavoltage computed tomographic localization
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DOI：
10.1016/j.ijrobp.2007.04.023
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发表时间：
2007-08-01
影响因子：
7
通讯作者：
Wong, Jeffrey Y. C.
中科院分区：
文献类型：
--
作者：
Chen, Yi-Jen;Han, Chunhui;Wong, Jeffrey Y. C.
目的：使用预处理兆伏计算机断层扫描（MVCT）扫描，以评估设置的变化，前后（AP），横向和上下（SI）方向和旋转的变化，包括俯仰，滚动和偏航，为食管癌患者治疗helical tomotherapy.Methods和材料：10例局部晚期食管癌联合放化疗使用helical tomotherapy被选中。在患者使用其皮肤纹身/标记定位后，在每次治疗前进行MVCT扫描，并根据骨骼标志自动配准到计划的千伏CT扫描。图像配准数据用于在治疗前调整患者设置。共分析了250个MVCT扫描。之间的相关性设置的变化和身体形态，包括身高，体重，相对体重变化，体表面积，和病人的年龄，evaluated.Results：在AP，横向，SI方向和俯仰，滚动和偏航旋转系统设置校正的标准偏差分别为1.5，3.7，和4.8毫米和0.5度，1.2度，和0.8度，分别。AP、侧向和SI方向以及俯仰、滚转和偏航旋转的随机设置变化的适当平均值分别为2.9、5.2和4.4 mm，以及1.0度、1.2度和1.1度。在整个放疗过程中，所有三个平移和三个旋转位移的设置变化是稳定的，幅度变化不大。没有显着的相关性之间的设置变化和身体habitus variables.Conclusions：每日MVCT扫描之前，每次治疗可以有效地检测设置错误，从而减少规划目标体积（PTV）的利润率。这将减少对关键器官的辐射剂量，并可能转化为较低的治疗相关毒性。(c)2007年爱思唯尔公司
Purpose: To use pretreatment megavoltage computed tomography (MVCT) scans to evaluate setup variations in anterior-posterior (AP), lateral, and superior-inferior (SI) directions and rotational variations, including pitch, roll, and yaw, for esophageal cancer patients treated with helical tomotherapy.Methods and Materials: Ten patients with locally advanced esophageal cancer treated by combined chemoradiation using helical tomotherapy were selected. After patients were positioned using their skin tattoos/marks, MVCT scans were performed before every treatment and automatically registered to planning kilovoltage CT scans according to bony landmarks. Image registration data were used to adjust patient setups before treatment. A total of 250 MVCT scans were analyzed. Correlations between setup variations and body habitus, including height, weight, relative weight change, body surface area, and patient age, were evaluated.Results: The standard deviations for systematic setup corrections in AP, lateral, and SI directions and pitch, roll, and yaw rotations were 1.5, 3.7, and 4.8 mm and 0.5 degrees, 1.2 degrees, and 0.8 degrees, respectively. The appropriate averages of random setup variations in AP, lateral, and SI directions and pitch, roll, and yaw rotations were 2.9, 5.2, and 4.4 mm, and 1.0 degrees, 1.2 degrees, and 1.1 degrees, respectively. Setup variations were stable throughout the entire course of radiotherapy in all three translational and three rotational displacements, with little change in magnitude. No significant correlations were found between setup variations and body habitus variables.Conclusions: Daily MVCT scans before each treatment can effectively detect setup errors and thereby reduce planning target volume (PTV) margins. This will reduce radiation dose to critical organs and may translate into lower treatment-related toxicities. (c) 2007 Elsevier Inc.