Multiple breath-hold CBCT for online image guided radiotherapy of lung tumors: Simulation with a dynamic phantom and first patient data
Multiple breath-hold CBCT for online image guided radiotherapy of lung tumors: Simulation with a dynamic phantom and first patient data
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DOI：
10.1016/j.radonc.2011.01.019
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发表时间：
2011-03-01
影响因子：
5.7
通讯作者：
McNair, Helen
中科院分区：
文献类型：
--
作者：
Boda-Heggemann, Judit;Fleckenstein, Jens;McNair, Helen
背景与目的：计算机控制的屏气可有效减少肺部肿瘤影像引导精确放疗中的器官运动。然而，3D锥形束CT（CBCT）的采集时间超过了最大屏气时间。我们开发了一种方法，能够利用基于主动呼吸控制（ABC®）屏气的CBCT图像采集进行在线验证。
方法：基于ABC®重复屏气采集患者的CBCT图像。还用运动体模模拟临床情况。仅选择自由呼吸和屏气投影对患者和体模图像进行重建。
结果：重复屏气时的CBCT成像使体模中模拟肿瘤的结构呈现出精确的球形外观。可以清晰地区分一个模糊的“幻影”结构（自由呼吸阶段）。患者屏气时间的平均百分比为66%。仅基于自由呼吸的重建显示肿瘤和膈肌模糊，仅基于屏气投影的重建使相同结构轮廓清晰。从体模实验估计，每个方向的最大重新定位误差为1毫米。
讨论与结论：重复屏气期间的CBCT提供了可靠的基于软组织的定位。一次屏气期间的快速3D成像目前正在开发中，有可能加速基于临床直线加速器的容积成像。（C）2011爱思唯尔爱尔兰有限公司。保留所有权利。《放射治疗与肿瘤学》98（2011）309 - 316
Background and Purpose: Computer controlled breath-hold effectively reduces organ motion for image-guided precision radiotherapy of lung tumors. However, the acquisition time of 3D cone-beam-CT (CBCT) exceeds maximum breath-hold times. We have developed an approach enabling online verification using CBCT image acquisition with ABC (R)-based breath-hold.Methods: Patient CBCT images were acquired with ABC (R)-based repeat breath-hold. The clinical situation was also simulated with a Motion Phantom. Reconstruction of patient and phantom images with selection of free-breathing and breath-hold projections only was performed.Results: CBCT-imaging in repeat breath-hold resulted in a precisely spherical appearance of a tumor-mimicking structure in the phantom. A faint "ghost" structure (free-breathing phases) can be clearly discriminated. Mean percentage of patient breath-hold time was 66%. Reconstruction based on free-breathing-only shows blurring of both tumor and diaphragm, reconstruction based on breath-hold projections only resulted in sharp contours of the same structures. From the phantom experiments, a maximal repositioning error of 1 mm in each direction can be estimated.Discussion and Conclusion: CBCT during repetitive breath hold provides reliable soft-tissue-based positioning. Fast 3D-imaging during one breath-hold is currently under development and has the potential to accelerate clinical linac-based volume imaging. (C) 2011 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 98 (2011) 309-316