Performance studies of four-dimensional cone beam computed tomography.
Performance studies of four-dimensional cone beam computed tomography.
复制标题
DOI：
10.1088/0031-9155/56/20/013
复制
发表时间：
2011-10-21
影响因子：
3.5
通讯作者：
Chen GH
中科院分区：
文献类型：
--
作者：
Qi Z;Chen GH
四维锥形束计算机断层扫描（4DCBCT）已被提出来表征放射治疗前肿瘤的呼吸运动。然而，当所采集的锥形束投影数据被回顾性地选通到若干呼吸相位中时，用于重建每个相位的可用数据被欠采样，并且因此导致重建图像中的条纹伪影。为了解决4DCBCT中的欠采样问题，提高图像质量，已经开发了各种方法。本文提出了三种不同的4DCBCT方法的性能研究基于不同的重建算法。本文的目的是研究（1）所提取的运动轨迹的准确性与4DCBCT扫描的数据采集时间之间的关系以及（2）所提取的运动轨迹的准确性与用于对投影数据进行排序的相位箱的数量之间的关系。这些目标将被应用到三种不同的4DCBCT方法：传统的滤波反投影重建（FBP），FBP与麦金农-贝茨校正（MB）和先验图像约束压缩感知（PICCS）重建。通过将运动物体的解析投影数据叠加到来自胸部CT体积数据集的模拟投影数据，构建了由真实胸部解剖结构和具有已知3D运动轨迹的运动椭圆形物体组成的混合体模。模拟CBCT扫描与机架旋转时间从1到4分钟，并生成的投影数据被分为5，10和20相位箱，然后使用不同的方法来重建4D图像。利用快速自由变形配准算法提取运动目标的运动轨迹。对所有模拟情况下提取的运动轨迹的均方根误差（RMSE）进行了评估，以定量研究性能。结果表明：（1）更长的采集时间导致每种方法更准确的运动描绘;（2）4DCBCT需要10个或更多的相位箱，以确保肿瘤运动的足够时间分辨率;（3）为了在4分钟的数据采集时间内实现与FBP-4DCBCT相同的性能，MB-4DCBCT和PICCS-4DCBCT分别需要约2分钟和1分钟的数据采集时间。
Four-dimensional cone beam computed tomography (4DCBCT) has been proposed to characterize the breathing motion of tumors before radiotherapy treatment. However, when the acquired cone beam projection data are retrospectively gated into several respiratory phases, the available data to reconstruct each phase is under-sampled and thus causes streaking artifacts in the reconstructed images. To solve the under-sampling problem and improve image quality in 4DCBCT, various methods have been developed. This paper presents performance studies of three different 4DCBCT methods based on different reconstruction algorithms. The aims of this paper are to study (1) the relationship between the accuracy of the extracted motion trajectories and the data acquisition time of a 4DCBCT scan and (2) the relationship between the accuracy of the extracted motion trajectories and the number of phase bins used to sort projection data. These aims will be applied to three different 4DCBCT methods: conventional filtered backprojection reconstruction (FBP), FBP with McKinnon–Bates correction (MB) and prior image constrained compressed sensing (PICCS) reconstruction. A hybrid phantom consisting of realistic chest anatomy and a moving elliptical object with known 3D motion trajectories was constructed by superimposing the analytical projection data of the moving object to the simulated projection data from a chest CT volume dataset. CBCT scans with gantry rotation times from 1 to 4 min were simulated, and the generated projection data were sorted into 5, 10 and 20 phase bins before different methods were used to reconstruct 4D images. The motion trajectories of the moving object were extracted using a fast free-form deformable registration algorithm. The root mean square errors (RMSE) of the extracted motion trajectories were evaluated for all simulated cases to quantitatively study the performance. The results demonstrate (1) longer acquisition times result in more accurate motion delineation for each method; (2) ten or more phase bins are necessary in 4DCBCT to ensure sufficient temporal resolution in tumor motion and (3) to achieve the same performance as FBP-4DCBCT witha4mindata acquisition time, MB-4DCBCT and PICCS-4DCBCT need about 2- and 1 min data acquisition times, respectively.
登录
查看更多内容
影响因子：
3.5
作者：
Dietrich, Lars;Jetter, Siri;Oelfke, Uwe
通讯作者：
Oelfke, Uwe
影响因子：
3.8
作者：
Lujan, AE;Larsen, EW;Ten Haken, RK
通讯作者：
Ten Haken, RK
影响因子：
3.8
作者：
Li, Tianfang;Koong, Albert;Xing, Lei
通讯作者：
Xing, Lei
影响因子：
3.8
作者：
Chang, Jenghwa;Sillanpaa, Jussi;Amols, Howard
通讯作者：
Amols, Howard
影响因子：
3.8
作者：
SIDDON, RL
通讯作者：
SIDDON, RL