Panta R, Segars W, Yin F, Cai J
University of Heidelberg, Mannheim, Germany.
Department of Radiology, Duke University Medical Center, Durham, NC, USA.
Med Phys. 2012 Jun;39(6Part8):3686. doi: 10.1118/1.4734981.
To characterize and implement the 4D Integrated Extended Cardiac Torso (XCAT) digital phantom for 4D radiotherapy (RT) application.
A computer program was developed to facilitate the characterization and implementation of the 4D XCAT phantom. The program can (1) generate 4D XCAT images with customized parameter files; (2) review 4D XCAT images; (3) generate composite images from 4D XCAT images; (4) track motion of selected region-of-interested (ROI); (5) convert XCAT raw binary images into DICOM format; (6) analyze clinically acquired 4DCT images and Real-time Position Management (RPM) respiratory signal. Validation of the motion tracking algorithm was made by comparing to manual method. Major characteristics of the 4D XCAT phantom were studied including the dependence of lesion motion on its location/size and inputted diaphragm profile. An end-to-end test from image generation to treatment planning was also performed.
The comparison between motion tracking and manual measurements of lesion motion trajectory showed a small difference between the two (mean difference in motion amplitude: 1.2 mm). The maximum lesion motion decreased nearly linearly (R2=0.97) as its distance to the diaphragm (DD) increased. At any given DD, lesion motion amplitude increased nearly linearly (R2 range: 0.89 to 0.95) as the inputted diaphragm motion increased. For a given diaphragm motion, the lesion motion is independent f the lesion size at any given DD. The 4D XCAT phantom can closely reproduce irregular breathing profile: the mean difference in motion amplitude between the inputted and the measured motion profile was 1.4 mm. The end-to-end test showed that clinically comparable treatment plans can be generated successfully based on 4D XCAT images.
An integrated computer program has been developed to generate, review, analyze, process, and export the 4D XCAT images. A robust workflow has been established to implement the 4D XCAT phantom for 4D RT application.
对用于四维放射治疗（RT）的四维集成扩展心脏体模（XCAT）进行特性描述并实现其应用。
开发了一个计算机程序以促进四维XCAT体模的特性描述和实现。该程序能够（1）使用定制参数文件生成四维XCAT图像；（2）查看四维XCAT图像；（3）从四维XCAT图像生成合成图像；（4）跟踪选定感兴趣区域（ROI）的运动；（5）将XCAT原始二进制图像转换为DICOM格式；（6）分析临床采集的四维CT图像和实时位置管理（RPM）呼吸信号。通过与手动方法比较对运动跟踪算法进行了验证。研究了四维XCAT体模的主要特性，包括病变运动对其位置/大小以及输入的膈肌轮廓的依赖性。还进行了从图像生成到治疗计划的端到端测试。
病变运动轨迹的运动跟踪与手动测量之间的比较显示两者之间差异较小（运动幅度的平均差异：1.2毫米）。随着病变到膈肌的距离（DD）增加，病变的最大运动几乎呈线性下降（R2 = 0.97）。在任何给定的DD下，随着输入的膈肌运动增加，病变运动幅度几乎呈线性增加（R2范围：0.89至0.95）。对于给定的膈肌运动，在任何给定的DD下，病变运动与病变大小无关。四维XCAT体模能够紧密再现不规则呼吸轮廓：输入和测量的运动轮廓之间的运动幅度平均差异为1.4毫米。端到端测试表明，基于四维XCAT图像可以成功生成临床可比的治疗计划。
已开发出一个集成计算机程序来生成、查看、分析、处理和导出四维XCAT图像。已建立了一个强大的工作流程来实现用于四维RT应用的四维XCAT体模。
