Yan Hui, Yin Fang-Fang, Kim Jae Ho
Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan 48202, USA.
Med Phys. 2003 Dec;30(12):3052-60. doi: 10.1118/1.1626122.
A phantom study was conducted to investigate inherent positioning accuracy of an image-guided patient positioning system-the Novalis Body system for three-dimensional (3-D) conformal radiotherapy. This positioning system consists of two infrared (IR) cameras and one video camera and two kV x-ray imaging devices. The initial patient setup was guided by the IR camera system and the target localization was accomplished using the kV x-ray imaging system. In this study, the IR marker shift and phantom rotation were simulated and their effects on the positioning accuracy were examined by a Rando phantom. The effects of CT slice thickness and treatment sites on the positioning accuracy were tested. In addition, the internal target shift was simulated and its effect on the positioning accuracy was examined by a water tank. With the application of the Novalis Body system, the positioning error of the planned isocenter was significantly reduced. The experimental results with the simulated IR marker shifts indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.5 +/- 0.2, and 0.7 +/- 0.2 mm along the lateral, longitudinal, and vertical axes, respectively. The experimental results with the simulated phantom rotations indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.7 +/- 0.2, and 0.5 +/- 0.2 mm along the three axes, respectively. The experimental results with the simulated target shifts indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.7 +/- 0.2, and 0.5 +/- 0.2 mm along the three axes, respectively. On average, the positioning accuracy of 1 mm for the planned isocenter was achieved using the Novalis Body system.
进行了一项体模研究，以调查图像引导患者定位系统——用于三维（3-D）适形放疗的Novalis Body系统的固有定位精度。该定位系统由两个红外（IR）摄像机、一个视频摄像机和两个kV X射线成像设备组成。初始患者摆位由IR摄像机系统引导，靶区定位使用kV X射线成像系统完成。在本研究中，模拟了IR标记移位和体模旋转，并通过Rando体模检查了它们对定位精度的影响。测试了CT切片厚度和治疗部位对定位精度的影响。此外，模拟了内部靶区移位，并通过水箱检查了其对定位精度的影响。应用Novalis Body系统后，计划等中心的定位误差显著降低。模拟IR标记移位的实验结果表明，计划等中心在横向、纵向和垂直轴上的定位误差分别为0.6±0.3、0.5±0.2和0.7±0.2mm。模拟体模旋转的实验结果表明，计划等中心在三个轴上的定位误差分别为0.6±0.3、0.7±0.2和0.5±0.2mm。模拟靶区移位的实验结果表明，计划等中心在三个轴上 的定位误差分别为0.6±0.3、0.7±0.2和0.5±0.2mm。使用Novalis Body系统平均可实现计划等中心1mm的定位精度。
