Observation of interfractional variations in lung tumor position using respiratory gated and ungated megavoltage cone-beam computed tomography
Observation of interfractional variations in lung tumor position using respiratory gated and ungated megavoltage cone-beam computed tomography
复制标题
DOI：
10.1016/j.ijrobp.2006.11.055
复制
发表时间：
2007-04-01
影响因子：
7
通讯作者：
Amols, Howard
中科院分区：
文献类型：
--
作者：
Chang, Jenghwa;Mageras, Gig S.;Amols, Howard
目的：为了评估使用兆伏锥束计算机断层扫描（MV CBCT）来测量分次间的变化在肺tumor position.Methods和Materials：8例非小细胞肺癌患者参加了这项研究，4呼吸门控和4没有。所有患者每周进行一次MV CBCT扫描。轮廓规划CT和MV CBCT图像空间配准的基础上椎体解剖，并确定肿瘤质心的位移。通过比较每周射野正交X线片与计划CT图像生成的数字重建X线片来评估设置误差。进行假设检验，以测试的体积差，质心位移，和设置的不确定性的统计学意义。结果：椎体和肺内的肿瘤的软组织部分是可见的MV CBCT扫描。1例患者在治疗过程中观察到统计学显著性全身体积减少。模拟CT和MV CBCT扫描之间的平均质心位移分别为2.5 mm、-2.0 mm和-1.5 mm，标准差分别为2.7 mm、2.7 mm和2.6 mm（左右、前后和上下方向）。平均设置误差小于质心偏移，而标准差相当。在大多数情况下，总肿瘤体积（GTV）上定义的MV CBCT位于平均至少5毫米内的10毫米的扩张GTV上定义的规划CT scanes.Conclusions：MV CBCT技术可用于成像肺肿瘤，并可能被证明是有价值的图像引导放射治疗。鉴于患者人数较少，我们的结论必须得到验证。(c)2007爱思唯尔公司
Purpose: To evaluate the use of megavoltage cone-beam computed tomography (MV CBCT) to measure interfractional variation in lung tumor position.Methods and Materials: Eight non-small-cell lung cancer patients participated in the study, 4 with respiratory gating and 4 without. All patients underwent MV CBCT scanning at weekly intervals. Contoured planning CT and MV CBCT images were spatially registered based on vertebral anatomy, and displacements of the tumor centroid determined. Setup error was assessed by comparing weekly portal orthogonal radiographs with digitally reconstructed radiographs generated from planning CT images. Hypothesis testing was performed to test the statistical significance of the volume difference, centroid displacement, and setup uncertainty.Results: The vertebral bodies and soft tissue portions of tumor within lung were visible on the MV CBCT scans. Statistically significant systematic volume decrease over the course of treatment was observed for 1 patient. The average centroid displacement between simulation CT and MV CBCT scans were 2.5 mm, -2.0 mm, and -1.5 mm with standard deviations of 2.7 mm, 2.7 mm, and 2.6 mm in the right-left, anterior-posterior and superior-inferior directions. The mean setup errors were smaller than the centroid shifts, while the standard deviations were comparable. In most cases, the gross tumor volume (GTV) defined on the MV CBCT was located on average at least 5 mm inside a 10 mm expansion of the GTV defined on the planning CT scan.Conclusions: The MV CBCT technique can be used to image lung tumors and may prove valuable for image-guided radiotherapy. Our conclusions must be verified in view of the small patient number. (c) 2007 Elsevier Inc.