头颈部调强放疗中的机载患者定位：数字断层合成与千伏级射线照相及锥形束计算机断层扫描的比较

On-board patient positioning for head-and-neck IMRT: comparing digital tomosynthesis to kilovoltage radiography and cone-beam computed tomography.

作者信息

Wu Q Jackie, Godfrey Devon J, Wang Zhiheng, Zhang Junan, Zhou Sumin, Yoo Sua, Brizel David M, Yin Fang-Fang

机构信息

Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.

出版信息

Int J Radiat Oncol Biol Phys. 2007 Oct 1;69(2):598-606. doi: 10.1016/j.ijrobp.2007.05.045.

DOI:10.1016/j.ijrobp.2007.05.045

PMID:17869673

Abstract

PURPOSE

High-precision intensity-modulated radiotherapy demands high patient positioning accuracy. On-board digital tomosynthesis (DTS) provides three-dimensional (3D) image guidance for daily positioning with a lower imaging dose, faster acquisition, and more geometric flexibility than 3D cone-beam computed tomography (CBCT). This clinical study evaluated DTS as a daily imaging technique for patient positioning and compared the results with 3D CBCT and two-dimensional (2D) radiography.

METHODS AND MATERIALS

Head and neck cancer patients undergoing intensity-modulated radiotherapy were studied. For each session, the patient was positioned using laser marks. On-board imaging data sets, including 2D kilovoltage radiographs, DTS, and CBCT, were obtained to measure the daily patient positioning variations. The mean and standard deviations of the positioning variations in the translational and rotational directions were calculated. The positioning differences among 2D radiography, DTS, and CBCT were analyzed.

RESULTS

Image data sets were collected from 65 treatment fractions for 10 patients. The systematic patient positioning variation was <0.10 cm and 1.0 degrees one dimensionally. The random variations were 0.27-0.34 cm in the translational and 0.93 degrees -1.99 degrees in the rotational direction. The mean vector isocenter variation was 0.48 cm. DTS with 40 degrees and 20 degrees scan angles in the coronal or sagittal directions yielded the same results for patient positioning. DTS performance was comparable to that of CBCT, with positioning differences of <0.1 cm and 0.5 degrees . The positioning difference between 2D radiography and DTS was approximately 0.1 cm and 0.2 cm in the vertical/longitudinal and lateral directions.

CONCLUSION

Our results have demonstrated that DTS is a comparable 3D imaging technique to CBCT for daily patient positioning of head-and-neck patients as determined by manual registration of bony anatomy.

摘要

目的

高精度调强放疗要求患者定位具有高准确性。机载数字断层合成（DTS）可为每日定位提供三维（3D）图像引导，与三维锥形束计算机断层扫描（CBCT）相比，其成像剂量更低、采集速度更快且几何灵活性更高。本临床研究评估了DTS作为患者每日定位成像技术的效果，并将结果与3D CBCT和二维（2D）放射摄影进行了比较。

方法和材料

对接受调强放疗的头颈癌患者进行了研究。每次治疗时，使用激光标记对患者进行定位。获取包括二维千伏级射线照片、DTS和CBCT在内的机载成像数据集，以测量患者每日的定位变化。计算平移和旋转方向上定位变化的平均值和标准差。分析二维放射摄影、DTS和CBCT之间的定位差异。

结果

收集了10例患者65个治疗分次的图像数据集。患者的系统定位变化在一维方向上<0.10 cm且<1.0度。随机变化在平移方向上为0.27 - 0.34 cm，在旋转方向上为0.93度 - 1.99度。平均矢量等中心变化为0.48 cm。在冠状面或矢状面方向上扫描角度为40度和20度的DTS在患者定位方面产生相同结果。DTS的性能与CBCT相当，定位差异<0.1 cm和<0.5度。二维放射摄影和DTS在垂直/纵向和横向方向上的定位差异分别约为0.1 cm和0.2 cm。