锥形束CT引导摆位与光学引导摆位比较  

Comparison of cone beam CT guidance system and optical positioning system

作　　者：王健[1] 李文浩[2] 葛云[2] 

机构地区：[1]常熟市第二人民医院医学工程部,江苏常熟215500 [2]南京大学电子科学与工程学院,江苏南京210046

出　　处：《中国医学物理学杂志》2016年第1期106-108,共3页Chinese Journal of Medical Physics

摘　　要：目的:比较放射治疗中使用的锥形束CT(CBCT)引导定位技术和光学引导定位技术(OPS)的摆位误差。方法:在Varian治疗系统下对模体进行摆位对比试验获得误差数据。首先,将一个方形膜体作为虚拟的病人,通过CBCT引导定位系统摆位完成,然后,用游标卡尺在坐标纸上测量左-右方向和前-后方向摆位误差。调整治疗床高度使得源皮距为100cm,并记录床的高度变化值,该值即为上-下方向上的摆位误差。然后,使用同样方法记录下OPS显示的摆位误差。结果:CBCT的平均摆位误差在左-右、上-下、前-后方向分别为0.42、0.50、0.66 mm,其均方差在左-右、上-下、前-后方向分别为0.24、0.00、0.52 mm。OPS的平均摆位误差在左-右、上-下、前-后方向分别为0.28、0.40、0.30 mm,其均方差在左-右、上-下、前-后方向分别为0.08、0.10、0.07 mm。结论:从定位精度和稳定性方面来看,OPS引导定位技术优于CBCT引导定位技术。Objective To compare the set-up errors of cone beam CT （CBCT） guidance system and optical positioning system （OPS） applied in radiotherapy. Methods Set-up data were collected by the comparative experiment for a phantom in Varian treatment system. The square phantom taken as a virtual patient was positioned by using CBCT guidance system. The set-up errors in left-to-right （LR） and anterior-to-posterior （AP） directions on the coordinate paper were measured by a vernier caliper. The treatment couch height was adjusted to ensure the source-to-surface distance （SSD） of 100 cm. The height changes which were set-up errors in inferior-to-superior （IS） direction were recorded. And the set-up errors of OPS were obtained by using the same method. Results The average set-up errors of CBCT guidance system were respectively 0.42 mm, 0.50 mm and 0.66 mm in LR, IS and AP directions; the root-mean-squares （RMS） were respectively 0.24 mm, 0.00 mm and 0.52 mm in LR, IS and AP directions. The average set-up errors of OPS were respectively 0.28 mm, 0.40 mm and 0.30 mm in LR, IS and AP directions; RMS were respectively 0.08 mm, 0.10 mm and 0.07 mm in LR, IS and AP directions. Conclusion Compared with CBCT guidance system, OPS has a better position accuracy and a better position stability.

关 键 词：锥形束CT 引导定位技术 光学引导定位技术 摆位误差 定位精度 

分 类 号：R811.1[医药卫生—放射医学]