放疗中床高变化与摆位误差的相关性研究

Study the Correlation of the Height Change of Treatment Bed and Setup Error on Radiation Therapy

目的探讨放疗中床高变化对摆位误差的影响。方法随机选取100例胸腹部肿瘤患者,应用CBCT对其前3次治疗摆位误差进行测量,测量值分别标记为Ⅰ、Ⅱ、Ⅲ组。Ⅰ组目的是寻找肿瘤中心,确定治疗床高度H1;Ⅱ组是尚未对治疗床高度进行限制时的摆位误差;Ⅲ组是对治疗床高度进行限制后的摆位误差。结果Ⅱ组测量的摆位误差在X轴为(2.48±1.18)mm、Y轴为(2.33±1.09)mm、Z轴为(2.46±1.01)mm。Ⅲ组测量的摆位误差在X轴为(2.35±1.01)mm、Y轴为(2.04±0.90)mm、Z轴为(2.09±0.92)mm。对Ⅱ、Ⅲ两组摆位误差进行统计学处理,结果显示:两组摆位误差X轴比较无统计学意义(P>0.05),Y轴比较有统计学意义(P<0.05),Z轴比较有统计学意义(P<0.05)。结论在放疗摆位中,对治疗床高限制后能减少摆位误差,将治疗床高作为放疗摆位的一个参考依据,有利于放疗质量保证(QA)的实施。

Objective To investigate the influence of treatment of bed height change to setup error on radiation therapy.Methods 100 cases of chest and abdominal cancer patients were randomly selected.CBCT was used to measure setup error the first three times,and then divided measurements into three groups（that is Ⅰ、Ⅱ and Ⅲ）.The purpose of groupⅠis to find the cancer center and ascertain the height of treatment bed（H1）;measurements of group Ⅱ is the setup error before limiting the height of treatment bed;measurements of group Ⅲ is the setup error after limiting theheight of treatment bed.Results Setup error on the X axis is（2.48±1.18）mm,Y axis is（2.33 ±1.09）mm,Z axis is（2.46±1.01）mm of group Ⅱ,and X、Y and Z axis are（2.35 ±1.01）mm,（2.04±0.90） mm and（2.09±0.92）mm of groupⅢ.Statistical method was used to calculate the data,univariate analysis showed it had no statistical difference on X axis（P0.05） and significant statistical difference on Y axis（P0.05） and Z axis（P0.05）.Conclusion In the process of beam positioning on radiation therapy,it can reduce setup error by limiting the height of treatment bed,and it will be conducive to implement radiotherapy quality assurance（QA） by taking the height of treatment bed as the basis of beam positioning on radiation therapy.