六点标记法提高盆腔肿瘤放疗摆位精度

Improving the setup accuracy in radiotherapy for pelvic tumors by six marks location method

目的:验证六点标记法与传统的三点标记法相比可否提高盆腔肿瘤摆位精度。方法:将60例盆腔肿瘤患者随机分为两组:三点标记组采用传统的三点标记法,六点标记组采用新型的六点标记法,每组各3例。治疗前在加速器拍摄射野验证片与计划系统生成的射野视野方向观(Beam's Eye View,BEV)相比较,统计X(左右)、Y(头脚)、Z(腹背)3个方向的摆位误差。结果:六点标记组与三点标记组Z方向两组差异无统计学意义(t=0.53,P>0.05),说明腹背方向六点标记法未能明显减少摆位误差;X、Y方向两组有明显统计学意义(t=3.97,P<0.05;t=3.23,P<0.05),说明左右及头脚方向六点标记法能明显减少摆位误差。结论:使用六点定位法能明显提高盆腔肿瘤患者的放疗摆位精度,且方法简便易行,具有临床推广价值。

Objective To analyze whether six marks location method could improve the setup accuracy of pelvic tumor by comparing the traditional three marks location method with six marks location method. Methods Sixty patients with pelvic tumor were randomly divided into two groups, three marks group and six marks group, each group of 30 cases. The field verification films taken by accelerator before treatment was compared with field Beam＇s eye view （BEV） films generated from the planning system. The setup errors of X, Y, Z three directions were analyzed by statistics. And the X, Y, Z were the representative for left and right, head and feet, back and belly, respectively. Results No significant differences were found between six marks group and three marks group in Z direction （t=-0.53, P〉0.05）, which explained that in Z direction, six marks location method could not reduce setup errors. There were significant differences in X and Y directions （t=3.97, P〈0.05; t=- 3.23, P〈0.05）, which showed that in X and Y directions, six marks location method could significantly reduce setup errors. Conclusion With simple and convenient operation, six marks location method can significantly improve the setup accuracy for patients with pelvic tumor, so the method has the value of clinical practice.