头部立体放射治疗中两种固定方式的精度比较

目的:比较双面网和单面网两种固定方式对头部立体定向放射治疗病例摆位精度的影响。方法:选取40例头部立体定向放射治疗患者，分为对照组（传统单面网固定）和试验组（新型双面网固定）。获取患者治疗前锥形束CT图像，记录按照骨性标志配准误差并进行统计学分析。结果:两组摆位误差在左右（Lat）、进出（Lng）、升降（Vrt）、俯仰（Pitch）、翻转（Roll）、旋转（Rtn）各方向平均数±标准差表示为:对照组（0.26±0.15） cm、（0.13±0.10） cm、（0.19±0.13） cm、（1.40±0.75）°、（1.31±0.65）°、（1.00±0.60）°；试验组（0.07±0.08） cm、（0.14±0.13） cm、（0.09±0.09） cm、（0.73±0.62）°、（0.72±0.58）°、（0.66±0.52）°。两组数据使用曼恩-惠特尼U检验，Lat、Vrt、Pitch、Roll、Rtn方向有统计学差异（P<0.05），Lng方向无统计学差异（P>0.05）。结论:相对于单面网，双面网固定方式在头部立体定向放射治疗中减小了患者的摆位误差，提高了治疗精度，可使患者获益。【关键词】立体定向放射治疗；摆位误差；单面网；双面网

Comparison of setup accuracy between two immobilization techniques in stereotactic body radiotherapy for head cancer

Objective To compare the differences of setup accuracy in stereotactic body radiotherapy for head cancer using two different immobilization techniques,namely single shell positioning system(SSPS)and double shell positioning system(DSPS).Methods Forty patients treated with stereotactic body radiotherapy for head cancer were diveided into two groups and then immobilized with SSPS(control group)and DSPS(experimental group).After that the pre-treatment cone beam CT images were obtained,the setup errors were acquired through image registration based on bony landmarks for statistical analysis.Results The setup errors(Mean±SD)in lateral(Lat),longitudinal(Lng),vertical(Vrt),Pitch,Roll and rotation(Rtn)directions in control group were(0.26±0.15)cm,(0.13±0.10)cm,(0.19±0.13)cm,(1.40±0.75)°,(1.31±0.65)°and(1.00±0.60)°,respectively,and those in experimental group were(0.07±0.08)cm,(0.14±0.13)cm,(0.09±0.09)cm,(0.73±0.62)°,(0.72±0.58)°and(0.66±0.52)°,respectively.The results of Mann-Whitney U test showed that there were statistical differences between two gourps in Lat,Vrt,Pitch,Roll and Rtn directions(P<0.05),but not in Lng direction(P>0.05).Conclusion Compared with SSPS,DSPS reduces the setup errors in stereotactic body radiotherapy for head caner and improves treatment accuracy,thereby bringing benefits to patients.