四种不同配准方式对食管癌IGRT摆位误差的影响

目的:研究四种不同配准方法对食管癌图像引导放射治疗（IGRT）摆位误差的影响。方法:应用瑞典医科达Synergy直线加速器治疗食管癌患者100例，每位患者治疗前用锥形束CT（CBCT）扫描。将获得的CBCT图像与计划CT图像配准，分析左右（X）、头脚(Y)、上下(Z)方向上的平移误差，比较自动灰度配准、自动灰度+手动配准、自动骨性配准、自动骨性+手动配准四种配准间的差异。结果:100例食管癌患者共进行400次配准。自动灰度配准、自动灰度+手动配准、自动骨性配准、自动骨性+手动配准在左右(X)方向的平移误差分别为（2.70±2.20）mm、（3.04±2.36）mm、（2.76±2.24）mm、（3.04±2.45）mm，在头脚（Y）方向的平移误差分别为（2.82±2.15）mm、(2.95±2.31) mm、（2.74±1.78）mm、（2.66±1.82）mm，在上下（Z）方向的平移误差分别为（2.42±1.91）mm、（2.49±2.02）mm、（3.07±2.16）mm、（2.67±2.02）mm。其中自动灰度与自动灰度+手动配准在X、Z方向差异有统计学意义(P<0.05)，自动骨性与自动骨性+手动配准在X方向差异有统计学意义（P<0.05)，自动灰度与自动骨性、自动灰度+手动配准与自动骨性+手动配准在X、Y、Z方向上均差异无统计学意义(P>0.05)。结论:对于食管癌肿瘤的图像配准，加上手动配准是有必要的，骨性配准+手动配准精度和稳定性效果更好。

Comparative study on set -up errors with four different image registrations for esophageal tumor in image guided radiation therapy

Objective:To investigate four different image registrations for esophageal tumor in image guided radia-tion therapy.Methods:All 100 esophageal tumor patients were treated by the Elekta Synergy IGRT system,compare the difference between CBCT images and planning CT images in Automatic grey -value registration,Automatic grey -value +Manual registration,Automatic bone registration,Automatic bone +Manual registration.Results:Total of 400 CBCT images were registrated for 100 esophageal tumor patients.The set -up errors on X -axis ofAutomatic grey -val-ue registration,Automatic grey -value +Manual registration,Automatic bone registration,Automatic bone +Manual registration were (2.70 ±2.20)mm,(3.04 ±2.36)mm,(2.76 ±2.24)mm,(3.04 ±2.45)mm respectively.The set -up errors on Y -axis were (2.82 ±2.15)mm,(2.95 ±2.31)mm,(2.74 ±1.78)mm,(2.66 ±1.82)mm re-spectively.The set -up errors on Z -axis were (2.42 ±1.91)mm,(2.49 ±2.02)mm,(3.07 ±2.16)mm,(2.67 ± 2.02)mm respectively.There was significant difference between Automatic grey -value registration and Automatic grey -value +Manual registration in X -axis,Z -axis(P <0.05),there was significant difference between Automatic bone registration and Automatic bone +Manual registration in X -axis(P <0.05),there was no significant difference between Automatic grey -value registration and Automatic bone registration,Automatic grey -value +Manual regis-tration and Automatic bone +Manual registration in X,Y,Z -axis(P >0.05).Conclusion:It is suggested that Auto-matic bone +Manual registration may be the best solution to reduce the set -up errors for esophageal tumor in IGRT.