肝癌VMAT放疗中两种体位固定方式摆位误差分析

Analysis of Setup Errors of Two Position Fixing Manners in VMAT Radiotherapy for Liver Cancer

目的比较肝癌在容积旋转调强放疗中两种体位固定方式的摆位误差。方法回顾性分析2012年12月至2015年12月在武装警察部队后勤学院附属医院接受过治疗的40例肝癌患者的临床资料,其中热塑膜加真空负压袋体位固定(A组)20例,热塑膜体位固定(B组)20例。记录两组患者首次治疗及治疗期间每周(仅记录前4周数据)的锥形束CT摆位误差数据。对两种方法 200组摆位误差数据进行分析。结果 A组在上下(Vrt)方向从第3周开始误差变大,到第4周与B组相比误差变大较显著。两组首次治疗左右(Lat)、Vrt、头脚(Lng)方向摆位误差比较差异无统计学意义(P>0.05);第4周治疗Lat、Lng方向摆位误差比较差异无统计学意义(P>0.05),A组Vrt方向摆位误差大于B组[(2.12±1.48)mm比(1.44±1.53)mm](P<0.01)。结论对于肝癌患者,两种体位固定方式均能满足临床要求,针对具体病例可个性化选择适合的体位固定方式。

Objective To explore the setup error of two different position fixing manners in the treatment of volumetric modulated arc therapy（VMAT） for liver cancer patients. Methods Totally 40 liver cancer patients undergoing radiation treatment with VMAT technique were included in the study, including 20 cases of thermoplastie fixation mask ＋ vacuum fixa tion cushion（ group A ） and 20 cases of thermoplastie fixation mask （group B）. A weekly setup error data by cone-beam computed tomography（CBCT） was recorded during the first treatment and treatment period（for the first 4 weeks）. Analysis on the 200 sets of setup error data of the two methods was done. Results In group A, the error increased from week three in vertical（Vrt） direction,and the error difference from that in group B at week four was more significant. There was no signifi- cant difference between the two groups in the position error of latitude （Lat）, Vrt, longitude （Lng） at first treatment between the two groups（P 〉 0. 05 ）. There was no significant difference in the alignment error of Lat and Lng direction at the fourth week （ P 〉 0.05 ）. The alignment error of Vrt in group A was greater than that in group B [ （2.12 ± 1.48 ） mm vs （ 1.44 ±1.53 ） mm] （P 〈 0.01 ）. Conclusion The comparative analysis showed that both position fixing manners can meet the elini-eal requirements ,and the appropriate way of position fixation should be chosen according to specific situation case-by-case.