应用锥形束CT对157例儿童腹部肿瘤摆位误差及靶区外放边界的分析

Application of CBCT to analyze the placement error of abdominal tumors in 157 children and the boundary of the target area

目的应用锥形束CT对儿童腹部肿瘤摆位误差及靶区外放边界进行分析研究,以提高放射治疗精度,提高疗效。方法选取北京协和医院放疗科2018年3月至2019年2月157例1~14岁腹部肿瘤儿童患者为研究对象,收集患儿整个治疗期间168组锥形束CT(CBCT)图像数据进行分析,计算出升降方向(VRT)、进出方向(LNG)、左右方向(LAT)3个方向上的误差。利用外放边界公式=2.5∑+0.7δ计算出计划靶区(PTV)外放边界。结果通过SPSS21.0统计学分析得出3个方向的摆位误差分别为:VRT(-0.05±2.32)mm,LNG(0.11±2.67)mm,LAT(0.17±2.43)mm;计算出PTV外放边界为:VRT=9.1mm,LNG=10.2mm,LAT=9.4mm。结论儿童腹部肿瘤放疗靶区外放范围VRT=9.1mm,LNG=10.2mm,LAT=9.4mm为放射治疗最佳精度,为提高疗效提供了依据。

Objective To analyze the placement error of the abdominal tumor in children and the boundary of the target area by CBCT,in order to improve the accuracy of radiation therapy and improve the curative effect.Methods A total of 157 children aged 1-14 years old with abdominal tumors from March 2018 to February 2019 were enrolled in the Department of Radiotherapy of Peking Union Medical College Hospital.The data of 168 groups of CBCT(cone beam computed tomography)were collected during the whole treatment period,and to calculate the error in three directions:vertical(VRT),longitudinal(LNG),and lateral(LAT).The planning target volume(PTV)external boundary was calculated using the external boundary formula=2.5∑+0.7δ.Results The statistical analysis of SPSS 21.0 showed that the placement errors in three directions were:VRT(-0.05±2.32)mm,LNG(0.11±2.67)mm,LAT(0.17±2.43)mm;calculate the PTV external boundary:VRT=9.1 mm,LNG=10.2 mm,and LAT=9.4 mm.Conclusions The radiotherapy target area of children s abdominal tumors is VRT=9.1 mm,LNG=10.2 mm,and LAT=9.4 mm is the best precision for radiotherapy,which provides a basis for improving the curative effect.