摘要
目的对比分析真空袋和orfit架两种体位固定方式在盆腔妇科肿瘤放射治疗中的体位重复性,为临床PTV外扩和选取合适固定方式提供依据。方法行盆腔放疗的妇科肿瘤患者共388例,其中真空袋固定患者257例,CBCT扫描次数4768次;Orfit架固定患者131例,CBCT扫描次数2955次。收集两组患者在三维方向上的摆位误差数据,分别为左右(X轴)、头脚(Y轴)、升降(Z轴)。根据靶区外扩公式MPTV=2.5∑+0.7σ计算两种固定方式在三维方向上的靶区外扩边界。结果真空袋组和orfit架组的摆位误差分别为X轴:(-0.70±3.48)mm和(-0.76±3.49)mm,P=0.446;Y轴:(0.53±3.75)mm和(-2.61±4.83)mm,P=0.000;Z轴:(0.28±3.27)mm和(0.04±3.23)mm,P=0.002。两种固定方式在X、Y、Z 3个方向上计算的靶区外扩分别为(7.4,7.4,7.3)mm和(7.2,9.5,7.1)mm。结论真空袋组固定效果在Y轴方向上比orfit架组更好,并可在一定程度上减少靶区外扩。在X、Z轴两个方向,两种固定方式的误差绝对值无太明显区别。临床实践中应根据实际情况和患者可接受的体位选择合适的体位固定方式,并相应进行合理的PTV外扩,进一步提高放射治疗的精确性。
Objective To compare fixation stability between vacuum bag and Orfit rack in gynecologic maglignancies radiotherapy,and provide basis for the PTV margin and appropriate fixation ways.Methods 257 patients were fixed with vacuum bag along with 4768 CBCT scans and 131 patients were fixed with Orfit rack along with 2955 CBCT scans.Translational setup errors were collected after CBCT registration for 2 groups,X(Left-Right),Y(Superior-Inferior),Z(Anterior-Posterior).Formula margin of planning target volume:MPTV=2.5Σ+0.7σwas also applied to calculate the margin of the target between two fixation ways.Results The setup errors between vacuum bag and Orfit rack were:X(-0.70±3.48)mm and(-0.76±3.49)mm,P=0.446;Y(0.53±3.75)mm and(-2.61±4.83)mm,P=0.000;Z(0.28±3.27)mm and(0.04±3.23)mm,P=0.002.The margin of the target in X,Y,Z directions between 2 fixation ways were(7.4,7.4,7.3)mm and(7.2,9.5,7.1)mm,respectively.Conclusion Vacuum bag had better fixation performance than Orfit rack in Y direction and the target margin could be reduced to some extent.There was no significant differences in the absolute value of setup errors between two fixation ways in X,Z direction.Fixation ways should be chosen according to real conditions and patients'acceptance in clinical pratice as well as adapting appropriate PTV margin to improve the accuracy of radiotherapy.
作者
刘明治
许森奎
刘镖水
LIU Mingzhi;XU Senkui;LIU Biaoshui(Sun Yat-sen University Cancer Center,Guangzhou,510060)
出处
《实用癌症杂志》
2023年第6期1018-1021,共4页
The Practical Journal of Cancer
关键词
妇科肿瘤
真空袋
orfit架
体位固定
放射治疗
Gynecologic maglignancies
Vacuum bag
Orfit rack
Immobilization
Radiotherapy
