Fraxion系统与热塑膜固定在脑恶性肿瘤放疗中的摆位误差比较

Comparison of Setup Errors Between Fraixon System and Thermoplastic Film in Radiotherapy Immobilization for Brain Malignancy

目的评估Fraxion系统与热塑膜在脑恶性肿瘤放疗体位固定中的摆位准确性。方法选取2018年1月至2022年9月在我院肿瘤内科接受头部放疗固定的脑恶性肿瘤患者92例(采用Fraxion系统32例,热塑膜60例)为研究对象。将锥形束容积断层成像技术图像与计划电子计算机断层扫描图像匹配后获得线性摆位误差、3D矢量位移;根据外扩边界(Margin of Planning Target Volume,MPTV)公式计算出计划靶区MPTV,比较Fraxion系统组和热塑膜组的摆位准确性。结果Fraxion系统组和热塑膜组的摆位误差在左右方向(X轴)分别为(0.79±0.45)mm和(1.60±1.00)mm,在头脚方向(Y轴)分别为(0.82±0.46)mm和(1.77±1.07)mm,在前后方向(Z轴)分别为(0.62±0.37)mm和(1.88±1.05)mm;3D矢量位移分别为(1.42±0.45)mm和(3.13±1.62)mm。Fraxion系统组的线性摆位误差、3D矢量位移均小于热塑膜组,差异具有统计学意义(P<0.001)。Fraxion系统组和热塑膜组在X轴、Y轴、Z轴方向的MPTV分别为0.64、0.66、0.52 mm和1.08、1.12、2.64 mm。结论Fraxion系统在脑恶性肿瘤放疗定位中摆位准确性优于热塑膜固定,可精准定位靶区。

Objective To evaluate the positioning accuracy of Fraxion system and thermoplastic film in radiotherapy immobilization for brain malignancies.Methods A total of 92 patients with brain malignancies(32 patients with Fraxion system and 60 patients with thermoplastic film)who received head radiotherapy fixation in the Department of Oncology of our hospital from January 2018 to September 2022 were selected.The linear setting error and 3D vector displacement were obtained by matching the cone beam volume tomography image with the planned computerized tomography image.According to the formula of margin of planning target volume(MPTV),the MPTV of the planned target area was calculated,and the positioning accuracy of Fraxion system group and thermoplastic film group was compared.Results The setup errors of the Fraxion system group and the thermoplastic film group were(0.79±0.45)mm and(1.60±1.00)mm in the left-right directions(X axis),(0.82±0.46)mm and(1.77±1.07)mm in the superior�inferior directions(Y axis),and(0.62±0.37)mm and(1.88±1.05)mm in the anterior-post directions(Z axis),respectively.The 3D displacement vectors were(1.42±0.45)mm and(3.13±1.62)mm,respectively.The linear setup errors,3D displacement vectors of the Fraxion system group were smaller than those of the thermoplastic film group,and the difference was statistically significant(P<0.001).The MPTV of the Fraxion system group and thermoplastic film group were 0.64,0.66,0.52 mm and 1.08,1.12,2.64 mm in the X,Y and Z axis,respectively.Conclusion Fraxion system is better than thermoplastic film in the positioning accuracy for radiotherapy of brain malignancy,and can accurately locate the target area.