ExacTrac X射线图像引导系统在儿童颅内神经肿瘤立体定向放射外科治疗中的应用研究

Application of ExacTrac X-ray image guided system in SRS treatment for children with intracranial neural tumors

目的:研究ExacTrac X射线图像引导系统在3~14岁儿童颅内神经肿瘤无框架立体定向放射外科(SRS)治疗中的摆位精度及其影响因素。方法:选取医院收治的37例3~14岁颅内神经肿瘤患儿,经红外线标记自动摆位后,采用ExacTrac X射线图像引导系统拍摄双侧斜位交叉射野照片,并与计划系统数字重建的射野图像进行比对配准修正后,得到左右方向(X轴方向)、头脚方向(Y轴方向)及腹背方向(Z轴方向)的平移精度误差及相应的3个旋转精度误差的平均值和标准差,并对其数据进行扩展分析。结果:37例3~14岁患儿经ExacTrac X射线图像引导系统配合六维床摆位修正后测得X轴、Y轴和Z轴3个方向的平移精度误差和3个旋转精度误差,平移精度误差分别为0.26±0.13)mm、(0.17±0.13)mm和(0.15±0.11)mm,旋转精度分别为(0.21±0.15)°、(0.18±0.15)°和(0.18±0.14)°,平移精度误差均<0.5 mm,旋转精度误差均<0.5°,可满足SRS治疗要求。结论:Exac TracX射线图像引导系统配合六维床摆位修正后可明显提高3~14岁颅内神经肿瘤患儿SRS治疗精度,是一种值得应用在儿童颅内神经肿瘤诊疗中的技术。

Objective:To investigate the setup precision of ExacTrac X-ray image guided system in the treatment of frameless stereotactic radiosurgery(SRS)of intracranial neural tumors of children aged 3-14 years,and to discuss its influence factors.Methods:Thirty-seven children aged 3-14 years with intracranial neural tumors who admitted to hospital were enrolled in this study.After they underwent automatic setup with infrared markers,ExacTrac X-ray image guided system was applied to obtain the image of bilaterally oblique intersection field.After these images were compared,rectified and amended with images of radiation field which were digitally reconstructed by planning system,the precision errors of translation at left and right direction(X-axis direction),head and foot direction(Y-axis direction)and abdomen and back direction(Z-axis direction)were obtained.And then these data were expanded and analyzed.Results:After the setups of 37 children aged 3-14 years with intracranial neural tumors were rectified by Exac Trac X-ray image guided system with six-dimensional couch,the precision errors of the translation at three directions(X-axis,Y-axis and Z-axis)and the errors of 3 running precisions were measured.The precision errors of translation were(0.26±0.13)mm,(0.17±0.13)mm and(0.15±0.11)mm,respectively.And the running precisions were(0.21±0.15)°,(0.18±0.15)°,(0.18±0.14)°,respectively.All of precision errors of translation were less than 0.5 mm,and the precision errors of running were less than 0.5°.And these errors could meet the requirement of SRS treatment.Conclusion:After the setup is rectified by using ExacTrac X-ray image guided system with six-dimensional couch can remarkably improve the precision of SRS treatment for children aged 314 years with intracranial neural tumor.ExacTrac X-ray image guided system is one kind of worthy technique that is applied in intracranial neural tumor of children.