ExacTrac X线图像引导系统对骨转移癌大分割放疗摆位误差的纠正分析

The correction and analysis of setup errors in the hyperfractionated radiotherapy of bone metastases with ExacTrac X-ray image-guidance system

目的探讨ExacTrac X线图像引导系统在骨转移癌大分割放疗中的应用可行性。方法收集2016年12月至2018年6月接受大分割放疗的56例骨转移癌患者,每次治疗前采用ExacTrac系统进行图像引导,得到左右、头脚、腹背3个平移方向以及左右、头脚、腹背3个旋转方向的摆位误差,采用6D治疗床进行纠正,得到ExacTrac系统纠正后的患者体位摆位误差,采用Wilcoxon检验分析比较纠正前后摆位误差值。结果56例骨转移癌患者获得纠正前后各448组6D误差值。纠正前后,左右、头脚、腹背方向平移摆位误差分别为(2.263±1.9652)mm和(0.428±0.3894)mm,(3.899±2.8935)mm和(0.428±0.3563)mm,(1.883±1.8522)mm和(0.459±0.4865)mm,左右、头脚、腹背方向旋转摆位误差分别为(0.943±0.8266)°和(0.264±0.2186)°,(0.798±0.8750)°和(0.384±0.4891)°,(1.082±1.0431)°和(0.241±0.2104)°,各方向纠正前后摆位误差的差异均有统计学意义(P<0.05)。结论ExacTrac图像引导系统可以减少骨转移癌大分割放疗的摆位误差,值得临床推广应用。

Objective To investigate the application feasibility of ExacTrac X-ray image-guidance system in hyperfractionated radiotherapy of bone metastases.Methods From December 2016 to June 2018,a total of 56 bone metastases patients who were treated with hyperfractionated radiotherapy were enrolled.ExacTrac X-ray image-guidance system was used before treatment and then the Lat,Long,Vert direction of 3 translation and the Pitch,Roll,Yaw direction of 3 rotation(6D error)of the former were gained.The 6D treatment bed was used for correction.Finally,ExacTrac 6D image-guidance system were utilized to validate the 6D errors of the patients'position.Wilcoxon analysis was used to compare the positioning errors before and after correction.Results Four hundred and forty-eight 6D errors before and after correction were found in 56 paitents with bone metastases.Setup errors before and after correction were(2.263±1.9652)mm vs.(0.428±0.3894)mm in Lat direction,(3.899±2.8935)mm vs.(0.428±0.3563)mm in Long direction,(1.883±1.8522)mm vs.(0.459±0.4865)mm in Vert direction,(0.943±0.8266)°vs.(0.264±0.2186)°in Pitch direction,(0.798±0.8750)°vs.(0.384±0.4891)°in Roll direction,and(1.082±1.0431)°vs.(0.241±0.2104)°in Yaw direction.The differences in all directions before and after correction were statistically significant(P<0.05).Conclusion Application of ExacTrac Xray image-guidance system in hyperfractionated radiotherapy of bone metastases treatment is feasible.In addition,it can obviously decrease the setup errors during hyperfractionated radiotherapy.