ExacTrac图像引导系统结合六维床在SRS治疗摆位中的可靠性研究

A study on reliability of ExacTrac image-guided system with 6D couch in positioning of SRS treatment

目的:研究ExacTrac图像引导系统结合六维床修正立体定向放射外科(SRS)摆位误差数据的可靠性。方法:选取医院收治的62例实施放射治疗患者,根据治疗方法的不同,将其分为观察组(32例)和对照组(30例)。观察组患者应用ExacTrac图像引导系统结合六维床摆位,并利用电子射野影像装置(EPID)拍摄0°和90°验证片后行SRS治疗;对照组患者直接应用EPID系统拍片验证后行常规调强放射治疗(IMRT)。分析比较两组患者的摆位误差在左右方向(x)、头脚方向(y)和腹背方向(z)3个方向的差异性。结果:观察组采用ExacTrac图像引导系统结合六维床修正摆位误差后得到的EPID系统摆位在x、y和z的3个方向上误差小于对照组直接获取的EPID系统摆位误差,其差异均具有统计学意义(Z=-3.696,Z=-3.810,Z=-3.436;P<0.05);观察组在x、y和z的3个方向的平移误差分别为(0.12±0.10)mm、(0.14±0.14)mm和(0.09±0.07)mm,旋转误差分别为(0.09±0.08)°、(0.10±0.08)°和(0.18±0.14)°。结论:ExacTrac图像引导系统结合六维床在SRS治疗时所获取的摆位误差数据可靠,且明显提高摆位精度。

Objective: To explore the reliability that ExacTrac image-guided system combined with 6-dimension(6 D) couch to amend setup error of stereotactic radiotherapy surgery(SRS). Methods: 62 patients underwent radiotherapy were chosen and were divided into observation group(32 cases) and control group(30 cases) according to different treatment method. Patients of observation group applied ExacTrac image-guided system with 6 D couch to implement position and they underwent SRS treatment after electronic portal imaging device(EPID) was used to take verification photos at 0° and 90°. And patients of control group underwent routine intensity modulated radiation therapy(IMRT) after EPID system was directly used to take verification photos. The differences of setup errors of two groups at directions of left and right(x), directions of head and food(y) and directions of abdomen and back(z) were analyzed and compared. Results: The setup errors of EPID system with ExacTrac image-guided system and 6 D couch of observation group at x-, y-and z-directions significantly less than those that directly obtained from EPID system of control group(Z=-3.696, Z=-3.810, Z=-3.436, P<0.05), respectively. The translation errors of observation group at x-, y-, z-direction were(0.12±0.10) mm,(0.14±0.14) mm,(0.09±0.07) mm, respectively, and the rotation errors of observation group were(0.09±0.08°),(0.10±0.08 °) and(0.18±0.14 °), respectively. Conclusion: In SRS treatment, the setup error data that obtained from ExacTrac image-guided system with 6 D couch are reliable, and it obviously can increase the positioning accuracy.