乳腺癌改良根治术后图像引导放疗图像配准的影响因素

目的:探讨乳腺癌改良根治术后图像引导放疗不同体位固定图像配准的效果.方法:乳腺癌改良根治术后20例患者采用泡沫负压真空垫行治疗体位固定(体模A组),20例患者采用热塑连体网罩行治疗体位固定(连体网罩C组),进行CBCT釆集图像并与计划CT图像配准,分别记录左右方向(X)、头脚方向(Y)、前后方向(Z)的平移误差及旋转误差值,计算其均值、标准差,进行统计学处理.结果:本研究A、C组釆集图像各100张,匹配结果平移误差在X、Y、Z方向,A组分别为(2.17±1.51) mm、(1.33±1.15) mm、(2.18±1.53) mm;C组分别为(1.35±1.28) mm、(1.25±1.13) mm、(1.46±1.33) mm.旋转误差在X、Y、Z方向,A组分别为(3.94±1.25)°、(2.31±1.32)°、(3.82±1.83)°;C组分别为(2.92±1.73)°、(2.43±1.12)°、(2.35±1.23)°.其中≤3°概率: A组分别为83.2%、82.6%、84.5%,最大值分别为5.1°、3.2°、4.8°;C组分别为87.3%、88.3%、85.8%,最大值分别为3.3°、3.1°、3.5°.两套体位固定装置在X、Y、Z三方向的平移误差经配对样本检验在Y方向P>0.05,在X、Z方向P<0.05,C组明显优于A组.两套装置测量差值有负相关关系.结论:乳腺癌改良根治术后放疗采用连体网罩行治疗体位固定,重复性好.C组能降低X、Z方向上的误差,其放疗靶区中心的平移误差中差异有统计学意义,因此建议乳腺癌改良根治术后放疗体位固定时优选连体网罩固定装置,提高图像引导放射治疗精准体位的要求,提高临床治疗效果.

Factors of influencing the image registration of image guided radiotherapy after modified radical mastectomy for breast cancer

Objective:To investigate the effects of different fixed positions image registration on the position correction for breast cancer patients after modified radical mastectomy underwent image guided radiation therapy (IGRT).Methods:20 patients with breast cancer after modified radical mastectomy were treated with foam vacuum mat fixed position (group A),and the other 20 patients were treated with a hot plastic integrated net cover fixed position (group C).Through registration of CBCT image with the planning CT image,translational set-up errors and rotation errors were determined along left-right (X),super-inferior (Y),and anterior-posterior (Z) direction.Statistical analysis was performed to the average deviation and standard deviation of the set-up errors determined.Results:In this study,100 images were collected from each group,and the registration results showed the translation error was in X,Y,Z direction,with (2.17±1.51) mm,(1.33±1.15) mm,(2.18±1.53) mm in group A,and (1.35±1.28) mm,(1.25±1.13) mm,(1.46±1.33) mm in group C.In the rotation error with X,Y,Z direction,group A were respectively (3.94±1.25)°,(2.31±1.32)°,(3.82±1.83)°,and group C respectively (2.92±1.73)°,(2.43±1.12)°,(2.35±1.23)°.In less than or equal to 3° probability,group A were 83.2%,82.6%,84.5%,maximum values respectively 5.1°,3.2°,4.8°,and group C were 87.3%,88.3%,85.8%,maximum values respectively 3.3°,3.1°,3.5°.Direction translation error for two sets of position fixing device in the X,Y,Z was found by paired sample test,in the Y direction P>0.05,in the X,Z direction P<0.05,and group C was better than group A.Two sets of device measurement difference had a negative correlation.Conclusion:The fixed position of radiotherapy with fixed mesh after breast cancer modified radical mastectomy has good repeatability.C group can reduce X,Z direction error,and the difference of translational error of radiotherapy target center was statistically significant.Therefore,it is suggested breast modified radical postoperative radiotherapy immobilization is preferably connected network cover fixing device,which could improve the image guided radiation therapy precision posture requirements and clinical therapeutic effect.