乳腺癌术后全乳房放疗皮肤表面定位摆位误差相关研究

Correlative study on positioning error of skin surface positioning after breast cancer surgery

目的通过图像分析探究乳腺癌术后全乳房放疗中的皮肤定位摆位误差。方法选择2019年1-8月在浙江省肿瘤医院行辅助放疗的乳腺癌保乳手术术后患者80例。治疗计划中为每位患者创建CT定位图像,放疗过程中在对患者摆位完成后扫描获得锥形束CT(CBCT)验证片,通过图像处理软件将CT定位图像和CBCT验证片叠加至每位患者皮肤表面位置。测量乳头-肺(X轴)方向和颅尾(Y轴)方向的等中心偏差以及叠加图像X、Y轴旋转角度的偏差。结果在80例乳腺癌患者中,X、Y轴和旋转角度的系统误差(μ)分别为(0.01±0.01)mm、(-1.35±0.14)mm和(0.06±0.01)°;X、Y轴和旋转角度之间的系统误差(Σ)分别为(1.76±0.72)mm、(1.49±0.58)mm和(0.90±0.12)°;X、Y轴和旋转角度的随机误差分别为(1.34±0.96)mm、(1.93±1.02)mm和(1.0±0.2)°;在整体和左右侧患者中总矢量误差分别为(3.02±1.26)、(2.88±1.03)和(3.25±1.38)mm,均不具有临床意义。结论乳腺癌保乳手术后常规乳房放射治疗过程中依据皮肤表面位置并且结合使用图像处理软件可获得足够小的摆位误差。

Objective To investigate the skin positioning error in total breast radiotherapy after breast cancer surgery through image analysis.Methods The study period was from January 2019 to June 2019.A total of 80 patients who received breast-conserving breast cancer surgery and adjuvant radiotherapy during this period in Zhejiang Cancer Hospital were selected.The CT positioning image for each patient in the treatment plan was created and the relevant cone beam computed tomography verification film after the patient positioning setting was obtained during radiotherapy,and the positioning map and the verification film to each patient through image processing software skin surface location were overlapped.The isocenter deviation of the nipple-lung(X)and cranial tail(Y)directions and the deviation of the X and Y axis rotation angle of the superimposed image were measured.Results In the 80 patients,the system error(μ,Σ)and random error(σ)were calculated based on the X-axis and Y-axis deviation and the rotation angle deviation.Theμvalue of X-axis,Y-axis and rotation angle were(0.01±0.01)mm,(-1.35±0.14)mm and(0.06±0.01)°.TheΣvalue of X-axis,Y-axis and rotation angle were(1.76±0.72)mm,(1.49±0.58)mm and(0.90±0.12)°.Theσvalue of X-axis,Y-axis and rotation angle were(1.34±0.96)mm,(1.93±1.02)mm and(1.0±0.2)°.The average value of the total vector error in the left and right patients were(3.02±1.26),(2.88±1.03)and(3.25±1.38)mm,which had no clinical significance.Conclusions In the routine breast radiotherapy after breast-conserving surgery,the smallest position error of the skin can be obtained by using the skin surface position combined with image processing software.