Catalyst HD光学体表引导发泡胶固定乳腺癌调强放疗摆位精度的研究

Accuracy of immobilization with polyurethane in breast cancer radiotherapy fixed on Catalyst HD optical surface imaging

目的探讨光学体表成像在发泡胶固定的保乳调强放疗中的辅助摆位功能及其观察区域对摆位精度的影响。方法选择2020年5月至2021年7月在中山大学肿瘤防治中心接受调强放射治疗的乳腺癌患者34例。每次治疗前按照体表标记线摆位后,利用光学体表监测系统(C⁃RAD Catalyst HD)辅助校正摆位,最后使用锥形束CT(Cone Beam CT,CBCT)进行体位验证。按照光学体表监测感兴趣区域(region of interest,ROI)分单患侧ROI与双侧ROI,记录按标记线摆位后的治疗床床值、Catalyst HD校正后的治疗床床值及CBCT验证后的体位误差数据。将按体表标记线摆位误差与Catalyst HD校正摆位误差、单患侧ROI摆位误差与双侧ROI摆位误差进行t检验分析。结果体表标记线摆位与光学体表辅助摆位在左右、头脚、腹背方向的摆位误差取绝对值后分别为(2.21±2.14)、(2.46±2.22)、(3.33±2.43)mm和(1.42±0.99)、(1.31±0.86)、(1.38±1.06)mm,t值为(LR:-3.473;SI:-4.895;AP:-3.438),均P<0.05。单患侧ROI和双侧ROI在左右、头脚、腹背方向三维线性误差分别为(1.59±1.23)、(1.41±1.02)、(1.50±0.93)mm和(1.71±1.22)、(1.89±1.29)、(1.31±1.71)mm;三维旋转误差分别为[Rtn:(0.53±0.49)°;Roll:(0.77±0.75)°;Pitch:(0.71±0.68)°]和[Rtn:(0.45±0.49)°;Roll:(0.95±0.75)°;Pitch:(0.71±0.69)°],其AP以及Roll中P<0.05,t值为(AP:0.005;Roll:0.003)。结论Catalyst HD可以提高发泡胶固定乳腺癌保乳术后调强放疗摆位精度,在选择光学体表监测系统监测的感兴趣区域时建议选择双侧ROI。

Objective To investigate the auxiliary positioning function of optical body surface imaging in styrofoam-fixed breast-conserving intensity-modulated radiotherapy and the influence of observation area on the positioning. Methods A total of 34 breast cancer patients who received intensity-modulated radiation therapy in Sun Yat-sen University Cancer Center from May 2020 to July 2021 were selected. The position was set according to the marking line of the body surface,and then corrected by the optical body surface monitoring system(C-RAD Catalyst HD),finally the position was verified by cone beam CT(Cone Beam CT,CBCT). The region of interest(ROI)in C-RAD Catalyst HD was divided into single-affected ROI and bilateral ROI. The treatment bed value after positioning according to the marking line,and Catalyst HD correction were recorded separately,and the set-up errors by CBCT were also recorded. The set-up errors according to the marking line of the body surface with the setup errors of Catalyst HD,the set-up errors of the single-affected side ROI with the set-up errors of the bilateral ROI were analyzed by t test. Results The set-up errors by the marking line of the body surface and C-RAD Catalyst HD in the left and right,head-foot,and abdominal-back directions were(2.21 ± 2.14),(2.46 ± 2.22),(3.33 ±2.43)mm and(1.42 ± 0.99),(1.31 ± 0.86),(1.38 ± 1.06)mm respectively(LR:t =-3.473,SI:t =-4.95,AP:t =-3.438,all P < 0.05). The three-dimensional linear errors of single-affected ROI and bilateral ROI in the leftright,head-foot,and abdominal-back directions were(1.59 ± 1.23),(1.41 ± 1.02),(1.50 ± 0.93)mm and(1.71± 1.22),(1.89 ± 1.29),(1.31 ± 1.71)mm respectively;three-dimensional rotation errors were[Rtn:(0.53 ±0.49)°,Roll:(0.77 ± 0.75)°,Pitch:(0.71 ± 0.68)°]and[Rtn:(0.45 ± 0.49)°,Roll:(0.95 ± 0.75)°,Pitch:(0.71 ± 0.69)°]respectively(AP:t = 0.005,Roll:t = 0.003,P < 0.05). Conclusion Catalyst HD can improve the positioning accuracy of intensity-modulated radiotherapy after breast-conserving breast cancer with assisted styrofoam fixation. It is recommended to choose bilateral ROI when selecting the region of interest monitored by the Catalyst HD.