摘要
目的 评估光学体表引导放疗技术(surface guided radiation therapy, SGRT)在乳腺癌保乳放疗患者日常摆位应用的准确性。方法 以ELEKTA infinity加速器行乳腺癌保乳术后放疗的40例患者为研究对象,患者使用光学体表监测系统(optical surface monitoring system, OSMS)摆位,前3次治疗均行锥形束CT(cone-beam computed tomography, CBCT)验证,后续每周至少1次。记录OSMS摆位、CBCT配准和体表标记线对应的左右(ML)、头脚(SI)、前后(AP)的床值,分析OSMS与CBCT的差值(SG)和体表标记线与CBCT的差值(SM)之间的差异,并统计SG和SM的误差频值、SG摆位的旋转角度;用Bland-Altman法评估SG与CBCT的一致性;根据计划靶区外放公式MPTV=2.5Σ+0.7σ计算SG和SM的外扩边界。结果 SG在ML、SI、AP方向平移误差的中位数(0~0.1 cm)均小于SM(0~0.3 cm),差异有统计学意义(P<0.05);SG在ML、SI、AP方向平移误差绝对值≤0.3 cm的比例分别比SM高14.8%、16.3%、35.1%,SG摆位的Pitch、Roll、Yaw旋转误差中位数区间为(-0.10~0.10)°;在Bland-Altman散点图中,ML、SI、AP 3个平移方向上,SG与CBCT的差值均值为0.03 cm、0.01 cm和0.13 cm;SG和SM在ML、SI、AP方向的M值分别为(0.36 cm、0.38 cm、0.30 cm)、(0.66 cm、0.82 cm、0.93 cm)。结论 在乳腺癌保乳放疗中,SGRT引导摆位可以有效地减少摆位误差,降低PTV外扩边界,与CBCT具有较好的一致性。
Objective To evaluate the accuracy of surface guided radiation therapy(SGRT)in daily positioning of breast-conserving radiotherapy.Methods Retrospective analysis was performed on 40 breast cancer patients who underwent ELEKTA infinity accelerator radiotherapy.Patients were positioned by the optical surface monitoring system(OSMS).The first three fractions and once weekly cone-beam computed tomography(CBCT)images were retrieved for data analysis.The couch parameters of the OSMS positioning,CBCT registration and the skin markers were recorded in lateral(ML),longitudinal(SI)and vertical(AP)directions,respectively.The difference between the surface guidance(SG)of OSMS and CBCT and the skin marker(SM)of CBCT was calculated and compared.The results were compared using nonparametric tests,and the rotation of SG positioning and the proportion of SG and SM were statistically analyzed.The Bland-Altman plot was used to analyze the consistency between SG and CBCT.Planning target volume(PTV)margins(M)were calculated using the formula MPTV=2.5Σ+0.7σ.Results The median errors in the ML,SI,and AP translation directions for SG(0-0.1 cm)were smaller than those for SM(0-0.3 cm),with statistically significant differences(P<0.05).The proportion of absolute values of errors≤0.3 cm in the ML,SI,and AP directions for SG was 14.8%,16.3%,and 35.1%higher,respectively,than for SM.The median range of Pitch,Roll,and Yaw rotation errors for SG positioning was(-0.10-0.10)°.In the Bland-Altman scatter plot,the mean differences between SG and CBCT in the ML,SI,and AP directions were 0.03 cm,0.01 cm,and 0.13 cm,respectively.The M values for SG and SM in the ML,SI,and AP directions were(0.36 cm,0.38 cm,0.30 cm)and(0.66 cm,0.82 cm,0.93 cm),respectively.Conclusion In breast-conserving radiotherapy for breast cancer,SGRT-guided positioning can effectively reduce positioning errors,decrease the external expansion boundary of the PTV,and demonstrate good consistency with CBCT.
作者
刘金迪
朱秋芳
王亚娟
何振宇
陈雪梅
LIU Jin-di;ZHU Qiu-fang;WANG Ya-juan;HE Zhen-yu;CHEN Xue-mei(Department of Radiotherapy,South China State Key Laboratory of Oncology,Sun Yat-sen University Cancer Center,Guangzhou 510060,Guangdong,China;不详)
出处
《广东医学》
2023年第12期1459-1464,共6页
Guangdong Medical Journal
基金
国家自然科学基金项目(81872459)。
关键词
乳腺癌
光学体表引导技术
锥形束CT
放射治疗
摆位误差
外扩边界
breast cancer
surface guided radiation therapy
cone-beam computed tomography
radiotherapy
setup error
margin
