摘要
目的研究锥形束CT(CBCT)在乳腺癌保乳术后放疗中离线校正治疗等中心的作用。方法随机选取接受放疗的乳腺癌保乳术后患者30例,均采用调强放射治疗,前3次治疗前均对患者行CBCT扫描,离线计算3次摆位误差均值,依据误差均值调整患者治疗等中心,后续治疗过程中每周1次CBCT扫描,计算调整前后PTV外扩值(M)。采集的CBCT图像以计划CT作为基准,应用Grey_(T+R)匹配分别对整体区域(GROI)、患侧胸壁区域(CROI)、患侧锁骨头区域(SROI)进行图像配准,记录离线校正治疗等中心前后的平移和旋转误差情况。结果离线校正治疗等中心后,X轴(左右)、Y轴(头脚)及Z轴(前后)方向上的平移误差均值从0.4 cm减少至0.1 cm,差异有统计学意义(P<0.05)。在左右、头脚、前后方向上的M值分别由调整前的0.54、0.76、0.62 cm变成了修正后的0.17、0.17、0.19 cm。配准区域分别选择GROI、患侧CROI、患侧SROI进行Grey_(T+R)匹配,结果发现GROI、CROI和SROI在X轴上的平移误差、Y轴旋转误差上的差异无统计学意义(P>0.05),其他方向和旋转角度上差异有统计学意义(P<0.05)。结论乳腺癌保乳术后调强放疗应用锥形束CT扫描离线校正可以作为复位的有效补充,调整等中心后可以有效降低摆位误差。
Objective To study the effect of cone-beam CT(CBCT)on off-line correction therapy and its effect on positioning error in postoperative radiotherapy for breast cancer.Methods 30 cases of postoperative patients with breast cancer confirmed breast radiotherapy in our center were randomly selected.All patients received intensity-modulated radiotherapy.Three CBCT scanning was given before the first 3 treatments,and the mean beam position errors were assessed using off-line calculation,on the basis of which adjustments of treatment center were made.During the follow-up treatment,CBCT scanning was performed once a week,and PTV expansion value(M)before and after adjustment was calculated.Planned CT was used as the baseline for the collected CBCT images,and Grey_(T+R) matching was used to register the global region(GROI),affected chest wall region(CROI)and affected clavicular head region(SROI);and the translation and rotation errors before and after off-line correction therapy were recorded.Results After off-line correction,the mean translation errors of X axis(left and right),Y axis(head and foot)and Z axis(front and back)decreased from 0.4 cm to 0.1 cm,and the differences were significant(P<0.05).The M values in left and right,head and foot,and front and back directions changed from 0.54,0.76 and 0.62 cm,respectively,before adjustment to 0.17,0.17 and 0.19 cm,respectively,after correction.The global region(GROI),the affected chest wall region(CROI)and the affected clavicle head region(SROI)were selected for Grey_(T+R) matching.The results showed that compared with GROI,CROI and SROI had no statistical significance in translation error of X axis and rotation error of Y axis(P>0.05),while significant differences in other directions and rotation angles were recorded(P>0.05).Conclusion The off-line correction based on cone-beam CT scan in intensity modulated radiotherapy after breast conserving surgery can be an effective supplement in reduction of positioning error.
作者
陈雪梅
黄晓彤
蔡维洵
刁文超
朱金汉
何振宇
姜晓勃
CHEN Xue-mei;HUANG Xiao-tong;CAI Wei-xun;DIAO Wen-chao;ZHU Jin-han;HE Zhen-yu;JIANG Xiao-bo(Department of Radiotherapy,Sun Yat-sen University Cancer Center,Guangzhou 510060,Guangdong,China;不详)
出处
《广东医学》
CAS
2022年第7期811-816,共6页
Guangdong Medical Journal
基金
国家自然科学基金面上项目(81872459)
广东省自然科学基金资助项目(2018A030313666)。
关键词
乳腺癌
放疗
锥形束CT
整体配准
局部配准
摆位误差
breast cancer radiotherapy
cone beam CT
overall registration
local registration
beam position error
