锥型束CT对鼻咽癌调强放射治疗患者摆位精度的影响  

The Influence of the Cone Beam CT on Positioning Accuracy of Intensity Modulated Radiotherapy for Nasopharyngeal Carcinoma

作　　者：杨志勇[1] 王继平[1] 袁红[1] 陈传喜[1] 赵德英 Yang Zhiyong;Wang Jiping;Yuan Hong;Chen Chuanxi;Zhao Deying(The Radiotherapy Department,Huanggang Central Hospital,Huanggang Hubei 438000,China)

机构地区：[1]黄冈市中心医院放疗科,湖北黄冈438000

出　　处：《医疗装备》2018年第21期49-51,共3页Medical Equipment

摘　　要：目的探讨锥型束CT(CBCT)对鼻咽癌调强放射治疗患者摆位精度的影响,为图像引导技术减少鼻咽癌患者摆位误差提供更多的依据。方法利用Varian 23IX直线加速器机载的千伏级CBCT对28例鼻咽癌调强适形放射治疗患者于每次治疗前进行扫描,分别于第l、3、5、7、ll、18、25次照射前进行CBCT扫描,共计得到196次CBCT影像。通过图像融合软件将计划CT图像与CBCT影像匹配,得到靶区中心的摆位误差,在线修正后,得到56次CBCT影像,再匹配后得到修正后靶区偏差;在治疗完成后重新扫描23次,得到治疗后靶区中心。结果 28例患者共接受了196次首次摆位CBCT扫描,摆位前X方向偏差为(1.43±2.00)mm,Y方向偏差为(1.76±1.62)mm,Z方向偏差为(1.04±1.41)mm;3个方向≤2 mm的偏差比例分别为78.57%,84.18%,88.26%。3个方向任一偏差>2 mm时进行在线修正,得到3个方向的偏差:X方向为(0.04±0.12)mm,Y方向为(0.06±0.12)mm,Z方向为(0.02±0.14)mm;3个方向≤2 mm的偏差比例均为100.00%。治疗完成后重新扫描23次CBCT,经过图像匹配后得到3个方向的偏差:X方向为(0.17±0.34)mm,Y方向为(0.13±0.45)mm,Z方向为(0.09±0.64)mm;3个方向≤2 mm的偏差比例均为100.00%。结论通过图像引导放射治疗技术对鼻咽癌患者进行治疗前、中、后的在线或离线的位置验证,监测和校正,可以减少治疗摆位和肿瘤因位置移动造成的误差,提高肿瘤的局部控制率,减少正常组织的损伤,提高放射治疗的效果。Objective To investigate the influence of cone beam CT(CBCT)on positioning accuracy of intensity modulated radiotherapy for nasopharyngeal carcinoma patients,and provide more basis for image guidance technology to reduce positioning error of nasopharyngeal carcinoma patients.Methods Using CBCT of Varian 23IX to acquire the images of the 28 nasopharyngeal carcinoma patients during the intensity-modulated radiation therapy treatment,we respectively scanned the patients before the lst,3rd,5th,7th,llth,18th,25th treatment,and got 196 times CBCT images.We matched the CT images with CBCT through the image fusion software to get the positioning error,and then got 56 times CBCT images through revising the target center online;We matched again after getting the revised target deviation;And then rescanned 23 times to get the target center.Results 28 patients accepted 196 times CBCT scanning after initial setup,and the errors were(1.43±2.00)mm in X direction,(1.76±1.62)mm in Y direction,(1.04±1.41)mm in Z direction before pendulum;These three directions deviation ratios≤2 mm were 78.57%,84.18%,88.26%respectively.All these directions>2 mm were revised through the online correcting respectively,and we got a new deviation in three directions:X direction was(0.04±0.12)mm,Y direction was(0.06±0.12)mm,Z direction was(0.02±0.14)mm;Three directions deviation≤2 mm were 100.00%.After rescanning 23 times after the completion of treatment,we got three direction deviation:X direction was(0.17±0.34)mm,Y direction was(0.13±0.45)mm,Z direction was(0.09±0.64)mm after images matching;Three directions deviation≤2 mm were 100.00%.Conclusion Because of the application of Image-guided radiotherapy for nasopharyngeal carcinoma patients treating,we can verificate the patients'on-line or off-line position before,during or after the treatment.Moreover,we might monitor and correct the error caused by the treatment so as to reduce the errors of the treatment position and tumor positioning,improve the tumor control rate,and thus reducing

关 键 词：锥形束CT 鼻咽癌 影像匹配 在线 离线 

分 类 号：R739.6[医药卫生—肿瘤]