CBCT图像引导下胸部肿瘤放疗摆位误差及其外放边界  

Analysis of setup errors and margin for thoracic carcinoma radiotherapy with cone-beam CT-based image guidance

作　　者：曹晓辉[1] 刘明[1] 翟福山[1] 王安峰[1] 杨永锋[1] 刘兵[1] 包超恩[1] 白研[1] 

机构地区：[1]河北医科大学第三医院放疗科,石家庄,050051

出　　处：《中华放射肿瘤学杂志》2014年第1期53-55,共3页Chinese Journal of Radiation Oncology

摘　　要：目的研究千伏级CBCT引导下胸部肿瘤放疗中摆位误差及其外放边界。方法采用瓦里安Ix直线加速器机载影像系统对34例胸部肿瘤患者三维放疗前行CBCT，系统自动重建图像并与治疗计划CT图像相匹配，获得患者左右、上下、前后方向摆位误差，计算PTV及OAR外放边界。结果共行279次扫描，考虑误差方向时左右、上下、前后方向误差分别为（-0．16±3．25）、（-1．36±5．43）、（-2．43±2．14）mm，只考虑误差大小时左右、上下、前后方向误差分别为（2．41±2．18）、（4．27±3．60）、（2．71±1．77）mm。PTV在左右、上下、前后方向外放边界分别为2．68、7．19、7．57mm。结论本院胸部肿瘤患者应用热塑体膜固定，存在-定程度摆位误差。靶区在左右、上下、前后方向外前沩界钋别为2．687．19、7．57mm．Objective To study the role of KV CBCT on the geometrical accuracy of three- dimensional conformal radiotherapy （3DCRT） and to evaluate the margin of targets and peripheral OAR for thoracic carcinoma. Methods 34 patients with thoracic carcinoma were enrolled. Varian-IX liuac with OBI system was used to acquire CBCT scans before delivery in 3DCRT. The left-right （x）, superior-inferior （y）, anterior-posterior （z） setup errors of patients can be obtained from the tomography images automatically restructured by the system. Results According to 279 CBCT scans the systemic ＋ random error on x, y, z directions were （ - 0. 16± 3.25 ） mm, （ - 1.36 ±5.43） mm, （ - 2.43± 2. 14） mm and （ 2.41±2. 18 ） mm, （4.27 ± 3.60） mm, （2.71 ± 1.77 ） mm respectively if we do not consider the direction of setup errors. The margins of targets were calculated as 2. 68 mm, 7. 19 mm and 7. 57 mm respectively. Conclusions Setup errors are unavoidable in thoracic carcinoma irradiation. We suggest a PTV margin of 2. 68 mm, 7. 19 mm and 7. 57 mm in the left-right, superior-inferior and anterior-posterior directions respectively in our department.

关 键 词：胸部肿瘤 影像引导放射疗法 体层摄影术 X线计算机 锥形束 摆位误差 外放边界 

分 类 号：R734[医药卫生—肿瘤] R730.44[医药卫生—临床医学]