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利用CBCT联合六自由度治疗床研究宫颈癌术后放疗摆位误差及CTV外放边界
姚丽红, 朱丽红, 王俊杰, 曹倩倩, 曲昂, 周舜, 姜树坤, 王巍, 孙海涛, 林蕾
100191 北京大学第三医院放疗科
Analysis of setup errors and planning target margin by cone-beam CT in combination with HexaPOD evo RT 6D couch for postoperative patients of cervical cancer
Yao Lihong, Zhu Lihong, Wang Junjie, Cao Qianqian, Qu Ang, Zhou Shun, Jiang Shukun, Wang Wei, Sun Haitao, Lin Lei
Department of Radiation Oncology,Third Hospital of Peking University,Beijing 100191, China
Abstract：Objective To evaluate the setup errors and CTV margins by kV cone-beam CT in combination with HexaPOD evo RT 6D treatment couch for postoperative patients with cervical cancer. Methods Between July 2013 and March 2014,17 postoperative patients with cervical cancer were prospectively enrolled in the study. Each patient would scan the first CBCT after conventional positioning,and their scan after 6D couch online correction,and the last scan after delivery. Then the scans were registered to the planning CT to determine the inter-and intrafractional setup errors in translational and rotational directions. PTV margins were calculated from the systematic (∑) and random (σ) errors. Results Data set for a total of 676 CBCT scans were obtained from the 17 patients, in which before and after the 6D couch correction were both 304 and after delivery was 68.The interfractional setup errors in translational and rotational directions by 6D couch online correction were significantly decreased. The average absolute values of the pre-/post-correction errors were 2.42 mm/0.42 mm x-axis,3.55 mm/0.47 mm y-axis,3.26 mm/0.27 mm z-axis,1.24°/0.24°pitch,0.70°/0.32°roll,0.57°/0.12°yaw, respectively (P=0.036,0.000,0.000,0.002,0.000,0.004). The total PTV margins (MPTV) accounting for 6D couch online correction and intrafraction errors were 2.24,3.32,2.20 mm in the left-right (x-axis),superior-inferior (y-axis) and anterior-posterior (z-axis) directions, respectively. Conclusions CBCT in combination with HexaPOD evo RT 6D is an effective modality to evaluate and improve the accuracy of IMRT in postoperative patients with cervical cancer,while putting narrow target margin to reduce the irradiation of normal tissues.
Yao Lihong,Zhu Lihong,Wang Junjie et al. Analysis of setup errors and planning target margin by cone-beam CT in combination with HexaPOD evo RT 6D couch for postoperative patients of cervical cancer[J]. Chinese Journal of Radiation Oncology, 2015, 24(1): 78-81.
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2015, Vol. 24 
