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中国癌症防治杂志

中国癌症防治杂志 ›› 2011, Vol. 3 ›› Issue (2): 125-.doi: 10.3969/j.issn.1674-5671.2011.02.08

• 临床研究 • 上一篇    下一篇

锥形束CT测量食管癌放射治疗的摆位误差

谢志原, 林育毅, 王永川, 吴君心, 陈辉林, 邵林东, 陈素真, 潘建基   

  • 出版日期:2011-08-03 发布日期:2011-08-03
  • 基金资助:

    福建省卫生教育联合攻关计划项目（WKJ2008-2-47-1）

XIE Zhi-Yuan, LIN Yu-Yi, WANG Yong-Chuan, WU Jun-Xin, CHEN Hui-Lin, SHAO Lin-Dong, CHEN Su-Zhen, PAN Jian-Ji   

  • Online:2011-08-03 Published:2011-08-03

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被引次数

16

摘要： 【摘要】目的 利用锥形束CT在线研究食管癌放疗时的摆位误差，计算CTV到PTV的外放边界（MPTV）。方法 应用医科达Synergy系统对食管癌患者治疗11例148次，分别在首次摆位后、摆位误差纠正后及治疗后行CBCT扫描，共获取444个CBCT信息，通过系统配有的匹配功能，获取的CBCT 图像与计划CT 图像相匹配，获取患者左右(X)、头脚(Y)和前后(Z)等3个方向的线性摆位误差，分析其摆位误差。结果11例患者共行444次CBCT，首次摆位后CBCT扫描，系统误差(均数)±随机误差(标准差)在X、Y、Z方向上分别为(-0.17±3.62)、(1.82±3.97)、(-2.34±2.10)mm，误差纠正后再次行CBCT，结果显示摆位误差明显缩小 (P＜0.05)。与纠正后比较，治疗后摆位误差增大，差异有统计学意义(P＜0.05)。纠正前X、Y、Z轴上MPTV分别为8.49、9.09、5.67mm，纠正后X、Y、Z方向的MPTV分别为1.80、2.47、2.21mm。结论本组病例食管癌放疗时Y方向摆位误差最大，X方向次之，Z方向最小；分次内误差在食管肿瘤治疗过程中变化明显，这在设计治疗计划时应予以考虑；通过CBCT获取食管癌患者的摆位误差并对其进行纠正，能显著降低分次间的摆位误差，提高放疗精确度，减小PTV外放边界。

关键词: 【关键词】食管肿瘤, 锥形束CT, 摆位误差, 外放边界

Abstract: 【Abstract】Objective To analyze the setup errors in radiotherapy on esophageal carcinoma by CBCT. Methods Patients received a total of 444 CBCT scans after the initial setup，re-positioning and radiation delivery. The CBCT images were registered to the planning CT images，and the setup errors on axe axes X，Y and Z were analyzed. Results a total of 11 patients received 444 CBCT. The setup errors were larger in the left-fight and superior-inferior directions comparing to the anterior-posterior direction. Compared with the initial setup errors，the re-positioning setup errors decreased significantly in all six axes(P＜0.05)The setup errors after radiation delivery were significantly increase comparing to the re-positioning setup errors(P＜0.05). Without real-time correction of setup errors，the estimated margins required for CTV-PTV was 8.49 mm in X-axis，9.09 mm in Y-axis and 5.67 mm in Z-axis. While with the real-time correction，the margins were only required 1.80 mm，2.47 mm and 2.21 mm in X，Y and Z axis，respectively. Conclusions The spatial distributions of setup errors were smallest in the anterior-posterior direction，moderate in the left-right direction and largest in the superior-inferior direction. The variations of intra-fractional setup error are obvious in esophageal tumors and should be taken into account during treatment planning. Real-time online correction of setup errors by CBCT can reduce the inter-fractional error，improve the precise of radiotherapy in patients with esophageal carcinoma，and reduce the CTV-PTV margin significantly.

Key words: 【Key words】 Esophageal neoplasm, Cone-beam computed tomography (CBCT)                 【Key words】 Esophageal neoplasm, Cone-beam computed tomography (CBCT), Setup errors, CTV-PTV margin