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中国癌症防治杂志

中国癌症防治杂志 ›› 2013, Vol. 5 ›› Issue (2): 134-138.doi: 10.3969/j.issn.1674-5671.2013.02.12

• 临床研究 • 上一篇    下一篇

不同射野角度的鼻咽癌调强放疗计划的比较研究

  

  1. 广东省佛山市第一人民医院肿瘤中心放疗科
  • 出版日期:2013-06-25 发布日期:2013-06-27
  • 通讯作者: 石锦平 E-mail:rath55@126.com
  • 基金资助:

    广东省佛山市卫生局科研基金资助项目（2011064）

Comparison of different beam arrangements in intensity-modulated radiation therapy to treat nasopharyngeal carcinoma

  • Online:2013-06-25 Published:2013-06-27

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被引次数

11

摘要：  目的 研究不同射野角度的鼻咽癌调强放疗靶区和周围正常组织、危及器官的计划剂量学分布的差异。方法 选择11例鼻咽癌患者行调强放疗，每例患者按照相同的处方剂量要求在治疗计划系统中设计3套计划：7野均匀分布为A计划（每野角度间隔51°）；前7野为B计划（每野角度间隔42°）；非共面7野为C计划（其中共面5野均分,每野间隔72°，非共面2野床角90°，机架角330°及30°）。计划均采用相同的处方剂量条件进行优化，比较3组计划靶区和危及器官的剂量分布、剂量体积直方图（DVH）、靶区适形度指数（CI）、平均剂量Dmean、最小剂量、最大剂量等参数。结果 3组计划靶区的剂量分布基本相同。对于脑干、脊髓所接受的D1剂量，3组计划之间差别较小，均在耐受剂量范围以内， B计划稍大于A计划、C计划。颞叶D33的剂量A计划比B计划、C计划分别降低9.28%、12.38%。对于颞颌关节、腮腺等并行器官所接受的D50剂量，C计划分别低于A计划、B计划，颞颌关节C计划分别比A计划、B计划降低30.47%、33.29%。口腔黏膜的受照平均剂量， C计划分别比A 计划、B计划增加10.49%和10.85%。结论 鼻咽癌7野调强放疗可以满足靶区的剂量需求，设计个体化的最优调强放疗计划时，应考虑肿瘤体积的大小和生长部位，选择合适的设野和优化条件，有望获得较好的剂量分布，且可明显降低正常组织并发症的发生率。

关键词:  , 鼻咽肿瘤, 射野角度, 调强放疗, 剂量分布

Abstract: Objective To compare different beam arrangements in 7-field intensity-modulated radiation therapy（IMRT） to treat nasopharyngeal carcinoma by analyzing doses delivered to target tissue and adjacent normal tissue. Methods A total of 12 patients with nasopharyngeal carcinoma who had been prescribed the same total IMRT dose were treated with one of the following three IMRT plans：average plan，with a beam angle interval of 51°；anterior plan，with a beam angle interval of 42°；and a non-coplanar plan，involving 5 coplanar fields with a beam angle interval of 72°，as well as 2 non-coplanar fields with a couch angle of 90° and gantry angles of 30° and 330°. All plans were optimized using the same constraints to ensure comparability of the results.The following out-comes were measured：dose distribution to the planned target volume（PTV） and to organs at risk，dose volume histogram，PTV confor-mity index，mean dose（Dmean），minimum dose，and maximum dose（Dmax）. Results The three IMRT plans provided similar dose distributions to the PTV.The anterior plan provided a slightly higher Dmax-1%（D1） to the spinal cord and brain stem than did the other plans，but this difference was very small and within the range of tolerated doses.The average plan provided a temporal lobe dose D33 that was 9.28% smaller than that of the anterior plan and 12.38% smaller than that of the non-coplanar plan.The non-coplanar plan provided a lower D50 to the parotid gland and temporomandibular joint than did the other plans，and the non-coplanar plan provided a temporomandibular joint dose D50 that was 30.47% smaller than that of the average plan and 33.29% smaller than that of the anterior plan.The non-coplanar plan provided an oral mucosa Dmean that was 10.49% higher than that of the average plan and 10.85% higher than that of the anterior plan. Conclusion Satisfactory dose coverage in the nasopharyngeal carcinoma target volume was achieved using 7-field IMRT.By designing individualized IMRT plans based on the location and volume of the target area， and by optimizing the type of beam arrangement，the dose distribution can be improved and the risk of affecting normal tissue signifi-cantly reduced.

Key words:  Nasopharyngeal neoplasms, Beam angle, Intensity-modulated radiation therapy, Bose distribution