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电子射野影像装置在容积调强旋转放疗多叶准直器到位精度质控中的应用

陈诚, 韩光, 周晓艺, 谭文勇, 王晓红

陈诚, 韩光, 周晓艺, 谭文勇, 王晓红. 电子射野影像装置在容积调强旋转放疗多叶准直器到位精度质控中的应用[J]. 肿瘤防治研究, 2015, 42(03): 261-265. DOI: 10.3971/j.issn.1000-8578.2015.03.011
引用本文: 陈诚, 韩光, 周晓艺, 谭文勇, 王晓红. 电子射野影像装置在容积调强旋转放疗多叶准直器到位精度质控中的应用[J]. 肿瘤防治研究, 2015, 42(03): 261-265. DOI: 10.3971/j.issn.1000-8578.2015.03.011
CHEN Cheng, HAN Guang, ZHOU Xiaoyi, TAN Wenyong, WANG Xiaohong. Application of Electronic Portal Imaging Device in Quality Control for Multileaf Collimator Position Accuracy of Volumetric-modulated Arc Therapy[J]. Cancer Research on Prevention and Treatment, 2015, 42(03): 261-265. DOI: 10.3971/j.issn.1000-8578.2015.03.011
Citation: CHEN Cheng, HAN Guang, ZHOU Xiaoyi, TAN Wenyong, WANG Xiaohong. Application of Electronic Portal Imaging Device in Quality Control for Multileaf Collimator Position Accuracy of Volumetric-modulated Arc Therapy[J]. Cancer Research on Prevention and Treatment, 2015, 42(03): 261-265. DOI: 10.3971/j.issn.1000-8578.2015.03.011

电子射野影像装置在容积调强旋转放疗多叶准直器到位精度质控中的应用

详细信息
    作者简介:

    陈诚(1980-),男,硕士,主管技师,主要从事放疗质量控制和医学图像处理的研究

    通讯作者:

    王晓红,E-mail: wangxh6711@163.com

  • 中图分类号: R730.55

Application of Electronic Portal Imaging Device in Quality Control for Multileaf Collimator Position Accuracy of Volumetric-modulated Arc Therapy

  • 摘要: 目的 研究利用电子射野影像装置(electronic portal imaging device,EPID)检测容积调强旋转放疗(volumetric-modulated arc therapy,VMAT)执行过程中多叶准直器(multileaf collimator,MLC)到位精度的方法。方法 随机选取了8例鼻咽癌患者的放疗计划进行分析,通过二维电离室矩阵进行剂量学验证,得到剂量验证通过率。借助Heimann Imaging Software拍摄软件和医科达Synergy直线加速器机载EPID,获取VMAT计划执行过程中MLC的到位信息,通过梯度检测算法获取MLC实际位置,并与VMAT计划中规定的MLC位置进行比较,得到MLC的位置误差,计算计划通过率。结果 8例鼻咽癌患者的放疗计划在评价标准为3%/3 mm时,剂量验证通过率是(94.8±2.1)%;当叶片到位误差允许值为1 mm时,叶片验证的通过率是(91.1±4.0)%。结论 8例VMAT计划全部通过了剂量验证,但仍存在不同程度的叶片到位误差,因此只对VMAT计划进行剂量验证是不够的,对VMAT计划剂量的验证需要对MLC进行专门的质量控制。通过EPID进行MLC到位精度的检测能够提供更详细、更深入的质控信息,为VMAT技术的开展提供更多的保障。

     

    Abstract: Objective To design a method for testing the accuracy of multileaf collimator(MLC) positions during the practice of the volumetric-modulated arc therapy (VMAT) plans with an electronic portal imaging device (EPID). Methods Eight VMAT plans for nasopharynx cancer were selected randomly for the analysis, Dose verification was carried out based on 2 Dion chamber array matrix to obtain the pass rate of dose verification. HIS(heimann imaging software) and EPID loaded in the Synergy Accelerator provided by Elekta were used to obtain the position information of MLC during the practice of VMAT. The actual positions of MLC were calculated with gradient algorithm and compared with MLC positions specified in VMAT plans, to find the position errors and calculate the passing rates of the plans. Results The pass rate of dose verification of 8 VMAT plans for nasopharynx cancer was (94.8±2.1)% with the distance-to-agreement criteria of 3%/3 mm; when the allowance error of MLC position accuracy was 1 mm, the pass rate of leaf's position verification was (91.1±4.0)%. Conclusion All 8 VMAT plans have passed the dose verification, but there are still MLC position errors of different degrees. So only Dose verification of patient-specific VMAT plan was not sensitive enough to detect the tiny MLC positon errors, so additional MLC QA is needed. The detection of MLC positions accuracy with EPID could provide more detailed and underlying quality control information, thus, to provide more guarantee for the application of VMAT.

     

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出版历程
  • 收稿日期:  2014-06-12
  • 修回日期:  2014-07-22
  • 刊出日期:  2015-03-24

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