[1]邓莹,张美芳,孙文钊,等.有无均整器模式下臂架与准直器不同角度条件下的剂量学比较[J].中国医学物理学杂志,2020,37(8):958-964.[doi:DOI:10.3969/j.issn.1005-202X.2020.08.004]
　DENG Ying,ZHANG Meifang,et al.Dosimetric comparison at different gantry and collimator angles in flattening filter-free or flattening filter mode[J].Chinese Journal of Medical Physics,2020,37(8):958-964.[doi:DOI:10.3969/j.issn.1005-202X.2020.08.004]
点击复制

有无均整器模式下臂架与准直器不同角度条件下的剂量学比较()
分享到：

《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]

卷:
37
期数:
2020年第8期
页码:
958-964
栏目:
医学放射物理
出版日期:
2020-08-27

文章信息/Info

Title:
Dosimetric comparison at different gantry and collimator angles in flattening filter-free or flattening filter mode
文章编号:
1005-202X（2020）08-0958-07
作者:
邓莹1; 2; 张美芳1; 2; 孙文钊1; 陈利1; 杨鑫1; 黄晓延1
1.中山大学肿瘤防治中心/华南肿瘤学国家重点实验室/肿瘤医学协同创新中心/广东省鼻咽癌诊治研究重点实验室， 广东 广州 510060；2.中山大学新华学院， 广东 广州 510520
Author(s):
DENG Ying1;  2;  ZHANG Meifang1;  2;  SUN Wenzhao1;  CHEN Li1;  YANG Xin1;  HUANG Xiaoyan1
1. Sun Yat-sen University Cancer Center/State Key Laboratory of Oncology in South China/Collaborative Innovation Center for Cancer Medicine/Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China 2. Xinhua College of Sun Yat-sen University, Guangzhou 510520, China
关键词:
无均整器; 等中心点; 剂量; 治疗床; 衰减因子
Keywords:
Keywords: flattening?ilter-free isocenter dose treatment couch attenuation factor
分类号:
R312；R811.1
DOI:
DOI:10.3969/j.issn.1005-202X.2020.08.004
文献标志码:
A
摘要:
目的：探讨臂架或准直器角度的改变对均整（FF）与非均整（FFF）两种模式的射线剂量的影响。方法：选用Versa HD直线加速器配备的6 MV/10 MV光子束FF/FFF模式4档能量在设定好九点位置的10 cm×10 cm标准射野内进行实验。首先，借助IMF等中心夹具将Mapcheck2固定于治疗机机头，并用Mapcheck2测量相同臂架与准直器角度条件下4种光子束输出的平面剂量值；其次，用Mapcheck2测量在相同臂架角度、不同准直器角度与相同准直器角度、不同臂架角度两种条件下4种光子束的中心轴剂量值；最后，固定准直器为0°，设立两组臂架对穿射野（0°与180°，90°与270°）。拆除Mapcheck2，采用固体水和FC65-G电离室建立一个测量模体来测量4种光子束在两组等中心对穿野的剂量。运用SPSS统计软件对该实验收集到的数据进行对比分析。结果：在相同臂架与准直器角度条件下，4种光子束辐照9个点的平面剂量之间均存在明显统计学差异（P6 MV FF =0.020, P6 MV FFF=0.017, P10 MV FF =0.030, P10 MV FFF=0.016）；而不同臂架角度或不同准直器角度条件下，4种能量光子束的中心轴点剂量值均无统计学差异。在0°与180°的对穿野，4种能量光子束的输出剂量存在统计学差异（P6 MV FF =0.001, P6 MV FFF=0.002, P10 MV FF =0.003, P10 MV FFF=0.001），而在90°与270°的对穿野无统计学差异。结论：Versa HD直线加速器拥有优良的机械等中心性能。在实际工作时，臂架和准直器的旋转，均不影响光子束的中心轴剂量的准确输出。在FF模式下，射线能量越高，受治疗床影响越小；FFF模式射线由于射线质软，能量越高，更易受到治疗床的衰减作用，在实际中应引起重视。
Abstract:
Abstract: Objective To investigate the effects of different gantry angles or collimator angles on dose output in flattening filter-free (FFF) or flattening filter (FF) mode. Methods Two kinds of photon beam energies (6 MV and 10 MV) in FFF or FF mode in Versa HD linear accelerator were selected for the experiment. The dose measurements were performed at 9 points in the standard field of 10 cm×10 cm. Firstly, after that Mapcheck2 was fixed at the head of the treatment machine with the assistance of an isocentric fixture tool IMF, Mapcheck2 was used to measure the planar doses output by 4 kinds of photon beams at the same angles of gantry and collimator. Then the central axis doses of 4 kinds of photon beams in two cases (at the same gantry angle and different collimator angles at the same collimator angle and different gantry angles) were measured. Finally, the collimator was fixed at 0° and two sets of gantry were set up to pass through the irradiation field (0° and 180°, 90° and 270°). Mapcheck2 was removed, and then solid water and FC65-G ionization chamber were used to build a measurement phantom for measuring the dose of 4 kinds of photon beams in two groups of isocenter parallel-opposed fields. The data collected in this experiment were compared and analyzed by SPSS statistical software. Results When the angles of gantry and collimator were kept consistent, there were significant differences in the planar doses at 9 points irradiated by 4 kinds of photon beams (P6 MV FF =0.020, P6 MV FFF=0.017, P10 MV FF =0.030, P10 MV FFF=0.016). In the cases of different gantry angles or different collimator angles, there was no statistical difference in the central axis dose of 4 kinds of photon beams. The output doses of the 4 kinds of photon beams were significantly different in the parallel-opposed fields of 0° and 180° (P6 MV FF =0.001, P6 MV FFF=0.002, P10 MV FF =0.003, P10 MV FFF=0.001), but there were no significant difference in the parallel-opposed fields of 90° and 270°. Conclusion Versa HD linear accelerator has excellent mechanical isocentric performances. The rotation of both the gantry and the collimator does not affect the accurate output of the central axis dose of the photon beam in practice. In FF mode, the higher the energy is, the smaller the dose attenuation caused by the treatment couch is. Due to the softness of beams and the higher the energy in FFF modes, the output dose is more easily affected by the attenuation effect of the treatment couch, which should be pay attention to in practice.

相似文献/References:

[1]桑勇,单国平,祝成龙,等. 静态调强放疗等中心点对鼻咽癌剂量学的影响[J].中国医学物理学杂志,2019,36(4):394.[doi:DOI:10.3969/j.issn.1005-202X.2019.04.005]
　SANG Yong,SHAN Guoping,ZHU Chenglong,et al. Dosimetric effects of isocenter on static intensity-modulated radiotherapy for nasopharyngeal carcinoma[J].Chinese Journal of Medical Physics,2019,36(8):394.[doi:DOI:10.3969/j.issn.1005-202X.2019.04.005]
[2]黄霞,苏坤普,罗焕丽,等.铅门跟随与固定技术结合有无均整器模式的鼻咽癌IMRT剂量学比较[J].中国医学物理学杂志,2020,37(7):858.[doi:DOI:10.3969/j.issn.1005-202X.2020.07.011]
　HUANG Xia,SU Kunpu,LUO Huanli,et al.Different intensity-modulated radiotherapy plans for nasopharyngeal carcinoma: a dosimetric comparison among JTT-FFF, JTT-FF, SJT-FFF and SJT-FF[J].Chinese Journal of Medical Physics,2020,37(8):858.[doi:DOI:10.3969/j.issn.1005-202X.2020.07.011]

备注/Memo

备注/Memo:
【收稿日期】2020-02-21 【基金项目】广州市珠江科技新星专项资助（201710010162）；广东省自然科学基金（2017A030310217）；大学生创新创业训练计划项目（20191390109, 201813902075, 201813902071, 201713902050） 【作者简介】邓莹，研究方向：放射治疗技术，E-mail: dengy.guang@foxmail.com 【通信作者】杨鑫，博士，硕士生导师，助理研究员，研究方向：医学物理、生物医学工程、放疗质控质保，E-mail: yangxin@sysucc.org.cn；黄晓延，硕士，副主任技师，研究方向：放射治疗过程中的质量控制，E-mail: huangxiaoy@sysucc.org.cn
更新日期/Last Update: 2020-08-27