| Li Guangjun,Li Yanlong,Yuan Qingqing,et al.The dosimetric impacts of accelerator operation error on the volumetric modulated arc therapy for cervical cancer[J].Chinese Journal of Radiological Medicine and Protection,2018,38(11):824-829 |
| The dosimetric impacts of accelerator operation error on the volumetric modulated arc therapy for cervical cancer |
| Received:May 21, 2018 |
| DOI：10.3760/cma.j.issn.0254-5098.2018.11.005 |
| KeyWords:Dosimetry Volumetric modulated arc therapy Linear accelerator Position accuracy |
| FundProject:国家自然科学基金（81472807）；四川省卫计委科研项目（16PJ321） |
| Author Name | Affiliation | E-mail | | Li Guangjun | Radiotherapy Department of Cancer Center of West China Hospital, Sichuan University, Chengdu 610041, China | | | Li Yanlong | Department of Oncology, The Second Xiangya Hospital of Central South University, Changsha 410011, China | | | Yuan Qingqing | School of Physics and Technology, Wuhan University, Wuhan 430072, China | | | Wang Dajiang | Department of Radiation Oncology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China | | | Wang Qiang | Radiotherapy Department of Cancer Center of West China Hospital, Sichuan University, Chengdu 610041, China | | | Xiao Jianghong | Radiotherapy Department of Cancer Center of West China Hospital, Sichuan University, Chengdu 610041, China | | | Bai Sen | Radiotherapy Department of Cancer Center of West China Hospital, Sichuan University, Chengdu 610041, China | baisen@scu.edu.cn |
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| Abstract:: |
| Objective To investigate the dosimetric effect of accelerator gantry rotation angle errors, collimator and multileaf collimator (MLC) leaf position errors on volumetric-modulated arc therapy (VMAT) for cervical cancer. Methods A total of 10 patients with cervical cancer were selected. The plan.Trail file of each clinical plan was extracted from the Pinnacle3 V9.2 planning system of USA Philips, then the operating parameters of tach control point were read and modified by Matlab programs, and thus the operating error of the accelerator was simulated. Results In this paper, it was discovered that systematic accelerator gantry rotation angle errors, systematic collimator position errors and systematic MLC shift errors which led to the maximum changes of the PTV dose limit were 0.16%, 0.46% and 0.57%, respectively, and the maximum changes of the dose limit of organs at risk (OAR) were 0.38%, -1.32% and -0.44%, respectively. When the systematic MLC gap width errors were±0.5,±1 and±2 mm, respectively, the maximum changes of PTV dose were 2.11%, 3.04% and 6.03%, respectively, while the maximum changes of the OAR average dose were 2.17%, 3.92% and 7.97%, respectively. Furthermore, the dose limits of PTV and OAR showed a strong linear correlation with MLC open or close errors(t=21.201~90.562,P<0.05). If actual errors of each parameter of accelerator were introduced, the maximum changes of PTV and OAR dose limits were 0.16% and 1.30%, respectively, and conformity index (CI) and homogeneity index (HI) were barely changed. Conclusions No significant effect was found for systematic accelerator gantry rotation angle errors, systematic collimator position errors and systematic MLC shift errors for cervical cancer VMAT patients. However, there is a high sensitivity to dose distribution for MLC open or close errors. Therefore, it is necessary to pay more attention on the quality control of the accelerator running in particular MLC position errors to ensure the therapeutic accuracy. |
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