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Evaluation of the feasibility of log file-based three-dimensional independent dose verification system in quality assurance of intensity-modulated radiation therapy
Zhao Hanyi, Chang Sheng, Wang Dajiang, Zhang Yuemei, Bai Long, Li Guangjun
Radiation Physics Center,Cancer Center,WestChina Hospital,Sichuan University,Chengdu 610041,China (Zhao HY Present unit:Department of Oncology,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology,Wuhan 430030,China)
AbstractObjective To assess the feasibility of the log file-based three-dimensional independent dose verification system for the quality assurance of clinical radiotherapy. Methods The statistical values of the percentage depth dose,off-axis curves and output factor calculated by the Mobius system were statistically compared with the measured data by three-dimensional water tank. The three-dimensional independent dose verification in clinical radiotherapy plan and the acceleratr log file-based three-dimensional dose verification during the treatment were performed in 17 patients with nasopharyngeal cancer. The accuracy of dose calculation and reconstruction of Mobius system was assessed. A statistical analysis was performed on the intra-fractionalγpass rate (3%/3 mm) for each patient to evaluate the stability of intra-fractional radiotherapy. Results The percentage depth dose,off-axis curve and output factor statistically calculated by the Mobius system matched well with the data measured by three-dimensional water tank. The dose-volume histogram (DVH) parameters between the target area and organ at risk during clinical radiotherapy plan were statistically compared in 17 patients with nasopharyngeal cancer. The maximum deviation was-2.16% for the three-dimensional independent dose verification in the clinical radiotherapy plan,and 0.18 Gy for the accelerator log file-based three-dimensional dose verification. The averageγpass rate for 17 nasopharyngeal cancer patients was 99.26%,and the maximum deviation of intra-fractional radiotherapy was below 0.5%. Conclusions The function of dose reconstruction and independent calculation of the Mobius system yeilds the same accuracy with the treatment planning system,which can quickly perform three-dimensional independent dose verification in the clinical radiotherapy plan and accelerator log file-based three-dimensional dose verification throughout the treatment,thereby guarantting and providing the safe and reliable technical support for clinical treatment.
Fund:National Natural Science Foundation of China (81472807);Sichuan Provincial Health and Family Planning Commission Research Project (16PJ321);Undergraduate Training Program for Innovation and Entrepreneurship of Sichuan University (201610610721)
Corresponding Authors:
Li Guangjun,Email: gjnick829@sina.com
Cite this article:
Zhao Hanyi,Chang Sheng,Wang Dajiang et al. Evaluation of the feasibility of log file-based three-dimensional independent dose verification system in quality assurance of intensity-modulated radiation therapy[J]. Chinese Journal of Radiation Oncology, 2018, 27(10): 920-924.
Zhao Hanyi,Chang Sheng,Wang Dajiang et al. Evaluation of the feasibility of log file-based three-dimensional independent dose verification system in quality assurance of intensity-modulated radiation therapy[J]. Chinese Journal of Radiation Oncology, 2018, 27(10): 920-924.
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