| Huang Zike,Yang Cui,Wang Jiazhou,Hu Weigang,Han Xu.The effect of environmental radiation of radiotherapy workplace on stereotactic radiation therapy plan dose verification using an Exradin W1 scintillator detector[J].Chinese Journal of Radiological Medicine and Protection,2021,41(5):368-373 |
| The effect of environmental radiation of radiotherapy workplace on stereotactic radiation therapy plan dose verification using an Exradin W1 scintillator detector |
| Received:November 27, 2020 |
| DOI：10.3760/cma.j.issn.0254-5098.2021.05.009 |
| KeyWords:Plastic scintillator detector Dose verification Stereotactic radiation therapy plans Quality assurance |
| FundProject: |
| Author Name | Affiliation | E-mail | | Huang Zike | Department of Radiation Oncology, Cancer Hospital, Departmentof Oncology, Shanghai Medical college, Fudan University, Shanghai 200032, China | | | Yang Cui | Department of Radiation Oncology, Cancer Hospital, Departmentof Oncology, Shanghai Medical college, Fudan University, Shanghai 200032, China | | | Wang Jiazhou | Department of Radiation Oncology, Cancer Hospital, Departmentof Oncology, Shanghai Medical college, Fudan University, Shanghai 200032, China | | | Hu Weigang | Department of Radiation Oncology, Cancer Hospital, Departmentof Oncology, Shanghai Medical college, Fudan University, Shanghai 200032, China | | | Han Xu | Department of Radiation Oncology, Cancer Hospital, Departmentof Oncology, Shanghai Medical college, Fudan University, Shanghai 200032, China | jimmyhan244@126.com |
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| Abstract:: |
| Objective To study the influence of environmental radiation of radiotherapy workplace on the stereotactic radiation therapy(SRT) plan absolute dose verification with plastic scintillator detector Exradin W1. Methods The computed tomography (CT) image of the stereotactic dose verification phantom (SDVP) was scanned and imported into the treatment planning system. Three schemes, including 3 cm×3 cm to 20 cm×20 cm square gradient field irradiation, virtual planning target volume(PTV) non-coplanar arcs irradiation and 10 cases of volumetric modulated arc radiotherapy SRT (VMAT SRT) clinical plan verification, were measured with or without a home-made shield over the photodiode. Measurements were recorded to analyze the impact of environmental radiation on dose measurement under different conditions. Results The noise effect of the photodiode increased with the the lager open field size, and decreased with the reduced distance between the photodiode and isocenter. The contribution of photodiode noise effect increase with the lager non-coplanar arc field size, with the largest up to 4.16%. As for the clinical SRT plan verification measurement, the relative difference between the SRT plan measurements and treatment planning system(TPS) before and after shielding were (1.39±1.05)% and (0.59±1.03)%, respectively (t=-5.343,P < 0.05). and for W1 vs. A16 microchamber was (1.22±1.56)% and (0.42±1.42)%, respectively (t=-5.414, P < 0.05). Conclusions The measurements of Exradin W1 are in good agreement with the TPS result and the ionization chamber measurements, but its accuracy is easily affected by the environmental radiation of radiotherapy workplace. To measure non-coplanar radiation, the photodiode should be placed as far away as possible from the isocenter and be properly shielded, which can effectively improve the accuracy and stability of the measurement and provide a strong guarantee for clinical precision radiotherapy. |
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