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Title: Quality assurance of geometric accuracy based on an electronic portal imaging device and log data analysis for Dynamic WaveArc irradiation
Authors: Hirashima, Hideaki  kyouindb  KAKEN_id  orcid (unconfirmed)
Miyabe, Yuki  kyouindb  KAKEN_id
Nakamura, Mitsuhiro  kyouindb  KAKEN_id
Mukumoto, Nobutaka  kyouindb  KAKEN_id
Mizowaki, Takashi  kyouindb  KAKEN_id  orcid (unconfirmed)
Hiraoka, Masahiro
Author's alias: 平島, 英明
宮部, 結城
中村, 光宏
椋本, 宜学
溝脇, 尚志
平岡, 眞寛
Keywords: Dynamic WaveArc
electronic portal imaging device
log data
quality assurance
Issue Date: May-2018
Publisher: Wiley
Journal title: Journal of Applied Clinical Medical Physics
Volume: 19
Issue: 3
Start page: 234
End page: 242
Abstract: The purpose of this study was to develop a simple verification method for the routine quality assurance (QA) of Dynamic WaveArc (DWA) irradiation using electronic portal imaging device (EPID) images and log data analysis. First, an automatic calibration method utilizing the outermost multileaf collimator (MLC) slits was developed to correct the misalignment between the center of the EPID and the beam axis. Moreover, to verify the detection accuracy of the MLC position according to the EPID images, various positions of the MLC with intentional errors in the range 0.1–1 mm were assessed. Second, to validate the geometric accuracy during DWA irradiation, tests were designed in consideration of three indices. Test 1 evaluated the accuracy of the MLC position. Test 2 assessed dose output consistency with variable dose rate (160–400 MU/min), gantry speed (2.2–6°/s), and ring speed (0.5–2.7°/s). Test 3 validated dose output consistency with variable values of the above parameters plus MLC speed (1.6–4.2 cm/s). All tests were delivered to the EPID and compared with those obtained using a stationary radiation beam with a 0° gantry angle. Irradiation log data were recorded simultaneously. The 0.1‐mm intentional error on the MLC position could be detected by the EPID, which is smaller than the EPID pixel size. In Test 1, the MLC slit widths agreed within 0.20 mm of their exposed values. The averaged root‐mean‐square error (RMSE) of the dose outputs was less than 0.8% in Test 2 and Test 3. Using log data analysis in Test 3, the RMSE between the planned and recorded data was 0.1 mm, 0.12°, and 0.07° for the MLC position, gantry angle, and ring angle, respectively. The proposed method is useful for routine QA of the accuracy of DWA.
Rights: © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
DOI(Published Version): 10.1002/acm2.12324
PubMed ID: 29633542
Appears in Collections:Journal Articles

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