| DOI | Resolve DOI: https://doi.org/10.1002/mp.15425 |
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| Author | Search for: Renaud, James1; Search for: Muir, Bryan1 |
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| Affiliation | - National Research Council of Canada. Metrology Research Centre
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| Format | Text, Article |
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| Subject | dose calibration; EPID; Monte Carlo; radiochromic film; uncertainty budget |
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| Abstract | Purpose
The aim of this study is to reduce the uncertainty associated with determining dose-to-water using an amorphous silicon electronic portal imaging detector (EPID) under reference conditions by developing a direct calibration formalism based on radiochromic film measurements made within the EPID panel and detailed Monte Carlo simulations. To our knowledge, this is the first EPID-based dosimetry study reporting an uncertain budget
Methods
Pixel sensitivity and relative off-axis response were mapped by simultaneously irradiating film contained within the imager panel and acquiring an EPID image set. The detector panel was disassembled for the purpose of modeling the EPID in detail using the EGSnrc DOSXYZnrc usercode, which was in turn used to calculate dose-to-film in the EPID and dose-to-water in water conversion factors
Results
A direct comparison of the two correction methodologies investigated in this work, the previously established empirical method and the proposed simultaneous measurement approach involving in-EPID film dosimetry, produced an agreement with an RMS deviation of 1.4% overall. A combined standard relative uncertainty of 3.3% (k = 1) was estimated for the determination of absorbed dose to water at the position of the EPID using the proposed calibration methodology
Conclusions
This work describes a direct method of calibrating EPID response in terms of absorbed dose to water requiring fewer measurements than other empirical approaches, and without 2D spatial interpolation of correction factors |
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| Publication date | 2021-12-25 |
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| Publisher | American Association of Physicists in Medicine
Wiley |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 29574aa8-59c5-4cd9-a708-4034a6694e2d |
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| Record created | 2022-02-11 |
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| Record modified | 2022-02-11 |
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