| Download | - View final version: Electron beam reference dosimetry measurements obtained at multiple institutions using the Addendum to AAPM's TG-51 protocol (PDF, 1.6 MiB)
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| DOI | Resolve DOI: https://doi.org/10.1002/mp.17802 |
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| Author | Search for: Muir, Bryan R. Muir1ORCID identifier: https://orcid.org/0000-0001-9310-9686; Search for: Davis, Thomas H.; Search for: Dhanesar, Sandeep; Search for: Hillman, Yair; Search for: Iakovenko, Viktor; Search for: Lei, Yu; Search for: Pike, Tina; Search for: Pinkham, Daniel W.; Search for: Vandervoort, Eric; Search for: Kim, Grace Gwe-Ya |
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| Affiliation | - National Research Council Canada. Metrology Research Centre
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| Format | Text, Article |
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| Subject | TG-51; Addendum; reference dosimetry |
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| Abstract | Background: The TG-51 protocol describes methods for obtaining referencedosimetry measurements for external photon and electron beams. Since thepublication of TG-51 in 1999, research on reference dosimetry has allowedrevisiting the procedures and data recommended in the protocol. An Adden-dum to TG-51 for electron beam reference dosimetry was published in 2024,which revises the formalism and procedures and provides updated kQ data.
Purpose: To compare clinical reference dosimetry measurements in elec-tron beams obtained using the original American Association of Physicistsin Medicine’s (AAPM) TG-51 protocol and its associated Addendum (AAPMWGTG51 report 385).
Methods: Measurements were performed in electron beams using the data andmethods prescribed by TG-51 and its Addendum. Nine participants (eight clin-ics and one primary standards laboratory) provided data and measurements. Results were obtained with 18 linacs using 87 total beam energies (4–6 ener-gies per linac) between 4–22 MeV, representing the range of electron beamenergies used clinically. Various cylindrical (6 types) and parallel-plate (4 types)ionization chamber types were employed, representing most of the chamberscommonly used in modern radiation therapy clinics. An analysis was performedto determine if differences arise from the new data recommended for beamquality conversion factors or from changes to the procedure.
Results: Results for dose to water per monitor unit obtained using the Adden-dum are up to 2.3% higher in low-energy beams and 1.3% higher in high-energybeams compared to results obtained using the original TG-51 protocol. Thesedifferences are consistent with what was predicted by the Addendum. Differ-ences arise from both the changes to procedure (up to 0.7% from not requiringthe PQgᵣ correction for cylindrical chambers, 0.5% from the change in the shiftof the point of measurement for parallel-plate chambers) as well as the recom-mended data (0.8% from differences in k′R₅₀' 0.5% from differences in kₑcₐₗ).
Conclusion: This work elucidates where differences arise in results obtainedusing the original TG-51 protocol and its associated Addendum for electronbeam reference dosimetry. The results presented here provide confidence in the new approach and data recommended by the Addendum. Clinical physi-cists can use these results to ensure that differences are as expected whenimplementing the Addendum. |
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| Publication date | 2025-04-03 |
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| Publisher | American Association of Physicistsin Medicine
Wiley |
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| Licence | |
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| In | |
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| Language | English |
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| In press | Yes |
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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 | b8b3b894-36a5-4766-a555-56c1af2a0972 |
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| Record created | 2025-05-01 |
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| Record modified | 2025-05-01 |
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