X-ray beam quality checks of a magnetic resonance-guided linear accelerator with its on-board megavoltage imager

Guido C. Hilgers; Simon J. Woodings; Thomas A. Foppen; Jochem W.H. Wolthaus; Bram van Asselen; André W. Minken; Bas W. Raaymakers

doi:10.1016/j.phro.2026.100930

X-ray beam quality checks of a magnetic resonance-guided linear accelerator with its on-board megavoltage imager

Guido C. Hilgers^*
, Simon J. Woodings
, Thomas A. Foppen
, Jochem W.H. Wolthaus
, Bram van Asselen
, André W. Minken
, Bas W. Raaymakers

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

This study presents a method for fast and low-cost X-ray beam quality checks of magnetic resonance-guided radiotherapy (MRgRT) linacs using the on-board megavoltage imager (MVI). On four linacs from two clinics, beam quality was varied (quantified by ionization chamber measurements) and correlated with MVI-measured beam flatness. Both inter-linac consistency and long-term repeatability were demonstrated. The model developed for MVI-based beam quality checks was assessed in clinical practice and can be implemented on any linac of the same type for use in daily, automated dosimetry checks.

Original language	English
Article number	100930
Journal	Physics and Imaging in Radiation Oncology
Volume	37
DOIs	https://doi.org/10.1016/j.phro.2026.100930
Publication status	Published - Jan 2026

Keywords

Dosimetry
MRI-Linac
MV imager
Quality assurance
Radiotherapy
Unity

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10.1016/j.phro.2026.100930Licence: CC BY-NC-ND

X-ray beam quality checks of a magnetic resonance-guided linear accelerator with its on-board megavoltage imagerFinal published version, 1.68 MBLicence: CC BY-NC-ND

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title = "X-ray beam quality checks of a magnetic resonance-guided linear accelerator with its on-board megavoltage imager",

abstract = "This study presents a method for fast and low-cost X-ray beam quality checks of magnetic resonance-guided radiotherapy (MRgRT) linacs using the on-board megavoltage imager (MVI). On four linacs from two clinics, beam quality was varied (quantified by ionization chamber measurements) and correlated with MVI-measured beam flatness. Both inter-linac consistency and long-term repeatability were demonstrated. The model developed for MVI-based beam quality checks was assessed in clinical practice and can be implemented on any linac of the same type for use in daily, automated dosimetry checks.",

keywords = "Dosimetry, MRI-Linac, MV imager, Quality assurance, Radiotherapy, Unity",

author = "Hilgers, \{Guido C.\} and Woodings, \{Simon J.\} and Foppen, \{Thomas A.\} and Wolthaus, \{Jochem W.H.\} and \{van Asselen\}, Bram and Minken, \{Andr{\'e} W.\} and Raaymakers, \{Bas W.\}",

note = "Publisher Copyright: {\textcopyright} 2026 The Author(s). Published by Elsevier B.V. on behalf of European Society of Radiotherapy \& Oncology. This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/",

year = "2026",

month = jan,

doi = "10.1016/j.phro.2026.100930",

language = "English",

volume = "37",

journal = "Physics and Imaging in Radiation Oncology",

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T1 - X-ray beam quality checks of a magnetic resonance-guided linear accelerator with its on-board megavoltage imager

AU - Hilgers, Guido C.

AU - Woodings, Simon J.

AU - Foppen, Thomas A.

AU - Wolthaus, Jochem W.H.

AU - van Asselen, Bram

AU - Minken, André W.

AU - Raaymakers, Bas W.

N1 - Publisher Copyright: © 2026 The Author(s). Published by Elsevier B.V. on behalf of European Society of Radiotherapy & Oncology. This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/

PY - 2026/1

Y1 - 2026/1

N2 - This study presents a method for fast and low-cost X-ray beam quality checks of magnetic resonance-guided radiotherapy (MRgRT) linacs using the on-board megavoltage imager (MVI). On four linacs from two clinics, beam quality was varied (quantified by ionization chamber measurements) and correlated with MVI-measured beam flatness. Both inter-linac consistency and long-term repeatability were demonstrated. The model developed for MVI-based beam quality checks was assessed in clinical practice and can be implemented on any linac of the same type for use in daily, automated dosimetry checks.

AB - This study presents a method for fast and low-cost X-ray beam quality checks of magnetic resonance-guided radiotherapy (MRgRT) linacs using the on-board megavoltage imager (MVI). On four linacs from two clinics, beam quality was varied (quantified by ionization chamber measurements) and correlated with MVI-measured beam flatness. Both inter-linac consistency and long-term repeatability were demonstrated. The model developed for MVI-based beam quality checks was assessed in clinical practice and can be implemented on any linac of the same type for use in daily, automated dosimetry checks.

KW - Dosimetry

KW - MRI-Linac

KW - MV imager

KW - Quality assurance

KW - Radiotherapy

KW - Unity

UR - https://www.scopus.com/pages/publications/105034536343

U2 - 10.1016/j.phro.2026.100930

DO - 10.1016/j.phro.2026.100930

M3 - Article

AN - SCOPUS:105034536343

SN - 2405-6316

VL - 37

JO - Physics and Imaging in Radiation Oncology

JF - Physics and Imaging in Radiation Oncology

M1 - 100930

ER -

X-ray beam quality checks of a magnetic resonance-guided linear accelerator with its on-board megavoltage imager

Abstract

Keywords

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