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High dose-per-pulse electron beam dosimetry : Commissioning of the Oriatron eRT6 prototype linear accelerator for preclinical use: Commissioning

Jaccard, Maud ; Durán, Maria Teresa ; Petersson, Kristoffer LU ; Germond, Jean François ; Liger, Philippe ; Vozenin, Marie Catherine ; Bourhis, Jean ; Bochud, François and Bailat, Claude (2018) In Medical Physics 45(2). p.863-874
Abstract

Purpose: The Oriatron eRT6 is an experimental high dose-per-pulse linear accelerator (linac) which was designed to deliver an electron beam with variable dose-rates, ranging from a few Gy/min up to hundreds of Gy/s. It was built to study the radiobiological effects of high dose-per-pulse/dose-rate electron beam irradiation, in the context of preclinical and cognitive studies. In this work, we report on the commissioning and beam monitoring of the Oriatron eRT6 prototype linac. Materials and Methods: The beam was characterized in different steps. The output stability was studied by performing repeated measurements over a period of 20 months. The relative output variations caused by changing beam parameters, such as the temporal electron... (More)

Purpose: The Oriatron eRT6 is an experimental high dose-per-pulse linear accelerator (linac) which was designed to deliver an electron beam with variable dose-rates, ranging from a few Gy/min up to hundreds of Gy/s. It was built to study the radiobiological effects of high dose-per-pulse/dose-rate electron beam irradiation, in the context of preclinical and cognitive studies. In this work, we report on the commissioning and beam monitoring of the Oriatron eRT6 prototype linac. Materials and Methods: The beam was characterized in different steps. The output stability was studied by performing repeated measurements over a period of 20 months. The relative output variations caused by changing beam parameters, such as the temporal electron pulse width, the pulse repetition frequency and the pulse amplitude were also analyzed. Finally, depth dose curves and field sizes were measured for two different beam settings, resulting in one beam with a conventional radiotherapy dose-rate and one with a much higher dose-rate. Measurements were performed with Gafchromic EBT3 films and with a PTW Advanced Markus ionization chamber. In addition, we developed a beam current monitoring system based on the signals from an induction torus positioned at the beam exit of the waveguide and from a graphite beam collimator. Results: The stability of the output over repeated measurements was found to be good, with a standard deviation smaller than 1%. However, non-negligible day-to-day variations of the beam output were observed. Those output variations showed different trends depending on the dose-rate. The analysis of the relative output variation as a function of various beam parameters showed that in a given configuration, the dose-rate could be reliably varied over three orders of magnitude. Interdependence effects on the output variation between the parameters were also observed. The beam energy and field size were found to be slightly dose-rate-dependent and suitable mainly for small animal irradiation. The beam monitoring system was able to measure in a reproducible way the total charge of electrons that exit the machine, as long as the electron pulse amplitude remains above a given threshold. Furthermore, we were able to relate the charge measured with the monitoring system to the absorbed dose in a solid water phantom. Conclusion: The Oriatron eRT6 was successfully commissioned for preclinical use and is currently in full operation, with studies being performed on the radiobiological effects of high dose-per-pulse irradiation.

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author
; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
beam monitoring, commissioning, high dose-per-pulse, high dose-rate, linac
in
Medical Physics
volume
45
issue
2
pages
863 - 874
publisher
American Association of Physicists in Medicine
external identifiers
  • scopus:85040041610
  • pmid:29206287
ISSN
0094-2405
DOI
10.1002/mp.12713
language
English
LU publication?
no
additional info
Publisher Copyright: © 2017 American Association of Physicists in Medicine.
id
74f86033-7dfa-4d88-83c3-4edf61664782
date added to LUP
2021-11-03 18:16:11
date last changed
2024-06-29 21:18:00
@article{74f86033-7dfa-4d88-83c3-4edf61664782,
  abstract     = {{<p>Purpose: The Oriatron eRT6 is an experimental high dose-per-pulse linear accelerator (linac) which was designed to deliver an electron beam with variable dose-rates, ranging from a few Gy/min up to hundreds of Gy/s. It was built to study the radiobiological effects of high dose-per-pulse/dose-rate electron beam irradiation, in the context of preclinical and cognitive studies. In this work, we report on the commissioning and beam monitoring of the Oriatron eRT6 prototype linac. Materials and Methods: The beam was characterized in different steps. The output stability was studied by performing repeated measurements over a period of 20 months. The relative output variations caused by changing beam parameters, such as the temporal electron pulse width, the pulse repetition frequency and the pulse amplitude were also analyzed. Finally, depth dose curves and field sizes were measured for two different beam settings, resulting in one beam with a conventional radiotherapy dose-rate and one with a much higher dose-rate. Measurements were performed with Gafchromic EBT3 films and with a PTW Advanced Markus ionization chamber. In addition, we developed a beam current monitoring system based on the signals from an induction torus positioned at the beam exit of the waveguide and from a graphite beam collimator. Results: The stability of the output over repeated measurements was found to be good, with a standard deviation smaller than 1%. However, non-negligible day-to-day variations of the beam output were observed. Those output variations showed different trends depending on the dose-rate. The analysis of the relative output variation as a function of various beam parameters showed that in a given configuration, the dose-rate could be reliably varied over three orders of magnitude. Interdependence effects on the output variation between the parameters were also observed. The beam energy and field size were found to be slightly dose-rate-dependent and suitable mainly for small animal irradiation. The beam monitoring system was able to measure in a reproducible way the total charge of electrons that exit the machine, as long as the electron pulse amplitude remains above a given threshold. Furthermore, we were able to relate the charge measured with the monitoring system to the absorbed dose in a solid water phantom. Conclusion: The Oriatron eRT6 was successfully commissioned for preclinical use and is currently in full operation, with studies being performed on the radiobiological effects of high dose-per-pulse irradiation.</p>}},
  author       = {{Jaccard, Maud and Durán, Maria Teresa and Petersson, Kristoffer and Germond, Jean François and Liger, Philippe and Vozenin, Marie Catherine and Bourhis, Jean and Bochud, François and Bailat, Claude}},
  issn         = {{0094-2405}},
  keywords     = {{beam monitoring; commissioning; high dose-per-pulse; high dose-rate; linac}},
  language     = {{eng}},
  number       = {{2}},
  pages        = {{863--874}},
  publisher    = {{American Association of Physicists in Medicine}},
  series       = {{Medical Physics}},
  title        = {{High dose-per-pulse electron beam dosimetry : Commissioning of the Oriatron eRT6 prototype linear accelerator for preclinical use: Commissioning}},
  url          = {{http://dx.doi.org/10.1002/mp.12713}},
  doi          = {{10.1002/mp.12713}},
  volume       = {{45}},
  year         = {{2018}},
}