McManus, M;
Romano, F;
Lee, ND;
Farabolini, W;
Gilardi, A;
Royle, G;
Palmans, H;
(2020)
The challenge of ionisation chamber dosimetry in ultra-short pulsed high dose-rate Very High Energy Electron beams.
Scientific Reports
, 10
(1)
, Article 9089. 10.1038/s41598-020-65819-y.
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Abstract
High dose-rate radiotherapy, known as FLASH, has been shown to increase the differential response between healthy and tumour tissue. Moreover, Very High Energy Electrons (VHEEs) provide more favourable dose distributions than conventional radiotherapy electron and photon beams. Plane-parallel ionisation chambers are the recommended secondary standard systems for clinical reference dosimetry of electrons, therefore chamber response to these high energy and high dose-per-pulse beams must be well understood. Graphite calorimetry, the UK primary standard, has been employed to measure the dose delivered from a 200 MeV pulsed electron beam. This was compared to the charge measurements of a plane-parallel ionisation chamber to determine the absolute collection efficiency and infer the ion recombination factor. The dose-per-pulse measured by the calorimeter ranged between 0.03 Gy/pulse and 5.26 Gy/pulse, corresponding to collection efficiencies between 97% and 4%, respectively. Multiple recombination models currently available have been compared with experimental results. This work is directly applicable to the development of standard dosimetry protocols for VHEE radiotherapy, FLASH radiotherapy and other high dose-rate modalities. However, the use of secondary standard ionisation chambers for the dosimetry of high dose-per-pulse VHEEs has been shown to require large corrections for charge collection inefficiency.
| Type: | Article |
|---|---|
| Title: | The challenge of ionisation chamber dosimetry in ultra-short pulsed high dose-rate Very High Energy Electron beams |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/s41598-020-65819-y |
| Publisher version: | https://doi.org/10.1038/s41598-020-65819-y |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10101091 |
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