Megavoltage photon FLASH for preclinical experiments
(2025) In Medical Physics 52(7).- Abstract
Background: FLASH radiotherapy using megavoltage (MV) photon beams should enable greater therapeutic efficacy, target deep seated tumors, and provide insights into mechanisms within FLASH. Purpose: In this study, we aim to show how to facilitate ultra-high dose rates (FLASH) with MV photons over a field size of 12–15 mm, using a 6 MeV (nominal) preclinical electron linear accelerator (linac). Our intention is to utilize this setup to deliver FLASH with MV photons in future preclinical experiments. Methods: An electron linear accelerator operating at a pulse repetition frequency of 300 Hz, a tungsten target, and a beam hardening filter were used, in conjunction with beam tuning and source-to-surface distance (SSD) reduction. Depth dose... (More)
Background: FLASH radiotherapy using megavoltage (MV) photon beams should enable greater therapeutic efficacy, target deep seated tumors, and provide insights into mechanisms within FLASH. Purpose: In this study, we aim to show how to facilitate ultra-high dose rates (FLASH) with MV photons over a field size of 12–15 mm, using a 6 MeV (nominal) preclinical electron linear accelerator (linac). Our intention is to utilize this setup to deliver FLASH with MV photons in future preclinical experiments. Methods: An electron linear accelerator operating at a pulse repetition frequency of 300 Hz, a tungsten target, and a beam hardening filter were used, in conjunction with beam tuning and source-to-surface distance (SSD) reduction. Depth dose curves, beam profiles, and average dose rates were determined using EBT-XD Gafchromic film, and an Advanced Markus ionization chamber was used to measure the photon charge output. Results: A 0.55 mm thick tungsten target, in combination with a 6 mm thick copper hardening filter were found to produce photon FLASH dose rates, with minimal electron contamination, delivering dose rates > 40 Gy/s over fields of 12–15 mm. Beam flatness and symmetry were comparable in horizontal and vertical planes. Conclusion: Ultra-high average dose rate beams have been achieved with MV photons for preclinical irradiation fields, enabling future preclinical FLASH radiation experiments.
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- author
- Taylor, Edward R.J.F. ; Tullis, Iain D.C. ; Vojnovic, Borivoj and Petersson, Kristoffer LU
- organization
- publishing date
- 2025-07
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- bremsstrahlung, FLASH, linac, megavoltage, photon, tungsten
- in
- Medical Physics
- volume
- 52
- issue
- 7
- article number
- e17891
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- pmid:40387520
- scopus:105005585792
- ISSN
- 0094-2405
- DOI
- 10.1002/mp.17891
- language
- English
- LU publication?
- yes
- id
- 3721ecbd-92f2-4bad-ae64-67648f9aa889
- date added to LUP
- 2025-09-18 13:20:50
- date last changed
- 2025-10-16 17:13:01
@article{3721ecbd-92f2-4bad-ae64-67648f9aa889,
abstract = {{<p>Background: FLASH radiotherapy using megavoltage (MV) photon beams should enable greater therapeutic efficacy, target deep seated tumors, and provide insights into mechanisms within FLASH. Purpose: In this study, we aim to show how to facilitate ultra-high dose rates (FLASH) with MV photons over a field size of 12–15 mm, using a 6 MeV (nominal) preclinical electron linear accelerator (linac). Our intention is to utilize this setup to deliver FLASH with MV photons in future preclinical experiments. Methods: An electron linear accelerator operating at a pulse repetition frequency of 300 Hz, a tungsten target, and a beam hardening filter were used, in conjunction with beam tuning and source-to-surface distance (SSD) reduction. Depth dose curves, beam profiles, and average dose rates were determined using EBT-XD Gafchromic film, and an Advanced Markus ionization chamber was used to measure the photon charge output. Results: A 0.55 mm thick tungsten target, in combination with a 6 mm thick copper hardening filter were found to produce photon FLASH dose rates, with minimal electron contamination, delivering dose rates > 40 Gy/s over fields of 12–15 mm. Beam flatness and symmetry were comparable in horizontal and vertical planes. Conclusion: Ultra-high average dose rate beams have been achieved with MV photons for preclinical irradiation fields, enabling future preclinical FLASH radiation experiments.</p>}},
author = {{Taylor, Edward R.J.F. and Tullis, Iain D.C. and Vojnovic, Borivoj and Petersson, Kristoffer}},
issn = {{0094-2405}},
keywords = {{bremsstrahlung; FLASH; linac; megavoltage; photon; tungsten}},
language = {{eng}},
number = {{7}},
publisher = {{John Wiley & Sons Inc.}},
series = {{Medical Physics}},
title = {{Megavoltage photon FLASH for preclinical experiments}},
url = {{http://dx.doi.org/10.1002/mp.17891}},
doi = {{10.1002/mp.17891}},
volume = {{52}},
year = {{2025}},
}