Megavoltage photon FLASH for preclinical experiments

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 fie...

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Bibliographic Details
Published in:Medical physics (Lancaster) Vol. 52; no. 7; pp. e17891 - n/a
Main Authors: Taylor, Edward R. J. F., Tullis, Iain D. C., Vojnovic, Borivoj, Petersson, Kristoffer
Format: Journal Article
Language:English
Published: United States John Wiley and Sons Inc 01.07.2025
Subjects:
bremsstrahlung
Clinical Medicine
FLASH
Klinisk medicin
linac
Medical and Health Sciences
Medicin och hälsovetenskap
megavoltage
Particle Accelerators
photon
Photons - therapeutic use
Radiologi och bildbehandling
Radiology and Medical Imaging
Radiotherapy Dosage
Technical Note
tungsten
linac
photon
megavoltage
tungsten
bremsstrahlung
FLASH
ISSN:0094-2405, 2473-4209, 2473-4209
Online Access:Get full text
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Summary: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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ISSN:0094-2405
2473-4209
2473-4209
DOI:10.1002/mp.17891