Hypoxia in Mouse Intestine Induced by Electron Irradiation at High Dose-rates

Hornsey, Shirley; Bewley, D. K.

doi:10.1080/09553007114550611

Cited by 87 publications

(72 citation statements)

References 6 publications

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“…Such an extremely short delivery of radiation leads to remarkable reduction of normal tissue toxicity with respect to conventional dose-rate radiotherapy. These effects were reported five decades ago [1][2][3][4] , however translation to the clinical practice was not pursued due to lack of availability of clinically suitable radiation sources. The recent years have stimulated the revival of FLASH following the report from the Franco-Swiss team in the mouse model 5 , which has been continued in the subsequent investigations [6][7][8][9][10] .…”

mentioning

confidence: 99%

The challenge of ionisation chamber dosimetry in ultra-short pulsed high dose-rate Very High Energy Electron beams

McManus

Romano

Lee

et al. 2020

Sci Rep

101

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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. Planeparallel 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.

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mentioning

confidence: 99%

The challenge of ionisation chamber dosimetry in ultra-short pulsed high dose-rate Very High Energy Electron beams

McManus

Romano

Lee

et al. 2020

Sci Rep

101

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“…Ultra‐high dose rate irradiation (in subsecond timescales) or “FLASH” (the term coined by Favaudon et al) has recently gained attention because of the surprising observation of markedly increased therapeutic index compared to conventional dose rate irradiation (in minutes) in preclinical studies of in vivo animal models. In fact, normal tissue sparing by FLASH has been described at least as far back as 1966 by Hornsey and Alper, who attributed this finding to depletion of oxygen in tissues at very high dose rates, but in the last few decades this line of research has been relatively dormant until the recent renaissance of interest.…”

Section: For the Proposition: Peter G Maxim Phdmentioning

confidence: 99%

FLASH radiotherapy: Newsflash or flash in the pan?

Maxim

Keall

Cai³

2019

Medical Physics

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“…Adequate build-up material was used, and the dose across the foot did not vary by more than ± 2 per cent . The dosimetry was performed using collector monitors whose response was independent of dose-rate (Bewley 1971, Hornsey andBewley 1971) . The animals were anaesthetized with sodium amytal, and the toes of each foot to be irradiated were lightly held in position with Sellotape .…”

Section: Experimental Techniquesmentioning

confidence: 99%

“…Further evidence was provided by experiments with the mice breathing nitrogen, so that an anoxic response was obtained (Hornsey and Bewley 1971) .…”

Section: Introductionmentioning

confidence: 97%

Effects of Dose-rate on the Radiation Response of Rat Skin

Field

Bewley

1974

International Journal of Radiation Biology and Related Studies

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100

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Skin reactions and late deformities after irradiation of the feet of anaesthetized rats with 7 MeV electrons have been measured for dose-rates between 200 rads/min and 500 krads/min . For dose-rates up to 70 krads/min, there was no alteration in the effectiveness of the radiation, which implies that there is not a rapid form of repair of sub-lethal damage in rat skin . However, when the dose-rate was increased to 500 krads/min, there was a marked decrease in effectiveness . This observation was not made when the feet were anoxic, which implies that there is oxygen depletion at the high dose-rate . For irradiation at 500 krads/min, given in aerobic conditions, the `break-away' point occurred at about 2000 rads, above which the response of the skin was similar to that when it was made anoxic . It was concluded from this observation that the sensitive cells were at a p0 2 of 5-10 mm Hg .

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Hypoxia in Mouse Intestine Induced by Electron Irradiation at High Dose-rates

Cited by 87 publications

References 6 publications

The challenge of ionisation chamber dosimetry in ultra-short pulsed high dose-rate Very High Energy Electron beams

The challenge of ionisation chamber dosimetry in ultra-short pulsed high dose-rate Very High Energy Electron beams

FLASH radiotherapy: Newsflash or flash in the pan?

Effects of Dose-rate on the Radiation Response of Rat Skin

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