FLASH radiotherapy: Newsflash or flash in the pan?

Maxim, Peter G.; Keall, P.; Cai, Jing

doi:10.1002/mp.13685

Cited by 33 publications

(34 citation statements)

References 26 publications

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“…The dependence on the LET of the radiation used is still an unknown factor; the majority of the experiments were performed with electron beams (energy 4-6 MeV). There are significant difficulties in obtaining beams with sufficient intensity to reach the FLASH effect with X-ray [15], protons [16], and heavy ions; nevertheless, several attempts were done. The interested reader can find an exhaustive review of the state of the art in a paper recently published by Esplen et al [17].…”

Section: Introductionmentioning

confidence: 99%

FLASH Radiotherapy With Electrons: Issues Related to the Production, Monitoring, and Dosimetric Characterization of the Beam

Martino

Barca

Barone³

et al. 2020

Front. Phys.

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Various in vivo experimental works carried out on different animals and organs have shown that it is possible to reduce the damage caused to healthy tissue still preserving the therapeutic efficacy on the tumor tissue, by drastically reducing the total time of dose delivery (<200 ms). This effect, called the FLASH effect, immediately attracted considerable attention within the radiotherapy community, due to the possibility of widening the therapeutic window and treating effectively tumors which appear radioresistant to conventional techniques. Despite the experimental evidence, the radiobiological mechanisms underlying the FLASH effect and the beam parameters contributing to its optimization are not yet known in details. In order to fully understand the FLASH effect, it might be worthy to investigate some alternatives which can further improve the tools adopted so far, in terms of both linac technology and dosimetric systems. This work investigates the problems and solutions concerning the realization of an electron accelerator dedicated to FLASH therapy and optimized for in vivo experiments. Moreover, the work discusses the saturation problems of the most common radiotherapy dosimeters when used in the very high dose-per-pulse FLASH conditions and provides some preliminary experimental data on their behavior.

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Section: Introductionmentioning

confidence: 99%

FLASH Radiotherapy With Electrons: Issues Related to the Production, Monitoring, and Dosimetric Characterization of the Beam

Martino

Barca

Barone³

et al. 2020

Front. Phys.

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“…7 These papers were met with vigorous editorial commentary and debate. [8][9][10][11][12][13] The mechanism of FLASH radiation therapy in sparing normal tissues is not well understood and is still under intense investigation. A series of hypotheses has been proposed based on fundamental principles of radiation physics and chemistry, and tumor vs normal cell redox metabolism.…”

Section: Introductionmentioning

confidence: 99%

“…The feasibility of treatment of a first human patient with FLASH dose rates was demonstrated recently 7 . These papers were met with vigorous editorial commentary and debate 8–13 …”

Section: Introductionmentioning

confidence: 99%

Feasibility of proton FLASH irradiation using a synchrocyclotron for preclinical studies

et al. 2020

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It has been recently shown that radiotherapy at ultrahigh dose rates (>40 Gy/s, FLASH) has a potential advantage in sparing healthy organs compared to that at conventional dose rates. The purpose of this work is to show the feasibility of proton FLASH irradiation using a gantry-mounted synchrocyclotron as a first step toward implementing an experimental setup for preclinical studies. Methods: A clinical Mevion HYPERSCAN â synchrocyclotron was modified to deliver ultrahigh dose rates. Pulse widths of protons with 230 MeV energy were manipulated from 1 to 20 ls to deliver in conventional and ultrahigh dose rate. A boron carbide absorber was placed in the beam for range modulation. A Faraday cup was used to determine the number of protons per pulse at various dose rates. Dose rate was determined by the dose measured with a plane-parallel ionization chamber with respect to the actual delivery time. The integral depth dose (IDD) was measured with a Bragg ionization chamber. Monte Carlo simulation was performed in TOPAS as the secondary check for the measurements. Results: Maximum protons charge per pulse, measured with the Faraday cup, was 54.6 pC at 20 ls pulse width. The measured IDD agreed well with the Monte Carlo simulation. The average dose rate measured using the ionization chamber showed 101 Gy/s at the entrance and 216 Gy/s at the Bragg peak with a full width at half maximum field size of 1.2 cm. Conclusions: It is feasible to deliver protons at 100 and 200 Gy/s average dose rate at the plateau and the Bragg peak, respectively, in a small~1 cm 2 field using a gantry-mounted synchrocyclotron.

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“…The concept of PHASER [38] is particularly interesting, but its feasibility remains extremely challenging both from the clinical and the technological point of view. Clinical difficulties related to "FLASH IMRT" are discussed in [40]; furthermore, the generation of a X-ray beam capable of reaching FLASH dose rate requires at least four times the electron current needed for linac working in electron mode [refer to NIST data [41] for Bremsstrahlung efficiency]. On the other hand, the effective implementation of FLASH with proton is feasible, even though it also poses several technological issues.…”

Section: Discussionmentioning

confidence: 99%

Transforming an IORT Linac Into a FLASH Research Machine: Procedure and Dosimetric Characterization

Felici¹,

Barca

Barone³

et al. 2020

Front. Phys.

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FLASH radiotherapy: Newsflash or flash in the pan?

Cited by 33 publications

References 26 publications

FLASH Radiotherapy With Electrons: Issues Related to the Production, Monitoring, and Dosimetric Characterization of the Beam

FLASH Radiotherapy With Electrons: Issues Related to the Production, Monitoring, and Dosimetric Characterization of the Beam

Feasibility of proton FLASH irradiation using a synchrocyclotron for preclinical studies

Transforming an IORT Linac Into a FLASH Research Machine: Procedure and Dosimetric Characterization

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