Absorbed dose-to-water protocol applied to synchrotron-generated x-rays at very high dose rates

The development of innovative approaches that would reduce the sensitivity of healthy tissues to irradiation while maintaining the efficacy of the treatment on the tumor is of crucial importance for the progress of the efficacy of radiotherapy. Recent methodological developments and innovations, such as scanned beams, ultra-high dose rates, and very high-energy electrons, which may be simultaneously available on new accelerators, would allow for possible radiobiological advantages of very short pulses of ultra-high dose rate (FLASH) therapy for radiation therapy to be considered. In particular, very high-energy electron (VHEE) radiotherapy, in the energy range of 100 to 250 MeV, first proposed in the 2000s, would be particularly interesting both from a ballistic and biological point of view for the establishment of this new type of irradiation technique. In this review, we examine and summarize the current knowledge on VHEE radiotherapy and provide a synthesis of the studies that have been published on various experimental and simulation works. We will also consider the potential for VHEE therapy to be translated into clinical contexts.

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SU-E-T-117: Absorbed Dose to Water Measurement with a Sandwich Method for High Dose-Rate Ir-192 Brachytherapy Sources

Medical Physics ◽

10.1118/1.3612068 ◽

2011 ◽

Vol 38 (6Part12) ◽

pp. 3513-3513

Author(s):

F Araki ◽

F Yoshiyama ◽

T Ohno ◽

K Kakei ◽

J Wulff

Keyword(s):

Dose Rate ◽

Absorbed Dose ◽

High Dose Rate ◽

High Dose ◽

Sandwich Method ◽

Absorbed Dose To Water ◽

Water Measurement

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The radiation chemistry of carbon monoxide at very high dose rates

Canadian Journal of Chemistry ◽

10.1139/v70-511 ◽

1970 ◽

Vol 48 (19) ◽

pp. 3029-3033 ◽

Cited By ~ 3

Author(s):

C. Willis ◽

O. A. Miller

Keyword(s):

Carbon Dioxide ◽

Carbon Monoxide ◽

Excited State ◽

Oxygen Atom ◽

Dose Rate ◽

Electron Accelerator ◽

Radiation Chemistry ◽

High Dose ◽

Dose Rates ◽

Very High

Carbon monoxide has been irradiated with single intense pulses from an electron accelerator at a dose rate of ~ 2 × 1027 eV g−1 s−1. The yield of carbon dioxide obtained was G(CO2) = 0.7 ± 0.1 with a very small yield of carbon suboxide, G(C3O2) ≤ 0.02.Addition of propene reduces the carbon dioxide yield to almost zero while addition of propane has no effect. This suggests that propene is acting as an oxygen atom scavenger rather than as a quencher of an excited state of carbon monoxide. However, rate constant data do not support this suggestion and it is concluded that the residual yield of carbon dioxide observed at high dose rates arises from reaction 9[Formula: see text]where CO+ is in an A2Π or B2Σ+ state.

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The new NMi orthovolt x-rays absorbed dose to water primary standard based on water calorimetry

Physics in Medicine and Biology ◽

10.1088/0031-9155/53/13/009 ◽

2008 ◽

Vol 53 (13) ◽

pp. 3531-3542 ◽

Cited By ~ 15

Author(s):

L A de Prez ◽

J A de Pooter

Keyword(s):

Primary Standard ◽

Absorbed Dose ◽

X Rays ◽

Absorbed Dose To Water

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Nanoparticles synthesis by electron beam radiolysis

Open Chemistry ◽

10.2478/s11532-014-0502-x ◽

2014 ◽

Vol 12 (7) ◽

pp. 774-781 ◽

Cited By ~ 5

Author(s):

Ioan Călinescu ◽

Diana Martin ◽

Daniel Ighigeanu ◽

Adina Gavrila ◽

Adrian Trifan ◽

...

Keyword(s):

Silver Nanoparticles ◽

Electron Beam ◽

Chemical Reduction ◽

Absorbed Dose ◽

Reduction Process ◽

High Dose Rate ◽

High Dose ◽

Experimental Conditions ◽

Dose Rates ◽

Absorbed Dose Rates

AbstractElectron beam (EB) irradiation is a useful method to generate stable silver nanoparticles without the interference of inherent impurities generated from chemical reactions. Our experiments were carried out using linear electron beam accelerators with two different EB absorbed dose rates: 2 kGy min−1 and 7–8 kGy s−1, and with different absorbed dose levels. The optimum conditions for silver nanoparticles (AgNPs) generation by radiolysis, or by radiolysis combined with chemical reduction, were established. In order to obtain a good yield for AgNPs synthesized by radiolysis, a high dose rate is required, resulting in a rapid production process. At low absorbed dose rates, the utilization of a stabilization agent is advisable. By modifying the experimental conditions, the ratio between the chemical and radiolytic reduction process can be adjusted, thus it is possible to obtain nanoparticles with tailored characteristics, depending on the desired application.

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Feasibility Study of a Prostate Cancer FLASH Therapy Treatment With Electrons of High Energy

10.21203/rs.3.rs-156237/v1 ◽

2021 ◽

Author(s):

Alessio Sarti ◽

Patrizia De Maria ◽

Battistoni Giuseppe ◽

Micol De Simoni ◽

Cinzia Di Felice ◽

...

Keyword(s):

Prostate Cancer ◽

Technological Development ◽

High Energy ◽

Planning System ◽

Treatment Planning System ◽

High Dose ◽

Dose Rates ◽

Very High Energy ◽

Almost All ◽

Very High

Abstract Prostate cancer is among the most common cancers in men and one of the leading causes of death worldwide. Different therapies are adopted for its treatment and generally radiotherapy with photons (RT) is the preferred solution in almost all cases. Up to now, in addition to photons, only protons have been implemented as alternative radiotherapy. The use of Very High Energy Electron (VHEE) beams (100-200 MeV) has been suggested in literature but the needed accelerators are more demanding, as far as space and cost are concerned, with respect to standard photon devices, with only limited advantages when compared to protons or other heavy ions. In this contribution we investigate how recent developments in electron beam therapy could reshape the landscape of prostate treatments. The VHEE Treatment Planning System obtained combining an accurate Monte Carlo (MC) simulation with a simple modelling of the FLASH effect (healthy tissues sparing at very high dose rates) is compared with conventional RT. The results demonstrate that FLASH therapy with VHEE beams of 70-130 MeV could represent a valid alternative to standard RT allowing a better sparing of the healthy tissues surrounding the tumour, in the framework of an affordable technological development.

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Generation of ultrafast, transient, highly acidic pH spikes in the radiolysis of water at very high dose rates. Relevance for FLASH radiotherapy.

Canadian Journal of Chemistry ◽

10.1139/cjc-2021-0259 ◽

2021 ◽

Author(s):

Abida Sultana ◽

Ahmed Alanazi ◽

Jintana Meesungnoen ◽

Jean-Paul Jay-Gerin

Keyword(s):

High Dose ◽

Acidic Ph ◽

Cellular Functions ◽

Spike Response ◽

Dose Rates ◽

Hydronium Ions ◽

Circular Surface ◽

Sparing Effect ◽

Tissue Sparing ◽

Very High

Monte Carlo multi-track chemistry simulations were carried out to study the effects of high dose rates on the transient yields of hydronium ions (H3O+) formed during low linear energy transfer (LET) radiolysis of both pure, deaerated and aerated liquid water at 25 °C, in the interval ~1 ps–10 μs. Our simulation model consisted of randomly irradiating water with N interactive tracks of 300-MeV incident protons (LET ~ 0.3 keV/μm), which simultaneously impact perpendicularly on the water within a circular surface. The effect of the dose rate was studied by varying N. Our calculations showed that the radiolytic formation of H3O+ causes the entire irradiated volume to temporarily become very acidic. The magnitude and duration of this abrupt “acid-spike” response depend on the value of N. It is most intense at times less than ~10–100 ns, equal to ~3.4 and 2.8 for N = 500 and 2000 (i.e., for dose rates of ~1.9 × 109 and 8.7 × 109 Gy/s, respectively). At longer times, the pH gradually increases for all N values and eventually returns to the neutral value of seven, which corresponds to the non-radiolytic, pre-irradiation concentration of H3O+. It is worth noting that these early acidic pH responses are very little dependent on the presence or absence of oxygen. Finally, given the importance of pH for many cellular functions, this study suggests that these acidic pH spikes may contribute to the normal tissue-sparing effect of FLASH radiotherapy.

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