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Okazaki Y, Kusumoto T, Roux S, Hirayama R, Fromm M, Bazzi R, Kodaira S, Kataoka J. Increase of OH radical yields due to the decomposition of hydrogen peroxide by gold nanoparticles under X-ray irradiation. RSC Adv 2024; 14:9509-9513. [PMID: 38516151 PMCID: PMC10953845 DOI: 10.1039/d4ra00208c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/14/2024] [Indexed: 03/23/2024] Open
Abstract
We elucidate the decomposition mechanism of hydrogen peroxide, which is formed by water radiolysis, by gold nanoparticles (GNPs) under X-ray irradiation. The variations in yields of hydrogen peroxide generated in the presence of GNPs are evaluated using the Ghormley technique. The increase of yields of OH radicals has been quantified using Ampliflu® Red solutions. Almost all hydrogen peroxide generated by irradiation of <25 Gy is decomposed by GNPs, while the yield of OH radicals increases by 1.6 times. The amount of OH radicals thus obtained is almost equivalent to that of the decomposed hydrogen peroxide. The decomposition of hydrogen peroxide is an essential reaction to produce additional OH radicals efficiently in the vicinity of GNPs.
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Affiliation(s)
- Yu Okazaki
- Graduate School of Advanced Science and Engineering, Waseda University 3-4-1 Okubo, Shinjuku-ku Tokyo 169-8555 Japan
| | - Tamon Kusumoto
- National Institutes for Quantum Science and Technology (QST) 4-9-1 Anagawa, Inage-ku Chiba 263-8555 Japan
| | - Stephane Roux
- UMR CNRS 6249 Chrono-Environnement, Université de Franche-Comté F-25030 Besançon Cedex France
| | - Ryoichi Hirayama
- National Institutes for Quantum Science and Technology (QST) 4-9-1 Anagawa, Inage-ku Chiba 263-8555 Japan
| | - Michel Fromm
- UMR CNRS 6249 Chrono-Environnement, Université de Franche-Comté F-25030 Besançon Cedex France
| | - Rana Bazzi
- UMR CNRS 6249 Chrono-Environnement, Université de Franche-Comté F-25030 Besançon Cedex France
| | - Satoshi Kodaira
- National Institutes for Quantum Science and Technology (QST) 4-9-1 Anagawa, Inage-ku Chiba 263-8555 Japan
| | - Jun Kataoka
- Graduate School of Advanced Science and Engineering, Waseda University 3-4-1 Okubo, Shinjuku-ku Tokyo 169-8555 Japan
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2
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Audouin J, Hofverberg P, Ngono-Ravache Y, Desorgher L, Baldacchino G. Intermediate LET-like effect in distal part of proton Bragg peak revealed by track-ends imaging during super-Fricke radiolysis. Sci Rep 2023; 13:15460. [PMID: 37726376 PMCID: PMC10509149 DOI: 10.1038/s41598-023-42639-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 09/13/2023] [Indexed: 09/21/2023] Open
Abstract
Upstream of the efficiency of proton or carbon ion beams in cancer therapy, and to optimize hadrontherapy results, we analysed the chemistry of Fricke solutions in track-end of 64-MeV protons and 1.14-GeV carbon ions. An original optical setup is designed to determine the primary track-segment yields along the last millimetres of the ion track with a sub-millimetre resolution. The Fe3+-yield falls in the Bragg peak to (4.9 ± 0.4) × 10-7 mol/J and 1.9 × 10-7 mol/J, under protons and carbon ions respectively. Beyond the Bragg peak, a yield recovery is observed over 1 mm for proton beams. It is attributed to the intermediate-LET of protons in this region where their energy decreases and energy distribution becomes broader, in relation with the longitudinal straggling of the beam. Consequently to this LET decrease in the distal part of the Bragg peak, Fe3+-yield increases. For the first time, this signature is highlighted at the chemical level under proton irradiation. Nevertheless, this phenomenon is not identified for carbon ion beams since their straggling is lower. It would need a greater spatial resolution to be observed.
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Affiliation(s)
- J Audouin
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191, Gif-sur-Yvette, France
| | | | - Y Ngono-Ravache
- CIMAP, CEA-CNRS-ENSICAEN-UNICAEN, Normandy University, Cedex 04, 14050, Caen, France
| | - L Desorgher
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007, Lausanne, Switzerland
| | - G Baldacchino
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191, Gif-sur-Yvette, France.
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3
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Kusumoto T, Inaniwa T, Mizushima K, Sato S, Hojo S, Kitamura H, Konishi T, Kodaira S. Radiation Chemical Yields of 7-Hydroxy-Coumarin-3-Carboxylic Acid for Proton- and Carbon-Ion Beams at Ultra-High Dose Rates: Potential Roles in FLASH Effects. Radiat Res 2022; 198:255-262. [PMID: 35738014 DOI: 10.1667/rade-21-00.230.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 06/06/2022] [Indexed: 11/03/2022]
Abstract
It has been observed that healthy tissues are spared at ultra-high dose rate (UHDR: >40 Gy/s), so called FLASH effect. To elucidate the mechanism of FLASH effect, we evaluate changes in radiation chemical yield (G value) of 7-hydroxy-coumarin-3-carboxylic acid (7OH-C3CA), which is formed by the reaction of hydroxyl radicals with coumarin-3-carboxylic acid (C3CA), under carbon ions (140 MeV/u) and protons (27.5 and 55 MeV) in a wide-dose-rate range up to 100 Gy/s. The relative G value, which is the G value at each dose rate normalized by that at the conventional dose (CONV: 0.1 Gy/s >), 140 MeV/u carbon-ion beam is almost equivalent to 27.5 and 55 MeV proton beams. This finding implies that UHDR irradiations using carbon-ion beams have a potential to spare healthy tissues. Furthermore, we evaluate the G value of 7OH-C3CA under the de-oxygenated condition to investigate roles of oxygen to the generation of 7OH-C3CA effect. The G value of 7OH-C3CA under the de-oxygenated condition is lower than that under the oxygenated condition. The G value of 7OH-C3CA under the de-oxygenated condition is higher than those under UHDR irradiations. By direct measurements of the oxygen concentration during 55 MeV proton irradiations, the oxygen concentration drops by 0.1%/Gy, which is independent of the dose rate. When the oxygen concentration directly affects to yields of 7OH-C3CA, the rate of decrease in the oxygen concentration may be correlated with that of decrease in the G value of 7OH-C3CA. However, the reduction rate of G value under UHDR is significantly higher than the oxygen consumption. This finding implied that the influence of the reaction between water radiolysis species formed by neighborhood tracks could be strongly related to the mechanisms of UHDR effect.
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Affiliation(s)
- Tamon Kusumoto
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Taku Inaniwa
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Kota Mizushima
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Shinji Sato
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Satoru Hojo
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Hisashi Kitamura
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Teruaki Konishi
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Satoshi Kodaira
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
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4
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Estimation of biological effect of Cu-64 radiopharmaceuticals with Geant4-DNA simulation. Sci Rep 2022; 12:8957. [PMID: 35624130 PMCID: PMC9142517 DOI: 10.1038/s41598-022-13096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 05/05/2022] [Indexed: 11/24/2022] Open
Abstract
The aim of this work is to estimate the biological effect of targeted radionuclide therapy using Cu-64, which is a well-known Auger electron emitter. To do so, we evaluate the absorbed dose of emitted particles from Cu-64 using the Geant4-DNA Monte Carlo simulation toolkit. The contribution of beta particles to the absorbed dose is higher than that of Auger electrons. The simulation result agrees with experimental ones evaluated using coumarin-3-carboxylic acid chemical dosimeter. The simulation result is also in good agreement with previous ones obtained using fluorescent nuclear track detector. From the results of present simulation (i.e., absorbed dose estimation) and previous biological experiments using two cell lines (i.e., evaluation of survival curves), we have estimated the relative biological effectiveness (RBE) of Cu-64 emitted particles on CHO wild-type cells and xrs5 cells. The RBE of xrs5 cells exposed to Cu-64 is almost equivalent to that with gamma rays and protons and C ions. This result indicates that the radiosensitivity of xrs5 cells is independent of LET. In comparison to this, the RBE on CHO wild-type cells exposed to Cu-64 is significantly higher than gamma rays and almost equivalent to that irradiated with C ions with a linear energy transfer of 70 keV/μm.
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Mejía C, da Costa CAP, Iza P, da Silveira EF. Irradiation of Phenylalanine at 300 K by MeV Ions. ASTROBIOLOGY 2022; 22:439-451. [PMID: 35427147 DOI: 10.1089/ast.2021.0017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phenylalanine (Phe) is an amino acid that has been identified in carbonaceous meteorites; its formation mechanism in space is unknown, and its radioresistance has been the subject of investigation. This work aims at studying, in the laboratory, the Phe radiolysis by cosmic analogues. The Phe destruction rate, at 300 K, is measured for H, He, and N ion beam irradiation in the 0.5 to 2 kinetic MeV range. Fourier transform infrared (FTIR) spectroscopy was employed to monitor the molecular degradation as a function of fluence. The Phe apparent destruction cross-section, σapd, which includes radiolysis and sputtering processes, is determined to be proportional to the electronic stopping power, Se. The measured parameter D0 = 14.3 ± 2.2 eV/molec in the relationship, and σdap = Se/D0 is interpreted as the mean absorbed dose necessary to dissociate or eject a Phe molecule. The Phe half-life in the interstellar medium is predicted to be about 10 million years, H+ ions the main destructive cosmic ray constituent.
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Affiliation(s)
- Christian Mejía
- Facultad de Ciencias Químicas, Universidad de Cuenca, Cuenca, Ecuador
| | - Cíntia A P da Costa
- Physics Department, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Peter Iza
- Departamento de Física, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador
| | - Enio F da Silveira
- Physics Department, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
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6
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Watkins P, Hughes J, Gamage TV, Knoerzer K, Ferlazzo ML, Banati RB. Long term food stability for extended space missions: a review. LIFE SCIENCES IN SPACE RESEARCH 2022; 32:79-95. [PMID: 35065765 DOI: 10.1016/j.lssr.2021.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 12/12/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
At present, human spaceflight is confined to low Earth orbit but, in future, will again go to the Moon and, beyond, to Mars. The provision of food during these extended missions will need to meet the special nutritional and psychosocial needs of the crew. Terrestrially grown and processed food products, currently provided for consumption by astronauts/cosmonauts, have not yet been systematically optimised to maintain their nutritional integrity and reach the shelf-life necessary for extended space voyages. Notably, space food provisions for Mars exploration will be subject to extended exposure to galactic cosmic radiation and solar particle events, the impact of which is not fully understood. In this review, we provide a summary of the existing knowledge about current space food products, the impact of radiation and storage on food composition, the identification of radiolytic biomarkers and identify gaps in our knowledge that are specific in relation to the effect of the cosmic radiation on food in space.
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Affiliation(s)
- Peter Watkins
- CSIRO, Agriculture and Food, 671 Sneydes Road, Werribee, Vic 3030, Australia; CSIRO, Space Technology Future Science Platform, 41 Boggo Road, Dutton Park, Qld 4102, Australia.
| | - Joanne Hughes
- CSIRO, Agriculture and Food, 39 Kessels Road, Coopers Plains, Qld 4108, Australia; CSIRO, Space Technology Future Science Platform, 41 Boggo Road, Dutton Park, Qld 4102, Australia
| | - Thambaramala V Gamage
- CSIRO, Agriculture and Food, 671 Sneydes Road, Werribee, Vic 3030, Australia; CSIRO, Space Technology Future Science Platform, 41 Boggo Road, Dutton Park, Qld 4102, Australia
| | - Kai Knoerzer
- CSIRO, Agriculture and Food, 671 Sneydes Road, Werribee, Vic 3030, Australia; CSIRO, Space Technology Future Science Platform, 41 Boggo Road, Dutton Park, Qld 4102, Australia
| | - Mélanie L Ferlazzo
- ANSTO, Human Health (Space Health Program), New Illawarra Road, Lucas Heights, NSW 2234, Australia; Inserm, U1296 unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 28, rue Laennec, 69008 Lyon, France
| | - Richard B Banati
- ANSTO, Human Health (Space Health Program), New Illawarra Road, Lucas Heights, NSW 2234, Australia
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Methodological and Conceptual Progresses in Studies on the Latent Tracks in PADC. Polymers (Basel) 2021; 13:polym13162665. [PMID: 34451202 PMCID: PMC8398540 DOI: 10.3390/polym13162665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 11/24/2022] Open
Abstract
Modified structure along latent tracks and track formation process have been investigated in poly (allyl diglycol carbonate), PADC, which is well recognized as a sensitive etched track detector. This knowledge is essential to develop novel detectors with improved track registration property. The track structures of protons and heavy ions (He, C, Ne, Ar, Fe, Kr and Xe) have been examined by means of FT-IR spectrometry, covering the stopping power region between 1.2 to 12,000 eV/nm. Through a set of experiments on low-LET radiations—such as gamma ray-, multi-step damage process by electron hits was confirmed in the radiation-sensitive parts of the PADC repeat-unit. From this result, we unveiled for the first-time the layered structure in tracks, in relation with the number of secondary electrons. We also proved that the etch pit was formed when at least two repeat-units were destroyed along the track radial direction. To evaluate the number of secondary electrons around the tracks, a series of numerical simulations were performed with Geant4-DNA. Therefore, we are proposing new physical criterions to describe the detection thresholds. Furthermore, we propose a present issue of the definition of detection threshold for semi-relativistic C ions. Additionally, as a possible chemical criterion, formation density of hydroxyl group is suggested to express the response of PADC.
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8
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Quantitative estimation of track segment yields of water radiolysis species under heavy ions around Bragg peak energies using Geant4-DNA. Sci Rep 2021; 11:1524. [PMID: 33452450 PMCID: PMC7810756 DOI: 10.1038/s41598-021-81215-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/05/2021] [Indexed: 11/08/2022] Open
Abstract
We evaluate the track segment yield G' of typical water radiolysis products (eaq-, ·OH and H2O2) under heavy ions (He, C and Fe ions) using a Monte Carlo simulation code in the Geant4-DNA. Furthermore, we reproduce experimental results of ·OH of He and C ions around the Bragg peak energies (< 6 MeV/u). In the relatively high energy region (e.g., > 10 MeV/u), the simulation results using Geant4-DNA have agreed with experimental results. However, the G-values of water radiolysis species have not been properly evaluated around the Bragg peak energies, at which high ionizing density can be expected. Around the Bragg peak energy, dense continuous secondary products are generated, so that it is necessary to simulate the radical-radical reaction more accurately. To do so, we added the role of secondary products formed by irradiation. Consequently, our simulation results are in good agreement with experimental results and previous simulations not only in the high-energy region but also around the Bragg peak. Several future issues are also discussed regarding the roles of fragmentation and multi-ionization to realize more realistic simulations.
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9
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Kusumoto T, Ogawara R, Igawa K, Baba K, Konishi T, Furusawa Y, Kodaira S. Scaling parameter of the lethal effect of mammalian cells based on radiation-induced OH radicals: effectiveness of direct action in radiation therapy. JOURNAL OF RADIATION RESEARCH 2021; 62:86-93. [PMID: 33313873 PMCID: PMC7779345 DOI: 10.1093/jrr/rraa111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/06/2020] [Indexed: 06/12/2023]
Abstract
We have been studying the effectiveness of direct action, which induces clustered DNA damage leading to cell killing, relative to indirect action. Here a new criterion Direct Ation-Based Biological Effectiveness (DABBLE) is proposed to understand the contribution of direct action for cell killing induced by C ions. DABBLE is defined as the ratio of direct action to indirect action. To derive this ratio, we describe survival curves of mammalian cells as a function of the number of OH radicals produced 1 ps and 100 ns after irradiation, instead of the absorbed dose. By comparing values on the vertical axis of the survival curves at a certain number of OH radicals produced, we successfully discriminate the contribution of direct action induced by C ions from that of indirect action. DABBLE increases monotonically with increasing linear energy transfer (LET) up to 140 keV/μm and then drops, when the survival curves are described by the number of OH radicals 1 ps after irradiation. The trend of DABBLE is in agreement with that of relative biological effectiveness (RBE) of indirect action. In comparison, the value of DABBLE increases monotonically with LET, when the survival curves are described by the number of OH radicals 100 ns after irradiation. This finding implies that the effectiveness of C ion therapy for cancer depends on the contribution of direct action and we can follow the contribution of direct action over time in the chemical phase.
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Affiliation(s)
- Tamon Kusumoto
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Ryo Ogawara
- Advanced Research Center for Beam Science, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kazuyo Igawa
- Neutron Therapy Research Center, Okayama University, 2-5-1 Shikata, Kita-ku, 700-8558 Okayama, Japan
| | - Kentaro Baba
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Kita-12 Nishi-5, Kita-ku, 080-0808 Hokkaido, Japan
| | - Teruaki Konishi
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Yoshiya Furusawa
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Satoshi Kodaira
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
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Kusumoto T, Barillon R, Okada S, Yamauchi T, Kodaira S. Improved criterion of the mechanism for forming latent tracks in poly(allyl diglycol carbonate) based on the number of interactions induced by secondary electrons. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106445] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Kusumoto T, Kitamura H, Hojo S, Konishi T, Kodaira S. Significant changes in yields of 7-hydroxy-coumarin-3-carboxylic acid produced under FLASH radiotherapy conditions. RSC Adv 2020; 10:38709-38714. [PMID: 35517542 PMCID: PMC9057355 DOI: 10.1039/d0ra07999e] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 09/27/2020] [Indexed: 12/15/2022] Open
Abstract
FLASH radiotherapy appears to kill off tumor cells while sparing healthy tissues, by irradiation at ultra high dose rate (>40 Gy s−1). The present study aims to clarify the mechanism of the sparing effect by proton irradiation under the FLASH conditions from a viewpoint of radiation chemistry. To do so, we evaluate radiation chemical yields (G values) of 7-hydroxy-coumarin-3-carboxylic acid (7OH–C3CA), which is produced by water radiolysis using coumarin-3-carboxylic acid (C3CA) solution as a radical scavenger of hydroxyl radicals. We shoot 27.5 MeV protons in the dose rate ranging from 0.05 to 160 Gy s−1. The recombination process of hydroxyl radicals produced is followed by varying the concentration of C3CA from 0.2 to 20 mM, which corresponds to the scavenging time scale from 7.1 to 714 ns. The G value of 7OH–C3CA produced decreases with increasing dose rate on the same scavenging time scale. Additionally, the trend of the relative G value normalized at a scavenging time scale of 100 ns, where radical–radical reaction subsides, is consistent in the examined dose rate range. This finding implies that G values of 7OH–C3CA produced reduce with increasing dose rate due to the oxygen depletion. We experimentally present that the sparing effect for healthy tissues would be seen even with a proton beam under the FLASH conditions due to the depletion of oxygen. Yield of 7-hydroxy-coumarin-3-carboxylic acid (7OH–C3CA) significantly decreases at FLASH condition with the dose rate of >40 Gy s−1, compared to that at conventional condition of 0.05 Gy s−1, due to the oxygen depletion in the solution.![]()
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Affiliation(s)
- Tamon Kusumoto
- National Institutes for Quantum and Radiological Science and Technology 4-9-1 Anagawa, Inage-ku 263-8555 Chiba Japan
| | - Hisashi Kitamura
- National Institutes for Quantum and Radiological Science and Technology 4-9-1 Anagawa, Inage-ku 263-8555 Chiba Japan
| | - Satoru Hojo
- National Institutes for Quantum and Radiological Science and Technology 4-9-1 Anagawa, Inage-ku 263-8555 Chiba Japan
| | - Teruaki Konishi
- National Institutes for Quantum and Radiological Science and Technology 4-9-1 Anagawa, Inage-ku 263-8555 Chiba Japan
| | - Satoshi Kodaira
- National Institutes for Quantum and Radiological Science and Technology 4-9-1 Anagawa, Inage-ku 263-8555 Chiba Japan
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12
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Kusumoto T, Ogawara R. Radiation Chemical Yield of Hydroxyl Radicals for Accelerator-based Boron Neutron Capture Therapy: Dose Assessment of 10B(n,α) 7Li Reaction Using Coumarin-3-Carboxilic Solution. Radiat Res 2019; 191:460-465. [PMID: 30896280 DOI: 10.1667/rr15318.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Evaluation of the characteristics of accelerator-based thermal neutron fields is recognized as an important issue when discussing the effectiveness of boron neutron capture therapy (BNCT). In this study, we propose that the radiation chemical yield (G value) of hydroxyl radicals (Goh•) can be considered a universal parameter for the description of the accelerator-based thermal neutron field. The Goh• of the 10B(n,α)7Li reaction was quantitatively evaluated using an aqueous coumarin-3-carboxylic acid (3CCA) solution, and was discriminated from that of contaminations (i.e., γ rays and fast neutrons). The Goh• of the 10B(n,α)7Li reaction was 0.107 ± 0.004 OH•/100 eV, which is almost equivalent to that exposed to α particles with an energy of 6.0 MeV. Since the Goh• of γ rays from a 60Co source is 2.03 ± 0.05 OH•/100 eV, this lower value suggests that indirect action by the 10B(n,α)7Li reaction is not dominant in BNCT. However, our results indicate that one can assess the 60Co equivalent dose of the 10B(n,α)7Li reaction in water from the Goh• derived using aqueous 3CCA solution in the accelerator-based thermal neutron field.
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Affiliation(s)
- Tamon Kusumoto
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Ryo Ogawara
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
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