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Journal Articles

Radiation chemical reactions in water radiolysis with therapeutic heavy ion beams

Yamashita, Shinichi

Hoshasen Kagaku (Internet), (90), p.11 - 16, 2010/09

Water radiolysis with heavy-ion beams of energies up to 28 GeV provided from HIMAC (Heavy Ion Medical Accelerator in Chiba), NIRS (National Institute of Radiological Sciences) has been investigated from the viewpoint of correlation of products yields with track structure and its dynamics. For wide variety of heavy-ion beams in terms of LET, velocity, charge, etc., primary yields of major products in water radiolysis, $${rm e}_{{rm aq}}^-$$, $$^{bullet}$$OH and H$$_{2}$$O$$_{2}$$, have been measured by employing scavenging method to convert transient water radicals into stable and easily detectable species. Temporal behavior of approximate sum of water radicals has also been experimentally measured by a scavenging method with methyl viologen cation and formate anion. A Monte-Carlo simulation code of water radiolysis developed by a group of Universit$'e$ de Sherbrooke, Canada was complementally used in discussion of microscopic track structure and its dynamics. In addition, a fluorescent probe, 7-hydroxyl-coumarin-3-carboxylic acid, was utilized in sensitive $$^{bullet}$$OH detection with HPLC connected fluorometry.

Journal Articles

Water radiolysis with heavy ions of energies up to 28 GeV, 3; Measurement of ${it G}$(MV$$^{.+}$$) in deaerated methyl viologen solutions containing various concentrations of sodium formate and Monte Carlo simulation

Yamashita, Shinichi; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Miyazaki, Toyoaki*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

Radiation Research, 170(4), p.521 - 533, 2008/10

https://doi.org/10.1667/RR1203.1
 Times Cited Count：7 Percentile：27.16(Biology)

Formation yields of methyl viologen cation radicals ${it G}$(MV$$^{.+}$$) (100 eV)$$^{-1}$$ have been measured in deaerated aqueous solutions of methyl viologen, MV$$^{2+}$$, containing various concentrations of formate anion after irradiation with six different ion beams (from $$^{4}$$He$$^{2+}$$ to $$^{56}$$Fe$$^{26+}$$ with incident energies varying from 0.6 to 28 GeV) provided by HIMAC at NIRS in Japan. In parallel to the above measurements, Monte Carlo simulations of the radiolysis of the MV$$^{2+}$$-formate solutions have been performed to investigate complementarily mechanism from which distinctive irradiation effects of heavy ions are derived from the microscopic viewpoints experimentally non-feasible.

Journal Articles

Effect of water density on the absorption maximum of hydrated electrons in sub- and supercritical water up to 400 $$^{circ}$$C

Jay-Gerin, J.-P.*; Lin, M.; Katsumura, Yosuke; He, H.*; Muroya, Yusa*; Meesungnoen, J.*

Journal of Chemical Physics, 129(11), p.114511_1 - 114511_7, 2008/09

https://doi.org/10.1063/1.2978955
 Times Cited Count：22 Percentile：61.32(Chemistry, Physical)

In this work, we measure the density dependent absorption spectra of hydrated electron in D$$_{2}$$O at 380, 390, and 400$$^{circ}$$C, and then compare with the literature data for subcritical water. The results show that at a fixed pressure (25 MPa), ${it E$_{A-max}$}$ decreases monotonically with increasing temperature in passing through the liquid-supercritical water (SCW) phase transition at t$$_{c}$$. By contrast, at a fixed density (0.2 and 0.65g/cm$$^{3}$$), ${it E$_{A-max}$}$ exhibits a minimum near ${it t$_{c}$}$. These behaviors are explained in terms of local density and configurational fluctuations of water structure in SCW.

Oral presentation

Investigation on initial structure of heavy-ion track in water radiolysis; Simulation based on diffusion kinetic model and comparison of proposed track structures

Yamashita, Shinichi*; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

Simulation based on diffusion kinetic model has been carried out to investigate on "initial" track structure at 10$$^{-12}$$ s formed by heavy-ion irradiation and to compare with reported values such as primary yields in pure water and ${it G}$(Fe$$^{3+}$$) in the Fricke solution. Several dose distributions proposed in literatures were taken into the simulation. Spatial distributions of "initial" products at 10$$^{-12}$$ s calculated with Monte-Carlo simulation were compared with the dose distributions reported in the literature.

Oral presentation

Water radiolysis with heavy ions of energies up to 28 GeV; Investigation of track structure and intra-track reactions

Yamashita, Shinichi*; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Miyazaki, Toyoaki*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

Oral presentation

Radiolysis of water with heavy ions of energies up to 28 GeV at HIMAC

Katsumura, Yosuke; Yamashita, Shinichi; Lin, M.; Muroya, Yusa*; Meesungnoen, J.*; Jay-Gerin, J.-P.*; Murakami, Takeshi*

no journal, , 

Oral presentation

Water radiolysis with heavy ions of wide range of energies; Investigation of initial track structure with deterministic simulations

Yamashita, Shinichi; Katsumura, Yosuke; Maeyama, Takuya*; Lin, M.; Muroya, Yusa*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

Water radiolysis with heavy ions, from helium to iron ions, of very high energies up to 28 GeV (namely several hundred MeV per nucleon) has been studied in this work. Simulations based on diffusion kinetic model were performed to examine correlation between initial track structures at the beginning of the chemical stage, 10-12 s, and primary yields as well as to estimate the validity of classical track structure model for highly energetic heavy ions.

Oral presentation

Water radiolysis with heavy ions; Correlation between heavy-ion track structure and primary yields

Yamashita, Shinichi; Katsumura, Yosuke; Maeyama, Takuya*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

Primary yields in water radiolysis with relativistic heavy ions from Heavy Ion Medical Accelerator in Chiba (HIMAC) of National Institute of Radiological Sciences (NIRS) have been measured covering wide range of beam conditions. Experimental results were summarized and compared with results obtained not only in a deterministic simulation but also in a stochastic one. Heavy-ion track structure was discussed from microscopic viewpoints based on the experimental and simulation results.

Oral presentation

Effect of water density on the absorption maximum of hydrated electrons in sub- and supercritical water up to 400 $$^{circ}$$C

Lin, M.; Jay-Gerin, J.-P.*; Katsumura, Yosuke; Muroya, Yusa*; Meesungnoen, J.*; Yamashita, Shinichi

no journal, , 

In this work, we measure the density dependent absorption spectra of hydrated electron in D$$_{2}$$O at 380, 390, and 400 $$^{circ}$$C, and then compare with the literature data for subcritical water. The results show that at a fixed pressure (25 MPa), ${it E$_{A}$}$-$$_{max}$$ decreases monotonically with increasing temperature in passing through the liquid-supercritical water (SCW) phase transition at ${it t$_{c}$}$. By contrast, at a fixed density (0.2 and 0.65 g/cm$$^{3}$$), ${it E$_{A}$}$-$$_{max}$$ exhibits a minimum near ${it t$_{c}$}$. These behaviours are explained in terms of local density and configurational fluctuations of water structure in SCW.

Oral presentation

Investigation on heavy-ion track structure in water using diffusion kinetic model simulation

Yamashita, Shinichi; Katsumura, Yosuke; Maeyama, Takuya*; Lin, M.; Muroya, Yusa*; Murakami, Takeshi*; Jay-Gerin, J.-P.*; Meesungnoen, J.*

no journal, , 

Although water is a main component of human cells and its interaction with ionizing radiations are of crucial importance, understanding of water radiolysis with heavy ions of energies comparable to those used in actual cancer treatments is not sufficient. Recently, such highly energetic heavy ions are available at the Heavy Ion Medical Accelerator in Chiba (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. We have carried out measurements of primary yields of main water decomposition products, hydrated electron (e$$^{-}$$$$_{aq}$$), hydroxyl radical ($$^{.}$$OH) and hydrogen peroxide (H$$_{2}$$O$$_{2}$$) with heavy ions from $$^{4}$$He$$^{2+}$$ to $$^{56}$$Fe$$^{26+}$$ of energies up to 28 GeV (corresponding LET varies from 2 to 700 keV/$$mu$$m) provided from the HIMAC. Note that primary yields are defined as the yields at 100 ns after irradiation, which can be regarded as a time scale when diffusions and intra-track reactions of initial products are almost terminated. Then, such yields are important because they inherently involve information of initial track structure and dynamics of water decomposition products during track expansion. In the present study, not only such measurements but also discussions based on the measured data were conducted by simulations.

Oral presentation

Water radiolysis with high-energy ion beams

Yamashita, Shinichi; Katsumura, Yosuke; Maeyama, Takuya*; Lin, M.; Muroya, Yusa*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

It is phenomenologically well known that heavy-ion beams, which are known to be typical high-LET radiations, give distinctive irradiation effects compared to more popular low-LET radiations such as electron beam and $$gamma$$-rays. Here, LET is abbreviation of linear energy transfer, defined as energy deposition from radiation to surrounding matter per unit length of its trajectory. Most of earlier studies focus lighter ions ($$^{1}$$H, etc.) of lower energies ($$<$$ 10 MeV/nucleon). Moreover, knowledge under neutral pH, which is close to human body, has not been accumulated well. In this study, it is purposed to investigate chemical change occurring in neutral aqueous solutions after irradiation of high-energy (10-500 MeV/nucleon) heavy ions ($$^{12}$$C, $$^{56}$$Fe, etc.). Especially, structure of heavy-ion track and radiation-chemical yields are discussed.

Oral presentation

Ion beam radiation chemistry relevant to radiation therapy

Katsumura, Yosuke; Yamashita, Shinichi; Lin, M.; Maeyama, Takuya*; Muroya, Yusa*; Baldacchino, G.*; Jay-Gerin, J.-P.*; Meesungnoen, J.*; Murakami, Takeshi*

no journal, , 

Oral presentation

Water radiolysis with heavy ions

Yamashita, Shinichi; Katsumura, Yosuke; Maeyama, Takuya*; Lin, M.; Muroya, Yusa*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

Water radiolysis with high-energy heavy ions has been investigated through measurement of product yield and simulation of intra-track reactions. Ions from helium to xenon of energies up to 500 MeV per nucleon were taken for irradiation at the biological irradiation port of HIMAC installed at NIRS, Japan. Taking long range of the ions, typically longer than 10 cm, as an advantage, track-segment yields of main water decomposition products, e$$^{-}$$$$_{aq}$$, $$bullet$$OH and H$$_{2}$$O$$_{2}$$, have been determined. Utilizing energy absorber made of PMMA, ion energies were decreased down to about 10 MeV per nucleon to vary beam properties in sample solutions, and then, product yields for wide ranges of ion types and energies were accumulated. Influences of scavenger concentration have also been discussed and yield of approximate sum of $$bullet$$OH, H$$bullet$$ and e$$^{-}$$$$_{aq}$$ was measured. In parallel to these measurements, Monte-Carlo simulation of intra-track reactions has been conducted not only to reproduce the experimental results but also to discuss further track structure and its dynamics from microscopic viewpoint.

Oral presentation

Ion beam radiation chemistry relevant to radiation therapy

Katsumura, Yosuke

no journal, , 

Water radiolysis has been investigated with ion beams such as He$$^{2+}$$, C$$^{6+}$$, Ne$$^{10+}$$, Si$$^{14+}$$, Ar$$^{14+}$$, Fe$$^{26+}$$, Kr$$^{36+}$$ and Xe$$^{54+}$$ having energies of several hundreds MeV per nucleon provided at HIMAC facility of the National Institute of Radiological Sciences. The ${it G}$ values of e$$^{-}$$$$_{aq}$$, $$^{.}$$OH and H$$_{2}$$O$$_{2}$$ as a function of LET at 100 ns after the energy deposition have been determined. The radical yields decrease but the molecular yield increases with increasing LET due to the track reactions. In addition, other trials to investigate intra-track dynamics with high-concentration scavenger and to develop and apply a sensitive method to determine $$^{.}$$OH yield, which is important in understanding of indirect action of ionizing radiations.

Oral presentation

Water radiolysis with therapeutic ion beam; Contribution of fragmentations to $$^{.}$$ OH yields estimated by PHITS

Funtowiez, D.*; Maeyama, Takuya*; Yamashita, Shinichi; Katsumura, Yosuke; Meesungnoen, J.*; Jay-Gerin, J.-P.*; Murakami, Takeshi*

no journal, , 

no abstracts in English

Oral presentation

Water radiolysis with heavy ions of energies up to 28 GeV

Yamashita, Shinichi; Katsumura, Yosuke; Maeyama, Takuya*; Baldacchino, G.*; Murakami, Takeshi*; Meesungnoen, J.*; Jay-Gerin, J.-P.*

no journal, , 

Water radiolysis with heavy ions has been investigated from the viewpoint of correlation between track structure and yields of water decomposition products. Primary yields of main products were determined for wide variety of heavy ion beams of energies up to 28 GeV provided at HIMAC (Heavy Ion Medical Accelerator in Chiba). A fluorescent probe, 7-hydroxyl-coumarin-3-carboxylic acid, was utilized in sensitive detection and quantification of hydroxyl radical. This method was extended to investigation of water radiolysis near the Bragg peak with considering fragmentation reactions. Gaseous products detection has also been started.

Oral presentation

Water radiolysis with high-energy heavy ions; Conversion of transient water radicals into stable product inside heavy-ion tracks

Yamashita, Shinichi; Katsumura, Yosuke; Meesungnoen, J.*; Jay-Gerin, J.-P.*; Lin, M.; Muroya, Yusa*; Murakami, Takeshi*

no journal, , 

Water radiolysis with high-energy heavy ions has been investigated through combination of yield measurement with scavenging method and track-structure simulation based on Monte-Carlo method. Deaerated aqueous solutions of 0.25 mM methyl viologen (MV) containing various concentration of sodium formate were irradiated with He, C, Ne, Si, Ar and Fe ions of 135-500 MeV per nucleon provided from HIMAC at NIRS, Japan. By changing formate concentration, yield of MV$$^{+.}$$ was measured for the abovementioned heavy-ion beams. Then, the yield of MV$$^{+.}$$ increased with decreasing LET and with increasing formate concentration. This fact shows that consumption of water radicals in intra-track reactions with time occurs and becomes more and more significant with increasing LET. In order to discuss more quantitatively, Monte-Carlo simulation code for water radiolysis with heavy ions named IONLYS-IRT, which has been developed by a group of University of Sherbrooke, was employed to reproduce our experimental results.

Oral presentation

Radiation chemical reactions in water radiolysis with therapeutic heavy ion beams

Yamashita, Shinichi

no journal, , 

Water radiolysis with heavy-ion beams of energies up to 28 GeV provided from HIMAC, NIRS has been investigated from the viewpoint of correlation of products yields with track structure and its dynamics. For wide variety of heavy-ion beams in terms of LET, velocity, charge, etc., primary yields of major products in water radiolysis, e$$^{-}$$$$_{aq}$$, $$^{bullet}$$OH and H$$_{2}$$O$$_{2}$$, have been measured by employing scavenging method to convert transient water radicals into stable and easily detectable species. Temporal behavior of approximate sum of water radicals has also been experimentally estimated. A Monte-Carlo simulation code of water radiolysis developed by a group of Universit$'e$ de Sherbrooke, Canada was complementally used in discussion of microscopic track structure and its dynamics. In addition, a fluorescent probe was utilized in sensitive $$^{bullet}$$OH detection with HPLC-connected fluorometry.

18 (Records 1-18 displayed on this page)
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