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Journal Articles

Accuracy check of Monte Carlo simulation in particle therapy using gel dosimeters

Furuta, Takuya

Igaku Butsuri, 37(3), p.177 - 180, 2017/00

Gel dosimeters are gelated aqueous solutions of radiosensitive substances and useful tools to visualize three-dimensional dose distribution of radiations. A study which uses gel dosimeters to quantify the dose distribution in biological samples is explained. In this study, the measured distribution was compared with the simulation result of PHITS to check the accuracy of Monte Carlo simulation in particle therapy situations. The comparison shows that the measured complex distal edge structure of the dose distribution reflecting the particle transport in inhomogeneous biological sample was reproduced by simulation with a precision of 2 mm difference. The result also shows that gel dosimeters are powerful tools to visualize three-dimensional dose distribution and have potential to be used for various purposes such as quality assurance of treatment beams as well as accuracy check of simulations.

Journal Articles

Effect of heavy ion irradiation on optical property of radiation-crosslinked hydroxypropyl cellulose gel containing methacrylate monomers

Hiroki, Akihiro; Yamashita, Shinichi*; Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

Nuclear Instruments and Methods in Physics Research B, 365(Part B), p.583 - 586, 2015/12

Effects of liner energy transfer (LET) and dose rate on the optical property of polymer gel dosimeters were investigated. The dosimeter prepared by using a radiation-crosslinked hydroxypropyl cellulose gel and methacrylate monomers such as 2-hydroxyethyl methacrylate and nonaethylene glycol dimethacrylate showed the color change from colorless to white with the He, C, Fe ions irradiation. Absorbance of the irradiated dosimeters increased with the dose up to 10 Gy. The absorbance of the dosimeters at the same total dose decreased with increasing dose rate in the range of 0.1 to 6.8 Gy/min. The absorbance decreased in order of He, C, Fe ions, which was in agreement with a change of LET. The increase in LET affected the decrease in the number of polymerization initiator such as OH radical and hydrated electron, resulting in the reduction of the absorbance of the dosimeters.

Journal Articles

Enhancement in dose sensitivity of polymer gel dosimeters composed of radiation-crosslinked gel matrix and less toxic monomers

Hiroki, Akihiro; Yamashita, Shinichi*; Taguchi, Mitsumasa

Journal of Physics; Conference Series, 573(1), p.012028_1 - 012028_4, 2015/01

BB2014-0610.pdf:0.75MB

 Times Cited Count:4 Percentile:12.73

Polymer gel dosimeters based on radiation-crosslinked hydroxypropyl cellulose gel were prepared, which comprised 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol dimethacrylate (9G) as less toxic monomers and tetrakis (hydroxymethyl) phosphoniumu chloride (THPC) as an antioxidant. The dosimeters exposed to $$^{60}$$Co $$gamma$$-rays became cloudy at only 1 Gy. The irradiated dosimeters were optically analyzed by using a UV-vis spectrophotometer to evaluate dose response. Absorbance of the dosimeters linearly increased in the dose range from 0 to 10 Gy. The dose sensitivity increased with increasing 9G concentration. The dosimeter with 2 wt% HEMA, 3 wt% 9G, and 0.16 wt% THPC exhibited about 0.04 Abs Gy$$^{-1}$$ of the dose sensitivity. The dose sensitivity of the dosimeters was also enhanced by increment in THPC, reached about 0.06 Abs Gy$$^{-1}$$ at 0.40 wt% THPC.

Oral presentation

LET dependence on the dose response of the polymer gel dosimeter based on radiation-crosslinked hydroxypropyl cellulose gel

Hiroki, Akihiro; Yamashita, Shinichi*; Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

no journal, , 

Polymer gel dosimeters consisting of 2-hydroxyethyl methacrylate, polyethylene glycol dimethacrylate, and tetrakis (hydroxymethyl) phosphoniumu chloride with radiation-crosslinked hydroxypropyl cellulose gel were prepared. The prepared dosimeters were irradiated with 150 MeV/u He ions, 290 MeV/u C ions, and 500 MeV/u Fe ions at HIMAC, in which a linear energy transfer (LET) of He, C, and Fe ions were 2.2, 13, and 182 eV/nm, respectively. Absorbance of the irradiated dosimeters increased with an increase in the dose up to 10 Gy. The absorbance at total doses of 5 Gy decreased with increasing dose rate in all of the heavy ions. The dosimeter irradiated with Fe ions exhibited the lowest absorbance in these samples. It was found that the absorbance decreased with increasing dose rate as well as LET of the heavy ions.

Oral presentation

Polymer gel dosimeters prepared by using a radiation crosslinked technique; Dose response to heavy ion irradiation on the basis of absorbance and image data

Hiroki, Akihiro; Yamashita, Shinichi*; Taguchi, Mitsumasa; Murakami, Takeshi*

no journal, , 

no abstracts in English

Oral presentation

Dose response of polymer gel dosimeter based on hydroxypropyl cellulose hydrogel; Toward the application on heavy ion therapy

Hiroki, Akihiro; Yamashita, Shinichi*; Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

no journal, , 

The polymer gel dosimeters consisting of 2-hydroxyethyl methacrylate, nonaethylene glycol dimethacrylate, and tetrakis (hydroxymethyl) phosphoniumu chloride with radiation-crosslinked hydroxypropyl cellulose gel were irradiated with 290 MeV/u C ions at HIMAC. Absorbance of the irradiated dosimeters at 660 nm increased with an increase in the dose up to 10 Gy. The dose response of the dosimeter irradiated with C ions was about 0.007 Abs. Gy$$^{-1}$$, which decreased in about one-tenth of the $$gamma$$-irradiated sample. RGB value of the image obtained by using a flat-bed image scanner also increased with increasing dose. Distribution of the dose estimated from RGB value of the scanned image was almost agreement with that of a general radiochromic film for the radiotherapy.

Oral presentation

For practical production of gel dosimeter for radiation therapy

Taguchi, Mitsumasa; Hiroki, Akihiro; Takaoka, Toshihito*; Koyama, Yudai*; Kuroiwa, Hiroki*; Oyake, Masaru*

no journal, , 

no abstracts in English

7 (Records 1-7 displayed on this page)
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