JP2002214354A - Resin composition for radiation dosimeter and its hardened form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition and its hardened form useful in accurately measuring a spatial distribution of dosages, that is, the quantity of radiation and its irradiation position, during treatments using radiotherapy apparatus. SOLUTION: The resin composition for a radiation dosimeter contains (A) a gellable compound; (B) a polymer having one or more ethylenic unsaturated double bonds in one molecule; and (C) a solvent. A hardened form of the resin composition is also disclosed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation containing a compound (A) capable of forming a gel, a polymer (B) having one or more ethylenically unsaturated double bonds in one molecule, and a solvent (C). The present invention relates to a resin composition for a dosimeter and a cured product thereof.
More specifically, the present invention relates to a resin composition useful for accurately measuring a spatial dose distribution when treating with a radiotherapy device, that is, an irradiation dose and an irradiation position thereof, and a cured product thereof.

[0002]

2. Description of the Related Art In recent years, as the number of cancer patients has increased, the frequency of radiotherapy has also increased. Radiation therapy is often used for those with high radiosensitivity such as malignant lymphoma and leukemia, and in cases where resection is difficult such as brain tumors and facial skin tumors. Taking the case of metastatic brain tumor as an example, radiation therapy can be divided into whole brain irradiation that irradiates the entire brain and partial irradiation that irradiates only the tumor part. The former is usually irradiated so as to cover the whole brain from two directions, left and right, and the latter is irradiated in a combination from the front, rear, left and right optimal directions for the purpose of concentrating the dose on the tumor as much as possible. The irradiation dose is 2 to 5 Gy once, 5 times a week, for a total of 30 to 50 Gy for 2 to 5 weeks.

Recently, for small tumors, treatment using a radiosurgery such as a gamma knife using a cobalt 60 source or a linac surgery using X-rays may be performed. In these treatments, a small tumor is irradiated with finely narrowed radiation from multiple directions to minimize damage to normal tissues around the tumor, and to irradiate a light dose intensively only on the tumor part.

Prior to these radiation treatments, CT (com
printed Tomography and MRI (magn
The location, number, size, etc., of the tumor are examined by ethic resonance imaging, and a three-dimensional treatment plan is created based on the patient data, in which the irradiation method and dose are determined. Next, radiation treatment is performed in accordance with the three-dimensional treatment plan, and positioning is performed to accurately irradiate the affected part with radiation. Conventionally, this positioning has been performed by using a lead wire or the like.
Although performed by radiography, there are problems such as low accuracy and long time for positioning.

[0005] Recently, quality control of radiotherapy has become a problem in Japan, and it has been required to make an accurate radiotherapy plan and to accurately determine the spatial dose distribution of irradiation. I have. In other words, an accurate three-dimensional radiation dosimeter has been required instead of positioning by radiography using a lead wire or the like.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventor has proposed a compound (A) capable of forming a gel, and having at least one ethylenically unsaturated double bond in one molecule. The present inventors have found that the above object can be achieved by using a resin composition for a radiation dosimeter containing the polymer (B) and the solvent (C), and have completed the present invention. That is, according to the present invention, (1) a compound (A) capable of forming a gel, a polymer (B) having one or more ethylenically unsaturated double bonds in one molecule (hereinafter referred to as a polymerizable polymer), and a solvent ( (2) The resin composition for a radiation dosimeter according to the above (1), wherein the solvent (C) is a solvent containing water. , (3) polymerizable polymer (B)
Is a polymer having one or more epoxy groups in one molecule (B
-1) and a compound (B-2) having one ethylenically unsaturated double bond carboxyl group per molecule in the molecule (1) or (2). Resin composition for dosimeter, (4) polymerizable polymer (B)
Is a water-soluble resin composition for a radiation dosimeter according to any one of the above (1) to (3), and (5) any one of the above (1) to (4). Phantom consisting of the resin composition for a radiation dosimeter according to the paragraph,
(6) The radiation dosimeter resin composition and the cured product of the phantom according to any one of the above (1) to (5),
(7) Compound (A) capable of forming a gel, polymer (B-1) having one or more epoxy groups in one molecule, and one ethylenically unsaturated double bond carboxyl group in one molecule The present invention relates to a resin composition comprising, as constituent components, a polymerizable polymer (B) obtained by a reaction of a compound (B-2) and a solvent (C) containing water.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition of the present invention comprises a compound (A) capable of forming a specific gel, a polymerizable polymer (B) and a solvent (C) for a radiation dosimeter. It is.

The gel-forming compound (A) used in the present invention includes natural polymers such as gums, polypeptides, polysaccharides, agarose, gelatin, karaya gum, carrageenan and starch; poly (meth) acrylic acid; (Meth) acrylic resin, polyvinyl alcohol, polysaponified vinyl acetate, polyester resin, polyether resin, polyurethane resin, polycarbonate resin,
Synthetic polymers such as polyacetal resin, carboxymethylcellulose, hydroxypropylcellulose, etc., having a molecular weight of 1,000 to 1,000,000
Is preferred. As a method of forming these gels, there are a covalent bond, a Coulomb force bond, a hydrogen bond, a coordination bond, and a physical entanglement, and any of them may be used. In order to keep the irradiation position unchanged after irradiating the phantom with radiation, a compound capable of forming a gel at room temperature is preferable. For example, if gelatin is explained as an example, JIS K6
The jelly strength specified in 503-1996 is 10
g or more is preferable, and 100 g or more is particularly preferable.

The polymerizable polymer (B) used in the present invention
Is not particularly limited as long as it has an ethylenic double bond that can be cross-linked by the action of radiation, but a polymer (B-1) having one or more epoxy groups in one molecule (hereinafter referred to as an epoxy-containing polymer) ) And a compound (B-2) having a hydroxy group obtained by the reaction of a compound (B-2) (hereinafter referred to as a polymerizable carboxylic acid) having one ethylenically unsaturated double bond and one carboxyl group in one molecule.
Alternatively, it may be a polymerizable polymer having a hydroxyl group or a carboxyl group and an ethylenically unsaturated double bond, such as a polymerizable polymer having a carboxyl group (B) obtained by reacting a polycarboxylic acid anhydride with the polymerizable anhydride. preferable. Further, the polymerizable polymer (B) used in the present invention is preferably water-soluble. The water-soluble polymerizable polymer (B) is usually a water-soluble epoxy-containing polymer (B).
The polymer obtained by using -1) can be obtained by converting it into a water-soluble salt, if necessary.

As the epoxy-containing polymer (B-1),
There is no particular limitation as long as it is a polymer containing an epoxy group. Usually, a copolymer of a polymerizable monomer having an epoxy group and a polymerizable monomer having no epoxy group (hereinafter referred to as a copolymerizable epoxy resin) is used. Preferably, more preferably acrylic (at least one of the polymerizable monomers used is (meth)
(In the case of a monomer containing an acrylic group) is preferred. As the polymerizable monomer having an epoxy group (epoxy-containing polymerizable monomer) used in the production of the epoxy-containing polymer (B-1), a polymerizable monomer having an epoxy group and a
There is no particular limitation as long as it is a monomer having a heavy bond, but usually a monomer having one epoxy group and one polymerizable double bond, and having about 5 to 12 carbon atoms contained in the molecule. Are preferred, for example, glycidyl (meth) acrylate,
(Meth) acryloylmethylcyclohexene oxide, vinylcyclohexene oxide and the like,
Acrylic monomers are preferred. The other polymerizable monomer having no epoxy group used in the production of the epoxy-containing polymer is not particularly limited, and a liquid or solid polymerizable monomer at room temperature is generally used, Compounds having one ethylenically unsaturated double bond which are liquid at room temperature are preferred. Examples of these compounds include, for example,
(Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) A) acrylate or glycerin mono (meth) acrylate and the following general formula (1)

CH ₂ ＣＲCR ₁ —CO—O— (C ₂ -C 4 alkylene-O) n—R ₂ (1)

[0012] (wherein _{R 1} is hydrogen or a methyl group, _{R 2}
Is hydrogen or a C1 to C6 alkyl group, and n is 2 to 2
(An integer of 3) (meth) acrylic acid esters such as polyethylene glycol ester of (meth) acrylic acid, and styrene-based monomers such as styrene and α-methylstyrene. Among these monomers, an acrylic monomer such as (meth) acrylic acid or an ester thereof is preferable, and the ester has 1 to 10 carbon atoms.
Ester with a mono- or polyalcohol (which may have a substituent such as an alkoxy group having 1 to 6 carbon atoms or a phenoxy group, and in the case of polyalcohol, the number of hydroxy groups is preferably about 2 to 3) Alternatively, a polyethylene glycol ester represented by the formula (1) is preferable. Examples of the compound of the formula (1) include polyethylene glycol mono (meth) acrylate such as diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, and tetraethylene glycol mono (meth) acrylate, and methoxydiethylene glycol mono (meth) acrylate. And methoxytriethylene glycol mono (meth) acrylate and methoxytetraethylene glycol mono (meth) acrylate. As the alkoxy group used here, for example, a lower alkoxy group having about 1 to 4 carbon atoms is preferable. Representative examples of the epoxy-containing polymer (B-1) used in the present invention include a copolymer type epoxy resin, and specifically, for example, a product number C manufactured by NOF Corporation
P-15, CP-30, CP-50, CP-20SA,
CP-510SA, CP-50S, CP-50M, CP
Copolymer type epoxy resins such as -20MA, and copolymers of glycidyl (meth) acrylate and polyethylene glycol ester of (meth) acrylic acid represented by the general formula (1) are exemplified.

The epoxy-containing polymer (B-1), for example, the above-mentioned copolymerizable epoxy resin has a molecular weight of about 1,000 to 20.
000, preferably from about 2,000 to 100,
000, more preferably from about 3,000 to 50,000
The epoxy equivalent is usually 50 or more, preferably 100 or more, and usually 1000 or less,
It is preferably about 700 or less. When the epoxy-containing polymer is produced by copolymerizing an epoxy-containing polymerizable monomer such as glycidyl (meth) acrylate with another monomer having no epoxy group, the amount of the epoxy-containing polymerizable monomer used Is usually 10 to 7 based on the total amount of the monomers used.
It is about 0% by mass, preferably about 20 to 50% by mass. The amount of the monomer containing no epoxy group is 90 to 30% by mass, preferably 80 to 50% by mass.

When the epoxy-containing polymer (B-1) is an acrylic polymer soluble in water, glycerin mono (meth) acrylate and / or a compound of the formula (1) may be used as a polymerizable monomer having no epoxy group. It is preferable to use 30% by weight or more, preferably 5% by weight, based on the total amount of the monomers used for producing the epoxy-containing polymer (B-1).
It is desirable that the content is 0% by weight or more and 90% by weight or less, preferably 80% by weight or less.

When the epoxy-containing polymer (B-1) is produced, it can be produced by a known polymerization method, for example, solution polymerization or emulsion polymerization. If the case of using solution polymerization is described, a mixture of an epoxy-containing polymerizable monomer and a polymerizable monomer having no epoxy group is preferably added under a nitrogen stream by adding a polymerization initiator in an applicable solvent. Polymerization is carried out by a method of heating and stirring at 50 to 100 ° C. Examples of the solvent include water, ethanol, propanol, isopropanol, butanol,
Alcohols such as isobutanol, 2-butanol, hexanol and ethylene glycol, ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, cellosolves such as cellosolve and butyl cellosolve, carbitol and butyl carbitol Carbitols, propylene glycol alkyl ethers such as propylene glycol methyl ether,
Polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether, etc .; acetates such as ethyl acetate, butyl acetate, cellosolve acetate and propylene glycol monomethyl acetate; lactate esters such as ethyl lactate and butyl lactate; dialkyl glycol ethers Is mentioned. These organic solvents can be used alone or in combination.

As the polymerization initiator, for example, a peroxide such as benzoyl peroxide and an azo compound such as azobisisobutyronitrile can be used.

The polymerizable carboxylic acid (B-2) used in the production of the polymerizable polymer (B) is particularly a compound having one ethylenically unsaturated double bond and one carboxyl group in one molecule. Although there is no limitation, typical examples include a half ester obtained by reacting (meth) acrylic acid or a hydroxyl group-containing (meth) acrylate with an acid anhydride of a polycarboxylic acid compound. Examples of the hydroxyl group-containing (meth) acrylate used as a raw material of the half ester include, for example, a hydroxy-substituted (C1-C6) alkyl (meth) acrylate which may have a substituent which does not adversely affect a reaction such as a hydroxy group. For example, 2-hydroxyethyl (meth) acrylate, 2
-Hydroxypropyl (meth) acrylate, 1,4-
Butanediol mono (meth) acrylate and the like. Examples of the acid anhydride of the polycarboxylic acid compound used as a raw material of the half ester include polycarboxylic acid anhydrides of aliphatic hydrocarbons having 2 to 4 carbon atoms having 2 to 4 carboxyl groups or 2 to 4 carboxyl groups. Examples include polycarboxylic anhydrides of aromatic hydrocarbons having a group having 6 to 10 carbon atoms, such as succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Is done.

When the polymerizable polymer (B) is obtained from the epoxy-containing polymer (B-1) and the polymerizable carboxylic acid (B-2), the carboxyl group of the polymerizable carboxylic acid (B-2) is converted to an epoxy-containing polymer. What is necessary is just to add to the epoxy group of a union (B-1), and just to make them react according to a usual method in presence of a catalyst etc. as needed. It is preferable to use 0.5 to 1.1 equivalents of the polymerizable carboxylic acid (B-2) with respect to 1 equivalent of the epoxy group of the epoxy-containing polymer (B-1). Further, a reaction solvent may be used if necessary, for example, ethanol, propanol,
Isopropanol, butanol, isobutanol, 2-
Alcohols such as butanol, hexanol and ethylene glycol, ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, cellosolves such as cellosolve and butyl cellosolve,
Propylene glycol alkyl ethers such as propylene glycol methyl ether, propylene glycol alkyl ethers such as dipropylene glycol methyl ether, ethyl acetate, butyl acetate, acetate esters such as cellosolve acetate, propylene glycol monomethyl acetate, ethyl lactate, lactic acid Lactic acid esters such as butyl, dialkyl glycol ethers, and the like. These organic solvents can be used alone or as a mixture.

In order to promote the reaction, a basic compound such as triphenylphosphine, triphenylstibine, triethylamine, triethanolamine, tetramethylammonium chloride, benzyltriethylammonium chloride or the like is added to the reaction solution in an amount of 0.1 to 10%. 1
% Is preferably added. During the reaction, it is preferable to add a polymerization inhibitor (for example, methoxyphenol, methylhydroquinone, hydroquinone, phenothiazine, etc.) in the reaction solution in an amount of 0.05 to 0.5% in order to prevent polymerization.
The reaction temperature is preferably 90 to 150 ° C, and the reaction time is preferably 5 to 40 hours.

When the polymerizable polymer (B) thus obtained has a hydroxyl group, the acid anhydride of the above-mentioned polycarboxylic acid compound may be added, if necessary, to 1 equivalent of the hydroxyl group of the polymerizable polymer (B). (E.g., succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc.) are preferably reacted at a rate of 0.2 to 1.0 equivalent of an anhydride group to form a carboxyl group. Having a polymerizable polymer (B). The reaction temperature is preferably 90 to 150 ° C, and the reaction time is preferably 3 to 30 hours.

The carboxyl group of the polymerizable polymer (B) having a carboxyl group thus obtained can be neutralized with a basic compound. Examples of the basic compound include triethylamine, N, N-dimethylbutylamine, tributylamine, triallylamine, N, N
-Dimethylallylamine, N-methyldiallylamine,
N, N-dimethylethanolamine, N, N-diethylmethanolamine, N, N-dibutylethanolamine, N, N-dimethylpropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine,
Triethanolamine, N-methylmorpholine, N-
Examples include tertiary amines such as ethyl morpholine, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. These basic compounds can be used alone or in combination of two or more. In the neutralization, it is preferable to add an aqueous solution of the basic compound dropwise while stirring the solution of the polymerizable polymer (B) having a carboxyl group. The polymerizable polymer (B) used in the present invention is preferably water-soluble. The molecular weight of the polymerizable polymer (B) used in the present invention is roughly determined by the molecular weight of the epoxy-containing polymer (B-1) used as a raw material, but is usually about 1,200 to 240,000.
Preferably it is about 2,500 to 120,000, more preferably about 3,500 to 60,000.

Solvent (C) which is a component of the composition of the present invention
As, water, an organic solvent miscible with water, or an organic solvent immiscible with water, and the like, for example, water, ethanol,
Alcohols such as propanol, isopropanol, butanol, isobutanol, 2-butanol, hexanol, and ethylene glycol, preferably polyalcohols having 1 to 6 carbon atoms or having 2 to 3 hydroxy groups,
Ketones such as methyl ethyl ketone and cyclohexanone,
Ketones having 1 to 6 carbon atoms, aromatic hydrocarbons such as toluene and xylene, mono or polyalkylene glycol mono or dialkyl ethers, preferably mono or poly mono or dialkylene glycol having 1 to 3 carbon atoms Alkyl ethers having 1 to 4 carbon atoms, ethyl acetate,
Examples thereof include acetates such as butyl acetate, cellosolve acetate, and propylene glycol monomethyl acetate, and lactate esters such as ethyl lactate and butyl lactate.
As the above mono- or polyalkylene glycol mono- or dialkyl ethers, cellosolves such as cellosolve and butyl cellosolve, preferably alkylcellosolve having 1 to 4 carbon atoms, propylene glycol alkyl ethers such as propylene glycol methyl ether, dipropylene glycol methyl ether And the like. These organic solvents can be used alone or in combination. The solvent may be a single solvent of water in some cases, but is preferably an organic solvent containing water. Water content is usually 10% -99
%, Preferably about 20 to 95%.

The general range of use of each component is that the compound (A) capable of forming a gel is 0.01 to 50% by weight, the polymerizable polymer (B) is 0.01 to 50% by weight, and the solvent (C) is Is 0.01 to 99.98% by weight, preferably 1 to 30% by weight of the compound (A) capable of forming a gel, 1 to 30% by weight of the polymerizable polymer (B), and 1 to 30% by weight of the solvent (C). 40-9
8% by weight, more preferably 2-20% by weight of the compound (A) capable of forming a gel, and 3% by weight of the polymerizable polymer (B).
-20% by weight and the solvent (C) is 60-95% by weight.

In the present invention, a photopolymerization initiator (D) may be used. Examples of the photopolymerization initiator (D) include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone,
2,2-dimethoxy-2-phenylacetophenone,
2,2-diethoxy-2-phenylacetophenone,
1,1-dichloroacetophenone, 2-hydroxy-2
Acetophenones such as -methyl-1-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one Anthraquinones such as 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-chloroanthraquinone and 2-amylanthraquinone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone and 4,4-bismethylaminobenzophenone; and 2,4,6-trimethylbenzoyldiphenylphos Fin oxide are listed.

These can be used alone or as a mixture of two or more. Further, tertiary amines such as triethanolamine and methyldiethanolamine, ethyl N, N-dimethylaminobenzoate, N, N-dimethylaminobenzoate It can be used in combination with an accelerator such as a benzoic acid derivative such as acid isoamyl ester.

The photopolymerization initiator (D) is used in an amount of 0.5 to 20 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of the total weight of the components (A), (B) and (C). A ratio of 15 parts by weight is preferable.

In the present invention, if necessary, various additives such as fillers such as talc, barium sulfate, calcium carbonate, magnesium carbonate, barium titanate, aluminum hydroxide, aluminum oxide, silica, clay, aerosil Thixotropic agents such as phthalocyanine blue, phthalocyanine green, and titanium oxide; silicone, fluorine-based leveling agents and defoamers; and polymerization inhibitors such as hydroquinone and hydroquinone monomethyl ether to enhance various performances of the composition. It can be added for the purpose.

[0028] The resin composition of the present invention can be obtained by mixing, dissolving or dispersing the above components. The temperature for mixing, dissolving or dispersing is preferably 20 to 100 ° C., and the time is 3 minutes.
0 minutes to 10 hours are preferred.

The resin composition of the present invention can be filled in a container to form a phantom. There is no particular limitation on the container as long as it does not respond to MRI, transmits radiation, has solvent resistance, airtightness, etc., and is made of glass, quartz, acrylic resin, polyvinyl chloride, polyester, polycarbonate, polytetrafluoroethylene. And polyacrylonitrile are preferred. After filling the container, it may be replaced with nitrogen gas or the like.

In recent radiotherapy, a new irradiation technique IMRT for preserving organs and stereotactic radiotherapy of the head region are becoming widespread and established. For these high-precision radiation treatments, it is essential to match the radiation treatment plan and post-irradiation. As a method of demonstrating a radiation treatment plan using the resin composition of the present invention,
First, a region of interest (irradiation site) for treatment is set based on an X-ray simple radiograph or CT image of the affected part. The total dose (radiation quality, irradiation time, number of irradiation gates) is determined by the affected area and the irradiation site.
When the resin composition is irradiated to the human body under the same conditions before the irradiation, the irradiated part is cured. This resin composition was used for one irradiation (3G
y) and for several irradiations (IMRT) (25-35 Gy). Next, the cured product is measured by MRI. This is because, when the resin composition is cured by irradiation with radiation, the molecular motion of that part is restricted, and the relaxation time (T1 and T2)
Is different from the unirradiated part. By comparing the MRI data with the data of the treatment plan and the region of interest (irradiation site), it is possible to confirm whether or not the affected part is accurately irradiated before the irradiation.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to the following Examples. In the following, “parts” means “parts by weight” unless otherwise specified.

Synthesis Example 1 (Synthesis Example of Polymer (B) Having One or More Ethylenically Unsaturated Double Bonds in One Molecule) A copolymerization type epoxy resin ( Nippon Yushi Co., Ltd., Blemmer CP-50M, epoxy equivalent 3
10, average molecular weight 6000) 310 parts, acrylic acid 72
Parts, 0.3 parts of methylhydroquinone, 194 parts of diethylene glycol monoether acetate, and 1.8 parts of triphenylphosphine, and reacted at 95 ° C. for 32 hours. Then, 70 parts of succinic anhydride was charged and reacted at 95 ° C. for 15 hours. Then, 380 g of a 10% aqueous sodium carbonate solution and 1500 g of water were added to obtain a polymer having a weight average molecular weight of 20,000 and a solid content of 18%.

Synthesis Example 2 (Synthesis example of polymer (B) having one or more ethylenically unsaturated double bonds in one molecule) 75 parts of tetraethylene glycol monomethacrylate, 25 parts of glycidyl methacrylate, 100 parts of diethylene glycol monoethyl ether acetate And 2 parts of azobisisobutyronitrile, and the mixture was heated under a nitrogen stream and polymerized at 75 ° C. for 5 hours to obtain a 50% polymer solution. Then, this 50%
300 parts of the polymer solution, 19 parts of acrylic acid, 0.16 part of methylhydroquinone, and 0.9 part of triphenylphosphine were mixed and dissolved, and reacted at 95 ° C. for 32 hours to obtain a reaction product solution. The average molecular weight of the reaction was about 80,000.

Examples 1 to 6 Each material was mixed at a mixing ratio shown in Table 1 at 80.degree.
One glass bottle was filled and replaced with nitrogen gas to prepare a sample for measurement. Next, MRI measurement was performed on a sample irradiated with 5 Gy of γ-rays and on a sample that had not been irradiated with γ-rays to obtain signal intensities in T2-weighted images. Evaluation criteria are: signal intensity ratio = signal intensity before irradiation / signal intensity after irradiation: ○: signal intensity ratio is 2 or more ×: signal intensity ratio is 2 or less In addition, the resin composition is filled in a 2 l round bottom flask. And the atmosphere was replaced with nitrogen to prepare a sample for measurement. Then, a brain stereotaxic mask was applied thereto, γ-rays were irradiated at 5 Gy, MRI measurement was performed, and the irradiation position was specified. Next, after leaving at room temperature for one month, MRI measurement was performed again. The evaluation criteria of the preservability were as follows: ：: Irradiation position does not change from the initial state even after standing X: Irradiation position changes from the initial state after standing

[0035]

[Table 1]

Note) *) CLV: Gelatin (manufactured by Nitta Gelatin Co., Ltd.)

As is evident from the results shown in Table 1, the resin composition of the present invention gives a good MRI image upon irradiation with radiation and has excellent storage stability.

[0038]

According to the present invention, radiation containing a gel-forming compound (A), a polymer (B) having one or more ethylenically unsaturated double bonds in one molecule, and a solvent (C). When using a resin composition for a dosimeter and a cured product thereof, a spatial dose distribution when treating with a radiotherapy device,
That is, it is useful for accurately measuring the irradiation dose and the irradiation position.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01T 1/04 G01T 1/04 1/161 1/161 Z (72) Inventor Hirotoshi Sasaki Tsukishima, Chuo-ku, Tokyo 2-15-13 CBC Corporation (72) The inventor Junsuke Tsukamoto 2-15-13 Tsukishima Tsukishima, Chuo-ku, Tokyo F-term (reference) 2G088 BB07 BB19 EE01 FF02 FF04 FF17 FF19 JJ27 KK33 4J002 AB01W AB03W AB05W AD03W AE05W AF03W BE02W BF02W BG00W BG01W CB00W CD20X CF00W CG00W CH00W CK02W DF026 FD206 HA04 HA08 4J027 AA02 AE01 CA01 CA08 CA08

Claims (7)

[Claims] A gel-forming compound (A), a polymer (B) having one or more ethylenically unsaturated double bonds in one molecule (hereinafter referred to as a polymerizable polymer) and a solvent (C). A resin composition for a radiation dosimeter, comprising: 2. The resin composition for a radiation dosimeter according to claim 1, wherein the solvent (C) is a solvent containing water. 3. A polymerizable polymer (B) comprising a polymer (B-1) having one or more epoxy groups in one molecule and one ethylenically unsaturated double bond and one carboxyl group in one molecule. The resin composition for a radiation dosimeter according to claim 1, wherein the resin composition is a reaction product of the compound (B-2). 4. The resin composition for a radiation dosimeter according to claim 1, wherein the polymerizable polymer (B) is water-soluble. 5. A phantom comprising the resin composition for a radiation dosimeter according to any one of claims 1 to 4. 6. A radiation dosimeter resin composition and a cured product of a phantom according to any one of claims 1 to 5. 7. A compound (A) capable of forming a gel, a polymer (B-1) having one or more epoxy groups in one molecule, and one compound having an ethylenically unsaturated double bond and a carboxyl group in one molecule.
Resin composition comprising, as constituents, a polymerizable polymer (B) obtained by the reaction of compound (B-2) having one by one and a solvent (C) containing water