WO2020246229A1 - Radiation dosimetry gel and radiation dosimeter provided with same as material for measuring radiation dose - Google Patents

Abstract

[Problem] To provide a radiation dosimetry gel and a radiation dosimeter provided with the same as material for measuring a radiation dose.　A radiation dosimetry gel including a water-soluble polymer (A) that undergoes coloration due to a radiolysis product, and a hydrogel (B).

Description

Radiation dosimetry gel and radiation dosimeter equipped with it as a radiation dose measurement material

The present invention relates to a radiation dosimetry gel and a radiation dosimeter provided with the gel as a radiation dose measurement material. More specifically, the present invention relates to a radiation dosimetry gel used for measuring a three-dimensional dose distribution, and a radiation dosimeter provided with the gel as a radiation dose measurement material.

The gel dosimeter is a three-dimensional dosimeter that utilizes a radiation-induced chemical reaction. The reaction products retained in the gel after irradiating the gel dosimeter with radiation are read by a three-dimensional scanner such as a magnetic resonance imaging (MRI) or optical CT (OCT) and converted into a dose distribution. Will be done. Since most of the gel is water and has a composition close to that of a living body, it is expected to be used as a verification tool for a complicated three-dimensional dose distribution planned especially in radiotherapy.
As a typical gel dosimeter capable of measuring a three-dimensional dose distribution, a flicke gel dosimeter, a polymer gel dosimeter, and the like are known. The Fricke gel dosimeter is a gelled solution of the Fricke dosimeter known as a liquid chemical dosimeter (an aqueous solution containing ferrous sulfate), and is a divalent to trivalent iron oxidation reaction (divalent to trivalent) associated with irradiation. It utilizes the fact that (coloring) increases in proportion to the absorbed dose. On the other hand, the polymer gel dosimeter is one in which a monomer is dispersed in a gel, and utilizes the fact that a polymer is produced in proportion to the dose (polymerization reaction) when irradiated with radiation (Patent Document 1).

In recent years, gel dosimeters using dyes have been widely reported (Patent Document 2, Non-Patent Documents 1 to 4). For example, the mechanism of radiation-induced color change of leuco crystal violet (LCV) used as a dye is shown below.

Further, as a radiation dosimeter using a radiochromic compound, a system in which diffusion is suppressed by using micelles of a dye compound and a surfactant has been reported (Non-Patent Documents 1 to 4).

U.S. Pat. No. 5,321,357 European Patent Application Publication No. 2546679

However, when a radiochromic compound is used, there is a problem that the solubility of the dye compound in water is low and it is difficult to obtain a stable hydrogel unless the dye compound is made into micelles with a surfactant.
Further, in the systems described in Non-Patent Documents 1 to 4, it is difficult to adjust the addition amount and addition method of each component at the time of producing the composition, control of micelle formation of the dye compound cannot be obtained, and storage stability is not obtained. There is a problem that it has a great influence on sex.

Therefore, an object of the present invention is to provide a stable radiation dosimetry gel that can be easily produced without the step of micellarizing a dye compound with a surfactant.
Another object of the present invention is to provide a radiation dosimeter capable of suppressing the diffusion of a water-soluble polymer colored after irradiation with radiation and allowing a long time for analysis after irradiation of the dosimeter.

As a result of intensive research to solve the above problems, the present inventors used a water-soluble polymer colored by a radiolysis product, for example, a water-soluble polymer containing a group derived from a leuco compound and a hydrogel. The present invention was completed by finding a radiation dose measurement gel that had been used.

That is, the present invention relates to a radiation dosimetry gel containing, as a first aspect, a water-soluble polymer (A) and a hydrogel (B) that are colored by a radiolysis product.
As a second aspect, the radiation dosimeter gel according to the first aspect, further comprising the organic halogen compound (C).
As a third aspect, the radiation dosimetry gel according to the first or second aspect, wherein the water-soluble polymer (A) contains a group derived from a leuco compound. ..
As a fourth viewpoint, the water-soluble polymer (A) is based on the following formula (A-1):

(In the above formula (A-1),
Ar is

Represents
A ₁ represents a single bond, -COO-, -OCO-, -NR _1- or -O-
p is 0 when A ₁ represents a single bond, and is an integer of 1 to 12 when A ₁ represents -COO-, -OCO-, -NR _1- or -O-.
R ₁ is independently a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, a sulfoalkyl group having 1 to 6 carbon atoms, and 2 to 7 carbon atoms. Carboxyalkyl group, cyanoalkyl group having 2 to 7 carbon atoms, alkoxyalkyl group having 2 to 6 carbon atoms, halogenoalkyl group having 1 to 6 carbon atoms, phenyl group having or unsubstituted substituent, or or represents a or unsubstituted benzyl group substituents, or R ₁ together may have to form a 3 to 10-membered ring together with the nitrogen atom attached, X ₁ and X ₂ are, each independently,

(In the above formula, R ₁ has the same meaning as above, and R ₂ independently represents a hydrogen atom, a methyl group or a phenyl group).
X ₃ represents a water-soluble group
Q represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a heteroatom, and when the total number of repeating units constituting the water-soluble polymer (A) is 1, the water-soluble polymer (Q) The ratios n and m of the repeating units in the formula (A-1) constituting A) are numbers that satisfy 0 <n ≦ 0.5, 0 <m ≦ 1, and m + n ≦ 1. )
The radiation dosimetry gel according to any one of the first aspect to the third aspect, which is represented by.
As a fifth viewpoint, the water-soluble polymer (A) is based on the following formula (A-2):

(In the above formula (A-2),
Ar is

Represents
A ₁ represents a single bond, -COO-, -OCO-, -NR _1- or -O-.
A ₂₁ represents -O- or -NR _1-
p is 0 when A ₁ represents a single bond, and represents an integer from 1 to 12 when A ₁ represents -COO-, -OCO- or -O-.
r represents an integer of 1 or 2
q represents an integer from 1 to 50
R ₁ represents an alkyl group having 1 to 6 carbon atoms.
R ₂ and R ₃ independently represent a hydrogen atom or a methyl group, respectively.
R ₄ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Q represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a heteroatom, and when the total number of repeating units constituting the water-soluble polymer (A) is 1, the water-soluble polymer (Q) The ratios n and m of the repeating units in the formula (A-1) constituting A) are numbers that satisfy 0 <n ≦ 0.5, 0 <m ≦ 1, and m + n ≦ 1. )
The gel relates to the radiation dosimetry according to any one of the first to fourth viewpoints represented by.
As a sixth aspect, the hydrogel (B) relates to the radiation dosimetry gel according to any one of the first to fifth aspects, which is selected from gelatin, agarose or gellan gum.
As a seventh aspect, the hydrogel (B) is a water-soluble organic polymer (A1) having an organic acid salt structure or an organic acid anion structure, a silicate (B1), and a dispersant (C1) of the silicate. The radiation dose measuring gel according to any one of the first to fifth aspects including.
As the eighth aspect, the present invention relates to a radiation dosimeter provided with the radiation dosimetry gel according to any one of the first to seventh aspects as a radiation dose measurement material.

According to the present invention, by using a water-soluble polymer that is colored by a radiolysis product, a simple step does not require a step of micellization of a dye compound and a surfactant when producing a radiation dosimetry gel. Can easily provide a radiation dosimetry gel.
Further, according to the present invention, the water-soluble polymer colored by the radiation decomposition product has good solubility in water and high compatibility with hydrogel, so that separation and precipitation of the water-soluble polymer can be suppressed. , A stable radiation dosimetry gel having excellent storage stability can be provided.
Further, according to the present invention, the water-soluble polymer colored by the radiolysis product suppresses the diffusion into the gel more than the low molecular weight dye compound or its micelles. Therefore, according to the present invention, the radiation dose It is possible to provide a radiation dosimeter equipped with a radiation dosimetry gel that can take a long time for post-irradiation analysis of the meter.

It is a figure which shows the result of the absorbance spectrum measurement of the radiation dosimetry gel of Example 1 to Example 4 irradiated with x-ray radiation (30 Gy). It is a figure which shows the increase amount of the absorbance with respect to the radiation irradiation amount of the radiation dosimeter of Examples 1 to 4. It is the schematic which shows the diffusion evaluation test method of the dosimeter gel of Example 6. It is the schematic which shows the preparation method of the reference sample of Example 6. It is a figure which shows the time-dependent change of the absorbance of the radiation dosimetry gel (trichloroacetic acid-containing gelatin sample) of Example 6 and Comparative Example 1.

[Radiation dosimetry gel]
Examples of the components of the radiation dosimetry gel of the present invention include a water-soluble polymer (A) and a hydrogel (B) that are colored by a radiolysis product. In addition to the above components, the intended effects of the present invention can be obtained. If necessary, other ingredients may be optionally blended as long as they are not impaired.

<Component (A): Water-soluble polymer colored by radiolysis products>
The radiation dosimetry gel of the present invention contains a water-soluble polymer (A) that is colored by a radiolysis product, so that the radiation dosimeter equipped with the radiation dosimetry gel of the present invention as a radiation dose measurement material is a fluorescent gel. Functions as a dosimeter.

Examples of the water-soluble polymer (A) colored by the radiolysis product include a water-soluble polymer having a structure in which the main chain or side chain reacts with the radiolysis product to develop or discolor. In particular, a water-soluble polymer having a structure in the side chain that develops or discolors by reacting with a radiolysis product is preferable.
Examples of the radiolysis product include those produced by irradiating the hydrogel with radiation, and examples thereof include active oxygen species such as hydroxyl radical and superoxide radical, which are radiolysis products of water in the hydrogel. In addition, the radiolysis product also includes a radiolysis product of other components contained in the hydrogel, for example, a radiolysis product (halogen radical) of an organic halogen compound described later.
Since the water-soluble polymer (A) develops or discolors when irradiated with radiation, the hydrogel containing the water-soluble polymer (A) can easily detect the presence or absence of irradiation of the hydrogel by the color development or discoloration. Is.

A group derived from a leuco compound is preferable as a structure that develops or discolors due to a radiolysis product.
As the leuco compound, a conventionally known leuco compound or a precursor compound thereof can be used.
For example, but not limited to these, triphenylmethanephthalides, fluorans, phenothiazines, phenazines, indolylphthalides, leukooramines, spiropirans, spiroftalans, spironaftoxazines, Leuco compounds such as naphthopirans, rhodamine lactams, rhodamine lactones, indolins, diphenylmethanes, triphenylmethanes, azaphthalides, triazenes, clomenoindoles, xanthenes, diacetylene, naphtholactams and azomethines Examples thereof include leuco compounds of triphenylmethanes, diphenylbiphenylmethanes and diphenylnaphthylmethanes, and leuco compounds of triphenylmethanes are particularly preferable.

Specific examples of the leuco compound include, but are not limited to, the compound represented by the following formula (I).

(In the formula (I), Ar and _{R 1} are as defined above, _{A 3} is -COO -, - OCO -, - NR 1 - or an -O-.)

Examples of the water-soluble polymer containing a group derived from a leuco compound in the side chain include a water-soluble polymer represented by the following formula (A-1).

In formula (A-1), Ar is

Represents.
In formula (A-1), A ₁ represents a single bond, -COO-, -OCO- or -O-.
In formula (A-1), p is 0 when A ₁ represents a single bond, and when A ₁ represents a single bond, -COO-, -OCO-, -NR _1- or -O-. P is 1 to 12. Preferably p is an integer of 1-6.
In the formula (A-1), R ₁ is independently a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, and a sulfoalkyl having 1 to 6 carbon atoms. It has a group, a carboxyalkyl group having 2 to 7 carbon atoms, a cyanoalkyl group having 2 to 7 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, a halogenoalkyl group having 1 to 6 carbon atoms, and a substituent. or unsubstituted phenyl group, or represent a having or unsubstituted benzyl group substituents, or represents a 3 to that may form a 10-membered ring together with the nitrogen atom to which R ₁ are bonded to each other.
In formula (A-1), X ₁ and X ₂ are independent of each other.

(In the formula, R ₁ has the same meaning as above, and R ₂ independently represents a hydrogen atom or a methyl group.)
Represents.
Wherein (A-1), _{X 3} represents a water-soluble group.
Q represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a heteroatom. The term "may be interrupted by a heteroatom" means that the main chain or side chain of the above alkyl group contains an -O- or -S- bond.
Examples of the alkylene group having 1 to 10 carbon atoms include methylene group, ethylene group, n-propylene group, isopropylene group, cyclopropylene group, n-butylene group, isobutylene group, s-butylene group, t-butylene group and cyclo. Butylene group, 1-methyl-cyclopropylene group, 2-methyl-cyclopropylene group, n-pentylene group, 1-methyl-n-butylene group, 2-methyl-n-butylene group, 3-methyl-n-butylene group , 1,1-dimethyl-n-propylene group, 1,2-dimethyl-n-propylene group, 2,2-dimethyl-n-propylene, 1-ethyl-n-propylene group, cyclopentylene group, 1-methyl -Cyclobutylene group, 2-methyl-cyclobutylene group, 3-methyl-cyclobutylene group, 1,2-dimethyl-cyclopropylene group, 2,3-dimethyl-cyclopropylene group, 1-ethyl-cyclopropylene group, 2 -Ethyl-cyclopropylene group, n-hexylene group, 1-methyl-n-pentylene group, 2-methyl-n-pentylene group, 3-methyl-n-pentylene group, 4-methyl-n-pentylene group, 1, 1-Dimethyl-n-butylene group, 1,2-dimethyl-n-butylene group, 1,3-dimethyl-n-butylene group, 2,2-dimethyl-n-butylene group, 2,3-dimethyl-n- Butylene group, 3,3-dimethyl-n-butylene group, 1-ethyl-n-butylene group, 2-ethyl-n-butylene group, 1,1,2-trimethyl-n-propylene group, 1,2,2 -Trimethyl-n-propylene group, 1-ethyl-1-methyl-n-propylene group, 1-ethyl-2-methyl-n-propylene group, cyclohexylene group, 1-methyl-cyclopentylene group, 2-methyl -Cyclopentylene group, 3-methyl-cyclopentylene group, 1-ethyl-cyclobutylene group, 2-ethyl-cyclobutylene group, 3-ethyl-cyclobutylene group, 1,2-dimethyl-cyclobutylene group, 1 , 3-dimethyl-cyclobutylene group, 2,2-dimethyl-cyclobutylene group, 2,3-dimethyl-cyclobutylene group, 2,4-dimethyl-cyclobutylene group, 3,3-dimethyl-cyclobutylene group, 1 -N-propyl-cyclopropylene group, 2-n-propyl-cyclopropylene group, 1-isopropyl-cyclopropylene group, 2-isopropyl-cyclopropylene group, 1,2,2-trimethyl-cyclopropylene group, 1,2 , 3-trimethyl-cyclopropylene group, 2,2,3-to Limethyl-cyclopropylene group, 1-ethyl-2-methyl-cyclopropylene group, 2-ethyl-1-methyl-cyclopropylene group, 2-ethyl-2-methyl-cyclopropylene group, 2-ethyl-3-methyl- Cyclopropylene group, n-heptylene group, n-octylene group, n-nonylene group or n-decanylen group can be mentioned.

The water-soluble polymer containing a group derived from the leuco compound in the side chain may be, for example, a water-soluble polymer represented by the following formula (A-3).

In the above formula (A-3), Ar, A ₁ , X ₁ , X ₂ , X ₃ , Q, n, m and p have the same meanings as above, and k represents an integer of 1 to 8.

Further, when the total number of repeating units constituting the water-soluble polymer (A) is 1, the ratios n and m of the repeating units of the formula (A-1) constituting the water-soluble polymer (A) are 0 <. It is a number that satisfies n ≦ 0.5, 0 <m ≦ 1, and m + n ≦ 1.
From the viewpoint of improving the solubility of the water-soluble polymer (A) in hydrogel or the reactivity of the radiolysis product, n and m are 0 <n ≦ 0.4 and 0 <m ≦ 1, respectively. It is preferable that the number satisfies m + n ≦ 1, and more preferably 0.05 <n ≦ 0.3, 0 <m ≦ 1, and m + n ≦ 1.
When n is a number exceeding 0.5, the compatibility of the water-soluble polymer (A) with respect to the hydrogel deteriorates, the hydrogel is not uniformly dispersed in the water-soluble polymer, or precipitation occurs during long-term storage. Storage stability may deteriorate.

The alkyl group having 1 to 30 carbon atoms in R ₁ may be linear, branched or cyclic, preferably having 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. ..
Specifically, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, 1-methylpropyl group, isobutyl group, tert-butyl group, pentyl group, 1-ethylpropyl group, 1-methylbutyl group, Cyclopentyl group, hexyl group, 1-methylpentyl group, 1-ethylbutyl group, cyclohexyl group, 2-heptyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group , Pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadesyl group, eikosyl group, henicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, isoheptyl Group, Isooctyl group, Isononyl group, Isodecyl group, Isoundecyl group, Isododecyl group, Isotridecyl group, Isotetradecyl group, Isopentadecyl group, Isohexadecyl group, Isoheptadecyl group, Isooctadecyl group, Isononadecyl group, Isoaraquil group, Isoeicosyl group , Isohenicosyl group, Isodocosyl group, Isotricosyl group, Isotetracosyl group, Isopentacosyl group, Isohexacosyl group, Isoheptacosyl group, Isooctacosyl group, Isononacosyl group, Isotriacontyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-methylheptyl group. Group, 1-cyclohexylethyl group, 1-heptyloctyl group, 2-methylcyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 2,6-dimethylcyclohexyl group, 2,4-dimethyl Cyclohexyl group, 3,5-dimethylcyclohexyl group, 2,5-dimethylcyclohexyl group, 2,3-dimethylcyclohexyl group, 3,3,5-trimethylcyclohexyl group, 4-tert -Butylcyclohexyl group, 2-ethylhexyl group, 1-adamantyl group, 2-adamantyl group and the like can be mentioned, with methyl group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group, hexyl group and the like being preferable, and methyl group. A group, an ethyl group, a propyl group and the like are more preferable.

The hydroxyalkyl group having 1 to 6 carbon atoms in R ₁ is preferably one having 1 to 3 carbon atoms, and specifically, for example, a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, or a hydroxybutyl group. , Hydroxypentyl group, hydroxyhexyl group and the like.
The sulfoalkyl group having 1 to 6 carbon atoms in R ₁ is preferably one having 1 to 3 carbon atoms. Specifically, for example, a sulfomethyl group, a sulfoethyl group, a sulfopropyl group, a sulfobutyl group, and the like. Examples thereof include a sulfopentyl group and a sulfohexyl group.

The carboxyalkyl group having a carbon number of 2 to 7 in the R _1, preferably having a carbon number of 3 to 6, specifically, for example, carboxymethyl group, carboxyethyl group, carboxypropyl group, carboxybutyl group , Carboxypentyl group, carboxyhexyl group and the like, and carboxyethyl group is preferable.
Further, as the cyanoalkyl group having 2 to 7 carbon atoms in R ₁ , those having 2 to 4 carbon atoms are preferable, and specifically, for example, a cyanomethyl group, a cyanoethyl group, a cyanopropyl group, a cyanobutyl group, and the like. Examples thereof include a cyanopentyl group and a cyanohexyl group, and a cyanoethyl group is preferable.

The alkoxyalkyl group having 2 to 6 carbon atoms in R ₁ is preferably one having 3 to 5 carbon atoms, and specifically, for example, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, or an ethoxyethyl group. , Propoxymethyl group, propoxyethyl group, butoxymethyl group, butoxyethyl group and the like.
Further, as the halogenoalkyl group having 1 to 6 carbon atoms in R ₁ , those having 1 to 3 carbon atoms are preferable, and specifically, for example, a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl, and the like. Examples thereof include a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

The phenyl group or benzyl group having a substituent in R ₁ has 1 to 5, preferably 1 to 3 substituents in the benzene ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group and a hexyl group; a fluorine atom. , Halogen atoms such as chlorine atom, bromine atom, iodine atom; sulfo group; methoxy group, ethoxy group, propoxy group, butoxy group, tert-butoxy group, propoxy group, hexyloxy group and other alkoxy having 1 to 6 carbon atoms. Group; hydroxyalkyl group having 1 to 6 carbon atoms such as hydroxyethyl group and hydroxypropyl group; alkoxyalkyl group having 2 to 10 carbon atoms such as methoxyethyl group, ethoxyethyl group, ethoxypropyl group and butoxyethyl group; A hydroxyalkoxy group having 1 to 6 carbon atoms such as a 2-hydroxyethoxy group; an alkoxyalkoxy group having 2 to 10 carbon atoms such as a 2-methoxyethoxy group and a 2-ethoxyethoxy group; a carbon atom such as a 2-sulfoethyl group. Number 1 to 6 sulfoalkyl groups; carboxyalkyl groups having 2 to 7 carbon atoms such as carboxymethyl group, carboxyethyl group, carboxypropyl group, carboxybutyl group, carboxypentyl group, carboxyhexyl group; cyanomethyl group, cyanoethyl group , A cyanoalkyl group having 2 to 7 carbon atoms such as a cyanopropyl group, a cyanobutyl group, a cyanopentyl group and a cyanohexyl group.

In the R _1, 3 to 10-membered ring formed together with the nitrogen atom to which R ₁ are bonded to each other is preferably from 3 to 8-membered ring, preferably 4 to 6-membered ring, preferably a 5- or 6-membered ring Specific examples thereof include an aziridine ring, an azetidine ring, a pyrrolidine ring, a piperidine ring, an azepane ring, and an azocane ring. Further, the formed ring may have the above-mentioned substituent.

Among the specific examples of R ₁ , hydrogen atom, methyl group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group, hexyl group and the like are preferable, and hydrogen atom, methyl group, ethyl group, propyl group and the like are more preferable. Preferably, an ethyl group is particularly preferred.

Examples of the water-soluble group include an alkyl group having one or more substituents selected from a hydroxy group, a carboxyl group and an amino group, a polyethylene glycol ester structure, a polypropylene glycol ester structure, a polytrimethylene glycol ester structure and the like. Examples thereof include an organic group having one or more types of structures selected from a hydroxyalkyl ester structure having 2 to 5 carbon atoms, preferably a polyethylene glycol ester structure, a polypropylene glycol ester structure, a polytrimethylene glycol ester structure, and the like. / Or a hydroxyalkyl ester structure having 2 to 5 carbon atoms can be mentioned, and more preferably, a polyethylene glycol ester structure and / or a polytrimethylene glycol ester structure can be mentioned.

The water-soluble polymer (A) of the present invention is preferably represented by the following formula (A-2).

In formula (A-2), Ar, A ₁ , p, n and m have the same meanings as described above.
In formula (A-2), A ₂₁ represents -O- or -NR _1- .
In formula (A-2), r is an integer of 1 or 2.
In formula (A-2), q is an integer of 1 to 50, preferably an integer of 10 to 50.
In the formula (A-2), R ₁ represents an alkyl group having 1 to 6 carbon atoms.
In formula (A-2), R ₂ and R ₃ independently represent a hydrogen atom or a methyl group, respectively.
In the formula (A-2), R ₄ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Here, specific examples of the alkyl group having 1 to 6 carbon atoms and the alkyl group having 1 to 3 carbon atoms are the same as those described above.
In formula (A-2), Q represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a heteroatom.

The weight average molecular weight of the water-soluble polymer (A) of the present invention is not particularly limited as long as the water-soluble polymer can be uniformly dissolved or dispersed in the hydrogel, but is, for example, 5,000 to 100. It is 10,000, preferably 10,000 to 500,000, and more preferably 10,000 to 100,000.
If the weight average molecular weight exceeds 1 million, the solubility in hydrogel may decrease, the handleability may deteriorate, or the solution or dispersion may not be uniform. On the other hand, if the average molecular weight of the polymerization is less than 5,000, the water-soluble polymer (A) may emerge on the surface of the hydrogel after long-term storage, or it may be difficult to suppress the diffusion of the colored water-soluble polymer.
In the present invention, the weight average molecular weight is a polystyrene-equivalent measurement value by gel permeation chromatography (GPC).

Further, the water-soluble polymer (A) of the present invention may contain other repeating units in addition to the formula (A-1) or the formula (A-2) as long as the effects of the present invention are not impaired. Other repeating units include, for example, acrylic acid ester compounds such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl methacrylate, butyl acrylate, isobutyl acrylate, t-butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and the like. Methacrylate compounds such as isopropyl methacrylate, isobutyl methacrylate and t-butyl methacrylate, maleimide compounds such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide, acrylamide compounds, acrylonitrile, maleic anhydride, styrene. It is a repeating unit produced by the polymerization of compounds and vinyl compounds.
The content ratio of the other repeating units may be as long as the desired effect of the present invention is not impaired. For example, when the total number of repeating units constituting the water-soluble polymer (A) is 1, 0.2. It is less than or equal to, preferably 0.1 or less.
When the content ratio of the other repeating unit exceeds 0.2, the reactivity of the water-soluble polymer (A) with the radiolysis product decreases, or the solubility of the water-soluble polymer (A) in hydrogel becomes low. It may decrease.

Further, the water-soluble polymer (A) of the present invention can be used alone or in combination of two or more.

<Synthesis of water-soluble polymer (A)>
The water-soluble polymer (A) of the present invention can be produced, for example, by reacting the leuco compound with a water-soluble polymer having a group capable of reacting with a group in the leuco compound.
Further, for example, a group derived from a leuco compound, a water-soluble group, and a group obtained by reacting the leuco compound with a group capable of reacting with a group in the leuco compound, a water-soluble group, and a polymerizable compound having a polymerizable group. By polymerizing a polymerizable compound having a polymerizable group, a water-soluble polymer that is colored by a radiation decomposition product can be produced.
Further, for example, a water-soluble weight colored by a radiolysis product by copolymerizing a polymerizable compound having a group derived from the leuco compound and a polymerizable group and a polymerizable compound having a water-soluble group and a polymerizable group. Coalescence can be manufactured.
In particular, a water-soluble polymer colored by a radiolysis product obtained by polymerizing a polymerizable compound having a group derived from the leuco compound and a polymerizable group and a polymerizable compound having a water-soluble group and a polymerizable group. Is preferable.

Examples of the polymerizable group include a group containing a polymerizable ethylenically unsaturated group. For example, acrylic acid, methacrylic acid, 2-phenylacrylic acid, a group derived from maleimide or a group derived from α-methylene-γ-butyrolactone can be mentioned, and an acrylic group or a methacrylic group is preferable.

The leuco compound and the polymerizable group are bonded either directly or via a linking group.
Examples of the linking group include -O-, -OCO-, -COO-, -NR _1- , an alkylene group having 1 to 21 carbon atoms, or a combination thereof.
Examples of the alkylene group having 1 to 21 carbon atoms include methylene group, ethylene group, n-propylene group, isopropylene group, cyclopropylene group, n-butylene group, isobutylene group, s-butylene group, t-butylene group and cyclo. Butylene group, 1-methyl-cyclopropylene group, 2-methyl-cyclopropylene group, n-pentylene group, 1-methyl-n-butylene group, 2-methyl-n-butylene group, 3-methyl-n-butylene group , 1,1-dimethyl-n-propylene group, 1,2-dimethyl-n-propylene group, 2,2-dimethyl-n-propylene, 1-ethyl-n-propylene group, cyclopentylene group, 1-methyl -Cyclobutylene group, 2-methyl-cyclobutylene group, 3-methyl-cyclobutylene group, 1,2-dimethyl-cyclopropylene group, 2,3-dimethyl-cyclopropylene group, 1-ethyl-cyclopropylene group, 2 -Ethyl-cyclopropylene group, n-hexylene group, 1-methyl-n-pentylene group, 2-methyl-n-pentylene group, 3-methyl-n-pentylene group, 4-methyl-n-pentylene group, 1, 1-Dimethyl-n-butylene group, 1,2-dimethyl-n-butylene group, 1,3-dimethyl-n-butylene group, 2,2-dimethyl-n-butylene group, 2,3-dimethyl-n- Butylene group, 3,3-dimethyl-n-butylene group, 1-ethyl-n-butylene group, 2-ethyl-n-butylene group, 1,1,2-trimethyl-n-propylene group, 1,2,2 -Trimethyl-n-propylene group, 1-ethyl-1-methyl-n-propylene group, 1-ethyl-2-methyl-n-propylene group, cyclohexylene group, 1-methyl-cyclopentylene group, 2-methyl -Cyclopentylene group, 3-methyl-cyclopentylene group, 1-ethyl-cyclobutylene group, 2-ethyl-cyclobutylene group, 3-ethyl-cyclobutylene group, 1,2-dimethyl-cyclobutylene group, 1 , 3-dimethyl-cyclobutylene group, 2,2-dimethyl-cyclobutylene group, 2,3-dimethyl-cyclobutylene group, 2,4-dimethyl-cyclobutylene group, 3,3-dimethyl-cyclobutylene group, 1 -N-propyl-cyclopropylene group, 2-n-propyl-cyclopropylene group, 1-isopropyl-cyclopropylene group, 2-isopropyl-cyclopropylene group, 1,2,2-trimethyl-cyclopropylene group, 1,2 , 3-trimethyl-cyclopropylene group, 2,2,3-to Limethyl-cyclopropylene group, 1-ethyl-2-methyl-cyclopropylene group, 2-ethyl-1-methyl-cyclopropylene group, 2-ethyl-2-methyl-cyclopropylene group, 2-ethyl-3-methyl- Cyclopropylene group, n-heptylene group, n-octylene group, n-nonylene group or n-decanylen group can be mentioned.

Examples of the polymerizable compound having a group derived from a leuco compound and a polymerizable group include polymerizable compounds represented by the following formulas (a-1) to (a-3), preferably the following formula (a-). Examples thereof include the compound represented by 1).

In formula (a-1), R ₁ , Ar, A ₁ , A ₂₁ , p and Q have the same meanings as above, and R ₁₀ represents a hydrogen atom, a methyl group or a phenyl group.
Wherein (a-2) and _{(a-3), R 1} , Ar, A 1, A 21, p and Q are as defined above.

The polymerizable compound represented by the formula (a-1) is produced by sequentially performing the following reactions [Step 1] and [Step 2].
[Step 1]: A compound represented by the following formula (I-1) is reacted with a compound represented by the following formula (I-2) to synthesize a leuco compound represented by the formula (I).
[Step 2]: A leuco compound represented by the formula (I) is reacted with a compound represented by the formula (I-3) to obtain a polymerizable compound represented by the formula (a-1).

(In the formula, R ₁ , Ar, A ₁ , A ₂₁ , A ₃ , p, R ₁₀ and Q have the same meanings as above.)

The above reaction [step 1] can be carried out by a known method, and as the reaction conditions, for example, a compound represented by the formula (I-1) and a compound represented by the formula (I-2) are mixed in a solvent. The reaction can be carried out at 80 to 150 ° C., preferably 100 to 130 ° C., usually 1 to 24 hours, preferably 5 to 15 hours in the presence of an acid catalyst.
Examples of the acid catalyst include sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, paratoluenesulfonic acid, camphorsulfonic acid and the like, and paratoluenesulfonic acid is preferable. The amount of the acid catalyst used is usually 0.1 to 10 equivalents, preferably 0.5 to 2 equivalents, relative to the number of moles of the compound represented by the formula (I-1).
Examples of the solvent include ketones such as diethyl ketone and methyl isobutyl ketone (MIBK), and organic solvents such as ethers such as diisopropyl ether, and among them, MIBK is preferable. These may be used alone or in combination of two or more as appropriate. The amount of the reaction solvent used is usually 1 to 20 times, preferably 1 to 5 times, the total weight of the compound represented by the formula (I-1) and the compound represented by the formula (I-2). is there.

The amount of the compound represented by the formula (I-2) used is usually 2 to 6 equivalents, preferably 2 to 4 equivalents, relative to the number of moles of the compound represented by the formula (I-1).

Specific examples of the compound represented by the formula (I-1) include 2-formylbenzoic acid, 3-formylbenzoic acid, 4-formylbenzoic acid, 2-formylphenol, 3-formylphenol, 4-formylphenol and the like. Can be mentioned.

Examples of the compound represented by the formula (I-2) include N-methylaniline, N-ethylaniline, N-propylaniline, N-butylaniline, N-pentylaniline, N-hexylaniline, N, N-. Dimethylaniline, N, N-diethylaniline, N, N-dipropylaniline, N, N-butylaniline, N, N-dipentylaniline, N, N-dihexylaniline, 1-phenylaziridine, 1-phenylazetidine, Examples thereof include 1-phenylpyrrolidine, 1-phenylpiperidin, 1-phenylazepan, 1-phenylazocan and the like, preferably N, N-dimethylaniline, N, N-diethylaniline and N, N-dipropylaniline. N, N-diethylaniline is more preferable.

In the above reaction [step 1], wherein when using a different two compounds radicals R ₁ as compounds represented by (I-2), firstly the formula (I-1) and one of the formula (I-2) The compound represented by (1) can be reacted 1: 1 and the reaction product obtained thereafter can be reacted with the other compound represented by the formula (I-2). The reaction conditions (reaction solvent, acid catalyst, reaction temperature, reaction time, each amount used) in this case are all the same reaction conditions as those in the above-mentioned reaction [step 1].

In the above reaction [step 2], the compound represented by the formula (I) and the compound represented by the formula (I-3) are usually mixed at 0 to 80 ° C., preferably 0 to 80 ° C. in a solvent in the presence of a dehydration condensing agent. The reaction may be carried out at 10 to 50 ° C. for usually 1 to 24 hours, preferably 3 to 18 hours.
Examples of the solvent include ethers such as diethyl ether, diisopropyl ether, ethyl methyl ether, tetrahydrofuran, 1,4-dioxane and dimethoxyethane; for example, acetone, dimethyl ketone, methyl ethyl ketone, diethyl ketone, 2-hexanone, tert-butyl methyl ketone, etc. Ketones such as cyclopentanone and cyclohexanone; for example halogenated hydrocarbons such as chloromethane, chloroform, dichloromethane, dichloroethane, trichloroethane, carbon tetrachloride, chlorobenzene; for example, hydrocarbons such as n-hexane, benzene, toluene, xylene Examples include esters such as ethyl acetate, butyl acetate and methyl propionate; nitriles such as acetonitrile; amides such as N, N-dimethylformamide and the like, among which ethers, halogenated hydrocarbons and carbides. Hydrogens are preferable, and tetrahydrofuran, toluene and methylene chloride are more preferable. These solvents may be used alone or in combination of two or more.
The amount of the reaction solvent used is usually 1 to 50 times, preferably 5 to 10 times, the total weight of the compound represented by the formula (I) and the compound represented by the formula (I-3).

The dehydration condensing agent is not particularly limited as long as it is used for ordinary ester synthesis, but for example, Mukaiyama reagent (2-chloro-N-methylpyridinium iodide), DCC (1,3-dicyclohexylcarbodiimide). , EDC (1-ethyl-3- (3-dimethylaminopropyl) -carbodiimide hydrochloride), CDI (carbonyldiimidazole), dimethylpropynylsulfonium bromide, propargyltriphenylphosphonium bromide, DEPC (diethyl cyanophosphate) and the like can be used. ..
The amount of the dehydration condensing agent used is 1 to 20 equivalents, preferably 1 to 10 equivalents, preferably 1 to 5 equivalents, relative to the leuco compound represented by the formula (I).
In the method of reacting the leuco compound represented by the above formula (I) with the compound represented by the general formula (I-3), a catalyst such as dimethylaminopyridine is used in order to improve the efficiency of the dehydration condensing agent. You may use it. The amount of the catalyst used is 0.1 to 10 equivalents with respect to the compound represented by the general formula (I-3).

It is not always necessary to add a base, but when a base is used, for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate. Alkali metal bicarbonate, triethylamine, tributylamine, N, N-dimethylaniline, pyridine, 4- (dimethylamino) pyridine, imidazole, 1,8-diazabicyclo [5,4,0] -7-undecene, etc. 1 to 4 equivalents of an organic base or the like can be used with respect to the compound represented by the formula (I-3). Pyridine and 4- (dimethylamino) pyridine are preferred because the reaction proceeds mildly.

The amount of the compound represented by the formula (I-3) used is usually 1 to 2 equivalents, preferably 1 to 1.5 equivalents, relative to the number of moles of the compound represented by the formula (I).

Preferred specific examples of the compound represented by the formula (I-3) include, for example, the following.

A maleimide-based polymerizable compound (a-2) can be obtained by using, for example, the compounds listed below instead of the compound represented by the formula (I-3).

The α-methylene-γ-butyrolactone-based polymerizable compound (a-3) can be obtained by using, for example, the compounds listed below instead of the compound represented by the formula (I-3).

The water-soluble group and the polymerizable group of the polymerizable compound having the water-soluble group and the polymerizable group are the above-mentioned water-soluble group and the polymerizable group.
Known compounds can be used as the polymerizable compound having a water-soluble group and a polymerizable group. For example, HO- (CH ₂ (CH ₂ ) _r O) _q- R ₄ (where q, r and R ₄ are It has the same meaning as above.) Monoacrylate, monomethacrylate or 2-phenylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, Examples thereof include 4-hydroxybutyl methacrylate, acrylamide, methacrylamide and 2,5-dioxo-3-pyrrolin-3-carbamide. _{HO- (CH 2 (CH 2)} r O) q -R 4 of monoacrylate, monomethacrylate or 2-phenyl acrylate.
These can be used alone or in combination of two or more.

Further, in the synthesis of the water-soluble polymer of the present invention, other polymerizable compounds can be used in combination as long as the effects of the present invention are not impaired.
Examples of such polymerizable compounds include acrylic acid ester compounds such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl methacrylate, butyl acrylate, isobutyl acrylate and t-butyl acrylate, methyl methacrylate, ethyl methacrylate and propyl. Methacrylate compounds such as methacrylate, isopropyl methacrylate, isobutyl methacrylate and t-butyl methacrylate, maleimide compounds such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide, acrylamide compounds, acrylonitrile, maleic acid anhydride , Styrene compounds, vinyl compounds and the like.

A known method for producing a water-soluble polymer (A) by copolymerizing a polymerizable compound having a group and a polymerizable group derived from the leuco compound and a polymerizable compound having a water-soluble group and a polymerizable group. Can be used.
The method for synthesizing the water-soluble polymer (A) is not particularly limited, and radical polymerization, anionic polymerization, cationic polymerization and the like can be adopted. Of these, radical polymerization is particularly preferable, and specifically, the above-mentioned polymerizable compound may be heated in a solvent in the presence of a polymerization initiator to polymerize.
The obtained water-soluble polymer (A) can be purified by a known method such as recrystallization or reprecipitation, for example, in the form of a powder or in the form of a solution obtained by redissolving the purified powder in a solvent described later. Can be used.

As the above-mentioned polymerization initiator, conventionally known ones can be appropriately selected and used. For example, peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide; persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate; azobisisobutyronitrile (AIBN), azo Examples thereof include azo compounds such as bismethylbutyronitrile and azobisisobutyronitrile. These can be used alone or in combination of two or more.

The amount of the polymerization initiator used is preferably about 0.01 to 0.05 mol with respect to 1 mol of the polymerizable compound.
The reaction temperature may be appropriately set from 0 ° C. to the boiling point of the solvent used, but is preferably about 20 to 100 ° C. The reaction time is preferably about 0.1 to 30 hours.

The solvent used in the polymerization reaction is not particularly limited, and may be appropriately selected from various solvents generally used in the above-mentioned polymerization reaction. Specifically, water; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol, iso Alcohols such as pentanol, t-pentanol, 1-hexanol, 1-heptanol, 2-heptanol, 3-heptanol, 2-octanol, 2-ethyl-1-hexanol, benzyl alcohol, cyclohexanol; diethyl ether, diisopropyl Ethers such as ether, dibutyl ether, cyclopentyl methyl ether, tetrahydrofuran, 1,4-dioxane; halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, carbon tetrachloride; methyl cellosolve, ethyl cellosolve, isopropyl cellosolve, butyl cellosolve, diethylene glycol Ether alcohols such as monobutyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl propionate and cellosolve acetate; n-pentane, n-hexane and n-heptane. , N-octane, n-nonane, n-decane, cyclopentan, methylcyclopentan, cyclohexane, methylcyclohexane, benzene, toluene, xylene, ethylbenzene, anisole and other aliphatic or aromatic hydrocarbons; methylal, diethyl acetal, etc. Acetals; fatty acids such as formic acid, acetic acid, propionic acid; nitropropane, nitrobenzene, dimethylamine, monoethanolamine, pyridine, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide, dimethylsulfoxide, Examples thereof include acetonitrile. These can be used alone or in combination of two or more.

When the water-soluble polymer (A) contains the above other repeating units, the method for synthesizing the water-soluble polymer (A) may be to coexist and polymerize a polymerizable compound that gives the above other repeating units at the time of the above polymerization.

The water-soluble polymer (A) may be any of a random copolymer, an alternating copolymer, and a block copolymer.

<Component (B): Hydrogel>
As the hydrogel, known hydrogels can be used as long as the effects of the present invention are not impaired.
For example, a hydrogel containing a natural, semi-synthetic or synthetic polymer, or a water-soluble organic polymer (A1), a silicate (B1) having an organic acid salt structure or an organic acid anion structure, and a dispersant for the silicate ( Hydrogels containing C1) can be mentioned.
In addition to the above components, other components may be optionally added to the hydrogel as long as the desired effect of the hydrogel is not impaired.

Natural and semi-synthetic polymers include, for example, polysaccharides such as agarose, gellan gum, cellulose, starch, tragacant, gum arabic, xanthan gum, agar, gelatin, alginic acid and salts thereof, such as sodium alginate and its derivatives, lower alkyl cellulose, For example, methyl cellulose or ethyl cellulose, carboxy- or hydroxy-lower-alkyl cellulose, such as carboxymethyl cellulose or hydroxypropyl cellulose can be mentioned. The gellan gum referred to in the present invention may be either naturally derived or deacylated gellan gum. Examples of the synthetic gelling agent include polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid and the like. Preferred examples include agarose, gellan gum and gelatin. More preferably, gelatin is used.

Examples of the water-soluble organic polymer (A1) having an organic acid salt structure or an organic acid anion structure include poly (meth) acrylates, carboxyvinyl polymer salts, and carboxymethyl cellulose salts, as those having a carboxyl group. Examples of those having a sulfonyl group include polystyrene sulfonates; and those having a phosphonyl group include polyvinylphosphonates. Examples of the salt include sodium salt, ammonium salt, potassium salt, lithium salt and the like. In the present invention, the (meth) acrylic acid refers to both acrylic acid and methacrylic acid.

Further, the water-soluble organic polymer (A1) may be crosslinked or copolymerized, and either a completely neutralized product or a partially neutralized product can be used.

The weight average molecular weight of the water-soluble organic polymer (A1) is preferably 1 million to 10 million, more preferably 2 million to 7 million in terms of polyethylene glycol by gel permeation chromatography (GPC). ..
The water-soluble organic polymer available as a commercially available product preferably has a weight average molecular weight of 1 million to 10 million, and more preferably a weight average molecular weight of 2 million to 7 million, as described in the commercially available product.

The water-soluble organic polymer (A1) is preferably a water-soluble organic polymer compound having a carboxylate structure or a carboxy anion structure, and particularly preferably a completely neutralized or partially neutralized polyacrylate. .. Specifically, completely neutralized or partially neutralized sodium polyacrylate is preferable, and in particular, completely neutralized or partially neutralized non-crosslinked sodium polyacrylate having a weight average molecular weight of 2 to 7 million is preferable.

The content of the water-soluble organic polymer (A1) is 0.01% by mass to 20% by mass, preferably 0.1% by mass to 10% by mass in 100% by mass of hydrogel.

The silicate (B1) is preferably water-swellable silicate particles. Examples of the silicate (B1) include smectite, bentonite, vermiculite, mica and the like, and those that form a colloid using water or a hydrous solvent as a dispersion medium are preferable. In addition, smectite is a group name such as montmorillonite, byderite, nontronite, saponite, hectorite, and stephensite.
Examples of the shape of the primary particles of the silicate particles include a disk shape, a plate shape, a spherical shape, a granular shape, a cubic shape, a needle shape, a rod shape, an amorphous shape, and the like, and a disc shape or a plate shape having a diameter of 5 nm to 1000 nm is used. preferable.
A preferable specific example of the silicate (B1) is a layered silicate, and as an example easily available as a commercial product, Laponite manufactured by Rockwood Additives (registered by BWK Additives Limited). Trademarks) XLG (Synthetic Hectorite), XLS (Synthetic Hectorite, containing sodium pyrophosphate as a dispersant), XL21 (Sodium magnesium fluorosilicate), RD (Synthetic Hectorite), RDS (Synthetic Hectorite, as a dispersant) Inorganic polyphosphate contained), and S482 (synthetic hectorite, dispersant contained); Lucentite (registered trademark of Katakura Corp Agri Co., Ltd.) SWN (synthetic smectite) manufactured by Kunimine Kogyo Co., Ltd. (formerly Corp Chemical Co., Ltd.) and SWF (synthetic smectite), micromica (synthetic mica), and somasif (registered trademark of Katakura Corp. Agri Co., Ltd., synthetic mica); Kunipia manufactured by Kunimine Kogyo Co., Ltd. (registered trademark of Kunimine Kogyo Co., Ltd. SA (synthetic saponite) (registered trademark of Hojun Co., Ltd.); Bengel (registered trademark of Hojun Co., Ltd., refined natural bentonite product) manufactured by Hojun Co., Ltd.

The content of the silicate (B1) is 0.01% by mass to 20% by mass, preferably 0.1% by mass to 15% by mass in 100% by mass of the hydrogel.
Further, in the present invention, the silicate (B1) can be used alone or in combination of two or more.

The silicate dispersant (C1) is preferably a dispersant for water-swellable silicate particles.
As the silicate dispersant (C1), a dispersant or a glutinating agent used for the purpose of improving the dispersibility of the silicate and delaminating the layered silicate can be used.
Examples of the silicate dispersant (C1) include sodium orthorate, sodium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, sodium hexametaphosphate, and sodium polyphosphate as phosphate-based dispersants; As a system dispersant, sodium poly (meth) acrylate, ammonium poly (meth) acrylate, sodium acrylate / sodium maleate copolymer, ammonium acrylate / ammonium maleate copolymer; as an alkali acting agent, Sodium hydroxide, hydroxylamine; sodium carbonate, sodium silicate as those that react with polyvalent cations to form insoluble salts or complex salts; other organic lytic agents such as polyethylene glycol, polypropylene glycol, sodium fumate, and lignin. Examples thereof include sodium sulfonate.

Preferable examples include phosphate-based dispersants, polycarboxylic acid-based dispersants, and other organic defibrators. Here, the polycarboxylic acid salt-based dispersant is more preferably one having a weight average molecular weight of 1,000 to 20,000.

Specifically, sodium pyrophosphate as a phosphate-based dispersant, sodium polyacrylate or ammonium polyacrylate having a weight average molecular weight of 1,000 to 20,000 as a polycarboxylic acid salt-based dispersant, and weight of other organic lytic agents. Polyethylene glycol (PEG900 or the like) having an average molecular weight of 200 to 20,000 is preferable.

Low-polymerized sodium polyacrylate having a weight average molecular weight of 1,000 to 20,000 interacts with silicate particles to generate a negative charge derived from carbonic anion on the particle surface, and disperses the silicate by repulsion of the charge. It is known to act as a dispersant by mechanism.

The content of the dispersant (C1) is 0.001% by mass to 20% by mass, preferably 0.01% by mass to 10% by mass in 100% by mass of hydrogel.
In the preparation of a hydrogel containing a water-soluble organic polymer (A1), a silicate (B1) and a dispersant (C1) of the silicate having an organic acid salt structure or an organic acid anion structure, the above component (B1) ), When a silicate containing a dispersant is used, the dispersant as the component (C1) may or may not be further added.

Further, in the above hydrogel, monohydric or polyhydric alcohols such as methanol, ethanol and glycol, formamide, hydrazine, dimethyl sulfoxide, urea and acetamide are used to intercalate between the layers of the layered silicate and promote the peeling. , And potassium acetate and the like can be added.

As a hydrogel containing a water-soluble organic polymer (A1) having an organic acid salt structure or an organic acid anion structure, a silicate (B1) and a dispersant (C1) of the silicate, a silicate (clay mineral) is used. It is preferably formed from a composition containing, an aqueous dispersant, and a polyacrylate.

Further, as a preferable combination of the water-soluble organic polymer (A1), the silicate (B1), and the dispersant (C1) of the silicate, the weight average molecular weight as the component (A1) in 100% by mass of the hydrogel is used. 2 to 7 million completely or partially neutralized non-crosslinked sodium polyacrylate 0.1% by mass to 10% by mass, water-swellable smectite or saponite 0.1% by mass as component (B1) To 15% by mass, and 0.01% by mass to 10% by mass of sodium pyrophosphate as a component (C1), 0.01% to 10% by mass of polyacrylate having a weight average molecular weight of 1000 to 20,000, or a weight average molecular weight. 200 to 20,000 polyethylene glycols are 0.01% by mass to 10% by mass.

In the radiation dosimetry gel of the present invention, a preferable combination of the water-soluble polymer (A) and the hydrogel (B) to be colored by the radiation decomposition product is colored by the radiation decomposition product in 100% by mass of the radiation dosimetry gel. 0.1% by mass to 3.0% by mass, preferably 0.2% by mass to 2.0% by mass of the water-soluble polymer (A), and gelatin as the component (B) in 100% by mass of the radiation dosimetry gel. Examples include combinations of 0.1% by mass to 10% by mass.
The concentration of the substituent colored by the radiolysis product present in the water-soluble polymer (A) colored by the radiolysis product is preferably 0.1 mM to 5.0 mM in the gel. If the concentration of the substituent is lower than 0.1 mM, the sensitivity to radiation may be insufficient.

Further, in the radiation dose measurement gel of the present invention, a water-soluble polymer (A), a silicate dispersant (B), a water-soluble organic polymer (A1) and a silicate (B1), which are colored by a radiation decomposition product, are used. ) And the silicate dispersant (C1) are preferably 0.1% by mass to 1.0% by mass of the water-soluble polymer (A) colored by the radiation decomposition product in 100% by mass of the radiation dose measurement gel. %, preferably 0.1% by mass to 0.5% by mass, in 100% by mass of the radiation dose measurement gel, as a component (A1), a weight average molecular weight of 2.5 million or more and 5 million or less is directly neutralized or partially neutralized. Chain type sodium polyacrylate 0.03% by mass to 10% by mass, water-swellable smectite or saponite 0.1% by mass to 10% by mass as component (B1), and 0.01% by mass of sodium pyrophosphate as component (C1) % To 10% by mass, or a combination of 0.01% by mass to 10% by mass of low-polymerized sodium polyacrylate having a weight average molecular weight of 1000 or more and 20,000 or less.

The hydrogel (B) may be one kind or a combination of two or more kinds, but it is preferably composed of one kind.

The concentration of the substituent colored by the radiolysis product present in the water-soluble polymer (A) colored by the radiolysis product is preferably 0.1 mM to 0.5 mM in the gel. If the concentration of the substituent is lower than 0.1 mM, the sensitivity to radiation may be insufficient.

In addition, the radiation dosimetry gel of the present invention may contain an organic halogen compound in order to improve the sensitivity to radiation.
As the organic halogen compound, in principle, any conventionally known compound can be used, and the organic halogen compound is not particularly limited, but in particular, an organic halogen compound having a structure that easily releases halogen radicals by irradiation with radiation is used. It is preferable to use it.

Examples of such compounds include carbon tetrachloride, tetrabromomethane, chloroform, bromoform, dichloromethane, dibromomethane, 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, 1,2, 3-Trichloropropane, 1,2,3-tribromopropane, 1,1,1-trichloroethane, 1,3-dibromobutane, 1,4-dibromobutane, 1,2-dichloroethane, n-octyl chloride, isopropyl bromide , Parklen, Triclin, 1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, 1,2,4-trichlorobenzene, o-dichlorobenzene, o-dibromobenzene, p-dichlorobenzene , P-dibromobenzene, monochlorobenzene, monobromobenzene, monoiodobenzene, trichloroacetic acid, tribromoacetic acid, ethyl α-bromoisobutyrate, phenyltrifluoromethane, 1,1,3-trihydrotetrafluoropropanol, 4,4'- Dichlorodiphenyl-2,2-propane, o-chloroaniline, p-chloroacetophenone, o-chlorobenzoic acid, 3,4-dichlorotoluene, o-chloronitrobenzene, p-chlorobenzotrichloride, benzotrifluoride, 3, 3'-dichloro-4,4'-diaminodiphenylmethane, N-bromosuccinimide, α, α, α-tribromomethylphenyl sulfone, 2', 2'-bis (2-chlorophenyl) -4,4', 5, Examples thereof include, but are not limited to, 5'-tetraphenyl-1,1'-bi-1H-imidazole, and water-holding chloroform. Preferred are trichloroacetic acid or tribromoacetic acid.

The amount of the organic halide compounded can be in the range of 0.1 part by mass to 1.0 part by mass when the entire radiation dosimetry gel is 100 parts by mass.
Since the organic halogen compound can be decomposed by irradiation with radiation to generate a halogen radical, the sensitivity of the radiation dosimetry gel can be improved.

In addition, the radiation dosimetry gel of the present invention may contain a known pH adjuster as long as the effects of the present invention are not impaired. Examples of the pH adjusting agent include pH adjusting agents such as glucono-δ-lactone, perchloric acid, sulfuric acid and salt.
In addition, the radiation dosimetry gel of the present invention may contain a known polymerization inhibitor, ultraviolet absorber, or the like in order to suppress polymerization by residual monomers after irradiation.

[Manufacturing method of radiation dosimetry gel]
The method for producing the radiation dose measurement gel of the present invention is not particularly limited, but a method of gelling by mixing the component (A) and the component (B), or the component (A), the component (A1), and the like. Gelation by mixing a mixture of at least two components of the component (B1) and the component (C1) or an aqueous solution or an aqueous solution thereof and a mixture of the remaining components or the remaining components or an aqueous solution or an aqueous solution thereof. There is a method of making it.
If necessary, the component (A) can be reacted with an acid such as trichloroacetic acid to form a salt form, which can be mixed with other components.

As a method of mixing each component, ultrasonic treatment can be used in addition to mechanical or manual stirring, but mechanical stirring is particularly preferable. For mechanical stirring, for example, a magnetic stirrer, a propeller type stirrer, a rotation / revolution type mixer, a disper, a homogenizer, a shaker, a vortex mixer, a ball mill, a kneader, an ultrasonic oscillator and the like can be used. Among them, the mixing is preferably performed by a rotating / revolving mixer.

The temperature at the time of mixing is the freezing point to the boiling point of the aqueous solution or the aqueous dispersion, preferably −5 ° C. to 50 ° C.

Immediately after mixing, the strength is weak and it is sol-like, but it gels when left to stand. The standing time is preferably 2 hours to 100 hours. The standing temperature is −5 ° C. to 100 ° C., preferably 0 ° C. to 30 ° C. In addition, a radiation dosimetry gel having an arbitrary shape can be produced by pouring it into a mold or extruding it immediately after mixing before gelling.
In addition, it can be used as a sol as long as the radiation dosimetry ability is not lost.

<Radiation dosimeter>
Since the radiation dosimetry gel of the present invention is suitable as a radiation dose measurement material, the radiation dosimetry gel can be filled in a container to form a radiation dosimeter, for example, a phantom. The container is not particularly limited as long as it transmits radiation and has solvent resistance, airtightness, and the like, and the material thereof is preferably glass, acrylic resin, polyester, ethylene-vinyl alcohol copolymer, or the like. Further, after filling the container, it may be replaced with nitrogen gas or the like.

Next, the contents of the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

In the examples, the equipment and conditions used for sample analysis are as follows.
(1) ^{1 1} H-NMR
The compound was dissolved in deuterated chloroform (CDCl ₃ ), and ¹ H-NMR was measured using a nuclear magnetic resonance apparatus (300 MHz, manufactured by Diol).
(2) Measurement of average molecular weight Using a GPC apparatus (manufactured by Shimadzu Corporation, columns: KF804L and KF803L, solvent: tetrahydrofuran, temperature: 40 ° C., flow rate: 1 ml, calibration curve: standard polystyrene), the number average molecular weight (Mn) ), The weight average molecular weight (Mw) was measured.
(3) X-ray irradiation device: Industrial X-ray device (Radioflex 250CG, Rigaku)
Irradiation conditions: 250 kVp, 4 mA, 1 mm aluminum filter, dose rate 1.0 Gy / min. A sample was placed on the circumference of 18 cmΦ and irradiated.
(4) Light absorption spectrum measuring device: Agilent 8453 UV-Visible Spectroscopy
System (manufactured by Agilent Technologies, Inc.)
(5) Diffusion evaluation / comparative experiment Equipment: UV-3600 UV-VIS-NIR Spectrophotometer (manufactured by Shimadzu Corporation)

Synthesis example 1
Synthesis of compound (3)

It was synthesized according to the method described in International Publication No. 2016/002842 Pamphlet.
Methyl isobutyl ketone (MIBK) 60 ml, 4-formylbenzoic acid 5.0 g (33 mmol), N, N-diethylaniline 16.1 g (133 mmol) and p-toluene in a 200 ml eggplant flask with a Dean-Stark tube and a cooling tube. 6.3 g (33 mmol) of sulfonic acid / monohydrate (p-TSA) was added to prepare a mixture, and the mixture was reacted at a temperature of 129 ° C. for 20 hours with stirring. After completion of the reaction, 150 ml of dichloromethane was added, the mixture was washed twice with pure water, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a green liquid.
This liquid was purified by silica column chromatography (column: silica gel 60 0.063-0.200 mm manufactured by Merck, eluate: hexane / ethyl acetate = 1/1). The solvent of the solution obtained here was distilled off to obtain 8.9 g (yield 63%) of the target compound (3).
^{1 1} H NMR (CDCl ₃ ) δ: 1.15 (t, 12H), 3.33 (q, 8H), 5.38 (s, 1H), 6.60 (m, 4H), 6.95 (m, 4H), 7.25 (m, 2H) , 7.98 (m, 2H).

Synthesis of compound (4)

It was synthesized according to the method described in International Publication No. 2016/002842 Pamphlet.
Compound (3) 1.6 g (3.7 mmol), 2-hydroxyethyl methacrylate (HEMA) 0.49 g (3.7 mmol), and N, N-dimethyl-4-aminopyridine (DMAP) 0.14 g at room temperature. After stirring, the mixture was suspended in 16 ml of methylene chloride, and 0.78 g (4.1 mmol) of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) was added to the solution for 48 hours. Stirred. After the reaction, the mixture was washed twice with 150 ml of pure water, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a yellow liquid. This liquid was purified by silica column chromatography (column: silica gel 60 0.063-0.200 mm manufactured by Merck, eluate: hexane / ethyl acetate = 1/1). The solvent of the solution obtained here was distilled off to obtain 1.9 g (yield 95%) of the target polymerizable compound (4).
^{1 1} H NMR (CDCl ₃ ) δ: 1.13 (t, 12H), 1.95 (s, 3H), 3.32 (q, 8H), 4.46 (m, 2H), 4.54 (m, 2H), 5.37 (s, 1H) , 5.59 (m, 1H), 6.14 (m, 1H), 6.60 (m, 4H), 6.95 (m, 4H), 7.25 (m, 2H), 7.94 (m, 2H).

Synthesis of polymer (1)

0.7 g (1.3 mmol) of the polymerizable compound (4) obtained in Synthesis Example 1, 4.5 g (4.7 mmol) of poly (ethylene glycol) methyl ether methacrylate (Mn950), in a flask provided with a cooling tube. 12 g of N-methyl-2-pyrrolidone (NMP) and 0.01 mg of azobisisobutyronitrile (AIBN) were charged, the inside of the flask was replaced with nitrogen, and the mixture was stirred at 75 ° C. for 20 hours for reaction. The obtained reaction solution was poured into 300 mL of hexane to precipitate a white powder. This powder was dissolved in tetrahydrofuran (THF) and reprecipitated by adding it to hexane, and then the powder obtained by decantation was vacuum dried to 3.7 g (yield 71%) of the polymer (1). Got
The Mn of the obtained polymer (1) was 31857 and the Mw was 48080 (Mw / Mn = 1.5).

[Example 1: Manufacture of a radiation dosimeter (dye gel dosimeter) provided with a radiation dose measurement gel as a radiation dose measurement material]
0.06 g of the polymer (1) obtained in Synthesis Example 1 was added to 10.0 g of water, and after stirring at room temperature for 10 minutes, 0.06 g of trichloroacetic acid (TCAA, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and at room temperature. The mixture was stirred for 2 minutes.
On the other hand, 1.2 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich) was added to 18.7 g of water, and the mixture was stirred at 45 ° C. A solution of the polymer (1) / TCAA was added to the obtained gelatin solution at 30 ° C., and the mixture was stirred. The obtained mixture was filled in a 1 × 1 × 4.5 cm cuvette and allowed to stand in a cool and dark place for 12 hours to obtain a radiation dosimeter for an irradiation test.

[Example 2: Manufacture of a radiation dosimeter (dye gel dosimeter) provided with a radiation dose measurement gel as a radiation dose measurement material]
0.12 g of the polymer (1) obtained in Synthesis Example 1 was added to 10.0 g of water, stirred at room temperature for 10 minutes, then 0.06 g of trichloroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was added at room temperature for 2 minutes. Stirred.
On the other hand, 1.2 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich) was added to 18.6 g of water, and the mixture was stirred at 45 ° C. A solution of the polymer (1) / TCAA was added to the obtained gelatin solution at 30 ° C., and the mixture was stirred. The obtained mixture was filled in a 1 × 1 × 4.5 cm cuvette and allowed to stand in a cool and dark place for 12 hours to obtain a radiation dosimeter for an irradiation test.

[Example 3: Manufacture of a radiation dosimeter (dye gel dosimeter) provided with a radiation dose measurement gel as a radiation dose measurement material]
0.06 g of the polymer (1) obtained in Synthesis Example 1 was added to 10.0 g of water, stirred at room temperature for 10 minutes, then 0.12 g of trichloroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was added at room temperature for 2 minutes. Stirred.
On the other hand, 1.2 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich) was added to 18.7 g of water, and the mixture was stirred at 45 ° C. A solution of polymer (1) / TCAA was added to the obtained gelatin solution at 30 ° C., and the mixture was stirred. The obtained mixture was filled in a 1 × 1 × 4.5 cm cuvette and allowed to stand in a cool and dark place for 12 hours to obtain a radiation dosimeter for an irradiation test.

[Example 4: Manufacture of a radiation dosimeter (dye gel dosimeter) provided with a radiation dose measurement gel as a radiation dose measurement material]
0.12 g of the polymer (1) obtained in Synthesis Example 1 was added to 10.0 g of water, stirred at room temperature for 10 minutes, then 0.12 g of trichloroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was added at room temperature for 2 minutes. Stirred.
On the other hand, 1.2 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich) was added to 18.6 g of water, and the mixture was stirred at 45 ° C. A solution of the polymer (1) / TCAA was added to the obtained gelatin solution at 30 ° C., and the mixture was stirred. The obtained mixture was filled in a 1 × 1 × 4.5 cm cuvette and allowed to stand in a cool and dark place for 12 hours to obtain a radiation dosimeter for an irradiation test.

[Example 5: Irradiation test of manufactured radiation dosimeter (dye gel dosimeter)]
Radiation dosimeter for irradiation test manufactured in Example 1 with X-rays (250 kV, 4 mA) at 1 Gy / min using Radioflex 250 CG (Rikagaku Denki Co., Ltd.) at 3, 5, 10, 20, 30, and 40 Gy. Was irradiated and coloring (light green) was confirmed using the light absorption spectrum. It was observed that the green coloration gradually became darker as the irradiation amount increased.
Similarly, the radiation dosimetry gels of Examples 1 to 4 were irradiated with 0 to 40 Gy of x-ray radiation, and the absorbance spectrum of the irradiated radiation dosimetry gels was measured.
The results of the absorption spectrum measurement of the radiation dosimetry gels of Examples 1 to 4 irradiated with x-ray radiation (30 Gy) are shown in FIG. From FIG. 1, the radiation dosimetry gels of Examples 3 and 4 in which the amount of trichloroacetic acid added is large are larger than those of the radiation dosimetry gels of Examples 1 and 2 in which the amount of trichloroacetic acid added is small. It was confirmed that the sensitivity of the above was improved.
Further, FIG. 2 shows the result of irradiation dose dependence (increase in absorbance with respect to irradiation dose) for the absorbance at the maximum wavelength (about 650 nm) of the absorbance spectrum. From FIG. 2, it was clarified that the amount of increase in absorbance with respect to the irradiation dose showed linear dose responsiveness. Therefore, it was confirmed that the radiation dosimetry gel of the present invention can be used in an apparatus capable of measuring absorbance and can be used as a radiation dosimeter.

[Example 6: Diffusion evaluation test of reacted radiation dosimetry gel]
0.12 g of the polymer (1) obtained in Synthesis Example 1 was added to 10.0 g of water, stirred at room temperature for 10 minutes, then 0.12 g of trichloroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was added at room temperature for 2 minutes. Stirred.
On the other hand, 1.2 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich) was added to 18.6 g of water, and the mixture was stirred at 45 ° C. A solution of the polymer (1) / TCAA was added to the obtained gelatin solution at 30 ° C., and the mixture was stirred. A diffusion evaluation test of a radiation dosimetry gel was performed using the obtained mixture.
Trichloroacetic acid-containing gelatin samples obtained from 0.12 g of trichloroacetic acid, 1.20 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich), and 28.7 g of water up to 2.5 cm in a 1 x 1 x 4.5 cm cuvette. Filled. The upper part of the cuvette was filled with 1.0 g of the radiation dosimetry gel of Example 4 irradiated with ultraviolet rays using Handy UV Lamp SLUV-4 (365 nm, manufactured by AS ONE) in the gel state. By measuring the absorption spectrum (400 to 800 nm) of this cuvette trichloroacetic acid-containing gelatin sample, the dye diffused from the radiation dosimeter gel into gelatin was evaluated (see FIG. 3).
On the other hand, as a reference sample for diffusion comparison between Examples and Comparative Examples, a 1 × 1 × 4.5 cm cuvette was filled with a gelatin sample containing trichloroacetic acid up to 2.5 cm, and Handy UV Lamp SLUV-4 was placed on top of the sample. 1.0 g of the radiation dosimetry gel of Example 4 irradiated with ultraviolet rays was filled in the gel state, and the gel was heated and melted to prepare a homogenized product (see FIG. 4).
The diffusion rate of each radiation dosimetry gel into a trichloroacetic acid-containing gelatin sample was evaluated using the absorbency of the reference sample as a reference (100%).

[Comparative Example 1: Diffusion evaluation test of reacted micelle dosimeter gel]
0.014 g of Leuco Crystal Violet (LCV) is added to 10.0 g of water, and after stirring at room temperature for 10 minutes, 0.15 g of trichloroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and polyethylene glycol mono-4-octylphenyl ether (Tokyo). 0.26 g (manufactured by Kasei Kogyo Co., Ltd.) was added and stirred at room temperature for 2 minutes to obtain a solution of LCV / TCAA / polyethylene glycol mono-4-octylphenyl ether.
On the other hand, 1.50 g of gelatin (Gelatin from porcine skin, Sigma-Aldrich) was added to 15.44 g of water, and the mixture was stirred at 45 ° C. A solution of LCV / TCAA / polyethylene glycol mono-4-octylphenyl ether was added to the obtained gelatin solution at 30 ° C., and the mixture was stirred. The obtained mixture was filled in a glass vial for 50 ml and allowed to stand in a cool and dark place for 12 hours to obtain a radiation dosimetry gel for a diffusion evaluation test.
This radiation dosimetry gel was subjected to a diffusion evaluation experiment by the same method as in [Example 6].

For the radiation dosimetry gels of Example 6 and Comparative Example 1, the trichloroacetic acid-containing gelatin sample portion 0 day (the day), 1 day, 2 days, 3 days, 6 days, 8 days, 10 days, and 14 days after the sample preparation. The maximum absorption wavelength (Example 6: about 650 nm, Comparative Example 1: about 600 nm) was read, and the change over time in the relative increase in absorbance with respect to the absorbance (100%) of the reference sample was plotted. The graph is shown in FIG.
From FIG. 5, both Example 6 and Comparative Example 1 were observed to have a linear relative increase in absorbance, but radiation dosimetry containing the water-soluble polymer (A) colored by the radiolysis product of the present invention. It was confirmed that the gel had a lower diffusion rate than the gel containing the leuco compound (leuco crystal violet).
Therefore, it was confirmed that the radiation dosimeter gel of the present invention can be used as a measurement material for the radiation dosimeter.

Claims (8)

1. A radiation dosimetry gel containing a water-soluble polymer (A) and a hydrogel (B) that are colored by a radiolysis product.
2. The radiation dosimeter gel according to claim 1, further containing the organic halogen compound (C).
3. The radiation dosimetry gel according to claim 1 or 2, wherein the water-soluble polymer (A) contains a group derived from a leuco compound.
4. The water-soluble polymer (A) has the following formula (A-1):
   

   

   
   (In the above formula (A-1),
   Ar is
   

   

   
   Represents
   A ₁ represents a single bond, -COO-, -OCO-, -NR _1- or -O-
   p is 0 when A ₁ represents a single bond, and is an integer of 1 to 12 when A ₁ represents -COO-, -OCO-, -NR _1- or -O-.
   R ₁ is independently a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, a sulfoalkyl group having 1 to 6 carbon atoms, and 2 to 7 carbon atoms. Carboxyalkyl group, cyanoalkyl group having 2 to 7 carbon atoms, alkoxyalkyl group having 2 to 6 carbon atoms, halogenoalkyl group having 1 to 6 carbon atoms, phenyl group having or unsubstituted substituent, or or represents a or unsubstituted benzyl group substituents, or R ₁ together may have to form a 3 to 10-membered ring together with the nitrogen atom attached, X ₁ and X ₂ are, each independently,
   

   

   
   (In the above formula, R ₁ has the same meaning as above, and R ₂ independently represents a hydrogen atom, a methyl group or a phenyl group).
   X ₃ represents a water-soluble group
   Q represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a heteroatom, and when the total number of repeating units constituting the water-soluble polymer (A) is 1, the water-soluble polymer (Q) The ratios n and m of the repeating units in the formula (A-1) constituting A) are numbers that satisfy 0 <n ≦ 0.5, 0 <m ≦ 1, and m + n ≦ 1. )
   The radiation dosimetry gel according to any one of claims 1 to 3, which is represented by.
5. The water-soluble polymer (A) has the following formula (A-2):
   

   

   
   (In the above formula (A-2),
   Ar is
   

   

   
   Represents
   A ₁ represents a single bond, -COO-, -OCO-, -NR _1- or -O-.
   A ₂₁ represents -O- or -NR _1-
   p is 0 when A ₁ represents a single bond, and represents an integer from 1 to 12 when A ₁ represents -COO-, -OCO- or -O-.
   r represents an integer of 1 or 2
   q represents an integer from 1 to 50
   R ₁ represents an alkyl group having 1 to 6 carbon atoms.
   R ₂ and R ₃ independently represent a hydrogen atom or a methyl group, respectively.
   R ₄ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
   Q represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a heteroatom.
   When the total number of repeating units constituting the water-soluble polymer (A) is 1, the proportions n and m of the repeating units in the formula (A-1) constituting the water-soluble polymer (A) are 0 <. It is a number that satisfies n ≦ 0.5, 0 <m ≦ 1, and m + n ≦ 1. )
   The radiation dosimetry gel according to any one of claims 1 to 4, which is represented by.
6. The radiation dosimetry gel according to any one of claims 1 to 5, wherein the hydrogel (B) is selected from gelatin, agarose or gellan gum.
7. Claim 1 in which the hydrogel (B) comprises a water-soluble organic polymer (A1) having an organic acid salt structure or an organic acid anion structure, a silicate (B1), and a dispersant (C1) of the silicate. The radiation dosimetry gel according to any one of claims 6.
8. A radiation dosimeter provided with the radiation dosimetry gel according to any one of claims 1 to 7 as a radiation dose measurement material.

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