JP2009265034A - Color dosimeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color dosimeter capable of detecting a radiation dose easily by color development generated by irradiation, and selecting a hue change to be detected. <P>SOLUTION: This color dosimeter for detecting a radiation by color development caused by a chemical reaction includes at least an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative. In the color dosimeter for detecting a radiation by color development generated by irradiating the derivatives with radiation, the radiation can be detected at high sensitivity and with superior reproducibility by the irradiation of the radiation of about several Gy, and observation will not be prevented, even in X-ray fluoroscopy, such as IVR. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color dosimeter.

  The radiation referred to in the present invention refers to beta rays (electron beams) that are charged particles, and gamma rays and X-rays that are electromagnetic waves, and these radiations are widely used in the medical field. Specifically, a diagnostic technique such as X-ray photography as well as a peripheral region such as a sterilization treatment of a medical instrument or a medical instrument can be given. Recently, it has come to be actively used as an indirect or direct treatment method for the human body, such as irradiation of blood for transfusion or cancer treatment. It is said that this trend will become even higher in the future.

  One reason is the reduction of physical burden on the patient. In the past, for diseases that could only be dealt with by surgery or for diseases that were difficult to perform, surgery could be taken or only symptomatic treatment was possible. However, it should be handled in a way that greatly reduces the load on the human body, such as computed tomography (CT) using X-rays and catheter surgery using continuous X-ray imaging (interventional radiology, hereinafter IVR). Became possible.

  However, since radiation exposure to patients is accompanied, some patients have radiation skin damage due to excessive irradiation (for example, Non-Patent Document 1). Based on this situation, there is an urgent need to create an environment that will not cause skin damage to medical practices that use radiation, and to be able to take appropriate measures in the event of a failure.

  The following methods are used in the conventionally used radiation measurement methods. Examples include ionization chambers, proportional counters, GM counters, scintillation counters, semiconductor detectors, thermofluorescence dosimeters, fluorescent glass dosimeters, photographic films, and color dosimeters. These measurement methods require special devices, and it is difficult to specify the irradiation range depending on the situation, and it is difficult to use in a medical field where the irradiation dose varies.

  Recently, color dosimeters have attracted attention. A color dosimeter visually indicates the presence of energy, such as beta rays (electron rays), gamma rays, and X-rays, that cannot be captured by the human eye, using a simple method using chemical or physical reactions. The amount of irradiation is detected.

  A typical color dosimeter uses one of the following three reactions. That is, (1) radiolysis reaction of organic halide, (2) radiation polymerization reaction, and (3) photochromic reaction utilizing scintillation. Each will be described in detail below.

(1) Radiolysis reaction of organic halide This reaction uses acid-generated hydrogen halide generated by radiolysis of an organic halide. Irradiation generates hydrogen halide and increases the hydrogen ion concentration in the dosimeter. At this time, a color change reaction occurs by combining a pH indicator. The irradiation dose is quantified using this discoloration state.

One specific material used is a combination of a leuco dye and polyvinyl chloride (for example, Patent Document 1).
This method changes color when the radiation dose is 5,000 to 25,000 Gy or more. In addition, since the acid generated is volatile, good reproducibility may not be obtained.

(2) Radiation polymerization reaction This reaction utilizes radiation polymerization of a diacetylene compound having two alkynyl groups in one molecule (for example, Patent Document 2). This type of compound crystallizes so that alkynyl groups are spontaneously stacked just by applying a solution. Therefore, if an external stimulus such as X-ray is given in the solid phase, a chain polymerization reaction occurs. As a result, a compound in which π electron conjugation is developed is generated. Visibility is developed because the product has absorption in the visible light region.

  Although this technique shows sensitivity even in a relatively low dose region of about 100 Gy, since it takes 1 hour or more to complete the reaction, it is inferior in immediacy and has a problem of quantitative evaluation.

(3) Photochromic reaction using scintillation This reaction uses a diarylethene compound exhibiting photochromic characteristics as a detection material (for example, Patent Document 3).

  In general, photochromic materials do not exhibit chromic properties in radiation chemical reactions. Therefore, the radiation energy is converted into light energy that causes photochromism by a scintillator, and a photochromic reaction by the light energy is used.

  Since an inorganic scintillator is necessary for increasing the sensitivity of this method, there is a problem of image quality degradation when using an X-ray fluoroscopic image such as IVR. Further, since this reaction is reverse reaction by light, it is necessary to strictly manage the storage state after the reaction, and the sensitivity is exhibited even for a low dose of about several Gy.

  The conventional methods roughly classified into the above three types are dosimeters that use the reaction of a single chemical species by radiation action. In contrast, the present invention is a completely new method for forming a chromophore by a radiation chemical reaction between two kinds of molecules, an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative.

  In the reaction mechanism of the present invention, the tetrahalogenated methane or trihalogenated methane derivative is decomposed by irradiation, and active species generated in the process are coupled with the arylamine derivative to form a chromophore only. Here, the chromophore is rapidly generated, and the amount of generation is not dependent on the energy intensity of radiation, but is dependent on the irradiation amount. That is, unlike the photochromic reaction, it does not depend on the wavelength at all.

  In addition, there is a report example about the photochromic reaction (photochemical reaction) by the ultraviolet irradiation to the reaction system implemented by the structure similar to this invention (for example, nonpatent literature 2). In the reaction mechanism of Non-Patent Document 2, the tetrahalogenated methane or trihalogenated methane derivative is activated from the ground state HOMO to the excited state LUMO by ultraviolet irradiation and is coupled with the arylamine derivative to form a chromophore. Is. In order to generate the active species generated here, ultraviolet irradiation with a specific wavelength corresponding to the excitation of the tetrahalogenated methane or trihalogenated methane derivative from the ground state HOMO to the excited state LUMO is indispensable. Irradiation is characterized in that no chromophore formation occurs. This point is common to all photochromic chemical reactions and is essentially different from the radiation chemical reaction used in the present invention.

As described above, the reaction mechanism of the present invention is greatly different from the reaction mechanism in the photochromic reaction, but it is presumed that the chromophore finally produced is the same as that of the present invention.
However, there are few known cases in which the reaction caused by irradiation with radiation is caused by the photochromic reaction in the same configuration as in the present invention.

  An example of a typical reaction product shown in Non-Patent Document 2 is shown below.

The above reaction product is one of the products in the case where the tetrahalogenated methane in the present invention is carbon tetrabromide and the arylamine derivative is diphenylamine.
Japanese Patent Publication No. 06-072929 JP 2000-241548 A JP 2005-082507 A N. Nakamura, Kunihiko Morosumi, Atsuhiko Togashi, “Clinical IVR and Exposure Protection”, Medical Science, Inc., Tokyo (2004) R. H. SPRANGUE et al. , PHOTOGRAPHIC Science and Engineering 1961, 5 (2), 98-103.

As described above, conventionally, there has been no color dosimeter that can detect irradiation with a low radiation dose of about several Gy, is excellent in immediacy, and does not interfere with observation even in X-ray fluoroscopy like IVR.
The present invention has been made in view of such a background art, and provides a color dosimeter capable of easily detecting a radiation dose by color development by irradiation of radiation and selecting a detected hue change. It is in.

  As a result of intensive studies to solve the above problems, the present inventors found at least a color dosimeter that forms a chromophore by a radiation chemical reaction between two or more different types of molecules, and completed the present invention. It came.

  That is, a color dosimeter that solves the above-mentioned problem is a color dosimeter that detects radiation by color development by a chemical reaction, and contains at least an arylamine derivative and a tetrahalogenated methane or a trihalogenated methane derivative, Radiation is detected by color development generated by irradiating the derivative with radiation.

The present invention can provide a color dosimeter that can detect radiation with high sensitivity and with high reproducibility by radiation irradiation of several Gy, and that does not hinder observation even in X-ray fluoroscopy such as IVR.
In addition, the present invention uses a reaction that occurs only at the time of irradiation, and thus has immediacy and no discoloration due to a change with time. In addition, the hue of color can be changed by introducing different substituents into the arylamine derivative.

Hereinafter, the present invention will be described in detail.
A color dosimeter according to the present invention is a color dosimeter for detecting radiation by color development by a chemical reaction, and contains at least an arylamine derivative and a tetrahalogenated methane or a trihalogenated methane derivative, and the derivative is irradiated with radiation. It is characterized in that radiation is detected by color development generated by irradiation.

  It is preferable that the arylamine derivative is composed of a compound represented by the following general formula (1).

(In the formula, Ar represents an aryl group. R 1 and R 2 represent a hydrogen atom, an alkyl group, or an aryl group.)

  The trihalogenated methane derivative is preferably composed of a compound represented by the following general formula (2).

(In the formula, X represents one or more halogen atoms selected from a chlorine atom, a bromine atom and an iodine atom. R represents a hydrogen atom, an alkyl group or an aryl group.)
In the compound represented by the general formula (2) of the trihalogenated methane derivative, R may be any of a hydrogen atom, an alkyl group, and an aryl group.

  In addition, R1 and R2 of the compound represented by the general formula (1) are each independently a hydrogen atom; a C1-C10 alkyl group such as a methyl group, an ethyl group, or a propyl group; a phenyl group, a naphthyl group, a pyridyl group, An aryl group such as a phenoxy group is exemplified. An aryl group such as a phenyl group, a naphthyl group, or a pyridyl group may have a substituent.

  The arylamine derivative may have a cyclic structure such as carbazole.

In the compound represented by the general formula (2) of the trihalogenated methane derivative, Ar includes an aryl group such as a phenyl group, a naphthyl group, and a pyridyl group which may have a substituent. Examples of the substituent include C1-C10 alkyl groups such as methyl, ethyl, and propyl; C1-C10 alkoxy groups such as methoxy, ethoxy, and propoxy; C1-C10 such as methylthio, ethylthio, and propylthio. C10 alkylthio group; phenyl group; phenoxy group; hydroxyl group; nitro group; halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom. The position of the substituent is not particularly limited as long as the performance is not impaired. In the case of having a plurality of the substituents, the substituents are not necessarily the same.
There are many commercially available arylamine derivatives, tetrahalogenated methanes, and trihalogenated methane derivatives, and they are easily available.

  In the color dosimeter of the present invention, the arylamine derivative and the tetrahalogenated methane or trihalogenated methane derivative can be used as a solution, or dissolved and dispersed in a resin and used as a film. It is also possible to do. It is also possible to manipulate the hue of color by manipulating the substituent of the arylamine.

  Regarding the mode of the color dosimeter, a solution in which an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative are dissolved may be used, or the solution may be applied to prepare a film. Alternatively, it may be dissolved in a resin solution to form a paint, which may be used in the form of a sheet.

  The color dosimeter configured as described above can be used by a method according to the mode. Each aspect is demonstrated below about the utilization method as a color dosimeter.

Liquid Composition The color dosimeter of the present invention can be prepared by dissolving an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative in a common solvent.

  The solvent should be a liquid that dissolves the arylamine derivative and the tetrahalogenated methane or trihalogenated methane derivative, and does not interfere with the detection of the discolored state by irradiation when used as a color dosimeter. If it does not specifically limit. Specific examples include aromatic solvents such as benzene and toluene, halogen solvents such as chloroform, and various organic solvents such as hexane and cyclohexanone.

The addition amount of the arylamine derivative and the addition amount of the tetrahalogenated methane or trihalogenated methane derivative is preferably independently in the range of 10 ⁻⁵ to 10 ¹ mol / dm ³ with respect to the aforementioned solvent, It is not necessary to add equimolar amounts.
In addition, you may use well-known antioxidant, an oxygen trap agent, a plasticizer, a ultraviolet absorber, etc. together.

If a mixed solution of the arylamine derivative and tetrahalogenated methane or trihalogenated methane derivative prepared as described above is sealed in a cell containing no impurities, a color dosimeter is obtained.
By irradiating the created cell with radiation, the color tone of the solution changes according to the radiation dose. Although it is possible to visually recognize the irradiation dose by comparison with a color sample, it is possible to measure the radiation dose in more detail by measuring the amount of change in the absorption / transmission spectrum or reflection spectrum.

Resin Composition A color dosimeter composed of an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative in the present invention is, for example, dispersed in a solvent together with the base resin, or directly on the base resin. It can be prepared by dissolving.

  The base resin is not particularly limited as long as it can satisfactorily dissolve the arylamine derivative and the tetrahalogenated methane or trihalogenated methane derivative. Specifically, cellulose resin, acrylic resin, methacrylic acid resin, vinyl acetate resin, vinyl chloride resin, polyethylene resin, polypropylene resin, polystyrene resin, polynaphthalene resin, polycarbonate resin, polyethylene terephthalate resin, polybilyl butyral resin, Or the mixture of the said resin, resin copolymerized, etc. are mentioned.

  When the arylamine derivative and the tetrahalogenated methane or trihalogenated methane derivative and the base resin are dispersed in a solvent in the resin, the arylamine derivative and the tetrahalogenated methane or trihalogenated methane derivative are preferable as the solvent. Any material can be used as long as it does not interfere with the molding process. Specific examples include various organic solvents such as aromatic solvents such as benzene and toluene, organic halide solvents such as chloroform, and aliphatic solvents such as hexane and THF.

  The concentration of the arylamine derivative and the tetrahalogenated methane or trihalogenated methane derivative contained in the resin solution can be set independently, but 0.2 to 200 with respect to 100 parts by weight of the base resin. A range of parts by weight is preferred. In addition, you may add well-known antioxidant, an oxygen trap agent, a plasticizer, etc.

In the case of a method of directly dissolving in a base resin, a resin composition is prepared by directly kneading an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative into the base resin.
The resin composition prepared by the above method can be used as a color dosimeter if it is molded into a film or rod using a known method such as injection molding, extrusion molding or heat press. In particular, when it is processed into a film, it can be molded using various known techniques such as a casting method, a spin coating method, a bar coater method, and a die casting method. The thickness of the film is not particularly limited as long as it brings out the characteristics of the color dosimeter, but is preferably in the range of 0.01 to 10 mm.

  When the molded resin composition is irradiated with radiation, the color tone changes according to the radiation dose. The absorption dose of radiation can be estimated by measuring the absorption / transmission spectrum or reflection spectrum and measuring the amount of change in absorbance, transmittance or reflectance.

  The color dosimeter based on the arylamine derivative and tetrahalogenated methane or trihalogenated methane derivative of the present invention may be used in combination with an ultraviolet absorber in order to avoid coloring due to ambient light such as room light. Specifically, an ultraviolet absorber may be contained as one component of the composition, or an ultraviolet cut layer may be formed on the surface of a color dosimeter prepared from the composition.

The ultraviolet cut layer preferably cuts light having a wavelength of 100 to 450 nm to a light transmittance of 5% or less.
By adding an ultraviolet absorber or providing an ultraviolet cut layer, it is possible to prevent chemical reaction due to ultraviolet rays contained in ambient light, etc., other than the ionizing action due to radiation irradiation, and improve the accuracy of dose detection.

  In the present invention, since a composition containing an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative can be used, it is possible to provide a new color dosimeter that has not existed before.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples without departing from the gist thereof.
Example 1
In this example, N, N-diphenylamine was used as a representative example of an arylamine derivative, and the reaction with tetrahalogenated methane or various trihalogenated methane derivatives was examined. In this case, toluene was used as the solvent, and the respective concentrations were 0.3 mol / dm ³ for N, N-diphenylamine and 0.1 mol / dm ³ for the trihalogenated methane derivative.

Each sample was placed in a vial and irradiated. The irradiated radiation is gamma rays from a ⁶⁰ Co radiation source, and the irradiation dose is 5 Gy each. At this point, the colored state was visually evaluated, and further, visually evaluated after standing for 48 hours at room temperature in room light. The above results are shown in Table 1. In addition, all the prepared non-irradiated solutions were colorless and transparent.

From the results shown in Table 1, the change in hue of each of the solutions composed of the trihalogenated methane derivative and the N, N-diphenylamine derivative was confirmed by gamma irradiation.
Each colored sample was not changed even after 48 hours at room temperature in room light.

Example 2
In this example, bromoform was used as a representative example of a trihalogenated methane derivative, and the reaction with various arylamine derivatives was examined. Incidentally solvent in this case, using toluene each concentration was 0.1 mol / dm ³ in bromoform, the arylamine derivative was 0.3 mol / dm ^3. In addition, all the prepared unirradiated solutions were colorless and transparent.

The irradiated radiation is gamma rays from a ⁶⁰ Co radiation source, and the irradiation dose is 5 Gy each. At this point, the colored state was visually evaluated, and further, left for 48 hours in a dark place, then left for 48 hours for visual evaluation. The results are shown in Table 2.

  From the results shown in Table 2, the change in hue of each solution composed of bromoform and various arylamine derivatives was confirmed by gamma irradiation.

Example 3
40 wt% polystyrene (solvent toluene) is added in equal weights to the sample prepared in Example 1 that can be in a solid state even in the absence of solvent (sample 3, samples 7-9). A coating solution was prepared. Each solution was dropped on a PET film to form a film by removing the solvent, and this was irradiated with X-rays at 5 Gy (tube voltage 5 keV, tube current 20 mA). At this time, the colored state was visually evaluated, and further, left for 48 hours in a dark place, and then visually evaluated. The results are shown in Table 3.

  In addition, all the prepared films without irradiation were colorless and transparent.

  From the results shown in Table 3, changes in hue were confirmed by X-ray irradiation.

Comparative Example 1
In the same manner as in Example 1, N, N-diphenylamine was used as a representative example of the arylamine derivative, and the reaction with various halides was examined. The concentration and solvent were the same as in Example 1.

The irradiated radiation is gamma rays from a ⁶⁰ Co radiation source, and the irradiation dose is 5 Gy each. The above results are shown in Table 4.

  From the results in Table 4, none of the samples was colored. This indicates that dihalogenated methane derivatives are not suitable as halides that exhibit color reaction by radiation chemical reaction with arylamine derivatives.

Comparative Example 2
In the same manner as in Example 2, bromoform was used as a representative example of the trihalogenated methane derivative, and the reaction with various amine derivatives was examined. The concentration and solvent were the same as in Example 2.

The irradiated radiation is gamma rays from a ⁶⁰ Co radiation source, and the irradiation dose is 5 Gy each. The results are shown in Table 5.

  From the results in Table 5, it can be seen that amine derivatives that do not have an aryl group are inappropriate as amine derivatives that exhibit a color-forming reaction by radiation chemical reaction with a trihalogenated methane derivative.

Comparative Example 3
Three points of 100 g of a butyl acetate solution of polyvinyl chloride as an organic halide (concentration 37 wt%) were prepared, and 0.04 g, 0.40 g, and 0.80 g of methyl yellow as a pH indicator were dissolved separately. Each of these solutions was coated on a PET film with a 0.2 mm applicator, and the solvent was removed on a hot plate at 80 ° C. over 30 minutes to prepare a film sample. Two samples of each were prepared, and X-rays were irradiated with 5 Gy and 5000 Gy (tube voltage 5 keV, tube current 20 mA). The results are shown in Table 6.

  From the results in Table 6, it can be seen that the color development reaction of the pH indicator using the radiolysis reaction of polyvinyl chloride, which is an organic halide, requires irradiation of about 5000 Gy. Therefore, it is impossible to detect radiation irradiation of about several Gy.

Comparative Example 4
0.19 g of 10,12-pentacosadiynoic acid was dissolved in 2 mL of toluene. 2 μL of this was dropped onto glossy inkjet paper, and the solvent was removed over 30 minutes on a hot plate at 80 ° C. to prepare a film sample.

  This sample was irradiated with X-rays at 5 Gy (tube voltage 5 keV, tube current 20 mA). At this time, the colored state was visually evaluated, and further, visually evaluated after being left in a dark place for 48 hours. The results are shown in Table 7. As can be seen from this result, discoloration does not end even after irradiation, suggesting that it is impossible to evaluate doses with excellent immediacy.

  In the present invention, it is possible to easily prepare a highly sensitive color dosimeter by using an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative, and by manipulating each substituent. It can be used as a color dosimeter capable of adjusting the color change.

Claims (3)

  A color dosimeter for detecting radiation by color development by a chemical reaction, comprising at least an arylamine derivative and a tetrahalogenated methane or trihalogenated methane derivative, and radiation by coloration generated by irradiating the derivative with radiation Color dosimeter characterized by detecting The color dosimeter according to claim 1, wherein the arylamine derivative is composed of a compound represented by the following general formula (1).

(In the formula, Ar represents an aryl group. R 1 and R 2 represent a hydrogen atom, an alkyl group, or an aryl group.) The color dosimeter according to claim 1, wherein the trihalogenated methane derivative is composed of a compound represented by the following general formula (2).

(In the formula, X represents one or more halogen atoms selected from a chlorine atom, a bromine atom and an iodine atom. R represents a hydrogen atom, an alkyl group or an aryl group.)