JPH11352300A - Radiation image conversion panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image conversion panel having low degradation in sensitivity for repeated irradiations of radiation such as X-ray. SOLUTION: A radiation image conversion panel, having fluorescent layer consisting of accelerated fluorescent body, is of fluorescent body containing iodine. For antioxidant, accelerated fluorescent body contains epoxy compound, diethyl phosphite and a compound selected from among a group of hindered phenol compounds, hindered amine compounds and thioether compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image conversion panel used for a radiation image recording / reproducing method using a stimulable phosphor.

[0002]

2. Description of the Related Art A radiation image recording / reproducing method using a stimulable phosphor is known as an alternative to the conventional radiographic method. This method uses a radiation image conversion panel (a stimulable phosphor sheet) containing a stimulable phosphor, and transmits radiation transmitted through a subject or emitted from a subject to the stimulable phosphor of the panel. The radiation energy stored in the stimulable phosphor is absorbed by the body in a time-series manner by exciting the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared rays. The fluorescent light is emitted as (stimulated emission light), the fluorescence is read photoelectrically to obtain an electric signal, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal. After the reading, the panel is prepared for the next photographing after the remaining image is erased. That is, the radiation image conversion panel is used repeatedly.

According to this radiographic image recording / reproducing method, a radiographic image having a large amount of information can be obtained with a much smaller exposure dose than the conventional radiographic method using a combination of a radiographic film and an intensifying screen. There is an advantage that can be. Furthermore, in contrast to the conventional radiographic method, which consumes a radiographic film for each photographing operation, the radiographic image recording / reproducing method uses a radiographic image conversion panel repeatedly, so that resource conservation and economic efficiency are reduced. Is also advantageous.

The radiation image conversion panel used in the radiation image recording / reproducing method has, as a basic structure, a support and a stimulable phosphor layer provided on the surface of the support. However, when the stimulable phosphor layer is self-supporting, a support is not necessarily required. Also, a protective film is usually provided on the surface of the stimulable phosphor layer (the surface not facing the support) to protect the phosphor layer from chemical alteration or physical impact. ing.

The stimulable phosphor layer usually comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. However, there is also known a stimulable phosphor layer which does not include a binder formed by a vapor deposition method or a sintering method and is composed of only an aggregate of the stimulable phosphor. Further, there is known a radiation image conversion panel having a stimulable phosphor layer in which a polymer substance is impregnated in a gap between stimulable phosphor aggregates. In any of these phosphor layers, the stimulable phosphor is X
When irradiated with excitation light after absorbing radiation such as radiation, it has the property of stimulating luminescence, so radiation transmitted through a subject or emitted from a subject is proportional to the amount of radiation. Absorbed by the stimulable phosphor layer of the image conversion panel, a radiation image of the subject or the subject is formed on the panel as an accumulated image of radiation energy. This accumulated image can be emitted as stimulated emission light by irradiating the excitation light, and the accumulated image of radiation energy is imaged by photoelectrically reading the stimulated emission light and converting it into an electric signal. Can be realized.

Although the radiation image recording / reproducing method has many excellent advantages as described above, the radiation image conversion panel used in this method has the highest sensitivity and the highest image quality (sharpness). It is desired to provide an image having good image quality (degree, graininess, etc.).

Conventionally, when an iodine-containing stimulable phosphor is used, iodine is liberated from the stimulable phosphor due to environmental conditions such as temperature and humidity after the production of the radiation image conversion panel or after the production. For the purpose of preventing yellowing,
JP-A-31907 describes that a stimulable phosphor layer contains a compound having an epoxy group.
JP-A-31909 describes that a stimulable phosphor layer contains a compound having an epoxy group and at least one compound selected from the group consisting of phosphites, organotin compounds and metal salts of organic acids. Have been. Also,
U.S. Pat. No. 5,630,963 describes that a hindered amine compound is contained.
Further, Japanese Patent Application No. 8-353612 filed by the present applicant discloses, for the purpose of improving light resistance against visible light and the like,
It has been proposed that a stimulable phosphor layer contain a hindered amine compound or a hindered phenol compound.

[0008]

SUMMARY OF THE INVENTION The present inventors have found that the sensitivity of a radiation image conversion panel containing the above-described compound gradually decreases when it is repeatedly used. That is, besides the change in environmental conditions and the decrease in sensitivity due to visible light irradiation, the sensitivity of the panel gradually decreases when radiation such as X-rays is repeatedly applied to the panel many times during radiation imaging, or when the panel is irradiated for a long time. I found something new. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a radiation image conversion panel in which the sensitivity is less reduced with respect to repeated irradiation of radiation such as X-rays. In addition, the present invention provides a radiation image conversion panel that has a small decrease in sensitivity not only to irradiation of radiation such as X-rays, but also to changes in environmental conditions after the production of the panel and after production, and to irradiation of ultraviolet rays and visible light. To provide.

[0009]

The inventor of the present invention has conducted studies on the reduction in sensitivity of the radiation image conversion panel due to repeated use, and as a result, the stimulable fluorescence of the panel has been reduced even by repeated irradiation of radiation such as X-rays. It has been found that iodine is liberated from the body to form iodine molecules (I ₂ ) and the sensitivity gradually decreases due to yellowing of the stimulable phosphor layer. Therefore, in addition to the epoxy compound and the phosphite as an antioxidant in the stimulable phosphor layer, at least one compound selected from the group consisting of hindered phenol compounds, hindered amine compounds and thioether compounds, and furthermore The addition of the organometallic composite stabilizer not only deteriorates the stimulable phosphor due to environmental conditions such as temperature and humidity or visible light irradiation, but also deteriorates the stimulable phosphor due to irradiation with radiation such as X-rays. The inventors have found that the sensitivity can be kept higher than before even when the number of uses is increased, thereby achieving the present invention.

According to the present invention, there is provided a radiation image conversion panel having a phosphor layer comprising a stimulable phosphor, wherein the stimulable phosphor is a phosphor containing iodine, and the stimulable phosphor layer is provided. Is an antioxidant (1) an epoxy compound,
A radiation image conversion panel comprising (2) a phosphite and (3) at least one compound selected from the group consisting of a hindered phenol compound, a hindered amine compound and a thioether compound.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the radiation image storage panel of the present invention will be described below. (1) A radiation image conversion panel in which the stimulable phosphor layer contains an epoxy compound, a phosphite and a hindered phenol compound. (2) A radiation image conversion panel in which the stimulable phosphor layer contains an epoxy compound, a phosphite, a hindered phenol compound and a thioether compound. (3) A radiation image conversion panel in which the stimulable phosphor layer contains an epoxy compound, a phosphite, a hindered phenol compound, a thioether compound, and an organic metal composite stabilizer. (4) The epoxy compound is stimulable, and 0.0
A radiation image storage panel which is contained in an amount ranging from 01 to 10% by weight, preferably from 0.03 to 3% by weight. (5) An antioxidant other than an epoxy compound, and further, an organometallic composite stabilizer is used in an amount of 0.0001 to 0.001 to the stimulable phosphor.
3% by weight, preferably 0.003-0.3% by weight
Radiation image conversion panel included in an amount in the range of. (6) A radiation image conversion panel in which the stimulable phosphor is a europium or cerium-activated alkaline earth metal halide-based phosphor containing iodine or a cerium-activated rare earth oxyhalide-based phosphor containing iodine. (7) A radiation image conversion panel wherein the stimulable phosphor layer is substantially composed of a binder containing and supporting the stimulable phosphor, and the binder is a resin containing a thermoplastic elastomer as a main component.

Next, a method for manufacturing the radiation image storage panel of the present invention will be described in detail. The support can be arbitrarily selected from materials known as supports for conventional radiation image storage panels. In a known radiation image conversion panel,
In order to strengthen the bond between the support and the stimulable phosphor layer or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel, the surface of the support on which the phosphor layer is provided A polymer material such as gelatin is applied to the surface to provide an adhesion-imparting layer, or a light-reflective layer made of a light-reflective material such as titanium dioxide or a light-absorbing layer made of a light-absorbing material such as carbon black is provided. It is known. The support used in the present invention can also be provided with these various layers, and the configuration thereof can be arbitrarily selected according to the desired purpose and application of the radiation image storage panel. Further, JP-A-58-
As described in JP-A-200200, in order to improve the sharpness of an obtained image, the surface of the support on the side of the phosphor layer (the surface of the support on the side of the phosphor layer, the adhesion-imparting layer, the light reflection layer, When an auxiliary layer such as a layer or a light absorbing layer is provided, the surface of the auxiliary layer may be provided). When the stimulable phosphor layer is self-supporting, it is not always necessary to use a support.

A stimulable phosphor layer is provided on the support. The stimulable phosphor layer, which is a characteristic requirement of the present invention, contains a stimulable phosphor containing iodine, an antioxidant for preventing deterioration of the stimulable phosphor layer, and the like. The case where the stimulable phosphor layer is composed of a binder that contains and supports these stimulable phosphors and an antioxidant in a dispersed state will be described as an example.

The stimulable phosphor containing iodine used in the present invention contains iodine as a composition of the phosphor, that is, as a base component, an additive component and / or an activator component of the phosphor. The stimulable phosphor containing iodine is
As described above, a phosphor that emits stimulated light when irradiated with excitation light after being irradiated with radiation. However, from a practical point of view, a wavelength of 300 to 500 nm is generated by excitation light having a wavelength in the range of 400 to 900 nm. It is desirable that the phosphor exhibit stimulable luminescence in a range. Examples of the iodine-containing stimulable phosphor include those described in detail in JP-A-2-193100 and JP-A-4-310900.

Among the known stimulable phosphors, iodine-containing europium or cerium-activated alkaline earth metal halide-based phosphors and iodine-containing cerium-activated rare earth oxyhalide-based phosphors are high. It is particularly preferable because it exhibits stimulated emission of luminance. However, the iodine-containing stimulable phosphor used in the present invention is not limited to the above-described phosphor, and contains iodine as a phosphor composition.
Further, any phosphor may be used as long as the phosphor emits stimulated emission when the irradiated radiation is accumulated and irradiated with excitation light at an arbitrary time thereafter.

In the present invention, the antioxidant contained in the stimulable phosphor layer for preventing deterioration of the stimulable phosphor layer is an epoxy compound, a phosphite, a hindered phenol compound, a hindered amine. And at least one compound selected from the group consisting of thioether compounds and thioether compounds. Further, an organometallic composite stabilizer is optionally added.

These antioxidants and stabilizers are used in the course of the production of the stimulable phosphor layer or in environmental conditions such as temperature and humidity after the production, irradiation of ultraviolet light or visible light, and further radiation such as X-rays. Irradiation can efficiently capture iodine released from the stimulable phosphor. That is, the epoxy compound and the phosphite are mainly
It is effective for capturing iodine released due to environmental conditions such as high temperature and high humidity at the time of coating formation of the stimulable phosphor layer and after the formation,
On the other hand, hindered phenol compounds, hindered amine compounds, thioether compounds and / or organometallic compound stabilizers are mainly used for capturing iodine released due to irradiation with ultraviolet rays or visible light and irradiation with radiation such as X-rays. It is valid. And, by using these mixtures, iodine can be captured very effectively not only by environmental conditions and light irradiation, but also by radiation irradiation. In particular, by using a mixture of an epoxy compound, a phosphite, a hindered phenol compound, a thioether compound and an organic metal composite stabilizer as an antioxidant, iodine can be captured extremely efficiently. This prevents the formation of I ₂ molecules and prevents the stimulable phosphor layer from discoloring to yellow.

The epoxy compound may be a monomer such as 1,2-epoxypropane or 1,2-epoxybutane, or may be a polymer such as a bisphenol A type epoxy resin. When the epoxy compound is a polymer, a polymer such as a bisphenol A-type epoxy resin is preferable because it functions as an antioxidant and also as a binder.

Examples of phosphites include triphenyl phosphite, diphenyl decyl phosphite, didecyl phenyl phosphite, tridecyl phosphite, trioctyl phosphite, tridodecyl phosphite, trioctadecyl phosphite, trinonyl Phenyl phosphite, and tridodecyl trithio phosphite can be mentioned.

Various products are commercially available for hindered phenol compounds, hindered amine compounds and thioether compounds. For example, as a hindered phenol compound, IRGANOX1010
(Chivas Specialty Chemicals Co., Ltd.), ADK STAB AO-20, AO-30, AO-40, AO
-50, AO-60, AO-70, AO-75,
AO-80 and AO-330 (above, Adeka Argus Chemical Co., Ltd.). Examples of the hindered amine compounds include SANOL LS-744, LS-770, LS-765, and LS-2626 (hereinafter Sankyo Co., Ltd.), Mark LA-77, LA-57, and LA-
67, the same LA-62, the same LA-68, the same LA-63 (Adeka Argus Chemical Co., Ltd.), tinuvin 144,
Tinuvin 622LD, Chimasorb 944FL (or
LD) (above, Ciba-Geigy), Siasorb UV
3346 (American Cyanamide), Spinubex A-36 (Monte Edison) and the like. Also,
As thioether compounds, ADK STAB AO-5
03A (Asahi Denka Co., Ltd.).

The organometallic composite stabilizer mainly comprises a metal salt of a long-chain fatty acid, so-called metal soap. Examples of long chain fatty acids include stearic acid, lauric acid, ricinoleic acid, naphthenic acid and 2-ethylhexoic acid. Examples of the metal used for the long-chain fatty acid metal salt include calcium, zinc, tin and barium.

The content of the antioxidant and the stabilizer varies depending on the type of the stimulable phosphor, the combination of the antioxidant and the like, the type of the binder, and the like. It is in the range of 0.001 to 10% by weight, preferably 0.03 to 3% by weight, based on the luminescent phosphor. The content of the remaining antioxidants and stabilizers such as phosphite is generally in the range of 0.0001 to 3% by weight, preferably 0.003 to 0.1% by weight, based on the stimulable phosphor. It is in the range of 3% by weight.

Examples of the binder include proteins such as gelatin, polysaccharides such as dextran, and natural high molecular substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethylcellulose, vinylidene chloride and vinyl chloride. Copolymer, polyalkyl (meth) acrylate, vinyl chloride
Synthetic polymeric substances such as vinyl acetate copolymers, polyurethanes, cellulose acetate butyrate, polyvinyl alcohol, linear polyesters, thermoplastic elastomers and the like can be mentioned. Of these, a softening temperature of 30 to 150 ° C. and 0.3 kgf / m 2 are preferable.
It is a thermoplastic elastomer such as a polyurethane elastomer having an elastic modulus of m ² or less. In addition, these binders may be cross-linked by a cross-linking agent.

The stimulable phosphor layer can be formed on a support, for example, by the following method. First, a stimulable phosphor, a binder, and an antioxidant are added to a solvent,
This is sufficiently mixed to prepare a coating solution in which the stimulable phosphor and the antioxidant are uniformly dispersed in the binder solution. Examples of the solvent for preparing the coating solution include lower alcohols such as methanol, ethanol, n-propanol and n-butanol; hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone. Esters of lower fatty acids such as methyl acetate, ethyl acetate, and butyl acetate with lower alcohols; ethers such as dioxane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, and tetrahydrofuran; and mixtures thereof.

The mixing ratio between the binder and the stimulable phosphor in the coating solution varies depending on the desired characteristics of the radiation image conversion panel, the type of the phosphor, and the like. Is selected in the range of 1: 1 to 1: 100 (weight ratio), and particularly preferably in the range of 1: 8 to 1:40 (weight ratio). In addition, in the coating liquid,
Various dispersants such as a dispersant for improving the dispersibility of the phosphor in the coating solution, and a plasticizer for improving the bonding force between the binder and the phosphor in the phosphor layer after formation. Additives may be mixed.

The stimulable phosphor thus prepared,
A coating solution containing an antioxidant and the like, and a binder,
A coating film is formed by uniformly coating the surface of the support. This coating operation can be performed by a method using ordinary coating means, for example, a doctor blade, a roll coater, a knife coater, or the like.

After forming a coating film on the support as described above, the coating film is dried to complete the formation of the stimulable phosphor layer on the support. The thickness of the stimulable phosphor layer varies depending on the intended characteristics of the radiation image conversion panel, the type of the phosphor, the mixing ratio between the binder and the phosphor, and is usually 20 μm.
１1 mm, preferably 50-500 μm. Note that the phosphor layer does not necessarily need to be formed by directly applying a coating liquid on the support as described above,
For example, a phosphor layer is formed by separately applying a coating solution onto a sheet such as a glass plate, a metal plate, and a plastic sheet and drying, and then pressing the phosphor layer on a support or using an adhesive. A method of joining a phosphor layer on a support may be used.

The stimulable phosphor layer of the radiation image storage panel of the present invention comprises not only a stimulable phosphor and an antioxidant but also a binder containing and supporting the stimulable phosphor in a dispersed state. Composed of aggregates of stimulable phosphor and antioxidant, etc. without containing an agent, or those in which antioxidants, etc. and polymer substances are impregnated in the gaps between aggregates of stimulable phosphor, etc. It may be.

A transparent protective film may be provided on the surface of the stimulable phosphor layer on the side opposite to the side in contact with the support to physically and chemically protect the phosphor layer. As the protective film, a solution prepared by dissolving a transparent organic polymer material such as a cellulose derivative, polymethyl methacrylate, or an organic solvent-soluble fluororesin in an appropriate solvent is applied onto the phosphor layer. Formed, or an organic polymer film such as polyethylene terephthalate, or a protective film forming sheet such as a transparent glass plate, separately formed and provided on the surface of the phosphor layer using a suitable adhesive, or inorganic What formed the compound on the fluorescent substance layer by vapor deposition etc. is used. In the protective film, light scattering fine particles such as magnesium oxide, zinc oxide, and titanium oxide,
Various additives such as a slipping agent such as a perfluoroolefin resin powder and a silicone resin powder and a crosslinking agent such as a polyisocyanate may be dispersedly contained. The thickness of the protective film is generally in the range of about 0.1 to 20 μm.

Although the radiation image conversion panel of the present invention is obtained as described above, the configuration of the panel of the present invention may include various known variations. For example, for the purpose of improving the sharpness of the obtained image, at least one of the above-mentioned layers may be colored with a coloring agent that absorbs excitation light but does not absorb stimulating light (Japanese Patent Publication No. No. 59-23400).

[0031]

[Example 1] (1) Preparation of phosphor sheet Phosphor: BaFBr _0.85 I _0.15 : Eu ²⁺ 200g Binder: polyurethane elastomer (T-5205 [solid], Dainippon Ink & Chemicals, Inc.) 7.0 g Crosslinker: Polyisocyanate (Sumidur N3200 [solid], manufactured by Sumitomo Bayer Urethane Co., Ltd.) 1.5 g Antioxidant: epoxy resin (EP1004 [solid], manufactured by Yuka Shell Epoxy Co., Ltd.) 1.5 g Phosphorous ester (diphenyldecyl phosphite) 0.05 g Hindered phenol compound (IRGANOX1010, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 g

The material having the above composition was added to methyl ethyl ketone and dispersed with a propeller mixer to give a viscosity of 30 PS (25
° C) was prepared (binder / phosphor ratio = 1/2).
0). This was applied on polyethylene terephthalate (temporary support, 150 μm thickness) coated with a silicone release agent, dried, and then peeled off from the temporary support to form a phosphor sheet (200 μm thickness).

(2) Formation of Undercoat Layer Binder: Soft acrylic resin 90 g (solid content) Nitrocellulose 50 g (solid content) The material having the above composition was added to methyl ethyl ketone, and mixed with a propeller mixer to give a viscosity of 3 ~ 6PS (25 ℃)
A coating solution for forming an undercoat layer was prepared. Polyethylene terephthalate (support) having a thickness of 300 μm is placed horizontally on a glass plate, and this coating solution is uniformly applied on the support using a doctor blade. After that, the coating film is dried and the undercoat is applied on the support. A layer (layer thickness: 15 μm) was formed.

(3) Addition of stimulable phosphor layer The phosphor sheet prepared above was placed on the surface of the undercoat layer on the support and compressed. The compression operation was performed using a calendar roll at a pressure of 500 kgw / cm ² and an upper roll temperature of 75.
° C, lower roll temperature 25 ° C, feed rate 0.3m /
This was performed continuously under the conditions of minutes. By this heat compression, the phosphor sheet was completely fused to the support to provide a stimulable phosphor layer.

(4) Formation of protective film Fluorine resin: fluoroolefin / vinyl ether copolymer (Lumiflon LF-504X (40% solution), manufactured by Asahi Glass Co., Ltd.) 50 g Crosslinking agent: polyisocyanate (Olester NP38-70S) (70% solution), Mitsui Toatsu Chemical Co., Ltd. 9 g Slipper: alcohol-modified silicone (X-22-2809 (66% solution), Shin-Etsu Chemical Co., Ltd.) 0.5 g Catalyst: dibutyltin dilaurate (KS1260, Kyodo Yakuhin Co., Ltd.) 3mg

The material having the above composition was prepared by adding methyl ethyl ketone /
It was dissolved in cyclohexane (2/8, volume ratio) to prepare a coating liquid for forming a protective film having a viscosity of 0.2 to 0.3 PS (25 ° C.). This coating solution was applied onto the stimulable phosphor layer using a doctor blade, and then heat-treated at 120 ° C. for 30 minutes, thermally cured, and dried to provide a protective film having a thickness of 3 μm.

(5) Formation of border paste Silicone polymer (polyurethane having polydimethylsiloxane unit, dialomer SP-3023 (15 wt% solution (solvent: mixed solvent of methyl ethyl ketone and toluene), manufactured by Dainichi Seika Co., Ltd.) 70 g Crosslinking agent: polyisocyanate (Crosnate D-70 (50 wt% solution), manufactured by Dainichi Seika Co., Ltd.) 3 g Antioxidant: epoxy resin (EP1001 [solid], manufactured by Yuka Shell Epoxy Co., Ltd.) 0.6 g Slip agent: alcohol-modified silicone (X-22-2809 (66% solution), manufactured by Shin-Etsu Chemical Co., Ltd.) 0.2 g

The material having the above composition was replaced with methyl ethyl ketone 15
g and dissolved to prepare a coating solution for forming an edge patch. This coating solution is applied to each side of the laminate composed of the support, the undercoat layer, the stimulable phosphor layer, and the protective film prepared above, and dried sufficiently at room temperature. A cured adhesive film was formed to produce a radiation image conversion panel composed of a support, an undercoat layer, a stimulable phosphor layer, a protective film, and a cured edge-coated film.

[Example 2] In Example 1, as an antioxidant, an epoxy resin (EP1004 [solid], manufactured by Yuka Shell Epoxy Co., Ltd.) 1.5 g of a phosphite and a hindered phenol compound A radiation image conversion panel of the present invention was manufactured in the same manner as in Example 1 except that 0.1 g of a 1: 1 weight ratio mixture (IRGANOX LC20, FF, manufactured by Ciba Specialty Chemicals Co., Ltd.) was used.

[Example 3] In Example 1, as an antioxidant, an epoxy resin (EP1004 [solid], manufactured by Yuka Shell Epoxy Co., Ltd.) 1.5 g of a phosphite and a hindered phenol compound : 1 weight ratio mixture (IRGANOX LC20, FF, Ciba Specialty Chemicals Co., Ltd.) 0.07 g Thioether-based compound (ADK STAB AO-503A, Asahi Denka Co., Ltd.) 0.13 g In the same manner as in Example 1, a radiation image storage panel of the invention was manufactured.

Example 4 In Example 1, as an antioxidant, an epoxy resin (EP1004 [solid], manufactured by Yuka Shell Epoxy Co., Ltd.) 1.5 g of a phosphite and a hindered phenol compound : 1 weight ratio mixture (IRGANOX LC20, FF, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 g Thioether-based compound (ADK STAB AO-503A, manufactured by Asahi Denka Co., Ltd.) 0.1 g Organometallic composite stabilizer (zinc, A radiation image storage panel of the present invention was manufactured in the same manner as in Example 1 except that 0.05 g of calcium-based metal soap (KV-73A-4, manufactured by Kyodo Yakuhin Co., Ltd.) was used.

[Example 5] In Example 1, as an antioxidant, an epoxy resin (EP1004 [solid], manufactured by Yuka Shell Epoxy Co., Ltd.) 1.5 g of a phosphite and a hindered phenol compound : 1 weight ratio mixture (IRGANOX LC20, FF, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 g Thioether-based compound (ADK STAB AO-503A, manufactured by Asahi Denka Co., Ltd.) 0.1 g Organometallic composite stabilizer (zinc, A radiation image storage panel of the present invention was manufactured in the same manner as in Example 1 except that 0.05 g of calcium-based metal soap (KV-67W-3, manufactured by Kyodo Yakuhin Co., Ltd.) was used.

Comparative Example 1 A radiation image conversion panel for comparison was manufactured in the same manner as in Example 1 except that the phosphite and the hindered phenol compound were not added. .

Comparative Example 2 A radiation image conversion panel for comparison was manufactured in the same manner as in Example 1 except that the hindered phenol compound was not added.

[Evaluation of Performance of Radiation Image Conversion Panel] Each of the obtained radiation image conversion panels was tested for sensitivity and radiation resistance, and its performance was evaluated. (1) Sensitivity test After irradiating a radiation image conversion panel of a sample with X-rays having a tube voltage of 80 kVp, He-Ne laser light (wavelength: 632.8)
nm), the amount of stimulated emission from the radiation image conversion panel was measured, and the sensitivity (initial sensitivity) was indicated by the relative value of the amount of emitted light.

(2) Radiation-resistant property test The radiation image conversion panel was irradiated with a total of 3000R X-rays at a tube voltage of 80 kVp, and then irradiated with a sodium lamp to completely erase the X-ray image information. After the panel was allowed to stand at 25 ° C. for 7 days, the sensitivity (sensitivity after massive irradiation of X-rays) was measured in the same manner as above, and the sensitivity / initial sensitivity after massive irradiation of X-rays was displayed as a radiation-resistant characteristic value. The value 1.0
Means that there is no decrease in sensitivity due to the large amount of X-ray irradiation. Table 1 summarizes the obtained results.

[0047]

[Table 1] Table 1 ─────────────────────────────────── Initial sensitivity Radiation resistance characteristic value ─── ──────────────────────────────── Example 1 100 0.79 2 102 0.80 3 101 0.81 4 98 0.83 5 99 0.82 {Comparative Example 1 100 0. 68 2 101 0.75 ───────────────────────────────────

From the results shown in Table 1, the initial sensitivity of the radiation image conversion panel of the present invention (Examples 1 to 5) is almost the same as that of the conventional radiation image conversion panel (Comparative Examples 1 and 2). In addition, it is clear that the decrease in sensitivity due to the massive irradiation of X-rays corresponding to the number of uses of several thousand to several tens of thousands of times is reduced, and that the radiation resistance is improved. Further, the radiation image conversion panel of the present invention is a manufacturing process and environmental conditions such as temperature and humidity,
In addition, there was almost no decrease in sensitivity due to light in the ultraviolet to visible region, and the film was excellent.

[0049]

According to the present invention, a stimulable phosphor layer of a radiation image conversion panel using an iodine-containing stimulable phosphor may contain, in addition to an epoxy compound and a phosphite, a hindered phenol compound or the like. Further, by including the organometallic composite stabilizer, even if the number of times of imaging is increased, a decrease in sensitivity can be suppressed to be smaller than before, and the radiation resistance can be improved. Panel production processes and changes in environmental conditions such as temperature and humidity, as well as an increase in the integrated irradiation amount of ultraviolet and visible light due to repeated use, and an increase in the integrated irradiation amount of radiation such as X-rays. Yellowing can be effectively prevented, and a decrease in sensitivity can be minimized.

Claims (10)

[Claims] 1. A radiation image conversion panel having a phosphor layer made of a stimulable phosphor, wherein the stimulable phosphor is a phosphor containing iodine, and the stimulable phosphor layer is an antioxidant. A radiation image conversion panel comprising, as an agent, an epoxy compound, a phosphite, and at least one compound selected from the group consisting of a hindered phenol compound, a hindered amine compound and a thioether compound. 2. The radiation image storage panel according to claim 1, wherein the stimulable phosphor layer contains an epoxy compound, a phosphite, and a hindered phenol compound. 3. The radiation image conversion panel according to claim 1, wherein the stimulable phosphor layer contains an epoxy compound, a phosphite, a hindered phenol compound, and a thioether compound. 4. The radiation image storage panel according to claim 1, wherein the stimulable phosphor layer further contains an organometallic composite stabilizer. 5. The method according to claim 1, wherein the epoxy compound is contained in an amount of 0.001 to 10% by weight based on the stimulable phosphor.
5. The radiation image conversion panel according to any one of items 4 to 4. 6. The radiation image storage panel according to claim 5, wherein the epoxy compound is contained in a range of 0.03 to 3% by weight based on the stimulable phosphor. 7. The stimulable phosphor layer contains an antioxidant other than the epoxy compound and an organometallic composite stabilizer in an amount of 0.0001 to 3% by weight based on the stimulable phosphor. The radiation image conversion panel according to claim 1. 8. The stimulable phosphor layer comprises an antioxidant other than an epoxy compound and an organometallic composite stabilizer in an amount of 0.003 to 0.3% by weight based on the stimulable phosphor. The radiation image conversion panel according to any one of claims 1 to 6, comprising: 9. The stimulable phosphor is an iodine-containing europium or cerium-activated alkaline earth metal halide-based phosphor, or an iodine-containing cerium-activated rare earth oxyhalide-based phosphor. 9. The radiation image conversion panel according to any one of items 1 to 8. 10. The stimulable phosphor layer substantially comprises a stimulable phosphor and a binder for binding and supporting the stimulable phosphor, and the binder is a resin containing a thermoplastic elastomer as a main component. 10. The radiation image conversion panel according to any one of items 1 to 9.