JP2825497B2 - Radiation image conversion panel - Google Patents

Description

The present invention relates to a radiation image conversion panel having a stimulable phosphor layer, and more particularly, to a radiation image conversion panel which is not deteriorated by invasion of moisture. The present invention relates to a radiation image conversion panel having a stimulable phosphor layer having excellent initial performance.

(Prior Art) Radiation images such as X-ray images are widely used for diagnosis of diseases and the like.

In order to obtain the X-ray image, an X-ray image conversion method for directly extracting an image from the phosphor layer instead of the silver halide photosensitive material has been devised.

This method uses radiation transmitted through the subject (generally X-rays)
Is absorbed by the phosphor, and thereafter, the phosphor is excited by, for example, light or heat energy to cause the phosphor to emit radiation energy accumulated by the radiation absorption as fluorescence, and the fluorescence is detected. This is a method of imaging.

Specifically, for example, U.S. Pat. No. 3,859,527 and JP-A-55-12144 show a radiation image conversion method using a stimulable phosphor and using visible light or infrared light as stimulating excitation light.

This method uses a radiation image conversion panel (hereinafter abbreviated as a conversion panel) having a stimulable phosphor layer (hereinafter abbreviated as a stimulable layer).
The latent image is formed by applying radiation transmitted through the subject to the stimulating layer of the conversion panel, accumulating radiation energy corresponding to the radiation transmittance of each part of the subject, and then forming the stimulating layer. By scanning with stimulating excitation light, the radiation energy stored in each section is emitted and converted into light, and an image is obtained by an optical signal based on the intensity of the light.

This final image may be reproduced as a hard copy or reproduced on a CRT.

The conversion panel used in this radiation image conversion method emits stored energy by scanning with stimulating excitation light after accumulating radiation image information, and the radiation image can be accumulated again after scanning, Can be used repeatedly.

Therefore, it is desirable that the conversion panel has a performance that can withstand long-term use or repeated use many times without deteriorating the image quality of the obtained radiation image. For this purpose, the photostimulable layer of the conversion panel needs to be sufficiently protected from external physical or chemical stimuli.

In the conventional conversion panel, in order to solve the above-mentioned problem, a method of providing a protective layer for covering the stimulable layer surface on the support of the conversion panel has been adopted.

This protective layer is formed by directly applying a protective layer coating solution on the photostimulable layer, as described in, for example, JP-A-59-42500, or a protective layer formed separately in advance. It is formed by a method of bonding on the photostimulable layer.

As the protective layer, a thin protective layer (about 10 μm thick) made of an organic polymer is generally used.

(Problem to be solved) However, a thin protective layer made of a commonly used organic polymer is permeable to a certain amount of moisture, moisture, etc.
The stimulable layer absorbs moisture, resulting in a decrease in radiation sensitivity of the conversion panel or a large attenuation of stored energy until irradiated with stimulating excitation light, resulting in unevenness and deterioration in the image quality of the obtained radiation image. .

When using a conversion panel having such a thin protective layer under severe temperature and humidity conditions, or when using a conversion panel using a stimulable phosphor that does not have sufficient resistance to moisture, the protective layer Deterioration of the photostimulable layer due to a small amount of moisture that penetrates and penetrates the film has become a problem. For example, in the case of a polyethylene terephthalate (PET) film having a thickness of 10 μm, which is a commonly used protective layer, its moisture permeability is 60 g / m ² · 24 hr, and as much as 60 g of water per unit area per day.

Further, in the conventional conversion panel having a thin protective layer as described above, since the surface hardness of the protective layer is small, the protective layer surface may be damaged by contact with a mechanical part such as a transport roller during transport, or the protective layer may be thin. Since the protective layer has insufficient impact resistance, cracks and breaks are apt to occur in the photostimulable layer, and the quality of the obtained radiation image deteriorates as it is used repeatedly.

Such a conversion panel is manufactured by sealing a peripheral portion of a laminate including a support, a photostimulable layer, and a protective layer in order to further improve moisture resistance. As a sealing method,
For example, a method in which only the periphery of the conversion panel is immersed in an organic polymer solution, or an organic polymer solution is applied to the periphery to form a polymer film and seal, and the periphery is sealed with a sealant. Then, a method of fixing the sealant from the outside with a fixing component (Japanese Patent Application Laid-Open No. 61-237099), a method of sealing in a state where the peripheral portion is covered with an extended portion of the protective layer (Japanese Patent Application Laid-Open No. 61-237100) Gazette) is used.

However, the effect of moisture permeating the protective layer on the photostimulable layer cannot be sufficiently prevented only by sealing in this manner.

Therefore, an object of the present invention is to provide a radiation image conversion panel in which the stimulable phosphor is prevented from deteriorating due to intrusion of moisture, and has improved initial performance and durability.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to a radiation image conversion panel having a stimulable phosphor layer between a support and a protective layer, wherein the stimulable phosphor layer is A protective layer holding member that surrounds the periphery and seals the stimulable phosphor between the support and the protective layer, and a sealing member with low moisture permeability that seals the protective layer holding member from the outside. A radiation image conversion panel, wherein the protective layer holding member has a higher hygroscopic property than the stimulable phosphor. FIG. 1 schematically shows an example of the conversion panel of the present invention, wherein 1 is a photostimulable layer, 2 is a protective layer, 3 is a support,
Is a protective layer holding member, and 5 is a sealing member.

The stimulable phosphor used in the present invention refers to a stimulable phosphor (stimulated stimulus) such as optical, thermal, mechanical, chemical or electrical after irradiation with the first light or high energy radiation. It is a phosphor that exhibits stimulated emission corresponding to the dose of the first light or high-energy radiation. However, from a practical viewpoint, it is preferably a phosphor that exhibits stimulated emission by excitation light of 500 nm or more. Such stimulable phosphors include, for example, B described in JP-A-48-80487.
aSO ₄ : AX, SrSO described in JP-A-48-80489
_4: AX, JP 53-39277 and JP _{Li 2 B 4 O 7: Cu} , Ag , etc., Li ₂ O · in _{JP-A-54-47883 (B 2 O 2) x} : C and Li ₂ O ・ (B ₂
O ₂ ) _x : Cu, Ag, etc., SrS: Ce, Sm, SrS of U.S. Pat. No. 3,859,527:
Phosphors represented by Eu, Sm, La ₂ O ₂ S: Eu, Sm and (Zn, Cd) S: Mn.

Further, ZnS: C described in JP-A-55-12142
u, Pb phosphor general formula BaO · xAl ₂ O _3: barium aluminate phosphor represented by Eu, and the general formula M ^II O · xSiO _2: alkaline earth metal silicate phosphor represented by A is exemplified Can be Further, alkaline earth fluorohalide phosphors represented by the general formula (Ba _1-xy Mg _x Ca _y ) FX: eEu ^{2+ described} in JP-A-55-12143, formula is described in 12144 JP LnOX: phosphor represented by xA, the general formulas described in ^{_{JP-a-55-12145 (Ba 1-x M II}} x) FX: fluorescent represented by yA , A phosphor represented by the general formula BaFX: xCe, yA described in JP-A-55-84389, and a general formula M ^II FXxA: yLn described in JP-A-55-160078. Rare earth element-activated divalent metal fluorohalide phosphor represented by the general formula ZnS: A, CdS: A, (Zn, Cd) S: A, S: A, ZnS: A,
X and CdS: phosphors represented by A, X, and any one of the following general formulas xM ₃ (PO ₄ ) ₂ .NX ₂ : yAM ₃ (PO ₄ ) described in JP-A-59-38278. _2: phosphor represented by yA, following which are described in JP-a-59-155487 any of formulas _{nReX 3 · mAX '2: xEu} nReX 3 · mAX "2: xEu, fluorescent represented by ySm body, the following general are described in JP-a-61-72087 formula ^{M I X · aM II X '} 2 · bM III X "3: alkali halide phosphor, etc. represented by cA and the like. In particular, an alkali halide phosphor is preferable since a stimulable layer can be easily formed by a method such as vapor deposition or sputtering.

Further, alkaline earth fluorohalide phosphors and alkali halide phosphors are particularly remarkably deteriorated by moisture, and the effect of the present invention is great.

However, the stimulable phosphor used in the conversion panel of the present invention is not limited to the above-described phosphor, and is a phosphor that shows stimulable luminescence when irradiated with stimulating excitation light after being irradiated with radiation. Any fluorescent material may be used.

The photostimulable layer in the conversion panel of the present invention may be a photostimulable layer group comprising one or two or more photostimulable layers containing at least one of the photostimulable photophosphors. Further, the stimulable phosphor contained in each stimulable layer may be the same or different.

The thickness of the stimulable layer of the conversion panel is different depending on the sensitivity of the intended conversion panel to radiation, the type of stimulable phosphor, etc., but when no binder is contained, 10 μm to 1,000 μm.
, Preferably in the range of 20 μm to 800 μm, and in the case of containing a binder, in the range of 20 μm to 1,000 μm, preferably in the range of 50 μm to 500 μm.

Such a photostimulable layer is formed on the support by using a coating method, a vapor deposition method, or the like. Alternatively, the photostimulable layer may be formed on the protective layer and then laminated on the support.

Examples of the support used in the present invention include various polymer materials, glass, ceramics, and metals.

Examples of the polymer material include films of cellulose acetate film, polyester film, polyethylene terephthalate, polyamide, polyimide, triacetate, polycarbonate and the like. Examples of the metal include a metal sheet or metal plate of aluminum, iron, copper, chromium, or the like, or a metal sheet or metal plate having a coating layer of the metal oxide. Examples of the glass include chemically strengthened glass and crystallized glass. Examples of the ceramic include a sintered plate of alumina or zirconia.

The thickness of the support varies depending on the material of the support to be used and the like, but is generally 80 μm to 5 mm, and is preferably 200 μm to 3 mm from the viewpoint of easy handling.
mm. The thickness of the support is preferably that the moisture permeability in terms of moisture resistance is such a thickness equal to or less than 10.0g / m ² · 24hr, to further becomes less 5.0g / m ² · 24hr It is preferable that the thickness be as small as possible. Here, the moisture permeability was measured by a cup method (JIS Z 0208).

The surface of the support may be a smooth surface or a mat surface for the purpose of improving the adhesion to the stimulable photophosphor layer. The surface of the support may be an uneven surface, or may have a surface structure in which minute tile plates independent of each other are densely arranged.

Further, on these supports, an undercoat layer may be provided on the surface on which the photostimulable layer is provided for the purpose of improving the adhesiveness with the photostimulable layer, and if necessary, a light reflecting layer, a light absorbing layer May be provided.

As the protective layer used in the conversion panel of the present invention, a protective layer having good translucency and capable of being formed into a sheet is used. The protective layer desirably exhibits a high light transmittance in a wide wavelength range in order to efficiently transmit stimulated excitation light and stimulated emission, and the light transmittance is preferably 80% or more.

Examples of such a material include plate glass such as quartz, borosilicate glass, and chemically strengthened glass, and organic polymer compounds such as PET, drawn polypropylene, and polyvinyl chloride. Borosilicate glass has a wavelength range of 330 nm to 2.6 μm
It shows a light transmittance of 80% or more, and quartz glass shows a high light transmittance even at shorter wavelengths.

Further, it is preferable to provide an anti-reflection layer such as MgF _{2 on} the surface of the protective layer, because it has an effect of efficiently transmitting the stimulating excitation light and the stimulating light emission, and has the effect of reducing the decrease in sharpness.

The thickness of the protective layer is 25 μm to 5 mm, and preferably 100 μm to 3 mm in order to obtain good moisture proofness. The thickness of the protective layer is determined based on the moisture permeability of the protective layer.
It is preferred that the pressure be 10.0 g / m ² · 24 hr or less, preferably 5.0 g / m ² · 24 hr or less.

Further, as a material for forming the protective layer, a material having self-shape retention is preferable. Therefore, it is preferable to appropriately select a material having such a thickness as to exhibit such characteristics depending on the material of the constituent material.

In the conversion panel of the present invention, the protective layer may or may not be adhered to the photostimulable layer, but it is preferable that a low refractive index layer such as air exists between both layers. When a low refractive index layer is provided between the photostimulable layer and the protective layer, a decrease in sharpness can be prevented. Examples of such a low refractive index layer include an inert gas such as air, nitrogen, and argon, a liquid such as methyl alcohol and ethyl alcohol, and a thin film of a substance such as CaF ₂ , Na ₃ AlF ₆ , MgF ₂ , and SiO _2. Is mentioned.

The thickness of the low refractive index layer is practically 0.05 μm to 3 mm.

In the conversion panel of the present invention, after the photostimulable layer is formed on the support or the protective layer, a protective layer holding member is provided between the support and the protective layer so as to surround the photostimulable layer. The protective layer holding member used has a higher hygroscopicity than that of the stimulable photophosphor, for example, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylamide, polyglycine, polymethacrylic acid. , Polyacrylic acid, polyvinylpyrrolidone, polyvinylamine, cellulose diacetate, cellulose triacetate, nylon 4, nylon 6, nylon 12,
Water-absorbing polymers such as nylon 66, polyvinyl acetate, and polymethylallyl alcohol; and moisture-absorbing sheets in which hygroscopic properties such as silica gel and calcium carbonate are dispersed in the polymer.

Preferably the moisture permeability of the protective layer supporting member is not more than 10.0g / m ² · 24hr, when the moisture permeability is too large, preferably to the stimulable phosphor by water entering from the outside is deteriorated Absent.

The protective layer holding member can take a shape as shown in FIGS. 4 to 7, for example. That is, a part of the protective layer holding member can take various shapes made of a hygroscopic material.

The thickness of the protective layer holding member only needs to be equal to or greater than the thickness of the stimulable layer, that is, the thickness is equal to or greater than the thickness of the stimulable layer.

The case where the thickness of the protective layer holding member and that of the stimulating layer are the same is, for example, the case where the low refractive index layer is a vacuum layer. In this case, if a vacuum layer is present so as to be optically discontinuous between the photostimulable layer and the protective layer, it is sufficient as a low refractive index layer, and the two layers are in contact with each other. It may be in a state.

When the thickness of the protective layer holding member exceeds the thickness of the photostimulable layer, the thickness of the protective layer holding member can be determined in relation to the thickness of the low refractive index layer to be formed.

The width of the protective layer holding member is mainly determined by the moisture proof property (above-mentioned moisture permeability) of the contact portion between the protective layer holding member, the support and the protective layer.
It is determined in relation to the hygroscopicity of the protective layer holding member, and is preferably 1 to 30 mm. If the width of the protective layer holding member is too small, it is not preferable from the viewpoints of safety, strength, moisture resistance and moisture absorption of the protective layer holding member.
On the other hand, if it is too large, it is not preferable because the conversion panel becomes larger than necessary.

The moisture permeability of the contact portion between the protective layer holding member, the support and the protective layer is preferably 10 g / m ² · (2) hr or less.

The protective layer holding member is adhered to the support and the protective layer by a sealing member, and seals the conversion panel.

As the sealing member to be used, those having high airtightness and low moisture permeability are suitable. Specifically, epoxy resins, phenol resins, cyanoacrylate resins, vinyl acetate resins, vinyl chloride resins Organic polymer adhesives such as resin, polyurethane resin, acrylic resin, ethylene vinyl acetate resin, polyolefin resin, chloroprene rubber, nitrile rubber, and silicone adhesive,
An inorganic adhesive mainly containing alumina, silica or the like can be used. Epoxy-based resins and silicone-based resins used for encapsulating semiconductors and electronic components are preferred because of their excellent moisture resistance, and epoxy-based adhesives are particularly preferred because of their low moisture permeability.

In the conversion panel of the present invention, as shown in FIG. 3, it is preferable to further seal the outside of the protective layer holding member and the periphery of the conversion panel with the sealing member 5 ', because the moisture-proof effect is further enhanced. In particular, it is preferable that the hygroscopic protective layer holding member is not directly exposed to the outside air. In addition, this is also preferable when the moisture permeability of the protective layer holding member exceeds 10 g / m ² · 24 hr.

Sealing, using the above sealing member, or sealing by glass fusion using sealing glass such as low melting glass,
A method such as sealing with an extension of the protective layer may be mentioned, but glass fusion is particularly excellent in airtightness. In this case, the protective layer holding member may be simply bonded to the support and / or the protective layer.

The conversion panel of the present invention is used in a radiation image conversion method schematically shown in FIG.

That is, the radiation from the radiation generator 41
The light enters the conversion panel 43 through 42.

This incident radiation is absorbed by the photostimulable layer of panel 43,
The energy is accumulated, and an accumulation image of the radiation transmission image is formed.

Next, the accumulated image is excited by the stimulating light from the stimulating light source 44, and the intensity of the stimulating light is proportional to the amount of accumulated radiation energy. By performing the photoelectric conversion by the conversion device 45, reproducing the image by the image reproduction device 46, and displaying the image by the image display device 47, the radiation transmission image of the subject can be observed.

In the conversion panel according to the present invention, since the protective layer holding member has a hygroscopic property, moisture entering from the sealing portion at the periphery of the conversion panel can be effectively adsorbed and removed by the hygroscopic agent. In addition, when the conversion panel is manufactured, the moisture that has been gradually adsorbed by the photostimulable layer is reliably adsorbed and removed by the protective layer holding member, so that the deterioration of the photostimulable layer due to water is prevented, and the initial performance of the conversion panel is improved. Can be improved. In particular, regarding a conversion panel having a thick protective layer, since the penetration of moisture from the protective layer is small, the stimulable layer is hardly affected by moisture, and this effect is remarkable.

Furthermore, in the case of a conversion panel having a low refractive index layer,
The moisture remaining in the photostimulable layer moves to the protective layer holding member and is easily absorbed and removed, which is more effective.

(Examples) Next, the present invention will be described with reference to examples.

Example 1 A crystallized glass support (400 mm × 500 mm) having a thickness of 1 mm was set in a vapor deposition apparatus by an electron beam method (EB method). Next, an alkali halide phosphor (RbBr; 0.0006T1) was placed in a water-cooled crucible, and pressed to form a crucible.

Subsequently, the inside of the vapor deposition apparatus was evacuated to a vacuum degree of 5 × 10 ⁻⁶ Torr. Next, while maintaining the support at 80 to 100 ° C., the EB
Power was supplied to the gun to evaporate the stimulable phosphor.

In order to obtain the desired photostimulated layer, the deposition rate was controlled by a film thickness monitor so as to be 0 ⁴ Å / min. Also,
The electron beam scanned the stimulable phosphor surface of the crucible in a raster fashion.

The vapor deposition was terminated when the thickness of the photostimulable layer reached 300 μm.

A protective layer holding member of a 0.3 mm thick and 5 mm wide ethylene-vinyl alcohol copolymer sheet (moisture permeability 0.1 g / m ² · 24 hr) was arranged on the periphery of the stimulable layer as shown in FIG. .

Next, a protective layer of glass having a thickness of 1 mm is placed on the protective layer holding member, and a portion where the protective layer holding member contacts the support and a portion where the protective layer holding member contacts the protective layer are epoxy resin (AV-138, Then, the outer peripheral portion of the protective layer holding member was further sealed with the same epoxy resin to produce the conversion panel shown in FIG.

The evaluation of the radiation image conversion panel thus obtained was performed by leaving the conversion panel for 50 days under the conditions of 40 ° C. and 90% RH for forced deterioration, and examining the sensitivity reduction rate and the fading reduction rate. .

Further, when the photostimulable layer on the support is sealed and sealed (sealed) with a protective layer and a protective layer holding member, and the conversion panel of the present invention is manufactured, the sensitivity reduction rate before and after sealing and fading are produced. The reduction rate was examined, and the performance deterioration during the production of the conversion panel was evaluated. Before the sealing, the performance of the plate was evaluated in vacuum to remove the influence of moisture, and was used as a reference. The results are shown in Table 2.

Sensitivity reduction rate: P Irradiate 10mR of X-ray with 80KVp tube voltage, and after t seconds, stimulate excitation by semiconductor laser light (780nm, 20mW), and detect photostimulated emission emitted from photostimulated layer by photodetector The magnitude of the obtained electric signal is converted to the sensitivity S of the conversion panel.
_{(t sec)} .

5 seconds after the X-ray irradiation, the sensitivity S _{o (5 sec)} of the conversion panel before sealing, the sensitivity S _{st (5 sec)} of the conversion panel before the forced deterioration test after sealing, and the conversion panel after the forced deterioration test From the sensitivity _{S50 (5 sec)} , the sensitivity reduction rate (P) was determined by the following equation.

Decrease in sensitivity during production (Pm): Sensitivity reduction rate (Pr) due to enhanced deterioration: Fading reduction rate: Q The decay rate of the stored energy between the irradiation of the X-rays and the reading of the signal with the laser beam, that is, the fading: F, can be obtained by the following equation.

Where S _{(120 sec)} is the sensitivity 120 seconds after X-ray irradiation, S
_(5sec) represents the sensitivity after 5 seconds.

The fading reduction rate (Q) was determined from the fading F ₀ of the conversion panel before sealing, the fading F _st after sealing before the forced deterioration test, and the fading F ₅₀ after the forced deterioration test by the following formula.

Fading reduction rate during manufacturing (Qm): Fading reduction rate (Qr) due to forced deterioration: Sharpness Regarding the conversion panel before the forced deterioration test,
The MTF (modulation transfer function%) at p / mm was determined, and the sharpness of the conversion panel was evaluated.

Examples 2 to 5 The conversion panel of the present invention was manufactured in the same manner as in Example 1 except that the protective layer holding member was as shown in Table 1. The same conversion as in Example 1 was performed on the obtained conversion panel.

Example 6 The present invention was carried out in the same manner as in Example 4 except that the gap between the support and the protective layer was further sealed on the outer periphery of the protective layer holding member with an epoxy resin adhesive (AV-138, manufactured by Ciba Geigy Co., Ltd.). The conversion panel was manufactured. The same conversion as in Example 1 was performed on the obtained conversion panel.

Example 7 A conversion panel according to the present invention was manufactured in the same manner as in Example 1 except that the protective layer holding member was used in combination of two materials as shown in FIG.

The protective layer supporting member 4 ₁ crystallized glass (thickness 0.3m
m, width 5 mm), the protective layer supporting member 4 ₂ ethylene - vinyl alcohol copolymer (thickness 0.3 mm, width 5 mm). The same conversion as in Example 1 was performed on the obtained conversion panel.

Example 8 A conversion panel of the present invention was manufactured in the same manner as in Example 1 except that the stimulable layer was formed by the following method.

The method for forming the photostimulable layer is as follows. First, a coating solution was prepared by dispersing 8 parts by weight of a BaFBr: Eu phosphor having an average particle diameter of 2 μm and 1 part by weight of polyvinyl butyral (binder) using a solvent (cyclohexanone). Next, this coating solution was uniformly applied on the same support as in Example 1 placed horizontally, and left standing all day long to form a photostimulable layer. The same conversion as in Example 1 was performed on the obtained conversion panel.

Comparative Example 1 After forming a stimulable layer in the same manner as in Example 1, a glass protective layer having a thickness of 1 mm was stacked on the stimulable layer, and the peripheral portion of the stimulable layer was used in Example 1. The panel was sealed with the same epoxy resin-based adhesive to produce a conversion panel. The same conversion as in Example 1 was performed on the obtained conversion panel.

Comparative Example 2 Comparative Example 1 except that a polyethylene terephthalate film having a thickness of 10 μm was used instead of using the glass protective layer.
A conversion panel was manufactured in the same manner as described above. The same conversion as in Example 1 was performed on the obtained conversion panel.

Table 2 also shows the evaluation results of the conversion panels of Examples 2 to 8 and Comparative Examples 1 and 2.

From Table 2, the conversion panels of the present invention of Examples 1 to 8 are:
Since the protective layer holding member absorbs moisture that has entered during panel production, deterioration in sensitivity and fading characteristics during production is extremely small, and performance (initial performance) during conversion panel production is relatively improved. Also, even if the conversion panel is stored for a long time under high temperature and high humidity, the moisture that has entered the conversion panel is absorbed by the protective layer holding member, so that the initial performance can be maintained for a long time, and excellent durability can be obtained. I knew I was doing it. In particular, the durability of the conversion panel in which a moisture-proof member is disposed on the outer periphery of the moisture-absorbing protective layer holding member is further improved.

[Effect of the Invention] In the radiation image conversion panel of the present invention, since the protective layer holding member has a hygroscopic property, the radiation image conversion panel adsorbs and removes water entering from the sealing portion of the conversion panel peripheral portion. Absorbs and removes the moisture contained in the stimulable layer during the production of the conversion panel, so that the interior is kept in a dry state, and the initial performance can be improved without the stimulable layer being deteriorated by the moisture.

Therefore, according to the present invention, it is possible to provide a conversion panel that exhibits excellent characteristics even when used under severe temperature and humidity conditions or when a stimulable phosphor having poor moisture resistance is used.

[Brief description of the drawings]

1 and 3 to 7 are cross-sectional views of an embodiment of the radiation image conversion panel of the present invention, and FIG.
FIG. 8 is a sectional view taken along the line A-A ′, and FIG. 8 is an explanatory view of a radiation image conversion method using a radiation image conversion panel. DESCRIPTION OF SYMBOLS 1 ... Stimulation layer 2 ... Protective layer 3 ... Support 4 ... Protective layer holding member 4 ₁ ... Non-hygroscopic protective layer holding member 4 ₂ ... Hygroscopic protective layer holding member 5 ... Sealing member 5 '... Sealing Member 41: Radiation generating device 42: Subject 43: Radiation image conversion panel 44: Stimulation excitation light source 45: Photoelectric conversion device 46: Radiation image reproducing device 47: Radiation image display device 48: Filter

Claims (1)

(57) [Claims] 1. A radiation image conversion panel having a stimulable phosphor layer between a support and a protective layer, wherein the radiation image conversion panel surrounds the periphery of the stimulable phosphor layer, and comprises a support and the protective layer. A protective layer holding member that seals the stimulable phosphor between the protective layer holding member and a sealing member having low moisture permeability that seals the protective layer holding member from the outside; A radiation image conversion panel characterized by having a higher hygroscopicity than the stimulable phosphor.