JP2002131494A - Radiation image conversion panel, its cassette and radation image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image conversion panel, its cassette and a radiation image reader capable of detecting in advance the problems of degrading of radiation sensitivity caused by degradation of stimulable phosphor body and of S/N ratio due to fastening latent image regression and guaranteeing good utilization state. SOLUTION: The radiation image conversion panel has a stimulable phosphor layer and a function for judging the degradation state of the fluorescent body in the stimulable phosphor layer.

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 using a stimulable phosphor, a cassette thereof, and a radiation image reading apparatus, and more particularly to monitoring of deterioration of phosphor performance and information monitored. The present invention relates to a radiation image conversion panel having a display function, a cassette thereof, and a radiation image reading apparatus.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are widely used for diagnosis of diseases. In order to obtain this X-ray image, X-rays that have passed through the subject are irradiated on a phosphor layer (also referred to as a fluorescent screen) to generate visible light, and this visible light is used in the same manner as when a normal photograph is taken. A so-called radiograph is used in which a film using a silver salt (a silver halide photographic material) is irradiated and developed. However, in recent years, a method has been devised for directly taking out an image from the phosphor layer without using a film coated with a silver salt.

In this method, radiation transmitted through a subject is absorbed by a phosphor, and then the phosphor is excited by, for example, light or heat energy, so that the radiation energy accumulated by the phosphor is absorbed by the phosphor. Then, there is a method of detecting and imaging this fluorescence.

Specifically, for example, US Pat.
There is known a radiation image conversion method using a stimulable phosphor as described in JP-A No. 527 and JP-A-55-12144.

In this method, a radiation image conversion panel containing a stimulable phosphor is used. Radiation transmitted through a subject is applied to the stimulable phosphor layer of the radiation image conversion panel to transmit radiation of each part of the subject. By accumulating radiation energy corresponding to the density, and subsequently exciting the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light in a time series manner, the stimulable phosphor is accumulated in the stimulable phosphor. The emitted radiation energy is emitted as stimulated emission, and a signal based on the intensity of the light is photoelectrically converted, for example, to obtain an electrical signal. Technology to play as.

According to the above radiation image recording / reproducing method,
Compared with the conventional radiographic method using a combination of a radiographic film and an intensifying screen, there is an advantage that a radiographic image rich in information can be obtained with a much smaller exposure dose.

As described above, the stimulable phosphor is a phosphor that emits stimulable light when irradiated with radiation and then with excitation light. However, in practice, excitation light having a wavelength in the range of 400 to 900 nm is used. In general, phosphors exhibiting stimulated emission in the wavelength range of 300 to 500 nm are used.

The following are examples of stimulable phosphors conventionally used in radiation image conversion panels.

(1) (Ba _1-X , M ²⁺ _X ) x: yA (where M
²⁺ is at least one of Mg, Ca, Sr, Zn and Cd, X is at least one of Cl, Br and I, A is Eu, Tb, Ce, Tm, Dy, Pr, H
at least one of o, Nd, Yb, and Er;
And x is 0 ≦ x ≦ 0.6 and y is 0 ≦ y ≦ 0.2). A rare earth element-activated alkaline earth metal fluoride halide phosphor represented by a composition formula: The phosphor may include the following additives:

[0010] JP-A has been described in JP 56-74175, X ', BeX ", M 3 X''' 3 ( However,
X ', X ", and X"' are each at least one of Cl, Br and I, and M3 is a trivalent metal);

[0011] BeO, BgO, CaO, SrO, BaO, Z described in JP-A-55-160078.
nO, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO
₂ , TiO ₂ , ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ ,
Metal oxides such as Ta ₂ O ₅ and ThO ₂ ;

Zr and Sc described in JP-A-56-116777; B described in JP-A-57-23673; As described in JP-A-57-23675. Si;

M · L described in JP-A-58-206678 (where M is Li, Na, K, Rb,
And L is Sc, Y, La, Ce, Pr, or at least one alkali metal selected from the group consisting of
Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, T
m, Yb, Lu, Al, Ga, In, and at least one trivalent metal selected from the group consisting of Tl);

A calcined product of a tetrafluoroborate compound described in JP-A-59-27980;
A calcined product of a salt of a monovalent or divalent metal of hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid described in JP-A-9-27289;

NaX 'described in JP-A-59-56479 (where X' is at least one of Cl, Br and I);

[0016] JP-A-59-56480 describes
Transition of V, Cr, Mn, Fe, Co and Ni
Metal transfer; described in JP-A-59-75200
M ¹X ', M'^TwoX ", M^ThreeX '' ', A (where M¹
Is selected from the group consisting of Li, Na, K, Rb, and Cs.
At least one alkali metal,^TwoIs
At least one selected from the group consisting of Be and Mg
A divalent metal; M^ThreeAre Al, Ga, In, and T
at least one trivalent metal selected from the group consisting of
A is a metal oxide; X ', X ", and
X "" is a group consisting of F, Cl, Br and I, respectively.
At least one halogen selected from)

M ¹ X 'described in JP-A-60-101173 (where M ¹ is at least one alkali metal selected from the group consisting of Rb and Cs; X' is F, Cl, At least one halogen selected from the group consisting of Br and I);

M ² 'X' ₂ · M ² 'X " ₂ (where M ² ' is B
X 'and X "are each at least one halogen selected from the group consisting of Cl, Br and I, and X' {X ");

And LnX ″ ₃ described in JP-A-61-264084 (where Ln is Sc,
Y, La, Ce, Pr, Nd, Pm, Sm, Gd, T
at least one rare earth element selected from the group consisting of b, Dy, Ho, Er, Tm, Yb and Lu;
X "is at least one halogen selected from the group consisting of F, Cl, Br and I);

(2) M ² X ₂ .aM ² X ' ₂ : xEu ²⁺ (provided that it is described in JP-A-60-84381)
M ² is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; X and X ′
Is at least one halogen selected from the group consisting of Cl, Br and I, and X ≠ X ′; and a is 0.1 ≦ a ≦ 0.0 and x is 0 <x ≦ 0.2 A divalent europium-activated alkaline earth metal halide phosphor represented by the following composition formula:

The phosphor may contain the following additives: M ¹ X 'described in JP-A-60-166379 (where M ¹ is Rb and Cs X 'is at least one halogen selected from the group consisting of F, Cl, Br and I);

The KX as described in JP-A-60-221483 ", MgX '''2 , M 3 X""3 ( however, M ³ is Sc, Y, La, from the group consisting of Gd and Lu At least one trivalent metal selected; X ″,
X ″ ′ and X ″ ″ are at least one halogen selected from the group consisting of F, Cl, Br and I);

Oxides of SiO _2, etc. P ₂ O ₅ as described in JP 60-228593 JP; [0023] B, which are described in JP 60-228592 Laid Sho 61-1
LiX ″, NaX ″ described in US Pat.
(Where X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I);

SiO described in JP-A-61-120883; SnX " ₂ described in JP-A-61-120885 (where X" is F, Cl, B
at least one halogen selected from the group consisting of r and I);

CsX "and SnX"" ₂ described in JP-A-61-235486 (where X" and X "" are each at least selected from the group consisting of F, Cl, Br and I) A type of halogen);

And CsX ″ and Ln ³⁺ described in JP-A-61-235487 (where X ″ is F,
Ln is at least one halogen selected from the group consisting of Cl, Br and I; Ln is Sc, Y, Ce, Pr,
Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y
at least one rare earth element selected from the group consisting of b and Lu);

(3) LnOX: xA described in JP-A-55-12144 (where Ln is La,
At least one of Y, Gd, and Lu; X is C
at least one of l, Br, and I; A is at least one of Ce and Tb; and x is 0 <x
<0.1), a rare earth element-activated rare earth oxyhalide phosphor represented by a composition formula:

(4) M ³ OX: xCe described in JP-A-58-69281 (where M ³ is Pr, N
d, Pm, Sm, Eu, Tb, Dy, Ho, Er, T
at least one metal oxide selected from the group consisting of m, Yb, and Bi; X is at least one of Cl, Br, and I; and x is 0 <x <0.1). A cerium-activated trivalent metal oxyhalide phosphor represented by the formula:

(5) M ¹ X: xBi described in JP-A-62-25189 (where M ¹ is at least one alkali metal selected from the group consisting of Rb and Cs; X is At least one halogen selected from the group consisting of Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2) bismuth-activated alkali metal halide fluorescence represented by the composition formula: body;

[0030] _{^{(6) M 2 5 (PO}} 4) as described in JP 60-141783 discloses ₃ X: xEu ²⁺ (where
M ² is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is F, C
at least one halogen selected from the group consisting of l, Br and I; x is a numerical value in the range of 0 <x ≦ 0.2), and a divalent europium-activated alkaline earth metal represented by a composition formula: Halophosphate phosphor;

(7) M ² ₂ BO ₃ X: xEu ^{2 +} described in JP-A-60-157 099 (where M ² is at least one alkali selected from the group consisting of Ca, Sr and Ba) X is at least one halogen selected from the group consisting of Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2). Europium-activated alkaline earth metal haloborate phosphor;

(8) M ² ₂ (PO ₄ ) ₃ X: xEu ²⁺ described in JP-A-60-157100 (provided that
M ² is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is Cl, B
at least one halogen selected from the group consisting of r and I; x is a numerical value in the range of 0 <x ≦ 0.2) divalent europium-activated alkaline earth metal halophosphoric acid represented by the composition formula: Salt phosphor;

(9) M ² HX: xEu ²⁺ described in JP-A-60-217354 (where M ² is C
a is at least one alkaline earth metal selected from the group consisting of a, Sr and Ba; X is at least one halogen selected from the group consisting of Cl, Br and I; x is 0 <x ≦ 0.2 A divalent europium-activated alkaline earth metal hydride halide phosphor represented by the following composition formula:

[0034] (10) JP-61-21173 Patent LnX disclosed in Japanese ^{_{3 · aLn'X '3: xCe 3+}} ( However, Ln and Ln', respectively Y, La, the group consisting of Gd and Lu X and X 'are each at least one halogen selected from the group consisting of F, Cl, Br and I, and X ≠ X'; and a is 0 .1 <
a is a numerical value in a range of 10.0 and x is 0 <x ≦ 0.2
Cerium-activated rare earth composite halide phosphor represented by the composition formula:

(11) LnX ₃ .aM ¹ X ' ₃ : xCe ³⁺ described in JP-A-61-21182 (where Ln is at least selected from the group consisting of Y, La, Gd and Lu) A kind of rare earth element; M ¹ is L
i is at least one alkali metal selected from the group consisting of Na, K, Cs and Rb; X and X 'are each at least one halogen selected from the group consisting of Cl, Br and I; 0 <a ≦ 1
A cerium-activated rare earth composite halide-based phosphor represented by a composition formula of the following formula: 0.0 is a numerical value in the range of 0.0, and x is a numerical value in the range of 0 <x ≦ 0.2;

(12) LnPO ₄ .aLnX ₃ : xCe ³⁺ described in JP-A-61-40390 (where Ln is at least one rare earth element selected from the group consisting of Y, La, Gd and Lu) X is F, C
a is at least one halogen selected from the group consisting of l, Br and I; and a is 0.1 ≦ a ≦ 10.0
Wherein x is a number in the range of 0 <x ≦ 0.2), a cerium-activated rare earth halophosphate phosphor represented by a composition formula;

(13) CsX: aRbX ': xEu ²⁺ described in JP-A-61-236888 (wherein X and X' are each at least one member selected from the group consisting of Cl, Br and I) Is a halogen;
And a is a numerical value in the range of 0 <a ≦ 10.0, and x is a numerical value in the range of 0 <x ≦ 0.2.) A divalent europium-activated cesium rubidium halide represented by a composition formula: Phosphor; and

(14) M ² X ₂ .aM ¹ X ': xEu ²⁺ described in JP-A-61-236890 (where M ² is selected from the group consisting of Ba, Sr and Ca) M1 is at least one alkali metal selected from the group consisting of Li, Rb and Cs; X and X 'are each at least one selected from the group consisting of Cl, Br and I A is 0.1 ≦ a ≦ 20.
Is a numerical value in the range of 0, and x is a numerical value in the range of 0 <x ≦ 0.2).

Among the stimulable phosphors described above, iodine-containing divalent europium-activated alkaline earth metal fluorohalide-based phosphors, iodine-containing divalent europium-activated alkaline earth metal halides The iodine-containing rare earth element-activated rare earth oxyhalide-based phosphor and the iodine-containing bismuth-activated alkali metal halide-based phosphor exhibit high luminance stimulable luminescence.

A radiation image conversion panel using these stimulable phosphors emits stored energy by scanning with excitation light after accumulating radiation image information, so that the radiation image can be accumulated again after scanning. It can be used repeatedly. In other words, the conventional radiographic method consumes radiographic film for each photographing, whereas the radiographic image conversion method uses the radiographic image conversion panel repeatedly, which is advantageous in terms of resource conservation and economic efficiency. It is.

Therefore, it is desirable to provide the radiation image conversion panel with a performance that can withstand long-term use without deteriorating the image quality of the obtained radiation image.

However, the radiation image conversion panel has scratches due to repeated use, stains,
In addition, degradation due to ultraviolet rays, natural radiation, etc., and to a greater or lesser degree, stimulable phosphors exhibit a deterioration in image performance due to various external environments surrounding the radiation image conversion panel such as showing a moisture absorption phenomenon. Occurs. To deal with them,
As a protective function of the radiation image conversion panel, it is common to provide a protective layer on the phosphor layer to maintain the performance of the phosphor.

Specifically, when the stimulable phosphor is left under high temperature and high humidity for a long time or exposed to a high energy ray, it may absorb or decompose. Function deteriorates. Further, when the function of the protective layer is impaired due to scratches or the like, the image quality of the radiation image deteriorates. Also, since the latent image of a radiation image recorded on a stimulable phosphor generally regresses with the elapse of time after irradiation, the intensity of a reproduced radiation image signal varies from irradiation to reading by excitation light. The longer the time, the smaller the size. However, when the stimulable phosphor deteriorates, the speed of the latent image retreat increases. Therefore, when a radiation image conversion panel having a stimulable phosphor that has absorbed moisture is used, the S / N ratio of a reproduction signal at the time of reading a radiation image decreases.

Conventionally, in order to prevent the above-mentioned deterioration phenomenon due to moisture absorption of the stimulable phosphor, the stimulable phosphor layer is reached by covering the stimulable phosphor layer with a moisture-proof protective layer having low moisture permeability. A method of reducing moisture has been adopted. As the moisture-proof protective layer, a polyethylene terephthalate (PET) film, a polyethylene terephthalate film, a polyethylene terephthalate (PET) film, a polyethylene terephthalate film, or a vapor-deposited film obtained by vapor-depositing a thin film of a metal oxide, silicon nitride, or the like is used.

As described above, the protective layer is designed so as to minimize the deterioration of image quality while having a protective function against an external environment such as a moisture proof property, a high energy ray cutting function, and a scratch proof property. However, a universal protective layer has not been designed for all external environments, and as a result of repeated use over many years, the phosphor function gradually decreases due to moisture permeation and the like. It is further accelerated by scratching the layer. If the S / N ratio is severely deteriorated, such as the problem of deterioration of radiation sensitivity due to the deterioration over time or the rapid regression of the latent image, it is fatal for a radiation image conversion panel used for disease diagnosis. It becomes a defect.

[0046]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of deterioration of radiation sensitivity due to deterioration of stimulable phosphor and reduction of S / N ratio such as rapid regression of a latent image. It is an object of the present invention to provide a radiation image conversion panel, a cassette thereof, and a radiation image reading apparatus which can be detected in advance and ensure that the panel is used in a good condition.

[0047]

The above objects of the present invention have been attained by the following constitutions. 1. A radiation image conversion panel having a stimulable phosphor layer, the radiation image conversion panel having a function of determining a deterioration state of the phosphor of the stimulable phosphor layer.

2. A phosphor image sheet having a stimulable phosphor layer on a support, and a radiation image conversion panel having a protective layer provided so as to cover the phosphor surface of the phosphor sheet, wherein the deterioration state of the phosphor is determined. A radiation image conversion panel provided with a detection function.

3. A phosphor image sheet having a stimulable phosphor layer on a support, and a radiation image conversion panel having a protective layer provided so as to cover the phosphor surface of the phosphor sheet, wherein the deterioration state of the phosphor is determined. A radiation image conversion panel having a function of detecting and displaying the detected radiation image.

4. Radiation image conversion panel image using a phosphor sheet having a stimulable phosphor layer on a support and a radiation image conversion panel having a protective layer provided so as to cover the phosphor surface of the phosphor sheet A cassette for a radiation image conversion panel, comprising a function of detecting a deterioration state of a phosphor.

5. Radiation image conversion panel image using a phosphor sheet having a stimulable phosphor layer on a support and a radiation image conversion panel having a protective layer provided so as to cover the phosphor surface of the phosphor sheet A cassette for a radiation image conversion panel, comprising a function of detecting a deterioration state of a phosphor and displaying the deterioration state.

6. A radiation image reading apparatus is used in which a phosphor sheet having a stimulable phosphor layer on a support and a radiation image conversion panel having a protective layer provided so as to cover the phosphor surface of the phosphor sheet are used. A radiation image reading apparatus provided with a function of detecting a deterioration state of the phosphor.

7. A radiation image reading apparatus is used in which a phosphor sheet having a stimulable phosphor layer on a support and a radiation image conversion panel having a protective layer provided so as to cover the phosphor surface of the phosphor sheet are used. A radiation image reading apparatus provided with a function of detecting a deterioration state of the phosphor and displaying the deterioration state.

8. 3. The radiation image conversion panel according to the above item 1 or 2, wherein the amount of water in the phosphor layer is detected.

9. 9. The radiation image conversion panel according to the above 1, 2 or 8, wherein the amount of oxygen in the phosphor layer is detected.

10. 10. The radiation image conversion panel according to the above item 1, 2, 8 or 9, wherein the electric conductivity in the phosphor layer is detected.

[0057]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail. The protective layer used in the present invention may be composed of a protective film. This protective film can be optimally moisture-proof by laminating a plurality of resin films or vapor-deposited films on which metal oxides are vapor-deposited, according to the required moisture-proof properties. It is preferably at least 50 g / m ² · day or less in consideration of the moisture absorption deterioration of the phosphor. As a method for laminating the resin film, any generally known method may be used. Further, in this case, by providing the excitation light absorbing layer between the laminated resin films, the excitation light absorbing layer is protected from physical impact and chemical deterioration, and stable plate performance can be maintained for a long time. The excitation light absorbing layer may be provided at a plurality of locations, or an adhesive layer for lamination may contain a coloring agent to form an excitation light absorbing layer. Further, the excitation light absorbing layer may be constituted by adding a coloring agent to the protective film itself.

Any known method may be used for sealing the phosphor plate with the protective film, but the outermost resin layer on the side of the moisture-proof protective film that is in contact with the phosphor sheet is made of a resin having a heat-fusing property. By forming a film, the moisture-proof protective film can be fused and the sealing work of the phosphor sheet is made more efficient.

Preferably, a moisture-proof protective film is arranged above and below the phosphor sheet, and the upper and lower moisture-proof protective films are fused in a region where the peripheral edge is outside the peripheral edge of the phosphor sheet. With this structure, it is possible to prevent moisture from entering from the outer peripheral portion of the phosphor sheet. Furthermore, the infiltration of moisture can be reduced more reliably by forming a laminated moisture-proof film obtained by laminating one or more aluminum films as the moisture-proof protective film on the support surface side (see FIG. 1). This sealing method is also easy in terms of work.

In this case, the surface of the outermost layer of the moisture-proof protective film which is in contact with the phosphor surface and which has the heat-fusible resin layer and the phosphor layer may or may not be adhered.

The state of non-adhesion means that the surface of the phosphor layer and the moisture-proof protective film are optically and mechanically almost completely in contact with the surface of the phosphor layer, even though they are in point contact with each other microscopically. The protective film can be handled as a discontinuous body.

The term "heat-fusible film" as used herein refers to a resin film which can be fused with a generally used impulse sealer, such as ethylene-vinyl acetate copolymer (EVA), polypropylene (PP) film, polyethylene ( PE) film and the like, but are not limited thereto.

It is assumed that the protective film of the radiation image conversion panel has a very high optical transparency. As such a highly transparent protective film material, various plastic films having a haze value in the range of 2 to 3% are commercially available.

As the support used in the radiation image conversion panel of the present invention, various polymer materials are used.
Especially on the handling as an information recording material, those that can be processed into a flexible sheet or web are suitable, and in this regard, cellulose acetate film, polyester film, polyethylene terephthalate film, polyethylene naphthalate film, polyamide film, Plastic films such as polyimide films, triacetate films, and polycarbonate films are preferred.

The thickness of the support varies depending on the material of the support to be used and the like.
00 μm, and preferably 80 μm from the viewpoint of handling.
μm to 500 μm.

The surface of the support may be a smooth surface or a mat surface for the purpose of improving the adhesion to the stimulable phosphor layer.

Further, these supports may be provided with an undercoat layer on the surface on which the stimulable phosphor layer is provided for the purpose of improving the adhesion to the stimulable phosphor layer.

Examples of the binder (also referred to as a binder) used for the stimulable phosphor layer in the present invention include proteins such as gelatin, polysaccharides such as dextran, and naturally occurring polymers such as gum arabic. Molecular substances; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, vinylidene chloride-vinyl chloride copolymer, polyalkyl (meth) acrylate,
Examples of the binder include synthetic polymer substances such as vinyl chloride / vinyl acetate copolymer, polyurethane, cellulose acetate butyrate, polyvinyl alcohol, and linear polyester.

Particularly preferred among such binders are nitrocellulose, linear polyester, polyalkyl (meth) acrylate, a mixture of nitrocellulose and linear polyester, nitrocellulose and polyalkyl (meth) acrylate. And a mixture of polyurethane and polyvinyl butyral. In addition, these binders may be cross-linked by a cross-linking agent.

The stimulable phosphor layer can be formed on the undercoat layer by the following method, for example. First, a stimulable phosphor and a binder are added to an appropriate solvent, and these are sufficiently mixed to prepare a coating liquid in which phosphor particles and particles of the compound are uniformly dispersed in a binder solution.

In general, the binder is used in an amount of 0.01 to 1 part by mass per 1 part by mass of the stimulable phosphor. However, from the viewpoint of the sensitivity and sharpness of the obtained radiation image conversion panel, it is preferable that the amount of the binder is small, and the range of 0.03 to 0.2 part by mass is more preferable in consideration of the ease of application.

Examples of the solvent used for preparing the coating solution for the stimulable phosphor layer include lower alcohols such as methanol, ethanol, isopropanol and n-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.
Ketones such as cyclohexanone, esters of lower fatty acids such as methyl acetate, ethyl acetate and n-butyl acetate with lower alcohols, dioxane, ethers such as ethylene glycol monoethyl ether and ethylene glycol monomethyl ether, aromatic compounds such as triols and xylol And halogenated hydrocarbons such as methylene chloride and ethylene chloride, and mixtures thereof.

The coating solution contains a dispersant for improving the dispersibility of the phosphor in the coating solution, and a binder between the binder and the phosphor in the stimulable phosphor layer after formation. Various additives such as a plasticizer for improving the bonding strength may be mixed. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, and lipophilic surfactants. Examples of the plasticizer include phosphoric esters such as triphenyl phosphate, tricresyl phosphate, and diphenyl phosphate; phthalic esters such as diethyl phthalate and dimethoxyethyl phthalate; ethylphthalylethyl glycolate and butylphthalylbutyl glycolate; Glycolic acid esters of
And polyester of polyethylene glycol and aliphatic dibasic acid, such as polyester of triethylene glycol and adipic acid, polyester of diethylene glycol and succinic acid, etc. can be mentioned.

The coating solution for the stimulable phosphor layer is prepared using a dispersing device such as a ball mill, a sand mill, an attritor, a three-roll mill, a high-speed impeller disperser, a Kady mill, and an ultrasonic disperser. The prepared coating solution is coated on a support using a coating solution such as a doctor blade, a roll coater, or a knife coater, and dried to form a stimulable phosphor layer.

Next, the formed coating film is dried by gradually heating to complete the formation of the stimulable phosphor layer on the undercoat layer.

The thickness of the stimulable phosphor layer of the radiation image conversion panel of the present invention depends on the characteristics of the intended radiation image conversion panel, the type of the stimulable phosphor, and the mixing ratio between the binder and the stimulable phosphor. Although it depends on the like, it is preferably selected from the range of 10 μm to 1000 μm, more preferably from the range of 10 μm to 500 μm.

A phosphor sheet having a phosphor layer coated on a support is cut into a predetermined size. Any method can be used for cutting, but it is desirable to use a cosmetic cutting machine, a punching machine, or the like in terms of workability and accuracy.

Any known method can be used to seal the phosphor sheet cut to a predetermined size with the moisture-proof protective film. For example, the phosphor sheet is sandwiched between the upper and lower moisture-proof protective films. And a laminating method in which the peripheral edge portion is heated and fused by an impulse sealer, or a pressure is applied between two heated rollers to heat.

In the method of heat-sealing with the impulse sealer, the heat-sealing under a reduced pressure environment means that the phosphor sheet is prevented from being displaced in the moisture-proof protective film and the moisture in the air is eliminated. More preferred.

[0080]

The present invention will now be illustrated by way of examples. Example 1 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluoroiodide, a BaI ₂ aqueous solution (3.6 mol) was used.
/ L) 2780 ml and EuI ₃ aqueous solution (0.2 mol /
L) 27 ml were placed in the reactor. The reaction mother liquor in the reactor was kept at 83 ° C. while stirring. 322 ml of an aqueous solution of ammonium fluoride (8 mol / L) was injected into the reaction mother liquor using a roller pump to generate a precipitate. After completion of the injection, the temperature and the stirring were continued for 2 hours to ripen the precipitate. Next, the precipitate was separated by filtration, washed with ethanol, and dried under vacuum to obtain europium-activated barium fluoroiodide crystals. In order to prevent a change in particle shape due to sintering during firing and a change in particle size distribution due to inter-particle fusion, 0.2% by mass of ultrafine alumina powder is added, and the mixture is sufficiently stirred with a mixer. Ultrafine alumina powder was uniformly adhered to the surface. This was filled in a quartz boat and calcined at 850 ° C. for 2 hours in a hydrogen gas atmosphere using a tube furnace to obtain europium-activated barium fluoroiodide phosphor particles. Next, particles having an average particle diameter of 7 μm were obtained by classifying the phosphor particles.

As the phosphor layer forming material, 427 g of the europium-activated barium fluoroiodide phosphor obtained above, 15.8 g of polyurethane resin (Desmolac 4125, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and bisphenol A type epoxy resin 0 g of methyl ethyl ketone-toluene (1:
1) The mixture was added to a mixed solvent and dispersed by a propeller mixer to prepare a coating solution having a viscosity of 25 to 30 Pa · s. This coating solution was applied on a 100-μm-thick black PET support using a doctor blade, and then dried at 100 ° C. for 15 minutes to form a 270-μm-thick phosphor layer.

(Preparation of Protective Film) The protective film on the phosphor surface side of the phosphor sheet had the structure shown in (A) below. (A) VMPET12 // VMPET12 // PET
12 // Sealant Film PET: Polyethylene Terephthalate Sealant Film: CPP (Casting Polypropylene) or LLDPE (Low Density Linear Polyethylene) Used as a Heat-Fusing Film VMPET: Alumina-Deposited PET (Commercial Product: Toyo Metallizing) The number behind each resin film is the film thickness (μ
m). The above “//” means that the adhesive layer is a dry lamination adhesive layer (the thickness of the adhesive layer is 2.5 μm). The adhesive used for dry lamination is a two-component reaction type urethane-based adhesive.

By adding an organic blue colorant (Zabon Fast Blue 3G, manufactured by Hoechst) preliminarily dispersed and dissolved in methyl ethyl ketone to the adhesive solution used at this time, the entire adhesive layer absorbs excitation light. Layers.
The light transmittance of the excitation light absorbing layer was adjusted by adjusting the amount of addition at this time.

Here, the light transmittance of the excitation light absorbing layer means the light transmittance at the light wavelength of the He—Ne laser beam (633 nm) which is different from the light transmission of the protective film only in the absence of the excitation light absorbing layer. The value was compared with the ratio. At the same time, the haze ratio was adjusted by changing the type of the sealant film, and laminated protective films having various haze ratios were produced.

The protective film on the support surface side of the phosphor sheet was a dry laminate film having a structure of sealant film / aluminum foil film 9 μm / polyethylene terephthalate (PET) 188 μm. In this case, the thickness of the adhesive layer was 1.5 μm, and a two-component reaction type urethane adhesive was used.

(Sealing of Phosphor Sheet)
Cut into a square of 0 cm x 20 cm, using a laminated protective film having the above various haze and excitation light absorbing layers,
The periphery was sealed by fusing under reduced pressure using an impulse sealer.

FIGS. 1 and 2 show sectional views of a radiation image conversion panel of the present invention having the same configuration as that used in the above embodiment.
In the figure, 11 is a phosphor layer, 12 is a support, 13 is a protective layer,
Reference numeral 14 denotes a phosphor monitor sensor, and 19 denotes a tray plate. For the tray plate 19, a phosphor sheet provided with the protective layer is adhered to a flat plate made of magnesium metal via a support having a tape (film) above and below a lead foil. What formed the panel was used.

The fusion was performed so that the distance from the fusion portion to the peripheral edge of the phosphor sheet was 1 mm. The heater of the impulse sealer used for fusion had a width of 8 mm.

The present invention provides a function of displaying the state of deterioration of the phosphor in the protective layer film, the phosphor layer, or separately, and uses a dye or the like that reacts to the amount of moisture, oxygen, or the like to change the state of the phosphor. Display on the monitor. Specifically, any of the following configurations may be used.

1) It has a sensor 14 that can monitor the deterioration state of the phosphor constituting the phosphor layer, inside the protective layer film, or separately. When the sensor 14 also has a function of indicating a detection result, it is preferable to provide a phosphor monitor window on each of the panel 19 and the support 12 so that the sensor can be seen through (FIG. 3).

2) The sensor 14 is provided outside the phosphor image area. That is, the sensor 14 is provided outside the image reading area 18 of the radiation image conversion panel 17 in FIG.

3) The sensor 14 is provided in the phosphor image area. That is, the sensor 14 (shown by a broken line) is provided inside the image reading area 18 of the radiation image conversion panel 17 shown in FIG.

4) The sensor 14 is provided on the back side of the phosphor layer. The sensor 14 may be on the support 12 (see FIG. 1) or may be embedded (see FIG. 2).

5) The deterioration result by the sensor 14 as a monitor is displayed on the plate surface.

6) The cassette 16 can be identified from outside. Specifically, as shown in FIG. 4, a see-through window 20 is also provided on the back side of the cassette 16 for the radiation image conversion panel. Alternatively, as shown in FIG. 6, a display unit 21 for displaying a detection result is provided in the radiation image reading apparatus. That is, the display unit 21 is preferably provided for each cassette mounting unit and can be monitored for each mounting cassette, and may be displayed on a CRT screen or the like, or may be displayed by a lamp or the like.

7) The sensor 14 may have a display function.

8) The sensor 14 may be any sensor as long as it monitors the amount of water, the amount of oxygen, the conductivity (the amount of ionization of the phosphor element), and the like.

[0098] Moisture sensor: A sensor utilizing the change in the degree of color development of the phosphor layer with cobalt chloride or the like (for example, a change in color from blue to red due to moisture absorption). Further, as the moisture sensor, any of publicly known and public ones including the following can be adopted. a. A water sensor in the form of a piece of paper made by impregnating filter paper with an aqueous solution of cobalt chloride and then drying: changes to blue when dry and red when absorbed. b. A tablet-shaped moisture sensor made by impregnating an aqueous solution of cobalt chloride into a silicon oxide powder formed into a tablet and then drying: The color changes to blue when dry and red when moisture is absorbed. c. A paint-like moisture sensor marked on the phosphor surface using a paint made of a moisture-sensitive decolorizable dye: changes to colorless when dry and yellow when absorbed. d. Other examples include a paint-like moisture sensor that is marked on the phosphor surface using a moisture-coloring ink.

Oxygen sensor: an oxygen sensor that uses the change in the degree of color development of the phosphor layer with methylene blue or the like (for example, the color changes from red to blue by oxygen). Also,
As the oxygen sensor, any known and used ones can be employed. a. An oxygen sensor in the form of a piece of paper made by soaking a methylene blue aqueous solution into a filter paper and then drying: changes to blue when deoxygenated and white when oxygen is permeated. b. A methylene blue aqueous solution is impregnated into a tablet formed from silicon oxide powder, and then dried. The tablet-shaped deterioration monitor is changed to blue when deoxidized and white when deoxygenated. c. Oxygen-sensitive tablet oxygen sensor [Ageless Eye (Mitsubishi Gas Chemical Co., Ltd., trade name)]: Changes to red when deoxidized and blue when permeated with oxygen. d. Oxygen-sensitive paint-like indicator ink (manufactured by Toyo Ink Co., Ltd.): Changes to red when deoxygenated and blue when oxygen is transmitted. e. Other examples include iron oxide powder that generates heat due to the presence of oxygen.

Electric conductivity (ionization sensor): A sensor utilizing a change in electric conductivity in a phosphor layer is exemplified. For example, a conductive ink or a metal foil is provided on the phosphor layer surface at a predetermined interval, and the resistance value between the conductive ink and the metal foil is detected. For example, a configuration in which color development can be visually observed, or a configuration in which a change in conductivity is detected as an electrical signal and displayed on a panel or displayed on a monitor such as an acoustic display such as a buzzer) can be used. The detection information may be put on a radio wave transmitting chip for plate ID recognition and sent to the radiation image conversion panel image reading device.

9) As described above, the state of the phosphor is monitored and displayed using colors, light, electric signals, sound and the like.

[0102]

According to the present invention, the problem of deterioration of the radiation sensitivity due to the deterioration of the stimulable phosphor and the problem of the decrease of the S / N ratio such as the rapid regression of the latent image are detected in advance. It is possible to provide a radiation image conversion panel, a cassette thereof, and a radiation image reading apparatus which can ensure that the panel is used in a good condition.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a radiation image conversion panel of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the radiation image conversion panel of the present invention.

FIG. 3 is a schematic sectional view showing another embodiment of the radiation image conversion panel of the present invention.

FIG. 4 is a schematic sectional view showing another embodiment of the radiation image conversion panel of the present invention.

FIG. 5 is a plan view of a radiation image conversion panel illustrating a position of a phosphor sensor;

FIG. 6 is a schematic perspective view showing an example of a radiation image reading device.

[Explanation of symbols]

 Reference Signs List 11 phosphor layer 12 support 13 protective layer 14 sensor for phosphor monitor 15 phosphor monitor window 16 cassette for radiation image conversion panel 17 radiation image conversion panel 18 image reading area 19 tray plate 20 see-through window 21 display unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/04 H04N 1/04 E (72) Inventor Tomoko Saito 1st Sakuracho, Hino-shi, Tokyo Konica Corporation F term (reference) 2G083 AA03 BB02 CC01 CC09 CC10 DD11 DD16 EE10 2H013 AC01 BA02 5B047 AA17 BC14 5C072 AA01 NA02 VA01

Claims (10)

[Claims] 1. A radiation image conversion panel having a stimulable phosphor layer, the radiation image conversion panel having a function of determining a deterioration state of a phosphor of the stimulable phosphor layer. 2. A radiation image conversion panel comprising: a phosphor sheet having a stimulable phosphor layer on a support; and a protective layer provided so as to cover the phosphor surface of the phosphor sheet. A radiation image conversion panel having a function of detecting a state of deterioration of a body. 3. A radiation image conversion panel comprising: a phosphor sheet having a stimulable phosphor layer on a support; and a protective layer provided to cover the phosphor surface of the phosphor sheet. A radiation image conversion panel having a function of detecting a deterioration state of a body and displaying the detected state. 4. A radiation image conversion panel having a phosphor sheet having a stimulable phosphor layer on a support and a protective layer provided so as to cover the phosphor surface of the phosphor sheet is used. A cassette for a radiation image conversion panel, wherein the cassette for a radiation image conversion panel is provided with a function of detecting a deterioration state of a phosphor. 5. A radiation image conversion panel having a phosphor sheet having a stimulable phosphor layer on a support and a protective layer provided so as to cover the phosphor surface of the phosphor sheet is used. A cassette for a radiation image conversion panel, wherein the cassette has a function of detecting a deterioration state of a phosphor and displaying the deterioration state. 6. A radiation image conversion panel having a phosphor sheet having a stimulable phosphor layer on a support and a protective layer provided so as to cover the phosphor surface of the phosphor sheet is used. What is claimed is: 1. A radiation image reading apparatus, comprising: a function of detecting a deterioration state of a phosphor. 7. A radiation image conversion panel having a phosphor sheet having a stimulable phosphor layer on a support and a protective layer provided so as to cover the phosphor surface of the phosphor sheet is used. What is claimed is: 1. A radiation image reading apparatus, comprising: a function of detecting a deterioration state of a phosphor and displaying the deterioration state. 8. The radiation image conversion panel according to claim 1, wherein the amount of water in the phosphor layer is detected. 9. The radiation image conversion panel according to claim 1, wherein the amount of oxygen in the phosphor layer is detected. 10. The radiation image conversion panel according to claim 1, wherein the conductivity in the phosphor layer is detected.