JPS62258444A - Package body for radiation image conversion panel - Google Patents

Abstract

PURPOSE:To preserve a radiation image conversion panel contg. an accelerated luminous phosphor in a satisfactory condition for a long period of time by housing said panel into a packaging bag made of a water vapor impermeable sheet. CONSTITUTION:The two side edges of a packaging sheet 1 consisting of, for example, the two-folded water vapor impermeable sheet are sealed to form the packaging bag 3 formed with the sealed side edges 2, 2. The radiation image conversion panel P having a phosphor layer by the accelerated luminous phosphor is housed through an aperture 4 of the bag 3 into said bag 3 and the aperture 4 is sealed to form a sealed end edge 5, by which the packaging body 10 having the panel P housed therein in the hermetic state is obtd. The water vapor impermeable sheet which does not allow the permeation of water vapor or has the small permeability of the water vapor is used for the packaging sheet 1 of the bag 3. For example, the tarpaulin paper and paraffin paper specified in JIS (Japanese Industrial Standards) are used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radiation image conversion panel package, and more particularly to a radiation image conversion panel package with excellent long-term storage stability.

[Technical background]

Radiographic images such as X-ray images are often used for disease diagnosis. In order to obtain this X-ray image, the X-rays that have passed through the subject are irradiated onto a phosphor layer (fluorescent screen) to produce visible light, which is used in the same way as when taking a normal photograph. In addition to so-called radiography, in which a film using silver salt is irradiated and developed to obtain a visible image,
It is known to extract images directly from the phosphor layer without using a film coated with a silver salt.

In this method, the radiation transmitted through the object is absorbed by a phosphor, and then this phosphor is stimulated with light or thermal energy, so that the phosphor accumulates due to the absorption. There is a method of emitting the energy in the form of fluorescent light, detecting this fluorescent light, and creating an image. Specifically, for example, U.S. Pat. No. 3,859.527 and Japanese Patent Application Laid-open No. 12144/1987 disclose a radiation image conversion method using a photostimulable phosphor and using visible light or infrared rays as the photostimulation excitation light. It is shown. This method uses a radiation image conversion panel comprising a stimulable phosphor layer formed on a support. A latent image is formed by irradiating the object with energy corresponding to the radiation transmittance of each part of the object.Then, by scanning this photostimulable phosphor layer with the photostimulable excitation light, the accumulated energy of each part is emitted. This is converted into light, and an image is obtained using an optical signal based on the intensity of this light. This final image may be reproduced as a hard copy or on a cathode ray tube (CRT).

The radiation image conversion panel used in this radiation image conversion method stores radiation image information and then digitally releases the stored energy by scanning excitation light. Various processes can be performed, and radiographic images can be stored again, so they can be used repeatedly.

By the way, even when such a radiation image conversion panel is stored for a short period of time, its good characteristics deteriorate, resulting in a decrease in sensitivity or a decrease in fading characteristics in the dark, resulting in the accumulation of light before being irradiated with excitation light. It was recognized that there were problems such as a short energy retention time, and when the cause was investigated, the problem was that the stimulable phosphor of the radiation image conversion panel It has been found that the phosphor in the screen has a significantly higher hygroscopicity and readily absorbs moisture as a result.

Radiographic image conversion whose characteristics have deteriorated due to moisture absorption,
In some cases, the characteristics can be restored to some extent by drying or deoxidizing treatment, but such treatment is very labor-intensive, and in practice, it is difficult to use radiation using certain types of stimulable phosphors. In the image conversion panel, restoration of characteristics is completely impossible, and restoration of characteristics is often not achieved satisfactorily.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems of radiation image conversion panels using photostimulable phosphors, and an object of the present invention is to improve the characteristics due to moisture absorption. Even if it is a 1/1 line image conversion panel that uses photostimulable phosphors that deteriorate, it can be stored in good condition for a long period of time, and its sensitivity and dark fading characteristics will always be maintained. An object of the present invention is to provide a package in which a radiation image conversion panel can be used in an excellent condition.

[Means to solve problems]

The object of the present invention is to provide a packaging for a radiation image conversion panel, characterized in that a radiation image conversion panel containing a stimulable phosphor is housed in a packaging bag made of a water vapor impermeable sheet. accomplished by the body.

The present invention will be specifically explained below.

In the present invention, as shown in FIG. 1, a packaging bag 3 is formed by sealing the two side edges of a packaging sheet 1 made of, for example, a water vapor impermeable sheet folded in half to form sealed side edges 2.2. A radiation image conversion panel P having a phosphor layer made of a stimulable phosphor inside the packaging bag 3 from the opening 4 thereof.
is placed in the packaging bag 3, and the opening 4 is sealed to form a sealed edge 5 as shown in FIG.
shall be.

As the packaging sheet for the packaging bag used in the present invention, it is necessary to use a water vapor impermeable sheet that does not imperme water vapor or has a small i3 pass rate of water vapor. Specific examples of such sheets include JIS standard tarpaulin paper (Z1503), paraffin paper (Z1510),
Polyethylene processed paper (Z1514), vinylidene chloride processed paper (Z1515), laminated aluminum foil (Z] 52
0), moisture-proof cellophane o7'y7 (z1521), polyethylene processed cellophane (Z1526), polyethylene film for packaging (Z1702), etc., polystyrene,
Examples include polyvinyl chloride, polyester, polyethylene, polypropylene, polyvinylidene chloride, other plastic films, or composite sheets thereof.

In the present invention, it is preferable that the moisture content inside the package containing the radiation image conversion panel is 3% by weight or less, preferably 1% by weight or less of the stimulable phosphor of the radiation image conversion panel. If the amount of water inside the package is excessive, the object of the present invention cannot be fully achieved.

The configuration of the packaging bag used in the present invention (J is not particularly limited to the illustrated example, and any packaging bag that can house the radiation image conversion panel in a sealed state may be used. For example,
A structure in which two water vapor impermeable sheets are overlapped and their outer peripheries are sealed, and the packaging sheet is composed of two or more overlapping sheets, at least one of which is a water vapor impermeable sheet. Alternatively, a moisture absorbent or the like may be placed between stacked sheets.

It is necessary to seal the opening of the packaging bag, and for this purpose, it is preferable to integrally seal the two sheet portions related to the opening, as in the illustrated example. However, if it is permissible, an adhesive or the like may be used to create a structure that can be opened and closed multiple times. For example, if the packaging sheets are made double or more, and the opening can be sealed for each sheet, a sufficient sealing state can be obtained even if the packaging is sealed with adhesive.

Methods for forming the seal edges of packaging bags include mechanical binding, adhesive, heat sealing, high frequency sealing, and ultrasonic sealing. Among these, high frequency sealing or ultrasonic sealing A heat sealing method including the above is preferred.

When carrying out the present invention, in order to suppress the moisture content in the package, it is recommended to use a so-called vacuum bag form in which air is removed by applying a vacuum inside the package, or to use a dry inert bag inside the package. It is also possible to fill it with gas or to encapsulate a hygroscopic desiccant together with the radiation image conversion panel. By doing so, the effects of the present invention can be further improved.

In the present invention, the photostimulable phosphor forming the radiation image conversion panel refers to the stimulable phosphor that is irradiated with the first light or high-energy radiation, and is then irradiated with the stimulable phosphor, which is A phosphor that exhibits stimulated luminescence corresponding to the amount of initial light or high-energy radiation irradiation upon stimulation (stimulated excitation), but from a practical point of view it is preferably 50%
It is a phosphor that exhibits stimulated luminescence by stimulated excitation light of 0 nm or more.

For example, the photostimulable phosphor used in the radiation image conversion panel that is the subject of the present invention has a general formula of BaF2.a BaXz.b Me'F-c Me's
, d Me”F3: e Ln (where X is at least one of chlorine, bromine, and iodine; Me+ is at least one of lithium and sodium; MeI is at least one of helillium, calcium, and strontium; MeF is aluminum , gallium, yttrium, and lanthanum, Ln is at least one of europium, cerium, and terbium, and a, b, C, d, and e are each 0.90≦a≦1.10.0≦ b≦0.9.0≦C≦1
．． 2.0≦d≦0.03 and 10-6≦e≦0.03
This is a number that satisfies the condition. ) Alkaline earth fluorohalide phosphors can be mentioned.

In addition, the general formula is 1, nOX: x^ (where 1, n is La, Y, Gd and Lu (both are one of them, X is C1 and/or Br, A is Ce and/or
or Tb, and X represents a number satisfying 0 < x < 0.1. ) A trivalent metal oxyhalide phosphor represented by:

Furthermore, the following general formula % formula %: (However, MeI is 1.1XNa, K, Rh and Cs
at least one alkali metal selected from M
e” is Be, Mg, Ca, Sr, Ba, Zn
, Cd, , at least one selected from Cu and Ni
It is a type of divalent metal. Me” is Sc, Y,, LaXC
e, , Pr, , NdXPmXSm, Hu, Gd,
Tb, Dy.

Ho, Er, Tm, Yb, l, +1, AI, G
At least one trivalent metal selected from a and In. ×, x' and ×2 are at least one type of halogen selected from F, CI, Br and ■. A is EuX
Tb, ,Ce, Tm, ,Dy, ,Pr.

tlo,, Nd,, YhXfir,, Gd, Lu, S
m, Y,, TI, Na, Ag.

It is at least one metal selected from Cu and Mg. Also, a is a numerical value in the range of 0≦a<Q, 5, and b is O
≦b<Q, a number in the range of 5, and C is a numerical value in the range of Q<c≦0, 2. ) and the like can be mentioned.

In the case of using an alkali halide phosphor, the stimulable phosphor layer may be formed by a method such as vapor deposition or sputtering.

Among the stimulable phosphors listed above, alkaline earth fluorohalide phosphors and trivalent metal oxyhalide phosphors decompose due to moisture adsorption, resulting in decreased sensitivity; Due to the adsorption of moisture, the photoreceptor does not decompose, but phenomena such as a decrease in sensitivity or an increase in fading in the dark occur, and if this deterioration of characteristics due to moisture is not prevented, these photostimulable fluorescence The body can hardly be put to practical use as a phosphor for constructing a radiation image conversion panel. However, according to the present invention, radiation image conversion panels using these photostimulable phosphors can be sufficiently stored in a normal atmosphere without requiring any special consideration. Therefore, remarkable effects can be obtained when applied to radiation image conversion panels using these stimulable phosphors.

In the present invention, water vapor child i! The radiation image conversion panel housed in a packaging bag made of a IFJ sheet is not limited to the one made of the above-mentioned photostimulable phosphor, but when irradiated with radiation and then irradiated with photostimulable excitation light. Of course, any radiation image conversion panel may be used as long as it exhibits stimulated luminescence.

In the radiation image conversion panel, if the stimulable phosphor layer does not have self-supporting ability, a support is provided to support the stimulable phosphor layer. Such supports include various polymeric materials, glass, metals, etc., such as plastic films such as cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, and polycarbonate film, aluminum sheet, A metal sheet such as an iron sheet or a copper sheet or a metal sheet having a coating layer of the metal oxide is preferable.

The surface of these supports may be a smooth surface, but may also be a cloak surface for the purpose of improving adhesion to the stimulable phosphor layer.

Further, these supports may be provided with a subbing layer on the surface on which the photostimulable phosphor layer is provided, for the purpose of improving the adhesion with the photostimulable phosphor layer. Although the layer thickness of these supports varies depending on the material of the support used, it is generally 80 μm to 2000 μm, and preferably 80 μm to 1000 μm from the viewpoint of handling.

The radiation image conversion panel may generally be provided with a protective layer for physically or chemically protecting the stimulable phosphor layer. This protective layer may be formed by directly applying a protective layer coating liquid onto the photostimulable phosphor layer, or by applying a separately formed protective layer in advance onto the photostimulable phosphor layer. It may be provided by adhering to.

Alternatively, a radiation image conversion panel may be manufactured by a procedure of forming a stimulable phosphor layer on a separately formed protective layer. Materials for the protective layer include cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, and polytrifluorochloride. Common protective layer materials such as ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene chloride-vinyl chloride copolymer, and vinylidene chloride-acrylonitrile copolymer are used. In addition, this protective layer is formed using SiC by vapor deposition method, sputtering method, etc.
, SiO□, SiN, AlzO+, and other inorganic materials may be laminated.

The thickness of these protective layers is generally preferably about 0.1 to 100 layers.

The coating solution for the stimulable phosphor is prepared using a dispersion device such as a ball mill, sand mill, attritor, three-roll mill, high-speed impeller dispersion machine, Kady mill or ultrasonic dispersion machine.

8 laps of coating? (9) is applied onto a support using a doctor field coater, roll coater, knife coater, etc., and dried to form a stimulable phosphor layer. In some cases, the stimulable phosphor layer and the support are bonded together after drying.

In addition, stearic acid, phthalic acid, caproic acid, and lipophilic surfactants are added to the coating solution for the photostimulable phosphor layer in order to improve the dispersibility of the phosphor particles in the photostimulable phosphor layer. Dispersants such as these may be mixed. Furthermore, a plasticizer may be added to the binder if necessary. Examples of the plasticizer include phthalate esters such as diethyl phthalate and dibutyl phthalate, phosphate esters such as tricresyl phosphate and triphenyl phosphate, aliphatic dibasic acid esters such as diisodecyl succinate and dioctyl adipate, and ethyl glycolate. Examples include glycolic acid esters such as phthalyl ethyl, butyl phthalyl butyl glycolate, and the like.

Examples of solvents used to prepare photostimulable phosphor dispersions include methanol, ethanol, isopropanol, n-
Lower alcohols such as butanol, ketones such as acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, acid M
Esters of lower fatty acids such as n-butyl and lower alcohols, ethers such as dioxane, ethylene glycol monoethyl ether, and ethylene glycol monomethyl ether, aromatic compounds such as triols and quijiroles, and halogens such as methylene chloride and ethylene chloride. Examples include hydrogenated hydrocarbons.

Binders include, for example, proteins such as gelatin, polysaccharides such as dextran or gum arabic, polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethylcellulose, vinylidene chloride-vinyl chloride copolymer, polymethyl methacrylate, vinyl chloride-vinyl acetate copolymer. Binders commonly used in layer construction are used, such as polyurethane, cellulose acetate butyrate, polyvinyl alcohol, and the like. Generally, the binder is used in an amount of 0.01 to 1 part by weight per 1 part by weight 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 from the viewpoint of ease of coating, it is more preferably in the range of 0.03 to 0.2 parts by weight.

The thickness of the stimulable phosphor layer of a radiation image conversion panel varies depending on the characteristics to be obtained in the panel, the type of stimulable phosphor, the mixing ratio of the binder and the stimulable phosphor, etc. But 10 tiles~
Preferably selected from the range of 1000 μs, IO
It is more preferable to select from the range of um to 500 houses.

In addition, for the purpose of improving the sharpness of the radiation image conversion panel, white powder is dispersed in the stimulable phosphor layer of the radiation image conversion panel as disclosed in JP-A-55-146447. Also, Japanese Patent Application Publication No. 55-163500
As disclosed in the above issue, the support or protective layer on the bottom surface of the phosphor layer absorbs the photostimulable phosphor layer of the radiation image conversion panel or the incident photostimulable excitation light. It may be colored with a coloring agent such as

Furthermore, the stimulable phosphor layer may have a honeycomb structure as disclosed in JP-A-59-202100.

Alternatively, as described in Japanese Patent Application No. 59-186859, even if the photostimulable phosphor particles have a predetermined particle size distribution in the thickness direction of the photostimulable phosphor layer. good.

〔Example〕

Next, the present invention will be explained by examples.

Example 1 Patent application for 500-thick aluminum plate
The support obtained by anodizing, sealing, and heating according to the method described in No. 6914 was placed in a vapor deposition device. Next, an alkali halide stimulable phosphor (RbBr: 0.0
The evaporator was then evacuated to a vacuum of 2 x lo-6 Torr.

Next, an electric current is applied to the tungsten boat, and the alkali halide stimulable phosphor is evaporated by a resistance heating method, and the stimulable phosphor layer is deposited on the aluminum plate until the layer thickness becomes 300 mm. An exhaustible phosphor layer was formed.

Then, on the surface of the photostimulable phosphor layer, a protective layer is formed by adhering a polyester adhesive on one side of a polytrifluoroethylene chloride film with a commercially available thickness of 2 tiles to form a radiographic image. Conversion panel A was obtained.

Example 2 Ball: 8 parts by weight of F, u'' photostimulable phosphor and 1 part by weight of polyvinyl butyral resin were mixed and dispersed using 5 parts by weight of a solvent (cyclohexanone), and applied for the photostimulable phosphor layer. A liquid was prepared. Next, the coating liquid was placed horizontally to a thickness of 30 mm.
The mixture was uniformly applied onto a black polyethylene terephthalate support using a doctor blade and air-dried to form a stimulable phosphor layer having a thickness of about 25011 ITl.

Then, a polyethylene terephthalate film with a thickness of 6Iim is adhered to the surface of the stimulable phosphor layer to form a protective layer,
A radiation image conversion panel B was obtained.

Comparative tests were conducted and evaluated using the following method using a plurality of panels A and B manufactured as described above.

That is, first, Panel A and Panel B were left in a dryer for two days, and then the sensitivity of each panel to radiation was measured.

Next, a portion of each of Panel A and Panel B is sealed in a vacuum-puncture shape in a water vapor-impermeable packaging bag made of laminated aluminum foil sheets to prepare a packaged radiation image conversion panel of the present invention, and the sample is On the other hand, samples without such sealed packaging were used as comparative samples, and these samples and comparative samples were placed in a constant temperature and humidity chamber at a temperature of 40'C1 and a relative humidity of 80% for 30 minutes.
The panels were left for a day, and then the radiation sensitivity of the panels of the sample and comparative sample was measured. The value is expressed as a relative value with the first measured radiation sensitivity as the standard (100%), and the first
Shown in the table.

The radiation sensitivity is determined by applying X-rays at a tube voltage of 80 KVp to the target panel at 100°C through an aluminum stamp wafer.
After mR irradiation, He-Ne laser light (wavelength 633
This was carried out by measuring the voltage value when the stimulated luminescence emitted from the photostimulable phosphor layer was photoelectrically converted using a photomultiplier tube.

Table 1 As is clear from Table 1, even after the radiation image conversion panel package according to the present invention is stored as is for a long period of time, the characteristics of the contained radiation image conversion panel do not deteriorate. Therefore, there is no need to store it in a special environment, such as a drying room, and it can be used extremely conveniently as a radiation image conversion panel with the desired performance at all times. Alkaline earths are particularly sensitive to moisture, and when exposed to moisture, they actually lose their excellent properties.For this reason, it has been virtually impossible to put them to practical use. Stimulable phosphors such as fluorohalide phosphors, trivalent metal oxyhalide phosphors or alkali halide phosphors can now be used to form phosphor layers in radiation image conversion panels. In this respect, the present invention is particularly effective.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are explanatory perspective views of the panel package of the present invention, showing the state before and after the opening is sealed, respectively. ■...Packaging sheet 2...Seal side edge 3...Packaging bag 4...Opening 45...Seal edge 1
0...Package P...Radiation image conversion panel

Claims (2)

[Claims] (1) A radiation image conversion panel package characterized in that a radiation image conversion panel containing a stimulable phosphor is housed in a packaging bag made of a water vapor impermeable sheet. (2) Claim 1, wherein the photostimulable phosphor contains at least one of an alkaline earth fluorohalide phosphor, a trivalent metal oxyhalide phosphor, and an alkali halide phosphor. The radiation image conversion panel package described above.