JPH0212100A - Radiograph transforming panel - Google Patents

Abstract

PURPOSE:To improve both sensitivity and clearness and, at the same time, to uniformize the thicknesses of a light intercepting and light scattering layers by successively providing the light intercepting layer and/or light scattering layer and phosphorescent phosphor layer on a supporting body. CONSTITUTION:A transforming panel is constituted by successively providing a light intercepting layer 2 and/or light scattering layer 3 and a stimulable phosphor layer 4 on a supporting body 1. The layer 2 is formed by applying ceramic powder. It is also possible to constitute both of the layers 2 and 3 of ceramic powder. Since the layer 2 is provided for preventing incidence of the exciting light into the supporting body 1, scattering of the exciting light inside the body 1 can be eliminated and the clearness is improved. When the layer 2 is constituted of the ceramic powder in such way, the layer 2 can be formed to a stable layer and cannot be removed, since the layer 2 can be formed in a thermodynamically equilibrium state against the body 1. Moreover, since the layer is formed by utilizing an applying method, the thickness can be made uniform.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a radiation image conversion panel having a stimulable phosphor layer, and more particularly, to a radiation image conversion panel comprising a stimulable phosphor layer. The present invention relates to a radiation image conversion panel that has excellent radiation sensitivity and image sharpness because it has a scattering layer.

(Prior Art) Radiographic images such as X-ray images are widely used for disease diagnosis.

In order to obtain this X-ray image, an X-ray image conversion method has been devised in which an image is directly extracted from a phosphor layer instead of a silver halide photosensitive material.

In this method, radiation (generally X-rays) that has passed through the object is absorbed by a phosphor, and then this phosphor is excited by light or thermal energy, so that the phosphor accumulates due to the absorption of the radiation. This is a method in which radiation energy is emitted as fluorescence, and this fluorescence is detected and imaged.

Specifically, for example, U.S. Pat. Disclosed.

This method uses a radiation image conversion panel in which a stimulable phosphor layer is formed on a support, and the radiation transmitted through the subject is applied to the stimulable phosphor layer of this conversion panel to adjust the radiation transparency of each part of the subject. The radiation energy is accumulated to form a latent image, and then this photostimulation layer is scanned with photostimulation excitation light to radiate the accumulated radiation energy in each part and convert it into light. Images are obtained using optical signals depending on the intensity.

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

Now, the radiation image conversion panel having a stimulable phosphor layer used in this radiation image conversion method has a radiation absorption rate and a light conversion rate (including both Not only does it have a high radiation sensitivity (hereinafter referred to as "radiation sensitivity"), but it also has good image graininess.
Moreover, high sharpness is required.

However, in general, a radiation image conversion panel having a stimulable phosphor layer is prepared by coating a dispersion containing a granular stimulable phosphor with a particle size of about 1 to 30 Jffi and an organic binder on a support or a protective layer. Since it is created by drying, the packing density of the stimulable phosphor is low (50% filling rate), and the radiation sensitivity is sufficiently high (
To achieve this, it was necessary to increase the thickness of the stimulable phosphor layer.

On the other hand, in the radiation image conversion method, the image sharpness tends to be higher as the thickness of the stimulable phosphor layer of the radiation image conversion panel becomes thinner. It was necessary to make the stimulable phosphor layer thinner.

In addition, the graininess of the image in the radiation image conversion method is caused by local fluctuations in the number of radiation quanta (quantum mottles) or structural disturbances in the stimulable phosphor layer of the radiation image conversion panel.
As the thickness of the stimulable phosphor layer becomes thinner, the number of radiation quanta absorbed by the stimulable phosphor layer decreases, increasing the quantum mottle and causing structural disorder. becomes obvious and structural mottles increase, resulting in a decrease in image quality. Therefore, in order to improve the graininess of images, the stimulable phosphor layer needs to be thick. That is, as mentioned above, in the conventional radiation image conversion panel, the sensitivity to radiation, the graininess of the image, and the sharpness of the image exhibit completely opposite trends with respect to the layer thickness of the stimulable phosphor layer. The radiographic image information panels have been made with some trade-off between sensitivity to radiation, graininess, and sharpness.

In other words, in conventional radiation image conversion panels, the sharpness of the image rapidly decreases as the thickness of the stimulable phosphor layer increases due to the large scattering and diffusion of the stimulable excitation light by the stimulable phosphor particles. Even if there are bad points in both degrees, it is difficult to find good points in both degrees.

By the way, it is well known that the sharpness of images in conventional radiography is determined by the spread of instantaneous light emission (light emission during radiation irradiation) of the phosphor in the fluorescent screen. The sharpness of the image in the radiation image conversion method using a stimulable phosphor is not determined by the spread of stimulated luminescence of the stimulable phosphor in the radiation image conversion panel; rather than being determined by the spread of the emission of
It depends on the spread of the stimulated excitation light within the Pael.

This is because, in this radiation image conversion method, the radiation image information stored in the radiation image conversion panel is retrieved in a time-series manner. Preferably, it is recorded as the output from a certain pixel (xi, yi) on the panel that is fully illuminated and irradiated with the stimulated excitation light at that time, but if the stimulated excitation light is scattered within the panel, etc. If it spreads and also excites the stimulable phosphor that exists outside the irradiated pixel (xi, yi), the output from the pixel (xi, yil) will be recorded as the output from a wider area than that pixel. Therefore, the stimulated luminescence due to the stimulated excitation light irradiated to a certain time (til)
) If only the light is emitted from the pixel fxi, yi) on the panel that was truly irradiated with the stimulated excitation light, the sharpness of the image obtained will be affected no matter how wide the emitted light is. There is no.

Under these circumstances, several methods have been attempted to improve the above-mentioned drawbacks of radiation image conversion panels having a stimulable phosphor layer formed by dispersing a stimulable phosphor in a binder.

For example, JP-A-56-11393 discloses a method of providing a metal light reflecting layer at the interface of one layer of a stimulable phosphor layer formed by dispersing a stimulable phosphor in a binder. According to this method, by changing the portion of the stimulable phosphor layer that enters inside from the interface on the incident side of the stimulable excitation light into a metal light reflecting layer, the stimulable phosphor layer The layer thickness of the stimulable phosphor layer can be made thinner, thereby making it possible to suppress the spread of the stimulable excitation light within the stimulable phosphor layer, thereby obtaining a highly sharp radiation image.

However, although this method can suppress the spread (scattering) of the stimulable excitation light within the layer by reducing the thickness of the stimulable phosphor layer,
The stimulated excitation light that reaches the metal light reflection layer while being scattered within the layer has almost no directivity, and is therefore reflected depending on the angle of incidence of the stimulation excitation light with respect to the metal reflection layer. Since the light returns to the stimulable phosphor layer side and repeats scattering again to excite the stimulable phosphor over a wide range, the sharpness of the image is not improved much.

In addition, in JP-A-56-12600, the above-mentioned JP-A-56-12600
No. 11393 discloses a method of providing a white pigment light-reflecting layer on one side of a stimulable phosphor layer in which a stimulable phosphor is dispersed in a binder instead of a metal light-reflecting layer. ing. According to this method, by changing the portion of the photostimulable phosphor layer that enters inside from the surface of the photostimulable excitation light incident side into a white pigment light-reflecting layer, the photostimulable phosphor layer The thickness of the layer can be made thinner, thereby making it possible to suppress the spread of the photostimulable excitation light within the photostimulable phosphor layer, thereby obtaining a highly sharp radiation image.

However, this method also uses a part of the stimulable phosphor layer, which is made by dispersing a stimulable phosphor, which is a type of white pigment, in a binder.
It is simply replaced with a white pigment light-reflecting layer formed by dispersing a white pigment in a binder. Therefore, although this method has the effect of suppressing the spread (scattering) of the photostimulable excitation light within the layer by reducing the thickness of the photostimulable phosphor layer, the white pigment light-reflecting layer The stimulable excitation light that reaches the stimulable phosphor layer is diffusely reflected on the surface of the white pigment light-reflecting layer, or is scattered within the white pigment light-reflecting layer, reflected toward the stimulable phosphor layer, and then scattered again within the stimulable phosphor layer. Since the stimulable phosphor is excited over a wide range, image sharpness is not significantly improved.

As mentioned above, the reciprocity between sensitivity to radiation and image sharpness in conventional radiation image exchange panels has hardly been improved, and there has been a strong desire for improvement.

(Problems to be Solved by the Invention) As described above, a conventional radiation image conversion panel having a light reflecting layer made of a metal or a white pigment on one side of a stimulable phosphor layer has radiation sensitivity and image No one has been found that is excellent in both sharpness and sharpness.

Therefore, the present inventor aims to provide a radiation image conversion panel that is excellent in both radiation sensitivity and image sharpness.

[Structure of the Invention] (Means for Solving the Problems) A radiation image conversion panel (hereinafter referred to as "conversion panel") of the present invention
) is a radiation image conversion panel having a light blocking layer and/or a light scattering layer and a photostimulable phosphor layer (hereinafter referred to as "stimulable layer") on a support in this order, It is characterized in that the light blocking layer is composed of a ceramic powder coating layer.

Further, the conversion panel of the present invention includes a structure in which both the light blocking layer and the light scattering layer are made of ceramic powder.

Next, the present invention will be explained in detail.

FIG. 1 is a schematic cross-sectional view of the conversion panel of the present invention. In FIG. 1, 1 is a support, 2 is a light blocking layer, 3 is a light scattering layer, and 4 is a photostimulable layer.

The light blocking layer is for preventing excitation light from entering the support, thereby eliminating scattering of excitation light inside the support and improving sharpness. By constructing this light blocking layer with a ceramic powder coating layer, the light blocking layer is formed in thermodynamic equilibrium with the support, so a stable layer can be formed and no peeling occurs. . Further, since it is formed by a coating method, the layer thickness can be made uniform over a wide area, and furthermore, it is possible to select an arbitrary layer thickness.

If a light scattering layer is further provided on the light blocking layer, it is possible to prevent deterioration of sharpness and increase sensitivity, thereby making it possible to provide a panel with high sensitivity and high sharpness.

By forming this light-scattering layer with a ceramic powder coating layer, a stable light-blocking layer and light-scattering layer can be formed on the support.

The light blocking layer preferably has a transmittance of excitation light of 5% or less, more preferably 1% or less.

AI2□ is the ceramic powder that forms the light blocking layer.
03 T t Oa, Ajl! N, S iC,C
Examples include powders such as.

Although the particle size of these ceramic powders is not particularly limited, it is preferably 100 μm or less, since if it is too large, the formed light blocking layer will become too thick or its surface will become rough.

In addition to the above-mentioned ceramic powder, the light-blocking layer may be made of materials capable of scattering particles and forming a vine interface or layer, such as pigments, porous metals, grained metals, frosted glass, or opal glass. can do.

The light scattering layer preferably has an average reflectance of 50% or more, more preferably 70% or more, with respect to stimulated excitation light and/or light in the stimulated emission region, and as a constituent material, the following white pigment is used. can be given. Examples of preferable white pigments include T10□ (anatase type, rutile type), MgO12P
bCO,・Pb(OH1,,Ba5O,,'AI2.O
,, MFX (where MI is at least one of Ba, Sr, and Ca, and X is at least one of CI2 and Br), CaCO5, ZnO1S
bz 03 , S i Os , ZrO*, Nb ,
O, lithopone (BaSO4+Zn5), magnesium silicate, basic lead silicate, basic lead phosphate, aluminum silicate, and the like. These white pigments are
Because it has a strong cocooning power and a large refractive index, it reflects light,
By refraction, light is easily scattered and the sensitivity of the resulting conversion panel is significantly improved.

As stimulable phosphors for conversion panels, there are similar materials such as divalent europium-activated alkaline earth metal fluorohalide phosphors, rare earth element-activated rare earth oxyhalide phosphors, and thallium-activated alkali halide phosphors. When using a stimulable phosphor that emits light even in the ultraviolet region, M 11F X, anatase-type T i O2, MgO12PbCO□・Pb
(OH1, B a S O4 and Al2I O are preferred.

The average particle diameter of the pigment is preferably 0.05 to 50 μm, more preferably 0.1 to 10 μm.

The thickness of the light blocking layer and the light scattering layer is preferably 1 to 500 μm, more preferably 10 to 200 μm. If this thickness is too small, the respective effects will not be sufficient, and if it is too large, the absorption of X cotton will be too large. (results in decreased sensitivity).

The light-blocking layer and the light-scattering layer can be formed by mixing the ceramic powder or a mixture of it and other components with an appropriate binder and forming a coating, such as spraying, dipping, or doctoring. It can be formed by applying a coating method using a blade, screen printing, or other methods.

Examples of the binder used here include polymeric compounds having film-forming properties, such as nitrocellulose, vinyl chloride-vinyl acetate copolymer, and polyurethane. Among these, if you use a paint containing an organometallic polymer such as polytitanocarbosilane, such as Tyrancoat (trade name, manufactured by Ube Industries, Ltd.), it can be made stronger and denser by heat treatment after application. It is more preferable because it can form a light blocking layer and a light scattering layer with high .

In the conversion panel of the present invention, for the purpose of further improving the sharpness of the obtained image, the conversion panel may be colored on the side where the stimulated excitation light is incident rather than the light scattering layer.

In the present invention, the coloring applied to the side where the photostimulated excitation light is incident rather than the light scattering layer of the conversion panel covers the entire layer of the photostimulated layer,
Or the surface layer part of the nuclear layer, the layer part close to the light scattering layer,
It is applied to either the undercoat layer, the protective layer, or two or more of these.

Alternatively, a colored layer is provided on the layer surface or between the core layer and the light scattering layer.

The coloring agent used for the coloring is a coloring agent that absorbs at least a part of the photostimulated excitation light for causing the photostimulable phosphor to emit photostimulable light, and in particular, the type of the applied photostimulable phosphor. According to A, it is preferable that the conversion panel has light absorption characteristics such that the average reflectance for light in the stimulated excitation wavelength region is smaller than the average reflectance for light in the stimulated emission wavelength region.

From the viewpoint of image sharpness, it is better for the colorant to have a high absorption rate for light in the wavelength range of the photostimulable excitation light of the stimulable phosphor (lower average reflectance of the conversion panel for light in the wavelength range). (From the viewpoint of sensitivity, it is better that the absorption rate of the stimulable phosphor for light in the stimulated emission wavelength range is small (the average reflectance of the conversion panel for light in the wavelength range is large).

More specifically, the average reflectance of a conversion panel colored with a colorant to light in the stimulated emission wavelength range is 20% or more of the average reflectance of an equivalent uncolored conversion panel to light in the same wavelength range. Preferably, the average reflectance of a conversion panel colored with a colorant to the wavelength range of photostimulated excitation light is 95% or less of the average reflectance of an equivalent uncolored conversion panel to light in the same wavelength range. It is preferable.

The coloring agent may be either an organic or inorganic coloring agent, but in terms of hue, blue to green coloring agents are useful.

As an organic colorant, Zapon Fast Blue 3G (
(manufactured by Sahekist), Nistrol Prill Blue N-3RL
(manufactured by Sumitomo Chemical), D&C Blue No. 1 (manufactured by National Aniline), Spirit Blue (manufactured by Hodogaya Chemical), Oil Blue No. 603 (manufactured by Orient), Kitten Blue A (manufactured by Ciba Geigy), Chiron Blue GL
H (fffl Tsuchiya L Dosei), Lake Blue AFH (Kyowa Sangyo), Primodianine 6GX (Inabata Sangyo), Prill Acid Green 6BH (Hodogaya Chemical), Cyanine Blue BNRS (Toyo Ink), Lionol Blue SL ( (manufactured by Toyo Ink) etc. are used.

Also, color index No. 24411°2316
0.74180.74200.22800.23150
．． 23155.24401.14880, l 5050
．． 15706, l 5707.17941°74' 2
20.13425, l 336 L, 13420.11
836.74140°74380.74350.744
Organic metal complex salt colorants such as 60 and the like may also be mentioned.

Inorganic colorants include ultramarine blue, cobalt blue, cerulean blue, chromium oxide, T102-Zn0-Co
Examples include o-N i O pigments.

The above-mentioned "stimulable phosphor" refers to the first stimulable phosphor that is irradiated with the first light or high-energy radiation and then stimulated by prior stimulation, thermal, mechanical, chemical, electrical, etc.ff1 (stimulable excitation). The present invention refers to a phosphor that exhibits stimulated luminescence corresponding to the irradiation amount of light or high-energy radiation, but from a practical standpoint, it is preferably a phosphor that exhibits stimulated luminescence by stimulated excitation light of 500 nm or more. Examples of the stimulable phosphor used in the conversion panel include phosphor represented by Ba5On:Ax described in JP-A No. 48-80487, and MgS described in JP-A No. 48-80488. O42Ax
A phosphor represented by 5rSO*:Ax described in JP-A No. 48-80489, a phosphor represented by JP-A-Sho 5
Nass 04 described in No. 1-29889
, Mn, D to Ca SO4 and B a SO4, etc.
A phosphor containing a small amount of y and Tb, Bed, Li, which is described in JP-A-52-30487,
Phosphors such as F, Mg5O+ and CaF, JP-A-5
Li*B40? described in No. 3-39277? :
Phosphors of Cu and Ag, described in JP-A No. 54-47883 L Lgo IB x Oil: Cu and LitO・IB*0w1s: Phosphors of Cu, Ag, etc., U.S. Patent No. 3.859.527 SrS: Ce, Sm, SrS: Eu, Sm,
LagOtS: Eu, Sm and (Zn, Cd)S:
Examples include phosphors represented by Mn and x. In addition, ZnS: Cu described in JP-A No. 55-12142
.

pb phosphors, barium aluminate phosphors having the formula Ba0-xAI2to3:Eu, and alkaline earth metal silicate phosphors having the formula MIIO-XSiO228.

In addition, the general formula (Bat-x-yMgxCay) FX: Eu” described in JP-A No. 55-12143
The general formula of the alkaline earth fluorohalide phosphor described in JP-A-55-12144 is LnO
X: Phosphor represented by xA, JP-A-55-1214
The general formula described in No. 5 is (Bat-, M”x)F
X: Phosphor represented by yA, JP-A-55-8'43
The general formula described in No. 89 is BaFX: xCe, y
A phosphor represented by A, a rare earth element-activated divalent metal fluorohalide phosphor whose general formula is MIXFX-xA:yLn described in JP-A-55-160078;
-The formula is ZnS: ACdS: A, (Zn, Cd
)S: A, X and Cds: A, a phosphor represented by X,
A phosphor represented by any of the following general formula % formula described in JP-A-59-38278: A phosphor represented by any of the following general formula % formula described in JP-A-59-155487 Alkali halide phosphor expressed in % and JP-A-61-
One mathematical formula MIX described in No. 228400: xBi
Examples include bismuth-activated alkali halide phosphors represented by:

In particular, alkali halide phosphors are preferable because they can easily form a stimulable layer by methods such as vapor deposition and sputtering.

However, the stimulable phosphor used in the conversion panel of the present invention is not limited to the above-mentioned phosphor, but is a phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with stimulable excitation light. Any phosphor may be used.

The thickness of the stimulable layer of the conversion panel of the present invention varies depending on the radiation sensitivity of the intended conversion panel, the type of stimulable phosphor, etc., but is selected from the range of 1 to 1000 μm, more preferably 20 to 800 μm. Preferably.

As a method for forming the stimulable layer, a vapor deposition method is more preferable in order to enhance the effects of the present invention. Examples of the vapor deposition method include a vapor deposition method, a sputtering method, and a CVD method. In the vapor deposition method, after the support is placed in a vapor deposition apparatus, the apparatus is evacuated to a vacuum level of about 10-' Torr, and then the stimulable phosphor is heated and evaporated using a resistance heating method, an electron beam method, etc. It is deposited on the surface of a support to a desired thickness, forming a stimulable layer that does not contain a binder. In the sputtering method, similarly to the vapor deposition method, after the support is placed in the sputtering device, the inside of the device is once evacuated to a vacuum level of about 1 O-'Torr, and then an inert gas such as Ar or Ne is used as the sputtering gas. Gas is introduced into the sputtering equipment to
The stimulable phosphor is deposited on the surface of the support by sputtering using a gas pressure of about rr and using the stimulable phosphor as a target. The CVD method is a method for obtaining a stimulable layer on a support by decomposing a target stimulable phosphor or an organometallic compound containing a stimulable phosphor raw material with energy such as heat or high-frequency power. .

Examples of the support include ceramic plates such as alumina, glass plates such as chemically strengthened glass and crystallized glass, metal plates such as aluminum, iron, copper, and chromium, or metal plates having a coating layer of the metal oxide. Although preferred, the support may be a plastic film such as a polyester film, a polyethylene terrestrial film, or a polycarbonate film.The support is not limited to a single layer, and may have a multilayer structure of two or more layers.

The layer thickness of these supports varies depending on the material of the support used, but is generally 80 to 5000 μm, and more preferably 80 to 300 μm from the viewpoint of handling.
It is 0 μm.

The surface of these supports may be smooth, or may be matte for the purpose of improving adhesion with the photostimulable layer or light scattering layer. It may be an uneven surface 21 as shown in (b), or it may be a structure in which isolated tile-like plates 23 are laid out as shown in (b).
In the case of FIG. 2(a), the photostimulable layer is subdivided by the uneven surface 21 as shown in the cross-sectional view of FIG. 2(c), so that the sharpness of the image is further improved. In the case of FIG. 2(b), the photostimulable layer is deposited while maintaining the contour of the tile-like plate 23 of the support, so that the photostimulable layer is as shown in the cross-sectional view of FIG. 2(d). Since it is composed of columnar blocks 25 of stimulable phosphor separated by cracks 26, the sharpness of the image is further improved.

In the conversion panel of the present invention, a protective layer for physically or chemically protecting the photostimulable layer is generally provided on the side of the photostimulable layer opposite to the side on which the light scattering layer is provided. This protective layer may be formed by directly applying a protective layer coating liquid onto the photostimulable layer, or may be formed by adhering a separately formed protective layer onto the photostimulable layer. , protective layer materials include cellulose acetate, nitrocellulose,
Common protective layer materials such as polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, vinylidene chloride, nylon, etc. are used. Further, this protective layer may be formed by laminating inorganic materials such as SiC, SiOx, SiN, A2803, etc. by a vapor deposition method, a sputtering method, etc. The layer thickness of these protective layers is generally 0.1- The thickness is preferably about 100 μm.

The conversion panel of the present invention provides excellent sharpness, graininess and sensitivity when used in the radiographic image conversion method shown schematically in FIG. That is, in FIG. 3, 41 is a radiation generating device, 42 is a subject, 43 is a conversion panel of the present invention, 44 is a photostimulation excitation light source, and 45 is a photoelectric conversion device that detects stimulated luminescence emitted from the conversion panel. , 46 is 45
47 is a device for displaying the reproduced image; 48 is a filter that separates stimulated excitation light and stimulated luminescence and allows only stimulated luminescence to pass through. It should be noted that the elements after 45 may be of any type as long as they can reproduce the optical information from 43 as an image in some form, and are not limited to the above.

As shown in FIG. 3, radiation from the radiation generating device 41 enters the conversion panel 43 of the present invention through the subject 42. This incident radiation is absorbed by the photostimulation layer of the conversion panel 43, and its energy is accumulated to form an accumulated radiation transmission image. In the conversion panel 43 of the present invention, the conversion panel 43 of the present invention does not contain a binder in the photostimulation layer and has a high directivity of the photostimulation layer. At the same time, diffusion of the photostimulable excitation light in the photostimulable photomaterial layer is suppressed.

Since the strength of the emitted stimulated luminescence is proportional to the amount of accumulated radiation energy, this optical signal is photoelectrically converted by a photoelectric conversion device 45 such as a photomultiplier tube, and an image reproduction device 46
By reproducing the image as an image and displaying it on the single-image display device 47, a radiographic image of the subject can be observed.

(Example) Next, the present invention will be explained by examples.

Example 1 On the surface of crystallized glass with a thickness of lam placed horizontally, A
l2203-Tyranocoat containing 40% TiO□ particles (
Product name, manufactured by Ube Industries ■) using a doctor blade.
It was applied uniformly to 0 um. Thereafter, after air drying for 30 minutes, the temperature was raised to 100° C. at a temperature increase rate of 5° C./win to dry the coating film, thereby forming a light blocking layer.

Next, on the surface of the light blocking layer, a 50 μm thick light scattering layer was formed using Tyrannocoat (trade name, manufactured by Ube Industries, Ltd.) containing A (2-Os) in the same manner as for the light blocking layer.

Next, an alkali halide stimulable phosphor (RbBr: 0.0006T42) was placed in a water-cooled crucible in which the support having the light-blocking layer and the light-scattering layer was placed in a vapor deposition device, and the crucible was pressed. It was molded into the shape of.

The evaporator was then evacuated and the stimulable phosphor was evaporated by supplying power to a zero-order EB gun at a vacuum level of 5×IO-'Torr.

Vapor deposition was terminated when the thickness of the photostimulable layer reached 300 μm, and a conversion panel of the present invention comprising a support, a light blocking layer, a light scattering layer, and a photostimulable layer was obtained.

Furthermore, various conversion panels A each comprising a support, a light blocking layer, a light scattering layer, and a photostimulating layer were manufactured by changing the thickness of the photostimulating layer in the range of 100 to 600 μm.

The conversion panel A of the present invention was evaluated for radiation sensitivity and image sharpness by the method described below, and the results were expressed as curve A in FIG.
Shown as

After irradiating the radiation/green sensitivity conversion panel with X-rays at a tube voltage of 5 okvp, the panel is stimulated with a semiconductor laser beam (780°), and the stimulated luminescence emitted from the stimulated layer is detected by a photodetector. (Photomultiplier tube) Photoelectric conversion was performed, and this signal was reproduced as an image by an image reproducing device and analyzed.

x# of the conversion panel from the signal size! The sensitivity to was measured. Note that the sensitivity to X-rays is the same as that of conversion panel A of the present invention.
The values are shown as relative values, with those having a photostimulated layer thickness of 300 μm set as 100. Further, the modulation transfer function (MTF) of the image was measured from the obtained image to evaluate sharpness. Note that the modulation transfer function (MTF) has a spatial frequency of 2 cycles/1
This is the value of I11.

Example 2 In Example 1, after drying the coating film, 5'C/win
Example 1 was carried out in the same manner as in Example 1, except that the coating film was heat-treated by increasing the temperature to 750° C. at a heating rate of .

Various conversion panels B of the present invention were produced, each comprising a support, a light-blocking layer, a light-scattering layer, and a photostimulation layer.

The conversion panel B of the present invention was evaluated for radiation sensitivity and image sharpness in the same manner as in Example 1, and the results are shown in curve B in Figure 4.
Shown as

Example 3 In Example 2, a support, a light blocking layer, a light scattering layer, and a photostimulable layer were constructed in the same manner as in Example 2, except that the light scattering layer was formed using Tyranno coat containing Z r Oi particles. Various conversion panels C were manufactured.

The radiation sensitivity and image sharpness of the conversion panel C of the present invention were evaluated in the same manner as in Example 1, and the results were expressed as curve C in Figure 4.
Shown as

Comparative Example 1 Various comparative conversion panels P consisting of a support and a photostimulable layer were manufactured in the same manner as in Example 1, except that the photostimulable layer was directly deposited on the crystallized glass. did.

The radiation sensitivity and image sharpness of the comparative conversion panel P were evaluated in the same manner as in Example 1, and the results were expressed as the curve P in FIG.
Shown as

Comparative Example 2 A support, a light scattering layer,
Various comparative conversion panels Q were manufactured consisting of photostimulable layers.

The radiation sensitivity and image sharpness of the conversion panel Q of Comparative Example 2 were evaluated in the same manner as in Example 1, and the results are shown as curve Q in FIG.

As is clear from FIG. 4, the conversion panels A, B of the present invention,
Compared to the conventional conversion panels P and Q, C has a higher image sharpness if the radiation sensitivity is the same, and conversely, if the image sharpness is the same, the radiation sensitivity is higher.

[Effects of the Invention] As described above, by forming a light blocking layer and a light scattering layer on a support using a ceramic powder coating layer.

Both sensitivity and sharpness were improved. Further, since the layer thicknesses of the light blocking layer and the light scattering layer can be made uniform and peeling does not occur, a conversion panel with uniform sensitivity and sharpness can be manufactured.

[Brief explanation of the drawing]

FIG. 1 shows a schematic sectional view of the conversion panel of the present invention, and FIG.
Figures (a) and (b) show examples of the shape of the layer surface on which the stimulable phosphor of the support of the conversion panel of the present invention is deposited;
) and (d) show cross sections when a photostimulable layer is formed on the layer surface, and FIG. 3 shows a schematic diagram of a radiation image conversion method using the conversion panel of the present invention. FIG. 4 is a diagram showing the relationship between relative sensitivity and image sharpness in conversion panels A, B, and C of the present invention and comparison conversion panels P and Q. 21 and 22...Support 23...-Tiled treatment 24 and 25--Photostimulation layer 27...Light scattering layer 26...Crack 41...Radiation generating device 42...Subject 43... - Conversion panel 44... Stimulating excitation light source 48... - Filter Fig. 2 (G) (b) (C) (d) Fig. 4

Claims (2)

[Claims] (1) On the support, a light blocking layer and/or a light scattering layer,
and a radiation image conversion panel having stimulable phosphor layers in this order, wherein the light blocking layer is composed of a ceramic powder coating layer. (2) A radiation image conversion panel characterized in that, in addition to the light blocking layer, a light scattering layer is further composed of a ceramic powder coating layer.