JP2589979B2 - Radiation image conversion panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a radiation image conversion panel having a phosphor layer formed by dispersing a phosphor in a binder.

BACKGROUND OF THE INVENTION

Radiation images such as X-ray images are widely used for disease diagnosis and the like. In order to obtain this radiation image, the radiation transmitted through the subject is radiated to a radiation image conversion panel having a phosphor layer (fluorescent screen), thereby generating visible light. In the same manner as described above, a film using a silver salt is irradiated and a radiograph obtained by developing the film is used. On the other hand, in recent years, a method of directly taking out an image from a phosphor layer without using a film coated with a silver salt has been proposed.
In this method, radiation transmitted through a subject is irradiated on a radiation image conversion panel having a phosphor layer (stimulable phosphor layer), and the phosphor absorbs the radiation, and then the phosphor is irradiated with light or the like. By exciting with heat energy, this phosphor emits the radiation energy accumulated by the above-mentioned absorption as fluorescence (stimulated luminescence), and this fluorescence is detected and imaged. Specifically, for example, U.S. Pat. No. 3,859,527 and JP-A-55-12144 disclose a radiation image conversion method using a stimulable phosphor and using visible light or infrared light as stimulating excitation light. In this method, a radiation image conversion panel having a stimulable phosphor layer formed on a support is used. A latent image is formed by accumulating radiation energy corresponding to the radiation transmittance of the laser beam, and thereafter the stimulable phosphor layer is scanned with stimulating excitation light to emit the accumulated radiation energy of each part. Is converted into light, and an image is obtained by an optical signal based on the intensity of the light. This final image may be reproduced as a hard copy or reproduced on a CRT. A radiation image conversion panel having a phosphor layer used in these radiation image conversion methods has high radiation absorption and light conversion rates (hereinafter, referred to as “radiation sensitivity” inclusive of both). Good granularity and high sharpness are required. By the way, in the above-mentioned radiation image conversion method,
"Spread of light in the phosphor layer" has a great effect on the sharpness of an image. That is, in a radiation image conversion panel having a fluorescent screen, when the instantaneous light emission (light emission at the time of irradiation) of the phosphor in the fluorescent screen spreads when passing through the fluorescent screen, the phosphor is irradiated on the film using the silver salt. The spread of the light spreads and the sharpness of the radiograph developed from the film becomes poor. On the other hand, in a radiation image conversion panel having a stimulable phosphor layer, the spread of luminescence of the stimulable phosphor does not greatly affect the sharpness of an image, but the stimulability of stimulable excitation light is high. The spread in the phosphor layer greatly affects the sharpness of the image. That is, since the radiation image information accumulated in the stimulable phosphor is time-sequentially extracted, the stimulating light emitted by the stimulating excitation light irradiated at a certain time (ti) is preferably all collected and the time is measured. Is recorded as an output from a pixel (xi, yi) on the radiation image conversion panel that had been irradiated with stimulating excitation light, and the spread of luminescence of the stimulable phosphor greatly affects the sharpness of the image. There is no. However, when the stimulable excitation light spreads in the stimulable phosphor layer due to scattering or the like, and also excites the stimulable phosphor existing outside the irradiated pixel (xi, yi), the above (xi, yi Since the output from a region wider than the pixel (xi, yi) is recorded as the output from the pixel, the spread of the stimulable excitation light in the stimulable phosphor layer increases the sharpness of the image. Have a big impact. In any case, in the radiation image conversion method, "spread of light in the phosphor layer" has a great effect on the sharpness of the image, and improvement of "spread of light in the phosphor layer" is strongly desired. Was.

[Object of the invention]

The present invention has been made in view of the above, and an object of the present invention is to provide a radiation image conversion panel that can provide a highly sharp radiation image without lowering sensitivity. .

Configuration of the Invention

An object of the present invention described above is to provide a radiation image conversion panel having a stimulable phosphor layer formed by dispersing a stimulable phosphor in a binder, wherein the average particle diameter of the phosphor is γ (μm). , Γ ± 1 / 2γ (μm), wherein the phosphor particles have a particle size in the range of 73 wt% or more of the total phosphor in the phosphor layer. You. That is, in the present invention, if the phosphor particles having a particle diameter in the range of γ ± 1 / 2γ (μm) are less than 73% by weight (non-monodisperse), the particle diameter with respect to the average particle diameter The variation width of the distribution (based on weight average) is large, so that the mean free path of light by small particles is short and the scattering (spreading) of light is controlled, but at the same time, the scattering of light by large particles also increases, resulting in sharpness No effect on gender occurs. On the other hand, if the phosphor particles having a particle diameter in the range of γ ± 1 / 2γ (μm) are 73 wt% or more (monodisperse) of the whole, the non-monodisperse phosphor having the same average particle diameter is used. As compared with the phosphor layer composed of, the light scattering in the phosphor layer is suppressed, and the sharpness is improved without lowering the sensitivity. Also, γ ± 1 /
Phosphor particles having a particle size in the range of 2γ (μm)
It is preferably at least 0 wt%. The greater the proportion of particles contained in the range of γ ± 1 / 2γ (μm) with respect to the whole particles, the greater the effect of the present invention. In the present invention, the average particle size of the phosphor particles is
It is selected in the range of 0.1 to 100 (μm), more preferably 0.5 to 40 (μm). Hereinafter, the case where the phosphor is a stimulable phosphor will be described. FIG. 1 (a) shows various particle size distributions of the stimulable phosphor. Distribution curves A and D give a particle size distribution suitable for the present invention. In order to produce a stimulable phosphor having a particle size distribution according to the present invention, there are the following methods, but the present invention is not limited thereto. The steps of the method for producing a stimulable phosphor having a particle size distribution according to the present invention are broadly divided into preparation of raw materials, baking and pulverization (washing, drying, classification, and the like as necessary). As a first method, there is a method in which the stimulable phosphor is crushed or classified under appropriate conditions. As a second method, before firing, the average particle size and particle size distribution of the raw material are adjusted by the synthesis conditions of the raw material, pulverization, and classification, and then the raw material is fired, and then the first method is applied as necessary. It is a method of manufacturing by. An advantage of this manufacturing method is that a decrease in sensitivity due to processing such as pulverization after firing can be suppressed. In the case where the stimulable phosphor is composed of an alkali halide as a base, it is possible to more easily obtain a stimulable phosphor having an excellent particle size distribution by utilizing the property that the solubility of the alkali halide in water is high. Can be. That is, after the stimulable phosphor material is dissolved or suspended in water and mixed well, the water is evaporated by heating, drying under reduced pressure, vacuum drying, and spray drying. At this time, the average particle size and the particle size distribution can be controlled by the evaporation rate of water. Another method is to dissolve the stimulable phosphor raw material in water and add this aqueous solution to a solvent in which the stimulable phosphor is insoluble or a solvent having a lower solubility than water, thereby producing a stimulable phosphor. A method of precipitating body material is employed. At this time, the average particle size and the particle size distribution can be controlled by the type of the solvent and / or the addition conditions. Further, in the above method, an activator raw material having high solubility in water is dissolved in water at the same time as the stimulable phosphor raw material. Can be synthesized. Moreover, since there is no sintering of the stimulable phosphor material by firing, the particle size distribution is not disturbed. In addition, since steps after firing can be omitted, it is preferable from the viewpoint of manufacturing cost. If the stimulable phosphor thus obtained is fired, the luminous intensity can be further increased. The stimulable phosphor is irradiated with the first light or high-energy radiation and then stimulated by light, thermal, mechanical, chemical, or electrical stimulation (stimulation excitation). A phosphor that emits stimulable light corresponding to the radiation dose is preferably a phosphor that emits stimulable luminescence by stimulating excitation light of 500 nm or more from a practical viewpoint.
Examples of the stimulable phosphor include BaSO ₄ : Ax (where A is at least one of Dy, Tb and Tm, and x is 0.001 ≦ x <1 mol) described in JP-A-48-80487. %, MgS described in JP-A-48-80488.
O ₄ : Ax (where A is either Ho or Dy, x
Is a phosphor represented by 0.001 ≦ x <1 mol%, and SrSO ₄ : Ax described in JP-A-48-80489 (where A is D
y, at least one of Tb and Tm, and x is 0.001 ≦
x <1 mol%. ), A phosphor represented by
A phosphor obtained by adding at least one of Mn, Dy and Tb to Na ₂ SO ₄ , CaSO ₄ and BaSO ₄ described in JP-A-51-29889; BeO described in JP-A-52-30487 , LiF, MgSO ₄
And CaF phosphors such as _2, JP 53-39277 No. Li ₂ described in B ₄ O _7: Cu, phosphors such as Ag, Li ₂ O as described in JP-A-54-47883・ (B ₂ O ₂ ) x: Cu (where x is 2 <x ≦
3) and Li ₂ O · (B ₂ O ₂ ) x: Cu, Ag (where x is 2 <x ≦
Phosphors such as 3), SrS: Ce, Sm, SrS: Eu, Sm, La ₂ O ₂ S: Eu, Sm and (Zn, Cd) described in US Pat. No. 3,859,527.
A phosphor represented by S: Mn, X (where x is a halogen) is exemplified. Further, ZnS: C described in JP-A-55-12142
u, Pb phosphor, whose general formula is BaO.xAl ₂ O ₃ : Eu (where 0.8 ≦ x ≦ 1
0) and a barium aluminate phosphor represented by the general formula: M II O · xSio ₂ : A (where M II is Mg, Ca, Sr, Zn, Cd or B
a and A is at least one of Ce, Tb, Eu, Tm, Pb, Tl, Bi and Mn, and x is 0.5 <x <2.5. ), An alkaline earth metal silicate-based phosphor represented by the formula: The general formula described in JP-A-55-12143 is (Ba ₁ -x-yMgxCay) FX: eEu ²⁺ (where X is at least one of Br and Cl, x, y
And e are respectively 0 <x + y ≦ 0.6, xy ≠ 0 and 10 ⁻⁶ ≦
It is a number that satisfies the condition of e ≦ 5 × 10 ⁻² . Alkaline earth fluoride halide phosphor represented by the formula:
The general formula described in No. 4 is LnOX: xA (where Ln is at least one of La, Y, Gd and Lu, and X is Cl
And / or Br, A is Ce and / or Tb, and x is 0 <x <
Represents a number that satisfies 0.1. ), A phosphor represented by
The general formula described in No. 5-12145 is (Ba ₁ -xM IIx) FX: yA (where M II is at least one of Mg, Ca, Sr, Zn and Cd, and X is Cl, Br And at least one of I
A is at least one of Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb and Er, and x and y are numbers satisfying the conditions of 0 ≦ x ≦ 0.6 and 0 ≦ y ≦ 0.2. Represent. ), A phosphor represented by
55-84389, wherein the general formula is BaFX: xCe, yA (where X is at least one of Cl, Br and I;
Is at least one of In, Tl, Gd, Sm and Zr;
x and y are respectively 0 <x ≦ 2 × 10 ⁻¹ and 0 <y ≦ 5 ×
10 ^-2 . ), A general formula described in JP-A-55-160078, wherein M II FX · xA: yLn (where M II is at least one of Mg, Ca, Ba, Sr, Zn and Cd) one, A is BeO, MgO, CaO, SrO, BaO, ZnO, 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 , Ta ₂ O ₅ and
At least one of ThO ₂ , Ln is Eu, Tb, Ce, Tm, Dy, Pr,
At least one of Ho, Nd, Yb, Er, Sm and Gd,
X is at least one of Cl, Br and I, and x and y are numbers satisfying the conditions of 5 × 10 ⁻⁵ ≦ x ≦ 0.5 and 0 ≦ y ≦ 0.2, respectively. Rare earth element activation 2)
Valence metal fluorohalide phosphor, with general formulas ZnS: A, CdS:
A, (Zn, Cd) S: A, ZnS: A, X and CdS: A (where A is Cu, A
g, Au, or Mn, and X is halogen. A phosphor represented by any of the following general formulas xM ₃ (PO ₄ ) ₂ · NX ₂ : yA M ₃ (PO ₄ ) ₂ : yA described in JP-A-57-148285. M and N are each at least one of Mg, Ca, Sr, Ba, Zn and Cd, X is at least one of F, Cl, Br and I, A is Eu, Tb, Ce, Tm, Dy, Pr , Ho, Nd, Yb, Er, Sb, Tl, Mn
And at least one of Sn. X and y are numbers satisfying the conditions of 0 <x ≦ 6 and 0 ≦ y ≦ 1. )
In phosphor represented by the general formula nReX ₃ · mAX ₂ of either the following _{': xEu nReX 3 · mAX 2} ': xEu, ySm ( wherein, Re is La, Gd, Y, at least one of Lu, the alkaline At least one of earth metals, Ba, Sr, and Ca, and X and X 'represent at least one of F, Cl, and Br.
And y are 1 × 10 ⁻⁴ <x <3 × 10 ⁻¹ , 1 × 10 ⁻⁴ <y <1
It is a number that satisfies the condition of × 10 ^-1 and n / m is 1 × 10 ^-3 <7
The condition of × 10 ^{-1 is} satisfied. ) And the following general formula: MIX • aM II X ₂ ′ · bM III X ₃ : cA (where MI is at least one alkali metal selected from Li, Na, K, Rb and Cs) Yes, M II is BE, Mg, Ca, Sr, Ba, Zn,
It is at least one kind of divalent metal selected from Cd, Cu and Ni. M III is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
at least one selected from o, Er, Tm, Yb, Lu, Al, Ga and In
Species of trivalent metal. X, X 'and X "are at least one halogen selected from F, Cl, Br and I. A is Eu, T
At least one metal selected from b, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. A is a numerical value in the range of 0 ≦ a <0.5, and b is 0
B is a numerical value in the range of 0.5 <c, and c is a numerical value in the range of 0 ≦ c <0.2. And the like. However, the stimulable phosphor used in the radiation image conversion panel is not limited to the above-described phosphor, but may be any phosphor that exhibits stimulable emission when irradiated with stimulating excitation light after irradiation with radiation. Any phosphor may be used as long as it is used. Next, a method for manufacturing a radiation image conversion panel using a stimulable phosphor having a particle size distribution will be described. The stimulable phosphor layer is formed of stimulable phosphor particles having a particle diameter in the range of γ ± 1 / 2γ with respect to an average particle diameter of γμm of 80 wt% or more and other constituent materials. It is formed by applying and drying a phosphor paint which is dispersed and dissolved in an adhesive solution. When the film formed by the phosphor paint has good film-forming properties and sufficient strength, the support may not be necessary. In general, the phosphor paint is applied on the support. If a protective layer is provided, it may be applied to a separately formed and prepared protective layer film. Further, a panel may be formed by bonding the protective layer film or the support to the surface of the dried stimulable phosphor layer provided on the support or the protective layer film. Further, a form may be adopted in which a protective layer paint is prepared for the stimulable phosphor layer provided on the support, and this is applied to the stimulable phosphor layer. The stimulable phosphor is mixed with a suitable binder in a suitable solvent and mixed 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 coating material is dispersed to prepare a coating material, and the coating material is applied on a support or a protective layer using a coating machine such as a doctor blade, a roll coater, or a knife coater. The radiation image conversion panel may be a stimulable phosphor layer group including one or more stimulable phosphor layers containing at least one of the aforementioned stimulable phosphors. The stimulable phosphor contained in each stimulable phosphor layer may be the same or different. The stimulable phosphor layer is formed by applying at least two or more stimulable phosphors having different average particle diameters so as to have a predetermined particle size distribution array of appropriate phosphor particles. Is also good. In the particle size distribution arrangement of the phosphor particles, a distribution arrangement in which large particles are arranged on the stimulating excitation light incident side is more preferable in terms of sensitivity. Examples of the binder include proteins such as gelatin,
Polysaccharides such as dextran or gum arabic, polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, vinylidene chloride-vinyl chloride copolymer, polymethyl methacrylate, vinyl chloride-vinyl acetate copolymer, polyurethane, cellulose acetate butyrate, polyvinyl alcohol, etc. The binder used in the usual layer constitution is used. Generally, the binder is used in an amount of 0.01 to 1 part by weight based on 1 part by weight of the stimulable phosphor. However, from the viewpoint of the sensitivity and sharpness of the obtained radiation image conversion panel, the amount of the binder is preferably small, and the range of 0.03 to 0.2 part by weight is more preferable in view of the balance with ease of application. The thickness of the stimulable phosphor layer of the radiation image conversion panel depends on the characteristics of the intended radiation image conversion panel, the type of the stimulable phosphor, the mixing ratio between the binder and the stimulable phosphor, and the like. , 10 μm to 1000 μm, more preferably 10 μm to 500 μm. For the purpose of improving the sharpness of the radiation image conversion panel, a white powder may be dispersed in the stimulable phosphor layer of the radiation image conversion panel as disclosed in JP-A-55-164447. Also, as disclosed in JP-A-55-163500, a stimulable phosphor layer of a radiation image conversion panel is provided. The layer may be colored with a coloring agent that absorbs stimulating light. In the radiation image conversion panel, when the stimulable phosphor layer has no self-supporting ability, a support for supporting the stimulable phosphor layer is provided. As the support, various polymer materials, glass, metal and the like are used, and plastic films such as cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, and polycarbonate film, aluminum sheet, and iron sheet are used. And a metal sheet such as a copper sheet or a metal sheet having a coating layer of the metal oxide. 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, in these supports, an undercoat layer may be provided on the surface on which the stimulable phosphor layer is provided for the purpose of improving the adhesion to the stimulable phosphor layer. The thickness of the support varies depending on the material of the support to be used and the like.
2000 μm, more preferably 80 from the viewpoint of handling.
μm to 1000 μm. In the radiation image conversion panel, generally, the stimulable phosphor layer is physically or scientifically protected on the surface opposite to the surface on which the support of the stimulable phosphor layer is provided. Is preferably provided. As the material of the protective layer, cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene,
Polyvinylidene chloride, nylon, polytetrafluoroethylene, polytrifluoride-ethylene chloride, tetrafluoroethylene-
Conventional protective layer materials such as propylene hexafluoride copolymer, vinylidene chloride-vinyl chloride copolymer, and vinylidene chloride-acrylonitrile copolymer are used. Further, this protective layer is made of SiC, SiO ₂ , S
An inorganic material such as iN or Al ₂ O ₇ may be stacked. Generally, the thickness of these protective layers is preferably about 0.1 μm to 100 μm. If the stimulable phosphor coating has film-forming properties and the formed film has sufficient rigidity, the above-mentioned support and / or protective layer may not be necessary. The radiation image conversion panel of the present invention provides excellent sharpness and sensitivity when used in the radiation image conversion method schematically illustrated in FIG. That is, in FIG. 2, 21 is a radiation generator, 22 is a subject, 23 is a radiation image conversion panel of the present invention, 24 is a stimulating excitation light source, and 25 is a stimulating luminescence emitted from the radiation image conversion panel. 26 is a device that reproduces the signal detected in 25 as an image, 27 is a device that displays the reproduced image, 28 is a device that separates stimulated excitation light and stimulated emission and only stimulated emission This is a filter that transmits light. Note that after 25, it is sufficient that the optical information from 23 can be reproduced as an image in some form, and it is not limited to the above. As shown in FIG. 2, radiation from the radiation generator 21 passes through the subject 22 through the radiation image conversion panel of the present invention.
It is incident on 23. The incident radiation is absorbed by the stimulable phosphor layer of the radiation image conversion panel 23, the energy is accumulated, and an accumulation image of the radiation transmission image is formed. Next, the accumulated image is excited by stimulating light from the stimulating light source 24 and emitted as stimulating light. Since the intensity of the emitted stimulating luminescence is proportional to the amount of the accumulated radiation energy, the optical signal is photoelectrically converted by a photoelectric conversion device 25 such as a photomultiplier tube, and the image is reproduced and displayed.
By reproducing the image by the image display 26 and displaying the image by the image display device 27, the radiographic image of the subject can be observed.

【Example】

Next, the present invention will be described in more detail by way of examples. Example 1 Table 1 and FIG. 1 (a) show the particle size distribution of various stimulable phosphors used in the production of the radiation image conversion panel of the present invention or in the production of a comparative radiation image conversion panel. The composition of each stimulable phosphor is RbBr; Tl.
In FIG. 1 (a) and Table 1, the stimulable phosphors A, B, C, D
Was manufactured as follows. RbBr is dissolved in water to make an aqueous solution. This aqueous solution was added to a solvent in which RbBr was insoluble, and RbBr having various particle sizes was obtained by changing the type of the solvent and the addition conditions. A predetermined amount of an activator was added to the mixture, and the mixture was calcined. Thereafter, pulverization and classification were performed as necessary to obtain stimulable phosphors A, B, C and D. Stimulable phosphors E and F
Is obtained by performing pulverization and classification as needed before and after firing. Next, a radiation image conversion panel was manufactured using the stimulable phosphor as follows. First, 13 parts by weight of the stimulable phosphor is dispersed in 1 part by weight of polyvinyl butyral (binder) using a solvent in which butyl acetate and butanol are mixed at a weight ratio of 3: 1, and this is placed horizontally on polyethylene terephthalate. Film (support)
A radiation image conversion panel having a film thickness of about 300 μm is prepared by uniformly applying the composition using a wire bar and drying naturally. Thus, the stimulable phosphors A,
Radiation image conversion panels A and D of the present invention corresponding to D were prepared. Comparative radiation image conversion panels B, C, E and F corresponding to the stimulable phosphors B, C, E and F were also prepared in the same manner. After irradiating each radiation image conversion panel thus obtained with X-rays having a tube voltage of 80 KVp for 10 mR, the semiconductor laser light (7
Photostimulated at 80 nm), photostimulated light emitted from the photostimulable phosphor layer is photoelectrically converted by a photodetector (photomultiplier tube), and this signal is reproduced as an image by an image reproducing device. Recorded above. The sensitivity of the radiation image conversion panel to X-rays was examined based on the magnitude of the signal, and the modulation transfer function (MTF) of the image was examined based on the obtained image. The results are shown in Table 2. In Table 2, the sensitivity to X-rays is shown as a relative value with the comparative radiation image conversion panel F as 100, and the modulation transfer function (MTF) is a value when the spatial frequency is 2 cycles / mm. According to Table 2, the radiation image conversion panel A of the present invention has a higher sensitivity to X-rays and gives a radiation image with the highest sharpness as compared with the comparative radiation image conversion panels B, C, E and F. . Further, the radiation image conversion panel D of the present invention has an extremely high sensitivity to X-rays, and has an image close to the sharpness of another comparative panel E whose sharpness is much higher than the lowest sharpness of the comparative panel F. give. Example 2 BaFBr: Eu stimulable phosphors P and Q having different particle size distributions were produced by appropriate pulverization and classification, and FIG. 1 (b)
Table 3 shows the particle size distribution. This stimulable phosphor P, Q
A radiation image conversion panel P of the present invention and a comparative radiation image conversion panel Q were prepared in the same manner as in Example 1 using
The relative value and sharpness were determined as 100, and the results are shown in Table 4. From Tables 3 and 4, RbBr: Tl was used as the stimulable phosphor.
As with the case of using the radiation image conversion panel P, the radiation image conversion panel P of the present invention gave an image with extremely high sharpness, while having the same sensitivity to X-rays as the comparative radiation image conversion panel Q.

【The invention's effect】

In the present invention described in detail above, γ ± 1 / 2γ (μm)
The phosphor particles having a particle diameter within the range of (1) are 73 wt% or more (monodisperse) of the total, so that the fluorescent layer has the same average particle diameter and is not monodispersed. This has the effect of suppressing the scattering of light in the body layer and improving the sharpness without lowering the sensitivity.

[Brief description of the drawings]

FIG. 1 is a view showing the particle size distribution of stimulable phosphor particles in the radiation image conversion panel of the present invention. FIG. 2 is a schematic diagram illustrating a radiation image conversion method using the radiation image conversion panel of the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumio Shimada 1 Sakuracho, Hino City Konishi Roku Photo Industry Co., Ltd. 59-138999 (JP, A)

Claims (1)

(57) [Claims] In a radiation image conversion panel having a stimulable phosphor layer in which a stimulable phosphor is dispersed in a binder, if the average particle diameter of the phosphor is γ (μm), γ ± 1/2
A radiation image conversion panel, wherein phosphor particles having a particle diameter in the range of γ (μm) account for 73% by weight or more of the entire phosphor in the phosphor layer.