JPH0682858B2 - Radiation image detection method - Google Patents

Description

The present invention relates to a radiation image detecting method. More specifically, the present invention relates to a radiation image detecting method using a combination of a stimulable phosphor and a photosensitive element.

Conventionally, a so-called radiographic method, which combines a radiographic film having an emulsion layer made of a silver salt photosensitive material and an intensifying screen (intensifying screen), has been used as a method of detecting a radiographic image of a subject and obtaining an image. Has been done. As one of the methods for replacing the above-mentioned conventional radiography, for example, U.S. Pat.No. 3,859,527 and JP-A-55-121.
There is known a radiation image conversion method using a stimulable phosphor as described in Japanese Patent Publication No. 45 and the like. This method allows the stimulable phosphor to absorb the radiation transmitted through the subject or the radiation emitted from the subject, and then the phosphor is time-series by electromagnetic waves (excitation light) such as visible light and infrared light. The excitation of the radiation energy causes the radiation energy accumulated in the phosphor to be emitted as fluorescence (stimulated luminescence), and the fluorescence is detected.

So far, in the radiation image conversion method, the radiation image is detected by using a radiation image conversion panel containing a stimulable phosphor (a stimulable phosphor sheet). It has been proposed to photoelectrically read the energy image of (1) by a radiation image reading (reading) device. Further, in the radiation image reading apparatus, a photomultiplier tube is usually used as a photodetector as disclosed in Japanese Patent Laid-Open No. 56-11395, and the tip of this photomultiplier tube is used. Is provided with a light guide sheet for collecting the fluorescence emitted from the surface of the radiation image conversion panel and guiding it to the photodetector.

That is, the radiation transmitted through the subject or the radiation emitted from the subject is absorbed by the phosphor layer of the radiation image conversion panel, and the radiation image of the subject or the subject is formed on the panel as an accumulated image of radiation energy. It Next, the accumulated image formed on this panel is emitted as stimulated emission (fluorescence) by being excited by electromagnetic waves (excitation light) such as visible rays and infrared rays in the radiation image reading device. The emitted fluorescence is guided through a light guide sheet, photoelectrically read by a photomultiplier and converted into an electrical signal, and the obtained electrical signal is used to image a radiation image of a subject or a subject. can do.

The radiation image conversion method described above has an advantage in that a radiation image having a large amount of information can be obtained with a much smaller exposure dose than in the case of using a conventional radiography method. Therefore, this radiographic image conversion method is very useful in direct medical radiography such as X-ray photography for the purpose of medical diagnosis.

However, the reading of the radiation image conversion panel is conventionally performed by irradiating the panel with light having a small beam diameter such as a laser beam in a time series, that is, scanning with a laser beam (main scanning or sub-scanning), At this time, the fluorescence emitted from the panel is detected by using a photodetector such as a photomultiplier tube and converted into an electric signal. This reading operation takes a time (tens of seconds) that cannot be ignored. I need it.

Further, in reading out the radiation image conversion panel, in order to detect fluorescence emitted in time series from each phosphor particle group of the radiation image conversion panel irradiated with the excitation light, it is usually under irradiation of the excitation light. The panel is being transferred (sub-scan or main-scan). Therefore, the operation of detecting (reading out) the radiation images accumulated in the radiation image conversion panel is complicated.

Furthermore, when a light guide sheet or the like is used in combination with a photomultiplier tube in order to efficiently detect the fluorescence emitted from the radiation image conversion panel, the reading device becomes complicated, resulting in operational problems. Is likely to occur.

Therefore, the main object of the present invention is to provide a radiation image detecting method in which the above-mentioned problems in the radiation image converting method using a stimulable phosphor are solved, or a radiation image is reduced in the drawbacks. To do.

The above-mentioned object is a phosphor containing a photosensitizing member and a photostimulable phosphor in which a large number of photosensitive elements are regularly arranged in a two-dimensional manner for radiation transmitted through a subject or emitted from a subject. Layer and an insulating layer provided between the light detection member and the phosphor layer, which transmits stimulating light and does not transmit excitation light,
Alternatively, after being absorbed by a phosphor layer of a radiation image detector having a laminate composed of a combination of an insulating layer which transmits stimulable light and a filter layer which transmits stimulable light and does not transmit excitation light, the phosphor is then absorbed. The layer is irradiated with electromagnetic waves (excitation light),
This can be achieved by the radiation image detecting method of the present invention, which comprises releasing the radiation energy accumulated in the phosphor layer as photostimulable light and photoelectrically reading the photostimulable light by the photosensitive element.

That is, according to the study of the present inventor, using a radiation image detector having a photodetection member composed of a large number of photosensitive elements and a phosphor layer composed of a stimulable phosphor provided on the photodetection member, Radiation such as X-rays transmitted through the subject or emitted from the subject is made incident on the phosphor layer of this detector, and the energy of the radiation is absorbed by the stimulable phosphor in the phosphor layer. By irradiating the phosphor layer with light in the excitation wavelength region of the stimulable phosphor, the fluorescence (stimulated luminescence) emitted from the phosphor layer is received by the photosensitive element of the detector and converted into an electric signal. It has been found that the image information regarding the radiation image of the subject or the subject can be directly obtained as an electric signal.

Therefore, according to the radiation image detecting method of the present invention, as compared with the radiation image reading methods proposed so far, since the photosensitive element integrated with the phosphor layer is used as the photodetector, The radiation image information can be obtained as an electric signal for each pixel of a large number of photosensitive elements under the irradiation of excitation light, so that the detection time of the radiation image is greatly shortened.

Further, the radiation image detector used in the present invention is provided with a large number of photosensitive elements which are regularly arranged two-dimensionally so as to cover one surface of the phosphor layer, and are irradiated with excitation light. In the readout operation of the radiation image conversion panel, the fluorescence emitted from the surface of the phosphor layer is detected at each pixel of the photosensitive element adjacent to the phosphor layer, that is, the detection of the radiation image is made into a solid state. It is not necessary to transfer the panel, and the detection of the radiation image is simplified.

Furthermore, since it is not necessary to install a light guide sheet or the like for collecting the fluorescence emitted from the panel surface as in the conventional case, it is possible to miniaturize the reading device, and the radiation image as described above is used. In the read operation of the conversion panel, it is possible to solve the problem such as the adverse effect on the image quality caused by the mechanical transportation of the panel or the detector.

This also means that the radiation image can be detected with high sensitivity even when the intensity of the radiation transmitted through the subject or emitted from the subject is weak, for example, in the measurement of autoradiography. Can also be used effectively.

The present invention will be described in detail below.

The radiation image detector used in the present invention is basically composed of a light detecting member in which a large number of photosensitive elements are regularly arranged two-dimensionally, and a phosphor layer provided thereon. is there.

The light detecting member is a member in which a large number of photosensitive elements are regularly arranged in the horizontal direction to form a plane. The photosensitive element used for the light detecting member is, for example, a light receiving portion for receiving the fluorescence emitted from the phosphor layer, and a charge obtained by photoelectric conversion in the light receiving portion to be output in time series as an electric signal. A known solid-state image sensor using an amorphous semiconductor or the like can be used as the photosensitive element.

An example of such a solid-state image sensor is a MOS (Metal Oxide).
de Semiconducter), CCD (Charged Coupled Devic
e), BBD (Bucket Brigade Device), CID (Charge Iso)
sensors such as lated device). Of these, MOS is particularly preferable. Further, examples of the photoconductive material used in this solid-state image pickup element include amorphous silicon (α-Si), ZnO, and CdS.

A phosphor layer is provided on the light detecting member with an insulating layer interposed therebetween. Examples of the material of the insulating layer include light-transmitting and insulating substances such as glass and transparent polymer substances. It is desirable that this insulating layer has a function as a filter that transmits only light in the wavelength region of stimulated emission and cuts light in the wavelength region of excitation light. The function of such an insulating layer as an optical filter is, for example,
It can be provided by coloring the insulating layer with a colorant having the above-mentioned photoselective transparency.

Alternatively, the filter layer having the above-mentioned light transmittance may be provided between the insulating layer and the phosphor layer.

The phosphor layer is usually a layer composed of a binder that contains and supports stimulable phosphor particles in a dispersed state.

The photostimulable phosphor used in the present invention is a phosphor that exhibits stimulated emission upon irradiation with excitation light after being irradiated with radiation as described above, but has a wavelength of 400 from a practical viewpoint.
A phosphor that exhibits stimulated emission in the wavelength range of 300 to 500 nm by excitation light in the range of to 800 nm is desirable. Examples of such stimulable phosphors include SrS: Ce, described in US Pat. No. 3,859,527.
Sm, SrS: Eu, Sm, ThO ₂ : Er, and La ₂ O ₂ S: Eu, a phosphor represented by a composition formula such as Sn, ZnS: Cu described in JP-A-55-12142. Pb, Ba
O ・ xAl ₂ O ₃ : Eu [however, 0.8 ≦ x ≦ 10] and M ²⁺ O
XSiO ₂ : A [However, M ²⁺ is Mg, Ca, Sr, Zn, Cd, or
Ba, A is Ce, Tb, Eu, Tm, Pb, Tl, Bi, or Mn
And x is 0.5 ≦ x ≦ 2.5] and the like, a phosphor represented by a composition formula described in JP-A-55-12143 (Ba
_1-xy , Mg _x , Ca _y ) FX: aEu ²⁺ [wherein X is at least one of Cl and Br, and x and y are 0
<X + y ≦ 0.6 and xy ≠ 0, and a is 10 ⁻⁶ ≦ a ≦
The phosphor represented by the composition formula of 5 × 10 ⁻² ], LnOX: xA described in JP-A-55-12144 (where Ln is at least La, Y, Gd, and Lu). 1, X is at least one of Cl and Br, A is at least one of Ce and Tb, and x is 0 <x
A phosphor represented by the composition formula of <0.1] is described in JP-A-55-12145 (Ba _1-x , M
^II _x ) FX: yA [M ^II is Mg, Ca, Sr, Zn, and C
at least one of d, X is at least one of Cl, Br, and I, and 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], the phosphor represented by the composition formula: M ^II FX · xA described in 160078 JP: y
Ln [However, M ^II is Ba, at least one of Ca, Sr, Mg, Zn, and Cd, A is BeO, MgO, CaO, SrO, BaO, Z
nO, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TlO ₂ , ZrO ₂ , G
At least one of eO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and ThO ₂ , Ln is Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb,
At least one of Er, Sm, and Gd, X is Cl, B
at least one of r and I, wherein x and y are 5 × 10 ⁻⁵ ≦ x ≦ 0.5, and 0 <y ≦ 0.2, respectively] No. 116777 (Ba _1-x , M
^II _x ) F ₂ · aBaX ₂ : yEu, zA [where M ^II is beryllium,
At least one of magnesium, calcium, strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, A is at least one of zirconium and scandium, and a, x, y, and z is 0.5 ≦ a ≦ 1.25,
0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 10 ⁻²
And a phosphor represented by the composition formula: (Ba _1-x , M
^II _x ) F ₂ · aBaX ₂ : yEu, zB [where M ^II is beryllium,
At least one of magnesium, calcium, strontium, zinc, and cadmium; X is at least one of chlorine, bromine, and iodine;
x, y, and z are 0.5 ≦ a ≦ 1.25 and 0 ≦ x ≦, respectively.
1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 2 × 10 ⁻¹ ], which is described in JP-A-57-23675 (Japanese Patent Application Laid-Open No. 57-23675). Ba _1-x ,
M ^II _x ) F ₂ · aBaX ₂ : yEu, zA [M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, and X is at least one of chlorine, bromine, and iodine. , A is at least one of arsenic and silicon, and a, x,
y and z are 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 1 respectively
0 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ and 0 <z ≦ 5 × 10 ⁻¹ ], which is described in Japanese Patent Application No. 56-167498 by the present applicant. M ^III OX: xCe [M ^III is Pr, Nd, Pm, Sm, E
at least one trivalent metal selected from the group consisting of u, Tb, Dy, Ho, Er, Tm, Yb, and Bi, X is one or both of Cl and Br, and x
Is 0 <x <0.1], a phosphor represented by the composition formula, Ba _1-x M _{x / 2} L _{x / 2} FX described in Japanese Patent Application No. 57-89875 by the present applicant: yEu ²⁺ [where M is Li,
Represents at least one alkali metal selected from the group consisting of Na, K, Rb, and Cs; L represents Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, A
represents at least one trivalent metal selected from the group consisting of l, Ga, In, and Tl; X represents at least one halogen selected from the group consisting of Cl, Br, and I; and x represents 10 ^-2 ≤ x ≤ 0.5, y is 0 <y ≤ 0.1], a phosphor represented by the composition formula BaFX · xA: yEu ² described in Japanese Patent Application No. 57-137374 filed by the present applicant. ⁺ [Where X is Cl, Br, and I
At least one halogen selected from the group consisting of; A is a calcined product of a tetrafluoroborate compound;
And x is 10 ⁻⁶ ≦ x ≦ 0.1 and y is 0 <y ≦ 0.1], which is described in Japanese Patent Application No. 57-158048 filed by the present applicant. BaFX ・ xA: yEu ²⁺ [where X is Cl, Br, and I]
Is at least one halogen selected from the group consisting of; A is at least one selected from the group consisting of hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid mono- or divalent metal hexafluoro compound group A fired product of a compound of
x is 10 ⁻⁶ ≦ x ≦ 0.1, y is 0 <y ≦ 0.1], a phosphor represented by the composition formula BaFX · xNaX described in Japanese Patent Application No. 57-166320 filed by the present applicant. ′: AEu ²⁺ [wherein X and X ′ are at least one of Cl, Br, and I, respectively, and x and a are 0 <x ≦ 2 and 0 <a ≦, respectively.
0.2]], a phosphor represented by the composition formula, M ^II FX.xNaX ′: yEu ²⁺ : zA described in Japanese Patent Application No. 57-166696 filed by the present applicant (where M ^II is Ba, S
at least one alkaline earth metal selected from the group consisting of r and Ca; X and X ′ are respectively Cl, B
r and at least one halogen selected from the group consisting of I; A is at least one transition metal selected from V, Cr, Mn, Fe, Co, and Ni; and
x is 0 <x ≦ 2, y is 0 <y ≦ 0.2, and z is 0 <z
≦ 10 ⁻² ], the phosphor represented by the composition formula, M ^II FX · aM ^I X ′ · bM ′ ^II X ″ ₂ ·, described in Japanese Patent Application No. 57-184455 filed by the present applicant. CM ^III X ₃ x
A: yEu ²⁺ [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca: M ^I is from the group consisting of Li, Na, K, Rb, and Cs M ′ ^II is at least one divalent metal selected from the group consisting of Be and Mg; M ^III is at least one selected from the group consisting of Al, Ga, In, and Tl. A is a trivalent metal; A is a metal oxide; X is at least one halogen selected from the group consisting of Cl, Br, and I; X ′, X ″, and X
Is at least one halogen selected from the group consisting of F, Cl, Br, and I; and a is 0 ≦ a ≦
2, b is 0 ≦ b ≦ 10 ⁻² , c is 0 ≦ c ≦ 10 ⁻² , and a + b
+ C ≧ 10 ⁻⁶ ; x is 0 <x ≦ 0.5, y is 0 <y ≦ 0.2], and the like.

The stimulable phosphor used in the present invention is not limited to the above-mentioned phosphor, and any phosphor can be used as long as it exhibits stimulated emission when irradiated with excitation light after irradiation with radiation. It may be.

However, the stimulable phosphor must be used in combination with the photosensitive element so that the wavelength range of the stimulated emission overlaps with the light absorption wavelength range of the photoconductive material used for the light receiving portion of the photosensitive element. That is, the photostimulable phosphor and the photoconductive material used in the present invention must be selected so that at least a part of the emission wavelength region of photostimulable light and at least a part of the light absorption wavelength region of the photoconductive material overlap. I have to. For example, when α-Si is used as the photoconductive material, the stimulable phosphor is preferably a phosphor having a stimulated emission wavelength near 600 nm. Further, it has a stimulable emission wavelength in the near-ultraviolet or visible region, such as a divalent europium-activated alkaline earth metal fluorohalide-based phosphor (having a peak emission wavelength of about 390 nm) as a stimulable phosphor. When a phosphor is used, ZnS and CdS are preferable as the photoconductive material.

Examples of the binder for the phosphor layer are proteins such as gelatin, polysaccharides such as dextran, or natural polymer substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, vinylidene chloride / chloride. Vinyl copolymer, polymethylmethacrylate, vinyl chloride / vinyl acetate copolymer, polyurethane, cellulose acetate butyrate,
Examples thereof include binders represented by synthetic polymer substances such as polyvinyl alcohol and linear polyester.

The phosphor layer can be formed on the insulating layer (or filter layer) by the following method, for example.

First, the above-described stimulable phosphor particles and a binder are added to an appropriate solvent (for example, lower alcohol, ketone, ester, ether), and they are mixed sufficiently to form phosphor particles in the binder solution. A coating liquid uniformly dispersed is prepared.

The mixing ratio of the binder and the stimulable phosphor particles in the coating liquid varies depending on the characteristics of the intended radiation image detector, the type of photosensitive element, the type of phosphor particles, etc., but generally the binder and the phosphor are used. The mixing ratio with the particles is selected in the range of 1: 1 to 1: 100 (weight ratio), and particularly preferably in the range of 1: 8 to 1:40 (weight ratio).

The coating liquid contains a dispersant for improving the dispersibility of the phosphor particles in the coating liquid, and also improves the binding force between the binder and the phosphor particles in the formed phosphor layer. Various additives such as plasticizers for mixing may be mixed.

The coating liquid containing the stimulable phosphor particles and the binder prepared as described above is then uniformly applied to the surface of the insulating layer to form a coating film of the coating liquid. This coating operation can be performed by using an ordinary coating means such as a doctor blade, a roll coater or a knife coater. Then, the formed coating film is gradually heated and dried to complete the formation of the phosphor layer on the insulating layer. The layer thickness of the phosphor layer varies depending on the characteristics of the intended radiation image detector, the type of phosphor particles, the mixing ratio of the binder and the phosphor particles, etc., but is usually 20 μm to
Set to 1 mm. However, this layer thickness is preferably 50 to 500 μm.

The phosphor layer does not necessarily have to be formed by directly applying the coating liquid on the insulating layer as described above, and for example, separately applying the coating liquid on a sheet such as a glass plate, a metal plate or a plastic sheet. Then, after the phosphor layer is formed by drying, the insulating layer and the phosphor layer may be joined by pressing the phosphor layer on the insulating layer or using an adhesive.

Further, the phosphor layer does not necessarily have to be formed by dispersing stimulable phosphor particles in a binder, and for example, by stimulating the stimulable phosphor particles onto the insulating layer by vacuum deposition or the like. It may be formed.

It is preferable that a transparent protective film for protecting the phosphor layer from physical impact and chemical alteration is provided on the phosphor layer. This protective film may be, for example, a cellulose derivative such as cellulose acetate or nitrocellulose; or polymethylmethacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate,
Polyvinyl acetate, vinyl chloride / vinyl acetate copolymer,
It is formed from a synthetic polymer substance such as polyethylene terephthalate, polyethylene, vinylidene chloride, and polyamide. The thickness of the protective film is preferably about 3 to 20 μm.

Next, regarding the radiation image detecting method of the present invention, an example of a partial vertical sectional view of the radiation image detector shown in FIG. 1 of the accompanying drawings and an overall circuit diagram of the radiation image detector shown in FIG. A specific description will be made with reference to FIG.

FIG. 1 is a vertical cross-sectional view of one pixel of a radiation image detector including a light detecting member and a phosphor layer provided on the light detecting member.

In FIG. 1, the radiation image detector is composed of a photosensitive element 1, an insulating layer 2 and a phosphor layer 3 made of a stimulable phosphor in order. The photosensitive element 1 includes a photodiode 4 which is a light receiving section and a MOS: FET (Metal Oxide Semiconduct) which is a transfer section.
er: Field Effect Transistor) 5. The photodiode 4 is composed of a metal layer 6 of aluminum or the like, which is ground, a p-type α-Si: H layer 7, an i-type α-Si: H layer 8 and a transparent electrode layer 9 of tin dioxide (SnO ₂ ) in this order. Also MOS: FET5
Is a metal layer 10, 11 such as aluminum provided on both ends.
And an α-Si: H layer 1 provided inside these metal layers in order.
2. An insulating layer 13 made of silicon (SiO ₂ ) and a transfer electrode 14 made of aluminum or the like. This metal layer 11 is a drain and is connected to the transfer register. Meanwhile, the transfer electrode
A gate 14 is connected to the scan pulse generator. The insulating layer 2 has a light-transmitting property such that only light in the wavelength region of stimulated emission emitted from the phosphor layer 3 is transmitted and light in the wavelength region of excitation light is cut.

FIG. 2 is a schematic circuit diagram of the light detection member of the radiation image detector. One pixel 21 corresponds to FIG.
It is composed of 22 and a transfer unit 23. Each transfer unit is connected to the scan pulse generator 24 and the transfer register 25, respectively. The transfer register 25 is provided with an output terminal 26.

Further, the radiation that has passed through the subject (or, if the subject itself emits radiation, that is, in the case of a subject, the radiation emitted from the subject) is made incident on the phosphor layer side of the radiation image detector. That is, the radiation having the intensity corresponding to the radiation transmission image of the subject is incident from the lower side of FIG. The incident radiation is absorbed by the phosphor layer 3. That is, an accumulated image (a kind of latent image) of radiation energy corresponding to the radiation image of the subject is formed on the phosphor layer 3.

Next, when the radiation image detector is irradiated with electromagnetic waves in the excitation wavelength region of the stimulable phosphor contained in the phosphor layer 3 from the phosphor layer 3 side, the accumulated image of radiation energy formed on the phosphor layer 3 is obtained. , Emitted as fluorescence (stimulated luminescence). This fluorescence is proportional to the intensity of the radiation energy absorbed in the phosphor layer 3. Only the emitted fluorescence passes through the insulating layer 2 which also serves as a filter and is received by the photodiode 4 of the photosensitive element 1 which is a light detecting member, and a signal charge is generated in the photodiode 4. In this way, a signal charge proportional to the emission brightness of fluorescence, that is, the intensity of the radiation incident on the phosphor layer of the detector is generated in each pixel of a large number of photosensitive elements of the radiation image detector.

Then, in the circuit diagram shown in FIG. 2, when a transfer pulse is sent from the scan pulse generator 24 to each pixel in the uppermost row, the switch of each transfer section in the uppermost row is in the “ON” state (in FIG. A voltage is applied to 14 and a current flows between the metal layers 10 and 11). That is, the signal charge generated in the photodiode 4 of FIG. 1 is transferred through the MOS: FET5. Therefore, the signal charge of each pixel in the top row is sent to the transfer register 25 at the same time. From the output terminal 26 of the transfer register 25, an electric signal for each pixel is taken out in time series.

In this way, from the top row to the bottom row in FIG.
A transfer pulse is sent to each column from the scanning pulse generator 24, and an electric signal from each pixel of each column having radiation image information is output from the output terminal 26 in time series.

The electric signal output from the radiation image detector is amplified by the amplifier and reproduced as an image by the image reproducing device. The electric signal obtained here may be subjected to image processing such as spatial frequency processing, gradation processing, averaging processing, reduction processing, and expansion processing, if desired. Then, the obtained image may be recorded by a recording medium or may be displayed by an image display device. As the recording medium, there can be used, for example, one that scans a photographic photosensitive material with a laser beam or the like to optically record, and one that records on a heat-sensitive recording material using a heat ray. Further, as an image display device, an electronic display on a CRT, a CRT, etc.
It is possible to use a display device based on various principles such as a device for recording a radiation image displayed on a video printer or the like on a video printer or the like. The radiation image information of the subject may be recorded and stored on a magnetic tape or the like.

In the radiation image detector used in the present invention, as the photosensitive element, for example, one in which one pixel has a size of about 200 μm × 200 μm can be used. When the size of the radiation image detector is, for example, the size of a conventional radiation intensifying screen (430 mm × 354 mm), it is composed of 2150 × 1750 pixels. Α-Si is preferable as the material of the uniform photosensitive element forming such a large area, and it is desirable that the area of the light receiving portion is as large as possible. In the radiation image detector having the above structure and size, the pulse output from the scanning pulse generator is preferably about 3 kHz, for example.

However, the radiation image detector used in the present invention and the photosensitive element included therein are not limited to the above size. Further, the radiation image detector used in the present invention is not limited to the detector exemplified above, a phosphor layer containing a stimulable phosphor, and a stimulable light from this phosphor layer. It can take any form as long as it has a large number of light-sensitive elements arranged regularly in a two-dimensional manner for reading.

Further, the radiation image detecting method of the present invention is not limited to the above-exemplified method. For example, as a method for detecting the radiation image accumulated and recorded in the phosphor layer of the radiation image detector, the method described above is used. Before this operation, a preliminary operation may be performed by irradiation of a weak electromagnetic wave in order to measure the amount of stimulated emission, and based on the result of this preliminary operation, the amplification factor of the obtained electric signal is set and the reproduced image is reproduced. It is also possible to set processing conditions.

[Brief description of drawings]

FIG. 1 is a schematic partial vertical cross-sectional view of a radiation image detector used in the radiation image detecting method of the present invention. 1: Photosensitive element, 2: Insulating layer, 3: Phosphor layer, 4: Photodiode, 5: MOS: FET, 6: Metal layer, 7: p-type α-Si: H layer, 8: i-type α
-Si: H layer, 9: transparent electrode layer, 10, 11: metal layer, 12: α-Si: H
Layer, 13: Insulator layer, 14: Transfer electrode FIG. 2 is a schematic circuit diagram of a radiation image detector used in the radiation image detecting method of the present invention. 21: One pixel, 22: Light receiving part, 23: Transfer part, 24: Scan pulse generator, 25: Transfer register, 26: Output terminal

Claims (4)

[Claims] 1. A phosphor containing a photostimulable phosphor and a photosensing member having a large number of photosensitive elements arranged regularly in a two-dimensional manner for radiation transmitted through a subject or emitted from a subject. A phosphor layer of a radiation image detector having a layered body and an insulating layer which is provided between the light detection member and the phosphor layer and which transmits excitation light and does not transmit excitation light. Then, the phosphor layer is irradiated with excitation light to release the radiation energy accumulated in the phosphor layer as stimulated light, and the stimulated light is photoelectrically read by the photosensitive element. Image detection method. 2. The radiation image detecting method according to claim 1, wherein the phosphor layer contains a divalent europium-activated alkaline earth metal fluorohalide-based phosphor. 3. A phosphor containing a photosensitizing member and a photostimulable phosphor in which a large number of photosensitive elements are arranged two-dimensionally in a regular manner in a radiation transmitted through a subject or emitted from a subject. Radiation image detection including a layer, and a laminate including an insulating layer that is provided between the photodetection member and the phosphor layer and that transmits stimulating light and a filter layer that transmits stimulating light and does not transmit excitation light After being absorbed by the phosphor layer of the container, the phosphor layer is irradiated with excitation light to release the radiation energy accumulated in the phosphor layer as stimulated light, and the stimulated light is emitted from the photosensitive element. A method for detecting a radiation image, which comprises photoelectrically reading. 4. The radiation image detecting method according to claim 3, wherein the phosphor layer contains a divalent europium-activated alkaline earth metal fluorohalide-based phosphor.