JP2002116514A - Stimulus phosphor sheet, radiation image information reading method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stimulus phosphor sheet which can be exactly aligned of the stimulus phosphor sheet and exciting and detecting means in their depth direction, a radiation image information reading method and device. SOLUTION: The exciting and detecting means of a box shape provided with the grooves of the stimulus phosphor sheet having the linear grooves at both edges on their upper side and a line light source and line sensor read radiation image information from the sheet while moving the sheet in its groove direction in the state that the projections of the exciting and detecting means having the linear projections at both edges on their lower side are meshed with the grooves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a stimulable phosphor sheet, and a method and apparatus for reading radiation image information stored and recorded on the sheet.

[0002]

2. Description of the Related Art When irradiated with radiation such as X-rays, a part of the radiation energy is absorbed and accumulated, and then, when irradiated with electromagnetic waves (excitation light) such as visible light and infrared rays, the accumulated radiation is absorbed. Utilizing a stimulable phosphor (accumulative phosphor) having a property of stimulating light emission according to energy, an object is transmitted through a sheet-shaped stimulable phosphor sheet containing the stimulable phosphor. After temporarily storing and recording radiation image information of the subject or the subject by irradiating the emitted or emitted radiation from the subject, the sheet is scanned with excitation light such as laser light and sequentially emitted as photostimulated emission light, and A radiation image recording / reproducing method comprising photoelectrically reading the stimulated emission light to obtain an image signal is widely used in practice. After the reading of the sheet is completed, the remaining radiation energy is erased, and then the sheet is prepared for the next photographing and used repeatedly.

A stimulable phosphor sheet (also referred to as a radiation image conversion panel) used in a radiation image recording / reproducing method has, as a basic structure, a support and a stimulable phosphor layer provided thereon. is there. However, when the stimulable phosphor layer is self-supporting, a support is not necessarily required. The stimulable phosphor layer is usually composed of a stimulable phosphor and a binder that contains the stimulable phosphor in a dispersed state, but does not include a binder formed by a vapor deposition method or a sintering method. There are also known ones composed only of the phosphor aggregates and those in which a polymer substance is impregnated in the gaps between the stimulable phosphor aggregates. Further, a protective film is usually provided on the upper surface (the surface not facing the support) of the stimulable phosphor layer,
The phosphor layer is protected from chemical alteration or physical impact.

As another method of the above-mentioned radiation image recording / reproducing method, Japanese Patent Application No. 11-372978 by the present applicant discloses that the radiation absorbing function and the energy storage function of the conventional stimulable phosphor are separated. A stimulable phosphor sheet containing at least a stimulable phosphor (energy storage phosphor) and a phosphor (radiation absorption phosphor) that absorbs radiation and emits light in the ultraviolet to visible region. A radiation image forming method using a combination with a fluorescent screen has been proposed. In this method, radiation transmitted through a subject is first converted into light in an ultraviolet or visible region by a radiation absorbing phosphor of the screen or sheet, and the light is then converted to a radiation image by an energy storage phosphor of the sheet. Store and record as information. Next, the sheet is scanned with excitation light to emit stimulated emission light, and the stimulated emission light is photoelectrically read to obtain an image signal. A stimulable phosphor sheet containing such a phosphor for energy storage,
Included in the present invention.

In the above-described radiation image recording / reproducing method (and radiation image forming method), image processing such as gradation processing and frequency processing can be performed on the obtained image signal, and a large amount of information can be obtained with a small irradiation dose. There is an advantage that a radiographic image can be obtained.

[0006] As a method of reading radiation image information emitted as stimulating light, two-dimensional pixel division is performed from the viewpoint of shortening the reading time of stimulating light, reducing the size of the reading device, and reducing the cost. A method has been proposed in which a light-receiving element such as a solid-state image sensor or a semiconductor line sensor is used, and a time-series image signal is formed by an electric circuit. For example, Japanese Patent Publication No. 5-32945 discloses that a light emitted from a fluorescent lamp or the like is irradiated on a stimulable phosphor sheet through a slit to irradiate excitation light linearly (“line excitation”), The emitted stimulated emission light is detected by a line sensor including a large number of photoelectric conversion elements arranged opposite to the excitation light irradiation portion (“line detection”).
An apparatus is described.

When performing line detection, an allowable range occurs at the position of the light receiving surface where a clear image can be obtained because the light-collecting system is an imaging system (this is called a depth of focus). Is very small. As a result, accurate positioning between the sheet and the line sensor is required not only in the plane direction of the stimulable phosphor sheet but also in the depth direction.

Hitherto, positioning in the depth direction has been performed by fixing a table on which the stimulable phosphor sheet is placed and keeping the distance from the table to the line sensor constant.
However, in general, the thickness of the sheet is not strictly constant over the entire surface but has a small difference locally, and fixing the table alone is not sufficient for accurate positioning between the sheet and the line sensor.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stimulable phosphor sheet capable of accurately aligning the stimulable phosphor sheet with the excitation / detection means in the depth direction. . Another object of the present invention is to provide a radiation image information reading method capable of obtaining a high-quality radiation image at high speed by aligning the positions of the stimulable phosphor sheet and the excitation / detection unit in the depth direction. . Still another object of the present invention is to provide a radiation image information reading apparatus capable of accurately aligning the stimulable phosphor sheet with the excitation / detection means in the depth direction.

[0010]

The inventor of the present invention has provided at least one projection on at least one of the stimulable phosphor sheet and the excitation / detection means comprising a line light source and a line sensor to provide a positioning function. It has been found that the position in the depth direction can be accurately adjusted by reading with the top surface of the projection as a reference surface and the two in contact with each other.

The present invention provides a stimulable phosphor sheet having a support and a stimulable phosphor layer provided thereon,
The support is a frame having convex portions on at least both side edges, and has a shape in which a linear groove is provided along the frame on the upper portion of the frame, and the stimulable phosphor layer Is provided inside the frame body, in the stimulable phosphor sheet.

According to a first radiation image information reading method of the present invention, the stimulable phosphor sheet on which the radiation image information is accumulated is recorded by a line sensor comprising a line light source and a plurality of photoelectric conversion elements arranged linearly. And a box-shaped excitation / detection means having a linear projection along the edges on both edges substantially orthogonal to the line sensor below the excitation / detection means. , The groove of the sheet and the protrusion of the excitation / detection means are arranged so as to mesh with each other, and while the sheet is moved in the direction of the groove in the meshed state, a part of the surface of the sheet is emitted from the line light source. The linearly illuminated excitation light is irradiated in a direction substantially perpendicular to the moving direction, and stimulated emission light emitted from the excitation light irradiated portion of the sheet is one-dimensionally received by the line sensor to perform photoelectric conversion. And the output from the line sensor Sequentially read in response to the movement,
The method comprises obtaining radiation image information as an electric image signal.

According to the present invention, there is provided a line light source for linearly irradiating a part of the stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and stimulated emission emitted from the part of the sheet irradiated with the excitation light. A box-shaped excitation / detection means comprising: a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to perform photoelectric conversion by receiving light one-dimensionally, and a lower line sensor Exciting / detecting means provided with linear projections along both edges substantially perpendicular to the edge, and moving the sheet in the direction of the groove in a state where the groove and the projection of the excitation / detecting means are engaged. There is also a radiation image information reading apparatus having scanning means for scanning and reading means for sequentially reading the output from the line sensor in accordance with the movement of the sheet and obtaining radiation image information as an electric image signal.

According to the present invention, there is also provided a stimulable phosphor sheet having a support and a stimulable phosphor layer provided thereon, wherein the support has a frame at least on both side edges. Wherein the projection has a shape in which linear projections are provided along the frame at the top of the frame, and the stimulable phosphor layer is provided inside the frame. There is also a phosphor sheet.

According to a second radiation image information reading method of the present invention, the stimulable phosphor sheet on which the radiation image information is accumulated and recorded is a line sensor in which a line light source and a plurality of photoelectric conversion elements are linearly arranged. And a box-shaped excitation / detection means having a linear groove along both edges substantially perpendicular to the line sensor below the excitation / detection means. The projections of the sheet and the grooves of the excitation / detection means are arranged so as to mesh with each other, and the line light source emits light to a part of the surface of the sheet while moving the sheet in the direction of the projection while meshing. The linearly illuminated excitation light is irradiated in a direction substantially perpendicular to the moving direction, and stimulated emission light emitted from the excitation light irradiated portion of the sheet is one-dimensionally received by the line sensor to perform photoelectric conversion. And the output from the line sensor Sequentially read in response to the movement,
The method comprises obtaining radiation image information as an electric image signal.

According to the present invention, there is provided a line light source for linearly irradiating a part of the stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and stimulated emission emitted from the part of the sheet irradiated with the excitation light. A box-shaped excitation / detection means comprising: a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to perform photoelectric conversion by receiving light one-dimensionally, and a lower line sensor Exciting / detecting means provided with linear grooves along the edges on both edges substantially perpendicular to the sheet, and moving the sheet in the projecting direction with the projections and the grooves of the excitation / detecting means engaged with each other. There is also a radiation image information reading apparatus having scanning means for scanning and reading means for sequentially reading the output from the line sensor in accordance with the movement of the sheet and obtaining radiation image information as an electric image signal.

According to a third radiation image information reading method of the present invention, the stimulable phosphor sheet on which the radiation image information is accumulated and recorded is a line sensor in which a line light source and a plurality of photoelectric conversion elements are linearly arranged. The projections of the sheet are arranged below the box-shaped excitation / detection means provided with and so as to contact the lower part of the excitation / detection means, and the sheet is moved in the projection direction while in contact with the sheet. Irradiating a part of the surface of the sheet with excitation light emitted from the excitation light source linearly in a direction substantially perpendicular to the moving direction, and stimulating light emitted from the excitation light irradiated part of the sheet. The line sensor receives light one-dimensionally, performs photoelectric conversion, and sequentially reads the output from the line sensor in accordance with the movement of the sheet to obtain radiation image information as an electric image signal. is there.

According to the present invention, there is provided a line light source for linearly irradiating a part of the stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a stimulable luminescence emitted from the excitation light irradiated part of the sheet. A box-shaped excitation / detection means comprising a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to receive light one-dimensionally and perform photoelectric conversion; Scanning means for moving in the projection direction in contact with the lower part of the detecting means, and reading means for sequentially reading the output from the line sensor in accordance with the movement of the sheet and obtaining radiation image information as an electric image signal There is also a radiation image information reading device having the same.

In a fourth radiation image information reading method according to the present invention, a stimulable phosphor sheet on which radiation image information is stored and recorded is provided with a line sensor having an excitation light source and a plurality of photoelectric conversion elements arranged linearly. A box-shaped excitation / detection means provided with a linear projection along the edge on both edges substantially perpendicular to the lower line sensor, under the excitation / detection means, The excitation light source emits light on a part of the surface of the sheet while arranging the surface of the sheet and the projection of the excitation / detection means so as to be in contact with each other and moving the sheet in the projection direction in a state of contact. The linearly illuminated excitation light is irradiated in a direction substantially perpendicular to the moving direction, and stimulated emission light emitted from the excitation light irradiated portion of the sheet is one-dimensionally received by the line sensor to perform photoelectric conversion. And the output from the line sensor is used to move the sheet. Depending read sequentially, it is made of be obtained as an electrical image signal radiation image information.

According to the present invention, there is provided a line light source for linearly irradiating a part of a stimulable phosphor sheet on which radiation image information is accumulated and recorded with excitation light, and a photostimulated luminescent light emitted from the excitation light irradiated part of the sheet. A one-dimensionally receiving and performing photoelectric conversion, a box-shaped excitation and detection means comprising a line sensor in which a plurality of photoelectric conversion elements are linearly arranged, the lower line sensor Exciting / detecting means provided with linear projections along both edges substantially orthogonal to each other, and moving the sheet in the frame direction in a state where the surface of the sheet is in contact with the projections of the exciting / detecting means. There is also a radiation image information reading apparatus including a scanning unit and a reading unit that sequentially reads an output from the line sensor in accordance with the movement of the sheet and obtains radiation image information as an electric image signal.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The stimulable phosphor sheet, radiation image information reading method and apparatus of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 (1) is a block diagram showing an example of a radiation image information reading apparatus according to the present invention, and FIG.
It is a front view inside the detection means 20, and (3) is a side view inside the box-shaped excitation / detection means 20.

In FIG. 1, the radiation image information reading apparatus emits excitation light L onto the stimulable phosphor sheet 10 by irradiating the scanning belt 40 with the stimulable phosphor sheet 10 thereon and transporting the sheet 10 in the arrow Y direction, and the sheet 10 is emitted from the sheet 10. Box-shaped excitation / detection means 20 for detecting the stimulated emission light M, and a signal S output from the excitation / detection means 20 corresponding to a part of the sheet 10, and output as an electric image signal. The configuration includes an image information reading unit 30.

At the lower part of the box-shaped excitation / detection means 20, linear projections 21 are formed on both side edges along the arrow Y direction.
a and 21b are provided therein, and an excitation optical system 22 and a detection optical system 25 are provided therein. Excitation optical system 22
Includes a plurality of laser light sources 23 that emit the excitation light L, and a cylindrical lens 24 that condenses the excitation light L emitted from the laser light source 23 into a line extending on the sheet 10 along the arrow X direction. The detection optical system 25 is a refractive index distributed lens array (a lens in which a large number of refractive index distributed lenses are arrayed) that makes the stimulated emission light M emitted from the sheet 10 by condensing the excitation light L a parallel light flux. The excitation light L reflected on the surface of the sheet 10 slightly mixed with the stimulated emission light M transmitted through the selfoc lens array 26 is transmitted through the stimulated emission light M. And a line sensor 28 in which a large number of photoelectric conversion elements 29 are arranged to receive the photostimulated light M transmitted through the excitation light cut filter 27 and perform photoelectric conversion.

The stimulable phosphor sheet 10 is composed of a support 11 and a stimulable phosphor layer 14. The support 11 is formed of a frame having projections (frames) 12a and 12b on both side edges thereof. It has a shape, and the stimulable phosphor layer 14 is provided inside the frame. The stimulable phosphor layer 14 is made of BaFBr:
It is a layer made of Eu stimulable phosphor. Also, the support 11
In the upper portions of the frames 12a and 12b, linear grooves 13a and 13b are provided substantially in the center thereof in parallel with the edges thereof so as to engage with the linear protrusions 21a and 21b of the excitation / detection means 20. Has become.

FIG. 2A shows a stimulable phosphor sheet 10.
FIG. 3 is a schematic cross-sectional view showing a portion where the excitation / detection means 20 of the apparatus is engaged, and FIG. In FIG. 2, frames 12a and 12b of the sheet 10 are shown.
Is determined by the radiation absorptance of the phosphor layer since it corresponds to the thickness of the stimulable phosphor layer 14;
１０００1000 μm, preferably 200 μm
It is in the range of 700 mm. The width e of the frames 12a and 12b is
It is in the range of 1 mm to 30 mm. The depth f of the grooves 13a, 13b is in the range of 100 μm to 10 mm, and the width g is in the range of 500 μm to 30 mm. The thickness h of the base of the support 11 is determined by the rigidity required for the sheet and the support material, but is generally in the range of 100 μm to 10 mm, preferably in the range of 500 μm to 5 mm. The length of the vertical i and the horizontal j on the inner side of the support 11 is determined by the image area required for the sheet. However, in practice, an area larger than the image area is required. This is the above (for example, 1.2 times). Therefore,
The lengths of the vertical i and horizontal j are generally 10 to 10 respectively.
In the range of 0 cm.

Generally, the projection 2 of the excitation / detection means 20
The height k of 1a, 21b is in the range of 100 μm to 30 mm, and its width 1 is in the range of 500 μm to 30 mm.
Regarding the external shape of the box-shaped excitation / detection means 20, in order to make the reader compact, it is preferable that the height and the length in the Y direction are as small as possible, and the length in the X direction is sufficient for the line And the projections 21a, 21b are set so as to mesh with the grooves 13a, 13b of the sheet 10.

In the stimulable phosphor sheet 10, the bottom surface (surface B) of the grooves 12a and 12b of the support 11 serves as a reference surface for reading. On the other hand, the excitation / detection means 2 of the device
Reference numeral 0 indicates that the excitation optical system 22 and the detection optical system 25 are adjusted and arranged with reference to the top surface (A surface) of the projections 21a and 21b. Thus, the distance between the surface of the sheet 10 and the excitation optical system 22 and the detection optical system 25 can be kept constant at all times when the sheet 10 and the excitation / detection means 20 are engaged.

In the present invention, the “engaged state” refers to the bottom surface B of the grooves 13a and 13b of the sheet 10.
And the top surfaces A of the projections 21a and 21b of the excitation / detection means 20 are in contact with each other.

FIG. 3 is a front view showing the excitation optical system 22. A plurality of laser light sources (LED (light emitting diode) arrays) 23 are arranged along the direction of arrow X, and each laser light source 23 emits light in the visible region having a wavelength of 630 to 690 nm. The cylindrical lens 24 condenses the light emitted from each laser light source 23 on the sheet 10 in a linear shape extending along the arrow X direction.

FIG. 4 is a front view showing the detection optical system 25. The selfoc lens array 26 includes the line sensor 2
In the light receiving surface 8, the light emitting area of the stimulated emission light M on the sheet 10 serves as an image surface on which an image is formed in a one-to-one size.

The line sensor 28 includes a large number (for example, 1000 or more) of photoelectric conversion elements (CC
D, charge-coupled devices) 29 are arranged. A large number of photoelectric conversion elements 29 each have a length of 100 μm × width of 10 μm.
It has a light receiving surface of about 0 μm and corresponds to one pixel. Each light receiving surface receives stimulated emission light M emitted from a region of about 100 μm × 100 μm on the surface of the stimulable phosphor sheet 10.

Next, the radiation image information reading method of the present invention will be described in detail by taking as an example the case where the above-described reading device and the stimulable phosphor sheet are used.

First, the stimulable phosphor sheet 10 on which radiation image information of the subject is accumulated and recorded by, for example, irradiating radiation such as X-rays transmitted through the subject, The grooves 13a, 13b are placed at positions where they engage with the projections 21a, 21b of the excitation / detection means 20, and the sheet 10 engages with the excitation / detection means 20, and the bottom surfaces B of the grooves 13a, 13b and the projections 21a, 21b.
In a state in which the top surface A of b is in contact with the top surface A, it is transported in the arrow Y direction. The conveying speed of the sheet 10 is equal to the moving speed of the belt 40, and the moving speed of the belt 40 is
Input to 0.

On the other hand, the excitation light L emitted from the plurality of laser light sources 23 is condensed on the sheet 10 in a linear shape extending along the arrow X direction by the cylindrical lens 24 provided on the optical path.

The excitation of the linear excitation light L incident on the sheet 10 causes the stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the condensing area of the sheet 10 and its vicinity. . The stimulated emission light M is condensed by the selfoc lens array 26 on the light receiving surface of each photoelectric conversion element 29 constituting the line sensor 28. At this time, the excitation light L slightly reflected on the stimulated emission light M transmitted through the selfoc lens array 26 and reflected on the surface of the sheet 10 is cut by the excitation light cut filter 27.

The stimulated emission light M received by each photoelectric conversion element 29 is photoelectrically converted, and each signal S obtained by the photoelectric conversion is input to the image information reading means 30. Each signal S is processed by the image information reading means 30 in accordance with the position of the sheet 10 based on the moving speed of the scanning belt 40, and is output as image data to an image processing device (not shown).

During the reading of the image information, the sheet 10 and the excitation / detection means 20 are provided with the grooves 13a, 13b and the projections 21.
a and 21b are engaged with each other, that is, the reference surfaces B and A are in contact with each other, so that the distance between the surface of the sheet 10 and the excitation optical system 22 and the detection optical system 25 is kept constant. Can be held. As a result, the excitation light L can be accurately focused on the surface of the sheet 10 to excite the line with a narrow line width, and the stimulating light M carrying image information emitted from the surface of the sheet 10 can be emitted.
Can be accurately imaged on the light receiving surface of the line sensor 28 at a ratio of 1: 1.

The structure of the contact portion between the stimulable phosphor sheet of the present invention and the excitation / detection means of the reader is not limited to the embodiment shown in FIG. 1 and FIG. The structure shown in (1) to (4) may be used.

In FIG. 5A, the stimulable phosphor sheet 5
0 (support 51, frames 52a and 52b, stimulable phosphor layer 5
4) are provided with protrusions 53a and 53b, and the excitation / detection means 60 is provided with corresponding grooves 61a and 61b. The reference surface B of the sheet 50 is the top surface of the projections 53a and 53b, and the reference surface A of the excitation / detection means 60 is the groove 61
a, 61b are bottom surfaces. The reading is performed by the protrusions 53a and 53b of the sheet and the grooves 61a and 61
1b is engaged.

In (2) of FIG. 5, the stimulable phosphor sheet 5
Only the projections 53a and 53b are provided at 0, and the lower part of the excitation / detection means 70 is a plane. In this case, the reference surface B of the sheet is the top surface of the projections 53a and 53b, and the reference surface A of the excitation / detection means 70 is the lower surface. Reading is
The operation is performed in a state where the tops of the projections 53a and 53b of the sheet 50 are in contact with the lower surface of the excitation / detection means 70.

In FIG. 5C, the projections 21a and 21b are provided only on the excitation / detection means 20, and the stimulable phosphor sheet 80 (the support 81 and the stimulable phosphor layer 84) is planar. . The reference plane B of the sheet is the surface of the stimulable phosphor layer 84, and the reference plane A of the excitation / detection means 20 is the protrusions 21a, 2b.
1b is the top surface. The reading is performed in a state where the protrusions 21a and 21b of the excitation / detection unit 20 are in contact with the surface of the sheet 70.

Also in FIG. 5D, projections 21a and 21b are provided only on the excitation / detection means 20, and the stimulable phosphor sheet 90 (here, the support 91, the frames 92a and 92b, the stimulable phosphor) is provided. Layer 94) is planar. However, sheet 90
Is a top surface of the frames 92a and 92b of the support 91, and the reading is performed in a state where the projections 21a and 21b of the excitation / detection means 20 are in contact with the surfaces of the frames 92a and 92b of the sheet 90. Positioning can be performed more accurately by setting the reference surface of the sheet not on the surface of the phosphor layer formed by coating or the like, but on the surface of the support that can be precisely processed.

The tops of the stimulable phosphor sheet and the protrusions of the excitation / detection means and / or the bottoms of the grooves need not necessarily be flat, but may be curved.

Further, the radiation image information reading apparatus of the present invention is not limited to the embodiment shown in FIG. 1, and each of the excitation optical system and the detection optical system can employ various known structures. . For example, in the above description, the number of the detection optical system is one. However, as shown in FIG. 6, a configuration in which two detection optical systems are arranged on both sides may be adopted.

In FIG. 6, the excitation light L emitted from the laser light source 23 is linearly condensed by the cylindrical lens 24 and is incident on the sheet 10 almost perpendicularly. Due to the incidence of the excitation light L, a part of the stimulated emission light M emitted from the light condensing area of the sheet 10 and its vicinity is collected on the light receiving surface of each photoelectric conversion element 29 of the line sensor 28 by the selfoc lens array 26. It is lighted, photoelectrically converted by each photoelectric conversion element 29, and output as a signal S. On the other hand, another part of the stimulated emission light M 'is transmitted to the selfoc lens array 26'.
Is collected on the light receiving surface of each photoelectric conversion element 29 ′ of the line sensor 28 ′, is photoelectrically converted by each photoelectric conversion element 29 ′, and is output as a signal S ′. The signals S and S ′ are subjected to addition processing by image information reading means (not shown), then subjected to arithmetic processing corresponding to the portion of the sheet 10, and output as image data.

As the line light source, the light source itself may be linear, and a fluorescent lamp, a cold cathode fluorescent lamp or the like can be used. Alternatively, the emitted excitation light may be linear, and a broad area laser or the like may be used. The excitation light emitted from the line light source may be one that emits continuously, or may be pulse light that repeats emission and stop. From the viewpoint of noise reduction, it is preferable that the light is a high-output pulse light.

Instead of the SELFOC lens array, a micro lens array can be used. In addition to the CCD sensor, an amorphous silicon sensor, a CCD with a back illuminator, a MOS image sensor, and the like can be used as the line sensor.

In the above embodiment, the optical system between the stimulable phosphor sheet and the line sensor is set to a 1: 1 image forming system for simplicity of description, but an enlargement / reduction optical system is used. May be. However, it is preferable to use a unity or magnifying optical system in order to increase the light collection efficiency. Image processing means for performing various signal processing on the image data signal output from the image information reading means; image output means for outputting and displaying a visible image represented by the image data signal on a CRT or a dry film; It is also possible to adopt a structure further provided with a suction means for pulling out the stimulable phosphor sheet stored in the cassette from the cassette, or an erasing means for appropriately releasing the radiation energy still remaining on the sheet after the reading is completed.

The stimulable phosphor sheet of the present invention shown in FIGS. 2 and 5 can be manufactured, for example, as follows.

As the material of the support, various conventionally known materials can be used, for example, resin materials such as polyethylene terephthalate, polyethylene naphthalate, aramid resin, polyimide resin, metals such as aluminum, ceramics, and quartz. Glass can be mentioned. The support may be filled with a light-reflective material (eg, alumina particles, titanium dioxide particles, barium sulfate particles) for reflecting excitation light or stimulated emission light, or may be provided with voids. . Alternatively, the support may be filled with a light-absorbing material (eg, carbon black) for absorbing excitation light or stimulated emission light.

Using this support material, FIG. 2 or FIG.
A frame-shaped support having grooves or projections as shown in (1) is prepared. The frame portion and the projection portion of the support may be integrally formed with the support base from the beginning by molding the above material, or after forming the base by processing the material into a sheet shape, A frame portion and a protruding portion may be provided thereon by bonding, vapor deposition, coating, or the like. The groove portion of the support may be formed by etching or the like after forming the frame portion. These frames and protrusions
The support base may be formed of a different material, but is preferably the same material in terms of strength and the like.

In a known stimulable phosphor sheet, in order to improve the sensitivity or image quality (sharpness, granularity) as a sheet, a light reflecting layer made of a light reflecting substance such as titanium dioxide or carbon black. It is known to provide a light absorbing layer or the like made of a light absorbing substance. Also for the support used in the present invention, these various layers can be provided inside the frame, and the configuration thereof can be arbitrarily selected according to the purpose, use, etc. of the desired stimulable phosphor sheet. it can. Further, JP-A-58-200
As described in JP-A-200, for the purpose of improving the sharpness of the obtained image, the inner surface of the frame of the support (an undercoat layer (adhesion-imparting layer) on the inner surface of the frame, a light reflecting layer or a light absorbing layer) When an auxiliary layer such as a layer is provided, the surface of the auxiliary layer may be provided).

A stimulable phosphor layer is provided in the frame of the support. The stimulable phosphor has a wavelength of 400 to 90.
Irradiation of excitation light in the range of 0 nm results in 300 to 500 n
A stimulable phosphor that emits stimulable light in the wavelength range of m is preferred. An example of such a stimulable phosphor is described in JP-B-7-845.
No. 88, JP-A-2-193100 and JP-A-4-3
It is described in detail in each publication of No. 10900.

[0055] Among these, the basic formula ^{(I): M I X ·} aM II X '2 · bM III X "3: zA ‥‥ alkali metal halide stimulable phosphor represented by (I) The body is particularly preferred, provided that M ^I represents at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs, and M ^II represents Be, Mg, Ca, Sr, Ba,
At least one alkaline earth metal or divalent metal selected from the group consisting of Ni, Cu, Zn and Cd;
^III is Sc, Y, La, Ce, Pr, Nd, Pm, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b represents at least one rare earth element or trivalent metal selected from the group consisting of Lu, Al, Ga and In, and A represents Y, Ce, Pr, Nd, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu, Na, M
represents at least one rare earth element or metal selected from the group consisting of g, Cu, Ag, Tl and Bi. X, X '
And X ″ each represents at least one halogen selected from the group consisting of F, Cl, Br and I. a,
b and z are respectively 0 ≦ a <0.5, 0 ≦ b <0.
5, represents a numerical value in the range of 0 ≦ z <0.2.

It is preferable that M ^I in the basic composition formula (I) contains at least Cs. It is preferable that X contains at least Br. A is particularly preferably Eu or Bi. In addition, the basic composition formula (I) includes, if necessary, aluminum oxide,
A metal oxide such as silicon dioxide or zirconium oxide may be added as an additive in an amount of 0.5 mol or less based on 1 mol of M ^I.

Further, a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor represented by the basic composition formula (II): M ^II FX: zLnｎ (II) is also preferable. However, M ^II is Ba,
Ln represents at least one kind of alkaline earth metal selected from the group consisting of Sr and Ca, and Ln represents Ce, Pr, Sm, E
represents at least one rare earth element selected from the group consisting of u, Tb, Dy, Ho, Nd, Er, Tm and Yb. X represents at least one halogen selected from the group consisting of Cl, Br and I. z is 0 <z ≦ 0.2
Represents a numerical value within the range.

In the basic composition formula (II), M ^II represents B
It is preferred that a occupies more than half. As Ln,
Particularly, Eu or Ce is preferable. In addition, in the basic composition formula (II), F: X = 1: 1 appears in the notation, which indicates that it has a BaFX type crystal structure, and the stoichiometry of the final composition It does not indicate the composition. In general, a state in which many F ⁺ (X ⁻ ) centers, which are vacancies of X ⁻ ions, are generated in a BaFX crystal,
It is preferable to increase the stimulating efficiency with respect to light of 600 to 700 nm. At this time, F is often slightly more than X.

The stimulable phosphor layer can be formed inside the support in accordance with various known phosphor layer forming methods. For example, the above-described stimulable phosphor or a raw material mixture thereof is formed by a vapor deposition method such as an electron beam evaporation method, and a columnar crystal of the stimulable phosphor grows in a thickness direction substantially as a phosphor layer. Alternatively, a coating solution prepared by dispersing and dissolving the stimulable phosphor particles and the binder in an appropriate organic solvent is formed by coating and drying to form the phosphor particles and the binder dispersingly supporting the phosphor particles. Phosphor layer. The binder can be appropriately selected from various known binder resins and used. Alternatively, the stimulable phosphor layer separately formed as described above may be bonded to the inside of the support with an adhesive or the like.

Further, a protective film may be provided on the surface of the stimulable phosphor layer for the convenience of transport and handling of the stimulable phosphor sheet and to avoid a change in characteristics. The protective film is desirably transparent so that it hardly affects the incidence of excitation light and the emission of stimulated emission light, and the stimulable phosphor sheet is formed from physical impact or chemical influence given from the outside. It is desirable that it be chemically stable, highly moisture-proof and have high physical strength so that it can be sufficiently protected.

As the protective film, a solution prepared by dissolving a transparent organic polymer substance such as a cellulose derivative, polymethyl methacrylate, or an organic solvent-soluble fluororesin in an appropriate solvent is used as the protective film. An organic polymer film such as polyethylene terephthalate or a sheet for forming a protective film such as a transparent glass plate is separately formed by coating on the phosphor layer or using a suitable adhesive on the surface of the phosphor layer. Those provided or those obtained by depositing an inorganic compound on a phosphor layer by vapor deposition or the like are used. The thickness of the protective film is generally in the range of about 0.1 to 20 μm when made of a polymer substance, and in the range of 100 to 1000 μm when made of an inorganic compound such as glass.

Further, a fluororesin coating layer may be provided on the surface of the protective film in order to enhance the contamination resistance of the protective film. The fluororesin coating layer can be formed by applying a fluororesin solution prepared by dissolving (or dispersing) a fluororesin in an organic solvent on the surface of the protective film and drying.
The thickness of the fluororesin coating layer is usually 0.5 μm to 20 μm.
m.

As described above, the stimulable phosphor sheet of the present invention is obtained. The structure of the sheet of the present invention may include various known variations. For example, for the purpose of improving the sharpness of the obtained image, at least one of the above-mentioned layers may be colored with a coloring agent that absorbs excitation light but does not absorb stimulating light (Japanese Patent Publication No. No. 59-23400).

The stimulable phosphor sheet of the present invention has a structure in which the frame of the support is provided not only on the two sides on both sides as shown in FIGS. It may be. Further, a protective film may be provided on the stimulable phosphor layer as described above.

FIG. 7A is a sectional view showing another example of the structure of the stimulable phosphor sheet of the present invention, and FIG. 7B is a top view thereof. In FIG. 7, the stimulable phosphor sheet is
It comprises a support 101, a stimulable phosphor layer 104, and a protective film 105 in order from the bottom. The support body 101 has a frame 102 at a peripheral edge thereof, and linear grooves 103a and 103b are provided on upper portions on both sides of the frame 102, respectively. With such a configuration, the stimulable phosphor layer 104 can be sealed between the support 101 and the protective film 105 and shielded from the external atmosphere, and when the stimulable phosphor is hygroscopic. In this case, the moisture resistance of the sheet can be improved.

[0066]

According to the present invention, a projection or the like is provided on one of the stimulable phosphor sheet and the excitation / detection means of the reader to provide a positioning function, and the top surface of the projection or the like is provided. By performing reading in a state where both are in contact with each other as a reference plane, the distance between the sheet surface and the excitation optical system such as a line light source and the detection optical system such as a line sensor is kept constant regardless of the thickness unevenness of the sheet. be able to. Since the positioning in the depth direction can be accurately performed, a high-speed and high-quality radiation image can be obtained. For this reason, the reading method and apparatus of the present invention are advantageous when used for medical diagnostic radiography, industrial radiography, and fluoroscopy.

[Brief description of the drawings]

FIG. 1A is a configuration diagram showing an example of a radiation image information reading apparatus according to the present invention, and FIG.
FIG. 3 is a front view of the inside, and (3) is a box-shaped excitation / detection unit 20.
It is a side view of an inside.

FIG. 2A is a schematic cross-sectional view showing an example of the structure of a portion where the stimulable phosphor sheet of the present invention and the excitation / detection means of the reader are engaged, and FIG. 2B is a schematic sectional view of FIG. It is a top view.

FIG. 3 is a front view showing an excitation optical system 22.

FIG. 4 is a front view showing a detection optical system 25.

FIG. 5 is a schematic sectional view showing another example of the structure of the contact portion between the stimulable phosphor sheet of the present invention and the excitation / detection means of the reader.

FIG. 6 is a side view showing another example of the configuration of the excitation / detection means.

FIG. 7A is a cross-sectional view showing another example of the configuration of the stimulable phosphor sheet of the present invention, and FIG. 7B is a top view thereof.

[Explanation of symbols]

 Reference Signs List 10 stimulable phosphor sheet 11 support 12a, 12b frame 13a, 13b groove 14 phosphor layer 20 excitation / detection means 21a, 21b protrusion 22 excitation optical system 23 laser light source 24 cylindrical lens 25 detection optical system 26 selfoc lens array 27 Excitation light cut filter 28 Line sensor 29 Photoelectric conversion element 30 Image information reading means 40 Scanning belt L Excitation light M Stimulated light S signal

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H04N 1/04 H04N 1/04 EF term (Reference) 2G083 AA03 BB04 CC04 CC10 DD11 DD17 DD18 EE07 2H013 AC04 AC05 2H108 AA17 CA00 CB01 FA01 FA31 5B047 AA17 AB02 BA01 BB03 BC05 BC07 BC11 BC14 BC18 CA09 5C072 AA01 BA03 BA04 CA06 DA02 EA05 MA05 NA02 VA01

Claims (11)

[Claims] 1. A stimulable phosphor sheet having a support and a stimulable phosphor layer provided thereon, wherein the support is a frame having protrusions on at least both side edges thereof. A stimulable phosphor having a shape in which a linear groove is provided along the frame at the top of the frame, and a stimulable phosphor layer is provided inside the frame; Sheet. 2. The stimulable phosphor sheet according to claim 1, wherein the stimulable phosphor sheet on which the radiation image information is stored is formed by linearly arranging a line light source and a plurality of photoelectric conversion elements. A box-shaped excitation / detection means provided with a line sensor comprising: a linear projection along the edge at both edges substantially orthogonal to the line sensor below the box-type excitation / detection means. On the lower side, the groove of the sheet and the projection of the excitation / detection means are arranged so as to mesh with each other, and while the sheet is moved in the direction of the groove while meshing, the line light source is partially applied to the surface of the sheet. The sheet is linearly irradiated with excitation light emitted from the sheet in a direction substantially orthogonal to the moving direction, and stimulated emission light emitted from the excitation light irradiated portion of the sheet is received one-dimensionally by the line sensor to generate photoelectrically. Performs a conversion, and outputs the output from the line sensor to the Sequentially read according to the movement of the
A radiation image information reading method comprising obtaining radiation image information as an electric image signal. 3. The stimulable phosphor sheet according to claim 1, wherein the stimulable phosphor sheet linearly irradiates a part of the stimulable phosphor sheet on which the radiation image information is stored and recorded with an excitation light;
A box-shaped excitation device comprising: a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to receive one-dimensionally photostimulated emission light emitted from an excitation light irradiation portion of the sheet and perform photoelectric conversion. Exciting / detecting means, wherein the detecting means is provided with linear projections along both edges substantially perpendicular to the lower line sensor, and the sheet is provided with the groove and the exciting / detecting means. Scanning means for moving in the groove direction when the projections are engaged with each other, and reading means for sequentially reading the output from the line sensor in accordance with the movement of the sheet to obtain radiation image information as an electric image signal. Radiation image information reading device. 4. A stimulable phosphor sheet having a support and a stimulable phosphor layer provided thereon, wherein the support is a frame having projections on at least both side edges thereof. A stimulable phosphor having a shape in which linear protrusions are provided along the frame at the top of the frame, and a stimulable phosphor layer is provided inside the frame; Sheet. 5. The stimulable phosphor sheet according to claim 4, wherein the stimulable phosphor sheet on which the radiation image information is stored is formed by linearly arranging a line light source and a plurality of photoelectric conversion elements. Box-type excitation / detection means comprising a line sensor comprising: a linear groove provided along both edges of the box-shaped excitation / detection means, the edges being substantially orthogonal to the lower line sensor. On the lower side, the projections of the sheet and the grooves of the excitation / detection means are arranged so as to mesh with each other, and while the sheet is moved in the direction of the projection while being engaged, the line light source is formed on a part of the surface of the sheet. The sheet is linearly irradiated with excitation light emitted from the sheet in a direction substantially orthogonal to the moving direction, and stimulated emission light emitted from the excitation light irradiated portion of the sheet is received one-dimensionally by the line sensor to generate photoelectrically. Performs a conversion, and outputs the output from the line sensor to the Sequentially read according to the movement of the
A radiation image information reading method comprising obtaining radiation image information as an electric image signal. 6. The stimulable phosphor sheet according to claim 4, wherein the stimulable phosphor sheet linearly irradiates a part of the stimulable phosphor sheet on which the radiation image information is stored and recorded with an excitation light;
A box-shaped excitation device comprising: a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to receive one-dimensionally photostimulated emission light emitted from an excitation light irradiation portion of the sheet and perform photoelectric conversion. Exciting / detecting means, wherein the detecting means is provided with linear grooves along the edges at both edges substantially orthogonal to the lower line sensor; Scanning means for moving in the projection direction in a state where the grooves are engaged with each other, and reading means for sequentially reading the output from the line sensor in accordance with the movement of the sheet to obtain radiation image information as an electric image signal. Radiation image information reading device. 7. The stimulable phosphor sheet according to claim 4, wherein the stimulable phosphor sheet on which the radiation image information is accumulated and recorded comprises a line light source and a plurality of photoelectric conversion elements arranged linearly. The projection of the sheet is arranged below the excitation / detection means under the box-shaped excitation / detection means provided with a line sensor, and the sheet is in contact with the projection / detection means in the projection direction. While moving, a part of the surface of the sheet is linearly irradiated with excitation light emitted from the excitation light source in a direction substantially perpendicular to the moving direction, and the stimulus emitted from the excitation light irradiated portion of the sheet is irradiated. Since the emitted light is one-dimensionally received by the line sensor to perform photoelectric conversion, and the output from the line sensor is sequentially read in accordance with the movement of the sheet to obtain radiation image information as an electric image signal. Radiation image information reading Method. 8. The stimulable phosphor sheet according to claim 4, wherein the stimulable phosphor sheet linearly irradiates a part of the stimulable phosphor sheet on which the radiation image information is stored and recorded with an excitation light;
A box-shaped excitation device comprising: a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to receive one-dimensionally photostimulated emission light emitted from an excitation light irradiation portion of the sheet and perform photoelectric conversion. Detecting means, scanning means for moving the sheet in the direction of the protrusion while the protrusion thereof is in contact with the lower portion of the excitation and detection means, and sequentially reading the output from the line sensor in accordance with the movement of the sheet; A radiation image information reading device having a reading unit for obtaining radiation image information as an electric image signal. 9. A box-shaped excitation / detection means provided with an excitation light source and a line sensor having a plurality of photoelectric conversion elements arranged linearly, wherein the stimulable phosphor sheet on which the radiation image information is stored is recorded. The surface of the sheet and the excitation / detection means are located below the excitation / detection means provided with linear projections along the edges at both edges substantially orthogonal to the lower line sensor. The excitation light emitted from the excitation light source on a part of the surface of the sheet is substantially perpendicular to the moving direction while the sheet is moved in the direction of the projection while the sheet is in contact with the projection. Irradiates linearly in the direction, stimulated emission light emitted from the excitation light irradiated portion of the sheet is one-dimensionally received by the line sensor to perform photoelectric conversion, and outputs from the line sensor are output to the sheet. The radiation image information is read sequentially according to the movement of the A radiographic image information reading method comprising obtaining an electric image signal. 10. A stimulable phosphor sheet having a frame-shaped support having convex portions on at least both side edges and a stimulable phosphor layer provided inside the frame. 10. The radiation image information reading method according to claim 9, wherein the upper part of the frame of the sheet and the projection of the excitation / detection means are arranged to be in contact with each other. 11. A line light source for irradiating a part of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light in a linear manner, and a stimulable luminescence light emitted from the excitation light irradiation part of the sheet is primarily used. A box-shaped excitation / detection means including a line sensor in which a plurality of photoelectric conversion elements are linearly arranged to perform photoelectric conversion by originally receiving light, and is substantially orthogonal to a line sensor below the box-shaped excitation / detection means. Exciting / detecting means provided with linear projections along the edges at both edges thereof, and scanning means for moving the sheet in the frame direction while the surface of the sheet is in contact with the projections of the exciting / detecting means And a reading unit for sequentially reading the output from the line sensor in accordance with the movement of the sheet to obtain radiation image information as an electric image signal.