JP2003195435A - Cassette for radiographing, radiograph reader and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiographing cassette capable of improving the quality of a radiograph by effectively removing scattered light and a radiograph reader and a radiograph reading method using the cassette. <P>SOLUTION: A front plate 11 of the radiographing cassette 10 is provided with a grid 13, and a radiograph stimulated and recorded in a stimulable phosphor sheet 20 is read out as image information on a face opposed to a face irradiated with radiant rays. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image reading technique, and more particularly to a radiation image information reading technique using a stimulable phosphor sheet.

[0002]

2. Description of the Related Art Conventionally, a radiation image represented by an X-ray image has been widely used for disease diagnosis and the like. As a method for obtaining this radiographic image, the radiation transmitted through the subject is applied to a phosphor layer called an intensifying screen, and the visible light emitted from the phosphor layer is irradiated with visible light of the silver halide photographic material (hereinafter, A so-called radiographic method has been proposed and put into practical use, in which a visible image is obtained by irradiating a "photosensitive material") and developing the photosensitive material.

In recent years, instead of the radiographic method described above, the applied radiation energy is accumulated,
A radiation image recording / reproducing system using a “stimulable phosphor” that is stimulated to emit light in response to the stored and recorded radiation energy upon recording and irradiation with excitation light has been proposed.

In this radiation image recording / reproducing system, by irradiating the stimulable phosphor with the radiation transmitted through the subject, the radiation energy (hereinafter referred to as "image information") corresponding to the radiation transmission density of each part of the subject is obtained. After being accumulated and recorded in the stimulable phosphor, the radiation energy recorded and accumulated in the stimulable phosphor by excitation light is stimulated to emit light, and the intensity of this stimulated emission light is converted into an electric signal. The electric signal is reproduced as a visible image through an image recording material such as a photosensitive material or an image display device such as a CRT.

The stimulable phosphor is generally laminated on a sheet-like support and is often handled by being stored in a radiographic cassette. Radiographic cassette (hereinafter,
"Casette" is a flat housing that can store the stimulable phosphor, prevents physical damage to the stimulable phosphor during transportation or during photography, and also prevents stimulable phosphor after photography. It is intended to prevent the stored image information from being erased by being irradiated with light.

A cassette containing a stimulable phosphor sheet composed of a sheet-shaped support and a stimulable phosphor is placed at a predetermined position and used for radiographic image capturing.
When reading the accumulated and recorded image information, the stimulable phosphor sheet taken out from the cassette is scanned with excitation light. As a radiation image reading device that reads image information in this manner, there are devices disclosed in, for example, Japanese Patent Application Laid-Open Nos. 11-160817 and 11-338079.

[0007]

However, according to the radiographic image recording / reproducing system using the stimulable phosphor sheet described above, a radiographic image with a large amount of information can be obtained with a much smaller exposure dose than the radiographic system. However, since the stimulable phosphor sheet has high sensitivity, it also accumulates and records low-energy radiation (scattered rays) scattered when passing through a subject. If the accumulation and recording of accurate image information are hindered by such scattered radiation, various adverse effects such as deterioration of diagnostic performance may occur.

As means for removing such scattered radiation, conventionally, a radiation absorbing layer made of lead or the like having a high radiation absorptivity, aluminum having a low radiation absorptivity, paper,
A "grid" is used in which a laminated body, in which radiation transmission layers made of wood, synthetic resin, etc. are alternately provided, is covered with a cover member having a low radiation absorption rate. Scattered radiation was removed by placing this grid between the phosphor sheets.

However, the members that make up this grid,
Radiation may also be scattered by the grid itself, which may prevent accurate accumulation and recording of image information reaching the stimulable phosphor sheet.

An object of the present invention is to provide a radiographic cassette capable of reducing the influence of scattered radiation and improving the quality of a radiographic image, and a radiographic image reading apparatus and method using the same.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is a radiographic cassette provided with a housing for accommodating a stimulable phosphor sheet, the back surface of the front plate of the housing. Further, a scattered radiation removing grid is attached to, and the stimulable phosphor sheet is provided in contact with the scattered radiation removing grid.

According to the first aspect of the present invention, the grid for removing scattered low-energy radiation (scattered rays) generated during radiography is attached to the back of the front plate of the radiography cassette. In addition to preventing the accumulation and recording of image information based on scattered radiation in the stimulable phosphor sheet, the grid and the stimulable phosphor sheet are in contact with each other, so that there is less scattering of scattered radiation in the grid itself. By storing and recording the image information based on the radiation in the stimulable phosphor sheet, more accurate image information can be stored and recorded.

According to a second aspect of the present invention, in a radiographic cassette equipped with a housing for accommodating a stimulable phosphor sheet, the front plate of the housing is formed of a scattered radiation removing grid, and the front plate of the front plate is The photostimulable phosphor sheet is provided in contact with the back surface of the phosphor sheet.

According to the second aspect of the present invention, since the front plate of the radiographic cassette itself is a grid, there are fewer scattered radiation generation factors and less scattered radiation generation. Further, the generated scattered rays are removed by the grid, and since the grid and the stimulable phosphor sheet are in contact with each other, the radiation-based image information is bright at the stage where the scattered rays generated by the grid itself are less scattered. Since it is stored and recorded in the exhaustive phosphor sheet, more accurate image information can be stored and recorded.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the radiographic cassette according to the item (1), the housing is
The housing main body having an opening and the front plate that covers the opening, the stimulable phosphor sheet is in close contact with the scattered radiation removal grid, from the housing main body together with the front plate. It is characterized by being separated.

According to the third aspect of the present invention, the stimulable phosphor sheet is separated from the housing main body together with the front plate in a state of being in close contact with the grid, so that the grid can support the stimulable phosphor sheet. Thus, when the stimulable phosphor sheet after radiography is handled outside the radiographic cassette, damage such as bending of the stimulable phosphor sheet can be prevented.

A fourth aspect of the present invention is a radiographic image reading apparatus using the radiographic cassette according to any of the first to third aspects, wherein the stimulable phosphor sheet comprises:
Irradiation means for irradiating the surface opposite to the surface irradiated with the irradiation of excitation light, and by detecting the stimulable light generated based on the excitation light irradiated by the irradiation means, the stimulable phosphor sheet And a reading unit for reading the radiation image.

According to the fourth aspect of the present invention, the image information stored and recorded in the stimulable phosphor sheet, which is arranged in the grid and is less affected by scattered radiation, is recorded in the stimulable phosphor sheet. On the side opposite to the side where the
Image information can be read.

According to a fifth aspect of the present invention, in the radiographic image reading apparatus according to the fourth aspect, there is provided a stimulable phosphor sheet take-out means for taking out the stimulable phosphor sheet from the radiographic cassette. Characterize.

According to the fifth aspect of the present invention, the stimulable phosphor sheet arranged on the grid in the cassette for radiography can be taken out, so that the stimulable phosphor sheet after radiography can be obtained. It can be handled outside the radiographic cassette, and various methods can be used for reading image information.

The invention according to claim 6 is the invention according to claim 4 or 5.
The radiation image reading method in the radiation image reading apparatus according to claim 1, wherein the stimulable phosphor sheet is irradiated with excitation light on a surface opposite to a surface irradiated with radiation on which a radiation image is recorded, and the excitation is performed. It is characterized in that the radiation image is read from the stimulable phosphor sheet by detecting stimulating light generated based on light.

According to the sixth aspect of the invention, the image information stored and recorded in the stimulable phosphor sheet, which is arranged in the grid and is less affected by scattered radiation, is used as the stimulable phosphor sheet. On the side opposite to the side where the
Image information can be read.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

[First Embodiment] As shown in FIG. 1, a cassette 10 according to the present embodiment has a rectangular planar shape, and a front plate 11 is a cassette case 12 serving as a housing body. It is attached so that it can be separated. In addition, as shown in FIG. 2, the cassette 10 includes a front plate 11, a grid 13, a stimulable phosphor sheet 20, and a cassette case 12. The cassette 10 protects the stimulable phosphor sheet 20 during shooting and during transportation, and also prevents the image information accumulated by irradiation of the stimulable phosphor sheet 20 after shooting from being erased. It is a thing.

A grid 13 is attached to the back surface of the front plate 11, and a stimulable phosphor sheet 20 is placed in contact with the back surface of the grid 13. This front plate 11
Is attached so as to cover the storage portion 12x of the cassette case 12, and serves as a light-shielding plate that prevents the accumulated image information from being erased by irradiating the photostimulable phosphor sheet 20 with light after photographing. It also functions. In this embodiment, a guide groove 11 ′ is provided on the side surface of the front plate 11,
Protrusions 12 'corresponding to the guide grooves 11' are provided on the inner side surface of the cassette case 12 so that the front plate 11 slides with respect to the cassette case 12 (see FIGS. 1 and 2). .

For X-ray photography, the front plate 11 is mounted on the cassette case 12, the stimulable phosphor sheet 20 is housed in the housing 12x thereof, and then the subject 50, the front plate 11, and the grid 13 are made transparent. The X-ray is irradiated onto the stimulable phosphor sheet 20 (see FIG. 2A). For this reason,
The front plate 11 is made of a material having a high X-ray transmittance. Further, the thickness of the front plate 11 is preferably about 1 to 5 mm so as not to hinder the transmission of X-rays.

The front plate 11 is preferably made of a highly rigid material for the purpose of preventing physical damage to the stimulable phosphor sheet 20. Thus, as a material having high X-ray transmittance and high rigidity, aluminum,
Examples thereof include carbon fiber reinforced resin, acrylic resin, phenol resin, polyimide resin, and composite materials of these resins and aluminum. In the present embodiment, carbon fiber reinforced resin is used as the material of front plate 11.

The cassette case 12 is provided with a storage portion 12x for storing the stimulable phosphor sheet 20 to prevent the stimulable phosphor sheet 20 from being damaged at the time of photographing or during transportation, and at the same time, to prevent the stimulable phosphor sheet 20 after photographing. It is intended to prevent the stored and recorded image information from being erased by irradiating the luminescent phosphor sheet 20 with light. The material of the cassette case 12 may be any material as long as it has rigidity enough to prevent physical damage to the stimulable phosphor sheet 20, and various metals, synthetic resins, fiber reinforced resins and the like can be mentioned. .

The grid 13 is used as a means for removing low-energy radiation (scattered rays) scattered when passing through an object such as a subject. The grid 13 includes, for example, as shown in FIG. 3, a radiation absorption layer 13a made of lead having a high radiation absorption rate and a radiation transmission layer 13b made of aluminum, paper, wood, a synthetic resin or the like having a low radiation absorption rate. The alternately provided laminated body is covered with a cover member 13c having a low radiation absorption rate. Grid 1
3 of the radiation that is going to pass through (radiation transmitting layer 1
Since the straight-ahead component (which can pass through 3b) is easily transmitted and the scattered radiation is difficult to be transmitted, the scattered radiation is removed as a result.

The stimulable phosphor sheet 20 is formed by laminating a stimulable phosphor 22 on a sheet-like support 21. The stimulable phosphor 22 accumulates and records the irradiated X-ray energy, and emits stimulated emission according to the accumulated and recorded X-ray energy when irradiated with excitation light.

As the stimulable phosphor 22, US Pat.
Rare earth-activated strontium sulfide-based or rare-earth-activated lanthanum oxysulfide-based phosphors described in US Pat. No. 55-12144, a rare earth activated lanthanum oxyhalide phosphor, disclosed in JP-A-5-55
Examples thereof include copper and / or lead activated zinc sulfide-based, rare earth activated alumina-barium oxide-based or silica-alkaline earth metal-based phosphors described in JP-A-5-12142.

The stimulable phosphor sheet 20 in the present embodiment is provided with a front plate 11 by a fixing means (not shown).
The cassette case 12 is attached to the (grid 13), and the cassette case 12 is stored in the storage portion 12x or taken out in accordance with the sliding movement of the front plate 11 (see FIGS. 1 and 2). The thickness of the stimulable phosphor sheet 20 depends on the accumulated X-ray dose, the type of the stimulable phosphor, and the storage portion 12x of the cassette case 12.
It can be appropriately determined according to the height of the.

Next, a radiation image reading apparatus and method using the cassette 10 of the first embodiment will be described. FIG. 4 shows a main configuration of the radiation image reading apparatus 100 according to the present embodiment, which is stored in the stimulable phosphor sheet 20 housed in the cassette 10,
This is a device for reading recorded image information.

As shown in FIG. 4, the radiation image reading apparatus 100 includes a cassette housing portion 100a, an image reading portion 100b, an excitation light source 14 as an irradiation means, and a light guiding means 1.
5, a photoelectric conversion unit 16, an image processing unit 17, an image output unit 18, an erasing unit 19 and the like. The radiation image reading apparatus 100 conveys the front plate 11 from the cassette 10 accommodated in the cassette accommodating portion 100a to the image reading portion 100b by a conveying means (not shown), and then,
After reading the image information from the stimulable phosphor sheet 20 provided on the front plate 11, the front plate 11 is returned to the cassette case 12. The excitation light source 14, the light guide unit 15, and the photoelectric conversion unit 16 are arranged on the side of the stimulable phosphor sheet 20 attached to the front plate 11, and particularly, the excitation light source 14, the light guide unit 15, and the photoelectric conversion unit 16 are arranged. Constitutes a reading means for reading the stimulated emission light from the back surface side (the side opposite to the X-ray irradiation side) of the stimulable phosphor sheet 20.

The cassette housing section 100a and the image reading section 100b protect various devices mounted therein, and after the photographing, the photostimulable phosphor sheet 20 is irradiated with light and accumulated and recorded image information disappears. It is preferable to manufacture it with a material having relatively high rigidity so that various devices mounted therein can be surely protected.

The excitation light source 14 is a stimulable phosphor sheet 20.
By irradiating with excitation light, it has a function of emitting stimulated emission light according to image information stored and recorded. The excitation light source 14 in the present embodiment can irradiate excitation light to the stimulable phosphor sheet 20 while reciprocating in the direction of the arrow in FIG. 4 by a drive mechanism (not shown).

The light guide means 15 is a stimulable phosphor sheet 20.
The stimulated emission light emitted from the device functions so as to be guided to the photoelectric conversion means 16, and is made of a transparent acrylic plate. The light guide means 15 reciprocates in synchronization with the excitation light source 14. The photoelectric conversion means 16 detects the stimulated emission light emitted from the stimulable phosphor sheet 20 and generates an electric signal according to the amount of this stimulated emission light. In this embodiment, a photomultiplier is used as the photoelectric conversion means 16.

The image processing means 17 obtains a digital image signal by A / D converting the image information converted into an electric signal by the photoelectric conversion means 16. The image output means 18 outputs the digital image signal obtained by the image processing means 17 as an X-ray image. Examples of the image output unit 18 include a device for displaying an X-ray image such as a CRT or a liquid crystal display, and a device for hard-copying an X-ray image such as an inkjet printer. The erasing means 19 reads the image information from the stimulable phosphor sheet 20 by the reading means composed of the excitation light source 14, the light guide means 15, and the photoelectric conversion means 16, and then, the inside of the stimulable phosphor sheet 20 is read. The residual radiation energy is released to erase the image information. This erasing means 19 allows the stimulable phosphor sheet 20 to be newly X-ray photographed.

In the radiographic image reading apparatus 100 having such a structure, X-ray photography using the cassette 10 allows the object 50, the front plate 11 and the grid 13 to pass therethrough, and allows the stimulable phosphor sheet 20 to accumulate and record. The read image information can be read.

Further, as described above, the stimulable phosphor sheet 2 is used.
More accurate image information can be obtained by reading the image information on the surface opposite to the surface irradiated with the radiation 0. This is because there is a difference in the image information that is stored and recorded due to the energy difference of the radiation components. The direct component of the image information in the radiation is straight and relatively high energy radiation. On the other hand, the scattered radiation emitted when the radiation collides with the object is radiation of relatively low energy, and the image information is scattered and disturbed. Moreover, by disposing the grid 13, the energy of the scattered radiation is further reduced. Storing and recording the image information on the stimulable phosphor sheet 20 means that the energy of the radiation is absorbed by the stimulable phosphor sheet 20, so that the high-energy straight-through radiation is bright. The back side of the exhaustive phosphor sheet 20 can be reached, and image information can be accumulated and recorded on the back side. On the other hand, low-energy scattered radiation can accumulate and record image information on the front side of the stimulable phosphor sheet 20, but the energy is absorbed before reaching the back side, and few components reach the back side. Therefore, since the image information on the back side is information having many direct components of image information (small scattered rays), more accurate image information can be acquired. Although the front plate 11 is provided with the grid 13 in the first embodiment, the front plate 1
The configuration may be such that the grid 1 itself is formed. According to such a configuration, the grid 1 is attached to the front plate 11.
It is possible to obtain the same effect without needing to provide 3.

[Second Embodiment] As shown in FIG. 5, a cassette 10a according to the present embodiment has a rectangular planar shape, and a grid 1 as a front plate.
3 is fixed to the cassette case 12a as the main body of the housing. Further, as shown in FIG. 6, the cassette 10a is
Grid 13 as front plate, stimulable phosphor sheet 2
0, a protective film 23, and a cassette case 12a. The cassette 10a protects the stimulable phosphor sheet 20 during photographing and during transportation, and prevents the image information accumulated by irradiating the stimulable phosphor sheet 20 after photographing from disappearing. It is a thing.

The grid 13 as a front plate is provided with a stimulable phosphor sheet 20 and is attached so as to cover the storage portion 12x of the cassette case 12a, and the photostimulable phosphor sheet 20 is exposed to light after photographing. It also functions as a light shield plate that prevents the accumulated image information from being erased by being irradiated. In the present embodiment, the grid 13 as the front plate and the cassette case 12a are fixed and have an integrated structure (see FIGS. 5 and 6).

The X-ray imaging is the same as that of the first embodiment, and the explanation is omitted.

The cassette case 12a is provided with a storage portion 12x for storing the photostimulable phosphor sheet 20 to prevent the photostimulable phosphor sheet 20 from being damaged at the time of photographing or during transportation, and at the same time after the photographing. It is intended to prevent the stored and recorded image information from being erased by irradiating the luminescent phosphor sheet 20 with light. Further, the cassette case 12a is provided with a rotating shaft 12y and a lid portion 12z attached to the rotating shaft 12y and capable of rotating around the rotating shaft 12y and opening and closing.

The lid portion 12z is used when the stimulable phosphor sheet 20 is taken out from the cassette case 12a when the image information accumulated and recorded in the stimulable phosphor sheet 20 is read in the radiation image reading apparatus. It is opened. 5 and 6, the rotating shaft 12y is provided in the approximate center of the cassette case 12a, but at a location where an opening area where the photostimulable phosphor sheet 20 can be taken out from the cassette case 12a can be secured. It is not particularly limited as long as it is, and depending on the place where the rotation shaft 12y is provided,
The size of the lid 12z changes. Since the material of the cassette case 12a is the same as that of the cassette case 12, the description will be omitted.

The grid 13 is the same as that of the first embodiment, so the description is omitted. The stimulable phosphor sheet 20 (sheet-shaped support 21, stimulable phosphor 22) is provided with a light-transmitting protective film 23 on the surface of the stimulable phosphor 22. Deterioration of the body 22,
Prevent damage. The sheet-shaped support 21 and the protective film 23 in the second embodiment are made of a material having flexibility, such as PET.

The stimulable phosphor sheet 20 in the present embodiment is attached to the grid 13 as a front plate by a fixing means (not shown) and is housed in the housing portion 12x of the cassette case 12a (FIG. 6). reference). The thickness of the stimulable phosphor sheet 20 can be appropriately determined according to the accumulated X-ray dose, the type of the stimulable phosphor, the height of the housing portion 12x of the cassette case 12a, and the like.

Next, the cassette 10a according to the second embodiment.
A radiation image reading apparatus and method using the above will be described. FIG. 7 shows a main configuration of the radiation image reading apparatus 200 according to the present embodiment, in which image information accumulated and recorded in the photostimulable phosphor sheet 20 housed in the cassette 10a is displayed. It is a reading device.

As shown in FIG. 7, the radiation image reading apparatus 200 includes an apparatus housing 200a and a cassette inserting section 200.
b, excitation light source 14, light guide means 15, photoelectric conversion means 16,
Image processing means 17, image output means 18, erasing means 19,
The photostimulable phosphor sheet take-out unit 30, the photostimulable phosphor sheet conveying unit 31, the photostimulable phosphor sheet storage unit 32, and the like are provided. In the radiation image reading device 200, the lid 12z of the cassette 10a inserted into the cassette insertion portion 200b of the device housing 200a has an opening, and the stimulable fluorescent substance taken out by the stimulable phosphor sheet taking-out means 30 from the opening. The body sheet 20 is for reading image information by the reading means (excitation light source 14, light guide means 15, photoelectric conversion means 16) in the conveyance path conveyed by the stimulable phosphor sheet conveyance means 31. The excitation light source 14, the light guide unit 15, and the photoelectric conversion unit 16 are arranged on the back surface side (the side opposite to the X-ray irradiation side) of the stimulable phosphor sheet 20 conveyed to the stimulable phosphor sheet conveying unit 31. These constitute the reading means for reading the stimulated emission light from the back surface side of the stimulable phosphor sheet 20.

The device housing 200a protects various devices mounted therein and prevents the photostimulable phosphor sheet 20 after photographing from being irradiated with light and accumulated and recorded image information being erased. However, it is preferable to manufacture it with a material having relatively high rigidity so that various devices mounted therein can be surely protected. Cassette insertion part 200b
Opens when the cassette 10a is inserted. At the time of opening, the opening is brought into close contact with the cassette 10a, so that light does not enter the inside of the device housing 200a.

The excitation light source 14, the light guide means 15, and the photoelectric conversion means 16 are different from those of the first embodiment only in that they are not moved by the driving mechanism, but other functions are the same, and the description thereof will be omitted. Further, the image processing means 17 and the image output means 18 are the same as those in the first embodiment, and therefore their explanations are omitted.

The stimulable phosphor sheet take-out means 30 is
For example, the stimulable phosphor sheet 20 is taken out of the cassette 10a by a suction cup and guided to the stimulable phosphor sheet conveying means 31. The stimulable phosphor sheet conveying means 31 reads, for example, image information by the reading means (excitation light source 14, light guiding means 15, photoelectric conversion means 16) of the stimulable phosphor sheet 20 by a pair of upper and lower guide rolls. It is to be transported to a position. Sheet-shaped support 21 of stimulable phosphor sheet 20, and protective film 23
Is made of a flexible material, and therefore the stimulable phosphor sheet 20 is transported not only in the straight transport path but also in the arc-shaped transport path when being transported by the guide rolls. be able to. Further, the erasing means 19 causes the erasing means 19 to release the radiation energy remaining in the stimulable phosphor sheet 20, and the image information is erased. This erasing means 19
Thus, the stimulable phosphor sheet 20 is brought into a state in which new X-ray imaging can be performed, and is then conveyed to the stimulable phosphor sheet storage section 32. The stimulable phosphor sheet storage unit 32 stores the stimulable phosphor sheet 20 having read the image information. The stored stimulable phosphor sheet 20 is taken out by a predetermined method.

In the radiographic image reading apparatus 200 having such a structure, the X-ray photography using the cassette 10a
It is possible to read the image information transmitted through the subject 50 and the grid 13 and accumulated and recorded in the stimulable phosphor sheet 20. Further, as in the first embodiment, more accurate image information can be obtained by reading the image information on the surface opposite to the surface on which the stimulable phosphor sheet 20 is irradiated with radiation.

Further, the cassette 10a of the second embodiment
A modified example of the radiation image reading apparatus using will be described. FIG. 8 shows a main configuration of a radiographic image reading apparatus 200 ′ according to the present embodiment, in which the stimulable phosphor sheet 20 stored in the cassette 10a is taken out, and the stimulable phosphor sheet is taken out. After reading the image information stored and recorded in the storage unit 20, the device returns the stimulable phosphor sheet 20 to the cassette 10a.

The radiation image reading apparatus 200 'is shown in FIG.
As shown in FIG. 2, the device housing 200′a, the cassette insertion portion 2
00'b, excitation light source 14, light guiding means 15, photoelectric conversion means 16, image processing means 17, image output means 18, erasing means 19, stimulable phosphor sheet take-out means 30, stimulable phosphor sheet conveying means. 31 and so on.

The radiation image reading apparatus 200 'is different from the radiation image reading apparatus 200 only in the conveying route of the stimulable phosphor sheet 20 and the like, and other functions are the same, and therefore only different portions will be described. To do.

The stimulable phosphor sheet 20 taken out of the cassette 10a by the stimulable phosphor sheet take-out means 30 is read by the stimulable phosphor sheet conveying means 31 (reading means (excitation light source 14, light guide). It is conveyed to the position of the means 15 and the photoelectric conversion means 16) and the image information is read. Since the sheet-shaped support 21 of the stimulable phosphor sheet 20 and the protective film 23 are made of a flexible material, when they are conveyed by the guide rolls, not only the straight traveling path but also an arc-shaped curve. The stimulable phosphor sheet 20 can be conveyed even in the carrying path. The stimulable phosphor sheet 20 after the image information is read is erased by the erasable means 19 provided in the carrying path for returning to the cassette 10a by the stimulable phosphor sheet conveying means 31. Radiation energy remaining inside is released and the image information is erased. This erasing means 19 makes the stimulable phosphor sheet 20 ready for new X-ray photography, and then the stimulable phosphor sheet conveying means 31.
Is returned to the inside of the cassette 10a. Even with the radiation image reading device 200 ′ having such a configuration, the same operational effects as the radiation image reading device 200 can be obtained. In addition, in the second embodiment, the grid 13 is provided as the front plate, but the front plate may be separately provided on the outer surface of the grid 13. With such a configuration, the cassette 10a can be reinforced by the front plate, and the same operational effect can be obtained. When the stimulable phosphor 22 is not deteriorated or damaged, or when deterioration or damage is not a problem,
The protective film 23 is unnecessary and may not be provided.

[Third Embodiment] As shown in FIG. 9, a cassette 10b according to the present embodiment has a rectangular planar shape, and a slide plate 40 is separable from the cassette case 12b. It is joined. Also, FIG.
As shown in FIG. 0, the cassette 10b includes a front plate 11b, a grid 13, a stimulable phosphor sheet 20, and a slide plate 4.
0, a cassette case 12b is provided. The cassette 10b protects the stimulable phosphor sheet 20 during photographing and transportation, and prevents the image information accumulated by the irradiation of the stimulable phosphor sheet 20 after photographing from being erased. It is a thing.

A grid 13 is attached to the back surface of the front plate 11b. The front plate 11b is a cassette case 12.
It is attached so as to cover the storage portion 12x of b, and functions as a light-shielding plate that prevents the accumulated image information from being erased by irradiating the photostimulable phosphor sheet 20 with light after photographing. Also fulfills.

The X-ray imaging is the same as that of the first embodiment, and the explanation is omitted. Also, the front plate 11b
Since the material and the like are similar to those of the front plate 11, the description thereof will be omitted.

The cassette case 12b is the same as the cassette case 12 except that the shape thereof is different, and the description thereof will be omitted. Further, the grid 13 is the same as that of the first embodiment, and therefore its explanation is omitted.

The slide plate 40 is formed of a resin having a light transmitting property, and the stimulable phosphor sheet 20 is attached to the surface side (X-ray irradiation side) thereof. In the present embodiment, by sliding the side end portion 40 ′ of the slide plate 40 into the guide groove 12′b corresponding to the thickness of the side end portion 40 ′ on the inside of the side surface of the cassette case 12, the slide is performed. The plate 40 is structured to slide with respect to the cassette case 12b (see FIGS. 9 and 10).

Since the stimulable phosphor sheet 20 (sheet-like support 21, stimulable phosphor 22) is the same as that in the first embodiment, its explanation is omitted.

The photostimulable phosphor sheet 20 in the present embodiment is provided with a slide plate 4 by a fixing means (not shown).
The cassette case 12b is housed in and taken out of the housing portion 12x as the slide plate 40 slides (see FIGS. 9 and 10). At this time, since the grid 13 and the stimulable phosphor sheet 20 are in close contact with each other, friction may occur between the grid 13 and the stimulable phosphor sheet 20 during the sliding operation. Therefore, it is preferable to protect the stimulable phosphor sheet 20 by covering it with a protective film (not shown). The protection prevents the photostimulable phosphor sheet 20 from being scratched due to friction, and prevents deterioration of image information due to the scratch. The thickness of the stimulable phosphor sheet 20 can be appropriately determined according to the accumulated X-ray dose, the type of the stimulable phosphor, the height of the storage portion 12x of the cassette case 12b, and the like.

Next, the cassette 10b according to the third embodiment.
A radiation image reading apparatus and method using the above will be described. FIG. 11 shows a main configuration of a radiation image reading apparatus 300 according to the present embodiment, which shows image information accumulated and recorded in the stimulable phosphor sheet 20 housed in the cassette 10b. It is a reading device.

The radiation image reading apparatus 300 is shown in FIG.
As shown in FIG. 3, the cassette storage unit 300a, the image reading unit 300b, the excitation light source 14, the light guide unit 15, the photoelectric conversion unit 16, the image processing unit 17, the image output unit 18, the erasing unit 19, and the like are provided. The radiation image reading apparatus 300 includes a slide plate 4 from a cassette 10b housed in a cassette housing unit 300a by a transporting means (not shown).
0 is conveyed to the image reading unit 300b, then image information is read from the photostimulable phosphor sheet 20 provided on the slide plate 40, and then the slide plate 40 is returned to the cassette case 12b. is there. Excitation light source 1
4, the light guide means 15, and the photoelectric conversion means 16 are slide plates 4
They are arranged on the 0 side and constitute a reading means for reading the stimulated emission light from the back surface side (the side opposite to the X-ray irradiation side) of the stimulable phosphor sheet 20.

In this radiation image reading apparatus 300, the first embodiment (radiation image) is performed except that the slide plate 40 is carried from the cassette 10b to the image reading section 300b by a carrying means (not shown) to read the image information. The description is omitted because it is similar to the reading device 100).

By the radiographic image reading apparatus 300 having such a configuration, the object 50, the front plate 11b, and the grid 1 are obtained by X-ray photography using the cassette 10b.
It is possible to read the image information that has been transmitted through No. 3 and accumulated and recorded in the stimulable phosphor sheet 20. In particular, since the slide plate 40 has a light-transmitting property, the image information accumulated and recorded in the stimulable phosphor sheet 20 can be read through the slide plate 40. Further, as in the first embodiment, more accurate image information can be obtained by reading the image information on the surface opposite to the surface on which the stimulable phosphor sheet 20 is irradiated with radiation. The slide plate 40 also functions as a protective plate that protects the stimulable phosphor 22 of the stimulable phosphor sheet 20.

As described above, in the stimulable phosphor sheet 20 provided in contact with the grid 13 in the cassette,
A stimulable phosphor sheet 20 is provided with the accumulated and recorded radiation images.
When reading from, the more accurate image information can be obtained by reading the image information on the surface opposite to the surface on which the stimulable phosphor sheet 20 is irradiated with radiation.

In the above embodiments, the front plates 11 and 11b are made of carbon fiber reinforced resin, but the present invention is not limited to this.
It may be manufactured by a grid, or a front plate may be provided on the front surface of the grid 13 of the cassette 10a. Further, the front plate 11 is detachable by a sliding operation, but the present invention is not limited to this, and any attaching / detaching mechanism using a sandwiching means, a fitting means, or the like may be used. Further, the radiation image reading apparatus may have any configuration, and it is needless to say that the specific detailed structure and the like can be appropriately changed.

[0071]

According to the first aspect of the present invention, scattered low-energy radiation (scattered rays) generated during radiation imaging.
Since the grid for removing the image is attached to the back of the front plate of the radiographic cassette, it prevents the image information based on the scattered rays from being accumulated and recorded in the photostimulable phosphor sheet, and it also prevents Since the stimulable phosphor sheet is in contact with the stimulable phosphor sheet, image information based on radiation is accumulated and recorded in the stimulable phosphor sheet at a stage where scattering of scattered rays generated in the grid itself is less, thereby providing more accurate image information. Can be accumulated and recorded.

According to the second aspect of the present invention, since the front plate itself of the radiation imaging cassette is a grid, the factor of generating scattered rays is smaller, and the generation of scattered rays is smaller. Further, the generated scattered rays are removed by the grid, and since the grid and the stimulable phosphor sheet are in contact with each other, the radiation-based image information is bright at the stage where the scattered rays generated by the grid itself are less scattered. Since it is stored and recorded in the exhaustive phosphor sheet, more accurate image information can be stored and recorded.

According to the invention of claim 3, the stimulable phosphor sheet is separated from the housing main body together with the front plate in a state of being in close contact with the grid, so that the grid can support the stimulable phosphor sheet. Thus, when the stimulable phosphor sheet after radiography is handled outside the radiographic cassette, damage such as bending of the stimulable phosphor sheet can be prevented.

According to the invention described in claim 4, the image information stored in the stimulable phosphor sheet, which is arranged in the grid and is less affected by scattered radiation, is recorded, and the image information is recorded in the stimulable phosphor sheet. On the side opposite to the side where the
Image information can be read.

According to the invention of claim 5, the stimulable phosphor sheet arranged on the grid in the cassette for radiography can be taken out, so that the stimulable phosphor sheet after radiography is obtained. It can be handled outside the radiographic cassette, and various methods can be used for reading image information.

According to the invention of claim 6, the image information stored and recorded in the stimulable phosphor sheet, which is arranged in the grid and is less affected by scattered radiation, is used as the stimulable phosphor sheet. On the side opposite to the side where the
Image information can be read.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a cassette according to a first exemplary embodiment of the present invention.

2A is a sectional view taken along line AA in FIG. 1, and FIG. 2B is FIG.
2B is an enlarged view of a 2B portion of FIG.

FIG. 3 is an enlarged cross-sectional view of the grit according to the embodiment of the present invention.

FIG. 4A is a schematic view of a radiation image reading apparatus according to the first embodiment of the present invention, and FIG. 4B is a view 4B of FIG. 4A.
It is an enlarged view of a part.

FIG. 5 is a schematic perspective view of a cassette according to a second exemplary embodiment of the present invention.

6A is a sectional view taken along line BB of FIG. 5, and FIG.
FIG. 6B is an enlarged view of a portion 6B of FIG.

FIG. 7A is a schematic view of a radiation image reading apparatus according to a second embodiment of the present invention, and FIG. 7B is a view 7B of FIG. 7A.
It is an enlarged view of a part.

FIG. 8A is a schematic view of a modified example of the radiation image reading apparatus according to the second embodiment of the present invention, and FIG. 8B is an enlarged view of a portion 8B of FIG. 8A.

FIG. 9 is a schematic perspective view of a cassette according to a third exemplary embodiment of the present invention.

10A is a sectional view taken along line CC of FIG. 9, and FIG. 10B is an enlarged view of a portion 10B in FIG.

FIG. 11A is a schematic view of a radiation image reading apparatus according to a third embodiment of the present invention, and FIG. 11B is a view of 1 of FIG.
It is an enlarged view of 1B part.

[Explanation of symbols]

10 cassette 11 front plate 12 cassette case (housing main body) 13 grid 14 excitation light source (irradiation means, reading means) 15 light guiding means (reading means) 16 photoelectric conversion means (reading means) 17 image processing means 18 image output means 19 erasing Means 20 Photostimulable phosphor sheet 21 Sheet-like support 22 Photostimulable phosphor 23 Protective film 30 Photostimulable phosphor sheet take-out means 31 Photostimulable phosphor sheet conveying means 32 Photostimulable phosphor sheet storage 40 Slide plate 50 Subjects 100, 200, 200 ', 300 Radiation image reading device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G21K 4/00 A61B 6/00 303K H04N 1/04 H04N 1/04 EF term (reference) 2G083 AA03 BB02 BB03 BB04 CC10 EE02 2H013 AC03 AC04 AC11 BA02 4C093 AA03 AA28 CA07 EB05 EB24 5C072 AA01 BA17 CA06 DA21 DA30 EA02 VA01

Claims (6)

[Claims] 1. A radiographic cassette comprising a housing for accommodating a stimulable phosphor sheet, wherein a scattered radiation removing grid is attached to a back surface of a front plate of the housing, and the scattered radiation removing grid is provided with the bright radiation. A radiographic cassette characterized in that it is provided with a stimulable phosphor sheet in contact therewith. 2. A radiographic cassette comprising a housing for accommodating a stimulable phosphor sheet, wherein a front plate of the housing is formed by a scattered radiation removing grid, and the stimulable surface is formed on the back surface of the front plate. A radiographic cassette comprising a phosphor sheet in contact therewith. 3. The radiographic cassette according to claim 1, wherein the housing is composed of a housing body having an opening and the front plate covering the opening, and the photostimulable phosphor. The sheet is in close contact with the scattered radiation removing grid, and is separated from the housing main body together with the front plate, wherein the sheet is a radiographic cassette. 4. A radiation image reading apparatus using the cassette for radiography according to claim 1, wherein a surface of the stimulable phosphor sheet opposite to a surface irradiated with radiation. Irradiating means for irradiating with excitation light, and a reading means for reading the radiation image from the stimulable phosphor sheet by detecting stimulable light generated based on the excitation light irradiated by the irradiating means, A radiation image reading apparatus comprising: 5. The radiographic image reading apparatus according to claim 4, further comprising a photostimulable phosphor sheet take-out means for taking out the photostimulable phosphor sheet from the radiographic cassette. apparatus. 6. A radiation image reading method in a radiation image reading apparatus according to claim 4, wherein the radiation image-recording surface of the stimulable phosphor sheet is opposite to the radiation-irradiated surface. A radiation image reading method comprising: irradiating a surface with excitation light, and detecting the stimulating light generated based on the excitation light to read the radiation image from the stimulable phosphor sheet.