JPH06308299A - Radiation photographing cassette and radiation image reader - Google Patents

Abstract

PURPOSE:To make a cassette adaptable to the photographing with a device and the photographing separately from the device by providing an openable slide cover on the cassette, and providing an accumulated phosphor layer fixed inside and spread along the cover. CONSTITUTION:An accumulated phosphor plate 3-1 is fixed inside a cassette 2-1, a cassette cover 2-2 openable to the right and left is provided, and a black box is formed when the cover 2-2 is closed. An image reader is provided with a radioactive ray radiation surface 6-2, and the cover 2-2 is manually or automatically drawn to the outside of the device when the cassette 2-1 is loaded from a cassette loading port. Radioactive rays are radiated to the cassette 2-1 for radiation photography, then an excitation light main scanning section 7-4 reads the image information accumulated and recorded on the phosphor plate 3-1 while being moved downward. When the reading action is completed, the halogen lamp of an eraser 7-7 is lighted, and it erases the image information remaining on the phosphor plate 3-1 while being moved upward. The cassette 2-1 can be freely loaded. When a cassette photographed on another device is loaded, it can be read out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation imaging cassette and a radiation image reading apparatus used for diagnosing a disease.

[0002]

Radiation images represented by X-ray images are widely used for diagnosing diseases and the like. As means for obtaining an X-ray image, X-rays that have passed through the subject are irradiated onto the phosphor layer (fluorescent screen) to generate visible light, and the film using silver salt is irradiated with this visible light. A so-called radiograph obtained by developing this film has been conventionally used.

In recent years, X-ray CT (Computer Tom)
A method of displaying digital image information on a CRT and storing the digital image information in a magnetic recording medium or the like is widely used, as in the case of a digital camera, MRI, MRI, X-ray II camera and the like. In the field of so-called radiography using the conventional silver salt film as described above, a system capable of digitizing image information and displaying on a CRT has been devised. Further, in the field of radiography, there is a system that uses a stimulable phosphor as one of the systems that replaces the system that uses a silver salt film. Regarding such a system, as a basic system, US Pat. No. 3,859,527.

The system will be described in detail below. The phosphor used in this system is a so-called accumulative phosphor that accumulates energy in the phosphor crystal when it receives the energy of radiation such as X-rays. The stored energy is relatively stable, and the energy is retained for a while or for a long time. When the phosphor in this state is irradiated with the first light that acts as the excitation light, the stimulated emission light having the intensity corresponding to the stored energy is emitted as the second light. As the first light, not only visible light but light having a wide wavelength range from infrared to ultraviolet is used. However, the first light varies depending on the phosphor material used, and the second light also varies from infrared rays to ultraviolet rays and varies depending on the phosphor material used.

Utilizing the characteristics of the stimulable phosphor, radiation that has passed through an object such as a human body is applied to the stimulable phosphor to store and record its energy, and by reading it, a radiation image of the human body or the like is read. A radiation imaging system for obtaining information has been put into practical use. Specifically, a stimulable phosphor layer or sheet having a stimulable phosphor on which radiation information of a subject is stored and recorded is scanned with excitation light such as laser light to generate stimulated emission light, and the stimulated emission light is generated. The emitted light is collected and received, and converted into an electric signal by a photoelectric converter, whereby an electric signal proportional to the intensity of the accumulated radiation is obtained. Thereafter, this electric signal is subjected to image processing and printed on a silver salt film, or displayed on a CRT to obtain a visualized radiation image. The stimulable phosphor layer is generally a substrate layer that secures the necessary mechanical strength, a stimulable phosphor layer that stores the energy of radiation, and a protective layer that protects the stimulable phosphor layer from damage and the like. Composed of and.

The stimulable phosphor layer has its image information erased when irradiated with strong light, so that the stimulable phosphor layer can be repeatedly used for radiography. Figure 1
FIG. 1 is a schematic diagram of a conventional radiographic image reading device. A gas laser, a semiconductor laser, or the like is used as the excitation light source 3_4, and the laser beam as the excitation light is f by the scanning system of the galvanometer 3_5 (or a polygon mirror or the like).
The storage phosphor plate 3_1 having the storage phosphor layer (not shown) formed thereon is scanned in the main scanning direction through the θ lens 3_6. During this scanning, the stimulable phosphor plate 3_1 is moved in the direction orthogonal to the main scanning direction by the precision fine movement table 3_7, and the laser beam causes the stimulable phosphor plate 3_1 to move.
The entire surface of _1 will be scanned. The stimulated emission light generated by the scanning of the laser beam is condensed by the light guide path 3_8 in which a large number of optical fibers are bundled and guided to the photomultiplier 3_9. This light guide 3_8
Between the photomultiplier 3_9 and the photomultiplier 3_9, a filter (not shown) that transmits only the light having the wavelength of the stimulated emission light is arranged, and thus the stimulated emission light is guided to the photomultiplier 3_9. At this time, the light of the excitation light laser cannot pass through the filter, and the photomultiplier 3
You cannot lead to _9. The stimulated emission light selectively extracted by this filter is the photomultiplier 3_9.
Is converted into an electric signal by this, and the converted electric signal is amplified by the first stage amplifier 3_10 to a signal level optimum for A / D conversion. This amplified electric signal is converted into a digital signal by the A / D converter 3_11,
The electric signal converted into a digital signal is stored in the image memory 3_12 as an image signal, and then the image signal is converted into a display luminance signal, and the display luminance signal is converted into a CRT.
It is displayed on a film (not shown) or is output as a hard copy on a film (not shown). Since this radiation image reading device only reads the image information of the stimulable phosphor layer 3_1, such a reading device is called an "offline read-only device".

When radiography is performed by the conventional system as described above, the stimulable phosphor plate 3_1 used for the radiography is performed while being housed in the radiography cassette (see FIG. 12). There are many. This radiographic cassette is intended to prevent physical damage to the stimulable phosphor during transportation or during imaging, and to prevent the signal from disappearing due to the light hitting the stimulable phosphor after imaging. .

FIG. 12 is a perspective view showing an example of a conventional radiographic cassette. In the radiation imaging cassette 2_1 shown in FIG. 12, the stimulable phosphor plate 3_1 is housed therein, and the radiation imaging is performed in the housed state. When the stimulable phosphor plate 3_1 is irradiated with light, the image information stored and stored in the stored stimulable phosphor plate 3_1 is erased. Therefore, the radiation imaging cassette 2_1 has a high radiation transmittance, In addition, a box-shaped member made of an aluminum plate, which is a material that does not transmit light, or a carbon plate obtained by resin-molding carbon fiber is used.

The radiation emitted from the radiation source during radiography reaches the stimulable phosphor plate 3_1 through the subject such as a human body and the radiography cassette 2_1, whereby the image information of the subject is accumulated. Fluorescent phosphor plate 3_1
It is stored and recorded in. Then the radiography cassette 2
The stimulable phosphor plate 3_1 stored in _1 is manually or automatically taken out of the radiographic cassette 2_1 and read by the offline read-only device shown in FIG.

In addition to the offline read-only device shown in FIG. 11, a so-called built-in type radiation image reading device has been put into practical use. 1 for this type of reader
A radiography (exposure) unit that radiates radiation to the built-in stimulable phosphor plate 3_1 to store and record image information, and reads the image information. A reading unit and an erasing unit that erases remaining image information are provided. The stimulable phosphor plate 3_1 built in this reader is a radiographic (exposure) unit →
The reading unit and the erasing unit are circulated in this order, whereby a series of photographing and reading are performed without carrying the built-in storage phosphor plate 3_1 outside the built-in reading device.

[0011]

In the off-line read-only device shown in FIG. 11, when loading and unloading the stimulable phosphor plate 3_1, a hand or a part of the loading / unloading automatic device contacts the stimulable phosphor plate 3_1. In that case, the stimulable phosphor plate 3_1 is physically damaged and the image information thereof is damaged, and the stimulable phosphor plate 3_1 is also damaged.
There is a problem in that dust, fingerprints, etc. adhere to the surface and its optical performance deteriorates.

Further, the built-in type reading device is
The stimulable phosphor plate 3_1 contained in the apparatus can be imaged and read only, and the stimulable phosphor plate 3_1 housed inside the radiographic cassette 2_1 shown in FIG. 12 is of a built-in type. Not compatible with readers. For this reason, even if you have a built-in type reader, if you need to shoot at a location away from the installation location of the built-in type reader, or if you use the built-in type reader When it is necessary to take an image of a body position or a part that cannot be performed, an image is taken on the stimulable phosphor plate housed in it using a radiographic cassette,
When reading the image information of the stimulable phosphor plate 3_1 stored inside the radiation imaging cassette, the built-in type reading device having a reading function is not useful, and the offline reading only device shown in FIG. 11 is used. It is necessary to use them, and it is difficult to arrange both readers in terms of price and space.

In view of the above circumstances, the present invention prevents the image information stored and recorded in the stimulable phosphor layer from being impaired and prevents the deterioration of the optical performance thereof, and a radiographic cassette. It is an object of the present invention to provide a radiographic image reading apparatus suitable for both imaging using the apparatus and imaging away from the apparatus.

[0014]

A radiographic cassette according to the present invention for achieving the above object has a lid that can be opened and closed and has a stimulable phosphor layer that is fixed inside and extends along the lid. It is characterized by that. Here, it is preferable that the lid slides along the stimulable phosphor layer to open and close.

Further, the substrate layer fixed inside, the stimulable phosphor layer formed on the surface of the substrate layer, and the stimulable phosphor layer sandwiched between the substrate layer and the storage layer. It is a preferable configuration to have a protective layer for protecting the fluorescent layer. Further, the stimulable phosphor layer is formed on the inner wall surface of the radiographic cassette, and the stimulable phosphor layer thus formed is sandwiched between the inner wall surface of the radiographic cassette and the storability. It may be configured to have a protective layer that protects the phosphor layer.

It is also preferable that the stimulable phosphor layer is fixed to the radiation imaging cassette with a light reflection layer interposed therebetween. Also, the lid includes a radiation shielding material,
Alternatively, it is also preferable that the protective layer contains a radiation shielding material. In addition, the radiation image reading apparatus of the present invention for achieving the above object is equipped with a lid that can be opened and closed, and can be loaded with a radiation imaging cassette that has a stimulable phosphor layer that is fixed inside and spreads along the lid. And a photographing unit for accumulating and recording a radiation image on the stimulable phosphor layer in the loaded radiographic cassette, and the stimulable phosphor layer in the radiographic cassette two-dimensionally by excitation light. And a reading unit for scanning and receiving stimulated emission light generated from the stimulable phosphor layer.

[0017]

Since the radiographic cassette of the present invention has the stimulable phosphor layer fixed inside the cassette, the stimulable phosphor layer is not loaded from the radiographic cassette. Physical damage to the stimulable phosphor layer is prevented. Further, since this radiographic cassette is provided with a lid that can be opened and closed, the image information stored and recorded in the stimulable phosphor layer can be read by opening the lid.

Further, if the lid is configured to slide along the stimulable phosphor layer to open and close, the lid can be opened and closed even in a narrow space. Further, when the substrate layer is fixed inside the radiation imaging cassette and the stimulable phosphor layer is formed on the surface of the substrate layer, the strength of the stimulable phosphor layer is secured. Further, when a protective layer for protecting the stimulable phosphor layer is formed on the surface of the stimulable phosphor layer, damage to the stimulable phosphor layer is further prevented.

When the stimulable phosphor layer is formed on the inner wall surface of the radiographic cassette, the radiographic cassette ensures the strength of the stimulable phosphor layer.
The substrate layer can be omitted. When the stimulable phosphor layer has a configuration in which it is fixed to the radiation imaging cassette with a light reflection layer interposed therebetween, the light reflection layer reflects the light of stimulated emission light well, and Effective reading becomes possible.

Further, when the lid or the protective layer contains a radiation shielding material, a virtual image due to radiation is prevented from being generated in the stimulable phosphor layer. Further, in the radiation image reading apparatus of the present invention, the radiation imaging cassette is loaded in a freely attachable manner, and further, since the radiation imaging cassette is also provided, the radiation imaging cassette is loaded in the apparatus first. After that, the apparatus can be used for image taking and reading, or the apparatus can be taken away from the apparatus and then the radiographic cassette on which the image is taken can be loaded for reading.

[0021]

EXAMPLES Examples of the present invention will be described below.
The same elements as those in the configuration of the above-mentioned conventional technique (see FIGS. 11 and 12) are denoted by the same reference numerals, and the duplicate description will be omitted. 1 (a) is a perspective view showing an example of the radiographic cassette of the present invention, and FIG. 1 (b) is shown in FIG.
It is an AA sectional view of (a).

The radiation imaging cassette 2_1 has a stimulable phosphor plate 3_1 fixed inside. Further, the radiation imaging cassette 2_1 is provided with a cassette lid 2_2 that can be opened and closed in the left and right directions in FIG. This cassette lid 2_2 is a cassette for radiography 2
It is held in guide grooves (not shown) provided on both inner side surfaces facing each other and slides along the stimulable phosphor plate 3_1. Further, a rubber packing or the like for shielding light is attached to the guide groove, so that the radiation imaging cassette 2_1 becomes a dark box when the cassette lid 2_2 is closed. In addition, the radiation is irradiated from the lower side to the upper side in FIG. 1B toward the radiation imaging cassette 2_1, and the radiation that has passed through the radiation imaging cassette 2_1 is applied to the stimulable phosphor plate 3_1. The image information accumulated and recorded on the stimulable phosphor plate 3_1 is read from above in FIG. 1B with the cassette lid 2_2 opened.

FIG. 2 is a sectional view showing an example of the radiographic cassette, and FIG. 2 (a) is a sectional view of the whole,
(B) is an enlarged partial cross-sectional view. 3 and 4 are partial cross-sectional views showing modifications of the example shown in FIG. Inside the radiation imaging cassette 2_1, a stimulable phosphor layer 4_4 is fixed to the bottom surface facing the cassette lid 2_2 with an adhesive such as an epoxy resin, and a protective layer 4 is provided thereon.
_3 is stacked.

Further, the radiographic cassette 2 shown in FIG.
_1 is a light reflection layer 4_5 → a stimulable phosphor layer 4_4 → a protective layer 4 on the bottom surface thereof from the bottom to the top in FIG.
_3 is laminated in this order. Here, the light reflection layer 4
_5 is a metal plate having a mirror surface, or a glass or other surface on which a reflective material is vapor-deposited, and is for efficiently reflecting the excitation light and the stimulated emission light.

Further, the radiographic cassette 2_1 shown in FIG. 4 is formed by stacking a stimulable phosphor layer 4_4 and a protective layer 4_3 on the bottom surface thereof in this order. A lead plate 4_6 is adhesively fixed to the inner surface of the cassette lid 2_2.
This is because the radiation that has passed through the bottom surface and the stimulable phosphor layer 4_4 may cause so-called backscattering, which may form a virtual image on the stimulable phosphor layer 4_4, which is provided to prevent this backscattering. It has been done. As the lead plate 4_6, a lead plate having a large radiation absorption rate, for example, a thickness of 0.1 mm to 3 mm, or a powder of a material having a large radiation absorption rate such as lead powder, lead oxide powder, or tungsten powder is used as a resin. What is hardened by and is molded into a sheet is used.

FIG. 5 is a sectional view showing another example of the radiographic cassette shown in FIG. 1. FIG. 5 (a) is an overall sectional view and FIG. 5 (b) is an enlarged partial view. FIG.
6 and 7 are partial cross-sectional views showing modified examples of the example shown in FIG. Radiographic cassette 2_1 shown in FIG.
Is laminated on the bottom surface in the order of the substrate layer 4_7 → the storage phosphor layer 4_4 → the protective layer 4_3 from the bottom to the top in FIG.

Further, the radiographic cassette 2 shown in FIG.
_1 is a light reflection layer 4_5 → a substrate layer 4_7 → a stimulable phosphor layer 4_4 on the bottom surface thereof from below to above in FIG.
→ The protective layer 4_3 is laminated in this order. These substrate layer 4_7, stimulable phosphor layer 4_4 and protective layer 4_3 are
The substrate layers 4_7 are fixed to each other and to the bottom surface of the radiographic cassette 2_1. The fixation to the radiation imaging cassette 2_1 may be performed by an adhesive or the like, or may be mechanically fixed by a screw or the like.

Further, the radiographic cassette 2_ shown in FIG.
Similar to the example of FIG. 5, 1 includes a substrate layer 4_7, a stimulable phosphor layer 4_4 and a protective layer 4_3, and further, a lead plate 4_6 is adhesively fixed to the inner surface of the cassette lid 2_2. In the above embodiment, the light reflection layer 4_5 and the lead plate 4_6 are used.
Although the description above is provided separately, it goes without saying that both may be provided. In addition, the lead plate 4_6
The cassette lid 2_2 is provided to prevent the generation of a virtual image due to backscattering, but as another method for preventing backscattering, so-called lead glass containing a large amount of lead in the protective layer 4_3 may be used. . In this case, this protective layer 4_3
Will have both the role of protecting the stimulable phosphor layer 4_4 and the role of radiation shielding.

FIG. 8 (a) is a perspective view showing still another example of the radiographic cassette of the present invention, and FIG. 8 (b) is shown in FIG.
It is a BB sectional view of (a). The radiation imaging cassette 2_1 has a structure in which one side of the cassette lid 2_2 of the radiation imaging cassette 2_1 is rotatably attached by a hinge (not shown). The radiation imaging cassette 2_1 of the present invention may be configured to include a lid that opens and closes in this manner.

FIG. 9 is an external view showing an example of the radiation image reading apparatus of the present invention. This radiation image reading device 6_1
9A, a radiation irradiation surface 6_2 on which radiation is emitted and a cassette loading port 6 into which the radiation imaging cassette 2_1 is loaded inside the reading device 6_1.
_3 is provided. FIG. 9B shows a radiation imaging cassette 2_1 in addition to the radiation image reading apparatus shown in FIG.
It is a figure showing the state where is loaded.

The radiation imaging cassette 2_1 is loaded from the cassette loading port 6_3 so that the cassette lid 2_3 is directed toward the excitation light main scanning unit 7_4 (see FIG. 10) inside the reading device 6_1. FIG. 9C is a diagram showing a state in which the cassette lid of the radiation imaging cassette loaded in the radiation image reading device is taken out.

When the radiation imaging cassette 2_1 is loaded in the radiation image reading device 6_1, the cassette lid 2_2 is pulled out of the reading device 6_1. In this state, the radiation image reading device 6_1 carries out imaging on the radiation imaging cassette 2_1 and reading of the image information thereof. The cassette lid 2_2 may be opened and closed manually. A rubber roller or the like may be provided inside the reading device 6_1, and the cassette lid 2_2 may be opened or closed by the rubber roller or the like.
You may open and close automatically. In addition, the cassette lid 2_2
The withdrawal may be performed immediately after reading after photographing using this apparatus.

FIG. 10A is a sectional view taken along line CC of FIG. 9C. The radiation irradiation surface 6_2 includes a carbon plate 7_1 having a high radiation transmittance, a scattered radiation removing grid 7_2, and a phototimer sensor unit 7_3. A radiographic cassette 2_1 is mounted on the right side in FIG. 6 of the phototimer sensor section 7_3. Further, the excitation light main scanning unit 7_4 that moves up and down is screwed and held by the vertically extending screw rod 7_8. The excitation light main scanning unit 7_4 includes a light source that emits excitation light such as a laser shown by an arrow, an optical deflector such as a polygon mirror, and a lens system such as an fθ lens (none of which is shown).
The excitation light main scanning unit 7_4 is used for the radiographic cassette 2
The uniform excitation light is main-scanned on the storage phosphor layer 4-4 of _1. Further, the excitation light main scanning unit 7_4 is connected with a light collecting / light guiding path 7_5 for collecting the stimulated emission light generated from the stimulable phosphor layer 4_4 by the excitation light.
A photomultiplier tube 7_6 for amplifying the stimulated emission light is connected to the light guide path 7_5. Further, the excitation light main scanning unit 7
An eraser 7_7, which is a combination of a halogen lamp and a reflection mirror, for erasing image information remaining in the stimulable phosphor layer 4_4, is connected to _4.

The excitation light main scanning section 7_4 moves from the state shown in FIG. 10A to the lower side of the radiation imaging cassette 2_1 after the radiation imaging cassette 2_1 is irradiated with radiation and the radiation imaging is completed. The image information stored and recorded in 2_1 is read. FIG. 10B is a diagram showing a state in which the excitation light main scanning unit has finished reading the image information accumulated in the radiation imaging cassette.

When the reading operation is completed, the excitation light main scanning section 7_4 turns on the lamp of the erasing device 7_7 and moves upward in FIG.
The image information remaining in _1 is erased, and the excitation light main scanning unit 7_
4 returns to the position of FIG. Here, in the above-described embodiment, the case where the radiation irradiation surface 6_2 is applied to the three-dimensional type device on the side surface of the reading device is shown, but a so-called recumbent reading device having the radiation irradiation surface 6_2 on the upper surface or Of course, the same can be applied to devices having other shapes.

[0036]

As described above, since the radiographic cassette of the present invention has the stimulable phosphor layer fixed inside the cassette, the stimulable phosphor layer can be removed from the radiographic cassette. Not loaded, this prevents physical damage to the stimulable phosphor layer and degradation of its optical performance.

Further, since the radiation image reading apparatus of the present invention is loaded with the above-described radiation imaging cassette of the present invention in a freely loadable manner, this reading apparatus is a radiation imaging apparatus that takes an image by using another imaging apparatus. It can also be read by loading a cassette for use.

[Brief description of drawings]

FIG. 1 is a perspective view (a) showing an example of a radiographic cassette of the present invention, and a sectional view (b) taken along the line AA of (a).

FIG. 2 is a cross-sectional view showing an example of a radiographic cassette.

FIG. 3 is a partial cross-sectional view showing a modified example of the example shown in FIG.

FIG. 4 is a partial cross-sectional view showing a modified example of the example shown in FIG.

FIG. 5 is a cross-sectional view showing another example of the radiographic cassette, which is a whole cross-sectional view (a) and a partially enlarged view (b) shown in an enlarged manner.

FIG. 6 is a partial cross-sectional view showing a modified example of the example shown in FIG.

FIG. 7 is a partial cross-sectional view showing a modified example of the example shown in FIG.

FIG. 8 is a perspective view (a) showing a further different example of the radiographic cassette of the present invention, and a BB cross-sectional view (b) of (a).

FIG. 9 is an external view showing an example of a radiation image reading apparatus of the present invention.

10 is a cross-sectional view taken along the line CC of FIG. 9 (c).

FIG. 11 is a schematic view of a conventional radiographic image reading device.

FIG. 12 is a perspective view showing an example of a conventional radiographic cassette.

[Explanation of symbols]

 2_1 Radiographic cassette 2_2 Cassette lid 3_1 Storage phosphor plate 4_3 Protective layer 4_4 Storage phosphor layer 4_5 Light reflection layer 4_6 Lead plate 6_1 Radiation image reader 6_2 Radiation irradiation surface 6_3 Cassette loading port

Claims (8)

[Claims] 1. A radiographic cassette comprising a lid that can be opened and closed, and a stimulable phosphor layer that is fixed inside and extends along the lid. 2. The cassette for radiography according to claim 1, wherein the lid is opened and closed by sliding along the stimulable phosphor layer. 3. A substrate layer fixed inside, the stimulable phosphor layer formed on the surface of the substrate layer, and the stimulable phosphor layer sandwiched between the substrate layer and the storage layer. The cassette for radiography according to claim 1, further comprising a protective layer that protects the luminescent phosphor layer. 4. The stimulable phosphor layer is formed on the inner wall surface of the radiation imaging cassette, and the formed stimulable phosphor layer is sandwiched between the inner wall surface of the radiation imaging cassette. The cassette for radiography according to claim 1, further comprising a protective layer for protecting the stimulable phosphor layer. 5. The radiographic cassette according to claim 1, wherein the stimulable phosphor layer is fixed to the radiographic cassette with a light reflection layer interposed therebetween. 6. The radiographic cassette according to claim 1, wherein the lid includes a radiation shielding material. 7. The cassette for radiography according to claim 3, wherein the protective layer contains a radiation shielding material. 8. A radiographic cassette having an openable / closable lid and having a stimulable phosphor layer fixed inside and extending along the lid is removably loaded in the loaded radiographic cassette. An imaging unit that stores and records a radiation image on the stimulable phosphor layer, and the stimulable phosphor layer in the radiation imaging cassette is two-dimensionally scanned with excitation light to generate from the stimulable phosphor layer. A radiation image reading apparatus comprising: a reading unit that receives stimulated emission light.