JP3015147B2 - X-ray equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing X-ray photography, and more particularly to an X-ray photography apparatus for performing photography in a state in which a film and an intensifying screen are brought into close contact with each other by reducing the space containing the film.

[0002]

2. Description of the Related Art FIG. 11 is a diagram showing an outline of an X-ray imaging system for X-ray imaging of a chest of a subject.
Is an X-ray source having an X-ray tube, 102 is a subject, 103 is an X-ray imaging apparatus, and 104 is a mount supporting the X-ray imaging apparatus. FIG. 12 shows the X-ray imaging apparatus 103 in FIG.
105 is a supply magazine for storing unphotographed X-ray film, and 106 is a receive magazine for storing filmed film. Reference numeral 107 denotes a chest pad on which the subject adheres to the chest, and a photographic stage for setting a photographic film is provided inside the chest pad. , An X-ray image of the chest of the subject is printed on the film.

FIG. 13 shows an example of the internal structure of a conventional X-ray imaging apparatus. In the state shown in FIG. 13, the film has already been conveyed to the photographing stage, and the close contact between the film and the intensifying screen has been completed. An imaging stage of a conventional X-ray imaging apparatus generally has a configuration as shown in the figure. 25 from the X-ray source side
Numeral 19 denotes a chest pad for bringing the subject into close contact with the chest, and numeral 19 denotes a grid which is a scattered ray removing member for removing scattered rays generated from the subject when X-rays pass through the subject and degrading image quality. 1
Reference numeral 4 denotes a phototimer which is a detector for detecting the intensity of the X-ray transmitted through the subject, and controls the film exposure based on the output of the phototimer so as to make the film exposure proper. The phototimer 14 has a configuration which will be described later, and has a surface having almost the same X-ray transmittance as that of the film surface, which is substantially uniform. 9
Is a front intensifying screen, 10 is a rear intensifying screen, and each intensifying screen is X
It has an action of generating visible light in response to rays, and an X-ray film F is sandwiched between the two. The front intensifying screen 9 is attached to the front support member 17, and the rear intensifying screen 10 is attached to the rear support member 11. Reference numeral 15 denotes a lead plate disposed between the rear intensifying screen 10 and the rear supporting member 11, which shields the back scattered radiation generated through the rear intensifying screen 10 and hitting the rear member. Has the effect of eliminating adverse effects on the film. Reference numeral 3 denotes a supply magazine for stacking and storing unused films. Reference numeral 4 denotes a receive magazine for storing photographed films. A single film F taken out of the supply magazine 3 by a separation mechanism (not shown) is conveyed to a photographing stage by conveying means such as a pair of rollers 5, 6 and a guide plate 16. When the film F is conveyed to the photographing stage, the rear support member 11 and the rear intensifying screen 10 are at positions shown by two-dot chain lines in the figure. In this state, after the film F is fed between the front intensifying screen 9 and the rear intensifying screen 10, the rear supporting member 11 to which the rear intensifying screen 10 is attached is moved in the direction of arrow A to support the rear. The member 11 is pressed against the front support member 17 so that the front intensifying screen 9 and the rear intensifying screen 10 sandwich the film F therebetween. The rear support member 11 is connected to the front support member 1.
7 with a strong mechanical force to make the film and the intensifying screen adhere to each other.
1 is required to have high rigidity, and a member having a thickness of, for example, 2.5 mm is used. In this way, X-ray photography is performed on the photography stage with the film and the intensifying screen in close contact with each other.

[0004]

In order to obtain a high-quality X-ray photograph, it is important to minimize the distance between the subject and the film to reduce the geometric blur.
Further, at the same time as minimizing the scattered radiation generated from the members existing between the subject and the film, the members existing between the subject and the film are also minimized in order to minimize the radiation exposure to the subject. It is desirable to remove as much as possible. However, in the configuration of the conventional X-ray imaging apparatus exemplified above, there is a chest pad between the subject and the film, a grid, a photo timer, a thick front support member, and the like. Increases the geometric blur. Further, although a high-rigidity thick material is used for the front-side support member, scattered radiation is generated from this material, and furthermore, X-rays are greatly attenuated, which is a factor of deteriorating the image quality of the film.

There is also a problem caused by the phototimer being arranged between the subject and the film. FIG. 14 is a diagram for explaining a typical configuration of a photo timer.
31 is a phosphor layer, 32 is a mask, 33 is an acrylic plate, 3
4 is a photomultiplier for detecting light, 35 is a lighting field with a mask 32 cut out, and 36 is a photomultiplier 34
Is the output line connected to. X-rays applied to the phosphor layer 31 generate fluorescent light. Among them, the light that has passed through the lighting field 35 of the mask 32 is guided to a photomultiplier 34 to be photoelectrically converted and detected.

Here, in order to prevent the shadow of the lighting field 35 from being reflected on the film, the phosphor layer must be uniformly applied to the entire surface except for the lighting field to uniformly attenuate the X-rays. The acrylic plate 33 as a light guide also needs to be uniform and at least the same size as the film. Therefore, it is difficult to reduce the size of the phototimer, and there is no design freedom, which hinders cost reduction.

Further, the generated fluorescence is very small. To increase the detection sensitivity of the phototimer, a method of increasing the thickness of the phosphor layer 31 or increasing the detection sensitivity of the photomultiplier can be considered. However, since the phototimer is placed in front of the film, the phosphor layer 31 that attenuates the amount of X-rays reaching the film cannot be made too thick. Also, if the detection sensitivity of the photomultiplier is increased, the detection S / N ratio will be deteriorated. Further, there is a problem in that scattered X-rays are generated from the phototimer itself, thereby deteriorating the image quality of the film.

These problems are caused by the phototimer being located in front of the film. However, conventionally, the supporting member is thick, and scattered rays are generated and X-ray absorption is large. It was difficult to locate the phototimer in the area.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide an X-ray imaging apparatus capable of obtaining a high-quality X-ray image with low exposure.

[0010]

According to one embodiment of the present invention, an intensifying screen is attached to at least one of a pair of support members, and a film is provided between the support members. An X-ray imaging apparatus for performing X-ray photography in a state where the space between the support members is sealed and the inside of the sealed space is decompressed and the intensifying screen and the film are brought into close contact with each other. Alternatively, the front support member is made of an X-ray low-absorbing substance, and a grid is detachably mounted on the X-ray generation side of the front support member. In another embodiment of the X-ray imaging apparatus according to the present invention, an X-ray detecting means for controlling an exposure amount of the film is further arranged behind the fed film in the above-described configuration. Alternatively, an intensifying screen is attached to at least one of the pair of supporting members, a film is fed between the supporting members, the space between the supporting members is sealed, and the inside of the sealed space is decompressed to reduce the intensifying screen and the film. An X-ray imaging apparatus for performing X-ray imaging in a state in which the X-rays are in close contact with each other, wherein the front support member is made of an X-ray low-absorbing substance, and a grid is arranged on the X-ray generation side of the front support member. With a breastplate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the X-ray imaging apparatus according to the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an internal configuration of an X-ray imaging apparatus for the chest or abdomen of a subject, and shows a state when a film is fed to an imaging stage. 2 and 3 are partial perspective views of members near the photographing stage.

In FIG. 1, the inside of an X-ray imaging apparatus is a housing 1.
And the plate-shaped front support member 2 keeps light tight.
In the present embodiment, in order to obtain a clear image by making the distance between the subject and the film as close as possible, the front support member 2 is provided with scattered radiation having an action of removing scattered radiation generated from the subject. A grid is used in this embodiment. Further, the front support member 2 also functions as a breastplate. This configuration contributes to improving the image quality and reducing the thickness of the device. The unphotographed film is stored in the supply magazine 3 and the photographed film is stored in the receive magazine 4. Roller pairs 5, 6, 7 and a guide plate 1 are used as transport means for loading and unloading the film to and from the photographing stage.
6 are provided. As shown in FIG. 2, a packing 8 and a front intensifying screen 9 having both airtightness and flexibility are attached to the front support member 2 by a method such as bonding. FIG.
As shown in the perspective view of FIG. 1, the rear intensifying screen 10 is attached to a flexible plate-like rear support member 11, and the rear support member 11 is attached to a frame 12. The intensifying screen does not necessarily need to be provided on both the front side and the rear side. If at least one of them is provided, an image can be obtained on a film. It is desirable that the rear support member 11 be thin and have a uniform structure with little X-ray absorption (for example, chloroprene rubber having a thickness of 0.3 mm). A photo timer 14 as X-ray detecting means is installed inside the frame of the frame 12 by the mounting plate 13, but the shape and arrangement of the photo timer 14 are not limited to those shown in FIG. Further, a lead plate 15 serving as a backscattered light shielding member is disposed behind the photo timer 14.
5 allows the X-rays transmitted through the phototimer 14 to block backscattered rays generated when the X-rays strike a rear member. The lead plate 15 has a size that covers the entire surface of the film. As described above, one of the features of the present embodiment is that the phototimer 14 is disposed behind the film held on the photographing stage. This is because the grid, the front support member, and the breastplate are made into one member, and Such an arrangement became possible because the scattered X-ray and X-ray absorption were reduced by making the side support member thin. By arranging the phototimer 14 behind the film, various problems caused by arranging the phototimer in front of the photographing stage as described in the prior art can be solved at once. X that reaches the film
Since the X-ray attenuation of the X-ray is small, the X-ray irradiation dose can be reduced, and there is also a great merit that the exposure dose of the subject is small.

Further, since the phototimer 14, which is an X-ray detector, is placed behind the film, the degree of freedom in the shape and arrangement of the phototimer is greatly increased. FIG. 5 is a diagram showing an example. Reference numeral 31 denotes a phosphor layer having the same shape as that of the lighting field shown in the conventional example of FIG. 14, 33 denotes an acrylic plate, and 34 denotes a photomultiplier. These members constitute the phototimer 14. Unlike the conventional case, the size over the entire surface of the film is not required, so that downsizing can be achieved and a mask is not required. Further, since the phosphor layer is placed behind the film, the thickness of the phosphor layer can be increased, and there is no problem that shadows are reflected. Therefore, there is an advantage that it is not necessary to apply unnecessary phosphor.

Next, the operation of the above configuration will be described.
In FIG. 1, one film F is selected from a number of sheets stacked and stored in the supply magazine 3 by a take-out mechanism (not shown).
Is taken out, and the taken out film F is a pair of rollers 5,
6 is fed to the front surface of the rear intensifying screen 10 from above by the drive of the drive 6. The fed film F is held at a specified position by a holding mechanism (not shown) so as not to shift downward. This is because the holding and photographing is performed in a state where the film is set up in the vertical direction, so that the film is provided to prevent the film from being shifted downward by gravity when the film is taken in and out of the stage. As a specific example of the holding mechanism, a method of holding by suction as described in Japanese Patent Application No. 3-3254 is suitable.
When the frame body 12 is rotated in the direction of arrow B in FIG. 1 in this state, the rear support member 11 comes into close contact with the packing 8 as shown in FIG. 4, and the front support member 2, the packing 8, and the rear support member 11
The space surrounded by is enclosed to form a closed space containing the film F. When the pressure in the closed space is reduced by a pressure reducing means (not shown) having a suction pump or the like, the flexible rear support member 11 is bent by the atmospheric pressure, and the front support member 2 is bent.
, The front intensifying screen 9, the film F, and the rear intensifying screen 10 are held in close contact with each other. This is a so-called vacuum contact method. At this time, the front support member 2 is also pressed in the direction of the rear support member 11 by the same atmospheric pressure, so that the two are pressed by the same force to maintain a balanced state, and the front support member 2, ie, the grid is deformed. There will be no excessive force. By adopting the vacuum contact method in this manner, it is possible to form a relatively low-strength grid without using a highly rigid member for the front support member 2 as in the related art.

X-ray photography is performed in this state. The X-rays emitted from the X-ray source to the subject are selectively absorbed and transmitted by tissues of various parts in the body of the subject, and are incident on the surface of the front support member 2 having a scattered radiation removing action. When the subject is exposed to X-rays, scattered X-rays that degrade the image quality are generated. These scattered rays are selectively absorbed by the scattered ray removing action of the front support member 2. Therefore, so-called primary X-rays, which are effective for forming an X-ray image, selectively reach the intensifying screens 9 and 10 on the film. Is emitted to form a chest X-ray image of the subject on the film.
At this time, some X-rays pass through the rear intensifying screen 10 and the rear support member 11 and reach the photo timer 14. When the appropriate exposure amount is reached based on the output of the photo timer 14, the control is performed so as to cut off the generation of X-rays, and the X-ray imaging is completed. The film that has been photographed is transported by a pair of rollers 6 and a guide plate 1.
6. It is fed into the receive magazine 4 by the roller pair 7.

The X-rays that have reached the phototimer 14 generate scattered radiation from the phototimer 14 itself. Most of the scattered radiation is a component in the traveling direction of the X-rays, and there is only a small amount of backscattered radiation traveling in the opposite direction. It is. For this reason, the degree of image quality degradation due to scattered radiation generated from the phototimer 14 itself is extremely small as compared with the conventional case where the phototimer 14 is disposed between the subject and the film F. Further, although a little, the X-rays penetrate further rearward and strike back members, generating backscattered rays. However, these scattered rays are shielded by the lead plate 15 and do not affect the image quality.

FIG. 6 is a diagram for explaining the exposure amount control based on the output of the photo timer 14. During irradiation of the subject 102 with X-rays from the X-ray source 101, the X-ray imaging apparatus 1
The X-ray intensity is detected by a photo timer 14 in 03 and photoelectrically converted. The output is integrated by an integrator 40 having a capacitor. The accumulated charge integrated by the integrator 40 represents the exposure amount of the film. The comparator 41 compares a reference value indicating an appropriate exposure amount preset by the film density setting means 42 with an integral value of the integrator 40. Then, when the integrated value reaches the reference value, the X-ray light voltage generating means 43 is controlled to stop the X-ray irradiation from the X-ray source 101, and the imaging ends.

In the configuration of the above embodiment, the photo timer 1
4 is mounted inside the frame 12 so that the phototimer moves with the rotation of the frame. As a modification, when the phototimer 14 is rotated behind the frame 12 as shown in FIG. Alternatively, a configuration may be adopted in which the frame 12 is fixed at a position where the rotation of the frame 12 is not hindered, and the back scattered radiation shielding member 15 is further disposed behind the frame 12.

According to the above embodiment, the distance between the subject and the film is reduced by reducing the number of members existing between the subject and the film, and a good image with a small geometric blur can be obtained. At the same time, the influence of scattered radiation generated from the member between the subject and the film can be minimized, and further, the X-ray absorption by the member between the subject and the film can be minimized. Therefore, an X-ray imaging apparatus with high image quality and low exposure can be provided.

By arranging an X-ray detecting means such as a photo timer behind the photographing stage, a high quality image can be obtained because there is no shadow of the photo timer on the film and no influence of scattered radiation from the photo timer as in the conventional case. As well as
The degree of freedom in the shape and arrangement of the X-ray detection means is increased, and various types of X-ray detection means can be used.

Another Embodiment FIG. 8 is a block diagram of another embodiment of the present invention. In the drawing, the same reference numerals as those in the previous embodiment denote the same or equivalent members. The grid 19 is fixed to the housing 1 and also functions as a breastplate. Reference numeral 17 denotes a front support member provided separately from the grid 19, to which the front intensifying screen 9 and the packing 8 are attached. The lower portion of the front support member 17 is hinged to the frame 12.
8 and can be opened and closed freely and can rotate integrally with the frame 12. Since the front support member 17 is present between the subject and the film, a material having a small thickness and low X-ray absorption is preferable, and an example thereof is carbon fiber. In the present invention, since the photographing stage is hermetically sealed and depressurized by the so-called vacuum contact method to adhere the film and the intensifying screen, the strength of the front support member 17 is the conventional type in which the rear support member is mechanically pressed against the front support member. X is made of thinner carbon fiber than before.
It consisted of a line low absorption member. The thickness of the carbon fiber is preferably less than 2.5 mm, more preferably less than 1.0 mm, and most preferably about 0.5 mm to 0.6 mm. Further, it is needless to say that members made of various materials can be used without being limited to carbon fibers.

A rear support member 11 such as rubber, a rear intensifying screen 10, a phototimer 14, and a lead plate 15 are attached to the frame 12 in the same manner as in FIG. The shape and the degree of freedom of arrangement of the phototimer 14 are the same as those of the previous embodiment.
In the state shown in FIG. 8, the film F is fed from the supply magazine 3 to the front surface of the rear intensifying screen 10, and the film is held at a predetermined position by a holding mechanism (not shown). Then, the space is closed by the packing 8 and the rear support member 11 to form a sealed space containing the film F. Then, pressure reduction in the closed space is started by a pressure reducing mechanism (not shown), and the close contact between the film F and the intensifying screens 9, 10 is started. Usually, several seconds to several tens of seconds are required for the decompression, but during this depressurization period, this unit is moved to a position just behind the grid 2 of the photographing stage by the hinge 18 around the support shaft by a mechanism (not shown). That is, since the shift is performed during the decompression, the throughput is improved as compared with the previous embodiment. X-ray photography is performed with the unit fixed at the shifted position, and after photography, the film returns to the state shown in FIG.

When the film is taken in and out of the photographing stage by modifying the structure of this embodiment, the stage is completely laid down to a horizontal state or a state close to it, and the film is carried into the stage in the horizontal state and sealed. Alternatively, the unit may be turned 90 degrees while the decompression is started to shift to a photographable state. By adopting such a configuration, the film is in a horizontal state when there is no close contact force by the intensifying screen at the time of loading and unloading, so that the film does not slip off due to gravity, and the film holding mechanism becomes unnecessary.

According to the present embodiment, since the distance between the subject and the film is small, the generation of scattered radiation and the attenuation of X-rays are small, a good photographed image can be obtained and the X-ray irradiation amount can be reduced. Low exposure. Further, since the pressure reduction and the transfer are performed simultaneously, the throughput is improved.

Another Embodiment Next, a further embodiment of the present invention will be described with reference to FIG. In this embodiment, grids having different focal lengths can be exchanged according to the imaged region so that a single device can be used to image different regions. For example, considering the case of imaging the chest and abdomen of the subject, since the abdomen absorbs more X-rays than the chest, in the case of chest imaging, the distance between the X-ray source and the film is set to about 180 cm, In the case of photographing, it is set to about 150 cm, and grids having different focal lengths corresponding to the respective distances are used.

In the previous embodiment shown in FIG. 1, the front support member was constituted by a grid to minimize the distance between the subject and the film, and the front intensifying screen 9 was directly attached to the grid.
In this embodiment shown in FIG. 9, the front intensifying screen 9 is attached to the front support member 17 having low X-ray absorption and light shielding properties, and the replaceable grid 19 is disposed in front of the front support member 17. The grid 2 is detachably held along the rail 18, and is fixedly held at a specified position by a stopper when the grid 2 is mounted on the apparatus. FIG. 10 shows how the grid 2 slides along the rail 18. Front support member 17
Has a light-shielding property, so that the light-shielding inside the device is maintained even when the grid is replaced.

Since the front support member 17 exists between the subject and the film, a material having a small plate thickness and a small X-ray absorption is preferable, and an example thereof is a carbon fiber. In the present invention, since the photographing stage is hermetically sealed and depressurized by the so-called vacuum contact method to adhere the film and the intensifying screen, the strength of the front support member 17 is the conventional type in which the rear support member is mechanically pressed against the front support member. X is made of thinner carbon fiber than before.
It consisted of a line low absorption member. The thickness of the carbon fiber is preferably less than 2.5 mm, more preferably less than 1.0 mm, and most preferably about 0.5 mm to 0.6 mm. Further, it is needless to say that members made of various materials can be used without being limited to carbon fibers.

According to the present embodiment, the grid can be easily exchanged according to the part to be photographed, and it is possible to cope with various kinds of photographing. In addition, since the distance between the subject and the film is small and the attenuation of scattered X-rays and X-rays is small, a good photographed image can be obtained, and the X-ray irradiation amount can be reduced to achieve low exposure. .

[0029]

According to the X-ray photographing apparatus of the present invention, a high quality photographed image can be obtained with low exposure, and the degree of freedom of the shape and arrangement of the X-ray detecting means is increased, so that various types of X-ray detection can be performed. Means can be used.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of an X-ray imaging apparatus according to an embodiment of the present invention, showing a state where a film is sent to an imaging stage.

FIG. 2 is a partial configuration diagram centering on a front support member.

FIG. 3 is a partial configuration diagram centering on a rear support member.

FIG. 4 is an internal composition of the embodiment, showing a state in which preparation for photographing is completed.

FIG. 5 is a diagram showing an example of the shape of a photo timer.

FIG. 6 is an explanatory diagram of exposure amount control.

FIG. 7 is a modified embodiment of the embodiment.

FIG. 8 is a configuration diagram of another embodiment of the present invention.

FIG. 9 is a configuration diagram of still another embodiment of the present invention.

FIG. 10 is an external view of still another embodiment of the present invention.

FIG. 11 is a schematic diagram of a chest X-ray imaging system.

FIG. 12 is an external view of an X-ray imaging apparatus.

FIG. 13 is an internal configuration diagram of a conventional X-ray imaging apparatus.

FIG. 14 is a configuration example of a conventional phototimer.

[Explanation of symbols]

 2 Front support member (grid) 3 Supply magazine 4 Receive magazine 8 Packing 9 Front intensifying screen 10 Rear intensifying screen 11 Rear support member 12 Frame 14 Phototimer 15 Lead plate 17 Front support member 19 Grid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03B 42/02-42/04 A61B 6/06

Claims (8)

(57) [Claims] 1. An intensifying screen is attached to at least one of a pair of support members, a film is fed between the support members, the space between the support members is sealed, and the inside of the closed space is decompressed to reduce the sensitization. What is claimed is: 1. An X-ray imaging apparatus for performing X-ray imaging in a state in which paper and a film are in close contact with each other, wherein the front support member is configured by a grid . 2. An intensifying screen is attached to at least one of the pair of support members, a film is fed between the support members, the space between the support members is sealed, and the inside of the sealed space is decompressed to reduce the sensitization. An X-ray imaging apparatus for performing X-ray imaging in a state in which paper and a film are in close contact with each other, wherein a front support member is made of an X-ray low-absorbing material, and is detachably attached to the X-ray generation side of the front support member. An X-ray imaging apparatus, wherein a grid is arranged. 3. The X-ray imaging apparatus according to claim 2, wherein the front support member is a carbon fiber. 4. The thickness of the support member on the front side is 2.5 mm.
The X-ray imaging apparatus according to claim 2, wherein the value is less than. 5. The X-ray imaging apparatus according to claim 1, further comprising an X-ray detection unit for controlling an exposure amount of the film behind the fed film. 6. The X-ray imaging apparatus according to claim 6, wherein an X-ray shielding member is disposed behind said X-ray detecting means. 7. The method of claim 1 Symbol of the grid was breastplate
X-ray imaging apparatus of the placement. 8. At least one of a pair of support members.
With an intensifying screen, and feed the film between the support members.
To seal the space between the support members and the closed space.
With the inside depressurized and the intensifying screen and film in close contact
An X-ray imaging apparatus for performing X-ray imaging, wherein a front support portion is provided.
The material is made of a low X-ray absorbing material, and the X-ray
A grid is placed on the source and the grid is used as a breastplate
An X-ray imaging apparatus characterized in that: