JPH05161638A - X-ray diagnosing device - Google Patents

Abstract

PURPOSE:To provide the X-ray diagnosing device which executes slit scan capable of obtaining a high-quality X-ray image without generating local density differences or unphotographed parts. CONSTITUTION:This slit scan system has a slit plate for converging X-rays, irradiates a testee body with the X-rays while moving the slit plate and obtains the X-ray image by the X-rays transmitted through the testee body. The slit plate consists of a lead plate PB having slits 3a, 3b, 3c at least one of while is penetrated through and a carbon fiber reinforced plastic plate CFRP 2 which is joined to at least one of the front surface and rear surface of the lead plate PB, reinforces the lead plate PB and consists of a material allowing the transmission of the X-rays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diagnostic apparatus for slit scanning.

[0002]

2. Description of the Related Art When obtaining internal information of a subject by the difference in X-ray absorption coefficient when the X-ray passes through the subject, a part of the X-rays passing through the subject is scattered and the scattered X-rays are scattered. Is X
When it enters an X-ray image receiving system including a line film, an image intensifier (II), a TV camera, etc., the image quality of the image deteriorates. A slit scan has come to be performed for the purpose of removing the scattered X-rays. An X-ray diagnostic apparatus that performs a slit scan includes an X-ray output system and a subject in addition to the components that are usually provided in the X-ray diagnostic apparatus, that is, the components that form the X-ray output system and the X-ray image receiving system. Slit plate provided between the subject and the X
It is provided with a slit plate provided between the line image receiving system and a moving means for interlockingly moving the slit plate with respect to the subject.

FIG. 4 is a sectional view of a conventional slit plate, and FIG. 5 is a plan view. The slit plate has a three-layer structure in which a lead plate PB, which is an X-ray shielding base material, is sandwiched between two carbon fiber reinforced plastic plates C1 and C2, and slits S1 at regular intervals penetrating from the front surface to the back surface, It has S2 and S3. The number of slits may be one, but it is desirable to provide a plurality of slits in order to shorten the photographing time.

Here, it is the lead plate P that actually shields the X-rays.
Since it is B, the purpose of the slit plate for narrowing down the X-ray is achieved by the lead plate PB having a slit. However, since the lead plate PB is very flexible, the lead plate PB alone is deformed at the time of transportation or when it is fixed to the workbench, and it is necessary to correct the deformation each time, and the work efficiency is very poor. Therefore, first, in order to improve work efficiency, the lead plate PB is sandwiched and joined by two carbon fiber reinforced plastic plates C1 and C2 to increase the rigidity of the slit plate.

The accuracy of the slit of the slit plate used below is the accuracy of the width Lw of the slit and the accuracy of the pitch Lp between one slit and the other slits adjacent thereto (hereinafter referred to as "slit pitch") Lp. I will.

Next, the slit scan method will be described.
The slit precision of the slit plate used below is the precision with respect to the width Lw of the slits and the interval between the slits (hereinafter referred to as “slit pitch”) Lp. The X-ray beam emitted from the X-ray output system first has slits S1, S of the slit plate provided on the X-ray output system side.
2. Squeezed according to the shape of S3. This X-ray beam irradiates the subject, passes through the subject, and is then narrowed down again according to the shape of the slit of the slit plate provided on the X-ray image receiving system side. The X-ray image receiving system receives only the narrowed X-ray beam. As a result, most of the scattered X-rays are blocked by the slits, and the X-ray image receiving system is scattered X-rays.
Only an X-ray beam with few lines can be received, and an X-ray image with good image quality can be obtained. Here, the imaging range of the X-ray image with good image quality is a relatively narrow range limited by the slits of the two slit plates. Therefore, in order to obtain a wide range of X-ray images, it is necessary to move each of the two slit plates at the same time.

When the slit plate is provided with a plurality of slits, the accuracy of this movement must be particularly improved. Here, the slit plate P shown in FIG.
The amount of movement during the slit scan must accurately match the slit pitch Lp. That is,
When the amount of movement does not match the slit pitch Lp, there is a range in which images are superimposed and images are not taken, and as a result, there is a local difference in grayscale in the X-ray image, or an unimaged part. Occurs, and the image quality of the X-ray image deteriorates. The details of the slit scan are Japanese Patent Application No. 1-1538.
No. 68 is shown.

As described above, the accuracy of the movement amount of the slit plate has a great influence on the image quality of the X-ray image of the slit scan, but in addition, the degree of the slit accuracy of the slit plate also has a great influence. .. If this slit accuracy is low, the local difference in light or shade or an unphotographed portion will occur in the X-ray image, similarly to the influence of the accuracy of the movement amount on the image quality. The conventional slit accuracy was poor for the following reasons.

Deterioration of the slit accuracy often occurs when the slit plate is manufactured. As described above, since the lead plate is very flexible, there is a high possibility that the lead plate will be deformed when it is transported or fixed on a workbench as it is. Therefore, the lead plate is sandwiched and joined by two carbon fiber reinforced plastic plates before slit cutting to enhance the rigidity of the slit plate.
The joining is performed by sandwiching an adhesive sheet between the lead plate and each of the two carbon fiber reinforced plastic plates and applying high pressure from both sides. Next, the slit plate is fixed by pressing it on a cutting table, and a slit is formed by cutting the slit plate with a cutting blade and penetrating the slit plate to obtain a slit plate. Here, when the lead plate and the two carbon fiber reinforced plastic plates are pressed under high pressure, stress is generated inside the slit plate. This stress remains inside the slit plate, and after cutting through the slit, the slit plate is distorted under the influence of the internal residual stress. Further, since distortion and vibration occur when the slit is cut by the cutting blade, it is difficult to accurately form the slit at a predetermined position. The distortion and vibration that occur when cutting the slits are particularly likely to occur when cutting the carbon fiber reinforced plastic plate. Due to this distortion and vibration, the slit precision of the slit plate is inevitably reduced.

As described above, the accuracy of the slits of the slit plate is low, so that there is a problem that a local contrast difference or an unphotographed portion occurs in the X-ray image obtained in the slit scan. Further, there is a problem that the cutting blade is extremely worn when cutting the carbon fiber reinforced plastic plate. Furthermore, since the carbon fiber reinforced plastic plate has high rigidity, it is very difficult to cut, and therefore it took a long time to form the slit.

[0011]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an X-ray diagnostic apparatus for performing slit scan capable of obtaining a high-quality X-ray image in which no local contrast difference or an unphotographed portion does not occur. It is to be.

[0012]

An X-ray diagnostic apparatus according to the present invention has a slit plate that narrows down X-rays, irradiates the subject with X-rays while moving the slit plate, and transmits the subject. An X-ray diagnostic apparatus of a slit scan type for obtaining an X-ray image by the X-ray, wherein the slit plate has an X-ray shield plate having at least one penetrating slit, and front and back surfaces of the X-ray shield plate. And a reinforcing plate made of a material which transmits X-rays and which is joined to at least one surface to reinforce the X-ray shielding plate.

[0013]

According to the present invention, the slit accuracy of the slit plate can be improved, and a high-quality X-ray image can be obtained which does not cause a local density difference or an unphotographed portion.

[0014]

Embodiments will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of an X-ray diagnostic apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the X-ray diagnostic apparatus according to one embodiment of the present invention is constructed as follows. First, the X-ray tube 1 that emits X-rays toward the subject 8 is provided. X-rays emitted from the X-ray tube 1 and transmitted through the subject 8 are X-rays.
As a line image, it is incident on the X-ray film 9 arranged so as to face the X-ray tube 1 with the subject 8 as the center. Instead of the X-ray film 9, an X-ray receiving system including an image intensifier, a TV camera, etc. may be used. The slit plate 3 is provided between the X-ray tube 1 and the subject 8 and the subject 8 and the X-ray.
The slit plate 4 is provided between the linear film 9 and the linear film 9, and the slit plate 3 and the slit plate 4 are parallel to each other. Further, the slit plate 3 has slits 3a,
3b and 3c, the slit plate 4 is slit 4a, 4
It has b and 4c.

The control unit 7 supplies an X-ray bombardment timing signal to the high voltage controller 2 and a movement signal to the drive units 5 and 6,
Controls the entire system. The high voltage controller 2 applies a high voltage to the X-ray tube 1 according to the X-ray bombardment timing signal input from the control unit 7. The drive unit 5 translates the slit plate 3 in the direction of the arrow according to the movement signal input from the control unit 7. The drive unit 6 translates the slit plate 4 in the direction of the arrow in response to the movement signal input from the control unit 7. The position detector 10 detects the position of the slit plate 3 and supplies the position signal to the high voltage controller 2.
If the slit plate 3 is not in the proper position, the position signal will stop the supply of high voltage from the high voltage controller 2 to the X-ray tube 1.

Here, the control unit 7 controls the drive unit 5 and the drive unit 6 as follows. Slit 3 of slit plate 3
The moving speed of the slit plate 3 so that the straight line connecting the center of a (3b, 3c) and the center of the slit 4a (4b, 4c) of the slit plate 4 always passes through the tube focus position (not shown) of the X-ray tube 1. And the moving speed of the slit plate 4 are controlled. By this control, scattered X-rays can be shielded. This is for the following reason. The ratio between the slit pitch of the slit plate 3 and the slit pitch of the slit plate 4 is calculated from the tube focus position by the slit plate 3
This is because the slit pitch is set in advance so as to match the ratio of the distance from the tube focus position to the distance from the tube focus position to the slit plate 4. Similarly, slit plate 3
Similarly, the ratio of the slit width to the slit width of the slit plate 4 is made to match the ratio of the distance from the tube focus position to the slit plate 3 and the distance from the tube focus position to the slit plate 4. Next, the configurations of the slit plates 3 and 4 will be described in detail.

FIG. 2 is a plan view of the slit plate 3, and FIG. 3 is a sectional view of the slit plate 3. The slit width and the slit pitch of the slit plate 4 are set according to the ratio of those of the slit plate 3 and the distance from the above-mentioned tube focus position. Since the slit plate 3 and the slit plate 4 are the same except for the slit width and the slit pitch, the slit plate 3
Will be described, and description of the slit plate 4 will be omitted. As shown in FIG. 3, the slit plate 3 has a lead plate PB that shields X-rays from carbon fiber reinforced plastic plate (hereinafter referred to as “CFRP”) 1 and CF.
It has a three-layer structure sandwiched between RP2. Slits 3a, 3b and 3c each having a predetermined slit width Lw and a slit length L are arranged on the lead plate PB and the upper CFRP1 (on the side of the X-ray tube) with a predetermined gap, that is, a slit pitch Lp. However, CFRP2 on the lower side (X-ray film side) is a flat plate having no slit. Here, since the CFRP 2 does not have a slit, the slits 3a, 3b, 3c of the slit plate 3 are not through holes, and CFRP2 exists on the bottom surface of the slit, but CFRP2 has very good X-ray transparency. , The intensity of X-rays is not extremely reduced. This slit plate can be produced by using a conventional slit cutting device whose cutting depth is simply adjusted so as not to cut the CFRP 2. CFRP2
Lead plate PB and two CFRP to prevent slits
1, CFRP2 and the stress generated inside when it is pressed at high pressure will not distort the slit plate after cutting the slit, and since CFRP2 does not have to be cut further, there is no strain when cutting with the cutting blade. And the occurrence of vibration can be suppressed. Further, the abrasion of the cutting edge can be reduced by not cutting the lower carbon fiber reinforced plastic plate, and the slit forming time can be shortened because the carbon fiber reinforced plastic plate is not cut.

Next, the operation of the apparatus of this embodiment will be described. The control unit 7, which has received an instruction to start imaging from a console (not shown), supplies an X-ray bombardment timing signal to the high-voltage controller 2 and a movement signal to the drive units 5 and 6. The high voltage controller 2 applies a high voltage to the X-ray tube 1 according to the X-ray bombardment timing signal input from the control unit 7, and the X-ray tube 1 starts emitting X-rays. Further, in synchronization with the start of X-ray emission, the drive unit 5 translates the slit plate 3 in the direction of the arrow at a moving speed corresponding to the movement signal input from the control unit 7, and the drive unit 6 also inputs from the control unit 7. The slit plate 4 is moved in parallel in the direction of the arrow at a moving speed according to the moving signal. Here, as described above, the straight line connecting the center of the slits 3a (3b, 3c) of the slit plate 3 and the center of the slits 4a (4b, 4c) of the slit plate 4 is always the tube focus (not shown) of the X-ray tube 1. Since the moving speed of the slit plate 3 and the moving speed of the slit plate 4 are controlled so as to pass the position, scattered X-rays can be shielded. The slit plate 3 and the slit plate 4 move the length of each slit pitch and stop. In synchronization with the stop of the slit plates 3 and 4, the high voltage controller 2 stops the application of the high voltage to the X-ray tube 1 under the control of the controller 7 and stops the emission of X-rays. By the above-described operation, a high-quality X-ray image without a local gray level difference or an unphotographed portion can be obtained.

The present invention is not limited to the above embodiment. For example, the slit plate has a three-layer structure in which a lead plate is sandwiched between two carbon fiber reinforced plastic plates, but a two-layer structure of a lead plate with slits and a carbon fiber reinforced plastic plate without slits is also sufficient. There is no limitation to the above three-layer structure as long as it can maintain sufficient rigidity. Further, in the above embodiment, the two slit plates are arranged so as to sandwich the subject, but the slit plate on the X-ray film side may be provided.

[0021]

As described above, according to the present invention, the slit scan X which can obtain a high-quality X-ray image in which no local contrast difference or an unphotographed portion does not occur is performed.
A line diagnostic device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the configuration of an X-ray diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the slit plate shown in FIG.

FIG. 3 is a sectional view of the slit plate shown in FIG.

FIG. 4 is a sectional view of a conventional slit plate.

FIG. 5 is a plan view of a conventional slit plate.

[Explanation of symbols]

1 ... X-ray tube, 2 ... High-voltage controller, 3, 4 ... Slit plate, 3a, 3b, 3c, 4a, 4b, 4c ... Slit,
5, 6 ... Drive unit, 7 ... Control unit, 8 ... Subject, 9 ... X-ray film, 10 ... Position detector, PB ... Lead plate, CFRP1,
CFRP2 ... Carbon fiber reinforced plastic plate, Lw ... Slit width, Lp ... Slit pitch.

Claims (1)

[Claims] 1. A slit plate that narrows down X-rays, and X-rays are applied to a subject while moving the slit plate.
In a slit scan type X-ray diagnostic apparatus that obtains an X-ray image by irradiating a ray and transmitting the X-ray through the subject, the slit plate includes an X-ray shield plate having at least one penetrating slit, and An X-ray diagnostic apparatus, comprising: a reinforcing plate that is joined to at least one of a front surface and a back surface of the X-ray shielding plate to reinforce the X-ray shielding plate and is made of a material that transmits X-rays.