JPH0956714A - X-ray tomographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray tomographic apparatus capable of giving a distinct and plane tomogram SOLUTION: A tomographic apparatus 51 comprises an X-ray source 6 and X-ray film cassette 7 capable of performing a curved surface tomography and plane tomography are supported by a supporting arm 4 as interposing an object between them. The supporting arm 4 is fixed to a substrate base 1 through a linear sliding mechanism 8 which straightly moves the supporting arm 4 in the direction perpendicular to the longitudinal direction of the supporting arm 4, revolving mechanism 3 and an X-Y table 2 which horizontally moves the supporting arm 4. A gird 61 formed by arranging plural plate members for removing scattered X-ray is arranged on an opening 7n of a switching plate 7h installed between a housing 7d supporting X-ray film cassette 7 and the X-ray film cassette 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tomographic X-ray apparatus used in plane tomography in dentistry, otolaryngology and the like.

[0002]

2. Description of the Related Art In recent years, a tomographic X-ray apparatus for performing plane tomography of the head, face and chin of a human body has been developed.

In plane tomography, a part of the X-ray flux emitted from the X-ray source is scattered by molecules constituting the subject when passing through the subject, and scattered X-rays whose traveling direction is changed. Becomes Since the traveling direction of the scattered X-rays is changed, the positions on the X-ray detecting means to which the X-rays should be incident, that is, the respective positions of the focus to which the X-rays of the X-ray source are irradiated and the region of the subject to be imaged. A straight line connecting to and enters at a position other than the position where it intersects with the X-ray detection means.

Thus, when the scattered X-rays enter the X-ray detecting means, the X-rays that have passed through different parts of the subject enter the same position on the X-ray detecting means.
It causes blurring of the X-ray image taken.

[0005]

A conventional slice X for the purpose of taking a plane slice for dentistry or otolaryngology.
The radiographic apparatus does not have any means for preventing scattered X-rays from entering the X-ray detecting means, and therefore a clear plane tomographic image cannot be obtained.

An object of the present invention is to provide a tomographic X-ray imaging apparatus capable of obtaining a clear plane tomographic image.

[0007]

According to the present invention, there is provided an X-ray generator and an X-ray detecting means which sandwich an object, and a plane which is provided between the object and the X-ray detecting means and through which an X-ray passes. An X-ray receiving shape setting plate having an opening for tomography is provided, and the X-ray generator and the X-ray detecting means are moved in parallel and in opposite directions to a preset plane tomographic plane in the subject. In the tomographic X-ray imaging apparatus that causes the plane tomography to be performed by rotating or swiveling, a grid unit that removes scattered X-rays is provided in the planar tomography opening. According to the present invention, in plane tomography using a tomographic X-ray imaging apparatus, first, the X-ray generator and the X-ray detection means are planes on which the straight line connecting the X-ray generator and the X-ray detection means is the subject to be imaged. The X-ray generator is moved to a position perpendicular to the tomographic plane, and then, while being irradiated with X-rays by the X-ray generator, the X-ray generator is linearly moved in a direction parallel to the plane tomographic plane to be imaged. The X-ray detection means is linearly moved in the direction opposite to the direction in which the X-ray generator is moved. Alternatively, the X-ray generator and the X-ray detection means are
Rotate the plane tomographic plane in the subject. At this time,
The X-ray flux passing through the subject is incident on the X-ray detection means via the grid means. Further, the following curved surface tomography function may be added to the tomography. The curved surface tomography by the tomography apparatus is performed by rotating the X-ray generator and the X-ray detection means around the subject while the X-ray generator irradiates the X-ray. At this time, the X-ray detection means is moved in a direction tangential to the direction in which the X-ray detection means is turned in a direction opposite to the turning direction at a moving speed corresponding to the turning speed of the X-ray generator and the X-ray detection means. . Therefore, since the plane tomography opening of the X-ray receiving shape setting plate provided between the subject and the X-ray detecting means is provided with the grid means for removing scattered X-rays, it becomes clear by the plane tomography. A plane tomographic image can be obtained.

Further, the present invention is characterized in that the grid means comprises a plurality of plate members arranged in parallel with the traveling direction of the passing X-rays at a predetermined interval, and the grid means comprises X-axis.
It is characterized in that it is arranged at a predetermined distance from the line detection means to the X-ray generator side. According to the present invention, the grid means is provided with an X
When the ray bundle is incident, the non-scattered passing X-rays that have passed through the subject included in the X-ray bundle pass through the grid means and become X.
The scattered X-rays that have entered the ray detection means, are scattered by the subject, and have changed their traveling direction, are incident on the surface of the plate member of the grid means because the traveling direction has been changed. The scattered X-rays incident on the surface of the plate member are absorbed and scattered by the plate member and removed. Therefore, since the grid means is formed by arranging a plurality of plate members at a predetermined interval,
It is possible to minimize the reduction of X-rays that occur when passing X-rays to be passed through the grid means and efficiently remove scattered X-rays. Also, the grid means is X
Since it is arranged with a predetermined distance from the line detecting means, it is possible to prevent the shadow of the grid means from appearing in the plane tomographic image detected by the X-ray detecting means.

[0009]

1 is a partially cutaway side view showing the configuration of a dental or otolaryngological tomographic X-ray apparatus 51 according to an embodiment of the present invention, and FIG. 2 is a tomographic X-ray apparatus. Device 5
1 is a partially cutaway perspective view showing the configuration of FIG. 1, and FIG. 3 is a partially cutaway perspective view showing the partial configuration of a tomographic X-ray imaging apparatus 51.

The tomographic X-ray apparatus 51 comprises a base 1 and an XY unit.
Table 2, swivel mechanism 3, support arm 4, X-ray source 6, X
The linear film cassette 7 and the linear slide mechanism 8 are included. The X-ray generator 6 and the X-ray film cassette 7 are supported by the support arm 4 so as to face each other with the subject in between. The X-ray generator 6 and the X-ray film cassette 7 thus supported are swung by the swivel of the support arm 4 by the swivel mechanism 3, and the swivel center position of the support arm 4 is adjusted by the XY table 2. . Therefore, the support arm 4 is supported by the base 1 via the XY table 2 and the turning mechanism 3. The linear slide mechanism 8 linearly moves the support arm 4 in a direction perpendicular to the longitudinal direction of the support arm 4, and the X-ray source 6 is moved along with the linear movement of the support arm 4. X-ray film cassette 7
Accordingly, as described later, the linear movement is performed in the direction opposite to the direction in which the support arm 4 is moved. The X-ray source 6 and the X-ray film cassette 7 are attached to both ends of the support arm 4 so as to face each other. On the X-ray source 6 side of the X-ray film cassette 7, a switching plate 7h is provided as a light-receiving shape setting plate having a grid 61 described later. A predetermined space is provided between the X-ray film loaded in the X-ray film cassette 7 and the switching plate 7h.

The XY table 2 includes an X-axis motor 2a for adjusting the position in the X-axis direction, a guide mechanism 2b, a Y-axis motor 2c for adjusting the position in the Y-axis direction, and a guide mechanism 2.
d and a slide member 2e, etc., each motor 2
The slide member 2e moves in the XY plane in response to the driving of a and 2c, and the position of the turning mechanism 3 attached to the lower portion of the slide member 2e is controlled. The above-mentioned guide mechanisms 2b and 2d are composed of rollers 2f and 2g that are rotatable by bearings, and guide frames 2h and 2j that have guide grooves for these rollers.

The turning mechanism 3 is a belt mechanism 3 including a turning motor 3a, a pulley for transmitting the rotation, and a belt.
b and the revolving structure 3 around which the belt mechanism 3b is wound.
The revolving unit 3c is rotatably supported by the slide member 2e of the XY table 2 via a bearing 3d. Therefore, the motor 3a
The revolving unit 3c revolves by driving the
The support arm 4 attached to the lower part of c also pivots similarly.

The linear slide mechanism 8 includes a drive motor 8
a and a rotation screw shaft 8c for transmitting its rotation via a belt mechanism 8b and a guide mechanism 8d. The drive motor 8a is fixed to the support arm 4, the moving screw shaft 8c is rotatably attached to the support arm 4, and the guide mechanism 8d is a guide frame 8e attached to the revolving structure 8c and the support arm 4. The slide member 8g is integrally formed on the upper surface of the above and is supported by the guide frame 8e via the roller 8f. Further, a connecting body 8h is integrally fixed to the lower surface of the guide frame 8e, and a moving screw shaft 8c is screwed into a female screw body 8j provided at the lower end of the connecting frame 8h. The female screw body 8j is configured to move relatively in the axial direction.

Therefore, by rotating the entire linear slide mechanism 8 below the guide frame 8e and the support arm 4 by the rotating mechanism 3, the moving direction by the guide frame 8e is set to be parallel to an arbitrary plane tomographic plane. It is possible,
By driving the drive motor 8a in this state,
The support arm 4 can be linearly moved along the guide frame 8e (in the example of FIG. 1, in the direction perpendicular to the paper surface).

The support arm 4 is provided with a rotation motor 6a for rotating the X-ray source 6 with respect to the support arm 4, and the X-ray flux is always X-ray linked with the movement of the support arm 4. It is configured to rotate about a vertical direction so that the film cassette 7 is irradiated with the light.

On the X-ray film cassette 7 side, a housing 7 supported by a support arm 4 by a slide mechanism 7a.
The housing 7d is provided with a holder 7g supported by a slide mechanism 7e and moved by a drive motor 7f. The X-ray film cassette 7 is housed in the holder 7g. A belt mechanism 7 for transmitting the rotation of the drive motor 8a is provided on the upper portion of the housing 7d.
b and a moving screw shaft 7c that rotates by this are provided, and a sliding member 7i fixed to the housing 7d is screwed onto the moving screw shaft 7c. Therefore, when the drive motor 8a is driven and the support arm 4 moves,
In conjunction with this, the slide member 7e, that is, the housing 7d, moves together with the X-ray film cassette 7 in the direction opposite to the movement of the support arm 4.

Since the tomographic X-ray imaging apparatus 51 is an apparatus capable of performing curved surface tomography and plane tomography, the X-ray irradiation field shape irradiated from the X-ray source 6 and the X-ray film cassette 7 side light receiving shape are used. Need to be changed according to the purpose. Therefore, the X-ray source 6 is provided with an irradiation field shape switching plate 6b and its drive motor 6c, and the X-ray film cassette 7 side is provided with a switching plate 7h and its drive motor 7j as a light receiving shape setting plate. Has been.

In FIG. 2, the support unit 1a incorporates an X-axis motor 2a of the XY table 2, an X-axis mechanism such as a guide mechanism 2b, and a swivel mechanism 3.
A fixing mechanism 1b for fixing the patient's head is provided between the X-ray source 6 and the X-ray film cassette 7, and a patient chair 1c is provided below the fixing mechanism 1b. The height of the base 1 can be freely adjusted according to the sitting height of the patient sitting on the chair 1c.

FIG. 4 shows a housing 7d and a holder 7g.
It is a front view when seeing from the X-ray source 6 side. Similarly, FIG. 5 is a front view of the housing 7d and the holder 7g.
The housing 7d and the switching plate 7h are formed of an X-ray shielding material, and the housing 7d has a rectangular opening 7m, and the switching plate 7h has a wide rectangular opening for plane tomography. A narrow and narrow rectangular opening 7p for curved section is provided on the front, respectively, and the holder 7g and the X-ray film cassette 7 held by the holder 7g are driven by the motor 7f, and the switching plate 7h is driven by the motor 7j. Each of them is moved in the lateral direction of FIGS.

A grid 6 for removing scattered X-rays incident on the X-ray film cassette 7 is provided in the opening 7n of the switching plate 7h.
1 is provided. FIG. 4 shows the opening 7m of the housing 7d.
The opening 7n of the switching plate 7h is located at a position facing the motor 7
The state at the time of plane tomography moved by driving of f is shown. On the other hand, FIG. 5 shows a state at the time of curved surface tomography in which the opening 7p is moved to a position facing the opening 7m.

FIG. 6 is a perspective view showing the structure of the grid 61 provided in the opening 7n of the switching plate 7h. The grid 61 formed of a material such as aluminum is composed of a plurality of thin plate members 61b and a frame 61a. The plate members 61b are arranged inside the frame 61a in parallel with each other at a predetermined arrangement pitch P1, for example, 0.2 mm. The depth D1 of the grid 61, that is, the thickness D1 in the longitudinal direction of the support arm 4 is set to 1 mm, for example.

As the arrangement pitch P1 is made smaller and the thickness D1 is made thicker, the scattered X-rays can be removed more reliably, but the X-rays to be passed through the grid 61 are also reduced accordingly. Array pitch P1
And the thickness D1 needs to be set to an appropriate value.

In the grid 61 thus constructed, the opening of the switching plate 7h is arranged so that the surface of each plate member 61b is parallel to the longitudinal direction of the support arm 4 and parallel to the vertical direction. It is fitted and fixed inside 7n.

Although it has been assumed here that the switching plate 7h and the grid 61 are separate bodies, the switching plate 7h and the grid 6 are separate.
1 may be integrally formed.

FIG. 7 is a block diagram showing the electrical construction of the drive circuit of the tomographic X-ray apparatus 51. The drive circuit of the tomographic X-ray imaging apparatus 51 includes a control unit 11 including a CPU (central processing unit), a control panel 12, an X-ray generation circuit 13,
It is provided with drive circuits 21 to 28 for various motors and sensors 33 to 38 for position and angle of each part. When the operator operates the control panel 12 to input a command for instructing the imaging mode, the control unit 11 sends a predetermined signal to each motor drive circuit 2 in accordance with the mode of the plane tomography or the curved tomography.
It is output to 1-28. As a result, each motor is driven, and the results are detected by the sensors 33 to 38 and field-backed to the control unit 11.

Curved surface tomography by the tomographic X-ray apparatus 51 having the above-described structure is performed as follows. The case of performing curved surface tomography of the patient's upper and lower jaws will be described here. First, the patient is seated on the chair 1c, and the head of the patient is fixed by the fixing mechanism 1b. Next, the operator uses the control panel 21 to perform the tomographic X-ray imaging apparatus 5
1 is instructed to start curved tomography, the tomography apparatus 51 starts imaging.

When imaging is started, X-ray is emitted by the X-ray source 6.
The support arm 4 is swung by the swivel mechanism 3 while the ray bundle is being irradiated, and along this, the straight line connecting the X-ray source 6 and the X-ray film cassette 7 is substantially perpendicular to the left or right end of the upper and lower jaws. X-ray source 6 and X from the intersecting state until the state where the intersecting state is substantially perpendicular to the right or left end portion
The linear film cassette 7 is rotated. The XY table is maintained so that the direction of the straight line connecting the X-ray source 6 and the X-ray film cassette 7 is substantially perpendicular to the arrangement direction of the dental arch along with the rotation of the support arm 4. The pivot center of the support arm 4 is moved by 2.

With the turning of the support arm 4 as described above,
The motor 7f is driven, and the X-ray film cassette 7 is moved at a moving speed corresponding to the turning speed of the support arm with respect to the opening 7p provided in the switching plate 7h, for example, from the state shown by the solid line in FIG. It is moved to the state indicated by.

The plane tomography is performed as follows. In addition, here, the case where the plane tomographic planes of the upper and lower jaws of the patient are imaged will be described. As in the case of the curved surface tomography described above, when the head of the patient is fixed by the fixing mechanism 1b, the support arm 4 is swung by the swivel mechanism 3, and a straight line connecting the X-ray source 6 and the X-ray film cassette 7 is formed. ,
The upper and lower jaws are rotated so that they intersect perpendicularly to the plane tomographic planes to be imaged. At this time, the position of the support arm 4 in the longitudinal direction of the support arm 4 with respect to the patient's head is X.
-Adjusted by Y table 2 to appropriate position.

When the longitudinal direction of the support arm 4 is set to be perpendicular to the plane slice planes of the upper and lower jaws to be imaged in this way, the irradiation of the X-ray flux by the X-ray source 6 is started and at the same time. The motor 8a is driven. When the motor 8a is driven, the support arm 4 moves with respect to the base 1.
Is linearly moved in a direction perpendicular to the longitudinal direction of X, and along with this, the X-ray source 6 is also moved. Further, the drive of the motor 8a is transmitted to the moving screw shaft 7c by the belt mechanism 7b, which causes the X-ray film cassette 7 and the holder 7g to move.
Is moved in a direction opposite to the direction in which the support arm 4 is moved with respect to the support arm 4. Such X-ray sources 6 and X
With the movement of the X-ray film cassette 7, the direction of the X-ray source 6 is rotated by the motor 6a so that the X-ray flux to be emitted is emitted in the same position of the X-ray film cassette 7. At this time, the X-ray flux that has passed through the patient's upper and lower jaws enters the X-ray film cassette 7 via the grid 61.

FIG. 8 shows an X-ray source 6 and an X-ray film cassette 7 for plane tomography by the tomography apparatus 51.
It is a figure which shows operation | movement. The plane tomography by the plane tomography apparatus 51 is performed as follows. Note that here, a case is described in which the front-rear surface in the center of the front tooth portion is set as the plane tomographic plane L to be imaged. In FIG. 8, the subject P is the patient's head. First, the patient is seated on a chair (not shown), and the X-ray source 6 and the X-ray film cassette 7 are placed.
Fix its head between and. The position of the support arm 4 in the horizontal plane is the XY table 2 and the orientation thereof is the swivel mechanism 3 so that the longitudinal direction of the support arm 4 coincides with the center line AA orthogonal to the plane tomographic plane L. adjust.

Here, since the movement direction of the support arm 4 must be parallel to the plane tomographic plane L, the adjustment of the angle of the support arm 4 is particularly important, but the angle is the turning mechanism 3.
The adjustment work is easy because there is no need to orient the patient in a particular direction, as it can be set arbitrarily.

The so-called X-ray image magnification is determined by the ratio of the distance D1 from the X-ray source 4 to the X-ray film cassette 7 and the distance D2 from the X-ray source 6 to the plane tomographic plane L.
The position of the support arm 4 may be set so that a desired enlargement ratio can be obtained.

During photographing, the X-ray source 6 moves from a position indicated by a solid line slightly apart from the center line AA to a target position indicated by a broken line beyond the center line AA as indicated by an arrow I. The linear slide mechanism 8 linearly moves the support arm 4 as described above. In conjunction with this, the X-ray film cassette 7 is translated in the opposite direction from the solid line position to the broken line position as indicated by arrow J, and the X-ray flux emitted from the X-ray source 6 in response to this movement. The X-ray source 6 is rotated so that the center of the X-ray always passes through the center point C of the plane tomographic plane L and is incident on the same position of the X-ray film cassette 7.

As a result, the image of the same portion of the plane tomographic plane L is always incident on the film in the X-ray film cassette 7 at the same position, while the image of the portion other than the plane tomographic plane L is incident on the film surface. Is moved to form a blurred image, and an X-ray image N of the plane tomographic plane L is captured. It should be noted that a large amount of movement is desirable in order to obtain a clear X-ray image. Further, the moving range does not necessarily have to be a control with respect to the center line AA.

The irradiation field shape of the X-ray source 6 and the light-receiving shape of the X-ray film cassette 7 are the shape for plane tomography by the irradiation field shape switching plate 6b driven by the motor 6c and the switching plate 7h. And size are automatically switched.

Further, each time one plane tomography is completed, the motor 7f is driven at a predetermined pitch, and the holder 7g and the X-ray film cassette 7 are moved with respect to the housing 7d, whereby one X-ray film is formed. It is possible to take multiple plane tomographic images.

In the plane tomography described above, the grid 61
When the X-ray flux that has passed through the subject is incident on, the transmitted X-rays, which are included in the X-ray flux and have passed through the subject without being scattered, are detected by the plate member 61b of the grid 61 in the longitudinal direction of the support arm 4, that is, the traveling direction of the passing X-ray. Since they are provided in parallel, they enter the X-ray film cassette 7 without being removed by the grid 61. On the other hand, the scattered X-ray scattered by the subject and changed in traveling direction is incident on the surface of the plate member 61b of the grid 61 because the traveling direction deviates from the longitudinal direction of the support arm 4 due to scattering. The scattered X-rays incident on the surface of the plate member 61b are
Are absorbed and scattered by and are removed.

Therefore, since the grid 61 for removing scattered X-rays is provided between the subject and the X-ray film cassette 7, a clear plane tomographic image can be obtained by plane tomography.

The grid 61 includes a plurality of plate members 61b.
Are formed by being arranged at a predetermined arrangement pitch P1 in parallel with the traveling direction of the passing X-rays, the reduction amount of the passing X-rays to be passed can be suppressed to the minimum limit, and the scattered X-rays can be efficiently removed. it can.

Further, the switching plate 7 provided with the grid 61
Since a predetermined space is provided between h and the X-ray film filled in the X-ray film cassette 7, the shadow of the grid 61 is prevented from appearing in the plane tomographic image recorded on the X-ray film. can do.

In the above-mentioned tomographic X-ray apparatus 51,
The grid 61 is provided such that the surface of the plate member 61b is parallel to the vertical direction. However, if the surface of the plate member 61b is parallel to the longitudinal direction of the support arm 4, the grid 61 is not limited to parallel to the vertical direction. Instead, it may be diagonal.

FIG. 9 is a perspective view showing the structure of a grid 71 provided in a tomographic X-ray apparatus according to another embodiment of the present invention. The grid 71 is provided in the opening 7n of the switching plate 7h, similarly to the grid 61 provided in the tomographic X-ray imaging apparatus 51 of the above-described embodiment. Grid 7
1 is configured to include a frame 71a, and a plurality of vertical plate members 71b and horizontal plate members 71c perpendicularly intersecting each other. The vertical plate members 71b are arranged at an arrangement pitch P2, and the horizontal plate members 71c are arranged at an arrangement pitch P3. Grid 7
The thickness of the first support arm 4 in the longitudinal direction is set to D2.

Here, it is assumed that the light receiving shape switching plate 7h is provided so that each vertical plate member 71b is parallel to the vertical direction and each horizontal plate member 71c is parallel to the horizontal direction.
Since each surface of the vertical plate member 71b and the horizontal plate member 71c may be parallel to the longitudinal direction of the support arm 4, the vertical plate member 71b and the horizontal plate member 71c are inclined obliquely with respect to the vertical direction and the horizontal direction. May be.

In the grid 71 thus constructed,
Since a grid-like grid is formed by a plurality of vertical plate members 71b and horizontal plate members 71c that intersect each other vertically, the scattered X-rays are efficiently removed regardless of the direction in which the X-rays are scattered by the subject. can do.

FIG. 10 is a partially cutaway side view showing the construction of a tomographic X-ray apparatus 51a according to still another embodiment of the present invention. In FIG. 10, portions similar to or corresponding to those of the tomographic X-ray apparatus 51 shown in FIGS. 1 to 8 described above are designated by the same reference numerals. A feature of the tomographic X-ray imaging apparatus 51a is that the housing 7d holding the X-ray film cassette 7 is rotatable with respect to the support arm 4.

In the tomographic X-ray apparatus 51a, the support arm 4 is provided with an X-ray film cassette rotation mechanism 81 for rotating the housing 7d around an axis parallel to the pivot axis of the support arm 4. The X-ray film cassette rotation mechanism 81 is configured to include a gear 81b connected to the housing 7d by a shaft 81c and a motor 81a having a drive gear that meshes with the gear 81b. The motor 81a is controlled so as to interlock with the motor 3a of the turning mechanism 3 described above.

For example, when the support arm 4 is viewed from above,
For example, when the housing 7d is rotated clockwise, the housing 7d is rotated in a direction opposite to the direction in which the support arm 4 is rotated, for example, counterclockwise, so that the X-ray film provided in the X-ray film cassette 7 is removed. The angle is adjusted to be parallel to the plane tomographic plane of the subject.

FIG. 11 is a diagram showing the operations of the X-ray source 6 and the X-ray film cassette 7 during plane tomography by the tomographic X-ray apparatus 51a. The plane tomography by the tomography apparatus 51a is performed as follows. When the head of the subject is fixed between the X-ray source 6 and the X-ray film cassette 7, a straight line connecting the X-ray source 6 and the X-ray film cassette 7 as shown by reference numeral A in FIG. The support arm 4 so that it penetrates the plane tomographic plane L in the subject in an oblique direction.
The position in the horizontal plane is adjusted by the XY table 2, and the orientation is adjusted by the turning mechanism 3. At this time, the grid 61 fitted into the opening 7n of the X-ray film cassette 7 and the switching plate 7h is adjusted by the motor 81a so that the orientation becomes parallel to the plane tomographic plane L.

When the X-ray source 6 and the X-ray film cassette 7 are installed as described above, the X-ray source 6 is rotated by the turning mechanism 3.
And the X-ray film cassette 7 is rotated in the direction of arrow A together with the support arm 4. The X-ray source 6 and the X-ray film cassette 7 are swung from the state A through a state B in which a straight line connecting the X-ray source 6 and the X-ray film cassette 7 penetrates the plane tomographic plane L vertically. 6 and X-ray film cassette 7
The straight line connecting the lines up to and including the state C extending diagonally through the plane tomographic plane L is performed. Along with this turning, the motor 81a is driven and the orientations of the X-ray film cassette 7 and the grid 61 are adjusted so that they are always parallel to the plane tomographic plane L.

In the tomographic X-ray apparatus 51a of the present embodiment, planar tomography is performed by rotating the support arm 4, so that the X-ray source 6 is used as the tomographic X-ray apparatus 51 of the above-described embodiment.
It is not necessary to rotate the motor 6a and the motor 6a is removed. The X-rays operated from the X-ray source 6 are set so as to be always irradiated in the longitudinal direction of the support arm 4, that is, toward the X-ray film cassette 7.

The curved tomography by the tomography X-ray apparatus 51a is performed in the same manner as in the case of the tomography X-ray apparatus 51 of the above-mentioned form, and the description thereof will be omitted.

Therefore, in the tomographic X-ray imaging apparatus 51a, since the plane tomography is performed by rotating the support arm 4, the linear slide mechanism 8 is not required, and the structure of the tomographic X-ray imaging apparatus 51a can be simplified. Therefore, the cost of the device can be reduced.

In each of the above-mentioned embodiments, the X-ray detecting means comprises the X-ray film and the X-ray film cassette, but a known X-ray image sensor may be used as the X-ray detecting means. X which consists of a fluorescent plate that converts X-rays into visible light and a SIT (Silicon Intensified tube) that converts an image on the fluorescent plate into an electric signal with high sensitivity.
X-ray C using semiconductor device instead of X-ray camera and SIT
A CD (Charge Coupled Device) sensor, an X-ray fluorescence multiplier, or the like is used.

Further, as the X-ray detecting means, an X-ray imaging plate for accumulating and storing the X-ray image of the subject can be used. The X-ray images accumulated and stored by the X-ray imaging plate are, for example, ECR (exposure dat) of FCR (Fuji Computed Radiography; trade name).
The X-ray image read out as an electrical digital signal by the a recognizer) is displayed on the display device. Alternatively, the X-ray image read out as an electric signal may be output to the printer so that the printer prints the X-ray image.

[0056]

As described above, according to the present invention, since the grid means for removing scattered X-rays is provided, a clear plane tomographic image can be obtained.

Further, according to the present invention, since the grid means is formed by arranging a plurality of plate members at a predetermined interval, the reduction of the X-rays generated when the passing X-rays to be passed through the grid means is minimized. The scattered X-rays can be removed efficiently as long as possible.

Further, since a predetermined space is provided between the grid means and the X-ray detection means, it is possible to prevent the shadow of the grid means from appearing in the plane tomographic image detected by the X-ray detection means. As a result, a clear plane tomographic image can be obtained.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a configuration of a tomographic X-ray imaging apparatus 51 for dentistry or otolaryngology according to an embodiment of the present invention.

2 is a partially cutaway perspective view showing a configuration of a tomographic X-ray imaging apparatus 51. FIG.

FIG. 3 is a partially cutaway perspective view showing a partial configuration of a tomographic X-ray imaging apparatus 51.

FIG. 4 is a front view of a housing 7d and a holder 7g.

FIG. 5 is a front view of a housing 7d and a holder 7g.

FIG. 6 is a perspective view showing a configuration of a grid 61.

7 is a block diagram showing an electrical configuration of a drive circuit of the tomographic X-ray apparatus 51. FIG.

FIG. 8 is a diagram showing operations of the X-ray source 6 and the X-ray film cassette 7 at the time of plane tomography by the tomography apparatus 51.

FIG. 9 is a perspective view showing a configuration of a grid 71 included in a tomographic X-ray imaging apparatus that is another embodiment of the present invention.

FIG. 10 is a partially cutaway side view showing the configuration of a tomographic X-ray apparatus 51a according to another embodiment of the present invention.

FIG. 11 is a diagram showing the operations of the X-ray source 6 and the X-ray film cassette 7 during plane tomography by the tomographic X-ray apparatus 51a.

[Explanation of symbols]

1 Base 2 XY Table 2a, 2c, 3a, 6a, 6c, 7f, 7j, 8a, 8
1a motor 3 turning mechanism 4 support arm 6 X-ray source 7 X-ray film cassette 8 linear slide mechanism 11 control unit 12 control panel 13 X-ray generation circuit 21-28 motor drive circuit 33-38 sensor 51, 51a tomographic X-ray imaging apparatus 61, 71 grid 61b, 71b, 71c plate member 81 rotation mechanism for X-ray film cassette

Claims (2)

[Claims] 1. An X-ray generator and an X-ray detection means provided to sandwich a subject, and an X-ray having a plane tomography opening provided between the subject and the X-ray detection means and through which X-rays pass. And a line-reception shape setting plate, wherein the X-ray generator and the X-ray detection means are moved in parallel and opposite directions to each other with respect to a preset plane tomographic plane in the subject, or rotated to produce a plane tomographic plane. Tomography X
A tomographic X-ray imaging apparatus, comprising a grid means for removing scattered X-rays in the plane tomography opening. 2. The grid means is constituted by a plurality of plate members arranged in parallel with the traveling direction of passing X-rays at a predetermined interval, and the grid means generates X-rays from the X-ray detection means. The tomographic X-ray apparatus according to claim 1, wherein the tomographic X-ray imaging apparatus is arranged on the apparatus side with a predetermined distance.