JPH0743721Y2 - Cassette holder for dental panoramic X-ray equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a cassette holder of a dental panoramic X-ray imaging apparatus for panoramically taking a tomographic image of a dental jaw region, and particularly to a cassette holder using a flat plate-shaped cassette. Regarding cassette holder.

[Conventional technology]

The dental panoramic radiography system has an X-axis on one end of the horizontal arm.
At the other end of the tube, the cassette holders holding the film cassettes containing the X-ray film are hung so as to face each other, and the horizontal arms of the tube holders are extended horizontally on the arm drive section that extends horizontally from the column. Is rotatably supported. Then, the head of the subject is positioned and arranged between the X-ray tube and the cassette holder,
While rotating the horizontal arm to orbit the X-ray tube and the cassette holder around the subject's head, the film cassette is moved so that the X-rays emitted from the X-ray tube are moved to the patient's tooth jaw. The parts are irradiated from multiple directions, and the transmitted X-rays are sequentially irradiated to each part of the X-ray film through the longitudinal slits of the cassette holder so that a full-jaw tomography is performed.

By the way, as a film cassette, a flexible cassette has been mainly used in the past, and the flexible cassette was loaded on the cylindrical peripheral surface of the film drum to rotate the film drum in synchronism with the orbiting motion of the X-ray tube and the cassette holder. However, in recent years, compared with the case of using a flexible cassette, the adhesion between the X-ray film and the intensifying screen is better, and a flat-plate cassette, which is also excellent in terms of photographic sharpness, is used. 2. Description of the Related Art A dental panoramic X-ray imaging apparatus of a type in which a flat-plate-shaped cassette is linearly moved while being supported by the cassette holder in synchronism with the orbital movement of the tube and the cassette holder is widely used.

[Problems to be solved by the device]

However, since the flat-plate cassette accommodates the X-ray film in a flat state, the dimension in the longitudinal direction (the moving direction of the cassette) is large, and usually 30 cm or more. Moreover, in a vertical posture with the flat-plate-shaped cassette in a horizontal position, a cassette holder having an X-ray shielding plate on the front surface (a surface facing the X-ray tube) is used, for example, the left end of the flat-plate cassette is set to the width of the cassette holder. Align with the position of the vertical slit formed in the center in the direction, start shooting in that state, and shoot while linearly moving the flat cassette to the left in response to the clockwise rotational movement of the horizontal arm. Then, when the right end of the flat cassette reaches the position of the longitudinal slit of the cassette holder, the photographing is finished. Therefore, the moving distance of the flat-plate cassette becomes substantially equal to the dimension in the longitudinal direction thereof, and the length of the space occupied by the flat-plate cassette moving is approximately twice the length of the flat-plate cassette in the longitudinal direction. It will be over 60 cm. Therefore, in order to completely store the flat cassette in the cassette holder during the entire movement of the flat cassette and prevent the flat cassette from being exposed to the outside of the cassette holder, the width dimension of the cassette holder is set to, for example, 60 cm. It is necessary to be above.

However, if such a large cassette holder is hung at one end of the horizontal arm and the horizontal arm is tried to be rotated, the device becomes large in size, and in terms of space,
Also, it is disadvantageous in terms of cost. Furthermore, with the head of the subject placed in a narrow space between the X-ray tube suspended at both ends of the horizontal arm of a limited length and the cassette holder,
The X-ray tube and the cassette holder have to be rotated, but when the cassette holder becomes large, the operator has to use extra nerves in the operation.

For this reason, the width of the conventional cassette holder is as small as possible, and is usually slightly shorter than the size of the flat cassette in the longitudinal direction. Therefore, at the start and at the end of shooting, approximately half of the flat-plate-shaped cassette largely projects from both end surfaces of the cassette holder.

Here, during X-ray imaging, the primary X-rays emitted from the X-ray tube pass through the subject's head, which is the subject, and the transmitted X-rays are transmitted.
The secondary X-rays are scattered from the subject's head when the rays pass through the longitudinal slits of the cassette holder and irradiate the X-ray film in the flat cassette. The scattered X-rays have a wide range of radiation directions, and the scattered X-ray generation state greatly differs depending on individual differences such as the shape and size of the subject's head and imaging conditions. It will be. Therefore, when scattered X-rays are often generated, the X-ray film in the portion of the flat-plate cassette projecting from the side end surface of the cassette holder is sensitive to the scattered X-rays, causing fogging in the image. When the width dimension of the cassette holder is set to be approximately equal to the dimension of the flat-plate cassette in the longitudinal direction, the range will eventually cover almost the entire area of the X-ray film. As a result, there is a problem that the contrast, sharpness, and resolution of the image captured on the film surface decrease.

This invention was made in view of the above circumstances,
In a dental panoramic X-ray imaging apparatus of a type using a flat-plate cassette, scattered X-rays generated during X-ray photography can be incident on the X-ray film surface in the flat-plate cassette without increasing the size of the cassette holder. Preventing is a technical issue.

[Means for Solving the Problems]

In this invention, as a technical means for achieving the above-mentioned object, the cassette holder of the dental panoramic X-ray imaging apparatus is configured as follows.

First, the first configuration of the cassette holder according to the present invention is such that one end of a horizontal arm that is suspended in an arm drive portion that horizontally extends from a column and is rotatably supported in a horizontal plane is The flat cassette is hung so as to face the X-ray source hung at the other end, and the flat-plate cassette is housed in a vertical posture while facing the X-ray source, and the flat-plate cassette is moved in accordance with the rotational movement of the horizontal arm. The X-ray film in the flat cassette is held so as to be linearly moved in the direction, and passes through an elongated slit formed at the center in the width direction of the X-ray shielding plate arranged on the side facing the X-ray source. Dental panorama X with X-ray irradiation
In a cassette holder of a radiographic apparatus, at least both left and right sides of the X-ray shield plate are projected toward the X-ray source.

The X-ray shield plate may be formed to have an arc surface or a flat surface. Furthermore, it is also possible to form the X-ray shielding plate so that the cross-sectional shape thereof is a hook shape.

Further, the X-ray shielding plate is composed of a strip-shaped central shielding plate having a longitudinal slit for passing X-rays, and a pair of left and right shielding plates symmetrically arranged on both left and right sides thereof. Alternatively, the X-ray shielding plate may be formed of a single plate-shaped body, and a vertically long slit that allows passage of X-rays may be formed in the center of the plate-shaped body in the width direction.

Another configuration of the cassette holder according to the present invention is
It is hung by an arm drive section that extends horizontally from the support column, and hangs at one end of a horizontal arm that is rotatably supported in a horizontal plane, facing the X-ray source that is hung at the other end of the horizontal arm. , The flat-plate cassette is faced to the X-ray source and accommodated in a vertical posture, and the flat-plate cassette is held so as to be linearly moved in one direction in accordance with the rotational movement of the horizontal arm. On the opposite side of
An X-ray shielding plate having a width approximately the same as the horizontal length of the flat cassette and having a vertically long slit formed in the center in the width direction is provided. In a cassette holder of a dental panoramic X-ray imaging apparatus in which an X-ray film in the flat-plate cassette is irradiated with X-rays through a slit, between the X-ray shield plate and the accommodating portion of the flat-plate cassette. , A pair of left and right movable X-ray shields, each having a shape sufficient to cover the left and right halves of the flat cassette, are arranged symmetrically on the left and right sides of the X-ray shield, with the vertically long slit position sandwiched therebetween. In addition, the pair of movable X-ray shielding plates are selectively supported by the movable X-ray shielding plates as the flat cassettes are moved by the movable X-ray shielding plates. Is obtained is characterized in that is provided with a mechanism for moving to with its flat cassette so as to be covered.

[Action]

In the cassette holder having the first configuration, the left and right edges of the X-ray shield plate disposed on the side facing the X-ray source are X-rays.
Since it is protruding toward the radiation source, many secondary X-rays are generated from the subject's head when the primary X-rays emitted from the X-ray source penetrate the subject during X-ray imaging. Even if it scatters in a wide angle direction, the scattering X
X-rays are blocked by the protrusions on the left and right edges of the X-ray shield, and even when the width of the cassette holder is small and a part of the flat-shaped cassette projects largely from the side end face, the scattered X-rays are flat-shaped. It is prevented from entering the X-ray film surface inside.

Further, in the cassette holder according to the above-mentioned another configuration, a pair of left and right movable X-ray shield plates arranged between the X-ray shield plate and the accommodating portion of the flat-plate cassette as the flat-plate cassette moves. Either one of them moves together with the flat cassette, and the movable X-ray shield plate always covers either the left or right half surface of the flat cassette. Therefore, since the horizontal width of the cassette holder is almost the same as the horizontal length of the flat cassette, a part of the flat cassette protrudes from the side end surface of the cassette holder during X-ray photography, but Even if many secondary X-rays are generated from a certain subject's head and are scattered in a wide angle direction, the scattered X-rays are blocked by the movable X-ray shielding plate, and scattered X-rays are scattered. Is prevented from entering the X-ray film surface in the flat cassette.

〔Example〕

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

First, FIG. 2 is a perspective view of an essential part showing an example of the configuration of a dental panoramic X-ray imaging apparatus. This dental panoramic X-ray imaging apparatus is composed of a column 10 which is vertically held on the floor.
The arm drive unit 12 is supported so as to be able to move up and down on the column 10, and is horizontally hung from the column 10.
A horizontal arm 14 rotatably supported in a horizontal plane,
Positioning the X-ray tube device 16 suspended from one end of the horizontal arm 14, the cassette holder 18 suspended from the other end of the horizontal arm 14 facing the X-ray tube device 16, and the head and jaw of the subject. It is composed of a head and jaw fixing device 20 and the like which are fixed. The cassette holder 18 is provided with an X-ray shield plate on the side facing the X-ray tube device 16, and a longitudinal slit 22 is formed at the center in the width direction. In the cassette holder 18, a flat plate-shaped cassette 24 containing an X-ray film therein is housed in a vertical posture.
The 24 is adapted to move linearly in one direction in accordance with the rotational movement of the horizontal arm 14. Also, the cassette holder 18
The horizontal width of is set to be substantially the same as the horizontal length of the flat cassette 24.

FIG. 1 shows an enlarged perspective view of the cassette holder 18. This cassette holder 18 is used for accommodating a housing 28 for a flat cassette 24.
A housing 26 in which is formed, a cassette carrier 30 that holds the flat cassette 24, and a reversibly rotatable drive motor 32 that linearly reciprocates the cassette carrier 30 that holds the flat cassette 24. . The lateral width of the housing 26 is substantially the same as or slightly shorter than the horizontal length (for example, 33 cm) of the flat-plate cassette 24. Then, on the front surface of the housing 26, that is, on the surface facing the X-ray tube device 16 (see FIG. 2), in the central portion thereof,
A central shielding plate 34 for shielding X-rays, which is formed of, for example, a thin strip of lead in the form of a strip, is arranged, the front surface is formed into an arc surface on both left and right sides thereof, and each outer side is an X-ray tube device. A pair of projecting members 36, 36 protruding in the direction of 16 are symmetrically projected, and left and right shielding plates 38, 38 for shielding X-rays formed by a thin plate of lead are formed on each front surface forming an arc surface thereof. It is arranged. The central shielding plate 34 and the left / right shielding plates 38, 38 constitute an X-ray shielding plate, and a vertically long slit 22 is formed in the center of the central shielding plate 34 to allow passage of X-rays. Incidentally, the protrusion 36,
36 may be formed into a solid structure by casting aluminum, for example, or may be formed into a hollow structure made of a metal plate frame. In addition, the distance from the front surface of the flat plate-shaped cassette 24 to the outer end sides of the protrusions 36, 36 is set such that when the flat plate-shaped cassette 24 protrudes most from the side end face of the cassette holder 18,
That is, at the start and end of the panoramic X-ray photography, it is possible to effectively prevent secondary X-rays scattered from the subject's head, which is the subject, from entering the side edges of the X-ray film in the flat cassette 24. It is set as much as possible, but for example 60
It is set to about 65 mm. Further, the position of the flat cassette 24 shown in FIG. 1 is at the time of starting the panoramic X-ray imaging, and the flat cassette 24 is shown in accordance with the orbiting movement of the X-ray tube device 16 and the cassette holder 18. The linear movement is performed at a variable speed from the above position in the direction of the arrow a, and the photographing ends when the right end portion reaches the position of the vertically long slit 22 of the central shielding plate 34.

The cassette holder 40 shown in FIG. 3 has protrusions 42, 42 whose front surface has an arcuate surface, on the front surface of which a plate-like member, for example, an X-ray shielding plate 44 made of a thin plate of a ship, is arranged. This is an example in which a vertically long slit 46 for passing X-rays is formed in the center in the width direction. In this cassette holder 40,
The entire housing can be made of an X-ray transparent material such as an aluminum plate and a brass plate. As in the cassette holder 18 shown in FIG. 1, the center of the front surface of the housing 26 is made of an X-ray shielding material. The shield plate 34 may or may not be provided.

In the cassette holder 50 shown in FIG. 4, the front faces of the protrusions 52, 52 are formed in a flat shape, and the left and right shield plates 54, 54 in a flat plate shape are arranged on the front faces of the pair of protrusions 52, 52. This is an example of setting.
Further, the cassette holder 60 shown in FIG. 5 is an example in which the left and right shield plates 64, 64 having a hook-shaped cross section are arranged directly on the front surface of the housing without providing a protruding body. The fourth
The cassette holders 50 and 60 shown in FIGS.
Similar to the cassette holder 18 shown in the figure, the X-ray shield is
Central shields 56 and 66 with longitudinal slits 58 and 68 and left
It is composed of right shield plates 54, 54; 64, 64.

Next, the operation of the cassette holder 18 according to the embodiment shown in FIG. 1 will be described based on FIG. 6 showing a schematic plan view.

In the figure, the position and state of S indicated by the solid line represent the start time point of panoramic X-ray imaging, the position and state of M indicated by the two-dot chain line during the front tooth part imaging, and the position and state of F similarly the end point of imaging. Respectively. At the start of shooting, the X-ray shield 70 consisting of the center shield and the left and right shields
At the position of the vertical slit 22 of the flat cassette 24 (hence,
The left end portion of the X-ray film stored therein is arranged, while the flat plate-shaped cassette 24 projects substantially rightward from the right end surface of the cassette holder 18 to the right outside thereof. When an X-ray beam is radiated from the X-ray tube 72 of the X-ray tube device in this state, the radiated X-ray R passes through the subject's head 74, and the transmitted X-ray T becomes the X-ray shield plate. 70 vertical slits 22
The light passes through the plane and enters the left end of the flat cassette 24. In this case, when the emitted X-rays R pass through the head 74 of the subject, the secondary X-rays are scattered from the head 74 of the subject. This scattering X
The line D is radiated over a wide angle range, but in the cassette holder 18, the end side of the X-ray shield plate 70 protrudes toward the X-ray tube 72, and therefore, in FIG. The angle θ from the center O of the examiner's head 74 to the transmitted X-ray T
The scattered X-ray D scattered in the direction within the range of
Will be blocked by. Therefore, the flat cassette
Even if the right half surface of 24 projects from the right end surface of the cassette holder 18, the projecting portion is scattered by the X-ray shielding plate 70.
X-ray film is scattered X
Sensitivity to line D is prevented.

Then, as the X-ray tube 72 and the cassette holder 18 rotate in the direction of the arrow b, the flat cassette 24 moves linearly in the direction of the arrow a while photographing proceeds. After the front tooth portion is photographed at the position M and the state, Shooting ends at the position and state of F. At the end of this photographing, the right end of the flat cassette 24 is located at the position of the vertically long slit 22 of the X-ray shield 70, so that the flat cassette 24 moves outward from the left end surface of the cassette holder 18. The left half will stick out. Even in this case, it occurs in the head 74 of the subject,
The scattered X-ray D'scattered from the center O in the direction within the range of the angle .theta. 'With respect to the transmitted X-ray T'is blocked by the X-ray shielding plate 70 whose edge is protruded, and the left half surface of the flat cassette 24. Are protected from scattered X-rays D '.

FIG. 7 is a schematic plan view showing another configuration example of the cassette holder of the present invention. In the figure, illustration of the housing and the like is omitted, and only the X-ray shield plate and the flat plate-shaped cassette of the cassette holder are shown, and their operation processes are shown in order. This cassette holder has a horizontal width of about the same size as the horizontal length of the flat cassette 80, and in addition to the flat X-ray shield plate 82 in which a vertically long slit 84 is formed in the center in the width direction, A pair of left and right movable X-ray shield plates between the X-ray shield plate 82 and the accommodating portion of the flat cassette 80.
It has 86 and 88. The movable X-ray shields 86 and 88 have a shape sufficient to cover the left and right halves of the flat cassette 80, respectively, and the movable X-ray shields 86 and 88 are located on the left and right sides of the vertical slit 84 of the X-ray shield 82. They are arranged symmetrically. Then, the left movable X-ray shielding plate 86 moves to the left, and the right movable X-ray shielding plate 88.
Are linearly movable in the right direction.

FIG. 7 (A) shows a state at the time of starting the panoramic X-ray imaging. Prior to this state, the flat plate-shaped cassette 80 is once placed behind the X-ray shielding plate 82 at a position overlapping with it (FIG. 7A). (See (B)), at that position, for example, electromagnetic clutches 92, 92 provided on a cassette carrier (not shown) for holding and moving the flat plate-shaped cassette 80 integrally are operated so that the cassette carrier can be moved to the right side. Movable X
By attracting the line shield 88, the flat cassette 80
The right movable X-ray shield plate 88 and the right movable X-ray shield plate 88 can be moved together. After that, the flat plate cassette 80 and the right movable X-ray shield plate 88 are integrally moved to the right by the cassette carrier, and the left end portion of the flat plate cassette 80 is X-rayed as shown in FIG. It is aligned with the position of the vertically long slit 84 of the shielding plate 82. At this time, the left movable X-ray shield plate 86 remains behind the left half surface of the X-ray shield plate 82 because the electromagnetic clutches 90, 90 are released. Although the imaging is started in the state shown in this figure (A), the right half surface of the flat cassette 80 protruding from the right end surface of the cassette holder is protected from the scattered X-rays by the right movable X-ray shield plate 88. Fully protected. Then, when the photographing progresses to reach the state of the front tooth photographing, the electromagnetic clutches 92, 92 are released, and at the same time, the electromagnetic clutch 90, as shown in FIG.
When 90 is activated and the left movable X-ray shielding plate 86 is attracted to the cassette carrier, the flat cassette 80 and the left movable X-ray shielding plate 86 can be moved together. Subsequently, the flat-plate cassette 80 and the left movable X-ray shield plate 86 are integrally moved to the left by the cassette carrier,
Eventually, as shown in FIG. 7C, the right end of the flat cassette 80 comes to the position of the vertically long slit 84 of the X-ray shielding plate 82, and the photographing ends. At the end of this photographing, the left half surface of the flat cassette 80 projects from the left end surface of the cassette holder, but the left half surface is completely protected from the scattered X-rays by the left movable X-ray shield plate 86, No scattered X-rays will be taken.

The cassette holder according to the present invention has the above-mentioned configuration, but the scope of the present invention is not limited by the above description and the contents of the drawings, and various modifications are possible without departing from the scope of the invention. May be included. For example, the lateral width of the X-ray shielding plate does not necessarily have to be formed to have the same dimension as the lateral width of the housing of the cassette holder, and the moving direction of the flat cassette may be opposite to that in the above-described embodiment. Furthermore, the protrusion distance of the X-ray shielding plate is
It may be larger than 60-65 mm or smaller.

[Effect of device]

Since the present invention is constructed and operates as described above, when the cassette holder according to the present invention is provided in the dental panoramic X-ray imaging apparatus of the type using the flat-plate-shaped cassette, the cassette holder does not have to be upsized. , It is possible to effectively prevent scattered X-rays generated during X-ray imaging from entering the X-ray film surface in the flat cassette, and to improve the contrast, sharpness, and resolution of the image captured on the film surface. Can be improved.

Further, in the cassette holder of the sixth aspect, the housing of the cassette holder can be easily manufactured, and the manufacturing cost can be slightly reduced.

Further, in the cassette holder of the seventh aspect, the entire front surface of the flat-plate-shaped cassette is always covered with the X-ray shielding plate, so that the protection from scattered X-rays during X-ray imaging becomes more complete.

[Brief description of drawings]

FIG. 1 shows a dental panorama X according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view of a cassette holder of a radiographic apparatus, FIG. 2 is a perspective view of an essential part showing an example of the configuration of a dental panoramic X-ray apparatus, and FIGS. 6 is a perspective view of a main part of the cassette holder according to the embodiment.
FIG. 7 is a schematic plan view for explaining the operation of the cassette holder shown in FIG. 1, and FIG. 7 is a schematic plan view showing another configuration example of the cassette holder of the present invention. 10 …… Support pillar, 12 …… Arm drive part, 14 …… Horizontal arm,
16 ... X-ray tube device, 18, 40, 50, 60 ... Cassette holder, 22, 58, 68 ... Vertical slit, 24, 80 ... Flat cassette, 30 ... Cassette carrier, 34, 56, 66 ...... Center shield, 36, 42, 52 ...... Projection body, 38, 54, 64 ...... Left / right shield, 44 ...... X-ray shield, 46 ...... Vertical slit, 82 ...
… Flat X-ray shield, 84… Vertical slits, 86, 88…
… Movable X-ray shield, 90, 92… Electromagnetic clutch.

Claims (7)

[Scope of utility model registration request] Claim: What is claimed is: 1. An X-ray source, which is hung from an arm drive section horizontally extending from a support and rotatably supported in a horizontal plane, at one end of the horizontal arm and at the other end of the horizontal arm. The plate-shaped cassette is hung down facing the X
It is housed in a vertical posture facing the radiation source, and the flat-plate cassette is held so as to move linearly in one direction in accordance with the rotational movement of the horizontal arm, and is disposed on the side facing the X-ray source. In the cassette holder of the dental panoramic X-ray imaging apparatus, the X-ray film in the flat plate-shaped cassette is irradiated with X-rays through the longitudinal slit formed in the center in the width direction of the X-ray shielding plate. A cassette holder for a dental panoramic X-ray imaging apparatus, wherein at least both left and right sides of an X-ray shield plate are projected toward the X-ray source. 2. The cassette holder for a dental panoramic X-ray imaging apparatus according to claim 1, wherein the X-ray shielding plate has an arc surface. 3. A cassette holder for a dental panoramic X-ray imaging apparatus according to claim 1, wherein the X-ray shielding plate has a flat surface. 4. The cassette holder for a dental panoramic X-ray imaging apparatus according to claim 1, wherein the X-ray shield has a hook-shaped cross section. 5. An X-ray shielding plate comprises a strip-shaped central shielding plate having longitudinal slits for passing X-rays, and a pair of left and right shielding plates symmetrically arranged on the left and right sides thereof. A cassette holder for a dental panoramic X-ray imaging apparatus according to claim 1. 6. The X-ray shielding plate is made of one plate-shaped body, and a longitudinal slit for passing X-rays is formed in the center of the plate-shaped body in the width direction. A cassette holder for the dental panoramic X-ray imaging apparatus described in. 7. An X-ray source hung at an end of a horizontal arm that is suspended from an arm drive portion that horizontally extends from a column and rotatably supported in a horizontal plane, and the other end of the horizontal arm. The plate-shaped cassette is hung down facing the X
While accommodating in a vertical posture facing the radiation source, the flat plate-shaped cassette is held so as to be linearly moved in one direction in accordance with the rotational movement of the horizontal arm, and the flat cassette is held on the side facing the X-ray source. An X-ray shield plate having a width approximately the same as the length of the flat cassette in the left-right direction and having a vertically long slit formed in the center in the width direction is provided.
In the cassette holder of the dental panoramic X-ray imaging apparatus, the X-ray film in the flat cassette is irradiated with X-rays through the longitudinal slits of the line shield.
Between the X-ray shielding plate and the accommodating portion of the flat cassette, a pair of left and right movable X-ray shielding plates each having a shape sufficient to cover each of the left and right halves of the flat cassette are provided.
The vertically elongated slits of the line shield plate are arranged symmetrically on the left and right sides of the line shield plate, and are supported movably in opposite left and right directions, and the pair of movable X-ray shield plates are moved along with the movement of the flat cassette. Alternatively, a cassette for a dental panoramic X-ray imaging apparatus characterized in that a movable X-ray shielding plate covers a half surface of the flat-plate cassette so as to move the flat-cassette together with the flat-plate cassette. holder.