JP5436305B2 - Radiography apparatus and compression plate - Google Patents

Description

  The present invention relates to a medical radiation imaging apparatus and a compression plate used in the medical radiation imaging apparatus.

  2. Description of the Related Art There is a breast radiography apparatus (mammography) that takes radiographic images of a subject's breast for the purpose of early detection of breast cancer. In this type of radiation imaging apparatus, a breast placed on the imaging surface of an imaging table is compressed with a compression plate, and a radiation image of the breast is captured in this compressed state (see, for example, Patent Document 1).

US Pat. No. 5,398,272

  By the way, since the radiation image of the breast is taken in a state where the breast is compressed by the compression plate, the compression plate is required to be easy to transmit the radiation. For this reason, the compression plate is often designed so that the thickness of the part through which the radiation is transmitted is thin so that the radiation is easily transmitted.

  On the other hand, in order to suppress the exposure dose of the subject, a radiographic image of the breast is taken in a state where the breast is expanded so that the thickness of the breast (hereinafter referred to as breast thickness) is reduced to some extent.

  In Patent Document 1, a breast is pressed with a flat bottom plate of a box-shaped compression plate. However, depending on the thickness of the bottom plate, a part of the bottom plate (near the center) may rise to the inside of the box due to a reaction force from the breast during breast compression. When the bottom plate is raised, the breast thickness of the raised part becomes thicker than the thickness of the other parts, so the density difference in the radiographic image of the breast becomes large, making it difficult to diagnose the radiographic image and making the diagnostic descend.

  The present invention has been made in consideration of the above facts, and has an object to reduce the density difference of the radiation image of the breast and improve the diagnostic performance.

The invention of claim 1 is a radiographic apparatus for imaging a radiographic image of a breast of a subject, and can be brought into and out of contact with an imaging table having a planar imaging surface against which the breast is pressed. The center side of the apparatus longitudinal direction and the apparatus left-right direction from the outer peripheral edge portion where the breast is pressed against the imaging surface and the plate thickness is constant and a reinforcing plate is formed so as to surround the surface opposite to the imaging surface. A convex plate that is continuously formed and protrudes toward the imaging surface side, and has a flexible compression plate that is flexed by a reaction force from the breast during breast compression , and the convex shape of the compression plate is in the thickness direction It is a radiography apparatus which is made into the shape curved continuously toward the top part from the said outer peripheral edge part in all the cross sections .

In the invention of claim 1, since the compression plate has a convex shape in which the center side in the apparatus front-rear direction and the apparatus left-right direction protrudes from the outer peripheral edge to the imaging surface side, it receives the reaction force from the breast during breast compression. The pressed plate bends in the opposite direction to the imaging surface side and approaches a flat plate shape.
Since the compression plate approaches a flat plate shape when breast is compressed in this way, for example, compared to a plate-like compression plate portion that bulges to the opposite side to the imaging surface side during breast compression, The thickness can be made uniform. Thereby, the density difference of the radiographic image of the breast becomes small, and the diagnostic property of the radiographic image improves.

  A second aspect of the present invention is the radiographic apparatus according to the first aspect, wherein the top portion of the compression plate is positioned closer to the base of the breast than the central portion of the compression plate.

  In the invention of claim 2, since the thickness of the breast is usually thicker on the base side than on the tip side (nipple side), the breast is compressed toward the base of the breast where the reaction force from the breast becomes strong. The top of the plate is located. Thereby, the breast thickness at the time of compression can be made more uniform.

A third aspect of the present invention is the radiation imaging apparatus according to the first or second aspect , wherein the convex amount of the compression plate satisfies 1 to 3 mm.

In the invention of claim 3 , the convex amount of the compression plate satisfies 1 to 3 mm. When the convex amount of the compression plate is less than 1 mm, the compression plate easily rises to the opposite side to the imaging surface side due to the reaction force from the breast during breast compression, and the effect of making the breast thickness close to uniform during compression is reduced. In addition, when the convex amount of the compression plate exceeds 3 mm, the portion of the breast compressed by the top of the compression plate is pushed more than necessary, and the burden on the subject (discomfort, pain, etc.) at the time of breast compression may increase. There is.
Therefore, the convex amount of the compression plate preferably satisfies 1 to 3 mm.

According to a fourth aspect of the present invention, there is provided a compression plate for use in a radiographic apparatus for capturing a radiographic image by pressing a subject's breast against a planar imaging surface of an imaging table, the plate thickness being constant and the radiographic apparatus being used. The center of the apparatus longitudinal direction and the apparatus left-right direction from the outer peripheral edge portion where the reinforcing plate is formed so as to be surrounded by the surface opposite to the imaging surface when used and made separable from the imaging surface The side is a convex shape that is continuously formed and protruded toward the imaging surface side as one side in the plate thickness direction , and the convex shape is continuous from the outer peripheral edge to the top in all cross sections in the plate thickness direction. It is a compression plate which has a flexible shape and is bent by a reaction force from the breast when the breast is compressed.

In the invention of claim 4 , since the compression plate has a convex shape with the central side protruding from the outer peripheral edge to one side in the plate thickness direction, for example, one side in the plate thickness direction is the photographing surface side. When mounted on a radiation imaging apparatus and the breast is compressed with a compression plate, the compression plate is bent in the opposite direction with respect to the imaging surface and receives a reaction force from the breast and approaches a flat plate shape.
Since the compression plate approaches a flat plate shape at the time of breast compression in this way, the thickness of the breast at the time of compression is compared with, for example, a flat plate compression plate that is bent and swells to the opposite side to the imaging surface side at the time of breast compression. Can be made uniform. Thereby, the density difference of the radiographic image of the breast is reduced, and the diagnostic property of the radiographic image is improved.

  As described above, according to the present invention, it is possible to reduce the density difference of the radiation image of the breast and improve the diagnostic performance.

1 is a perspective view of a radiation imaging apparatus according to a first embodiment of the present invention. It is a perspective view of the radiography apparatus which shows the state which made the compression board of the radiography apparatus of 1st Embodiment approach the imaging surface. It is the top view which looked at the compression board of the radiography apparatus of 1st Embodiment from upper direction. (A) It is a top view of the compression board of 1st Embodiment. (B) It is the BB line end view of Drawing 4 (A). (C) It is the CC sectional view taken on the line of FIG. It is a sectional side view of a compression board and an imaging stand which shows the state which mounted the breast on the imaging surface of 1st Embodiment. It is a sectional side view of a compression board and an imaging stand which shows the state which is compressing the breast on the imaging surface of 1st Embodiment with a compression board. It is sectional drawing which looked at the compression board and imaging | photography stand from the front side which shows the state which is pressing the breast on the imaging surface of 1st Embodiment with a compression board. (A) It is a top view of the 1st modification of the compression board of 1st Embodiment. (B) It is a BB line end view of Drawing 8 (A). (C) It is the CC sectional view taken on the line of FIG. 8 (A). (A) It is a top view of the 2nd modification of the compression board of 1st Embodiment. (B) It is the BB line end elevation of Drawing 9 (A). (C) It is the CC sectional view taken on the line of FIG.

  Hereinafter, embodiments of the radiation imaging apparatus and the compression plate of the present invention will be described with reference to the drawings.

[First embodiment]
(overall structure)
1 and 2 are perspective views of an X-ray imaging apparatus (so-called mammography) 10 that is a first embodiment of a radiation imaging apparatus. The X-ray imaging apparatus 10 is an apparatus that captures an X-ray image of a breast N of a standing subject W (see FIGS. 3 and 5). CC (head-to-tail direction (Cranio & Caudal)) imaging and MLO (inside and outside) It is an apparatus that can perform both oblique-direction (Medium-Lateral-Oblique) imaging. The arrow X direction in the figure indicates the front-rear direction of the X-ray imaging apparatus 10 (apparatus front side-apparatus rear side direction), and the arrow Y direction indicates the left-right direction of the X-ray imaging apparatus 10 (apparatus left side-apparatus right direction). Is shown.

  The X-ray imaging apparatus 10 includes a substantially U-shaped measurement unit 12 provided on the front side of the apparatus, and a base unit 14 that supports the measurement unit 12 from behind. The measurement unit 12 is provided with a rotation shaft 16 that extends to the back side of the apparatus and is rotatably supported by the base unit 14. The measurement is performed by the rotation shaft 16 being supported by the base unit 14. The part 12 is rotatably supported by the base part 14.

  The measurement unit 12 includes an imaging table 22 having a planar imaging surface 20 on which a breast N (see FIGS. 3 and 5 to 7) of a standing subject W (patient) is pressed, and an X-ray tube (not shown). ) And a radiation irradiation device 24 as an X-ray source that irradiates the imaging surface 20 with X-rays for examination, and compression that can be brought into and out of contact with the imaging surface 20 and presses the breast N against the imaging surface 20 A plate 40, an imaging table 22, and a holding unit 28 that holds the radiation irradiation device 24 are provided.

  The holding unit 28 holds the imaging table 22 and the radiation irradiation device 24 so that the imaging surface 20 and the radiation irradiation device 24 are separated from each other by a predetermined interval. The holding unit 28 is provided with a slide holding unit 39 that can slide between the imaging surface 20 and the radiation irradiation device 24. The slide holding portion 39 supports the compression plate 40 via a connecting portion 36 described later. With this configuration, the compression plate 40 can move in the contact / separation direction (see FIGS. 1 and 2) with respect to the imaging surface 20.

  Further, the holding unit 28 is provided with a pair of handles 34 that the subject W holds with both hands at the time of photographing so as to sandwich the photographing surface 20.

  A chest wall abutting portion 38 for abutting a chest portion below the breast N of the subject W (see FIG. 5) is provided on the apparatus front side of the imaging table 22 at the time of CC imaging. Further, an X-ray detector (not shown) as a radiation detector that is irradiated with radiation that has passed through the imaging surface 20 is provided inside the imaging table 22.

(Pressure plate)
As shown in FIGS. 4A to 4C, the compression plate 40 has a substantially constant plate thickness, and has a convex shape in which the center side protrudes to one side in the plate thickness direction from the outer peripheral edge. . The compression plate 40 has a substantially rectangular shape in plan view.

  A reinforcing plate 44 is erected on the outer peripheral edge of the compression plate 40. The reinforcing plate 44 extends to the other side in the thickness direction. The reinforcing plate 44 is disposed so as to surround the outer peripheral edge portion of the compression plate 40 in plan view.

Furthermore, the compression plate 40 is formed of a resin material having a property of easily transmitting radiation (X-rays in the present embodiment). Examples of the resin material include PC (polycarbonate), PET (polyethylene terephthalate), acrylic, and PP (polypropylene). However, the resin material is not necessarily limited to these resin materials. By forming the compression plate 40 from a resin material in this way, the compression plate 40 has flexibility.
In the present embodiment, the compression plate 40 and the reinforcing plate 44 are integrally formed.

As shown in FIGS. 1 and 2, the compression plate 40 is attached to the slide holding portion 39 via the connecting portion 36 in a direction facing the imaging surface 20. At this time, the compression plate 40 is attached so that one side (the protruding shape side) in the thickness direction of the compression plate 40 becomes the imaging surface 20 side.
The reinforcing plate 44 includes a reinforcing plate 44A on the front side of the apparatus (front side when viewed from the subject W), a reinforcing plate 44B on the back side of the apparatus (back side when viewed from the subject W), and a left side of the apparatus (left side when viewed from the subject W). ) And a reinforcing plate 44D on the right side of the apparatus (right side as viewed from the subject W).

  As shown in FIGS. 4A and 4B, the top portion 42 of the compression plate 40 is a central portion (center line CL <b> 1 in FIG. 4) of the X-ray imaging apparatus 10 in the front-rear direction (the arrow X direction in the drawing). It is located on the base side of the breast N. That is, the top portion 42 is closer to the reinforcing plate 44A side than the reinforcing plate 44B.

Specifically, as shown in FIG. 4B, the distance in the front-rear direction of the compression plate 40 is L, and the distance from the reinforcing plate 44A to the center portion in the front-rear direction of the compression plate 40 is L / 2. When the distance from the plate 44A to the top portion 42 is a, the relationship a ≦ L / 2 <L is satisfied.
As shown in FIG. 4C, the top portion 42 of the compression plate 40 is located in the center portion (the center line CL2 in FIG. 4) in the left-right direction (the arrow Y direction in the drawing) of the X-ray imaging apparatus 10. doing. That is, the top part 42 is located in the central part between the reinforcing plate 44C and the reinforcing plate 44D.

  Further, as shown in FIGS. 4B and 4C, the distance from the outer peripheral edge portion of the compression plate 40 to the top portion 42, that is, the convex amount H is set to 1 to 3 mm.

The convex shape of the compression plate 40 is a shape that is continuously curved from the outer peripheral edge portion to the top portion 42 (convex vertex) in all cross sections in the thickness direction, in other words, the surface of the compression plate 40 is a substantially rotating object. The shape is a surface.
In FIG. 4A, the convex shape of the compression plate 40 is shown using contour lines (dashed lines).

Next, the operation of the X-ray imaging apparatus 10 and the compression plate 40 of the first embodiment will be described.
First, when CC imaging is performed using the X-ray imaging apparatus 10, the breast N of the subject W is placed on the imaging surface 20 of the imaging table 22 as shown in FIGS. 3 and 5. After the breast N is placed at a predetermined position, the slide holder 39 is slid toward the imaging table 22 so that the compression plate 40 approaches the imaging surface 20. Then, the breast N is pressed against the imaging surface 20 by the approaching compression plate 40, and is expanded until it becomes thick enough to obtain a clear radiation image even when the radiation output is lowered in order to suppress the exposure dose of the subject W. . Thereafter, radiation is emitted from the radiation irradiating device 24 while the breast N is compressed, and the radiation amount transmitted through the breast N is detected by a radiation detector (not shown) of the imaging table 22 to form a radiation image.

  Here, since the compression plate 40 has a convex shape with the center side protruding from the outer peripheral edge toward the imaging surface 20, the reaction force from the breast N is applied during breast compression, as shown in FIGS. The received compression plate 40 bends in the opposite direction with respect to the imaging surface 20 side and approaches a flat plate shape. Thus, since the compression plate 40 approaches a flat plate shape at the time of breast compression (that is, the compression surface approaches a flat shape), for example, the flat plate compression plate is opposite to the imaging surface 20 side at the time of breast compression. The thickness of the breast N at the time of compression can be made closer to the uniform as compared with the bent and raised one. Thereby, the density difference of the radiation image of the breast N becomes small, and the diagnostic property of the said radiation image improves.

  Further, since the thickness of the compression plate 40 is constant, the amount of transmitted radiation is uniform, and the image quality of the radiation image of the breast N is improved.

  Further, since the thickness of the breast N is thicker on the base side than the tip side (nipple side), the convex shape of the compression plate 40 on the breast base side where the reaction force from the breast N becomes strong at the time of breast compression. The top 42 is located. Thereby, the thickness of the breast N at the time of compression can be made more uniform.

  Since the reinforcing plate 44 is erected on the outer peripheral edge of the compression plate 40 on the side opposite to the imaging surface 20 side, the rigidity of the compression plate 40 is improved. This makes it possible to sufficiently spread the breast N during breast compression.

  Further, the convex amount H of the compression plate 40 satisfies 1 to 3 mm. When the convex amount H of the compression plate 40 is less than 1 mm, the compression plate 40 tends to rise to the opposite side with respect to the imaging surface 20 due to the reaction force from the breast N during breast compression, and the thickness of the breast N during compression is uniform. The effect of approaching is reduced. When the convex amount H of the compression plate 40 exceeds 3 mm, the part of the breast N that is compressed by the top 42 of the compression plate 40 is pushed more than necessary, and the burden on the subject W at the time of breast compression (discomfort, pain, etc.) May increase.

  In the above-described embodiment, as shown in FIG. 4C, the top portion 42 of the compression plate 40 is configured to be positioned at the central portion in the left-right direction of the X-ray imaging apparatus 10 (center line CL2 in the drawing). The present invention is not limited to this configuration, and the top portion 42 of the compression plate 40 may be located on the left side or the right side of the central portion (the center line CL2 in the drawing) of the X-ray imaging apparatus 10 in the left-right direction. 8A to 8C, in the first modified example, the top portion 52 of the compression plate 50 is located on the left side of the center portion (center line CL2) in the left-right direction of the X-ray imaging apparatus 10. The configuration is shown.

  In the above-described embodiment, as shown in FIGS. 4B and 8B, the convex shape of the compression plates 40, 50 is from the outer peripheral edge to the tops 42, 52A in all cross sections in the plate thickness direction. However, the present invention is not limited to this configuration, and the thickness of the compression plate 60 of the second modification shown in FIGS. It is good also as a structure which curves, having the inflection point 63 toward the top part 62 from an outer peripheral edge part in all the cross sections of a direction.

  Furthermore, in the above-described embodiment, the compression plates 40, 50, 60 are configured to have a substantially rectangular shape in plan view. However, the present invention is not limited to this configuration, and is generally circular or semicircular in plan view. Any shape such as a substantially trapezoidal shape may be used.

  And in the above-mentioned embodiment, although it has set as the structure which stands up the reinforcement board 44 in the outer peripheral edge part of the compression boards 40, 50, 60, this invention is not limited to this structure, and does not stand up the reinforcement board 44 May be.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

10 X-ray imaging equipment (radiography equipment)
40 compression plate 42 top 44 reinforcing plate 50 compression plate 52 top 60 compression plate 62 top CL1 center line CL2 center line H convex amount N breast W test subject

Claims (4)

A radiographic apparatus for taking a radiographic image of a breast of a subject,
An imaging table having a planar imaging surface against which the breast is pressed;
An outer peripheral edge portion which can be brought into contact with and separated from the imaging surface, presses the breast against the imaging surface, has a constant plate thickness , and is formed with a reinforcing plate so as to surround a surface opposite to the imaging surface From the front and rear direction of the device and the central side of the left and right direction of the device is a convex shape that is continuously formed and protrudes toward the imaging surface side, and has a flexible compression plate that is bent by a reaction force from the breast at the time of breast compression,
With
The convex shape of the compression plate is a radiation imaging apparatus in which all the cross sections in the plate thickness direction are continuously curved from the outer peripheral edge toward the top .   The radiographic apparatus according to claim 1, wherein a top portion of the compression plate is located closer to a base of the breast than a central portion of the compression plate. The radiation imaging apparatus according to claim 1, wherein a convex amount of the compression plate satisfies 1 to 3 mm. A compression plate used in a radiographic apparatus that captures a radiographic image by pressing a subject's breast against a planar imaging surface of an imaging table,
An outer peripheral edge in which a reinforcing plate is formed so as to surround a surface opposite to the imaging surface when the plate thickness is constant and is used in the radiographic apparatus and can be brought into and out of contact with the imaging surface the center side of the front and rear devices from parts directions and apparatus left-right direction is to the to the imaging surface side is continuously formed protruding convex shape as one side in the thickness direction, and in all cross the convex shape in the thickness direction A compression plate that has a shape that is continuously curved from the outer peripheral edge toward the top, and is flexible due to a reaction force from the breast during breast compression .

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