JP2010046356A - Tomography breast imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tomography breast imaging system capable of more easily obtaining a tomography breast image by preventing the irregularity of an X-ray transmitting distance in a mammo CT. <P>SOLUTION: The tomography breast imaging system is equipped with: a top plate 12 equipped with a hole 14 permitting the breast B to pass; a breast housing member 15 which receives the breast B suspended from the hole 14, draws the breast B under negative pressure to draw the same from the ribs R and attracts the breast B to its inner wall to bring the same close to a columnar shape; an X-ray generator 20 for radiating a cone beam C; an X-ray detector 18 for detecting the incident intensity of X-rays; a stand 16 loaded with the X-ray generator 20 and the X-ray detector 18 to be rotated around a rotation axis A; and a control unit for controlling the motion of the top plate 12 and the stand 16 and the operation of the X-ray generator 20 and the X-ray detector 18. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a breast tomographic imaging apparatus using computer tomography (CT), and more particularly to a breast tomographic imaging apparatus including a breast support device applied to CT used for breast cancer diagnosis.

  Traditionally, breast cancer testing has been performed using palpation and ultrasound. However, these tests can be found only with cancer cells that have grown to some extent. For this reason, mammography using an X-ray transmission image, which is relatively easy to find calcification occurring in early breast cancer, has come to be used in combination. However, since mammography requires uniform breast thickness in order to obtain good image quality, the breast is sandwiched and flattened with a compression plate to obtain an X-ray transmission image, which may cause pain to the subject. is there. In addition, since the obtained image is a simple X-ray transmission image, it is difficult to determine the lesion when the target tumor part or calcification overlaps an object that forms an X-ray image such as a mammary gland.

  Therefore, a breast tomographic imaging apparatus (mammo CT) using computer tomography (CT) capable of obtaining a 3D image without compressing the breast has been developed. With mammo CT, small calcification can be detected without causing pain to the subject. Moreover, it can be accurately evaluated even when the X-ray opaque parts overlap, and is effective for early detection of breast cancer.

Patent Document 1 discloses an example of mammo CT.
The mammo CT disclosed in Patent Document 1 controls a bed having a hole in the breast position, a gantry that rotates horizontally around the hole, a motor that moves the bed and the gantry, and a switch that operates a measurement device. Device. The measurement apparatus includes an X-ray generation apparatus, an X-ray detection apparatus disposed opposite to the X-ray generation apparatus, and an arithmetic unit that reconstructs a tomographic image from an X-ray transmission image obtained by the X-ray detection apparatus. The X-ray generation device and the X-ray detection device are mounted on a gantry and acquire an X-ray transmission image of the breast from each direction while rotating around the breast together.

  The X-ray generator emits X-rays according to the drive switch. The X-ray becomes a cone-shaped cone beam, passes through the subject, and enters the X-ray detection apparatus. The X-ray detection apparatus is a flat panel detector (FPD) in which X-ray detection elements are arranged in a matrix on a plane. Each X-ray detection element accumulates the X-ray projected from the X-ray generator as a measurement signal corresponding to the remaining X-ray intensity absorbed by the substance in the optical path, and the FPD forms an X-ray transmission image at that time Will do. The X-ray detection apparatus can transmit an X-ray transmission image by scanning the measurement signal of each detection element and sequentially outputting it.

  When the subject lies on his / her bed and puts the breast to be measured into the hole, the breast hangs down between the X-ray generator and the X-ray detector. The subject presses the chest against the hole so that the breast is exposed to the measurement area as close to the chest wall. At the position where the breast hangs down, a breast container that draws the breast sufficiently from the chest wall and conforms to the shape of the inner wall to make it close to a cylindrical shape is placed, improving the reproducibility of the measurement. The breast container is formed in a cylindrical shape with a material that easily transmits X-rays. It is preferable to provide a cushion for relieving pain of the subject inside.

  The cone beam X-ray generator and FPD operate the X-ray generator for each predetermined angle while rotating around the breast container in which the subject breast fits, and take an X-ray transmission image with the X-ray detector. The image signal is transmitted to the reconstruction calculation device. The reconstruction calculation device reconstructs an X-ray transmission image into 3D, and creates an X-ray tomographic image of the breast. For example, 300 X-ray transmission images are taken and used per rotation.

In the X-ray tomographic image thus obtained, the calcified portion has an image generating power equivalent to that of bone, so that relatively small calcification can be easily visualized and early breast cancer can be found with a high probability. In addition, since the image is a three-dimensional image, it is possible to reliably detect a lesion part on the back side of a tissue such as a mammary gland. Therefore, early diagnosis of breast cancer can be accurately performed by using mammo CT together. Since breast cancer occurs relatively frequently near the chest wall, it is important to examine the vicinity of the breast root.
US Pat. No. 6,480,565

  When a cone beam is irradiated to the breast housed in the breast container, the breast root portion is regulated by the inner wall of the cylinder and has a certain transmission distance, but the transmission distance becomes shorter and the intensity of the transmitted light becomes stronger as it approaches the tip of the breast. Therefore, the detection sensitivity of the tumor and calcification in the breast changes depending on the breast position. When a large breast is to be inspected, the distance between the subject and the X-ray generator is enlarged so as to be included in the imaging range, or the X-ray generator and the X-ray detector are moved while moving in the rotation axis direction. For example, the detection sensitivity may be reduced or a complicated mechanism may be required, for example, by adding the analyzed X-ray transmission image.

  Accordingly, an object of the present invention is to provide a breast tomographic imaging apparatus that can easily obtain a breast tomographic image by preventing unevenness in the X-ray transmission distance in mammography CT. Another object of the present invention is to provide a breast tomography apparatus that enables early detection of breast cancer even in the vicinity of the nipple by a simple mechanism.

  In order to solve the above problems, a breast tomography apparatus according to the present invention includes a top plate that has a hole through which a breast passes and in which a subject lies on his / her face down and hangs down the breast from the hole. A cylindrical breast container that draws a breast drooping from the chest wall by pulling it with negative pressure and pulls the breast to the inner wall to approach a cylindrical shape, an X-ray generator that emits an X-ray cone beam, An X-ray detector including a two-dimensional detector having a plurality of X-ray detection elements arranged on the surface for detecting the incident intensity of X-rays emitted from the X-ray generator, and the X-ray generator and the X-ray detector are opposed to each other. And a control unit that controls the movement of the top plate, the base, the X-ray generation device, and the operation of the X-ray detector.

  According to the breast tomography apparatus according to the present invention, a cylindrical breast container that accepts a breast that is placed under a hole and hangs down from the hole pulls the breast from the chest wall by pulling with negative pressure, and attracts the breast to the inner wall. Can be close to a cylindrical shape. Since the breast has a cylindrical shape, the measurement length is shortened, the spread of the cone beam can be suppressed, the spatial resolution of the X-ray detector is improved, and small breast cancer signs are not overlooked. Can do. In addition, since the measurement region is included from the vicinity of the breast wall to the nipple portion, the oversight of the lesion is reduced. Further, since the difference in the X-ray transmission distance between the breast root and the distal end is reduced, the correction calculation is simplified and the tomography calculation is facilitated.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual configuration diagram conceptually showing an image acquisition unit of a breast tomographic imaging apparatus according to an embodiment of the present invention, and FIG. 2 is a system block diagram for explaining the overall configuration of the breast tomographic imaging apparatus.

  As shown in FIG. 1, the breast tomography apparatus 200 according to the present embodiment includes a hole 14 through which a breast is passed, and a subject P can lie down on his / her face and suspend a breast B from the hole 14. A cylindrical breast container 15 that is disposed below the hole 14 and receives a breast B that hangs down from the hole 14, an X-ray generator 20 that emits a radial X-ray cone beam C, and the X-ray generator 20 An X-ray detector 18 having a flat panel display (FPD) in which a plurality of X-ray detection elements for detecting the incident intensity of X-rays emitted and transmitted through an object are arranged on the surface, an X-ray generator 20 and X-ray detection The rack 18 is mounted so that the container 18 faces the rotation axis A across the rotation axis A.

  The rotation axis A is disposed so as to pass through the breast container 15. The gantry 16 rotates around the rotation axis A. The breast container 15 applies the negative pressure supplied from the negative pressure controller 22 to pull out the breast B from the chest wall, and draws the breast B to the inner wall of the cylindrical surface using various means to form a columnar shape. Store.

The breast tomography apparatus 200 further includes a control device that controls the movement of the top 12 and the gantry 16 and the operation of the X-ray generator 20 and the X-ray detector 18. The breast tomographic imaging apparatus 200 includes an image processing device and an image display device.
Referring to FIG. 2, the breast tomographic imaging apparatus 200 includes an image generation unit 110, an image processing unit 120, an image storage unit 130, an image display unit 140, an imaging unit 160, a top plate unit 170, and a breast storage unit 180. The

  Specifically, the image generation unit 110 includes an X-ray generation unit 113 corresponding to the X-ray generation device 20 and an X-ray detection unit 115 corresponding to the X-ray detector 18. When the trigger signal is received from the imaging unit 111, The X-ray generation unit 113 emits the cone beam C, and the X-ray detection unit 115 detects the cone beam C transmitted through the subject, generates an image signal, and transmits the image signal to the image processing unit 120.

The image processing unit 120 includes an image processing unit 121, an image correction unit 123, an image reconstruction unit 125, a confirmation image generation unit 127, and an adjustment value calculation unit 129.
The image processing unit 121 generates an image signal of an X-ray transmission image detected by the X-ray detection unit 115 based on the detection signal input from the image generation unit 110. The generated image signal is transmitted to the image correction unit 123 and also transmitted to the image storage unit 130 and the image display unit 140, and can be referred to as acquired image information.

The image correcting unit 123 corrects the acquired original image signal by removing noise and reducing artifacts, and transmits the corrected image to the image reconstruction unit 125 and the confirmation image generating unit 127.
When the image signals from each direction acquired for the subject are collected, the image reconstruction unit 125 performs a reconstruction operation to generate an image signal for forming the CT screen of the subject, and the image storage unit 130 and the image display To the unit 140.

The confirmation image generation unit 127 generates a confirmation image used for adjustment of the apparatus 200 and sends it to the adjustment value calculation unit 129. An image that shows the positional relationship between the screen and the subject is generated and related to the adjustment values of the device, such as whether the alignment is correct, whether it has the correct resolution, and does not include extra noise. Confirm.
The adjustment value calculation unit 129 calculates an adjustment value necessary for eliminating the deviation from the expected value for the position of the screen frame, the signal intensity, and other environmental values, and the photographing unit control unit 161 and the top panel unit control unit. 171.
The adjustment value can also be designated directly by the operator via the adjustment value input means 151. The adjustment value input unit 151 includes a data input device using a keyboard, a touch panel, or a mouse.

The image storage unit 130 is provided with image storage means 131 formed by an image memory or the like, and can be easily read and used when image information is required.
The image display unit 140 is provided with an image display unit 141 and a confirmation image display unit 143. The image display unit 141 displays a cross-sectional image or a stereoscopic image of a breast for confirming whether a tumor, calcification, cancer tissue, or the like is present in the breast as an image used for breast cancer diagnosis. The confirmation image display unit 143 displays an image that can be used to monitor or adjust the abnormality or malfunction of the breast tomography apparatus 200. In particular, when the adjustment is performed by the operator, it is necessary to make an adjustment while observing the image displayed by the confirmation image display unit 143.

  The imaging unit 160 includes an imaging unit rotation unit 163 controlled by the imaging unit control unit 161, an imaging unit lifting / lowering unit 165, an X-ray detection unit translation unit 167, and an X-ray generation unit translation unit 169. The imaging unit 111 that has driven the image generation unit 110 supplies a trigger signal to the imaging unit control unit 161 every time an imaging procedure is performed, and X-rays are transmitted via the imaging unit rotation unit 163 and the imaging unit elevating unit 165. The rotation and height of the gantry 16 on which the generation means 113 and the X-ray detection means 115 are mounted are adjusted to the next determined position. Further, the detection sensitivity can be adjusted by adjusting the distance to the X-ray detection means 115 and the X-ray generation means 113 or the subject B, that is, the rotation axis A.

  The top plate portion 170 includes a top plate translation means 173 and a top plate lift means 175 controlled by the top plate control means 171. The position of the cone beam C irradiating the subject B can be easily adjusted by raising and lowering the gantry 16, but since it is in a relative relationship, the height can be adjusted by raising and lowering the top 12 as well. Is possible. Further, when making a diagnosis by switching the left and right breasts, it is necessary to realign the rotation axis A of the gantry 16 with the position of the breast. In particular, when the top plate 12 has two holes that are aligned with the left and right breasts, the other hole is translated to the position of the rotation axis A for alignment.

  The breast storage unit 180 includes a breast sucking unit 183 and a breast columnarizing unit 185 controlled by the breast storage unit control unit 181. FIG. 3 is a diagram illustrating a configuration example of the breast storage unit 180. The breast sucking means 183 is a negative pressure device connected to the inside of the breast container 15, and as shown in FIG. 3A, negative pressure is applied to the breast B hanging from the hole 14 of the top plate 12 into the breast container 15. The light is sucked with the light negative pressure V <b> 1 supplied from the controller 22, and the breast B is pulled out to the vicinity of the rib R and stored in the breast container 15. The subject P lies on the top 12 and presses the chest against the hole 14 to be used for the examination of the breast B from the root. By further sucking at a predetermined negative pressure V1, the portion closer to the chest wall is obtained. In addition, the breast B can be used for the examination stably regardless of the subject P. Although the negative pressure V1 is supplied into the breast container 15 in the drawing, the inside of the gantry 16 is sealed to supply the negative pressure V1, the bottom of the breast container 15 is released, and the negative pressure is applied to the breast B. The pressure V1 may be applied.

  After the extracted breast B is stored in the breast container 15, as shown in an example in FIG. 3B, the breast B is attracted to the inner wall of the cylinder by the breast columnarization means 185 so as to approximate the columnar shape. . The breast columnarizing means 185 is formed with a cavity 23 in the cylindrical shell, and a plurality of holes 25 connected to the cavity 23 are provided on the inner wall surface, and the cavity 23 is provided with the second negative pressure V2 of the negative pressure controller 22. It may be a negative pressure device connected to a negative pressure pipe for supplying the pressure. FIG. 4 is a diagram for explaining a mechanism for forming a cylindrical breast by a negative pressure device. As shown in FIG. 4A, when the breast B is stored in the breast container 15, when a negative pressure V2 slightly higher than the negative pressure V1 applied in the breast container 15 is applied to the cavity 23, As shown in FIG. 4 (b), the breast B is drawn toward the inner wall from the portion near the base by the negative pressure supplied from the hole 25, and comes into close contact with the cylindrical inner wall, as shown in FIG. 4 (c). In addition, a cylindrical shape is formed.

  In this way, the cylindrical breast container 15 that is disposed under the hole 14 and receives the breast B that hangs down from the hole 14 draws the breast B from the chest wall by pulling it with negative pressure, and attracts the breast B to the inner wall to form a cylindrical shape. Therefore, the difference in the X-ray transmission distance between the root and the tip of the breast B becomes small, the breast tissue (fat) becomes uniform, and the lesioned part that is an abnormal tissue is easily visible. Further, since the breast B has a cylindrical shape, the measurement length from the base to the tip is shortened, and the spread of the cone beam C can be suppressed, and the spatial resolution of the X-ray detector 18 is improved. In addition, the oversight of lesions in the nipple portion is reduced.

The breast container 15 may be attached to the top plate 12 or attached to the gantry 16. The breast container 15 is preferably formed of a synthetic resin having a high X-ray transmittance. In addition, it is preferable that a suitable cushioning material is lined on the part that comes into contact with the breast in consideration of the touch of the subject.
In addition, since the size of the breast container in which the size of the breast varies depending on the subject, the diameter of the container can be adjusted according to the size of the breast. For example, the diameter of the breast container may be adjusted by forming a cylindrical portion by winding a plastic plate-like structure and abutting the edges, and separating or overlapping the abutting portions as appropriate. Alternatively, containers of different sizes may be prepared and the containers may be replaced according to the size of the breast.

FIG. 5 is a drawing for explaining another example of the breast columnarizing means 185.
The means of FIG. 5 shapes the breast B into a cylindrical shape by pulling the tape 29 affixed to the breast B on the side wall. As shown in FIG. 5 (a), the tip of the tape 29 with adhesive at the tip is affixed to the surface 31 of the breast B, and the other end of the tape 29 is inserted into the slot 27 provided on the side wall of the breast container 15. Leave it through. Then, the breast B hanging in the breast container 15 is sucked with the negative pressure V1 and pulled to the vicinity of the rib R, and further, as shown in FIG. 5 (b), the tape 29 is kept while maintaining the negative pressure V1. By pulling and attracting the breast B to the inner wall of the cylinder, it can be shaped into a columnar shape. Note that the negative pressure V1 is applied to the breast B in the breast container 15 by sealing the inside of the gantry 16 using the breast container 15 with the bottom opened and supplying the negative pressure V1 of the negative pressure controller 22. You may do it.

FIG. 6 is a drawing for explaining still another example of the breast columnarizing means 185.
The means in FIG. 6 is to shape the breast B into a cylindrical shape by pushing up the breast B from the tip with a push plate 33 made of an X-ray transparent material such as synthetic resin as shown in FIG. It is. The breast B in the breast container 15 is sucked with the negative pressure V1 and pulled to the vicinity of the rib R, and is pushed up from the tip of the breast B by the push plate 33 while maintaining the negative pressure V1, as shown in FIG. Thus, the breast B is pressed against the inner wall of the cylinder and shaped into a columnar shape. In addition, you may make it make the negative pressure V1 act on the breast B by supplying the negative pressure V1 in the mount 16 sealed using the breast container 15 which opened the bottom.

  When breast cancer screening is performed using the breast tomography apparatus 200 of the present embodiment, the subject P climbs on the top 12 and lies down so that the breast B falls into the hole 14 of the top 12 and the breast B However, it hangs down near the rotation axis A of the gantry 16 on which the X-ray generation device 20 and the X-ray detection device 18 are mounted, and fits in the cylindrical breast container 15. Thereafter, the breast B is pulled out of the chest wall by pulling the breast container 15 to the negative pressure V1, and, for example, the breast B is attracted to the inner wall with a negative pressure V2 higher than the negative pressure V1 of the breast container 15 to approximate a cylindrical shape.

  When the breast to be examined is ready, breast tomographic imaging is started. In tomographic imaging, while the gantry 16 rotates, the imaging unit 111 generates a trigger at every predetermined angle to radiate the cone beam C to the X-ray generation unit 113, and the X-ray detection unit 115 performs X-rays of the breast B. A transmission image is generated, an image signal is transmitted to the image processing unit 120, a tomographic image is generated by the image processing unit 120, and an X-ray tomographic image of the breast is viewed through the image display unit 140. During imaging, it is preferable to leave a negative pressure applied to stabilize the shape of the breast B. Breast cancer often occurs in the vicinity of the breast wall of the breast B. However, since the breast container 15 is pulled to the negative pressure V1 and the breast B is pulled out to the vicinity of the breast wall, tumors existing at the base of the breast B and oversight of calcification are not observed. Decrease.

  According to the present invention, an X-ray transmission image is acquired after reducing variation in X-ray transmission distance by shaping the shape from a breast to the tip of the breast using a breast container, so that a breast cancer can be obtained in a wide range in the breast. It was possible to provide a breast tomography apparatus capable of early detection.

It is a conceptual block diagram which showed notionally about the image acquisition part of the breast tomography apparatus which concerns on one Embodiment of this invention. It is a system block diagram explaining the whole structure of the breast tomography apparatus concerning this embodiment. It is drawing explaining the structural example of the breast accommodating part in embodiment. It is drawing explaining the mechanism which forms a cylindrical breast with the negative pressure apparatus in embodiment. It is drawing explaining another example of the breast columnarization means in this embodiment. It is drawing explaining the further another example of the breast columnarization means in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Top plate 14 The hole which passes a breast 15 Breast container 16 Base 18 X-ray detector 20 X-ray generator 22 Negative pressure controller 23 Cavity 25 Hole 29 Tape 27 Groove hole 31 Breast surface 33 Push plate 110 Image generation part 111 Imaging | photography Means 113 X-ray generation means 115 X-ray detection means 120 Image processing section 121 Image processing means 123 Image correction means 125 Image reconstruction means 127 Confirmation image generation means 129 Adjustment value calculation means 130 Image storage section 131 Image storage means 140 Image display section 141 Image display means 143 Confirmation image display means 151 Adjustment value input means 160 Imaging unit 161 Imaging unit control unit 163 Imaging unit rotation unit 165 Imaging unit lifting / lowering unit 167 X-ray detection unit translation unit 169 X-ray generation unit translation unit 170 Top plate unit 171 Top panel control means 170 Top panel 171 Top panel control Stage 173 top plate translating means 175 top plate elevating means 180 breast receiving portion 181 breast housing part controlling means 183 breast evacuation means 185 breast cylindrical means 200 breast tomographic imaging apparatus

Claims (5)

A top plate with a hole through which the breast passes and the subject lying on his / her face down and hanging the breast from the hole;
A cylindrical breast container that is placed under the hole and pulls the breast from the chest wall by receiving and pulling the breast hanging from the hole with negative pressure, and pulls the breast to the inner wall to approximate a cylindrical shape;
An X-ray generator that emits an X-ray cone beam;
An X-ray detector comprising a two-dimensional detector in which a plurality of X-ray detection elements for detecting the incident intensity of X-rays emitted from the X-ray generator are arranged on the surface;
A mount that mounts the X-ray generator and the X-ray detector at opposing positions and rotates around a rotation axis that passes through the hole;
A control device for controlling the movement of the top plate and the gantry and the operation of the X-ray generator and the X-ray detector;
A breast tomography apparatus comprising:   The breast tomography apparatus according to claim 1, wherein the breast container includes a negative pressure suction port in a body portion, and the breast is pulled into the inner wall to form a cylindrical shape.   The breast container is provided with a hole through which a string passes in the trunk, and by fixing one end of the string to the surface of the breast and pulling the other end through the hole, the breast is pulled to the inner wall to form a cylindrical shape. The breast tomographic imaging apparatus according to claim 1.   The breast tomographic imaging apparatus according to claim 1, wherein the breast container includes a push plate, and the breast is pushed up from the tip by the push plate, and the breast is pushed against the inner wall to have a cylindrical shape.   The breast tomography apparatus according to any one of claims 1 to 4, wherein the breast container includes a cylindrical diameter adjustment mechanism.