Mammography device

Abstract

To provide a mammography apparatus capable of executing appropriate projection on two surfaces with different projection distances while suppressing complication of the configuration.SOLUTION: A mammography apparatus includes: a radiographing platform; a radiation source; a compression plate for compressing the breast on the radiographing platform which is movable between the radiation source and the radiographing platform; a projector having a display unit for displaying an image including first information projected on a first face opposed to the radiation source in the radiographing platform and second information projected on a second face opposed to the radiation source in the compression plate, and a projection optical system in which the focus of the projection optical system is adjusted according to a projection distance to the first face; and a processor for controlling the display unit, which changes at least one of a display size and a display position of the second information in an image on an image display surface of the display unit according to the movement of the compression plate having the second face independently of the first information.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to a mammography apparatus. [Background Art]

[0002] Patent Document 1 discloses an X-ray diagnostic apparatus for mammography, comprising: X-ray exposing means for emitting X-rays; an X-ray flat panel detector for detecting X-rays incident on a detection surface; a compression plate for compressing and fixing a breast; and projection means for projecting a reference image, which is referred when fixing the breast by the compression plate, onto the compression plate or the detection surface. The technology described in Patent Document 1 describes that a reference image (e.g., a skin line) for positioning the breast is projected onto the compression plate or the detection surface using a projection means (e.g., a projector). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-236805 [Summary of Invention] [Problem to be Solved by the Invention]

[0004] There is a demand to display different information on the compression plate and the detection surface, respectively. However, the projection distance from the projector differs between the compression plate and the detection surface. Moreover, while the height of the detection surface is fixed and the projection distance is fixed, the height of the compression plate changes, so the projection distance also changes. In this case, as solutions for appropriately adjusting the projection magnification and focus of information projected onto each surface, it is conceivable to provide a focus adjustment mechanism depending on the position where an image is projected, or to use different projectors for different positions where an image is projected.

[0005] However, the configuration becomes complicated if a focus adjustment mechanism is provided depending on the projection location, or if different projectors are used for each projection location. The technology disclosed herein provides a mammography apparatus that can project appropriately onto two surfaces with different projection distances while suppressing the complexity of the configuration compared to cases without this configuration. [Means for solving the problem]

[0006] A first aspect of the technology of this disclosure is a mammography apparatus comprising: an imaging table on which a breast is placed; a radiation source that irradiates radiation toward the breast; a compression plate that compresses the breast on the imaging table, the compression plate being movable between the radiation source and the imaging table; a display unit that displays an image including first information projected onto a first surface facing the radiation source on the imaging table and second information projected onto a second surface facing the radiation source on the compression plate; a projector having a projection optical system that projects images toward the first surface and the second surface, and the focus of the projection optical system is adjusted according to the projection distance to the first surface; and a processor that controls the display unit, the processor which changes at least one of the display size or display position of the second information in the image on the image display surface of the display unit, independently of the first information, in accordance with the movement of the compression plate having the second surface.

[0007] A second aspect of the technology of this disclosure is a mammography apparatus according to the first aspect, wherein the display size and display position of the first information in the image are predetermined according to the projection distance to the first surface, and remain fixed even if the display size or display position of the second information changes.

[0008] A third aspect of the technology of this disclosure is a mammography apparatus according to the first aspect, wherein the focus of the projection optical system is adjusted within a range between a first plane and a position closer to the projector side from the first plane by a statistically determined breast thickness.

[0009] A fourth aspect of the technology of this disclosure is a mammography apparatus according to the third aspect, wherein the focus of the projection optical system is adjusted to the first plane.

[0010] A fifth aspect of the technology of this disclosure is a mammography apparatus according to the first aspect, wherein the second surface of the compression plate is subjected to a light transmission suppression treatment that suppresses the transmission of light to the area on which the second information is projected.

[0011] A sixth aspect of the technology of this disclosure is a mammography apparatus according to the first aspect, wherein the first information is a skin line indicating the contour of the breast, which serves as a guide when the breast is placed on the apparatus.

[0012] A seventh aspect of the technology of this disclosure is a mammography apparatus according to the first aspect, wherein the second information is the imaging conditions when imaging a breast. [Effects of the Invention]

[0013] The technology disclosed herein can provide a mammography apparatus that enables appropriate projection onto two planes with different projection distances while suppressing complexity of the configuration. [Brief explanation of the drawing]

[0014] [Figure 1] This is an external perspective view showing an example of the configuration of a mammography system. [Figure 2] This is an external side view showing an example of the configuration of a mammography system. [Figure 3] This is a block diagram showing an example of the configuration of a mammography system. [Figure 4] This is a side view showing an example of image projection in a mammography device. [Figure 5] This is a schematic diagram showing an example of image projection in a mammography device. [Figure 6] This is a plan view showing an example of a projected image from a mammography device. [Figure 7] This is a side view showing an example of image projection in a mammography device. [Figure 8] This is a functional block diagram showing an example of image generation processing in a processor. [Figure 9] This diagram illustrates the projection position, display position, size, and focus in a mammography apparatus. [Figure 10] It is a side view showing an example of image projection in a mammography apparatus. [Figure 11] It is a side view showing an example of image projection in a mammography apparatus. Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0016] As shown in FIG. 1 and FIG. 2, the mammography apparatus 10 according to the first embodiment is a radiation imaging apparatus that captures a radiation image of a breast M (see FIG. 4) of a subject serving as an object by irradiating radiation to the breast M. The radiation is X-ray as an example, but may also be γ-ray.

[0017] The mammography apparatus 10 is connected to a console (not shown). In addition to a setting function of setting the mammography apparatus 10 in accordance with an imaging order, the console has a function of acquiring a radiation image captured by the mammography apparatus 10 and displaying the acquired radiation image. The console is communicably connected to an image database server (not shown) via a network (not shown) such as a LAN (Local Area Network).

[0018] The mammography apparatus 10 includes a stand 20 and an arm 21. The stand 20 is composed of a pedestal 20A installed on the floor of a radiography room and a support column 20B extending in the height direction from the pedestal 20A. The arm 21 has a substantially C-shaped shape when viewed from the side, and is connected to the support column 20B. Since the arm 21 is movable in the height direction relative to the support column 20B, height adjustment according to the height of the subject can be performed. In addition, the arm 21 is rotatable around a rotation axis perpendicular to the support column 20B.

[0019] The arm 21 consists of a radiation source housing 22, a main body 23, and an imaging table 24. The radiation source 22 houses a radiation source 25. The imaging table 24 is on which the subject's breast M is placed. The imaging table 24 is an example of an "imaging table" according to the technology of this disclosure. The imaging table 24 houses a radiation detector 26. The main body 23 integrally connects the radiation source housing 22 and the imaging table 24. The main body 23 holds the radiation source housing 22 and the imaging table 24 in opposing positions. Handrails 27 for the subject to grasp are provided on both sides of the main body 23.

[0020] The radiation source 25 irradiates radiation toward the breast M placed on the imaging table 24. The radiation source 25 is an example of a "radiation source" related to the technology of this disclosure. The radiation emitted from the radiation source 25 passes through the compression plate 30 and then enters the breast M. The radiation detector 26 detects the radiation that has passed through the breast M and outputs a radiation image. The radiation detector 26 is called an FPD (Flat Panel Detector). The radiation detector 26 has a scintillator that converts radiation into visible light, and may be an indirect conversion type that converts the visible light emitted by the scintillator into an electrical signal, or a direct conversion type that directly converts radiation into an electrical signal.

[0021] A field of irradiation limiter 31 is provided between the radiation source housing 22 and the imaging table 24. The field of irradiation limiter 31, also called a collimator, defines the field of radiation irradiation to the imaging table 24.

[0022] A face guard 32 is attached to the radiation source housing 22. The face guard 32 is made of or coated with a material that does not transmit radiation, and protects the subject's face from radiation.

[0023] A compression plate 30 is provided between the imaging table 24 and the irradiation field limiter 31 to compress the breast M between the imaging table 24 and the compression plate 30. The compression plate 30 is an example of a "compression plate" according to the technology of this disclosure. The compression plate 30 is made of a material that allows radiation to pass through. The compression plate 30 is positioned opposite the imaging table 24. In this embodiment, the compression plate 30 is box-shaped with an open top. The compression plate 30 may also be in other shapes, such as a flat plate shape.

[0024] A projector 14 is housed in the radiation source housing 22. The projector 14 projects an image toward the imaging surface 24A of the imaging table 24. Here, the imaging surface 24A is the surface of the imaging table 24 that faces the radiation source 25. The projector 14 also projects an image toward the surface of the compression plate 30 that faces the radiation source 25. Since the compression plate 30 in this embodiment is box-shaped, the bottom surface 30A of the box is the surface that faces the radiation source 25. The projector 14 projects an image toward the bottom surface 30A of the compression plate 30. The projector 14 is an example of a "projector" according to the technology of this disclosure. The imaging surface 24A is an example of a "first surface" according to the technology of this disclosure, and the bottom surface 30A is an example of a "second surface" according to the technology of this disclosure.

[0025] The drive mechanism 35 supports the compression plate 30 so that it can move between the radiation source 25 and the imaging table 24. The movable part 34 is positioned between the compression plate 30 and the drive mechanism 35. The movable part 34 is slidably held on a rail 28 provided on the drive mechanism 35. The rail 28 extends in the vertical direction.

[0026] The compression plate 30 is attached to the movable part 34. The movable part 34 moves vertically together with the compression plate 30 by a drive mechanism 35, which will be described later. Functionally, the vertical direction is the direction in which the compression plate 30 moves toward the imaging table 24 (downward) and the direction in which the compression plate 30 moves away from the imaging table 24 (upward). In this way, the compression plate 30 is configured to be movable in a manner that changes the distance between it and the imaging table 24.

[0027] As shown in Figure 3, the mammography apparatus 10 is equipped with a control device 16. The control device 16 comprehensively controls the operation of each part of the mammography apparatus 10, including the radiation source 25, radiation detector 26, arm 21, drive mechanism 35, and projector 14. In Figure 3, the control objects of the control device 16 are limited to the drive mechanism 35 and projector 14, and the others are omitted.

[0028] The control device 16 includes, for example, a processor 16A, a RAM (Random Access Memory) 16B, an NVM (Non-volatile memory) 16C, and an external I / F (Interface) 16D. The processor 16A, RAM 16B, NVM 16C, and external I / F 16D are electrically connected via a bus 16E. The processor 16A is an example of a "processor" related to the technology of this disclosure.

[0029] Processor 16A is, for example, a CPU (Central Processing Unit) that controls various parts and performs image processing as described later. RAM 16B is memory that temporarily stores information and is used as work memory by processor 16A. NVM 16C is a non-volatile storage device that stores various programs and parameters. An example of NVM 16C is flash memory (for example, EEPROM (Electrically Erasable and Programmable Read Only Memory) and / or SSD (Solid State Drive)). Note that flash memory is merely an example, and other non-volatile storage devices such as HDD (Hard Disk Drive) may be used, or a combination of two or more types of non-volatile storage devices may be used.

[0030] The external I / F 16D is responsible for the exchange of information between the control device 16 and the projector 14 and the drive mechanism 35. For example, the external I / F 16D outputs a signal to the projector 14 to emit projection light L representing the image to be projected. The external I / F 16D also outputs a signal to the drive mechanism 35 to control the operation of the drive mechanism 35.

[0031] The projector 14 includes a display unit 14A that displays the image to be projected, and a projection optical system 14D that magnifies and projects the image displayed on the display unit 14A (see also Figure 4). The control device 16 controls the display of the image on the image display surface 14A1 of the display unit 14A. The display unit 14A is an example of a "display unit" according to the technology of this disclosure, and the image display surface 14A1 is an example of an "image display surface" according to the technology of this disclosure. Examples of the display unit 14A include a DMD (Digital Micromirror Device) or an LCD (Liquid Crystal Display). As is well known, a DMD has multiple micromirrors corresponding to multiple pixels. For example, by changing the angle of each micromirror, the reflection direction of light from the light source is changed to on-light that is incident on the projection optical system 14D and off-light that is not incident on the projection optical system 14D. The amount of light for each pixel is adjusted by the duration of the on-light. In this way, by changing the angle of multiple micromirrors corresponding to multiple pixels, optical modulation is performed to load the information of the image to be projected onto the projection light L. If the display unit 14A is a DMD, the array surface in which multiple micromirrors are arranged in two dimensions corresponds to the image display surface 14A1, and the control of the micromirrors according to the projected image corresponds to image display. As is well known, an LCD has multiple liquid crystal cells corresponding to multiple pixels, and by changing the light transmission state from the light source for each liquid crystal cell, light modulation according to the projected image is performed. If the display unit 14A is an LCD, the array surface in which multiple liquid crystal cells are arranged in two dimensions corresponds to the image display surface 14A1. In Figures 3 and 4, the display unit 14A is schematically shown, but the display unit 14A includes a light source. Alternatively, the display unit 14A may be one in which self-emissive light-emitting elements such as organic EL are arranged in two dimensions and this functions as the image display surface 14A1.

[0032] The projection light L emitted from the display unit 14A enters the projection optical system 14D, passes through the projection optical system 14D, and is projected onto the bottom surface 30A of the compression plate 30. The projection light L that has passed through the compression plate 30 is projected onto the imaging surface 24A of the imaging table 24. The projection optical system 14D is composed of multiple optical elements and magnifies the image generated in the display unit 14A and projects it toward the compression plate 30 and the imaging table 24. The projection optical system 14D is composed of an internal optical system 14B built into the main body of the projector 14 and optical elements arranged outside the main body of the projector 14. For example, the internal optical system 14B includes one or more lenses 14B1 as optical elements. In this example, the optical element arranged outside the main body is a mirror 14C. The mirror 14C is positioned, for example, at a 45° inclination with respect to the optical axis of the built-in optical system 14B, and changes the path of the projection light L emitted from the built-in optical system 14B by 90° toward the compression plate 30 and the imaging table 24. The focus of the projection optical system 14D is pre-adjusted according to the projection distance to the imaging surface 24A of the imaging table 24. The built-in optical system 14B is an example of a "projection optical system" according to the technology of this disclosure. Here, the description has given an example in which the focus of the projection optical system 14D is pre-adjusted before the projection of the image, but the technology of this disclosure is not limited to this. It is sufficient that the image is projected with the focus adjusted according to the projection distance to the imaging surface 24A of the imaging table 24, and for example, the focus adjustment may be performed within a predetermined time (for example, 2 to 3 seconds) from the start of projection.

[0033] The drive mechanism 35 includes a motor driver 35A, a motor 35B, and an encoder 35C. The motor driver 35A operates the motor 35B based on a signal output from the processor 16A via an external I / F 16D. The motor 35B rotates in response to the electrical drive signal output by the motor driver 35A, moving the compression plate 30 via a power transmission mechanism (e.g., a lead screw mechanism) not shown. The encoder 35C converts the mechanical displacement of the motor 35B's rotation into an electrical signal and outputs it to the processor 16A.

[0034] Encoder 35C is used to detect the amount of movement of the compression plate 30. Encoder 35C is, for example, a rotary encoder that combines a rotating plate, which has multiple light-transmitting small holes arranged at regular intervals around its circumference and rotates with the rotation axis of the motor 35B, with a photosensor. As is well known, a rotary encoder receives pulsed light intermittently output from the small holes as the rotating plate rotates with the photosensor and outputs an encoder pulse corresponding to the number of pulsed lights received. An encoder pulse is an example of an electrical signal that represents the amount of mechanical displacement of the rotation of the motor 35B. The processor 16A derives the amount of rotation of the motor 35B by counting the encoder pulses and detects the amount of movement of the compression plate 30 from the derived amount of rotation. Note that instead of a rotary encoder, encoder 35C may be a linear encoder that detects the amount of movement of the compression plate 30. Alternatively, a pulse motor may be used as the motor 35B, and the amount of movement of the compression plate 30 may be detected by counting the drive pulses that the processor 16A outputs to the motor 35B.

[0035] As shown in Figures 4 and 5, the mammography apparatus 10 projects information onto the imaging surface 24A and the bottom surface 30A of the compression plate 30 by emitting projection light L from the projector 14. The projector 14 is capable of projecting different information onto the imaging surface 24A and the bottom surface 30A of the compression plate 30.

[0036] Image condition information 50, which indicates the imaging conditions, is projected onto the bottom surface 30A of the compression plate 30. Imaging conditions include, for example, the current compression pressure on the breast M, the compression thickness t, or the type of imaging procedure. The compression pressure is determined, for example, by measuring the reaction force applied to the compression plate 30 when the breast M is compressed with the compression plate 30 using a pressure measuring device (not shown). The pressure measuring device is provided, for example, on the imaging table 24. The compression thickness t is determined by measuring the height of the compression plate 30 relative to the imaging surface 24A when the breast M is compressed. The height of the compression plate 30 is measured, for example, based on the amount of movement of the compression plate 30 detected by the encoder 35C. Examples of imaging procedures include CC imaging (Cranio-Caudal), in which the breast M is compressed and imaged from the head-to-tail direction of the subject, and MLO imaging (Medio-Lateral), in which the breast M is compressed and imaged from a direction inclined relative to the head-to-tail direction of the subject. The imaging procedure is, for example, entered in advance by the operator. Other imaging conditions include, for example, past imaging conditions (compression pressure, compression thickness t, and type of imaging procedure). Further imaging conditions include information that can identify the subject (for example, the subject's name, gender, age, or subject ID (identification)). Further imaging conditions include information related to the mammography examination (date and time of examination, person performing the examination, radiation exposure time, or output of the radiation source or tube voltage during radiation exposure). The imaging condition information 50 is an example of the "second information" relating to the technology of this disclosure.

[0037] On the bottom surface 30A of the compression plate 30, the area 51 onto which the shooting condition information 50 is projected is treated to suppress light transmission. In the example shown in Figure 6, the area 51 onto which the shooting condition information 50 is projected is roughened. This makes it more difficult for the projected light L representing the shooting condition information 50 to pass through the compression plate 30, and increases the amount of reflected light on the compression plate 30. As a result, the shooting condition information 50 is clearly visible on the compression plate 30. Here, one example of a roughening treatment is blasting. Another example of a treatment to suppress light transmission is to attach an opaque material to the area 51 on the compression plate 30 onto which the shooting condition information 50 is projected. For example, a seal may be attached to the area 51 of the compression plate 30.

[0038] The portion of the compression plate 30 other than the region 51 is made of a material transparent to the projected light L. Therefore, the projected light L that passes through the compression plate 30 is projected onto the imaging surface 24A. On the imaging surface 24A, a skin line 24B is projected that indicates the contour of the breast M, which serves as a guide when placing the breast M. The contour of the breast M indicated by the skin line 24B is obtained by extracting the contour of the breast M from examination images taken in past examinations. Since the relative positional relationship between the imaging surface 24A and the detection surface of the radiation detector 26 is known, the projection position of the skin line 24B to be projected on the imaging surface 24A can be derived from the position of the skin line that appears in the examination image detected by the radiation detector 26. By displaying the skin line 24B from past examinations in this way, it becomes possible to photograph the breast M at the same position as in past examinations, which is effective when performing follow-up observations. The skin line 24B is an example of "First Information" relating to the technology of this disclosure. The subject's breast M is positioned by the user on the imaging surface 24A of the imaging table 24. With the breast M positioned, it is compressed by the compression plate 30. As shown in Figures 5 and 6, imaging condition information 50 is projected onto the compression plate 30, and skin lines 24B are projected onto the imaging surface 24A. Alternatively, instead of the skin lines 24B, or together with the skin lines 24B, a mark indicating the position of the nipple of the breast M (for example, a cross mark with an intersection at the nipple position) may be projected onto the imaging surface 24A.

[0039] The projection magnification of the projection optical system 14D is set, for example, so that the largest image that can be displayed on the image display surface 14A1 fits within the range of the imaging surface 24A. Therefore, all of the information displayed on the image display surface 14A1 that is carried by the projection light L that reaches the imaging surface 24A is projected onto the imaging surface 24A.

[0040] Here, as shown in Figure 7, the compression plate 30 moves in the vertical direction (along the Z direction shown in Figure 7). This changes the distance between the compression plate 30 and the projector 14. Therefore, even if the projection magnification of the projection optical system 14D is fixed, the projection distance of the image from the projector 14 to the compression plate 30 changes, and thus the projection range R on the compression plate 30 changes. More specifically, the display size of the shooting condition information 50 on the compression plate 30 changes. For example, the display size of the shooting condition information 50 is smallest on the side of the compression plate 30 closest to the projector 14, and increases as it moves away from the projector 14. The display size of the shooting condition information 50 is largest at the position furthest from the projector 14. In addition, depending on the direction in which the light beam of projection light L is incident on the compression plate 30, the display position within the compression plate 30 may change due to the change in display size. As a result of the movement of the compression plate 30, at least one of the display size and display position of the shooting condition information 50 changes, causing the shooting condition information 50 to protrude from the compression plate 30 or to be too small to read. Consequently, the visibility of the shooting condition information 50 to the user is reduced.

[0041] On the other hand, on the imaging surface 24A, the projection distance from the projector 14 is constant, so the display size of the skin line 24B projected from the projector 14 does not change. Also, as mentioned above, the focus of the projection optical system 14D of the projector 14 is pre-adjusted according to the distance to the imaging surface 24A. The focus of the projection optical system 14D is optically set based on, for example, the arrangement of the optical elements of the projection optical system 14D and the distance between the imaging surface 24A and the projector 14. For example, the focus of the projection optical system 14D is adjusted within a range between the imaging surface 24A and a position close to the projector 14 by a statistically determined thickness t of the breast M. Here, the statistically determined thickness t of the breast M is, for example, the average value of the breast thickness t of multiple subjects, but this is only one example. For example, the statistically determined thickness t of the breast M may be the mode or median of the breast thickness t of multiple subjects. In this example, the projection optical system 14D is in focus on the imaging plane 24A.

[0042] Thus, in the mammography apparatus 10, imaging condition information 50 is projected onto the compression plate 30, where the projection distance from the projector 14 changes, and the skin line 24B is projected onto the imaging surface 24A, where the projection distance does not change. In this case, for example, it is conceivable to mount two projectors on the mammography apparatus 10: one for projecting the imaging condition information 50 onto the compression plate 30, and another for projecting the skin line 24B onto the imaging surface 24A. However, this would complicate the configuration of the mammography apparatus 10.

[0043] Therefore, in the mammography apparatus 10 according to this embodiment, the processor 16A controls the display unit 14A of a single projector 14 to achieve appropriate projection onto two surfaces with different projection distances, such as projecting skin lines 24B onto the imaging surface 24A and imaging condition information 50 onto the bottom surface 30A of the compression plate 30. First, the information displayed on the display unit 14A of the projector 14 is an image 52 that includes imaging condition information 50 and skin lines 24B (see Figures 8, 10, and 11). The processor 16A controls the display unit 14A to change the display size and position of the imaging condition information 50 of the image 52 on the image display surface 14A1 independently of the display size and position of the skin lines 24B, in accordance with the movement of the compression plate 30. The processor 16A also pre-sets the display size and position of the skin lines 24B of the image 52 on the image display surface 14A1 of the display unit 14A.

[0044] As shown in Figure 8 as an example, the processor 16A performs image generation processing to generate an image 52 to be displayed on the display unit 14A. First, the processor 16A acquires imaging condition information 50 for the image 52. For example, the processor 16A acquires the compression thickness t and compression force of the imaging condition information 50 from the measured value of the pressure measuring instrument and the height of the compression plate 30. The processor 16A also acquires the imaging procedure from the operator's input information. The processor 16A also acquires skin line 24B information (coordinate information representing the shape and position of the skin line 24B) derived from previously taken breast M examination images. Then, the processor 16A generates images 52A and 52B representing the acquired imaging condition information 50 and skin line 24B. Finally, the processor 16A combines the two images 52A and 52B to generate image 52 which includes the imaging condition information 50 and skin line 24B.

[0045] Furthermore, the processor 16A adjusts the display size and position of the shooting condition information 50 within the generated image 52 according to the position of the compression plate 30 and the projection range R on the compression plate 30. On the other hand, since the projection distance to the shooting surface 24A is fixed, the display size and position of the skin lines 24B projected onto the shooting surface 24A within the image 52 are not adjusted according to the position of the compression plate 30. In other words, the processor 16A adjusts the display size and position of the shooting condition information 50 independently of the adjustments to the display size and position of the skin lines 24B within the image 52.

[0046] As described above, the processor 16A detects the amount of movement of the compression plate 30 by counting encoder pulses from the encoder 35C (see Figure 3) of the drive mechanism 35. Then, it determines the position of the compression plate 30 according to the detected amount of movement. Based on the position of the compression plate 30, the processor 16A adjusts the display size and display position of the shooting condition information 50 in the image 52. In this way, an image 52 corresponding to the position of the compression plate 30 (i.e., the height from the shooting surface 24A) is generated. In Figure 8, the image 52 generated by the image generation process according to height shows how the display position and display size of the shooting condition information 50 change according to the position of the compression plate 30.

[0047] The processor 16A outputs a signal to the display unit 14A of the projector 14 indicating an image 52 corresponding to the position of the compression plate 30. Based on the signal received from the processor 16A, the display unit 14A displays the image 52 on the image display surface 14A1. The projector 14 then emits projection light L representing the image 52 via its built-in optical system 14B.

[0048] Figure 9 summarizes the projection conditions for each piece of information projected by the projector 14, namely the projection location, focus, display position, and display size, as described above. First, the projection location for the skin line 24B is the shooting surface 24A, and the display position and size of the skin line 24B within the image 52 are fixed. On the other hand, the projection location for the shooting condition information 50 is the bottom surface 30A of the compression plate 30, and the display position and size are adjusted according to the height of the compression plate 30. Specifically, the lower the position of the compression plate 30 (i.e., the height from the shooting surface 24A), the longer the projection distance. As the projection distance increases, the magnification of the image 52 relatively increases, and taking this increase into account, the display size of the image 52 displayed on the display unit 14A becomes smaller. Also, the higher the position of the compression plate 30, the shorter the projection distance. As the projection distance decreases, the magnification of the image 52 relatively decreases, and taking this decrease into account, the display size of the image 52 displayed on the display unit 14A becomes larger. Furthermore, the focus of the projection optical system 14D in the projector 14 is fixed by adjusting it within a range between the imaging surface 24A and a position close to the projector 14, which is a statistically determined thickness t of the breast M. The projection magnification of the projection optical system 14D is also fixed.

[0049] Next, the operation of the mammography apparatus 10 according to this embodiment will be explained with reference to Figures 10 and 11. As shown in Figure 10, first consider the state in which the compression plate 30 is in the position closest to the projector 14 (i.e., distance h1 from the imaging surface 24A). In this case, the display size and position of the skin line 24B in image 52 on the image display surface 14A1 of the display unit 14A are set in advance. For example, if the skin line 24B indicates the position of the breast M placed on the imaging surface 24A in a previous imaging, the display size of the skin line 24B in image 52 is adjusted so that it is equal to the actual size of the breast on the imaging surface 24A. Also, the display position of the skin line 24B in image 52 is adjusted to be the same position as the position of the breast M placed on the imaging surface 24A in a previous imaging. The display position and display size of the skin line 24B thus adjusted remain fixed even if the position of the compression plate 30 changes. In other words, as will be described later, even if the display size or position of the shooting condition information 50 changes in accordance with the movement of the compression plate 30, the display size and position of the skin line 24B remain fixed.

[0050] On the other hand, in image 52 on the image display surface 14A1, the display size and position of the shooting condition information 50 are adjusted according to the position of the compression plate 30 (i.e., the distance h1 from the shooting surface 24A). Since the compression plate 30 is in the position closest to the projector 14, the display size of the shooting condition information 50 is adjusted to be the largest possible within image 52. Also, if the display position needs to be adjusted by the compression plate 30, the display position of the shooting condition information 50 is also changed. For example, there are cases where it is desirable to project the shooting condition information 50 onto the compression plate 30 as far away from the breast M as possible, that is, on the anti-chest wall side (the opposite side of the subject's chest wall). In this case, if the display size of the shooting condition information 50 is relatively reduced, a gap will be created on the anti-chest wall side of the compression plate 30, so the display position of the shooting condition information 50 is moved towards the anti-chest wall side to fill that gap.

[0051] Then, the image 52 is projected from the projector 14 onto the compression plate 30 and the imaging surface 24A. On the compression plate 30, imaging condition information 50 is projected, whose display size and display position are adjusted according to the position of the compression plate 30. For example, the imaging condition information 50 is projected into a region 51 that has been treated to suppress the transmission of light from the compression plate 30. Also, skin lines 24B are projected onto the imaging surface 24A. Since the focus of the projector 14's built-in optical system 14B is set on the imaging surface 24A, the skin lines 24B are projected onto the imaging surface 24A in focus.

[0052] In this case, since the focus is on the skin line 24B, the contour of the breast M can be aligned with the skin line 24B. Also, since the shooting condition information 50 is projected onto the compression plate 30, the user can check the shooting conditions while aligning the breast M. In this case, the shooting condition information 50 projected onto the compression plate 30 is out of focus. However, since the compression plate 30 is located on the near side of the in-focus shooting surface 24A, the degree of blurring is less compared to the far side of the in-focus position. Therefore, it is possible to project the shooting conditions appropriately with good visibility.

[0053] Next, as shown in Figure 11, the compression plate 30 moves to a position away from the projector 14 (i.e., the distance h2 from the imaging surface 24A).

[0054] ​Within image 52, the display size and position of the shooting condition information 50 are adjusted according to the position of the compression plate 30 (i.e., the distance h2 from the shooting surface 24A). Because the compression plate 30 has moved to a position further away from the projector 14 (i.e., from distance h1 to distance h2 from the shooting surface 24A), the projection distance to the compression plate 30 increases. Accordingly, the display size of the shooting condition information 50 within image 52 is adjusted to decrease in proportion to the increased projection distance to the compression plate 30. In addition, if a change in the display position is necessary in conjunction with the adjustment of the display size of the shooting condition information 50, the display position of the shooting condition information 50 is also changed. For example, the processor 16A adjusts the display size and position of the shooting condition information 50 within image 52 on the image display surface 14A1 by controlling the display unit 14A according to the position of the compression plate 30 and the projection range on the compression plate 30.

[0055] Then, the image 52 is projected from the projector 14 onto the compression plate 30 and the imaging surface 24A. On the compression plate 30, imaging condition information 50 is projected, with the display size and position adjusted according to the position of the compression plate 30. That is, the imaging condition information 50 is displayed on the compression plate 30 with the same display size and position as before the compression plate 30 moved. For example, the imaging condition information 50 is projected into a region 51 that has been treated to suppress the transmission of the compression plate 30. Also, skin lines 24B are projected onto the imaging surface 24A. Since the focus of the projector 14's built-in optical system 14B is set to the imaging surface 24A, the skin lines 24B are projected onto the imaging surface 24A in focus.

[0056] In this case, since the focus is on the skin line 24B, the contour of the breast M can be aligned with the skin line 24B. Also, since the shooting condition information 50 is projected onto the compression plate 30, the user can check the shooting conditions while aligning the breast M. In this case, the display size and display position of the shooting condition information 50 projected onto the compression plate 30 are adjusted according to the position of the compression plate 30. Therefore, the shooting condition information 50 can be displayed in the same area while the breast M is being compressed by the compression plate 30. As a result, it is possible to project the shooting conditions appropriately with good visibility.

[0057] In this explanation, we have described the case where the compression plate 30 is in the position closest to the projector 14 (i.e., distance h1 from the imaging surface 24A) and the position where the compression plate 30 is compressing the breast M (i.e., distance h2 from the imaging surface 24A). However, even when the compression plate 30 is in a position other than these, the display size and position of the imaging condition information 50 are adjusted. In other words, when the compression plate 30 moves between the radiation source 25 and the imaging table 24, the display size and position of the imaging condition information 50 are adjusted according to the movement of the compression plate 30.

[0058] As described above, the mammography apparatus 10 according to this embodiment makes it possible to project the imaging condition information 50 while maintaining visibility without complicating the projector 14 or projection optical system, compared to the case where both focus adjustment and projection position and size adjustment are performed for each of the skin line 24B projected onto the imaging table 24 and the imaging condition information 50 projected onto the compression plate 30. In other words, the focus of the built-in optical system 14B of the projector 14 is adjusted according to the projection distance to the imaging surface 24A. This makes it possible to simplify the configuration of the projector 14. Furthermore, when projecting two pieces of information with different projection distances (i.e., imaging condition information 50 and skin line 24B) with one projector 14, if one side is focused on the near-distance side and the other side is focused on the far-distance side, the degree of blurring on the near-distance side is less when the far-distance side is focused on. Therefore, by adjusting the focus to the imaging table 24 side on which the skin line 24B is projected, as in the above configuration, the decrease in visibility of the imaging condition information 50 can be suppressed.

[0059] Furthermore, in the mammography apparatus 10 according to this embodiment, the display size and position of the skin line 24B projected onto the imaging surface 24A are preset according to the projection distance to the imaging surface 24A. This simplifies the configuration of the projector 14 compared to the case where the display size and position of the skin line 24B are adjusted in addition to the imaging condition information 50.

[0060] Furthermore, according to the mammography apparatus 10 of this embodiment, the focus of the built-in optical system 14B is adjusted within a range between the imaging surface 24A and a position closer to the projector 14 side from the imaging surface 24A by the statistically determined thickness t of the breast M. Since the focus is adjusted within the above range, it is possible to ensure good visibility with a good balance between the skin line 24B and the imaging condition information 50 compared to when the focus is adjusted outside the above range.

[0061] Furthermore, in the mammography apparatus 10 according to this embodiment, since the focus is set on the imaging surface 24A, good visibility of the skin line 24B can be ensured compared to when the focus is set on a surface other than the imaging surface 24A.

[0062] Furthermore, in the mammography apparatus 10 according to this embodiment, the compression plate 30 is subjected to a light transmission suppression process that suppresses the transmission of projected light L to the area on which the imaging condition information 50 is projected. As a result, the visibility of the imaging condition information 50 projected onto the compression plate 30 is improved compared to the case where the light transmission suppression process is not performed.

[0063] Furthermore, in the mammography apparatus 10 according to this embodiment, the information projected onto the imaging surface 24A is a skin line 24B that indicates the contour of the breast M, which serves as a guide when placing the breast M on the imaging table 24. Since the skin line 24B is displayed on the imaging surface 24A, the positioning accuracy when placing the breast M on the imaging table 24 is improved compared to when the skin line 24B is not displayed.

[0064] Furthermore, in the mammography apparatus 10 according to this embodiment, the imaging condition information 50 is the imaging condition when imaging the breast M. Since the imaging condition is displayed on the compression plate 30, it becomes easier to check the imaging condition compared to when the imaging condition is not displayed.

[0065] In the above embodiment, an example was described in which both the display size and display position of the shooting condition information 50 are adjusted in accordance with the movement of the compression plate 30, but the technology of this disclosure is not limited thereto. Either the display size or the display position of the shooting condition information 50 may be adjusted in accordance with the movement of the compression plate 30.

[0066] Furthermore, although the above embodiment described an example in which the display size and position of the skin line 24B are pre-set within the image 52 on the image display surface 14A1 of the display unit 14A, the technology of this disclosure is not limited thereto. For example, the display size and position of the skin line 24B may be adjusted based on user input after they have been set.

[0067] Furthermore, although the above embodiment described an example in which the imaging condition information 50 is projected onto the compression plate 30 and the skin line 24B is displayed on the imaging surface 24A, the technology of this disclosure is not limited thereto. For example, the imaging condition information 50 and the skin line 24B may be displayed on the compression plate 30. In this case, the area of ​​the compression plate 30 where the skin line 24B is displayed is also subjected to a transmission suppression treatment. However, in this case, the breast M becomes difficult to see through the compression plate 30, so the embodiment described above, in which the projected light L is transmitted through the compression plate 30 and the skin line 24B is displayed on the imaging surface 24A, is more preferable.

[0068] The above-mentioned processors include not only CPUs but also GPUs (Graphics Processing Units). Furthermore, the above-mentioned processors are not limited to general-purpose processors such as CPUs that execute software (programs) and function as various processing units, but also include programmable logic devices (PLDs) such as FPGAs (Field Programmable Gate Arrays), which are processors whose circuit configuration can be changed after manufacturing, and dedicated electrical circuits such as ASICs (Application Specific Integrated Circuits), which are processors with circuit configurations specifically designed to perform specific processing.

[0069] Furthermore, the hardware structure of these various processors can, more specifically, utilize electrical circuits that combine circuit elements such as semiconductor devices. .

[0070] The descriptions and illustrations presented above are detailed explanations of the technical aspects of this disclosure and are merely examples of the technical aspects. For example, the above descriptions of the structure, function, operation, and effect are examples of the structure, function, operation, and effect of the technical aspects of this disclosure. Therefore, it goes without saying that you may delete unnecessary parts, add new elements, or replace elements in the descriptions and illustrations presented above, as long as you do not deviate from the essence of the technical aspects of this disclosure. Furthermore, in order to avoid confusion and facilitate understanding of the technical aspects of this disclosure, explanations of common technical knowledge and the like that do not require special explanation to enable the implementation of the technical aspects of this disclosure have been omitted from the descriptions and illustrations presented above.

[0071] All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

[0072] The following additional information is disclosed regarding the above embodiment. <Note 1> A table on which the breasts are placed, A radiation source that irradiates the above-mentioned breast, A compression plate for compressing the breast on the above-mentioned imaging table, comprising a compression plate that is movable between the radiation source and the above-mentioned imaging table, A projector having a display that shows an image including first information projected onto a first surface facing the radiation source on the above-mentioned imaging table and second information projected onto a second surface facing the radiation source on the above-mentioned compression plate, and a projection optical system that projects the above-mentioned image toward the first surface and the second surface, wherein the focus of the projection optical system is adjusted according to the projection distance to the first surface, A processor for controlling the above-mentioned display device, comprising: a processor that changes at least one of the display size or display position of the second information in the image on the image display surface of the display device, independently of the first information, in accordance with the movement of the compression plate having the second surface; Mammography device. <Note 2> The display size and position of the first piece of information in the image above are predetermined according to the projection distance to the first surface, and remain fixed even if the display size or position of the second piece of information changes. The mammography apparatus described in Appendix 1. <Note 3> The focus of the projection optical system is adjusted within a range between the first surface, the statistically determined thickness of the breast, and a position closer to the projector side from the first surface. A mammography apparatus as described in Appendix 1 or Appendix 2. <Note 4> The focus of the above projection optical system is adjusted to the first surface. A mammography device as described in any one of the appendices 1 to 3. <Note 5> On the second surface of the compression plate described above, a light transmission suppression treatment is applied to suppress the transmission of light to the area on which the second information is projected. A mammography device as described in any one of the appendices 1 through 4. <Note 6> The first piece of information above is a skin line indicating the contour of the breast, which serves as a guide when placing the breast. A mammography device as described in any one of the appendices 1 through 5. <Note 7> The second piece of information above refers to the shooting conditions when photographing the breasts described above. A mammography device as described in any one of the appendices 1 through 6. [Explanation of Symbols]

[0073] 10. Mammography device 14 Projectors 14A display 14A1 Image display surface 14B Built-in Optical System 14B1 Lens 14C Mirror 14D projection optical system 16 Control device 16A Processor 16B RAM 16C NVM 16D External I / F 16E Bus 20 stands 20A Base 20B Post 21 Arms 22 Source housing 23 Main body 24 Shooting platform 24A Imaging surface 24B Skinline 25 Radiation source 26 Radiation detectors 28 rails 30 Compression plate 30A Bottom 31 Irradiation field limiter 32 Face Guards 34 Moving parts 35 Drive mechanism 35A Motor Driver 35B motor 35C encoder 50 Shooting Conditions Information 51 areas Images 52, 52A, 52B L projection light M Breast t Breast compression thickness h1 distance h2 distance R projection range

Claims

1. A table on which the breasts are placed, A radiation source that irradiates the breast with radiation, A compression plate for compressing the breast on the imaging table, and a compression plate that is movable between the radiation source and the imaging table, A projector having a display that shows an image including first information projected onto a first surface facing the radiation source on the imaging table and second information projected onto a second surface facing the radiation source on the compression plate, and a projection optical system that projects the image toward the first surface and the second surface, wherein the focus of the projection optical system is adjusted according to the projection distance to the first surface, A processor for controlling the display device, comprising a processor that changes at least one of the display size or display position of the second information in the image on the image display surface of the display device, independently of the first information, in accordance with the movement of the compression plate having the second surface. Mammography device.

2. The display size and position of the first information in the aforementioned image are predetermined according to the projection distance to the first surface, and remain fixed even if the display size or position of the second information changes. The mammography apparatus according to claim 1.

3. The focus of the projection optical system is adjusted within a range between the first plane and a position closer to the projector side from the first plane by a statistically determined thickness of the breast. The mammography apparatus according to claim 1.

4. The focus of the projection optical system is adjusted to the first plane. The mammography apparatus according to claim 3.

5. The second surface of the compression plate is subjected to a light transmission suppression treatment that suppresses the transmission of light to the region on which the second information is projected. The mammography apparatus according to claim 1.

6. The first piece of information is a skin line that indicates the contour of the breast, which serves as a guide when placing the breast. The mammography apparatus according to claim 1.

7. The second piece of information is the shooting conditions when photographing the breast, The mammography apparatus according to claim 1.

Images