IMAGE PROCESSING APPARATUS, RADIOLOGICAL IMAGE CAPTURE SYSTEM, IMAGE PROCESSING METHOD, AND IMAGE PROCESSING PROGRAM

Abstract

To provide an image processing device, a radiation ray image imaging system, an image processing method and an image processing program capable of accurately deriving a radiation position of radiation ray.SOLUTION: A CPU 50A acquires in a state in which, a marker 90i is arranged, a tomographic image 82t which is imaged for every radiation position 19t and a radiation position 19Vt which is set as each radiation position of a projection image 80t, then uses the set radiation position 19Vt for generating a tomographic image 82 from the projection image 80t, then derives a coordinate on a three dimensional position where the marker 90i is arranged from the tomographic image 82, and on the basis of the set radiation position 19 Vt and the three dimensional position coordinate of the marker 90i, derives a first two-dimensional coordinate of the marker 90i which is projected on the projection plane 80A, then, on the basis of a second two-dimensional coordinate of the marker 90i on the projection plane 80A derived from the marker image 91ti indicating the marker 90i included in each projection image 80t and the first two-dimensional coordinate, estimates a radiation position 19t.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present disclosure relates to an image processing device, a radiation image capturing system, an image processing method, and an image processing program. [Background technology]

[0002] 2. Description of the Related Art So-called tomosynthesis imaging is known in which a radiation source irradiates a subject from a plurality of irradiation positions each having a different irradiation angle, and a plurality of projection images of the subject are captured at the different irradiation positions.

[0003] There is a known technology for generating a tomographic image from a projection image using the position of a radiation source when the projection image is captured. For example, in a reconstruction processing method such as the FBP (Filter Back Projection) method and the iterative approximation reconstruction method, which are known as methods for generating tomographic images, a tomographic image is generated based on the position of a radiation source in a three-dimensional space and the two-dimensional position of each pixel of the projection image. Therefore, if the position of the radiation source is inaccurate, the accuracy of the tomographic image generated using the inaccurate radiation source position may be reduced.

[0004] Therefore, there are known techniques for obtaining an accurate radiation source position. For example, Patent Document 1 describes a technique for calibrating the position of a radiation source based on the relative relationship between the positions of marker images included in multiple projection images obtained by photographing a marker. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-13651 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the conventional technology, when deriving the irradiation position where the radiation source is located using a projection image obtained by capturing a marker, the accuracy of deriving the irradiation position may decrease.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide an image processing device, a radiographic image capturing system, an image processing method, and an image processing program that are capable of accurately deriving the radiation irradiation position. [Means for solving the problem]

[0008] In order to achieve the above object, an image processing device according to a first aspect of the present disclosure is an image processing device that processes a plurality of projection images obtained by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles, and includes at least one processor, wherein the processor acquires a plurality of projection images taken for each irradiation position and a plurality of setting irradiation positions set as the respective irradiation positions of the plurality of projection images with a marker disposed between the plurality of irradiation positions and a projection surface, generates a first tomographic image from the plurality of projection images using the plurality of setting irradiation positions, derives a first three-dimensional position at which the marker is disposed from the first tomographic image, derives a first projection surface position of the marker projected onto the projection surface from the plurality of setting irradiation positions and the first three-dimensional position of the marker, and estimates the plurality of irradiation positions based on a second projection surface position of the marker on the projection surface derived from a marker image representing the marker included in each of the plurality of projection images and the first projection surface position. The subject is a breast compressed by a compression member, and the markers are provided on the compression member. .

[0009] An image processing device according to a second aspect of the present disclosure is the image processing device according to the first aspect, wherein the processor estimates a plurality of illumination positions where a plurality of first projection surface positions coincide with a plurality of second projection surface positions.

[0010] An image processing device of a third aspect of the present disclosure is an image processing device of the first or second aspect, in which the processor further estimates a second three-dimensional position of the marker based on a plurality of first projection surface positions and a plurality of second projection surface positions.

[0011] An image processing device of a fourth aspect of the present disclosure is an image processing device of any one of the first to third aspects, in which a processor generates a second tomographic image from a plurality of projection images using a plurality of estimated irradiation positions.

[0012] A fifth aspect of the image processing device of the present disclosure is the image processing device of the third aspect, in which a processor generates a second tomographic image from a plurality of projection images using a plurality of estimated irradiation positions, up to a height corresponding to a height direction position at a second three-dimensional position.

[0013] An image processing device according to a sixth aspect of the present disclosure is the image processing device according to the third or fifth aspect, further comprising: , No. Based on the three-dimensional position of 2, the thickness of the compressed breast may be estimated.

[0014] An image processing device according to a seventh aspect of the present disclosure is the image processing device according to the sixth aspect, wherein the processor derives information relating to the glandular volume of the breast based on the thickness.

[0015] An image processing device according to an eighth aspect of the present disclosure is the image processing device according to the sixth aspect, wherein the processor estimates the amount of scattered radiation based on the thickness.

[0016] An image processing device of a ninth aspect of the present disclosure is an image processing device of any one of the first to eighth aspects, in which multiple markers are arranged between multiple irradiation positions and a projection surface.

[0017] An image processing device of a tenth aspect of the present disclosure is an image processing device of any one of the first to ninth aspects, in which a processor estimates a plurality of illumination positions where a plurality of first projection surface positions coincide with a second projection surface position by repeatedly updating a plurality of set illumination positions and a first three-dimensional position to repeatedly derive a first projection surface position.

[0018] An image processing device of an eleventh aspect of the present disclosure is the image processing device of the tenth aspect, in which the markers are arranged according to predetermined placement conditions, and the processor updates the first three-dimensional position within the range of the placement conditions.

[0019] In order to achieve the above object, a radiographic imaging system according to a twelfth aspect of the present disclosure includes a radiation source that generates radiation, a radiographic imaging device that performs tomosynthesis imaging in which radiation is irradiated from the radiation source toward a subject from each of a plurality of irradiation positions having different irradiation angles, and a projection image of the subject is captured for each irradiation position, and an image processing device according to the present disclosure.

[0020] In order to achieve the above object, an image processing method according to a thirteenth aspect of the present disclosure is an image processing method for processing a plurality of projection images obtained by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles, the method comprising the steps of: acquiring a plurality of projection images taken for each irradiation position and a plurality of set irradiation positions set as the respective irradiation positions of the plurality of projection images, with a marker disposed between the plurality of irradiation positions and a projection surface; generating a first tomographic image from the plurality of projection images using the plurality of set irradiation positions; deriving a first three-dimensional position at which the marker is disposed from the first tomographic image; deriving a first projection surface position of the marker projected onto the projection surface from the plurality of set irradiation positions and the first three-dimensional position of the marker; and estimating the plurality of irradiation positions based on a second projection surface position of the marker on the projection surface derived from a marker image representing the marker included in each of the plurality of projection images and the first projection surface position. The subject is a breast compressed by a compression member, and the markers are provided on the compression member. This is an image processing method in which the processing is carried out by a computer.

[0021] In order to achieve the above object, an image processing program according to a fourteenth aspect of the present disclosure is an image processing program for processing a plurality of projection images obtained by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles, the image processing program acquiring a plurality of projection images taken for each irradiation position and a plurality of set irradiation positions set as the respective irradiation positions of the plurality of projection images with a marker disposed between the plurality of irradiation positions and a projection surface, generating a first tomographic image from the plurality of projection images using the plurality of set irradiation positions, deriving a first three-dimensional position at which the marker is disposed from the first tomographic image, deriving a first projection surface position of the marker projected onto the projection surface from the plurality of set irradiation positions and the first three-dimensional position of the marker, and estimating the plurality of irradiation positions based on a second projection surface position of the marker on the projection surface derived from a marker image representing the marker included in each of the plurality of projection images and the first projection surface position. The subject is a breast compressed by a compression member, and the markers are provided on the compression member. It is for causing a computer to execute the process. Effect of the Invention

[0022] According to the present disclosure, the radiation irradiation position can be derived with high accuracy. [Brief description of the drawings]

[0023] [Figure 1] 1 is a configuration diagram illustrating an example of the overall configuration of a radiation image capturing system according to an embodiment; [Diagram 2] FIG. 13 is a diagram for explaining a plurality of markers provided on the compression plate. [Diagram 3] FIG. 1 is a diagram for explaining an example of tomosynthesis imaging. [Figure 4] 1 is a block diagram showing an example of the configuration of a mammography apparatus and a console according to an embodiment. [Diagram 5] FIG. 2 is a functional block diagram illustrating an example of functions of a console according to an embodiment. [Figure 6] FIG. 2 is a diagram for explaining functions of a console. [Figure 7]11 is a diagram for explaining derivation of a projection surface position of a marker on a projection surface. FIG. [Figure 8] 10 is a flowchart illustrating an example of a flow of image processing by the console of the embodiment. [Figure 9] 11 is a flowchart illustrating an example of the flow of an estimation process in image processing. [Figure 10] 11 is a flowchart showing an example of the flow of a tomographic image generating process in image processing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment.

[0025] First, an example of the overall configuration of the radiation image capturing system of this embodiment will be described. Fig. 1 shows a configuration diagram showing an example of the overall configuration of the radiation image capturing system 1 of this embodiment. As shown in Fig. 1, the radiation image capturing system 1 of this embodiment includes a mammography device 10 and a console 12.

[0026] First, the mammography device 10 of this embodiment will be described. Fig. 1 shows a side view illustrating an example of the appearance of the mammography device 10 of this embodiment. Fig. 1 shows an example of the appearance of the mammography device 10 when viewed from the left side of a subject.

[0027] The mammography device 10 of this embodiment operates under the control of a console 12, and is a device that takes a radiographic image of a subject's breast by irradiating the breast with radiation R (e.g., X-rays) as a subject's subject. Note that the mammography device 10 may be a device that takes an image of the subject's breast not only when the subject is standing (standing position) but also when the subject is sitting in a chair (including a wheelchair) or the like (seated position).

[0028] In addition, the mammography apparatus 10 of this embodiment has the function of performing normal imaging, in which imaging is performed with the radiation source 29 positioned at an irradiation position along the normal direction of the detection surface 20A of the radiation detector 20, and so-called tomosynthesis imaging, in which imaging is performed by moving the radiation source 29 to each of a number of irradiation positions.

[0029] The radiation detector 20 detects radiation R that has passed through the breast, which is the subject. In detail, the radiation detector 20 detects radiation R that has entered the subject's breast and the imaging table 24 and reached the detection surface 20A of the radiation detector 20, generates a radiographic image based on the detected radiation R, and outputs image data representing the generated radiographic image. Hereinafter, a series of operations of irradiating radiation R from the radiation source 29 and generating a radiographic image by the radiation detector 20 may be referred to as "imaging". On the detection surface 20A of the radiation detector 20 of this embodiment, a plurality of pixels corresponding to the radiographic image generated by the radiation detector 20 are arranged in a matrix. The type of the radiation detector 20 of this embodiment is not particularly limited, and may be, for example, an indirect conversion type radiation detector that converts radiation R into light and converts the converted light into an electric charge, or a direct conversion type radiation detector that directly converts radiation R into an electric charge.

[0030] 1, the radiation detector 20 is disposed inside an imaging stand 24. In the mammography apparatus 10 of this embodiment, when imaging is performed, the breast of the subject is positioned on the imaging surface 24A of the imaging stand 24 by the user.

[0031] The compression plate 38 used to compress the breast when imaging is performed is attached to a compression unit 36 ​​provided on the imaging table 24. In detail, the compression unit 36 ​​is provided with a compression plate drive section (not shown) that moves the compression plate 38 in a direction toward or away from the imaging table 24 (hereinafter referred to as the "up and down direction"). A support section 39 of the compression plate 38 is detachably attached to the compression plate drive section and is moved in the up and down direction by the compression plate drive section to compress the breast of the subject between the compression plate 38 and the imaging table 24. The compression plate 38 of this embodiment is an example of a compression member of the present disclosure.

[0032] As shown in Fig. 1 and Fig. 2, the compression plate 38 of this embodiment includes a compression portion 38A that contacts and compresses the breast. A plurality of markers 90 are provided on an upper surface 38AA of the compression portion 38A, which is opposite to the compression surface that contacts the breast. i (i=1, 2, . . . , the maximum value is 12 in FIG. 3) are spaced apart in the X direction by L1 and spaced apart in the Y direction by L2. i 19 is the irradiation position for tomosynthesis imaging. t It is used to estimate marker 90 i Irradiation position 19 using t The estimation of marker 90 will be described in detail later. i The marker 90 is made of a material that is visible in the radiation image. i The material for the compression plate 38 is preferably a material that absorbs radiation R. Examples of materials that absorb radiation R include metals such as lead, and UV (UltraViolet) absorbing glass. In order to make it easier for the user to check the shape and position of the breast in a compressed state when compressing and positioning the breast with the compression plate 38, it is preferable that the compression portion 38A of the compression plate 38 is transparent. For this reason, the marker 90 i It is preferable that the cover is transparent, and that a transparent material such as UV-cut glass is used.

[0033] In addition, marker 90 i The positions where the markers 90 are provided and the number of markers 90 provided are not limited to those in this embodiment. i The position where the projection image is taken is set to the projection position 19. t The marker 90 may be located between the projection surface 80A of the projection image and the detection surface 20A of the radiation detector 20. i The number of irradiation positions is, for example, 19. t The estimation accuracy of marker 90 i The number of markers 90 may be determined according to the size of the area where the markers 90 are provided (in FIG. 2, the size of the upper surface 38AA). i The coordinates of the corresponding positions are written as marker 90 in the code representing each image. i The symbol "i" is added to indicate this.

[0034] As shown in Fig. 1, the mammography apparatus 10 of this embodiment includes an imaging table 24, an arm unit 33, a base 34, and an axis unit 35. The arm unit 33 is held by the base 34 so as to be movable in the vertical direction (Z-axis direction). The axis unit 35 enables the arm unit 33 to rotate relative to the base 34. The axis unit 35 is fixed to the base 34, and the axis unit 35 and the arm unit 33 rotate together.

[0035] Gears are provided on the shaft 35 and the compression unit 36 ​​of the imaging table 24, and by switching between an engaged state and a non-engaged state of these gears, it is possible to switch between a state in which the compression unit 36 ​​of the imaging table 24 and the shaft 35 are connected and rotate together, and a state in which the shaft 35 is separated from the imaging table 24 and rotates freely. Note that the switching between transmission and non-transmission of power to the shaft 35 is not limited to the above gears, and various mechanical elements can be used.

[0036] The arm unit 33 and the imaging stand 24 are separately rotatable relative to the base 34, with the shaft unit 35 as a rotation axis. In this embodiment, the base 34, the arm unit 33, and the compression unit 36 ​​of the imaging stand 24 are each provided with an engagement unit (not shown), and by switching the state of this engagement unit, each of the arm unit 33 and the compression unit 36 ​​of the imaging stand 24 is connected to the base 34. One or both of the arm unit 33 and the imaging stand 24 connected to the shaft unit 35 rotate together around the shaft unit 35.

[0037] When performing tomosynthesis imaging in the mammography apparatus 10, the radiation source 29 of the radiation irradiation unit 28 is moved sequentially to each of a plurality of irradiation positions with different irradiation angles by the rotation of the arm unit 33. The radiation source 29 has a radiation tube (not shown) that generates radiation R, and the radiation tube is moved to each of the plurality of irradiation positions in accordance with the movement of the radiation source 29. FIG. 3 is a diagram for explaining an example of tomosynthesis imaging. Note that the compression plate 38 is not shown in FIG. 3. In this embodiment, as shown in FIG. 3, the radiation source 29 is moved sequentially to each of the irradiation positions 19 with irradiation angles that differ in increments of a predetermined angle β. t (t=1, 2, . . . , the maximum value is 7 in FIG. 3), in other words, the radiation detector 20 is moved to a position where the irradiation angle of the radiation R with respect to the detection surface 20A of the radiation detector 20 is different. t In response to an instruction from the console 12, radiation R is irradiated from the radiation source 29 toward the subject U, and a radiation image is captured by the radiation detector 20. t 19 to each of the irradiation positions 19 t In the case of tomosynthesis imaging, in which radiation images are captured at irradiation positions 191 to 197, seven radiation images are obtained in the example of Fig. 3. In this embodiment, as shown in Fig. 3, a case in which seven projection images are obtained at irradiation positions 191 to 197 in tomosynthesis imaging will be described as an example. Note that in this embodiment, in tomosynthesis imaging, t When a radiation image captured at each irradiation position 19 is to be described as being different from other radiation images, it is called a "projection image." When a radiation image is to be generally referred to regardless of the type of projection image or tomographic image (to be described later), it is simply called a "radiation image." t When collectively referring to the irradiation positions, the symbol t for distinguishing each irradiation position is omitted and they are referred to as "irradiation positions 19". t Projection images taken at 19 irradiation positions t For the corresponding images, the symbols representing each image are indicated with the irradiation position 19. t The symbol "t" is added to indicate this.

[0038] In this embodiment, the irradiation position 19V t However, these are preset as irradiation positions in tomosynthesis imaging used when a second tomographic image generating unit, the details of which will be described later, generates a tomographic image 80 (see FIG. 8). t However, the actual position of the radiation source 29 when the projection image 80 is captured in the tomosynthesis imaging is the irradiation position 19. t The irradiation position of the setting 19V may change depending on the time of use. t Therefore, the console 12 of the present embodiment is configured to set the irradiation position 19V t The actual irradiation position is 19. t By updating to 19, the actual irradiation position t This will be described in detail later.

[0039] In addition, the irradiation position 19, which is the actual position of the radiation source 29 when the projection image 80 is captured in the tomosynthesis imaging, t The irradiation position of the setting 19V may change depending on the time of use. t The irradiation position in the setting may be different from 19V. t The set irradiation position 19V is an irradiation position that is set as an irradiation position used when a second tomographic image generating unit, the details of which will be described later, generates a tomographic image 80 (see FIG. 8). t For example, the designed irradiation position is an example. t And the setting irradiation position is 19V t Therefore, the console 12 of this embodiment is configured to detect the actual irradiation position 19 t This will be described in detail later.

[0040] 3, the irradiation angle of radiation R refers to the angle α between a normal CL to the detection surface 20A of the radiation detector 20 and a radiation axis RC. The radiation axis RC refers to an axis connecting the focal point of the radiation source 29 at each irradiation position 19 and a preset position such as the center of the detection surface 20A. Here, the detection surface 20A of the radiation detector 20 is a surface that is approximately parallel to the imaging surface 24A.

[0041] On the other hand, when performing normal imaging in the mammography device 10, the radiation source 29 of the radiation irradiation unit 28 is positioned at the irradiation position 19 where the irradiation angle α is 0 degrees. t (Irradiation position along the normal direction 19 t 3), the radiation source 29 irradiates radiation R, and the radiation detector 20 captures a radiation image.

[0042] Moreover, Fig. 4 shows a block diagram showing an example of the configuration of the mammography apparatus and console of the embodiment. As shown in Fig. 4, the mammography apparatus 10 of the present embodiment further includes a control unit 40, a memory unit 42, an I / F (Interface) unit 44, an operation unit 46, and a radiation source movement unit 47. The control unit 40, the memory unit 42, the I / F unit 44, the operation unit 46, and the radiation source movement unit 47 are connected via a bus 49 such as a system bus or a control bus so that various information can be exchanged between them.

[0043] The control unit 40 controls the overall operation of the mammography apparatus 10 in response to control by the console 12. The control unit 40 includes a CPU (Central Processing Unit) 40A, a ROM (Read Only Memory) 40B, and a RAM (Random Access Memory) 40C. The ROM 40B stores various programs in advance, including an imaging program 41 for controlling radiographic imaging, which is executed by the CPU 40A. The RAM 40C temporarily stores various data.

[0044] The storage unit 42 stores image data of a radiation image captured by the radiation detector 20 and various other information. Specific examples of the storage unit 42 include a hard disk drive (HDD) and a solid state drive (SSD). The I / F unit 44 communicates various information with the console 12 by wireless communication or wired communication. Image data of a radiation image captured by the radiation detector 20 in the mammography apparatus 10 is transmitted to the console 12 via the I / F unit 44 by wireless communication or wired communication.

[0045] In this embodiment, the control unit 40 , the storage unit 42 , and the I / F unit 44 are each provided inside the imaging stand 24 .

[0046] The operation unit 46 is provided as a plurality of switches on, for example, the imaging table 24 of the mammography apparatus 10. The operation unit 46 may be provided as a touch panel switch, or as a foot switch that is operated by a user such as a doctor or technician with his / her foot.

[0047] As described above, when tomosynthesis imaging is performed, the radiation source moving unit 47 has a function of moving the radiation source 29 to each of the multiple irradiation positions 19 under the control of the control unit 40. Specifically, the radiation source moving unit 47 moves the radiation source 29 to each of the multiple irradiation positions 19 by rotating the arm unit 33 relative to the imaging table 24. The radiation source moving unit 47 in this embodiment is provided inside the arm unit 33.

[0048] On the other hand, the console 12 in this embodiment has the function of controlling the mammography apparatus 10 using shooting orders and various information obtained from a RIS (Radiology Information System) or the like via a wireless communication LAN (Local Area Network) or the like, and instructions given by a user via an operation unit 56 or the like.

[0049] The console 12 of the present embodiment is, for example, a server computer. As shown in Fig. 4, the console 12 includes a control unit 50, a storage unit 52, an I / F unit 54, an operation unit 56, and a display unit 58. The control unit 50, the storage unit 52, the I / F unit 54, the operation unit 56, and the display unit 58 are connected to each other via a bus 59 such as a system bus or a control bus so as to be able to transmit and receive various information to and from each other.

[0050] The control unit 50 of this embodiment controls the overall operation of the console 12. The control unit 50 includes a CPU 50A, a ROM 50B, and a RAM 50C. The ROM 50B stores various programs including an image generation program 51 executed by the CPU 50A in advance. The RAM 50C temporarily stores various data. In this embodiment, the CPU 50A is an example of a processor of the present disclosure, and the console 12 is an example of an image processing device of the present disclosure. Moreover, the image generation program 51 of this embodiment is an example of an image processing program of the present disclosure.

[0051] The storage unit 52 stores image data of radiographic images captured by the mammography apparatus 10, various other information, etc. Specific examples of the storage unit 52 include an HDD and an SSD.

[0052] The operation unit 56 is used by the user to input instructions regarding radiographic image capture, including instructions for irradiating radiation R, and various types of information. The operation unit 56 is not particularly limited, and examples thereof include various switches, a touch panel, a touch pen, and a mouse. The display unit 58 displays various types of information. The operation unit 56 and the display unit 58 may be integrated into a touch panel display.

[0053] The I / F unit 54 communicates various types of information with the mammography apparatus 10, the RIS, and a PACS (Picture Archiving and Communication System) via wireless or wired communication. In the radiation image capturing system 1 of this embodiment, image data of a radiation image captured by the mammography apparatus 10 is received by the console 12 from the mammography apparatus 10 via the I / F unit 54 via wireless or wired communication.

[0054] The console 12 of this embodiment is a device for projecting a plurality of projection images in a tomosynthesis imaging. t FIG. 5 shows an actual projection position 19 when a plurality of projection images are projected in tomosynthesis imaging in the console 12 of this embodiment. t 5 shows a functional block diagram of an example of a configuration related to a function of estimating the position of the projection plane. As shown in FIG. 5, the console 12 includes an acquisition unit 60, a first tomographic image generation unit 62, a first three-dimensional position derivation unit 64, a first projection plane position derivation unit 66, a second projection plane position derivation unit 68, an estimation unit 70, a second tomographic image generation unit 74, and a display control unit 76. As an example, the console 12 of this embodiment is configured such that the CPU 50A of the control unit 50 executes the image generation program 51 stored in the ROM 50B, so that the CPU 50A functions as the acquisition unit 60, the first tomographic image generation unit 62, the first three-dimensional position derivation unit 64, the first projection plane position derivation unit 66, the second projection plane position derivation unit 68, the estimation unit 70, the second tomographic image generation unit 74, and the display control unit 76. The functions of each unit will be described with reference to FIG. 6 and FIG. 7.

[0055] The acquisition unit 60 includes a first acquisition unit 60A and a second acquisition unit 60B. The first acquisition unit 60A acquires a marker 90 i Multiple projected images with t The first acquisition unit 60A of this embodiment acquires image data representing projection images 801 to 807 (see FIG. 6) acquired by tomosynthesis imaging in the mammography apparatus 10. The projection images 80 acquired by the first acquisition unit 60A t Each of the markers has ai Marker image 92 representing ti In this embodiment, as shown in FIG. 6, the projection image 801 includes a marker image 92. 1i The projection image 802 includes a marker image 92 2i The projection image 803 includes the marker image 92 3i The projection image 807 also includes a marker image 92. 7i The first acquisition unit 60A outputs image data representing the acquired projection images 801 to 807 to the first tomographic image generation unit 62, the first projection plane position derivation unit 66, and the second projection plane position derivation unit 68.

[0056] The second acquisition unit 60B acquires the plurality of projection images 80 acquired by the first acquisition unit 60A. t Each of the irradiation positions was set as a multiple setting of irradiation position 19V t The second acquisition unit 60B of the present embodiment has a function of acquiring the irradiation position 19V t As the irradiation position 19V in the three-dimensional space setting t Coordinates (sx t , sy t , sz t The second acquisition unit 60B acquires the irradiation position 19V t There is no particular limitation on the method of acquiring the above. For example, the second acquisition unit 60B acquires the above-mentioned irradiation position 19V from the mammography device 10. t For example, the projection image may be provided with information indicating the irradiation position 19V on the setting as shooting information. t When the information representing the projection position is attached, the projection position 19V in the setting is determined from the shooting information attached to the acquired projection image. t The second acquisition unit 60B may acquire information representing the irradiation positions 19V on the acquired settings. t Coordinates (sx t , sy t , sz t ), and outputs it to the first tomographic image generating unit 62 and the first projection plane position deriving unit 66.

[0057] The first tomographic image generating unit 62 detects a plurality of irradiation positions 19Vt Using multiple projection images 80 t Tomographic image 82 k As shown in FIG. 6, the first tomographic image generating unit 62 of this embodiment has a function of generating a tomographic image at a preset irradiation position 19V t Using the above, k slice images 821-82 are generated from the projection images 801-807. k In the following, the tomographic images 821 to 82 k When they are collectively referred to without distinguishing between them, they are referred to as "tomographic image 82". The tomographic image 82 of this embodiment is an example of a first tomographic image of the present disclosure. The method by which the first tomographic image generating unit 62 generates the tomographic image 82 is not particularly limited, and a known method can be used. For example, reconstruction may be performed by a back projection method such as the FBP (Filter Back Projection) method or the iterative reconstruction method, and known techniques can be applied. Note that the tomographic plane of the tomographic image 82 generated by the first tomographic image generating unit 62 is a plane approximately parallel to the detection surface 20A of the radiation detector 20, and in this embodiment, is a plane approximately parallel to the imaging surface 24A of the imaging table 24. The position of the tomographic plane of the tomographic image 82 generated by the first tomographic image generating unit 62, in other words, the height of the tomographic plane from the imaging surface 24A of the imaging table 24 is not particularly limited. The height of the slice plane can be determined according to, for example, the size of the object of interest, the image quality of the radiation image, the processing load of the calculation process in generating the slice image, and instructions from the user.

[0058] Tomographic images 821-82 k Of these, 90 are markers. i Marker image 94 i Marker 90 i The marker 90 is included in the tomographic image 82 according to the height at which the marker 90 exists, i.e., the position in the Z-axis direction. i is provided on the upper surface 38AA of the compression portion 38A of the compression plate 38. i is included in the tomographic image 82 corresponding to the height of the upper surface 38AA. In the example shown in FIG. 6, the marker image 94 is included in the tomographic image 821 at the highest position, in other words, at the position closest to the radiation source 29. i The tomographic images are included. idoes not include an image showing the breast, which is the subject U. On the other hand, the cross-sectional images 822 to 82 k corresponds to the area below the compression plate 38, so the marker image 94 i , and includes an image of a subject U, which is a breast.

[0059] The first tomographic image generating unit 62 outputs image data representing the generated k tomographic images 82 to the first three-dimensional position deriving unit 64.

[0060] The first three-dimensional position deriving unit 64 derives the marker 90 from the tomographic image 82. i The first three-dimensional position derivation unit 64 of the present embodiment derives the three-dimensional position at which the marker 90 is arranged. i Marker 90 as the position i Coordinates in the three-dimensional space (mx i ,my i ,mz i The first three-dimensional position deriving unit 64 derives the coordinates (mx i ,my i ,mz i The method of deriving the three-dimensional position 82 is not particularly limited. As an example, in the present embodiment, the XY coordinate values ​​are determined in advance for each pixel of the tomographic image 82, and the Z coordinate value is determined in advance according to the height of the tomographic image 82. The first three-dimensional position deriving unit 64 derives the three-dimensional position 821 to 82 k Of these, 94 are marker images. i A tomographic image 821 including the marker images 94 included in the tomographic image 821 is extracted. i The position of each marker image 94 i The first three-dimensional position derivation unit 64 identifies the center of gravity of each marker image 94. i The XY coordinate values ​​of the pixel corresponding to the center of gravity of each marker 90 and the Z coordinate value associated with the tomographic image 821 are used to calculate the position of each marker 90. i The position of the coordinates (mx i ,my i ,mz i ) is derived.

[0061] The first three-dimensional position deriving unit 64 derives each marker image 94 included in the tomographic image 821. i The method of detecting the position of the marker image 94 is not particularly limited. For example, the marker image 94 may be detected by template matching. i Alternatively, for example, a method for detecting a known marker image 94 may be applied. i The marker image 94 is used as training data. i A method using a trained model consisting of a neural network that has undergone deep learning may be applied so that the trained model can detect the above-mentioned. In addition to the deep learning neural network, the trained model may be, for example, a support vector machine (SVM), a convolutional neural network (CNN), a recurrent neural network (RNN), or the like.

[0062] Also, in the tomographic image 821, each marker 90 i Marker image 94 corresponding to i The region in which the marker image 94i is included is determined in advance. Therefore, the first three-dimensional position deriving unit 64 derives each marker image 94 included in the tomographic image 821 in the region determined in advance as including the marker image 94i. i In this case, the position of the marker image 94 may be detected. i This reduces the processing load required for the detection and shortens the processing time.

[0063] In addition, the irradiation position 19V in the setting used to generate the tomographic image 82 t As mentioned above, the actual irradiation position in tomosynthesis imaging is t This may differ from the setting. t and irradiation position 19 t are different, the marker 90 derived by the first three-dimensional position derivation unit 64 i The coordinates (mx i ,my i ,mzi ) also marker 90 i is different from the actual location.

[0064] The first three-dimensional position derivation unit 64 determines the position of each derived marker 90 i Position coordinates (mx i ,my i ,mz i ) to the first projection plane position derivation unit 66.

[0065] The first projection plane position deriving unit 66 is a projection position 19V t and marker 90 i From the position of the marker 90 projected on the projection surface 80A, i The first projection plane position derivation unit 66 has a function of deriving the projection plane position of the marker 90. i The projection surface position is the irradiation position 19V in the setting. t The radiation source 29 emits radiation R to generate a projection image 80. t When the image is captured, the captured projection image 80 t 90 markers included i Marker image 92 representing ti The first projection plane position derivation unit 66 calculates the marker image 92 in this case. ti The position of is derived as the projection surface position.

[0066] Referring to FIG. 7, the marker 90 by the first projection plane position deriving unit 66 of this embodiment i A method for deriving the projection plane position of each of the projection positions 19 will be described below. t 80 corresponding projection images t The area of ​​the projection surface 80A corresponding to t and the projection surface is 80A. t Marker 90 in i The position of the marker image 91 ti is shown as:

[0067] As shown in Figure 7, the irradiation position 19V on each setting t The coordinates of the position are (sx t ,sy t ,sz t) and the marker 90 on the projection plane 80A i Marker image 91 showing the position of ti The coordinates of (px' ti ,py' ti ) coordinate px' ti The value of , is expressed by the following formula (1). Also, the coordinate py' ti The value is expressed by the following formula (2).

[0068]

number

[0069] The first projection plane position deriving unit 66 is a projection position 19V t Coordinates (sx t ,sy t ,sz t ) and marker 90 i Coordinates (mx i ,my i ,mz i ) and the marker image 91 is calculated by the above equations (1) and (2). ti Coordinates (px' ti ,py' ti ) to marker 90 i The projection position on the projection surface 80A is derived as the projection surface position of the projection position 19. t Every 91 marker images ti Coordinates (px' ti ,py' ti For example, as shown in FIG. 6, the first projection plane position derivation unit 66 derives the marker image 91 on the projection plane 80A1 corresponding to the irradiation position 191. 1i Coordinates (px' 1i ,py' 1i ), the marker image 91 on the projection plane 80A2 corresponding to the irradiation position 192 2i Coordinates (px' 2i ,py' 2i ), and the marker image 91 on the projection plane 80A3 corresponding to the irradiation position 193 3i Coordinates (px' 3i ,py' 3iThe first projection plane position deriving unit 66 also derives the marker image 91 on the projection plane 80A7 corresponding to the irradiation position 191. 7i Coordinates (px' 7i ,py' 7i ) is derived. Below, the coordinates (px' ti ,py' ti ) to "Marker 90 i The first two-dimensional coordinates of the marker 90 derived by the first projection plane position derivation unit 66 of this embodiment are referred to as the "first two-dimensional coordinates of the marker 90." i The first two-dimensional coordinate (px' ti ,py' ti ) is an example of a first projection plane position of the present disclosure.

[0070] The first projection plane position derivation unit 66 determines the derived marker 90 i The first two-dimensional coordinate (px' ti ,py' ti ) to the estimation unit 70.

[0071] The second projection plane position deriving unit 68 detects the projection image 80 t Each of the markers 90 i Marker image 92 representing ti From the marker 90 on the projection plane 80A i The second projection plane position derivation unit 68 of the present embodiment has a function of deriving the position of the marker 90 on the projection plane 80A. i As the position of the projection image 80 t 92 marker images included ti Position coordinates (px ti ,py ti ) is derived. Below, the coordinates (px ti ,py ti ) to "Marker 90 i The marker 90 derived by the second projection plane position derivation unit 68 of this embodiment is called the "second two-dimensional coordinates of the marker 90." i The second two-dimensional coordinate (px ti ,py ti ) is an example of the second projection plane position of the present disclosure.

[0072] The second projection plane position deriving unit 68 detects the projection image 80 t 92 marker images includedti From marker 90 i The second two-dimensional coordinate (px ti ,py ti There is no particular limitation on the method for deriving the projection image 80 in this embodiment. t The XY coordinate values ​​are determined in advance for each pixel of the projection image 80. t Each marker image 92 ti The position of each marker image 92 ti The second projection plane position deriving unit 68 determines the center of gravity of each marker image 92. ti From the XY coordinate values ​​of the pixel corresponding to the center of gravity of the marker 90 i The second two-dimensional coordinate (px ti ,py ti ) is derived.

[0073] The second projection plane position deriving unit 68 derives the derived marker 90 i The second two-dimensional coordinate (px ti ,py ti ) to the estimation unit 70.

[0074] The estimation unit 70 detects the marker 90 i The first two-dimensional coordinate (px' ti ,py' ti ) and 90 i The second two-dimensional coordinate (px ti ,py ti ) based on the above, the actual irradiation position in tomosynthesis imaging is irradiation position 19 t As shown in FIG.

[0075] Marker 90 i The first two-dimensional coordinate (px' ti ,py' ti ) is a marker 90 derived from a tomographic image 82 i 3D position and the irradiation position 19V in the setting t This is a so-called marker 90 derived from i On the other hand, the marker 90 i The second two-dimensional coordinate (pxti ,py ti ) for each projection image 80 t Derived from, so to speak, marker 90 i The estimation unit 70 estimates the actual two-dimensional position of the marker 90, which is a hypothetical two-dimensional position. i The first two-dimensional coordinate (px' ti ,py' ti ) to the marker 90, which is the actual two-dimensional position. i The second two-dimensional coordinate (px ti ,py ti ) to the actual irradiation position in tomosynthesis imaging. t Estimate.

[0076] Setting irradiation position 19V t Coordinates (sx t , sy t , sz t ) but the actual irradiation position 19 t The closer to the hypothetical 2D position of the marker 90 i The first two-dimensional coordinate (px' ti ,py' ti ) and the actual two-dimensional position of marker 90 i The second two-dimensional coordinate (px ti ,py ti ) (hereinafter, "Marker 90 i The difference between the two-dimensional positions of the markers (called the "difference in the two-dimensional position of the markers") becomes smaller. i The coordinates (mx i ,my i ,mz i ) is marker 90 i The closer to the actual location of the marker, the i The difference in two-dimensional position becomes smaller.

[0077] As an example, in this embodiment, the second two-dimensional coordinate (px ti ,py ti ) and the first two-dimensional coordinate (px' ti ,py' ti The square error between the target position and the target position is defined as the energy function E expressed by the following equation (3). The energy function E shown in equation (3) ist Coordinates (sx t , sy t , sz t ) but the actual irradiation position 19 t The closer to marker 90, the smaller the energy function E becomes. i The coordinates (mx i ,my i ,mz i ) is marker 90 i It becomes smaller as it gets closer to its actual location.

number

[0078] In this embodiment, the irradiation position in the setting is 19V t Coordinates (sx t , sy t , sz t ) and Marker 90 i Coordinates (mx i ,my i ,mz i The estimation unit 70 determines the irradiation position 19V on the setting that minimizes the energy function E of the above formula (3) based on the above formulas (1) and (2). t Coordinates (sx t , sy t , sz t ) and Marker 90 i The coordinates (mx i ,my i ,mz i ) is derived. The second 2D coordinate (px ti ,py ti ) and the first two-dimensional coordinate (px' ti ,py' ti The smaller the difference between the second two-dimensional coordinates (px ti ,py ti ) and the first two-dimensional coordinate (px' ti ,py' ti ) coincides, the energy function E is "0". The irradiation position 19V on the setting that minimizes this energy function E t Coordinates (sx t , sy t, sz t ) is the actual irradiation position in tomosynthesis imaging19 t Equivalent to marker 90 i The coordinates (mx i ,my i ,mz i ) is marker 90 i corresponds to the actual 3D position of

[0079] Therefore, the estimation unit 70 updates the setting irradiation position 19V, which is a parameter of the energy function E, by the update unit 72. t Coordinates (sx t , sy t , sz t ) and Marker 90 i Coordinates (mx i ,my i ,mz i ) and iteratively derive the energy function E using the above equation (3).

[0080] The update unit 72 updates the irradiation position 19V t Coordinates (sx t , sy t , sz t ) and Marker 90 i Coordinates (mx i ,my i ,mz i As an example, the update unit 72 of the present embodiment has a function of updating each of the markers 90 i Within the range of the placement conditions of marker 90 i Coordinates (mx i ,my i ,mz i ) is updated. As mentioned above, marker 90 i The markers 90 are arranged on the upper surface 38AA of the compression part 38A of the compression plate 38 with an interval L1 in the X direction and an interval L2 in the Y direction. i is 90 degrees from the adjacent marker. i The markers are arranged under the conditions of intervals L1 and L2. i The positions of the markers 90 are restricted by the intervals L1 and L2.i Coordinates (mx i ,my i ,mz i ) can reduce the amount of processing required to minimize the energy function E. i The arrangement conditions of the marker 90 are not limited to the present embodiment. i The placement conditions include conditions according to the bending state of the compression portion 38A of the compression plate 38, the inclination state of the compression plate 38 attached to the compression unit 36, and the rotation state of the compression plate 38 attached to the compression unit 36.

[0081] In addition, as an example, the update unit 72 of the present embodiment updates the irradiation position 19V t The irradiation position on the setting is within the range of the placement conditions of 19V t Coordinates (sx t , sy t , sz t In this embodiment, the irradiation position 19V t The interval between the 19V and 20V is set as a placement condition. t In this embodiment, the update unit 72 updates the irradiation position 19V in the setting within the range of the arrangement conditions. t Coordinates (sx t , sy t , sz t ), the amount of processing required to minimize the energy function E can be reduced.

[0082] In this way, the estimation unit 70 minimizes the energy function E in the above equation (3) to estimate the actual irradiation position 19 in the tomosynthesis imaging. t Coordinates and marker 90 i The estimation unit 70 estimates the coordinates of the actual three-dimensional position of the estimated actual irradiation position 19 in the tomosynthesis imaging. t Coordinates and marker 90 i The coordinates of the actual three-dimensional position are output to the second tomographic image generating unit 74.

[0083] The second tomographic image generating unit 74 detects the irradiation position 19 estimated by the estimation unit 70. t Using the position of t The second tomographic image generating unit 74 has a function of generating a tomographic image from the markers 90 estimated by the estimation unit 70. The tomographic image generated by the second tomographic image generating unit 74 of this embodiment is an example of the second tomographic image of the present disclosure. The method by which the second tomographic image generating unit 74 generates a tomographic image is not particularly limited, and a known method can be used. For example, a method similar to the method by which the first tomographic image generating unit 62 generates the tomographic image 82 can be applied. Note that the second tomographic image generating unit 74 of this embodiment generates a tomographic image from the markers 90 estimated by the estimation unit 70. i That is, the second tomographic image generating unit 74 generates a tomographic image up to a height corresponding to the position in the height direction of the actual three-dimensional position of the marker 90. In other words, the second tomographic image generating unit 74 sets the highest position of the tomographic plane of the tomographic image to be generated, in other words, the height of the tomographic plane of the tomographic image closest to the radiation source 29, to the marker 90. i The height is determined according to the height at which the marker 90 is placed. i Since the marker 90 is disposed on the upper surface 38AA of the compression portion 38A of the compression plate 38, i If the height (position in the Z-axis direction) of the marker 90 is known, the thickness of the breast compressed by the compression paddle 38 can be known. i Based on the height of the marker 90, the thickness of the breast is derived, and a tomographic image is generated up to a height corresponding to the derived thickness of the breast. i This means that, for example, marker 90 i In comparison with the case where a tomographic image is generated up to the height of the marker 90, the number of tomographic images generated by the second tomographic image generating unit 74 can be reduced, and therefore the amount of processing required for generating the tomographic image can be reduced. i Therefore, when generating a composite 2D image from multiple generated tomographic images, the composite 2D image does not include an image representing the marker 90. iIn this way, the second tomographic image generating unit 74 may further generate a composite two-dimensional image from the generated tomographic images. The method by which the second tomographic image generating unit 74 generates the composite two-dimensional image is not particularly limited, and any known method such as the method described in U.S. Pat. No. 8,983,156 or the method described in Japanese Patent Application Laid-Open No. 2014-128716 may be used.

[0084] It is known that the thicker the breast, the more scattered radiation is generated. Therefore, the second tomographic image generating unit 74 of this embodiment estimates the amount of scattered radiation based on the breast thickness derived as described above. In addition, the second tomographic image generating unit 74 applies a constant frequency removal filter that removes low frequency components according to the estimated amount of scattered radiation to the projection image 80. t Apply to projected image 80 t The second tomographic image generating unit 74 removes the scattered radiation component from the projection image 80 from which the scattered radiation has been removed. t By obtaining a correspondence relationship between the breast thickness and the low-frequency component removal filter to be applied to remove scattered radiation, the second tomographic image generating unit 74 can select the low-frequency component removal filter to be applied to remove scattered radiation from the derived breast thickness without estimating the amount of scattered radiation according to the breast thickness.

[0085] In addition, the second tomographic image generating unit 74 of this embodiment generates a projection image 80 tBased on the tomographic image generated from the above, information on the amount of mammary glands in the breast, which is the subject U, is derived. As an example, the second tomographic image generating unit 74 of the present embodiment derives the mammary gland content rate, which represents the content rate of mammary glands in the thickness direction of the breast, which is the irradiation direction of the radiation R, for each pixel as information on the amount of mammary glands. When there is no mammary gland and the breast is made of only fat, the mammary gland content rate is "0", and the higher the mammary gland density value, the higher the mammary gland content rate. The method by which the second tomographic image generating unit 74 derives the mammary gland content rate is not particularly limited, and a publicly known method can be applied. For example, the second tomographic image generating unit 74 can derive the mammary gland content rate based on the pixel values ​​of the regions in which the subject is not captured in each tomographic image, so-called blank regions, the pixel values ​​of the pixels corresponding to fat, the pixel values ​​of the pixels from which the mammary gland content rate is derived, and the average attenuation coefficient ratio between the mammary glands and fat (average attenuation coefficient of mammary glands / average attenuation coefficient of fat).

[0086] When the mammary glands of the breast are highly dense, in the case of a so-called dense step breast, there is a concern that the mammary glands may hide objects of interest such as tumors, so the mammary gland volume or density of the breast is derived, and it is desirable to derive it with higher accuracy. As described above, the derivation of mammary gland density is related to the thickness of the breast. However, when compressing the breast with the compression plate 38, the compression plate 38 may bend or tilt, and the thickness of the breast may not be uniform. Therefore, in this embodiment, a plurality of markers 90 i on the upper surface 38AA of the compression section 38A of the compression plate 38, the second tomographic image generating section 74 can derive the thickness of the breast in a local area. Therefore, the second tomographic image generating section 74 of this embodiment can derive the mammary gland volume with higher accuracy.

[0087] Each marker image 94 included in the tomographic image 821 i Each marker image 94 included in the position tomographic image 821 iThe second tomographic image generating unit 74 may derive a breast category according to the gland content rate, such as the above-mentioned dense breast, as information on the amount of glands. Examples of breast categories include the classification of "fatty", "scattered glands", "heterogeneous high density", and "(very) high density" shown in the mammography guidelines.

[0088] The second tomographic image generating unit 74 may derive other information from the thickness of the breast. For example, there is a corresponding relationship between the thickness of the breast and the radiation hardening of the radiation R, and the thicker the breast, the harder the radiation is. Therefore, the second tomographic image generating unit 74 may derive the degree of radiation hardening from the thickness of the breast.

[0089] The second tomographic image generating unit 74 outputs image data representing the generated tomographic image to the display control unit 76. In addition, the second tomographic image generating unit 74 outputs information related to the derived mammary gland volume to the display control unit 76.

[0090] The display control unit 76 has a function of causing the display unit 58 to display the tomographic images generated by the second tomographic image generating unit 74. The second tomographic image generating unit 74 also has a function of causing the display unit 58 to display information related to the mammary gland amount derived by the second tomographic image generating unit 74. The display destination of the tomographic images and the information related to the mammary gland amount is not limited to the display unit 58. For example, the display destination may be an external image reading device or the like of the radiation image capturing system 1. The display destination of the tomographic images and the information related to the mammary gland amount may be different.

[0091] Next, the operation of the console 12 in tomosynthesis imaging will be described with reference to the drawings. After tomosynthesis imaging is performed by the mammography apparatus 10, the console 12 generates a tomographic image using multiple projection images obtained by tomosynthesis imaging, and displays the image on the display unit 58 or the like.

[0092] As an example, when the tomosynthesis imaging is completed, the mammography apparatus 10 of this embodiment outputs a plurality of captured projection images 80 tThe image data is output to the console 12. The console 12 receives the multiple projection images 80 input from the mammography device 10. t The image data is stored in the storage unit 52.

[0093] A plurality of projection images 80 are stored in the memory unit 52. t After storing the image data, the console 12 executes the image processing shown in Fig. 8. Fig. 8 shows a flowchart showing an example of the flow of image processing by the console 12 of this embodiment. As an example, the console 12 of this embodiment executes the image processing shown in Fig. 8 by causing the CPU 50A of the control unit 50 to execute an image generating program 51 stored in the ROM 50B.

[0094] In step S100 of FIG. 8, the acquisition unit 60 acquires a plurality of projection images 80 t and multiple settings for irradiation position 19V t As described above, the first acquisition unit 60A of the acquisition unit 60 of this embodiment acquires the multiple projection images 80t from the storage unit 52. の The second acquisition unit 60B of the acquisition unit 60 acquires the image data. t The irradiation position in the setting that corresponds to 19V t Get the.

[0095] In the next step S102, the first tomographic image generating unit 62, the first three-dimensional position deriving unit 64, the first projection plane position deriving unit 66, the second projection plane position deriving unit 68, and the estimation unit 70 estimate the actual irradiation position 19 in the tomosynthesis imaging as described above. t and marker 90 i The actual three-dimensional position of the target object is estimated by the estimation process described below. t Coordinates and marker 90 i The coordinates of the actual three-dimensional position are output to the second tomographic image generating unit 74.

[0096] In the next step S104, the second tomographic image generating unit 74 executes the tomographic image generating process, the details of which will be described later, as described above, and obtains the irradiation position 19 estimated by the estimation process in the above step S104. t Using the position of t In this embodiment, the information on the mammary gland volume is also derived in the tomographic image generation process as described above.

[0097] In the next step S106, the display control unit 76 causes the display unit 58 to display the tomographic image generated in the above step S104 and the information on the derived mammary gland volume. When the processing in step S106 ends, the image processing shown in FIG. 8 ends. Note that the images and information displayed by the display control unit 76 are not limited to those in this embodiment. For example, the display control unit 76 may display the projection image 80 t The above may also be displayed.

[0098] Further, the details of the estimation process in step S102 of the image processing will be described below. Fig. 9 shows a flowchart showing an example of the flow of the estimation process.

[0099] In step S130 of FIG. 9, the first tomographic image generating unit 62 performs the image processing on the irradiation position 19V t As described above, the first tomographic image generating unit 62 of this embodiment uses the projection image 80t to generate a tomographic image 82 as a first tomographic image. t Using the above, k slice images 821-82 are generated from the projection images 801-807. k Generate.

[0100] In the next step S132, the first three-dimensional position deriving unit 64 derives the marker 90 from the tomographic image 82 generated in the above step S132. i As described above, the first three-dimensional position derivation unit 64 of the present embodiment derives the three-dimensional positions at which the markers 90 are arranged. i The position of the coordinates (mx i ,my i ,mz i ) is derived.

[0101] In the next step S134, the first projection plane position deriving unit 66 determines the projection position 19V t and marker 90 i From the position of the marker 90 projected on the projection surface 80A, i The projection plane position is derived.

[0102] In the next step S136, the estimation unit 70 derives the energy function E expressed by the above formula (3) based on the above formulas (1) and (2).

[0103] In the next step S138, the estimation unit 70 determines whether or not to end the estimation process. As an example, the estimation unit 70 in this embodiment determines to end the estimation process when a predetermined end condition is satisfied. An example of the end condition is a condition in which the process ends when the energy function E derived in the above step S136 is a minimum value. Another example of the end condition is a condition in which the process ends when the energy function E derived in the above step S136 is equal to or less than a predetermined threshold value.

[0104] If the energy function E derived in step S136 is not the minimum value, or if the energy function E derived in step S136 exceeds a predetermined threshold, and the end condition is not satisfied, the determination in step S138 is negative, and the process proceeds to step S140. In step S140, the update unit 72 of the estimation unit 70 updates the set irradiation position 19V, which is a parameter in deriving the energy function E. t Coordinates (sx t , sy t , sz t ) and Marker 90 i The coordinates (mx i ,my i ,mz i When the process of step S140 ends, the process returns to step S134, and the processes of steps S134 and S136 are repeated.

[0105] On the other hand, if the energy function E derived in step S136 is a minimum value, or if the energy function E derived in step S136 is equal to or smaller than a predetermined threshold value, or other termination conditions are satisfied, the determination in step S138 is affirmative. t Coordinates (sx t , sy t , sz t ) and Marker 90 i The coordinates (mx i ,my i ,mz i ) corresponds to the estimation result by this estimation process. If the determination in step S138 is a positive determination, the estimation process shown in FIG. 9 ends, and the process proceeds to step S104 of image processing. Note that the irradiation position 19V on the setting used for generating the tomographic image 82 in the first tomographic image generating unit 62 is t The irradiation position 19V in the setting that corresponds to this estimation result t By updating the setting, when this estimation process is performed in the next tomosynthesis image, the irradiation position 19V t and the actual irradiation position in tomosynthesis imaging19 t Since the difference between them can be reduced, the processing load in this estimation process can be reduced.

[0106] Further, details of the tomographic image generating process in step S104 of the image processing will be described below. Fig. 10 shows a flowchart showing an example of the flow of the tomographic image processing.

[0107] In step S150 of FIG. 10, the second tomographic image generating unit 74 generates the marker 90 estimated in the image processing step S102. i Based on the height (position in the Z-axis direction) of the breast, the thickness of the breast compressed by the compression paddle 38 is calculated.

[0108] In the next step S152, the second tomographic image generating unit 74 determines the highest position of the tomographic plane of the tomographic image to be generated as described above based on the breast thickness derived in the above step S150. As described above, the second tomographic image generating unit 74 of this embodiment determines the height according to the breast thickness derived in the above step S150 as the height of the tomographic image to be generated.

[0109] In the next step S154, the second tomographic image generating unit 74 estimates the amount of scattered radiation. As described above, the second tomographic image generating unit 74 estimates the amount of scattered radiation for each projection image 80 based on the breast thickness derived in the above step S150. t Estimate the amount of scattered radiation contained in the

[0110] In the next step S156, the second tomographic image generating unit 74 calculates the actual irradiation position 19 in the tomosynthesis imaging estimated in the image processing step S102. t Using the coordinates of the projection image 80 t As described above, the second tomographic image generating unit 74 applies a low-frequency component removal filter according to the amount of scattered radiation estimated in step S154 to generate a projection image 80. t A tomographic image is generated from the

[0111] In the next step S158, the second tomographic image generation unit 74 derives, as described above, information on the glandular volume of the breast, which is the subject U, based on the breast thickness derived in step S150. When the process of step S158 ends, the tomographic image generation process shown in Fig. 10 ends, and the process proceeds to image processing step S106.

[0112] As described above, the console 12 of the above embodiment has a plurality of irradiation positions 19 each having a different irradiation angle α. t The console 12 processes a plurality of projection images obtained by irradiating the subject U with radiation R from each of the radiation sources 29. The console 12 includes a CPU 50A. The CPU 50A places markers 90 between the plurality of irradiation positions 19t and the projection surface 80A. i With the laser placed at irradiation position 19, tMultiple cross-sectional images taken at each t and a plurality of projected images 80 t Each of the irradiation positions was set as a multiple setting of irradiation position 19V t And set the irradiation position on 19V t Using the projection image 80 t A tomographic image 82 is generated from the tomographic image 82, and a marker 90 is extracted from the tomographic image 82. i The three-dimensional coordinates (mx i ,my i ,mz i ) is derived, and the irradiation position on the setting is 19V t and marker 90 i 3D position coordinates (mx i ,my i ,mz i ) and the marker 90 projected onto the projection surface 80A. i The first two-dimensional coordinate (px' ti ,py' ti ) is derived, and the projection image 80 t Each of the markers 90 i Marker image 91 representing ti The marker 90 on the projection plane 80A derived from i The second two-dimensional coordinate (px ti ,py ti ) and the first two-dimensional coordinate (px' ti ,py' ti ) and based on the irradiation position 19 t Estimate.

[0113] According to the console 12 having the above configuration, the irradiation position of the radiation R can be derived with high accuracy. i The three-dimensional position of the object can also be derived with high accuracy.

[0114] In addition, Marker 90 i If the 3D position of the marker is inaccurate, i The two-dimensional position of the marker 30 may also become inaccurate, and the accuracy of deriving the irradiation position of the radiation R may decrease. i When deriving the irradiation position of radiation R using the marker 90 as a reference,i If the three-dimensional position of the marker 90 is inaccurate, the accuracy of deriving the irradiation position of the radiation R decreases. i The three-dimensional position of the object can be derived with high accuracy.

[0115] In addition, in tomosynthesis imaging, multiple projection images are taken, so the projection images may vary depending on the subject's body movements. t A misalignment may occur between the projected image 80 and the projected image 80. t Since the image quality of the tomographic image 82 is degraded by generating the tomographic image 82 using the above-mentioned method, the body movement of the subject may be corrected. t By correcting the body movement of the subject using the above, the accuracy of the body movement correction can be improved.

[0116] In the above embodiment, the console 12 is an example of the image processing device of the present disclosure, but a device other than the console 12 may have the functions of the image processing device of the present disclosure. In other words, some or all of the functions of the acquisition unit 60, the first tomographic image generation unit 62, the first three-dimensional position derivation unit 64, the first projection plane position derivation unit 66, the second projection plane position derivation unit 68, the estimation unit 70, the second tomographic image generation unit 74, and the display control unit 76 may be provided by a device other than the console 12, such as the mammography device 10 or an external device. In addition, the image processing device of the present disclosure may be configured by a plurality of devices. For example, some of the functions of the image processing device may be provided by a device other than the console 12.

[0117] In the above embodiment, a breast is applied as an example of a subject of the present disclosure, and a mammography device 10 is applied as an example of a radiation image capturing device of the present disclosure, but the subject is not limited to a breast, and the radiation image capturing device is not limited to a mammography device. For example, the subject may be a chest or abdomen, and the radiation image capturing device may be a radiation image capturing device other than a mammography device.

[0118] In the above embodiment, the following various processors can be used as the hardware structure of the processing units that execute various processes, such as the acquisition unit 60, the first tomographic image generation unit 62, the first three-dimensional position derivation unit 64, the first projection plane position derivation unit 66, the second projection plane position derivation unit 68, the estimation unit 70, the second tomographic image generation unit 74, and the display control unit 76. As described above, the above various processors include a CPU, which is a general-purpose processor that executes software (programs) and functions as various processing units, as well as a programmable logic device (PLD), which is a processor whose circuit configuration can be changed after manufacture, such as an FPGA (Field Programmable Gate Array), a dedicated electric circuit, which is a processor having a circuit configuration designed specifically for executing specific processes, such as an ASIC (Application Specific Integrated Circuit), etc.

[0119] A single processing unit may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, or a combination of a CPU and an FPGA). Also, multiple processing units may be configured with a single processor.

[0120] As an example of configuring multiple processing units with one processor, first, there is a form in which one processor is configured with a combination of one or more CPUs and software, and this processor functions as multiple processing units, as represented by computers such as client and server. Second, there is a form in which a processor is used to realize the functions of the entire system including multiple processing units with one IC (Integrated Circuit) chip, as represented by a system on chip (SoC). In this way, the various processing units are configured using one or more of the above various processors as a hardware structure.

[0121] Furthermore, more specifically, the hardware structure of these various processors can be an electric circuit that combines circuit elements such as semiconductor elements.

[0122] In the above embodiments, the photographing program 41 is pre-stored (installed) in the ROM 40B, and the image generating program 51 is pre-stored (installed) in the ROM 50B, but the present invention is not limited to this. Each of the photographing program 41 and the image generating program 51 may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a USB (Universal Serial Bus) memory. Each of the photographing program 41 and the image generating program 51 may be downloaded from an external device via a network. [Explanation of symbols]

[0123] 1 Radiography system 10 Mammography equipment 12 Console 191-197, 19 t Irradiation position, 19V t Irradiation position in settings 20 Radiation detector, 20A detection surface 24 Imaging Table, 24A Imaging Surface 28 Radiation Department 29 Radiation source 33 Arm section 34 Foundation 35 Shaft 36 Compression Unit 38 Compression plate, 38A Compression part, 38AA Top surface 39 Support part 40A, 50A CPU, 40B, 50B ROM, 40C, 50C RAM 41 Shooting Program 42, 52 Storage section 44, 54 I / F section 46, 56 Operation section 47 Source moving part 49, 59 Bus 51 Image Generation Program 58 Display section 60 Acquisition Department, 60A 1st Acquisition Department, 60B 2nd Acquisition Department 62 First tomographic image generating unit 64 First three-dimensional position derivation unit 66 First projection plane position derivation unit 68 Second projection plane position derivation unit 70 Estimation part 72 Update section 74 Second tomographic image generating unit 76 Display control section 801~807 projection image, 80A, 80A1~80A7 projection surface 821~82 k Tomographic images 90 i Marker 91 1i ~91 7i , 91 ti Marker image 92 1i ~92 7i , 94 i Marker Image CL normal R radiation, RC radiation axis U Subject α, β angles

Claims

1. 1. An image processing device that processes a plurality of projection images obtained by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles, comprising: At least one processor; The processor, With a marker disposed between the plurality of projection positions and a projection surface, a plurality of projection images photographed for each of the plurality of projection positions and a plurality of preset projection positions set as the respective projection positions of the plurality of projection images are acquired; generating a first tomographic image from the plurality of projection images using the plurality of set irradiation positions; Deriving a first three-dimensional position at which the marker is arranged from the first tomographic image; deriving a first projection plane position of the marker projected onto the projection plane from the irradiation positions on the plurality of settings and the first three-dimensional position of the marker; estimating the plurality of irradiation positions based on the first projection surface position and a second projection surface position of the marker on the projection surface identified from a marker image representing the marker included in each of the plurality of projection images; The subject is a breast compressed by a compression member, and the marker is provided on the compression member. Image processing device.

2. The processor, Estimating the plurality of projection positions at which the plurality of first projection plane positions and the plurality of second projection plane positions coincide with each other. The image processing device according to claim 1 .

3. The processor, Further estimating a second three-dimensional position of the marker based on the plurality of first projection plane positions and the plurality of second projection plane positions.

3. The image processing device according to claim 1 or 2.

4. The processor, A second tomographic image is generated from the plurality of projection images using the estimated plurality of irradiation positions. The image processing device according to any one of claims 1 to 3.

5. The processor, A second tomographic image is generated from the plurality of projection images using the estimated plurality of irradiation positions up to a height corresponding to a position in a height direction at the second three-dimensional position. The image processing device according to claim 3 .

6. The processor, Estimating a thickness of the compressed breast based on the second three-dimensional position.

6. The image processing device according to claim 3 or 5.

7. The processor, Deriving information about the glandular volume of the breast based on the thickness. The image processing device according to claim 6.

8. The processor, The amount of scattered radiation is estimated based on the thickness. The image processing device according to claim 6.

9. A state in which a plurality of the markers are arranged between the plurality of irradiation positions and the projection surface. The image processing device according to any one of claims 1 to 8.

10. The processor, The plurality of set irradiation positions and the first three-dimensional position are repeatedly updated to repeatedly derive the first projection surface position, thereby estimating the plurality of irradiation positions where the plurality of first projection surface positions and the second projection surface position coincide with each other. The image processing device according to any one of claims 1 to 9.

11. The markers are arranged in a plurality of locations according to a predetermined arrangement condition, The processor updates the first three-dimensional position within the range of the placement condition. The image processing device according to claim 10.

12. A radiation source that generates radiation; a radiation image capturing apparatus that performs tomosynthesis imaging by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles and capturing a projection image of the subject for each of the irradiation positions; An image processing device according to any one of claims 1 to 11, A radiation imaging system comprising:

13. 1. An image processing method for processing a plurality of projection images obtained by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles, the method comprising: With a marker disposed between the plurality of projection positions and a projection surface, a plurality of projection images photographed for each of the plurality of projection positions and a plurality of preset projection positions set as the respective projection positions of the plurality of projection images are acquired; generating a first tomographic image from the plurality of projection images using the plurality of set irradiation positions; Deriving a first three-dimensional position at which the marker is arranged from the first tomographic image; deriving a first projection plane position of the marker projected onto the projection plane from the irradiation positions on the plurality of settings and the first three-dimensional position of the marker; estimating the plurality of irradiation positions based on the first projection surface position and a second projection surface position of the marker on the projection surface identified from a marker image representing the marker included in each of the plurality of projection images; The subject is a breast compressed by a compression member, and the marker is provided on the compression member. An image processing method in which the processing is performed by a computer.

14. An image processing program for processing a plurality of projection images obtained by irradiating a subject with radiation from a radiation source from each of a plurality of irradiation positions having different irradiation angles, the program comprising: With a marker disposed between the plurality of projection positions and a projection surface, a plurality of projection images photographed for each of the plurality of projection positions and a plurality of preset projection positions set as the respective projection positions of the plurality of projection images are acquired; generating a first tomographic image from the plurality of projection images using the plurality of set irradiation positions; Deriving a first three-dimensional position at which the marker is arranged from the first tomographic image; deriving a first projection plane position of the marker projected onto the projection plane from the irradiation positions on the plurality of settings and the first three-dimensional position of the marker; estimating the plurality of irradiation positions based on the first projection surface position and a second projection surface position of the marker on the projection surface identified from a marker image representing the marker included in each of the plurality of projection images; The subject is a breast compressed by a compression member, and the marker is provided on the compression member. An image processing program that causes a computer to carry out the processing.

Images