Image processing apparatus, image processing method, and image processing program

Abstract

To reduce an exposure dose in CEDMBiopsy.SOLUTION: The image processing device 16 includes an CPU60A. The CPU60A acquires a series of a plurality of projected images or a plurality of tomographic images obtained by irradiating the mamma with radiations having a first energy and performing tomosynthesis imaging, and acquires a plurality of normal two dimensional images obtained by irradiating the mamma with radiations having a second energy higher than the first energy a plurality of times and performing imaging, For each of the plurality of normal two dimensional images, a virtual projection position, which is a position where the breast is virtually projected in tomosynthesis imaging, is calculated from the position of the radiation source when the normal two dimensional image is captured, a composite two dimensional image is generated from the plurality of projection images or the plurality of tomographic images based on the virtual projection position calculated for each of the plurality of normal two dimensional images, and a difference image between each of the plurality of normal two dimensional images and each of the composite two dimensional images generated for each of the plurality of normal two dimensional images is generated.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] A technique called CEDM (Contrast Enhanced Digital Mammography) Biopsy is known in which a breast injected with a contrast agent is irradiated with radiation of different energies to capture low-energy images and high-energy images, and a difference image between the high-energy and low-energy images is generated to generate a radiological image in which the contrast agent is enhanced. For example, Patent Document 1 describes an information processing device that captures high-energy images multiple times after capturing low-energy images and then generates difference images. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7446454 Summary of the Invention [Problem to be solved by the invention]

[0004] In CEDM biopsy, multiple sets of high-energy and low-energy images are taken while changing the angle of the radiation source, resulting in a high radiation dose. In particular, the radiation dose during low-energy imaging is high, so reducing the radiation dose is desirable.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide an image processing device, an image processing method, and an image processing program that can reduce the radiation dose in CEDM biopsy. [Means for solving the problem]

[0006] In order to achieve the above object, an image processing device of a first aspect of the present disclosure includes a processor, which acquires a series of multiple projection images or multiple tomographic images obtained by irradiating a breast with radiation of a first energy and performing tomosynthesis imaging, acquires multiple normal 2D images obtained by irradiating the breast multiple times with radiation of a second energy higher than the first energy, calculates a virtual projection position for each of the multiple normal 2D images, which is a position to virtually project the breast in the tomosynthesis imaging, from the position of the radiation source when the normal 2D image was captured, generates a composite 2D image from the multiple projection images or multiple tomographic images based on the virtual projection position calculated for each of the multiple normal 2D images, and generates a difference image between each of the multiple normal 2D images and each of the composite 2D images generated for each of the multiple normal 2D images.

[0007] In a second aspect of the image processing device of the present disclosure, in the image processing device of the first aspect, when the processor acquires the plurality of projection images, it generates the plurality of tomographic images from the plurality of projection images based on the virtual projection positions, and then generates the composite two-dimensional image from the plurality of tomographic images.

[0008] An image processing device of a third aspect of the present disclosure is the image processing device of the second aspect, wherein the processor generates the composite two-dimensional image from the plurality of tomographic images based on a projection path from the virtual projection position.

[0009] An image processing device of a fourth aspect of the present disclosure is the image processing device of the second aspect, wherein the processor generates the plurality of tomographic images by correcting the magnification ratio for each of the plurality of projection images centered on the virtual projection position, and generates the composite two-dimensional image by parallel projection of the generated plurality of tomographic images.

[0010] An image processing device of a fifth aspect of the present disclosure is the image processing device of the first aspect, wherein when the processor acquires the multiple tomographic images, the processor generates the composite two-dimensional image by combining the multiple tomographic images based on the virtual projection position.

[0011] An image processing device of a sixth aspect of the present disclosure is the image processing device of the first aspect, wherein the processor acquires the plurality of tomographic images with the magnification ratio corrected around the virtual projection position.

[0012] In a seventh aspect of the image processing device of the present disclosure, in the image processing device of the first aspect, the processor acquires the plurality of tomographic images, and if the plurality of tomographic images have not been corrected for magnification or the centers of magnification correction are at different positions, corrects the magnification of the plurality of tomographic images at the virtual projection position, and generates the composite two-dimensional image by parallel projection onto the corrected plurality of tomographic images.

[0013] An image processing device according to an eighth aspect of the present disclosure is the image processing device according to the first aspect, wherein the normal two-dimensional image includes a plurality of two-dimensional images captured while changing the position of the radiation source.

[0014] An image processing device of a ninth aspect of the present disclosure is the image processing device of the first aspect, wherein the processor controls to perform the tomosynthesis imaging again when movement of the breast is detected during the tomosynthesis imaging.

[0015] An image processing device of a tenth aspect of the present disclosure is the image processing device of the first aspect, wherein when the processor detects movement of the breast during the tomosynthesis imaging, the processor corrects the movement of the breast and generates the composite two-dimensional image.

[0016] An eleventh aspect of the image processing device of the present disclosure is an image processing device of the ninth or tenth aspect, in which the processor detects the movement of the breast by performing threshold processing on the difference between the normal two-dimensional image and the composite two-dimensional image.

[0017] An image processing device of a twelfth aspect of the present disclosure is the image processing device of the first aspect, wherein the processor controls to perform the tomosynthesis imaging again when a user's instruction is received after the tomosynthesis imaging.

[0018] An image processing device of a thirteenth aspect of the present disclosure includes a processor, which acquires a series of multiple projection images or multiple tomographic images obtained by irradiating a breast with radiation of a first energy and performing tomosynthesis imaging, acquires multiple normal two-dimensional images obtained by irradiating the breast multiple times with radiation of a second energy lower than the first energy, calculates, for each of the multiple normal two-dimensional images, a virtual projection position which is a position to virtually project the breast in the tomosynthesis imaging from the position of the radiation source when the normal two-dimensional image was captured, generates a composite two-dimensional image from the multiple projection images or multiple tomographic images based on the virtual projection position calculated for each of the multiple normal two-dimensional images, and generates a difference image between each of the multiple normal two-dimensional images and each of the composite two-dimensional images generated for each of the multiple normal two-dimensional images.

[0019] In a fourteenth aspect of the image processing method of the present disclosure, a computer executes the following processes: acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating a breast with radiation of a first energy and performing tomosynthesis imaging; acquiring multiple normal two-dimensional images obtained by irradiating the breast multiple times with radiation of a second energy higher than the first energy; calculating, for each of the multiple normal two-dimensional images, a virtual projection position at which the breast is virtually projected in the tomosynthesis imaging from the position of the radiation source when the normal two-dimensional image was captured; generating a composite two-dimensional image from the multiple projection images or multiple tomographic images based on the virtual projection position calculated for each of the multiple normal two-dimensional images; and generating a difference image between each of the multiple normal two-dimensional images and each of the composite two-dimensional images generated for each of the multiple normal two-dimensional images.

[0020] An image processing program of a fifteenth aspect of the present disclosure causes a computer to perform the following processes: acquire a series of multiple projection images or multiple tomographic images obtained by irradiating a breast with radiation of a first energy and performing tomosynthesis imaging; acquire multiple normal two-dimensional images obtained by irradiating the breast multiple times with radiation of a second energy higher than the first energy and performing tomosynthesis imaging; calculate, for each of the multiple normal two-dimensional images, a virtual projection position at which the breast is virtually projected in the tomosynthesis imaging from the position of the radiation source when the normal two-dimensional image was captured; generate a composite two-dimensional image from the multiple projection images or multiple tomographic images based on the virtual projection position calculated for each of the multiple normal two-dimensional images; and generate a difference image between each of the multiple normal two-dimensional images and each of the composite two-dimensional images generated for each of the multiple normal two-dimensional images. [Effects of the Invention]

[0021] According to the present disclosure, it is possible to reduce the radiation dose in CEDM biopsy. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a configuration diagram schematically illustrating an example of the overall configuration of a radiation image capturing system according to an embodiment; [Figure 2] FIG. 1 is a diagram illustrating an example of tomosynthesis imaging. [Figure 3] 1 is a block diagram illustrating an example of a configuration of an image processing apparatus according to an embodiment. [Figure 4] FIG. 1 is a diagram illustrating CEDM Biopsy according to a comparative example. [Figure 5] FIG. 1 is a diagram illustrating the processing flow of CEDM Biopsy according to a comparative example. [Figure 6] 1 is a block diagram showing an example of a functional configuration of an image processing apparatus according to a first embodiment. [Figure 7A] FIG. 10 is a diagram showing an example of capturing a high-energy normal two-dimensional image from the irradiation position of a radiation source. [Figure 7B] 10A and 10B are diagrams illustrating a calculation process of a virtual projection position corresponding to an irradiation position of a radiation source in tomosynthesis imaging. [Figure 8] FIG. 10 is a diagram illustrating a magnification ratio. [Figure 9] FIG. 2 is a diagram illustrating the processing flow of CEDM Biopsy according to the first embodiment. [Figure 10] FIG. 1 is a diagram illustrating CEDM Biopsy according to the first embodiment. [Figure 11] 5 is a flowchart showing an example of a processing flow by an image processing program according to the first embodiment. [Figure 12] 10 is a flowchart showing another example of the processing flow by the image processing program according to the first embodiment. [Figure 13] FIG. 10 is a diagram illustrating the processing flow of CEDM Biopsy according to the second embodiment. [Figure 14] FIG. 10 is a diagram illustrating CEDM Biopsy according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments.

[0024] [First embodiment] First, an example of the overall configuration of the radiographic imaging system of this embodiment will be described. Fig. 1 shows a configuration diagram illustrating an example of the overall configuration of the radiographic imaging system 1 of this embodiment. As shown in Fig. 1, the radiographic imaging system 1 of this embodiment includes a mammography apparatus 10, a console 12, a PACS (Picture Archiving and Communication Systems) 14, and an image processing device 16. The console 12, the PACS 14, and the image processing device 16 are connected via a network 17 by wired communication or wireless communication.

[0025] First, the mammography device 10 of this embodiment will be described. Figure 1 shows a side view of an example of the appearance of the mammography device 10 of this embodiment. Note that Figure 1 shows an example of the appearance of the mammography device 10 when viewed from the left side of the subject.

[0026] The mammography device 10 of this embodiment operates under the control of the console 12 and is an apparatus that takes a radiographic image of a subject's breast by irradiating the breast with radiation R (e.g., X-rays) from a radiation source 29. The radiation source 29 is, for example, a tube that irradiates the radiation R. The mammography device 10 of this embodiment has the functions of performing normal radiography, in which radiography is performed by positioning the radiation source 29 at an irradiation position normal to the detection surface 20A of the radiation detector 20, and so-called tomosynthesis radiography (described below), in which radiography is performed by moving the radiation source 29 to each of multiple irradiation positions. Tomosynthesis radiography is a function that generates a radiographic image equivalent to a normal two-dimensional image obtained by normal radiography by combining a series of multiple projection images obtained by irradiating the breast with radiation or multiple tomographic images generated from the series of projection images.

[0027] As shown in FIG. 1, the mammography apparatus 10 includes an imaging table 24, a base 26, an arm 28, and a compression unit 32.

[0028] A radiation detector 20 is disposed inside the imaging table 24. As shown in Fig. 2, in the mammography apparatus 10 of this embodiment, when imaging is performed, the breast U of the subject is positioned on the imaging surface 24A of the imaging table 24 by the user.

[0029] The radiation detector 20 detects radiation R that has passed through the subject's breast U. In detail, the radiation detector 20 detects radiation R that has entered the subject's breast U 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, the 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." The type of radiation detector 20 in this embodiment is not particularly limited, and may be, for example, an indirect conversion type radiation detector that converts radiation R into light and then converts the converted light into electric charges, or a direct conversion type radiation detector that directly converts radiation R into electric charges.

[0030] The compression plate 30 used to compress the breast when imaging is attached to a compression unit 32 provided on the imaging table 24, and is moved toward or away from the imaging table 24 (hereinafter referred to as the "up and down direction") by a compression plate drive unit (not shown) provided on the compression unit 32. By moving in the up and down direction, the compression plate 30 compresses the breast of the subject between itself and the imaging table 24.

[0031] The arm 28 can rotate relative to the base 26 via the shaft 27. The shaft 27 is fixed to the base 26, and the shaft 27 and arm 28 rotate together. The shaft 27 and the compression unit 32 of the imaging table 24 are each provided with a gear, and by switching between an engaged state and a disengaged state of these gears, the compression unit 32 of the imaging table 24 and the shaft 27 can be switched between a state in which they are connected and rotate together, and a state in which the shaft 27 is separated from the imaging table 24 and rotates freely. Note that the switching between transmitting and disengaging power to the shaft 27 is not limited to the gear, and various mechanical elements can be used. The arm 28 and the imaging table 24 can rotate independently relative to the base 26, with the shaft 27 as the rotation axis.

[0032] When performing tomosynthesis imaging in the mammography device 10, the radiation source 29 is moved sequentially to each of a plurality of irradiation positions with different irradiation angles by the rotation of the arm unit 28. 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. 2 shows a diagram for explaining an example of tomosynthesis imaging. Note that the compression paddle 30 is not shown in FIG. 2. In this embodiment, as shown in FIG. 2, the radiation source 29 is moved sequentially to each of the irradiation positions 19 with irradiation angles that differ by a predetermined angle β. t (t=1, 2, . . . , the maximum value is 7 in FIG. 2), in other words, the radiation detector 20 is moved to a position where the radiation R irradiates the detection surface 20A of the radiation detector 20 at different irradiation angles. t In the radiation imaging system 1, radiation R is irradiated from the radiation source 29 toward the breast U in response to an instruction from the console 12, and a radiation image is captured by the radiation detector 20. t and move to each of the irradiation positions 19 t When tomosynthesis imaging is performed to capture radiographic images, seven radiographic images are obtained in the example shown in Figure 2.

[0033] In tomosynthesis imaging, when describing a radiation image captured at each irradiation position 19 to distinguish it from other radiation images, it is called a "projection image," and multiple projection images captured in one tomosynthesis imaging are called a "series of multiple projection images."

[0034] 2, the irradiation angle of radiation R refers to the angle α formed between a normal CL to the detection surface 20A of the radiation detector 20 and a radiation axis RC. The radiation axis RC is an axis connecting the focal point of the radiation source 29 at each irradiation position 19 and a predetermined position such as the center of the detection surface 20A. Here, the detection surface 20A of the radiation detector 20 is assumed to be a surface that is approximately parallel to the imaging surface 24A.

[0035] On the other hand, when performing normal imaging in the mammography device 10, the radiation source 29 is positioned at the irradiation position 19 where the irradiation angle α is 0 degrees. t(Irradiation position along the normal direction 19 t 2 ), the radiation source 29 irradiates the patient with radiation R, and the radiation detector 20 captures a radiographic image. In this embodiment, a radiographic image captured in normal radiography is referred to as a "normal two-dimensional image" to distinguish it from other radiographic images.

[0036] The mammography device 10 and the console 12 are connected by wired or wireless communication. A radiographic image captured by the radiation detector 20 in the mammography device 10 is output to the console 12 by wired or wireless communication via a communication I / F (Interface) unit (not shown).

[0037] As shown in FIG. 1, the console 12 of this embodiment includes a control unit 40, a storage unit 42, a user I / F unit 44, and a communication I / F unit 46.

[0038] As described above, the control unit 40 of the console 12 has the function of controlling the capture of radiographic images of the breast by the mammography device 10. The control unit 40 may be, for example, a computer system equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory).

[0039] The storage unit 42 has a function of storing information related to radiographic image capture, radiographic images acquired from the mammography apparatus 10, etc. The storage unit 42 is a non-volatile storage unit, such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0040] The user I / F unit 44 includes input devices such as various buttons and switches operated by users such as technicians in relation to radiographic imaging, and display devices such as lamps and displays that display information about imaging, radiographic images, etc.

[0041] The communication I / F unit 46 communicates various data, such as information related to radiographic image capture and radiographic images obtained by capture, with the mammography apparatus 10 via wired or wireless communication. The communication I / F unit 46 also communicates various data, such as radiographic images, with the PACS 14 and image processing device 16 via the network 17 via wired or wireless communication.

[0042] 1, the PACS 14 of this embodiment includes a storage unit 50 and a communication I / F unit (not shown) that store a radiographic image group 52. The radiographic image group 52 includes radiographic images captured by the mammography device 10 and acquired from the console 12 via the communication I / F unit (not shown).

[0043] The image processing device 16 is used when a doctor or the like (hereinafter simply referred to as "doctor") interprets a radiological image. The image processing device 16 according to this embodiment has a function of generating a composite two-dimensional image from a series of multiple projection images or multiple tomographic images. Multiple tomographic images can be obtained from a series of multiple projection images. Multiple tomographic images are generated by reconstructing a series of multiple projection images using, for example, a simple back projection method, a filtered back projection method, an iterative reconstruction method, or the like. A "composite two-dimensional image" is a pseudo two-dimensional image generated by combining multiple tomographic images. A composite two-dimensional image is generated by combining multiple tomographic images at different distances (height direction positions) from the detection surface 20A of the radiation detector 20 toward the radiation source 29 using, for example, an addition method, an averaging method, a maximum intensity projection method, a minimum intensity projection method, or the like.

[0044] Fig. 3 is a block diagram showing an example of the configuration of the image processing device 16 of this embodiment. As shown in Fig. 3, the image processing device 16 of this embodiment includes a control unit 60, a storage unit 62, a display unit 70, an operation unit 72, and a communication I / F unit 74. The control unit 60, the storage unit 62, the display unit 70, the operation unit 72, and the communication I / F unit 74 are connected via a bus 79 such as a system bus or a control bus so that various information can be exchanged between them.

[0045] The control unit 60 controls the overall operation of the image processing device 16. The control unit 60 includes a CPU 60A, a ROM 60B, and a RAM 60C. The ROM 60B stores various programs and the like for control by the CPU 60A in advance. The RAM 60C temporarily stores various data.

[0046] The storage unit 62 is a non-volatile storage unit, and specific examples include an HDD, an SSD, etc. The storage unit 62 stores an image processing program 62A according to this embodiment.

[0047] The display unit 70 displays radiographic images and various types of information. The display unit 70 is not particularly limited and may be any of various displays. The operation unit 72 is used by the user to input instructions and various types of information for a doctor to diagnose breast lesions using radiographic images. The operation unit 72 is not particularly limited and may be, for example, any of various switches, a touch panel, a touch pen, a mouse, etc. The display unit 70 and the operation unit 72 may be integrated into a touch panel display.

[0048] The communication I / F unit 74 communicates various types of information with the console 12 and the PACS 14 via the network 17 by wireless or wired communication.

[0049] FIG. 4 is a diagram illustrating a CEDM biopsy according to a comparative example. In the CEDM biopsy, a normal two-dimensional image (hereinafter referred to as a "low-energy normal two-dimensional image") captured by irradiating a predetermined irradiation position of the radiation source 29 with radiation of a first energy and a normal two-dimensional image (hereinafter referred to as a "high-energy normal two-dimensional image") captured by irradiating a predetermined irradiation position of the radiation source 29 with radiation of a second energy higher than the first energy are acquired, and a subtraction image between the low-energy normal two-dimensional image and the high-energy normal two-dimensional image is created. In the CEDM biopsy, since deviation of the irradiation position of the radiation source 29 results in an error, a high-energy normal two-dimensional image and a low-energy normal two-dimensional image are acquired as a set at the same irradiation position. In the example of FIG. 4, a low-energy normal two-dimensional image LE1 and a high-energy normal two-dimensional image HE1 are acquired at the irradiation position P1 of the radiation source 29, and a subtraction image ES1 between the low-energy normal two-dimensional image LE1 and the high-energy normal two-dimensional image HE1 is created. Furthermore, by changing the angle, a low-energy normal two-dimensional image LE2 and a high-energy normal two-dimensional image HE2 are acquired at irradiation position P2 of radiation source 29, and a difference image ES2 between the low-energy normal two-dimensional image LE2 and the high-energy normal two-dimensional image HE2 is created. In other words, the position of lesion L can be identified three-dimensionally using the stereo principle. Note that when there is no need to particularly distinguish between the high-energy normal two-dimensional image, the low-energy normal two-dimensional image, and the difference image, they will be referred to as the high-energy normal two-dimensional image HE, the low-energy normal two-dimensional image LE, and the difference image ES.

[0050] FIG. 5 is a diagram illustrating the processing flow of CEDM Biopsy according to a comparative example.

[0051] 5, scout imaging (positioning) is performed for positioning. In the scout imaging, a high-energy normal two-dimensional image HE and a low-energy normal two-dimensional image LE are captured.

[0052] In (S202), stereo imaging (needle insertion positioning) is performed to determine the position of the needle to be inserted into the breast U. In this stereo imaging, for example, a high-energy normal two-dimensional image HE1 and a low-energy normal two-dimensional image LE1 are captured at an irradiation position P1 of the radiation source 29, and then a high-energy normal two-dimensional image HE2 and a low-energy normal two-dimensional image LE2 are captured at an irradiation position P2 of the radiation source 29 by changing the angle.

[0053] In (S203), stereo imaging (needle position confirmation) is performed to confirm the position after the needle has been inserted into the breast U. The stereo imaging at this time is also performed at irradiation positions P1 and P2, similar to the stereo imaging in (S202) above.

[0054] In (S204), stereo photography (aspiration confirmation) is performed to check the state after the tissue has been aspirated through the needle hole. Similar to the stereo photography in (S202), stereo photography at this time is also performed at irradiation positions P1 and P2.

[0055] As described above, in CEDM Biopsy, a set of high-energy normal two-dimensional images HE and low-energy normal two-dimensional images LE is captured multiple times while changing the angle of the radiation source 29, resulting in a high radiation dose. In particular, the radiation dose when capturing low-energy normal two-dimensional images LE is high, so it is desirable to reduce the radiation dose.

[0056] In the radiographic imaging system 1 according to this embodiment, tomosynthesis imaging is performed using low-energy radiation to capture a high-energy normal two-dimensional image HE. The radiographic imaging system 1 then generates a low-energy composite two-dimensional image by virtually projecting multiple projection images or multiple tomographic images obtained by tomosynthesis imaging from the irradiation position of the radiation source 29 when the high-energy normal two-dimensional image HE was captured. Hereinafter, the low-energy composite two-dimensional image will be referred to as a low-energy composite two-dimensional image LEs to distinguish it from the low-energy normal two-dimensional image LE. The radiographic imaging system 1 then generates a difference image ES between the high-energy normal two-dimensional image HE and the low-energy composite two-dimensional image LEs. In other words, compared to the CEDM biopsy according to the comparative example, only one low-energy tomosynthesis imaging is required, thereby enabling a reduction in radiation exposure dose.

[0057] Specifically, the CPU 60A of the image processing device 16 according to this embodiment writes an image processing program 62A stored in the storage unit 25 into the RAM 60C and executes it, thereby functioning as each unit shown in FIG.

[0058] 6 is a block diagram showing an example of the functional configuration of the image processing device 16 according to the first embodiment. The CPU 60A of the image processing device 16 according to this embodiment functions as a first acquisition unit 101, a second acquisition unit 102, a calculation unit 103, a first generation unit 104, and a second generation unit 105. Although the first acquisition unit 101 and the second acquisition unit 102 are distinguished for convenience, they may be realized as a single acquisition unit. Similarly, although the first generation unit 104 and the second generation unit 105 are distinguished for convenience, they may be realized as a single generation unit. In this embodiment, the first energy is low energy, and the second energy is high energy.

[0059] The first acquisition unit 101 acquires a series of multiple projection images or multiple tomographic images. These multiple projection images or multiple tomographic images are images obtained by irradiating the breast U with low-energy radiation and performing tomosynthesis imaging.

[0060] The second acquisition unit 102 acquires multiple normal 2D images captured by irradiating the breast U with high-energy radiation multiple times. In the example of FIG. 5 described above, "multiple times" refers to four times: "positioning," "needle insertion positioning," "needle position confirmation," and "suction confirmation." In other words, four high-energy normal 2D images HE are captured. However, stereo imaging is performed at different angles for "needle insertion positioning," "needle position confirmation," and "suction confirmation," but the stereo imaging is counted as one image, just like scout imaging.

[0061] For each of the multiple high-energy normal two-dimensional images HE, the calculation unit 103 calculates a virtual projection position in tomosynthesis imaging from the irradiation position of the radiation source 29 when the high-energy normal two-dimensional image HE was captured. The virtual projection position is a position onto which the breast U is virtually projected in tomosynthesis imaging. Note that since stereo imaging is performed for "needle insertion positioning," "needle position confirmation," and "suction confirmation," it is sufficient to calculate a virtual projection position corresponding to each irradiation position in stereo imaging.

[0062] The first generating unit 104 generates a low-energy composite two-dimensional image LEs from a plurality of projection images or a plurality of tomographic images based on the virtual projection positions calculated for each of a plurality of high-energy ordinary two-dimensional images HE.

[0063] The second generating unit 105 generates a difference image ES between each of the multiple high-energy ordinary two-dimensional images HE and each of the low-energy synthesized two-dimensional images LEs generated for each of the multiple high-energy ordinary two-dimensional images HE.

[0064] Here, the virtual projection position calculation process according to the first embodiment will be specifically described with reference to FIGS. 7A and 7B.

[0065] Fig. 7A is a diagram showing an example of capturing a high-energy normal two-dimensional image HE from an irradiation position P1 of the radiation source 29. Fig. 7B is a diagram explaining a calculation process of a virtual projection position P4 corresponding to the irradiation position P1 of the radiation source 29 in tomosynthesis imaging.

[0066] 7A, the irradiation position P1 of the radiation source 29 is, for example, shifted to the left side from the normal line CL. A high-energy normal two-dimensional image HE is generated by irradiating the breast U with high-energy radiation from the irradiation position P1 and performing normal imaging.

[0067] As shown in FIG. 7B , assume that low-energy radiation is irradiated onto the breast U from irradiation position P3 of radiation source 29 during tomosynthesis imaging. This irradiation position P3 is one of multiple irradiation positions in tomosynthesis imaging and serves as the reference position for tomosynthesis imaging. In this case, because irradiation position P1 and irradiation position P3 are different positions, the position of lesion L in projection image LEp captured at irradiation position P3 is shifted from the position of lesion L in high-energy normal two-dimensional image HE captured at irradiation position P1. Therefore, to align the position of lesion L with the high-energy normal two-dimensional image HE, calculation unit 103 calculates a corresponding virtual projection position P4 from irradiation position P1 in the high-energy normal two-dimensional image HE. Specifically, for example, the difference between irradiation position P1 in the high-energy normal two-dimensional image HE and irradiation position P3 in projection image LEp may be calculated, and irradiation position P3 may be corrected based on the calculated difference. Virtual projection position P4 is calculated for each irradiation position in tomosynthesis imaging based on the calculated difference. That is, since tomosynthesis imaging involves successive imaging at multiple irradiation positions, the virtual projection positions corresponding to each irradiation position can be calculated by correcting each irradiation position according to the difference. The first generation unit 104 generates a low-energy composite two-dimensional image LEs from the multiple projection images or multiple tomographic images based on the calculated virtual projection position P4.

[0068] Next, a case will be described in which projection images are acquired without acquiring tomographic images, and a low-energy composite two-dimensional image LEs is generated using a virtual projection position P4 as an example. The first acquisition unit 101 acquires a plurality of projection images. When acquiring a plurality of projection images, the first generation unit 104 generates a plurality of tomographic images from the plurality of projection images based on the virtual projection position P4, and then generates a low-energy composite two-dimensional image LEs from the plurality of tomographic images.

[0069] Furthermore, the first generation unit 104 may generate a low-energy composite two-dimensional image LEs from a plurality of tomographic images based on a projection path from the virtual projection position P4. That is, the first generation unit 104 generates a plurality of tomographic images from a plurality of projection images without correcting the magnification ratio, and generates a low-energy composite two-dimensional image LEs by projecting the plurality of tomographic images from the virtual projection position P4.

[0070] FIG. 8 is a diagram illustrating the magnification ratio. The first generation unit 104 may generate multiple tomographic images by correcting the magnification ratio for each of the multiple projection images, centered on a virtual projection position P4, and generate a low-energy composite two-dimensional image LEs by performing parallel projection on the multiple generated tomographic images. In the example of FIG. 8, the irradiation position P3 of the radiation source 29 is corrected to the corresponding virtual projection position P4. However, the magnification ratio X1 obtained when a cone-beam-shaped radiation is irradiated centered on the irradiation position P3 is different from the magnification ratio X2 obtained when a cone-beam-shaped radiation is irradiated centered on the virtual projection position P4. Therefore, multiple tomographic images are generated by correcting the magnification ratio X1 to the magnification ratio X2 for each of the multiple projection images.

[0071] Next, a case will be described in which a tomographic image is acquired instead of a projection image, and a low-energy composite two-dimensional image LEs is generated using a virtual projection position P4 as an example. The first acquisition unit 101 acquires a plurality of tomographic images. When the plurality of tomographic images are acquired, the first generation unit 104 generates a low-energy composite two-dimensional image LEs by combining the plurality of tomographic images based on the virtual projection position P4.

[0072] The first acquisition unit 101 may also acquire a plurality of tomographic images with the magnification ratio corrected around the virtual projection position P4. In this case, the first generation unit 104 generates a low-energy composite two-dimensional image LEs by performing parallel projection on the acquired plurality of tomographic images. That is, the magnification ratio of the tomographic images themselves may be corrected at the virtual projection position P4 calculated from the high-energy normal two-dimensional image HE, and the low-energy composite two-dimensional image LEs may be generated from the tomographic images with the magnification ratio corrected.

[0073] In addition, if the acquired multiple tomographic images have not been corrected for magnification or the centers of magnification correction are at different positions, the first generation unit 104 may correct the magnification of the multiple tomographic images at a virtual projection position P4 and generate a low-energy composite two-dimensional image LEs by parallel projection onto the corrected multiple tomographic images.

[0074] Next, the CEDM Biopsy according to the first embodiment will be specifically described with reference to FIGS.

[0075] Fig. 9 is a diagram illustrating the processing flow of CEDM Biopsy according to the first embodiment, and Fig. 10 is a diagram illustrating CEDM Biopsy according to the first embodiment.

[0076] In (S1) of FIG. 9, low-energy radiation is irradiated onto the breast U to perform tomosynthesis imaging, thereby obtaining a series of multiple projection images or multiple tomographic images.

[0077] In (S2), scout imaging (positioning) is performed to determine the position. In scout imaging, a high-energy normal two-dimensional image HE is captured at the irradiation position for scout imaging, and a corresponding virtual projection position in tomosynthesis imaging is calculated from the irradiation position of the high-energy normal two-dimensional image HE. Then, based on the calculated virtual projection position, a low-energy composite two-dimensional image LEs is generated from multiple projection images or multiple tomographic images obtained by tomosynthesis imaging. Note that the irradiation position for scout imaging may be, for example, irradiation position P1 or irradiation position P2 shown in FIG. 10, or an irradiation position other than irradiation positions P1 and P2.

[0078] In step (S3), stereo imaging (needle insertion positioning) is performed to determine the position of the needle to be inserted into the breast U. In this stereo imaging, for example, as shown in FIG. 10 , a high-energy normal two-dimensional image HE1 is captured at irradiation position P1 of the radiation source 29, and then a high-energy normal two-dimensional image HE2 is captured at irradiation position P2 of the radiation source 29 by changing the angle. Then, from the irradiation position P1 of the high-energy normal two-dimensional image HE1, a corresponding virtual projection position P4 in tomosynthesis imaging is calculated, and a low-energy composite two-dimensional image LEs1 is generated from multiple projection images or multiple tomographic images based on the calculated virtual projection position P4. Similarly, from the irradiation position P2 of the high-energy normal two-dimensional image HE2, a corresponding virtual projection position P5 in tomosynthesis imaging is calculated, and a low-energy composite two-dimensional image LEs2 is generated from multiple projection images or multiple tomographic images based on the calculated virtual projection position P5. Then, as shown in FIG. 10, a difference image ES1 between the high-energy normal two-dimensional image HE1 and the low-energy composite two-dimensional image LEs1 is generated, and a difference image ES2 between the high-energy normal two-dimensional image HE2 and the low-energy composite two-dimensional image LEs2 is generated.

[0079] In (S4), stereo imaging (needle position confirmation) is performed to confirm the position after the needle has been inserted into the breast U. In this stereo imaging, similar to the stereo imaging in (S3) above, high-energy normal two-dimensional images HE1 and HE2 are captured at irradiation positions P1 and P2, and low-energy composite two-dimensional images LEs1 and LEs2 are generated from multiple projection images or multiple tomographic images obtained by tomosynthesis imaging based on the calculated virtual projection positions P4 and P5. Then, a difference image ES1 between the high-energy normal two-dimensional image HE1 and the low-energy composite two-dimensional image LEs1 is generated, and a difference image ES2 between the high-energy normal two-dimensional image HE2 and the low-energy composite two-dimensional image LEs2 is generated.

[0080] In (S5), stereo imaging (suction confirmation) is performed to confirm the state after the tissue has been aspirated through the needle hole. Similar to the stereo imaging in (S3), high-energy normal two-dimensional images HE1 and HE2 are captured at irradiation positions P1 and P2, and low-energy composite two-dimensional images LEs1 and LEs2 are generated from multiple projection images or multiple tomographic images obtained by tomosynthesis imaging based on the calculated virtual projection positions P4 and P5. A difference image ES1 between the high-energy normal two-dimensional image HE1 and the low-energy composite two-dimensional image LEs1 is then generated, and a difference image ES2 between the high-energy normal two-dimensional image HE2 and the low-energy composite two-dimensional image LEs2 is also generated.

[0081] Here, the high-energy normal two-dimensional image HE includes a plurality of two-dimensional images captured by changing the irradiation position of the radiation source 29. In the examples of Figures 9 and 10, a high-energy normal two-dimensional image HE1 is captured at irradiation position P1, and a high-energy normal two-dimensional image HE2 is captured at irradiation position P2 by changing the angle.

[0082] Furthermore, if the first acquisition unit 101 detects movement of the breast U during tomosynthesis imaging, it may control the mammography apparatus 10 to perform tomosynthesis imaging again. Specifically, for example, it may display a message urging the mammography apparatus 10 to perform tomosynthesis imaging again. Alternatively, it may transmit an instruction signal to the mammography apparatus 10 to instruct the mammography apparatus 10 to perform tomosynthesis imaging again.

[0083] Furthermore, when the first generating unit 104 detects movement of the breast U during tomosynthesis imaging, it may correct the movement of the breast U to generate a low-energy composite two-dimensional image LEs. Specifically, for example, it may detect the amount of change in the position of the breast U, and correct the movement of the breast U based on the detected amount of change.

[0084] Furthermore, the first acquisition unit 101 may detect the movement of the breast U by performing threshold processing on the difference between the high-energy normal two-dimensional image HE and the low-energy composite two-dimensional image LE. In other words, if the breast U moves during tomosynthesis imaging, the position of the breast U (i.e., the lesion L) in the low-energy composite two-dimensional image LE will be shifted. Therefore, it is possible to determine that the breast U has moved when the difference between the high-energy normal two-dimensional image HE and the low-energy composite two-dimensional image LE is equal to or greater than a threshold. The movement of the breast U may also be detected using, for example, a sensor, a camera (not shown), or the like.

[0085] Furthermore, the first acquisition unit 101 may perform control to perform tomosynthesis imaging again when a user's instruction is received after tomosynthesis imaging. Specifically, for example, after tomosynthesis imaging, if the user checks the low-energy composite two-dimensional image LE and determines that tomosynthesis imaging should be performed again, a screen for receiving an instruction to perform tomosynthesis imaging again may be displayed.

[0086] Next, the operation of the image processing device 16 according to the first embodiment will be described with reference to FIGS.

[0087] Fig. 11 is a flowchart showing an example of the flow of processing by the image processing program 62A according to the first embodiment. Fig. 11 describes a case where a projection image is acquired without acquiring a tomographic image.

[0088] First, when the image processing device 16 receives an instruction to start image processing, the CPU 60A reads and executes the image processing program 62A.

[0089] In step S101 of Fig. 11, the CPU 60A acquires a series of projection images by tomosynthesis imaging, as shown in Fig. 9 above, for example. The series of projection images are images obtained by irradiating the breast U with low-energy radiation and performing tomosynthesis imaging.

[0090] In step S102, the CPU 60A acquires multiple high-energy normal two-dimensional images HE obtained by irradiating the breast U with high-energy radiation multiple times, as shown in Fig. 9 above, for example. In the example of Fig. 9, four high-energy normal two-dimensional images HE are acquired: "positioning," "needle insertion positioning," "needle position confirmation," and "suction confirmation." Furthermore, since stereo imaging is performed for "needle insertion positioning," "needle position confirmation," and "suction confirmation," high-energy normal two-dimensional images HE are acquired for each of the stereo imaging.

[0091] In step S103, as an example, as shown in Figures 9 and 10 above, for each of the multiple high-energy normal two-dimensional images HE, the CPU 60A calculates virtual projection positions P4 and P5, which are positions where the breast U is virtually projected in tomosynthesis imaging, from the irradiation positions P1 and P2 of the radiation source 29 when the high-energy normal two-dimensional image HE was captured.

[0092] In step S104, CPU 60A determines whether or not to correct the magnification ratio for each of the series of multiple projection images, with virtual projection positions P4 and P5 as the center. If it is determined that the magnification ratio should be corrected (if the determination is affirmative), the process proceeds to step S105, and if it is determined that the magnification ratio should not be corrected (if the determination is negative), the process proceeds to step S107.

[0093] In step S105, CPU 60A corrects the magnification of each of the series of multiple projection images with virtual projection positions P4 and P5 as the center, thereby generating multiple tomographic images.

[0094] In step S106, the CPU 60A generates a low-energy composite two-dimensional image LEs by parallel projection of the generated plurality of tomographic images, and ends a series of processes by the image processing program 62A.

[0095] On the other hand, in step S107, CPU 60A generates a plurality of tomographic images for each of the series of a plurality of projection images without correcting the magnification ratio.

[0096] In step S108, the CPU 60A generates a low-energy composite two-dimensional image LEs by projecting the generated tomographic images from virtual projection positions P4 and P5, and ends a series of processes by the image processing program 62A.

[0097] Fig. 12 is a flowchart showing another example of the flow of processing by the image processing program 62A according to the first embodiment. Fig. 12 describes a case where a tomographic image is acquired instead of a projection image.

[0098] First, when the image processing device 16 receives an instruction to start image processing, the CPU 60A reads and executes the image processing program 62A.

[0099] 12, the CPU 60A acquires a plurality of tomographic images by tomosynthesis imaging. The plurality of tomographic images are images obtained by irradiating the breast U with low-energy radiation and performing tomosynthesis imaging.

[0100] In step S112, the CPU 60A acquires multiple high-energy normal two-dimensional images HE obtained by irradiating the breast U with high-energy radiation multiple times, as shown in Fig. 9 above, for example. In the example of Fig. 9, four high-energy normal two-dimensional images HE are acquired: "positioning," "needle insertion positioning," "needle position confirmation," and "suction confirmation." Furthermore, since stereo imaging is performed for "needle insertion positioning," "needle position confirmation," and "suction confirmation," high-energy normal two-dimensional images HE are acquired for each of the stereo imaging.

[0101] In step S113, as an example, as shown in Figures 9 and 10 above, for each of the multiple high-energy normal two-dimensional images HE, the CPU 60A calculates virtual projection positions P4 and P5, which are positions where the breast U is virtually projected in tomosynthesis imaging, from the irradiation positions P1 and P2 of the radiation source 29 when the high-energy normal two-dimensional image HE was captured.

[0102] In step S114, CPU 60A determines whether or not the magnification ratios of the acquired multiple tomographic images have been corrected around the virtual projection position. If it is determined that the magnification ratios have not been corrected (in the case of a negative determination), the process proceeds to step S115, and if it is determined that the magnification ratios have been corrected (in the case of a positive determination), the process proceeds to step S116.

[0103] In step S115, the CPU 60A generates a low-energy composite two-dimensional image LEs by projecting the acquired multiple tomographic images from the calculated virtual projection positions P4 and P5, and ends a series of processes by the image processing program 62A.

[0104] On the other hand, in step S116, the CPU 60A generates a low-energy composite two-dimensional image LEs by performing parallel projection on the acquired multiple tomographic images, and then ends a series of processes by the image processing program 62A.

[0105] In addition, if the magnification ratios of the multiple tomographic images acquired in step S111 have not been corrected around the virtual projection positions P4 and P5, or if the centers of the magnification ratio corrections are at different positions, the magnification ratios of the multiple tomographic images may be corrected using the virtual projection positions P4 and P5 calculated in step S113, and a low-energy composite two-dimensional image LEs may be generated by parallel projection.

[0106] As described above, according to this embodiment, in CEDM biopsy, only one low-energy tomosynthesis imaging, which involves a particularly high radiation dose, is required, thereby enabling a reduction in radiation dose compared to the CEDM biopsy of the comparative example. Note that, although multiple consecutive imaging sessions are performed in tomosynthesis imaging, the radiation dose at this time is less than the radiation dose at multiple low-energy normal imaging sessions.

[0107] Furthermore, since low-energy tomosynthesis imaging only requires one session, there is no need to capture a set of high-energy and low-energy normal 2D images, thereby shortening imaging time.

[0108] [Second embodiment] In the first embodiment, a configuration in which tomosynthesis imaging is used for imaging at low energy has been described, whereas in the second embodiment, a configuration in which tomosynthesis imaging is used for imaging at high energy will be described.

[0109] First, the functional configuration of an image processing device 16A according to the second embodiment will be described with reference to the above-mentioned Fig. 6. In the second embodiment, the first energy is high energy, and the second energy is low energy.

[0110] The first acquisition unit 101 acquires a series of multiple projection images or multiple tomographic images. These series of multiple projection images or multiple tomographic images are images obtained by irradiating the breast U with high-energy radiation and performing tomosynthesis imaging.

[0111] The second acquisition unit 102 acquires a plurality of low-energy normal two-dimensional images LE obtained by irradiating the breast U with low-energy radiation a plurality of times and capturing the images.

[0112] For each of the multiple low-energy normal two-dimensional images LE, the calculation unit 103 calculates a virtual projection position, which is the position where the breast U is virtually projected in tomosynthesis imaging, from the irradiation position of the radiation source 29 when the low-energy normal two-dimensional image LE is captured.

[0113] The first generation unit 104 generates a high-energy composite two-dimensional image from the multiple projection images or multiple tomographic images based on the virtual projection positions calculated for each of the multiple low-energy normal two-dimensional images LE. Hereinafter, the generated high-energy composite two-dimensional image will be referred to as a high-energy composite two-dimensional image HEs to distinguish it from the high-energy normal two-dimensional image HE.

[0114] The second generating unit 105 generates a difference image ES between each of the multiple low-energy ordinary two-dimensional images LE and each of the high-energy composite two-dimensional images HEs generated for each of the multiple low-energy ordinary two-dimensional images LE.

[0115] Fig. 13 is a diagram illustrating the processing flow of CEDM Biopsy according to the second embodiment, and Fig. 14 is a diagram illustrating CEDM Biopsy according to the second embodiment.

[0116] In (S11) of FIG. 13, high-energy radiation is irradiated onto the breast U to perform tomosynthesis imaging, thereby obtaining a series of multiple projection images or multiple tomographic images.

[0117] In (S12), scout imaging (positioning) is performed to determine position. In scout imaging, a low-energy normal two-dimensional image LE is captured at an irradiation position for scout imaging, and a corresponding virtual projection position in tomosynthesis imaging is calculated from the irradiation position of the low-energy normal two-dimensional image LE. Then, based on the calculated virtual projection position, a high-energy composite two-dimensional image HEs is generated from multiple projection images or multiple tomographic images obtained by tomosynthesis imaging. Note that the irradiation position for scout imaging may be, for example, irradiation position P1 or irradiation position P2 shown in FIG. 14, or an irradiation position other than irradiation positions P1 and P2.

[0118] In step S13, stereo imaging (needle insertion positioning) is performed to determine the position of the needle to be inserted into the breast U. In this stereo imaging, for example, as shown in FIG. 14, a low-energy normal two-dimensional image LE1 is captured at an irradiation position P1 of the radiation source 29, and then a low-energy normal two-dimensional image LE2 is captured at an irradiation position P2 of the radiation source 29 by changing the angle. Then, from the irradiation position P1 of the low-energy normal two-dimensional image LE1, a corresponding virtual projection position P4 in tomosynthesis imaging is calculated, and a high-energy composite two-dimensional image HEs1 is generated from multiple projection images or multiple tomographic images based on the calculated virtual projection position P4. Similarly, from the irradiation position P2 of the low-energy normal two-dimensional image LE2, a corresponding virtual projection position P5 in tomosynthesis imaging is calculated, and a high-energy composite two-dimensional image HEs2 is generated from multiple projection images or multiple tomographic images based on the calculated virtual projection position P5. Then, as shown in FIG. 14, a difference image ES1 between the low-energy normal two-dimensional image LE1 and the high-energy composite two-dimensional image HEs1 is generated, and a difference image ES2 between the low-energy normal two-dimensional image LE2 and the high-energy composite two-dimensional image HEs2 is generated.

[0119] In (S14), stereo imaging (needle position confirmation) is performed to confirm the position after the needle has been inserted into the breast U. In this stereo imaging, as in the stereo imaging in (S13) above, low-energy normal two-dimensional images LE1 and LE2 are captured at irradiation positions P1 and P2, and high-energy composite two-dimensional images HEs1 and HEs2 are generated from multiple projection images or multiple tomographic images obtained by tomosynthesis imaging based on the calculated virtual projection positions P4 and P5. Then, a difference image ES1 between the low-energy normal two-dimensional image LE1 and the high-energy composite two-dimensional image HEs1 is generated, and a difference image ES2 between the low-energy normal two-dimensional image LE2 and the high-energy composite two-dimensional image HEs2 is generated.

[0120] In (S15), stereo imaging (suction confirmation) is performed to confirm the state after the tissue has been aspirated through the needle hole. In this stereo imaging, similar to the stereo imaging in (S13) above, low-energy normal two-dimensional images LE1 and LE2 are captured at irradiation positions P1 and P2, and high-energy composite two-dimensional images HEs1 and HEs2 are generated from multiple projection images or multiple tomographic images obtained by tomosynthesis imaging based on the calculated virtual projection positions P4 and P5. Then, a difference image ES1 between the low-energy normal two-dimensional image LE1 and the high-energy composite two-dimensional image HEs1 is generated, and a difference image ES2 between the low-energy normal two-dimensional image LE2 and the high-energy composite two-dimensional image HEs2 is generated.

[0121] As described above, according to this embodiment, in CEDM biopsy, only one high-energy tomosynthesis imaging is required, which enables a reduction in radiation dose compared to the CEDM biopsy of the comparative example. Note that, although multiple imaging sessions are performed consecutively in tomosynthesis imaging, the radiation dose at this time is less than the radiation dose at the time of multiple high-energy normal imaging sessions.

[0122] Furthermore, since high-energy tomosynthesis imaging only requires one session, there is no need to capture a set of high-energy and low-energy normal 2D images, thereby reducing imaging time.

[0123] While one form of the image processing device 16 has been described above using the embodiment, the disclosed form of the image processing device 16 is merely an example, and the form of the image processing device 16 is not limited to the scope described in the embodiment. Various changes or improvements can be made to the embodiment without departing from the gist of the present disclosure, and forms incorporating such changes or improvements are also included in the technical scope of the disclosure.

[0124] In the above embodiment, an example has been described in which the control processing of the image processing device 16 is realized by software processing. However, the control processing of the image processing device 16 may be performed by hardware. In this case, the processing speed can be increased compared to when it is realized by software processing.

[0125] In the above embodiments, the term "processor" refers to a processor in a broad sense, including general-purpose processors (e.g., CPUs) and dedicated processors (e.g., GPUs: Graphics Processing Units, ASICs: Application Specific Integrated Circuits, FPGAs: Field Programmable Gate Arrays, programmable logic devices, etc.).

[0126] Furthermore, the operations of the processors in the above embodiments may not only be performed by a single processor, but may also be performed by multiple processors located at physically separate locations working together. Furthermore, the order of the operations of the processors is not limited to the order described in the above embodiments, and may be changed as appropriate.

[0127] In the above embodiment, an example has been described in which the image processing program 62A is stored in the storage unit 62. However, the storage destination of the image processing program 62A is not limited to the storage unit 62. The image processing program 62A of the present disclosure can also be provided in a form stored in a computer-readable storage medium. It may also be in the form of a computer program product including the image processing program 62A. The present disclosure can be applied to programs and program products.

[0128] For example, the image processing program 62A may be provided in a form stored on an optical disk such as a CD-ROM, a DVD-ROM, or a Blu-ray disc. The image processing program 62A may also be provided in a form stored on a portable semiconductor memory such as a USB (Universal Serial Bus) memory or a memory card. These CD-ROMs, DVD-ROMs, Blu-ray discs, USBs, and memory cards are examples of non-transitory storage media.

[0129] The following additional notes are provided regarding the above-described embodiments.

[0130] (Appendix 1) a processor; The processor: acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy higher than the first energy; calculating a virtual projection position, which is a position where the breast is virtually projected in the tomosynthesis imaging, from the position of the radiation source when the normal two-dimensional image was captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; generating a difference image between each of the plurality of ordinary two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of ordinary two-dimensional images; Image processing device. (Appendix 2) When acquiring the plurality of projection images, the processor generates the plurality of tomographic images from the plurality of projection images based on the virtual projection positions, and then generates the composite two-dimensional image from the plurality of tomographic images. 2. The image processing device according to claim 1. (Appendix 3) the processor generates the composite two-dimensional image from the plurality of tomographic images based on a projection path from the virtual projection position. 3. The image processing device according to claim 2. (Appendix 4) the processor generates the plurality of tomographic images by correcting a magnification ratio for each of the plurality of projection images around the virtual projection position; generating the composite two-dimensional image by performing parallel projection on the generated plurality of tomographic images; 3. The image processing device according to claim 2. (Appendix 5) When acquiring the plurality of tomographic images, the processor generates the composite two-dimensional image by combining the plurality of tomographic images based on the virtual projection position. 2. The image processing device according to claim 1. (Appendix 6) the processor acquires the plurality of tomographic images with the magnification ratio corrected around the virtual projection position; 2. The image processing device according to claim 1. (Appendix 7) The processor acquires the plurality of tomographic images, and if the plurality of tomographic images have not been subjected to magnification correction or the centers of magnification correction are at different positions, corrects the magnification of the plurality of tomographic images at the virtual projection position; generating the composite two-dimensional image by performing parallel projection on the corrected multiple tomographic images; 2. The image processing device according to claim 1. (Appendix 8) The normal two-dimensional image includes a plurality of two-dimensional images taken while changing the position of the radiation source. 8. The image processing device according to any one of Supplementary Note 1 to Supplementary Note 7. (Appendix 9) When the processor detects movement of the breast during the tomosynthesis imaging, the processor controls the tomosynthesis imaging to be performed again. 9. The image processing device according to any one of Supplementary Note 1 to Supplementary Note 8. (Appendix 10) When the processor detects movement of the breast during the tomosynthesis imaging, the processor corrects the movement of the breast to generate the composite two-dimensional image. 9. The image processing device according to any one of Supplementary Note 1 to Supplementary Note 8. (Appendix 11) the processor detects the movement of the breast by performing threshold processing on the difference between the normal two-dimensional image and the synthetic two-dimensional image; 11. The image processing device according to claim 9 or 10. (Appendix 12) the processor controls the tomosynthesis imaging to be performed again when a user's instruction is received after the tomosynthesis imaging. 9. The image processing device according to any one of Supplementary Note 1 to Supplementary Note 8. (Appendix 13) a processor; The processor: acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy lower than the first energy; calculating a virtual projection position, which is a position where the breast is virtually projected in the tomosynthesis imaging, from the position of the radiation source when the normal two-dimensional image was captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; generating a difference image between each of the plurality of ordinary two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of ordinary two-dimensional images; Image processing device. (Appendix 14) acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy higher than the first energy; calculating a virtual projection position, which is a position where the breast is virtually projected in the tomosynthesis imaging, from the position of the radiation source when the normal two-dimensional image was captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; A process of generating a difference image between each of the plurality of normal two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of normal two-dimensional images, A computer-implemented image processing method. (Appendix 15) acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy higher than the first energy; calculating a virtual projection position, which is a position where the breast is virtually projected in the tomosynthesis imaging, from the position of the radiation source when the normal two-dimensional image was captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; A process of generating a difference image between each of the plurality of normal two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of normal two-dimensional images, An image processing program to be executed by a computer. [Explanation of symbols]

[0131] 1. Radiography system 10 Mammography equipment 12 Console 14 PACS 16, 16A Image processing device 17 Network 191-197, 19 t Irradiation position 20 Radiation detector, 20A detection surface 24 imaging table, 24A imaging surface 26 Foundation 27 Shaft 28 Arm section 29 Radiation source 30 Compression Plate 32 Compression Unit 40, 60 Control unit 42, 50, 62 storage section 44 User I / F section 46, 74 Communication I / F section 52 Radiography images 60A CPU, 60B ROM, 60C RAM 62A Image Processing Program 70 Display section 72 Operation section 79 Bus 101 First acquisition part 102 Second acquisition part 103 Calculation Unit 104 1st generation part 105 Second generation part HE High-energy normal 2D image LE Low energy normal 2D image HEs High Energy Composite 2D Image LEs Low Energy Composite 2D Image LEp projection image ES difference image

Claims

1. a processor; The processor: acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy higher than the first energy; calculating a virtual projection position, which is a position to virtually project the breast in the tomosynthesis imaging, from a position of a radiation source when the normal two-dimensional image is captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; generating a difference image between each of the plurality of ordinary two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of ordinary two-dimensional images; Image processing device.

2. When acquiring the plurality of projection images, the processor generates the plurality of tomographic images from the plurality of projection images based on the virtual projection positions, and then generates the composite two-dimensional image from the plurality of tomographic images. The image processing device according to claim 1 .

3. the processor generates the composite two-dimensional image from the plurality of tomographic images based on a projection path from the virtual projection position. The image processing device according to claim 2 .

4. the processor generates the plurality of tomographic images by correcting a magnification ratio for each of the plurality of projection images around the virtual projection position; generating the composite two-dimensional image by performing parallel projection on the generated plurality of tomographic images; The image processing device according to claim 2 .

5. When acquiring the plurality of tomographic images, the processor generates the composite two-dimensional image by combining the plurality of tomographic images based on the virtual projection position. The image processing device according to claim 1 .

6. the processor acquires the plurality of tomographic images with the magnification ratio corrected around the virtual projection position; The image processing device according to claim 1 .

7. The processor acquires the plurality of tomographic images, and if the plurality of tomographic images have not been subjected to magnification correction or the centers of magnification correction are at different positions, corrects the magnification of the plurality of tomographic images at the virtual projection position; generating the composite two-dimensional image by performing parallel projection on the corrected tomographic images; The image processing device according to claim 1 .

8. The normal two-dimensional image includes a plurality of two-dimensional images taken while changing the position of the radiation source. The image processing device according to claim 1 .

9. When the processor detects movement of the breast during the tomosynthesis imaging, the processor controls the tomosynthesis imaging to be performed again. The image processing device according to claim 1 .

10. When the processor detects movement of the breast during the tomosynthesis imaging, the processor corrects the movement of the breast to generate the composite two-dimensional image. The image processing device according to claim 1 .

11. the processor detects the movement of the breast by performing threshold processing on the difference between the normal two-dimensional image and the synthetic two-dimensional image; The image processing device according to claim 9 or 10.

12. the processor controls the tomosynthesis imaging to be performed again when a user's instruction is received after the tomosynthesis imaging. The image processing device according to claim 1 .

13. a processor; The processor: acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy lower than the first energy; calculating a virtual projection position, which is a position to virtually project the breast in the tomosynthesis imaging, from a position of a radiation source when the normal two-dimensional image is captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; generating a difference image between each of the plurality of ordinary two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of ordinary two-dimensional images; Image processing device.

14. acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy higher than the first energy; calculating a virtual projection position, which is a position to virtually project the breast in the tomosynthesis imaging, from a position of a radiation source when the normal two-dimensional image is captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; A process of generating a difference image between each of the plurality of ordinary two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of ordinary two-dimensional images, A computer-implemented image processing method.

15. acquiring a series of multiple projection images or multiple tomographic images obtained by irradiating the breast with radiation of a first energy and performing tomosynthesis imaging; acquiring a plurality of normal two-dimensional images by irradiating the breast a plurality of times with radiation having a second energy higher than the first energy; calculating a virtual projection position, which is a position to virtually project the breast in the tomosynthesis imaging, from a position of a radiation source when the normal two-dimensional image is captured for each of the plurality of normal two-dimensional images; generating a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection positions calculated for each of the plurality of ordinary two-dimensional images; A process of generating a difference image between each of the plurality of ordinary two-dimensional images and each of the composite two-dimensional images generated for each of the plurality of ordinary two-dimensional images, An image processing program to be executed by a computer.

Images