Image processing device, medical image acquisition device, and program

Abstract

Provided is an image processing device comprising a processor. While a breast is compressed using a compression plate, the processor creates a steered transmission / reception image based on an ultrasound beam transmitted / received through the compression plate using beam steering with an ultrasound probe, and a non-steered transmission / reception image based on an ultrasound beam transmitted / received through the compression plate using non-beam steering with the ultrasound probe, and creates a compound image by using the steered transmission / reception image and the non-steered transmission / reception image created. The steered transmission / reception image is an image created by using, as main frequency components, frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasound beam transmitted for creating the steered transmission / reception image is less than or equal to half of the amplitude of the ultrasound beam. The non-steered transmission / reception image is an image created by using the frequency components as main frequency components.

Description

Image processing device, medical image acquisition device, and program

[0001] The present disclosure relates to an image processing device, a medical image acquisition device, and a program.

[0002] JP 2005-125080 A discloses a method for observing abnormalities in different types of images.

[0003] The method includes scanning an object using a first imaging system to obtain at least a first image of the object; determining coordinates of a region of interest (ROI) observable on the first image, the ROI including an abnormality; and scanning the object with a second imaging system using the coordinates of the ROI.

[0004] Furthermore, Japanese Patent Publication No. 2008-514264 discloses a method for performing ultrasound imaging diagnosis of the breast.

[0005] In this method, a breast is received between a first compression plate and a second compression plate and compressed. The breast extends from the patient's chest wall at a proximal end to the nipple at a distal end. A portion of the breast proximal to the nipple is not in contact with the second compression plate while the breast is being compressed. An ultrasound transducer array is moved along a path to scan the breast. The ultrasound transducer array is positioned adjacent to the second compression plate on an opposite side of the breast from the second plate. As the ultrasound transducer array moves along the path, image data representative of the breast is acquired. The step of acquiring image data includes steering an electron beam direction in the ultrasound transducer array to acquire image data of one or both of a portion of the breast proximal to the chest wall and a portion of the breast immediately behind the nipple corresponding to the portion of the breast not in contact with the second compression plate.

[0006] However, when an ultrasound image is taken by transmitting and receiving an ultrasound beam through a compression paddle while the breast is compressed by the compression paddle, multiple reflections occur between the front and back surfaces of the compression paddle due to differences in acoustic impedance, resulting in artifacts in the captured ultrasound image. Needless to say, these artifacts are a major obstacle to ultrasound diagnosis through interpretation of the ultrasound image.

[0007] Therefore, it is desirable to suppress this artifact as much as possible, but the techniques disclosed in the above-mentioned Japanese Patent Laid-Open No. 2005-125080 and Japanese Patent Laid-Open No. 2008-514264 do not take this artifact into consideration, and therefore there is a problem in that the artifact cannot necessarily be suppressed effectively.

[0008] The present disclosure provides an image processing device, a medical image acquisition device, and a program that can effectively suppress artifacts caused by multiple reflections of an ultrasound beam from a compression paddle when ultrasound imaging of the breast is performed via a compression paddle, compared to conventional techniques.

[0009] An image processing device of a first aspect of the present disclosure includes a processor that, when the breast is compressed by a compression plate, creates a steered transmission / reception image, which is an image of the breast using an ultrasonic beam transmitted and received through the compression plate using beam steering at a predetermined steering angle by an ultrasonic probe, and a non-steered transmission / reception image, which is an image of the breast using an ultrasonic beam transmitted and received through the compression plate using non-beam steering by the ultrasonic probe, and creates a compound image using the created steered transmission / reception image and non-steered transmission / reception image, wherein the steered transmission / reception image is an image created using frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasonic beam is half or less of the amplitude of the ultrasonic beam transmitted to create the steered transmission / reception image, and the non-steered transmission / reception image is an image created using the frequency components as the main frequency components.

[0010] Note that the term "main frequency component" here refers to a frequency component that accounts for 50% or more of the amplitude of the entire reflected wave. Furthermore, in the first aspect, the reason why frequency components in a range in which the amplitude of artifacts due to side lobes of an ultrasonic beam is half or less of the amplitude of the transmitted ultrasonic beam are used as the main frequency components is as follows: That is, if the amplitude of artifacts due to side lobes of an ultrasonic beam is within this range, the S / N (Signal-Noise) ratio is sufficiently high, and signal information of the steered transmitted / received image can be sufficiently visualized. Therefore, even when the steered transmitted / received image is combined with a non-steered transmitted / received image, it is possible to reduce the effect of artifacts due to the steered transmitted / received image and ensure clarity as an overall diagnostic image.

[0011] 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 creates the compound image in a harmonic mode or a compound harmonic mode.

[0012] An image processing device of a third aspect of the present disclosure is an image processing device of the second aspect, in which, when the processor creates a compound image in compound harmonic mode, the weight of the harmonic components is increased compared to the fundamental wave component for shallow areas including parts of multiple reflections of the ultrasound beam, and the weight of the fundamental wave component is increased as the area moves from shallow to deep.

[0013] An image processing device of a fourth aspect of the present disclosure is the image processing device of the first aspect, wherein the processor changes the setting to create a compound image when an imaging mode using a compression plate is selected.

[0014] An image processing device of a fifth aspect of the present disclosure is an image processing device of the first aspect, in which the processor changes the settings to create a compound image when an image corresponding to a compression plate is recognized in at least one of the steered transmission / reception image and the non-steered transmission / reception image.

[0015] An image processing device according to a sixth aspect of the present disclosure is the image processing device according to the first aspect, wherein the processor changes the setting to create a compound image when compression by the compression plates is completed.

[0016] An image processing device of a seventh aspect of the present disclosure is an image processing device of the first aspect, in which a processor creates a compound image by changing the weighting ratio of the steered transmission / reception image and the non-steered transmission / reception image depending on the depth of multiple reflections of the ultrasonic beam.

[0017] An image processing device of an eighth aspect of the present disclosure is an image processing device of the first aspect, in which the processor does not use reflected waves corresponding to the area between the front surface of the compression plate, which is the surface opposite the breast side, and the back surface, which is the surface on the breast side, but instead increases the weight of the steered transmitted / received image over the weight of the non-steered transmitted / received image from the back surface of the compression plate up to the depth of multiple reflections of the ultrasound beam, and increases the weight of the non-steered transmitted / received image as the depth increases, thereby creating a compound image.

[0018] An image processing device of a ninth aspect of the present disclosure is the image processing device of the first aspect, wherein the sound speed of the ultrasonic beam is set to a sound speed between the sound speed of the breast and the sound speed of the compression paddle.

[0019] An image processing device according to a tenth aspect of the present disclosure is the image processing device according to the first aspect, wherein the main frequency components are frequency components of 8 MHz or less, and the steering angle is an angle of 20 degrees or less.

[0020] An image processing device according to an eleventh aspect of the present disclosure is the image processing device according to the first aspect, wherein the main frequency components are frequency components of 9 MHz or less, and the steering angle is an angle of 15 degrees or less.

[0021] An image processing device of a twelfth aspect of the present disclosure is the image processing device of the first aspect, wherein the main frequency components are frequency components of 11 MHz or less, and the steering angle is an angle of 10 degrees or less.

[0022] A medical image acquisition device according to a thirteenth aspect of the present disclosure includes the image processing device according to the first aspect, and a display unit that displays a compound image created by the image processing device.

[0023] Furthermore, a fourteenth aspect of the present disclosure is a program that causes a computer to execute a process of creating, when the breast is compressed by a compression plate, a steered transmission / reception image, which is an image of the breast using an ultrasonic beam transmitted and received via the compression plate using beam steering at a predetermined steering angle by an ultrasonic probe, and a non-steered transmission / reception image, which is an image of the breast using an ultrasonic beam transmitted and received via the compression plate using non-beam steering by an ultrasonic probe, and creating a compound image using the created steered transmission / reception image and non-steered transmission / reception image, wherein the steered transmission / reception image is an image created using frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasonic beam is half or less of the amplitude of the ultrasonic beam transmitted to create the steered transmission / reception image, and the non-steered transmission / reception image is an image created using these frequency components as the main frequency components.

[0024] According to the present disclosure, when ultrasonic imaging of a breast is performed via a compression paddle, artifacts caused by multiple reflections of an ultrasonic beam from the compression paddle can be effectively suppressed compared to conventional techniques.

[0025] 1 is a diagram showing an example of a schematic configuration of an image generation system according to an embodiment; FIG. 2 is a side view showing an example of the appearance of an image generation device according to an embodiment; FIG. 3 is a three-view diagram showing an example of a schematic configuration of a compression member according to an embodiment; FIG. 4 is a block diagram showing an example of a hardware configuration of a console according to an embodiment; FIG. 5 is a block diagram showing an example of a functional configuration of a console according to an embodiment; FIG. 6 is a graph used to explain main frequency components and steering angles according to an embodiment, and is a graph showing the directivity of elements in the specifications of an ultrasound probe for breast use; FIG. 7 is a diagram showing an example of harmonic components of an ultrasound image according to an embodiment; FIG. 8 is a diagram showing an example of a fundamental wave component of an ultrasound image according to an embodiment; FIG. 9 is a flowchart showing an example of image processing according to an embodiment; FIG. 10 is a diagram showing an example of an initial screen according to an embodiment; FIG. 11 is a schematic diagram used to explain a method for creating a compound image according to an embodiment; FIG. 12 is a diagram showing an example of a compound image display screen according to an embodiment; FIG. 13 is a diagram showing another example of a compound image display screen according to an embodiment;

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0027] First, the configuration of an image generation system 1 to which the technology of the present disclosure is applied will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of a schematic configuration of the image generation system 1 according to this embodiment.

[0028] 1, the image generation system 1 includes an image generation device 10 and a console 50. The image generation device 10 and the console 50, and the console 50 and an external RIS (Radiology Information System) 6 are configured to be connectable via a wired or wireless network.

[0029] In the image generating system 1 according to this embodiment, the console 50 acquires an imaging order and the like from the RIS 6 and controls the image generating device 10 in accordance with the imaging order and user instructions, etc. The image generating device 10 captures a radiological image by irradiating radiation R onto a breast compressed between an imaging table 16 (described later) and a compression member 40 serving as a compression plate in the technology of the present disclosure. The image generating device 10 also acquires an ultrasound image of the compressed breast via the compression member 40. The image generating system 1 corresponds to the medical image acquisition device in the technology of the present disclosure.

[0030] Next, a schematic configuration of the image generating device 10 according to this embodiment will be described with reference to FIG. 2. FIG. 2 is a side view showing an example of the appearance of the image generating device 10 according to this embodiment, as viewed from the right side of the subject. As shown in FIG. 2, the image generating device 10 includes a radiation source 17R, a radiation detector 28, an imaging table 16 disposed between the radiation source 17R and the radiation detector 28, a compression member 40 that compresses the breast between the imaging table 16, and an ultrasound probe 30. In the image generating device 10, a user such as a doctor or technician positions the subject's breast on an imaging surface 16A of the imaging table 16.

[0031] The image generating device 10 includes an arm unit 12, a base 14, and a shaft unit 15. The arm unit 12 is held by the base 14 so as to be movable in the vertical direction (Z direction). The shaft unit 15 connects the arm unit 12 to the base 14. The arm unit 12 is rotatable relative to the base 14 around the shaft unit 15 as a rotation axis. Furthermore, the arm unit 12 may have an upper portion including a radiation irradiation unit 17 and a lower portion including an imaging table 16 that are rotatable relative to the base 14 around the shaft unit 15 as a rotation axis, separately.

[0032] The arm 12 includes a radiation irradiator 17 and an imaging table 16. The radiation irradiator 17 includes a radiation source 17R and is configured to be able to change the irradiation field of radiation (e.g., X-rays) irradiated from the radiation source 17R. The irradiation field may be changed, for example, by a user operating the operation unit 26, or may be changed by the control unit 20 depending on the type of the attached compression member 40.

[0033] The imaging stand 16 includes a control unit 20, a storage unit 22, an I / F (Interface) unit 24, an operation unit 26, and a radiation detector 28. The control unit 20 controls the overall operation of the image generation device 10 in accordance with the control of the console 50. The control unit 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. (not shown). The ROM stores various programs in advance, including programs executed by the CPU for controlling the generation of radiographic images and ultrasound images. The RAM temporarily stores various data.

[0034] Data of radiographic images and ultrasound images, various other information, etc. are stored in the storage unit 22. The storage unit 22 is realized by a storage medium such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory.

[0035] The I / F unit 24 communicates various types of information with the console 50 via wired or wireless communication. Specifically, the I / F unit 24 receives information related to the control of the image generation device 10 from the console 50. The I / F unit 24 also transmits radiographic image and ultrasound image data to the console 50.

[0036] The operation unit 26 is a part provided on the imaging stand 16 or the like that can be operated by the user with the hands or feet, and is, for example, a switch, a button, a touch panel, or the like.

[0037] The radiation detector 28 is disposed inside the imaging table 16, detects radiation R that has passed through the breast and the imaging table 16, generates a radiographic image based on the detected radiation R, and outputs image data representing the generated radiographic image. The type of radiation detector 28 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.

[0038] A probe unit 38 and a compression unit 48 are connected to the arm 12. A support part 36 that detachably supports the ultrasonic probe 30 is attached to the probe unit 38. A drive part (not shown) provided in the probe unit 38 moves the support part 36 (ultrasonic probe 30) in the vertical and horizontal directions (X direction, Y direction, and Z direction). The support part 36 is preferably made of a material that transmits radiation R.

[0039] The ultrasonic probe 30 is used to obtain an ultrasonic image of the breast compressed by the compression member 40, and is positioned between the radiation source 17R and the compression member 40, irradiating ultrasonic waves onto the breast via the compression member 40 and receiving reflected waves from the breast.

[0040] Specifically, the ultrasonic probe 30 includes an ultrasonic transducer array. The ultrasonic transducer array is configured with a plurality of ultrasonic transducers arranged one-dimensionally or two-dimensionally. The ultrasonic transducer may be formed by forming electrodes on both ends of a piezoelectric body, such as a piezoelectric ceramic typified by lead zirconate titanate (PZT: Lead Zirconate Titanate), a piezoelectric single crystal typified by lead magnesium niobate-lead titanate (PMN-PT: Lead Magnesium Niobate-Lead Titanate), or a polymer piezoelectric element typified by polyvinylidene difluoride (PVDF). Alternatively, the ultrasonic transducer may be a capacitive micro-machined ultrasonic transducer (CMUT).

[0041] Furthermore, the image generating device 10 may be configured so that multiple different types of ultrasound probes 30 can be attached interchangeably. Specifically, ultrasound probes 30 with different performance and dimensions may be attached depending on the subject's physique (e.g., breast size), breast tissue composition (e.g., fat mass and mammary gland mass), and type of imaging (e.g., magnification imaging and spot imaging). For example, a linear probe with a center frequency of approximately 7.5 MHz (for superficial imaging, etc.), a convex probe with a center frequency of approximately 3.5 MHz (for abdominal imaging, etc.), and a sector probe with a center frequency of approximately 2.5 MHz (for cardiac imaging, etc.) may be used.

[0042] A support part 46 that supports the compression member 40 is detachably attached to the compression unit 48. A drive part (not shown) provided in the compression unit 48 moves the support part 46 (compression member 40) in the up-down direction (Z direction).

[0043] The compression member 40 is disposed between the radiation source 17R and the imaging table 16, and compresses the breast by sandwiching the breast between the radiation source 17R and the imaging table 16. Figure 3 shows three views of an example of the compression member 40. The three views in Figure 3 include a top view of the compression member 40 seen from above (the radiation irradiation unit 17 side), a side view seen from the subject side, and a side view seen from the right side of the subject. As shown in Figure 3, the compression member 40 includes a compression portion 42 and a support portion 46.

[0044] The support portion 46 includes an attachment portion 47 and an arm 49. The attachment portion 47 attaches the compression member 40 to the image generation device 10, specifically to a drive portion of a compression unit 48. The arm 49 supports the compression portion 42.

[0045] The compression unit 42 has a generally flat bottom 43 surrounded by walls 44 of generally uniform height, and has a concave cross-sectional shape. The compression unit 42 is preferably made of an optically transparent or translucent material so that positioning and the compression state can be confirmed during breast compression. The compression unit 42 is also preferably made of a material that is highly transmissive to radiation R and ultrasound. The compression unit 42 is also preferably made of a material that has excellent strength, such as drop strength and compression strength.

[0046] Examples of such materials that can be used include resins such as polymethylpentene (PMP), polycarbonate (PC), acrylic, polypropylene (PP), and polyethylene terephthalate (PET). Polymethylpentene, in particular, has an acoustic impedance that affects the transmittance and reflectance of ultrasound waves, which is closer to that of the human body (breast) than other materials, thereby reducing the amount of noise imparted to ultrasound images. Therefore, polymethylpentene is a suitable material for the compression portion 42.

[0047] Furthermore, the image generating device 10 may be configured to allow multiple different types of compression members 40 to be attached interchangeably. Specifically, compression members 40 of different materials, sizes, and shapes may be attached depending on the subject's physique (e.g., breast size), breast tissue composition (e.g., fat mass and mammary gland mass), and type of imaging (e.g., magnification imaging and spot imaging). For example, a compression member according to the size of the breast, a compression member for axillary imaging, a compression member for magnification imaging, and a compression member for so-called spot imaging, which captures a radiographic image of only the area where a lesion is present, may be used. In other words, the compression member 40 is not limited to one that compresses the entire breast, but may also be one that is smaller than the breast and compresses only a portion of the breast.

[0048] FIG. 4 shows a three-view diagram of a compression member 40S for small breasts, an example of a different configuration from the compression member 40 of FIG. 3 . The three-view diagram of FIG. 4 includes a top view of the compression member 40S from above (the radiation irradiation unit 17 side), a side view from the subject side, and a side view from the right side of the subject. Like the compression member 40 of FIG. 3 , the compression member 40S includes a compression section 42 and a support section 46. The bottom section 43 of the compression member 40S is not flat, but is higher on the attachment section 47 side than on the chest wall side (the side farther from the attachment section 47). Furthermore, the wall section 44 does not have a uniform height, with the height of a portion of the wall side being lower than the height of the remaining portion. This shape allows the compression member 40S to easily position and compress even small breasts.

[0049] In this way, at least one of the compression member 40 for compressing the breast and the ultrasound probe 30 for acquiring ultrasound images can be detachable in the image generating device 10. In this case, the image generating device 10 may detect the type of compression member 40 and ultrasound probe 30 that are attached.

[0050] For example, a plurality of pins, the arrangement of which varies depending on the type of compression member 40, may be provided on the attachment portion 47 of the compression member 40 as identification information, and the identification information may be read by a sensor (e.g., a photointerrupter) that is capable of detecting the arrangement of the pins and that is provided on the compression unit 48. Alternatively, for example, a marker (e.g., a barcode or a two-dimensional code) that corresponds to the type of compression member 40 may be provided at an arbitrary position on the compression member 40 as identification information, and the identification information may be read by a sensor (e.g., a charge coupled device (CCD) sensor) that can detect the marker.

[0051] Alternatively, for example, a radio frequency identification (RFID) tag having identification information corresponding to the type of compression member 40 may be provided at any position on the compression member 40, and the identification information may be read by an RFID reader capable of reading the RFID tag. Alternatively, for example, the weight of each type of compression member 40 may be associated with the identification information and stored in advance in the storage unit 22, the weight of the attached compression member 40 may be measured by a sensor capable of detecting weight, and the identification information (type of compression member 40) may be determined based on the measured value.

[0052] Similarly, the type of the attached ultrasonic probe 30 may be identified according to, for example, a pin, a marker, an RFID tag, weight, or the like.

[0053] The image generating device 10 also detects the compression pressure applied to the breast by the compression members 40. For example, when the compression members 40 compress the breast, a reaction force equal to the compression pressure is applied to the drive unit of the compression members 40. Utilizing this, a strain gauge (e.g., a load cell) that detects the reaction force applied to the drive unit may be provided in the compression unit 48, and the reaction force detected by the strain gauge may be detected as the compression pressure. Alternatively, for example, a semiconductor pressure sensor, a capacitance pressure sensor, or the like may be used to detect the compression pressure. Alternatively, for example, various sensors that detect the compression pressure may be provided on the compression member 40 side instead of on the compression unit 48 side.

[0054] The image generating device 10 also detects the distance (hereinafter referred to as "compression thickness") between the imaging surface 16A of the imaging table 16 and the contact surface 43B of the bottom 43 of the compression portion 42 of the compression member 40 when the compression member 40 is compressing the breast. For example, the compression thickness may be detected using a distance sensor using laser light, ultrasound, or the like. Alternatively, the compression thickness may be detected from the vertical position of the support portion 46.

[0055] The top surface 43A and / or the contact surface 43B of the bottom 43 of the compression member 40 may be coated with a gel or liquid ultrasonically transmissive medium. Examples of such a medium include a known ultrasound examination jelly having an acoustic impedance similar to that of the human body (breast). That is, the image generating device 10 may acquire an ultrasound image of a breast compressed by the compression member 40 coated with a gel or liquid ultrasonically transmissive medium via the compression member 40. In this case, air can be prevented from entering the interface between the ultrasound emitting surface of the ultrasonic probe 30 and the top surface 43A and / or the interface between the contact surface 43B and the breast. This reduces the difference in acoustic impedance at each interface, thereby reducing the amount of noise in the ultrasound image.

[0056] Furthermore, the method of breast imaging using the image generating device 10 is not particularly limited. For example, craniocaudal (CC) imaging, mesolateral oblique (MLO) imaging, magnified imaging that captures a portion of the breast, and spot imaging may be used. CC imaging is a method of imaging the compressed breast by sandwiching the breast between the imaging table 16 and the compression member 40 in the vertical direction (Z direction). MLO imaging is a method of imaging the compressed breast, including the axillary region, by sandwiching the breast between the imaging table 16 and the compression member 40 while tilting the arm unit 12 so that the rotation angle relative to the base 14 is between 45 degrees and 90 degrees.

[0057] Furthermore, for example, the image generating device 10 may be one that performs tomosynthesis imaging. In tomosynthesis imaging, radiation R is irradiated from the radiation source 17R toward the breast from a plurality of irradiation positions each having a different irradiation angle, and a plurality of radiographic images of the breast are captured. That is, in tomosynthesis imaging, the angles of the imaging table 16, the compression member 40, the breast, etc. are kept fixed, and imaging is performed by changing the rotation angle of the radiation emitting unit 17 relative to the base 14.

[0058] Furthermore, the image generating device 10 may be capable of positioning the subject's breasts not only when the subject is standing (standing position), but also when the subject is sitting in a chair, wheelchair, etc. (sitting position).

[0059] The console 50 sets an upper limit of the compression pressure that the compression members 40 apply to the breast depending on the type of compression members 40 attached to the image generating device 10. The console 50 also controls the image generating device 10 so that a radiographic image is acquired in accordance with the imaging order acquired from the RIS 6 and instructions from the user. The console 50 also controls the position of the ultrasound probe 30 so that an ultrasound image can be acquired in accordance with the position of the region of interest included in the radiographic image acquired by the image generating device 10.

[0060] As described above, the image generating device 10 according to this embodiment has the probe unit 38 provided between the radiation emitting unit 17 and the compression unit 48, and can acquire both radiographic images and ultrasound images while the breast is compressed by the compression members 40. This facilitates the alignment of these images, and can improve the ability to differentiate and diagnose lesions by, for example, displaying both images superimposed on each other.

[0061] Next, the console 50 according to this embodiment will be described.

[0062] First, an example of the hardware configuration of the console 50 will be described with reference to Fig. 5. As shown in Fig. 5, the console 50 includes a CPU 51, a non-volatile storage unit 52, and a memory 53 serving as a temporary storage area. The console 50 also includes a display 54 such as a liquid crystal display, an operation unit 55 such as a touch panel, a keyboard, and a mouse, and an I / F unit 56. The I / F unit 56 communicates with the image generation device 10, the RIS 6, and other external devices via wired or wireless communication. The CPU 51, the storage unit 52, the memory 53, the display 54, the operation unit 55, and the I / F unit 56 are connected via a bus 58 such as a system bus and a control bus so as to be able to exchange various information with each other.

[0063] The storage unit 52 is realized by a storage medium such as a HDD, SSD, or flash memory. An image processing program 52A is stored in the storage unit 52. The CPU 51 reads the image processing program 52A from the storage unit 52, loads it into the memory 53, and executes the loaded image processing program 52A. The console 50 can be, for example, a personal computer, a server computer, a smartphone, a tablet terminal, a wearable terminal, or the like, as appropriate.

[0064] Furthermore, the storage unit 52 stores image data of radiographic images and ultrasound images created from data acquired by the image generating device 10, as well as various other information. The image data of radiographic images and ultrasound images may be stored in association with at least one of an imaging order and imaging information. The imaging information may be, for example, at least one of subject information and imaging type included in the imaging order, photographer information indicating the photographer who performed the imaging (e.g., a user such as a doctor or technician), and date and time information indicating the date and time when the imaging was performed.

[0065] Next, an example of the functional configuration of the console 50 will be described with reference to Fig. 6. As shown in Fig. 6, the console 50 includes a first creation unit 60, a second creation unit 62, and a display control unit 64. The CPU 51 executes the image processing program 52A, causing the CPU 51 to function as the first creation unit 60, the second creation unit 62, and the display control unit 64.

[0066] The first creation unit 60 according to this embodiment creates, with the breast compressed by the compression member 40, steered transmission and reception images, which are images of the breast using ultrasonic beams transmitted and received via the compression member 40 using beam steering at a predetermined steering angle by the ultrasound probe 30, and non-steered transmission and reception images, which are images of the breast using ultrasonic beams transmitted and received via the compression member 40 using non-beam steering by the ultrasound probe 30. The second creation unit 62 according to this embodiment then creates a compound image using the steered transmission and reception images and non-steered transmission and reception images created by the first creation unit 60. Note that the steering angle here refers to the angle with respect to the emission direction of the ultrasonic beam from the ultrasound probe 30.

[0067] In this embodiment, the steering transmission / reception image is an image created with frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasonic beam is half or less of the amplitude of the ultrasonic beam transmitted to create the steering transmission / reception image as the main frequency component, and the non-steer transmission / reception image is an image created with the same frequency components as the main frequency component.

[0068] The principle of the technology of the present disclosure will now be described with reference to Fig. 7. Fig. 7 is a graph illustrating the main frequency components and steering angles according to this embodiment, and is a graph showing the directivity of elements in the specifications of an ultrasound probe for the mammary gland.

[0069] The side lobe emission angle θm (hereinafter referred to as the "side lobe angle") in the case of beam steering is expressed by the following equation (1): where θs represents the steering angle, p represents the pitch of the elements (ultrasonic transducers) of the ultrasonic probe 30, and λ represents the wavelength of the ultrasonic beam. Note that the angle in the side lobe angle here also means the angle with respect to the emission direction of the ultrasonic beam from the ultrasonic probe 30.

[0070]

[0071] Here, the specifications of ultrasound probes generally used for diagnosing mammary glands are, for example, as described on the Internet at <URL: https: / / www.ndk.com / jp / products / ultrasound / probe / linear_probe / #020>, with the element pitch p often being around 0.2 mm and the frequency often being around 5 to 15 MHz.

[0072] On the other hand, the amplitude of an ultrasonic beam generally decreases when the transmission and reception direction deviates from the perpendicular direction of the element. As an example, as shown in Figure 7, the amplitude of a sound wave transmitted in a 20-degree direction is twice that of a sound wave transmitted in a 37-degree direction (a difference of 6 dB). Similarly, the amplitude of a sound wave transmitted in a 15-degree direction is twice that of a sound wave transmitted in a 33-degree direction, and the amplitude of a sound wave transmitted in a 10-degree direction is twice that of a sound wave transmitted in a 30-degree direction.

[0073] Therefore, the developers of the technology disclosed herein used Equation (1) to determine the relationship between each frequency component and the steering angle θs and side lobe angle θm when the pitch p was 0.2 mm and the transmission frequency f of the ultrasonic beam was in the range of 5 MHz to 15 MHz, and summarized the results as shown in Tables 1 to 3. Table 1 is a table for determining the main frequency component at which the amplitude of the side lobe artifact is less than half the amplitude of the ultrasonic beam when transmitted with a steering angle θs of 20 degrees or less. Table 2 is a table for determining the main frequency component at which the amplitude of the side lobe artifact is less than half the amplitude of the ultrasonic beam when transmitted with a steering angle θs of 15 degrees or less. Table 3 is a table for determining the main frequency component at which the amplitude of the side lobe artifact is less than half the amplitude of the ultrasonic beam when transmitted with a steering angle θs of 10 degrees or less.

[0074]

[0075]

[0076]

[0077] Then, the developers of the technology disclosed herein used the values ​​(37 degrees, 33 degrees, and 30 degrees) described with reference to FIG. 7 as thresholds to determine the transmission frequency of the ultrasonic beam at which the amplitude of the side lobe artifact is equal to or less than half the amplitude of the transmitted ultrasonic beam. This transmission frequency corresponds to the masked portion in Tables 1 to 3, and the frequency is 8 MHz or less when the steering angle θs is 20 degrees or less. Similarly, the frequency is 9 MHz or less when the steering angle θs is 15 degrees or less, and the frequency is 11 MHz or less when the steering angle θs is 10 degrees or less.

[0078] Therefore, in the console 50 according to this embodiment, a frequency component of 8 MHz or less is applied as the main frequency component, and a steering angle θs of 20 degrees or less is applied. However, this is not restrictive, and a frequency component of 9 MHz or less may be applied as the main frequency component, and a steering angle θs of 15 degrees or less may be applied. Furthermore, a frequency component of 11 MHz or less may be applied as the main frequency component, and a steering angle θs of 10 degrees or less may be applied. By applying any of the above combinations of the main frequency component and the steering angle θs, the influence of multiple reflections due to side lobes can be suppressed, and as a result, artifacts due to multiple reflections of the ultrasound beam at the compression member 40 can be effectively suppressed.

[0079] Moreover, the second creating unit 62 according to this embodiment creates the compound image in a harmonic mode or a compound harmonic mode.

[0080] The harmonic mode is a mode that creates images using only harmonic components, and although THI (Tissue Harmonic Imaging) mode and CHI (Contrast Harmonic Imaging) mode are applicable, the present embodiment applies the THI mode.

[0081] On the other hand, the compound harmonic mode is a mode in which images are created using both harmonic components and fundamental components, and then both images are weighted and added together to create an image.

[0082] When the second creation unit 62 according to this embodiment creates a compound image in compound harmonic mode, it increases the weight of the harmonic components compared to the fundamental wave component for shallow areas including areas of multiple reflection of the ultrasonic beam, and increases the weight of the fundamental wave component as it moves from shallow to deep areas.

[0083] FIG. 8 shows an example of harmonic components of an ultrasound image according to this embodiment, and FIG. 9 shows an example of fundamental components of an ultrasound image according to this embodiment.

[0084] As shown in Figures 8 and 9, harmonic components are attenuated throughout the image, but artifacts are few. In contrast, fundamental components are easily visible in deep areas but difficult to see in shallow areas. Therefore, by using the compound harmonic mode to increase the weight of the fundamental wave in deep areas where harmonic components are generally attenuated, high-resolution images can be obtained in shallow areas, ensuring penetration (depth reach) of deep areas.

[0085] Methods for imaging in compound harmonic mode include a method in which imaging is performed by performing two transmissions and receptions, one for the harmonic component and one for the fundamental component, and a method in which imaging is performed by detecting and imaging a wideband pulse at the frequency of the harmonic component, and the other method in which imaging is performed by detecting and imaging at the frequency of the fundamental component and performing weighted addition to perform imaging with only one transmission and reception.

[0086] On the other hand, the second creation unit 62 according to the present embodiment changes the setting to create a compound image when the compression by the compression member 40 has ended. This makes it possible to avoid unnecessary ultrasound imaging before the compression by the compression member 40 has ended.

[0087] Furthermore, the second creation unit 62 according to this embodiment creates a compound image by changing the weight ratio between the steered transmitted and received images and the non-steered transmitted and received images according to the depth of multiple reflections of the ultrasonic beam. In particular, the second creation unit 62 according to this embodiment does not use reflected waves corresponding to the surface of the compression member 40 opposite the breast side, i.e., the upper surface 43A, and the back surface of the compression member 40 facing the breast, i.e., the contact surface 43B, but creates a compound image by increasing the weight of the steered transmitted and received images compared to the weight of the non-steered transmitted and received images from the back surface of the compression member 40 up to the depth of multiple reflections of the ultrasonic beam, and increasing the weight of the non-steered transmitted and received images as the depth increases.

[0088] Furthermore, in this embodiment, the sound speed of the ultrasonic beam is set to a sound speed (1490 m / s in this embodiment) between the sound speed in the breast (for example, 1450 m / s set when a preset for the mammary gland is selected) and the sound speed in the compression member 40 (for example, 2097 m / s).

[0089] Next, the operation of the console 50 according to this embodiment will be described with reference to FIG. 10 . In the console 50, the CPU 51 executes the image processing program 52A, thereby performing the image processing shown in FIG. 10 . This image processing is performed, for example, when a user issues an instruction to start the processing via the operation unit 55. Here, a case will be described in which the console 50 acquires information indicating the compression pressure and compression thickness (hereinafter referred to as "setting information") used when capturing a radiographic image of the breast from the RIS. Here, a case will be described in which a user, such as a doctor or technician, positions the subject's breast (hereinafter referred to as the "target breast") on the imaging surface 16A of the imaging table 16, and an appropriate ultrasound probe 30 is attached to the probe unit 38.

[0090] In step S10, the CPU 51 controls the display 54 to display an initial screen having a predetermined configuration, and in step S12, the CPU 51 waits until predetermined information is input.

[0091] An example of an initial screen according to this embodiment is shown in Fig. 11. As shown in Fig. 11, the initial screen according to this embodiment displays a message prompting the user to specify an image generation mode for an ultrasound image. Furthermore, the initial screen according to this embodiment displays two image generation modes, the harmonic mode and the compound harmonic mode, each of which can be specified.

[0092] 11 is displayed on the display 54, the user selects one of the image generation modes via the operation unit 55. When the user selects one of the image generation modes, the determination in step S12 is affirmative, and the process proceeds to step S14.

[0093] In step S14, the CPU 51 instructs the image generating device 10 to start compressing the target breast with the compression members 40 by instructing the image generating device 10 to set the compression pressure and compression thickness by the compression members 40 to the values ​​indicated in the setting information. In step S16, the CPU 51 waits until compression of the target breast by the compression members 40 is completed (the compression pressure and compression thickness reach the values ​​indicated in the setting information). Through the above processing, the state of compression of the target breast by the compression members 40 becomes the state at the time of capturing each image.

[0094] In step S18, the CPU 51 controls the image generating device 10 to capture a radiographic image. Through this control, the image generating device 10 captures a radiographic image of the target breast compressed by the compression member 40 in the state indicated by the setting information, and generates image data representing the radiographic image obtained by the radiographic image capture. As described above, various information required for capturing the radiographic image at this time is obtained from the RIS.

[0095] In step S20, the CPU 51 controls the image generation device 10 to capture steering transmitted / received images and non-steered transmitted / received images under conditions corresponding to the mode specified by the user on the initial screen. In response to this control, the image generation device 10 generates steering transmitted / received images and non-steered transmitted / received images and transmits them to the console 50. As described above, at this time, an angle of 20 degrees or less is applied as the steering angle θs when capturing images to generate steering transmitted / received images.

[0096] In step S22, the CPU 51 creates a compound image using the steered transmitted and received images and the non-steered transmitted and received images received from the image generating device 10. Fig. 12 is a schematic diagram illustrating a compound image creation method according to this embodiment.

[0097] As shown in Figure 12, in the image processing according to this embodiment, a compound image is created by performing a weighted averaging of a steered transmitted / received image with a steering angle of 15 degrees left and 15 degrees right (indicated as "steered" in Figure 12) and a non-steered transmitted / received image (indicated as "no steering" in Figure 12) as described above.

[0098] In step S24, the CPU 51 controls the display 54 to display a compound image display screen having a predetermined configuration using the created compound image, and in step S26, the CPU 51 waits until predetermined information is input.

[0099] An example of a compound image display screen according to this embodiment is shown in Fig. 13. As shown in Fig. 13, the compound image display screen according to this embodiment displays the sound speed of the ultrasonic beam emitted from the ultrasonic probe 30 (1490 m / s in this embodiment) and also displays the created compound image.

[0100] Other examples of the compound image display screen according to this embodiment are shown in Figures 14 and 15. Note that Figure 14 displays a compound image when the sound velocity of the ultrasonic beam is set to 1450 m / s, and Figure 15 displays a compound image when the sound velocity of the ultrasonic beam is set to 1600 m / s, with the other conditions being the same as those shown in Figure 13.

[0101] The compound images shown in Figures 13 to 15 were taken using a phantom in which multiple pins are arranged in a regular pattern to determine the resolution of the image created by the imaging, and each pin should have a perfect circular shape when viewed from the front.

[0102] Comparing the compound images shown in Figures 13 to 15, it can be seen that the compound images shown in Figures 14 and 15 have lower resolution and the pin shapes extend more horizontally the deeper they are, compared to the compound image shown in Figure 13 (a compound image created with the sound speed of the ultrasound beam set to a sound speed between the sound speed of the breast and the sound speed of the compression member 40).

[0103] In this way, by setting the sound velocity of the ultrasonic beam to a value between the sound velocity of the breast and the sound velocity of the compression member 40, the resolution of the compound image can be improved compared to other cases.

[0104] 13 is displayed on the display 54, the user interprets the displayed compound image and then presses the end button 54A via the operation unit 55. When the end button 54A is pressed by the user, a positive determination is made in step S26, and the image processing ends.

[0105] As described above, the console 50 as an image processing device according to this embodiment creates, when the breast is compressed by the compression plate, a steered transmission / reception image, which is an image of the breast using ultrasonic beams transmitted and received through the compression plate by beam steering at a predetermined steering angle using the ultrasonic probe, and a non-steered transmission / reception image, which is an image of the breast using ultrasonic beams transmitted and received through the compression plate by non-beam steering using the ultrasonic probe, and creates a compound image using the created steered transmission / reception image and non-steered transmission / reception image.

[0106] Here, the console 50 according to the present embodiment applies, as the steered transmit / receive image, an image created with frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasonic beam is half or less of the amplitude of the ultrasonic beam transmitted to create the steered transmit / receive image as the main frequency component, and applies, as the non-steered transmit / receive image, an image created with the same frequency components as the main frequency component. Therefore, compared to conventional techniques, artifacts due to multiple reflections of the ultrasonic beam from the compression paddle can be effectively suppressed when ultrasonically imaging the breast via the compression paddle.

[0107] Furthermore, according to the console 50 of this embodiment, the compound image is created in the harmonic mode or the compound harmonic mode. Therefore, when the compound image is created in the harmonic mode or the compound harmonic mode, artifacts due to multiple reflections can be suppressed.

[0108] Furthermore, according to the console 50 of this embodiment, when a compound image is created in the compound harmonic mode, the weight of the harmonic components is increased compared to the fundamental component in shallow areas including areas where the ultrasonic beam is multiple-reflected, and the weight of the fundamental component is increased as the depth increases from shallow to deep areas. Therefore, a high-resolution image can be obtained in shallow areas, and penetration of deep areas can be ensured, resulting in a high-quality compound image.

[0109] Furthermore, the console 50 according to this embodiment changes the setting to create a compound image when compression by the compression paddles is completed, thereby avoiding unnecessary ultrasound imaging before compression by the compression paddles is completed.

[0110] Furthermore, the console 50 according to this embodiment creates a compound image by changing the weighting ratio between the steered transmitted / received image and the non-steered transmitted / received image according to the depth of the multiple reflections of the ultrasonic beam, thereby reducing the influence of multiple reflections and improving the overall image quality of the compound image (resolution, reduction of artifacts other than multiple reflections, etc.).

[0111] Furthermore, with the console 50 according to this embodiment, the reflected waves corresponding to the area between the front surface of the compression paddle opposite the breast side and the back surface of the compression paddle on the breast side are not used, and the weight of the steered transmitted / received image is made greater than the weight of the non-steered transmitted / received image from the back surface of the compression paddle up to the depth of the multiple reflections of the ultrasound beam, and the weight of the non-steered transmitted / received image is made greater as the depth increases, thereby more effectively reducing the effects of multiple reflections and improving the overall image quality of the compound image.

[0112] Furthermore, according to the console 50 of this embodiment, the sound velocity of the ultrasound beam is set to a value between the sound velocity of the breast and the sound velocity of the compression paddle, thereby improving the resolution of the compound image.

[0113] In the above embodiment, the CPU 51 provided in the console 50 is used as the processor of the technology of the present disclosure, but the present disclosure is not limited to this. For example, the CPU of the control unit 20 provided in the image generating device 10 may be used as the processor of the technology of the present disclosure.

[0114] In the above embodiment, the setting is changed to create a compound image when compression by the compression member 40 ends, but the present invention is not limited to this. For example, the setting may be changed to create a compound image when an imaging mode using the compression member 40 is selected. Furthermore, for example, the setting may be changed to create a compound image when an image corresponding to the compression member 40 is recognized in at least one of the steered transmitted / received image and the non-steered transmitted / received image.

[0115] That is, the image generating device 10 can capture radiographic images and ultrasound images, but may be provided with two modes for capturing ultrasound images: one using the compression member 40 and one not using the compression member 40. In this case, when performing ultrasound imaging in the latter imaging mode, multiple reflections caused by the compression member 40 do not occur, and therefore it is not necessary to create the compound image according to the above embodiment. Therefore, in this case, unnecessary processing can be avoided by creating the compound image according to the above embodiment only when the imaging mode using the compression member 40 is selected.

[0116] In addition, as a method for recognizing an image corresponding to the compression member 40 in at least one of the steering transmission / reception image and the non-steering transmission / reception image, a method using pattern matching or an image extraction model that has been machine-learned in advance can be applied.

[0117] In the above embodiment, the following various processors can be used as the hardware structure of processing units that perform various processes, such as the first creation unit 60, the second creation unit 62, and the display control unit 64. As described above, the various processors include a CPU, which is a general-purpose processor that executes software (programs) and functions as various processing units, as well as dedicated electrical circuits, such 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), and an ASIC (Application Specific Integrated Circuit), which is a processor having a circuit configuration designed specifically for performing specific processes.

[0118] 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.

[0119] Examples of configuring multiple processing units with a single processor include: first, 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 typified by computers such as client and server; second, a form in which a processor is used to realize the functions of an entire system including multiple processing units with a single IC (Integrated Circuit) chip, as typified by systems on chips (SoCs); and thus, various processing units are configured using one or more of the above-mentioned various processors as a hardware structure.

[0120] Furthermore, more specifically, the hardware structure of these various processors can be an electric circuit that combines circuit elements such as semiconductor elements.

[0121] In the above embodiment, the image processing program 52A is pre-stored (installed) in the storage unit 52 of the console 50, but this is not limiting. The image processing program 52A 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. The image processing program 52A may also be downloaded from an external device via a network.

[0122] The present disclosure can also be applied to programs and program products. Specifically, the image processing program 52A in each of the above embodiments may be provided as a program product. The program product includes any type of product for providing a program. For example, the program product includes a program provided via a network such as the Internet, and a non-transitory computer-readable recording medium such as a CD-ROM or DVD on which the program is stored.

[0123] From the above description, the invention described in the following appendix can be understood.

[0124] [Supplementary Note 1] An image processing device comprising a processor that, with the breast compressed by a compression paddle, creates a steered transmit / receive image, which is an image of the breast using ultrasound beams transmitted and received through the compression paddle by beam steering at a predetermined steering angle using an ultrasound probe, and a non-steered transmit / receive image, which is an image of the breast using ultrasound beams transmitted and received through the compression paddle by non-beam steering using the ultrasound probe, and creates a compound image using the created steered transmit / receive image and the non-steered transmit / receive image, wherein the steered transmit / receive image is an image created using frequency components that are primarily frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasound beams is half or less of the amplitude of the ultrasound beams transmitted to create the steered transmit / receive image, and the non-steered transmit / receive image is an image created using the above frequency components as primary frequency components. [Supplementary Note 2] The image processing device according to Supplementary Note 1, wherein the processor creates the compound image in a harmonic mode or a compound harmonic mode. [Supplementary Note 3] The image processing device according to Supplementary Note 2, wherein, when creating the compound image in a compound harmonic mode, the processor increases the weight of harmonic components compared to fundamental wave components for shallow areas including multiple reflections of the ultrasound beam, and increases the weight of the fundamental wave component from shallow areas to deeper areas. [Supplementary Note 4] The image processing device according to any one of Supplementary Notes 1 to 3, wherein the processor changes the setting to create the compound image when an imaging mode using the compression plate is selected. [Supplementary Note 5] The image processing device according to any one of Supplementary Notes 1 to 3, wherein the processor changes the setting to create the compound image when an image corresponding to a compression plate is recognized in at least one of the steered transmission and reception images and the non-steered transmission and reception images. [Supplementary Note 6] The image processing device according to any one of Supplementary Notes 1 to 3, wherein the processor changes the setting to create the compound image when compression by the compression plate ends.[Supplementary Note 7] The image processing device according to any one of Supplementary Notes 1 to 6, wherein the processor creates the compound image by changing a weight ratio between the steered transmitted and received image and the non-steered transmitted and received image according to the depth of multiple reflections of the ultrasonic beam. [Supplementary Note 8] The image processing device according to any one of Supplementary Notes 1 to 6, wherein the processor does not use reflected waves corresponding to between the front surface of the compression paddle, which is the surface opposite to the breast side, and the back surface, which is the surface on the breast side, and creates the compound image by making the weight of the steered transmitted and received image greater than the weight of the non-steered transmitted and received image from the back surface of the compression paddle to the depth of multiple reflections of the ultrasonic beam, and increasing the weight of the non-steered transmitted and received image as the depth becomes deeper. [Supplementary Note 9] The image processing device according to any one of Supplementary Notes 1 to 8, wherein the sound speed of the ultrasonic beam is set to a sound speed between the sound speed of the breast and the sound speed of the compression paddle. [Supplementary Note 10] The image processing device according to any one of Supplementary Notes 1 to 9, wherein the main frequency component is a frequency component of 8 MHz or less, and the steering angle is an angle of 20 degrees or less. [Supplementary Note 11] The image processing device according to any one of Supplementary Notes 1 to 9, wherein the main frequency component is a frequency component of 9 MHz or less, and the steering angle is an angle of 15 degrees or less. [Supplementary Note 12] The image processing device according to any one of Supplementary Notes 1 to 9, wherein the main frequency component is a frequency component of 11 MHz or less, and the steering angle is an angle of 10 degrees or less. [Supplementary Note 13] A medical image acquisition device comprising: the image processing device according to any one of Supplementary Notes 1 to 12; and a display unit that displays a compound image created by the image processing device.[Supplementary Note 14] A program that causes a computer to execute the following processes: while the breast is compressed by a compression plate, create a steered transmission / reception image, which is an image of the breast using an ultrasonic beam transmitted and received through the compression plate by beam steering at a predetermined steering angle using an ultrasonic probe, and a non-steered transmission / reception image, which is an image of the breast using an ultrasonic beam transmitted and received through the compression plate by non-beam steering using the ultrasonic probe; and create a compound image using the created steered transmission / reception image and non-steered transmission / reception image, wherein the steered transmission / reception image is an image created using frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasonic beam is half or less of the amplitude of the ultrasonic beam transmitted to create the steered transmission / reception image, and the non-steered transmission / reception image is an image created using the frequency components as the main frequency components.

[0125] The disclosure of Japanese Patent Application No. 2023-168674, filed on September 28, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. An image processing device comprising a processor which, while the breast is compressed by a compression plate, creates a steered transmission / reception image which is an image of the breast generated by an ultrasonic beam transmitted and received through the compression plate by beam steering at a predetermined steering angle by an ultrasonic probe, and a non-steered transmission / reception image which is an image of the breast generated by an ultrasonic beam transmitted and received through the compression plate by non-beam steering by the ultrasonic probe, and creates a compound image using the created steered transmission / reception image and non-steered transmission / reception image, wherein the steered transmission / reception image is an image created with frequency components in a range in which the amplitude of artifacts due to side lobes of the ultrasonic beam is less than half the amplitude of the ultrasonic beam transmitted to create the steered transmission / reception image, and the non-steered transmission / reception image is an image created with the above frequency components as the main frequency components.

2. The image processing device according to claim 1, wherein the processor creates the compound image in a harmonic mode or a compound harmonic mode.

3. The image processing device according to claim 2, wherein, when creating the compound image in a compound harmonic mode, the processor increases the weighting of harmonic components compared to the fundamental wave component for shallow areas including multiple reflections of the ultrasonic beam, and increases the weighting of the fundamental wave component from the shallow areas to deeper areas.

4. The image processing device according to claim 1, wherein the processor changes the settings to create the compound image when an imaging mode using the compression plate is selected.

5. The image processing device according to claim 1, wherein the processor changes the settings to create the compound image when an image corresponding to a compression plate is recognized in at least one of the steered transmitted / received image and the non-steered transmitted / received image.

6. The image processing device according to claim 1, wherein the processor changes the setting to create the compound image when compression by the compression plate is terminated.

7. The image processing device according to claim 1, wherein the processor creates the compound image by changing a weighting ratio between the steered transmitted / received image and the non-steered transmitted / received image according to the depth of multiple reflections of the ultrasonic beam.

8. The image processing device described in claim 1, wherein the processor does not use reflected waves corresponding to between the front surface of the compression plate opposite the breast side and the back surface of the compression plate on the breast side, and creates the compound image by making the weight of the steered transmitted / received image greater than the weight of the non-steered transmitted / received image from the back surface of the compression plate to the depth of multiple reflections of the ultrasonic beam, and by increasing the weight of the non-steered transmitted / received image as the depth increases.

9. The image processing device according to claim 1, wherein the sound velocity of the ultrasonic beam is between the sound velocity of the breast and the sound velocity of the compression paddle.

10. The image processing device according to claim 1, wherein the main frequency components are frequency components of 8 MHz or less, and the steering angle is an angle of 20 degrees or less.

11. The image processing device according to claim 1, wherein the main frequency components are frequency components of 9 MHz or less, and the steering angle is an angle of 15 degrees or less.

12. The image processing device according to claim 1, wherein the main frequency components are frequency components below 11 MHz, and the steering angle is an angle of 10 degrees or less.

13. A medical image acquisition device comprising: an image processing device according to claim 1; and a display unit for displaying a compound image created by said image processing device.

14. A program that causes a computer to execute a process of creating a steered transmission / reception image, which is an image of the breast compressed by a compression plate using ultrasonic beams transmitted and received through the compression plate by beam steering at a predetermined steering angle using an ultrasonic probe, and a non-steered transmission / reception image, which is an image of the breast using ultrasonic beams transmitted and received through the compression plate by non-beam steering using the ultrasonic probe, while the breast is compressed by the compression plate, and creating a compound image using the created steered transmission / reception image and non-steered transmission / reception image, wherein the steered transmission / reception image is an image created with frequency components in a range in which the amplitude of artifacts due to the side lobes of the ultrasonic beam is less than half the amplitude of the ultrasonic beam transmitted to create the steered transmission / reception image, and the non-steered transmission / reception image is an image created with the above frequency components as the main frequency components.

Images