JP2007216003A - Ultrasonographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonographic apparatus for a breast capable of excellently diagnosing the lesion of the breast without forcing burdens on a subject or an examination engineer. <P>SOLUTION: A mechanical structure is simplified by fixing an ultrasonic array probe to a rotary shaft at a prescribed angle; an ultrasonic beam is electronically controlled so that an ultrasonic wave transmission/reception direction is roughly vertical to the surface of the breast, and the data of the entire breast area including a C' part are gathered just by the rotation of the probe. Also, a membrane interposed between the probe and the breast is formed in a mesh-like structure so as to reduce multiple reflections. Further, by simultaneously displaying a B mode image and a C mode image, an accurate diagnosis is made in a short time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic inspection apparatus for diagnosing breast diseases, and more particularly to an ultrasonic breast inspection apparatus that can be used for breast cancer screening.

  Breast cancer prevalence in Japan is highest in the late 40s, and breast cancer screening by visual inspection alone was abolished in 2004, and breast cancer screening by X-ray mammography from the 40s began (for example, non Patent Document 1). However, it has been pointed out that, except for the detection of microcalcifications with a large attenuation of X-rays, the contrast of X-ray images of soft tissues in a living body that does not use a contrast agent is extremely weak, so there is a possibility that it may be missed. Also, mammography is a painful examination for the subject because the breast is sandwiched between the compression plates and is not necessarily appropriate as a screening apparatus.

  On the other hand, examinations using ultrasonic waves that are excellent in depiction of living soft tissues have been carried out, and their effectiveness has been reported. However, it has not spread widely. The first reason is that the inspection depends largely on the skill and experience of the engineer. In the current ultrasound examination, an engineer usually operates with an ultrasound probe in his hand and moves the probe against the breast to look for a section that seems to be abnormal. (This is called a tomogram) is recorded, and a doctor sees and diagnoses the recorded tomogram later. Since the probe operation is performed manually, the position of the cross-section becomes different each time, and it is difficult to obtain reproducible data, and the probability of overlooking the abnormal part depends on the skill of the engineer. In addition, it takes a long time for one person to test, and it is difficult to inspect a large number of subjects in a short time.

  On the other hand, various ultrasonic inspection apparatuses that can be used for examinations as much as possible regardless of the skill of the engineer have been tried. That is, it is a method in which the engineer moves the probe mechanically along a predetermined trajectory, collects ultrasonic data of the entire target region, and displays it as a tomographic image, instead of operating the probe by hand.

  These methods are roughly classified into a direct contact method and a water immersion method. The direct contact method is a method of displaying a cross section of the body by contacting the ultrasonic wave transmitting / receiving surface of an ultrasonic probe with the body surface (see, for example, Patent Document 1). The water immersion method is a method of transmitting and receiving ultrasonic waves by interposing a liquid such as water between the body surface and the transmission / reception surface of the ultrasonic probe. The direct contact method does not have to consider the effects of multiple reflections, but since the breast is soft tissue, the image that can be deformed when the probe moves in contact with the breast is a deformed image that is different from the stationary position. It is a drawback. In the water immersion method, since the probe does not contact the breast directly, there is almost no deformation of the breast due to the movement of the probe, but multiple reflection occurs between the probe transmission / reception surface and the film or breast surface in contact with the breast, and the image is the breast. It is a disadvantage that it is mixed in tomographic images of tissues.

  The water immersion method is further divided into a supine position (a supine position) type and a prone position (a prone position) type. In the supine position type, a water bag is applied to the breast from above while the subject is lying on the bed, and the underwater probe is mechanically moved (see, for example, Non-Patent Document 2). In the supine position, it is most natural for the subject to sleep on his / her back, but the probe in the water bag and the probe moving mechanism must be positioned above the subject and moved as a whole. Therefore, the structure is complicated, and there is no conventional example using an array probe, and only a method of mechanically reciprocating a single transducer is known.

  On the other hand, in the prone position type, there are a water tank and an ultrasonic probe in the hole of the bed with a hole, and the breast is placed in the hole and the probe is moved or rotated to collect data (for example, Patent Documents 2 and 3). In this case, a complicated structure is required to change the angle of the probe so that the ultrasonic beam is incident on the body surface at a right angle. Even with such a complicated structure, multiple reflections occur when the ultrasonic beam is incident on the body surface at a right angle. There is a drawback that good quality images cannot be obtained. In addition, there is a drawback that it is impossible to depict a flat portion near the shoulder and armpit, called C ', which has the highest incidence of breast cancer. Furthermore, in the conventional example, since the breast is directly immersed in water, the water is dirty and is not suitable for examination of a large number of subjects.

Another major problem with the ultrasound screening system is that not only the lesion site but also the whole breast including the normal site is displayed as a tomogram, so a very large number of tomograms of several hundred images must be displayed. In other words, the burden on the doctor who diagnoses by looking at a large number of tomographic images is large. This is a big difference from the X-ray mammography that can be diagnosed with a total of four images for both breasts, and this is a major problem when a tomographic image is used for examination purposes.
JP 2003-310614 A Japanese Examined Patent Publication No. 62-4989 Japanese Examined Patent Publication No. 4-14015 No. 0427001, Director of Geriatric Health Department, Ministry of Health, Labor and Welfare 2004 Ultrasound diagnosis 2nd edition, Japan Society of Ultrasound Medicine, 1994, p. 106

  As described above, various proposals have been made as an ultrasonic examination apparatus that can be used for breast cancer screening. However, examination time, breast deformation, image quality deterioration due to multiple reflections, complicated drive mechanism, water stains, many There are many problems such as a tomographic image display method, and none of the proposals has been widely used as a practical device in the conventional example.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic breast examination apparatus that can satisfactorily diagnose a breast lesion without imposing a burden on a subject or an examination engineer.

  In order to achieve the above object, the present invention takes the following measures.

  According to a first aspect of the present invention, an ultrasonic wave is transmitted to a subject based on a supplied drive signal, an echo signal is generated based on a reflected wave from the subject, and the ultrasonic wave is disposed in a liquid. An ultrasonic probe, an ultrasonic transmission / reception surface of the ultrasonic probe, and an ultrasonically permeable membrane unit that is disposed between the subject and the subject to prevent contact between the liquid and the subject; A rotation mechanism that rotates the ultrasonic probe while facing the ultrasonic transmission / reception surface of the ultrasonic probe, a drive signal generation unit that generates the drive signal and supplies the drive signal to the ultrasonic probe, and the ultrasonic probe rotates An ultrasonic inspection apparatus comprising: a control unit that controls the rotation mechanism and the drive signal generation unit so as to perform ultrasonic transmission / reception.

  According to a second aspect of the present invention, an ultrasonic probe that transmits an ultrasonic wave to a subject and generates an echo signal based on a reflected wave from the subject and is disposed in a liquid, and the ultrasonic probe An ultrasonic wave transmitting first film disposed between the ultrasonic wave transmitting / receiving surface and the subject and preventing contact between the liquid and the subject, and the first film integrated with the ultrasonic wave. An ultrasonic inspection apparatus comprising: a second film having a network structure that scatters ultrasonic waves to prevent multiple reflections.

  According to a third aspect of the present invention, an ultrasonic beam is transmitted to a subject by a plurality of ultrasonic transducers, an echo signal is generated based on a reflected wave from the subject, and a predetermined distance from the subject is set. An ultrasonic probe disposed via the ultrasonic probe, and driving the ultrasonic transducers according to the shape of the subject so that the ultrasonic beam is transmitted substantially perpendicular to the subject surface. An ultrasonic inspection apparatus comprising: a control unit that controls a signal supply timing.

  A fourth aspect of the present invention is an ultrasonic probe that transmits an ultrasonic wave to a subject and generates an echo signal based on a reflected wave from the subject and is disposed at a predetermined distance from the subject. A rotating mechanism for rotating the ultrasonic probe while the ultrasonic transmitting / receiving surface of the ultrasonic probe faces the subject, and performing ultrasonic transmission / reception while rotating the ultrasonic probe by the rotating mechanism. The control unit for acquiring ultrasonic data for at least 360 degrees regarding the subject, the data generation unit for generating voxel data in an orthogonal coordinate system using the ultrasonic data for at least 360 degrees, and the voxel An ultrasonic inspection apparatus comprising: an image generation unit that generates an ultrasonic image using data.

  As described above, according to the present invention, it is possible to realize an ultrasonic breast examination apparatus that can satisfactorily diagnose a breast lesion without imposing a burden on a subject or an examination engineer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

(First embodiment)
FIG. 1 is a block diagram of an ultrasonic inspection apparatus according to an embodiment of the present invention. As shown in the figure, the ultrasonic inspection apparatus includes an ultrasonic scanning unit A, an apparatus main body B, and a console C. The apparatus main body B includes an ultrasonic transmission unit 121, an ultrasonic reception unit 122, a B-mode processing unit 123, an image generation unit 124, a first image memory 125, a second image memory 126, an image composition unit 127, a control processor ( CPU) 128, voxel conversion unit 129, and interface unit 130. The console C includes an input device 113 and a monitor 114. Below, the function of each component will be described.

  The ultrasonic scanning unit A includes an ultrasonic array probe, a rotation mechanism that rotates the ultrasonic array probe while the ultrasonic transmission / reception surface faces the subject, a liquid container, and the like. This specific configuration will be described in detail later.

  The input device 113 is connected to the apparatus main body B, and incorporates information for instructing imaging conditions, scanning conditions, display methods, region of interest (ROI) settings, various image quality condition settings, and the like from the operator. Various switches, buttons, a trackball, a mouse, a keyboard, a lever for instructing display of a B-mode image or a C-mode image. Information input from the input device 113 is transferred to the control processor 128 via the interface unit 130.

  Based on the video signal from the image synthesis unit 127, the monitor 114 displays in-vivo morphological information (B mode image, C mode image, etc.), position information, and combination of subject information as images.

  The ultrasonic transmission unit 121 includes a trigger generation circuit, a delay circuit, a pulsar circuit, and the like (not shown). In the pulsar circuit, a rate pulse for forming a transmission ultrasonic wave is repeatedly generated at a predetermined rate frequency fr Hz (period: 1 / fr second). Further, in the delay circuit, a delay time necessary for focusing the ultrasonic wave into a beam shape for each channel and determining the transmission directivity is given to each rate pulse. The trigger generation circuit applies a drive signal to each ultrasonic transducer of the probe 12 at a timing based on this rate pulse. In addition, the ultrasonic transmission unit 121 determines the supply timing of the drive signal for each ultrasonic transducer based on the result of calculation (described later) executed to make the ultrasonic beam enter the breast surface substantially perpendicularly. Control.

  The ultrasonic receiving unit 122 includes an amplifier circuit, an A / D converter, an adder and the like not shown. The amplifier circuit amplifies the echo signal captured via the probe 12 for each channel. In the A / D converter, a delay time necessary for determining the reception directivity is given to the amplified echo signal, and thereafter, an addition process is performed in the adder. By this addition, the reflection component from the direction corresponding to the reception directivity of the echo signal is emphasized, and a comprehensive beam for ultrasonic transmission / reception is formed by the reception directivity and the transmission directivity.

  The B-mode processing unit 123 receives the echo signal from the ultrasound receiving unit 122, performs logarithmic amplification, envelope detection processing, and the like, and generates data in which the signal intensity is expressed by brightness. This data is recorded as it is in the first image memory 125 and transmitted to the image generation unit 124 to generate a B-mode image in which the intensity of the reflected wave is expressed in luminance, and the monitor 114 passes through the image composition unit 127. Is displayed.

  In addition to generating a B-mode image, the image generation unit 124 uses the voxel data generated by the voxel conversion unit 129 with the support of the input device 113 to store a C-mode image, an arbitrary cross-sectional image, and the like. Is generated. Further, the scanning line signal sequence of the ultrasonic scan is converted (scan converted) into a scanning line signal sequence of a general video format represented by a television or the like, and an ultrasonic diagnostic image as a display image is generated.

  The voxel conversion unit 129 generates orthogonal coordinate system voxel data using ultrasonic data obtained by ultrasonically scanning the ultrasonic array probe recorded in the first memory 125 while rotating in the liquid. Record in the second memory 126. This voxel data generation method will be described in detail later.

  The image composition unit 127 synthesizes the image (which may be a plurality of images) received from the image generation unit 124 together with character information, scales, and the like of various parameters, and outputs them as a video signal to the monitor 114.

  The control processor 128 has a function as an information processing device (computer), and controls all the operations of the ultrasonic scanning unit A, the ultrasonic inspection apparatus main body B, and the console C. In addition, the control processor 128 also obtains orthogonal coordinate system voxel data from various dedicated programs (for example, a phase calculation program for causing the ultrasound beam to enter the breast surface substantially perpendicularly, ultrasound data obtained in the polar coordinate system). And a control program for executing predetermined image generation / display and the like, and executes calculation / control related to various processes.

  The interface unit 130 is a device for sending information input from the input device 113 to the control processor 128.

[Ultrasonic scanning unit]
Hereinafter, the configuration of the ultrasonic scanning unit will be described in detail according to each embodiment.

Example 1
FIG. 2 is a diagram illustrating the ultrasonic scanning unit A according to the first embodiment. The liquid enclosure for storing the hot water 6 is composed of the support lid 1, the ultrasonic transmission membrane 4 and the membrane fixing part 5, and the ultrasonic array probe 2 is disposed in the hot water 6. The liquid enclosure may or may not be sealed. The ultrasonic array probe 2 is fixed to the rotating shaft 7 at a predetermined angle. The rotating shaft 7 is supported by bearings 8a and 8b, and the rotating shaft 7 is rotated by the motor 10 so that the ultrasonic array probe rotates in the liquid. . The bearings 8a and 8b are fixed to the outer cylinder 9, and the outer cylinder 9 is fixed to the tip of a support arm 13 that can be expanded and contracted. The other end of the support arm 13 is coupled to the column 19 by a coupling portion 18. The support column 19 is fixed to the support column 22. Normally, hot water is used as the liquid, and hot water is circulated by a water supply / drainage device not shown in the figure so that the water temperature is constant at about 37 degrees, and the temperature of the hot water in the container is also measured by a thermocouple so that it is always displayed. It has become.

  The subject lies on his back on the bed 17 and the examiner has handles 14a and 14b fixed to the support lid 1 of the container. The switches 15a and 15b and the handles 14b above the handles 14a and 14b are provided. Using the push-pull operation, the ultrasonically permeable membrane 4 of the liquid enclosure is placed at an appropriate position on one breast 16. The two handles 14a and 14b are positioned substantially parallel to the body axis, but in FIG. 2 are drawn perpendicular to the body axis for the sake of explanation. When the switch 15a at the upper part of the handle 14a is pressed, the arm lock (not shown) is released and the support arm 13 can be expanded and contracted, and the joint lock (not shown) is released and the joint 18 is attached to the support column 19. Can be moved up and down and rotated. In this state, the ultrasonic permeable membrane 4 of the container is placed directly above the breast. When the handle 14b is further tilted while pressing the switch 15b, the wire 20 is drawn by the second motor 23 and the connecting portion 18 is pulled up via the pulleys 21a and 21b. When the handle 14b is tilted forward, the second motor is moved. Since the wire 20 is pulled out by reverse rotation and the connecting portion descends, the handle 14b is operated to set the height of the container to an appropriate position. When the switch 15a is released, the container is fixed at that position.

  An array transducer 3 is arranged on the body surface side of the ultrasonic array probe 2, and a thin cable is connected to each transducer, which is connected to the multi-core cable 12 at the root of the ultrasonic array probe 2, and Passing through the inside and out of the hole 11 of the rotating shaft 7, the tip passes through the arm 13 and is connected to the ultrasonic transmission unit 121 and the ultrasonic reception unit 122. The multi-core cable 12 is adapted to correspond to the rotation of the rotary shaft 7 around the axis several times. Under the control of the ultrasonic transmission unit 121 and the ultrasonic reception unit 122, the ultrasonic pulse emitted from the array transducer 3 is incident on the breast tissue through the hot water 6 and the ultrasonic transmission film 4, and is reflected in the breast tissue. The reflected pulse is received by the array transducer 3 through the ultrasonic transmission film 4 and the hot water 6. Each time ultrasonic waves are transmitted / received, the ultrasonic pulse transmission / reception direction (referred to as the ultrasonic beam direction) is moved little by little from left to right in FIG. 2 (this is referred to as scanning). The image data is collected and recorded in the first memory and displayed on the monitor 114 in real time as it is for the test. Further, the data recorded in the first memory is converted into voxel data described later by the voxel conversion unit 129. It is recorded in the second memory, and a tomographic image suitable for diagnosis is generated by the image generation unit 124 using the voxel data and displayed on the display screen monitor 114.

  In order to confirm that the liquid enclosure is set at an appropriate position on the breast, the test scanning button of the input device 113 on the console C is pressed, and the ultrasonic array probe is rotated once in about 1 second to obtain a rough image. If it is not appropriate, adjust the position again and set it to an appropriate position. Thereafter, the rotation scanning button of the input device 113 is pressed, and data of a cross section in the 360 ° direction is collected, recorded and displayed. Thus, three-dimensional data is collected.

  When the data collection of one breast 16 is completed, the liquid enclosure is set on the other breast by the same method and the rotational scanning is performed in the same manner, and the data is collected, recorded and displayed. For both breasts, the time required for container setting is approximately 2 to 4 minutes, and the time required for rotational scanning is approximately 20 seconds, and the inspection is completed within 5 minutes. During this time, the subject only needs to lie on his / her back on the bed, and there is no pain.

(Example 2)
FIG. 3A is a diagram illustrating the ultrasonic scanning unit A according to the second embodiment. 2 is almost upside down, and the side surface of the support lid 1 is fixed to the outer frame 28 via the water supply / drain groove 26. In this figure, pipes 25a and 25b for circulating hot water of a constant temperature of about 37 degrees in the liquid enclosure not shown in FIG. 2 are shown. Hot water having a constant temperature flows in from the inflow pipe 25a, passes through the inside of the container, flows out from the flow outlet 24 through the outflow pipe 25b, and circulates. The flowing water port 24 is located in the upper part of the liquid enclosure, and even if bubbles are mixed in the liquid enclosure, the hot water is discharged from the flowing water port 24.

  Another difference of the system according to the second embodiment from the system according to the first embodiment is that the water supply / drainage groove 26 exists on the outer periphery of the support lid 1 of the liquid enclosure. The water supply / drainage groove 26 is supplied with hot water of about 37 degrees from the water supply pipe 27a before the subject is inspected, and the water supply / drainage groove 26 is filled and further flows onto the ultrasonic transmission film 4 to enter the ultrasonic transmission film 4. Fill the top of with warm water. At this time, the drain pipe 27b is closed. In this state, when the subject presses the breast onto the ultrasonic transmission film 4, the warm water filled on the ultrasonic transmission film 4 causes a slight gap between the ultrasonic transmission film 4 and the breast surface. After filling, the remainder overflows and passes through the water supply / drainage groove and is discharged outside through the drainage pipe 27b. At this time, the drain pipe 27b is open. The hot water discharged through the water supply / drainage groove 26 is isolated from the hot water 6 in the liquid enclosure. In this way, by supplying and draining the upper part of the ultrasonically permeable membrane 4, air bubbles are prevented from entering between the ultrasonically permeable membrane 4 and the breast surface, and the hot water that contacts the breast is replaced for each subject. It is kept clean without getting dirty. Further, in the second embodiment, the subject is bent while standing and presses the breast against the ultrasonically permeable membrane 4 of the liquid enclosure, and a handle 29a fixed to the outer frame 28 to stably support the body position. 29b, and the step platform 30 can be moved up and down according to the height.

(Example 3)
FIG. 3B is a diagram illustrating the ultrasonic scanning unit A according to the third embodiment. In this ultrasonic scanning unit, a bed is used instead of the outer frame 28 in FIG. 3A. The bed has a hole near the chest and the subject is prone on the bed so that both breasts enter the hole. FIG. 3B schematically shows a cross section 32 of a bed portion with a hole and a leg 33 that supports the cross section, the same liquid enclosure as in FIG. 3A2, a support frame 31 that supports the container, and a table 34 on which the support frame moves. Is shown in The support frame 31 is movable in the horizontal direction and has a structure in which the height can be changed up and down. The liquid enclosure moves under one of the breasts by the movement of the support frame 31, and then rises vertically to squeeze the breast and stop. Here, the ultrasonic array probe rotates to collect image data, and then the liquid enclosure drops down, moves directly under the other breast, rises again, and pushes the breast from below to collect the image data. End inspection.

[Ultrasonic transmission membrane]
Hereinafter, each component shown in each embodiment will be described in detail. 4, 5, and 6 are views showing the structure of the ultrasonic transmission film 4 of the container of FIG. 2, and the upper part represents the membrane surface and the lower part represents the cross section thereof. FIG. 4 shows a conventional ultrasonic transmission film 41 using a transparent vinyl sheet having a thickness of about 0.5 mm. This film needs to be strong enough to transmit ultrasonic waves and support the weight of the liquid in the container, and therefore cannot be made very thin. Therefore, reflection and attenuation of ultrasonic waves by the film are large.

  FIG. 5 is an explanatory diagram of a mesh film structure according to this embodiment. As shown in the lower cross-sectional view, the ultrasonically permeable membrane 42a having a reticular structure is composed of a waterproof and ultrasonically permeable thin sheet 43a and reticular fibers 44a. Since the sheet 43a does not need to support the weight of the liquid in the container, it is a soft film having elasticity such as very thin vinyl or rubber having a thickness of about 0.01 to 0.1 mm. Under the sheet 43a, there is a net made of thin fibers of about 0.5 mm with high tensile strength and flexibility, which supports the weight of the liquid. FIG. 7 shows an enlarged example of the network structure. The fibers forming the network structure 44 have a structure in which when the ultrasonic transmission film is placed on the breast, not the length of the fibers but the angle is deformed so that the fibers are easily expanded and contracted vertically and horizontally and are easily adhered to the breast surface. As shown in FIG. 1 or FIG. 2, the shape of the ultrasonic transmission film 4 is made in accordance with the average breast shape. However, when the liquid is placed on the breast, the ultrasonic transmission film 4 expands and contracts. It can also be in close contact with breasts with differences.

  FIG. 6 shows another embodiment of the ultrasonically permeable membrane. The ultrasonically permeable membrane 42b having a reticular membrane structure has a sheet 43b under the reticular fiber 44b, as shown in the lower section, and the reticular fiber 44b and the sheet. 43b is fixed and integrated. Further, a structure in which another thin sheet is placed on the mesh fiber 44b and the sheets are bonded or vacuum-bonded may be used.

  FIG. 8 and FIG. 9 are diagrams for explaining that the multiple reflection, which is the most problematic in the water immersion method, is reduced by the network film structure. For ease of explanation, the shape is slightly different from that in FIG. Multiple reflections that adversely affect the image are caused by repeated reflections between the transmission / reception surface 45 of the ultrasonic array probe and the ultrasonic transmission film 4 of the container containing the liquid or the surface 46 of the breast 16. In general, it is preferred that the ultrasound beam be emitted perpendicular to the probe's transducer surface 45 and incident perpendicularly to the breast surface 46 to avoid refraction. FIG. 8 shows a conventional example. An ultrasonic beam written by an arrow is substantially perpendicular to the transmission / reception surface 45 and the ultrasonic transmission film 41 or the breast surface 46. Since the ultrasonic transmission film 41 is also thick, repeated reflection is remarkable. It is.

  FIG. 9 shows the case of the ultrasonic transmission film 42b having the network structure shown in FIG. 6, and the ultrasonic beam is scattered in various directions by the network structure 44b on the surface of the ultrasonic transmission film 42b. Since there is little vertical reflection, multiple reflection is greatly reduced.

  Note that the ultrasonic transmission film having the network structure is not limited by the type of imaging target or the type of ultrasonic probe used for imaging, and the above-described effects can be realized by imaging using a water immersion method.

[Scanning direction of ultrasonic beam]
FIG. 10 is a diagram showing the scanning direction of the ultrasonic beam by the ultrasonic array probe 2. The array transducers 3 of the ultrasonic array probe 2 are normally arranged in a straight line, and the cross section of the wave transmitting / receiving surface 45 is a straight line. However, the breast surface is a curved surface, and its cross section is a curve. The shape of the curve is not necessarily a circular arc, and a region 48 called C ′ near the lower part of the heel, where the incidence of breast cancer is particularly high, is almost flat, and it is important to scan this part. Therefore, if the directions of the ultrasonic beams are all perpendicular to the transmitting / receiving surface and parallel to each other, it is difficult to make all incident angles on the breast surface 46 including the C ′ region 48 close to right angles. In the present embodiment, the beam direction is controlled by giving a phase difference to each vibration element of the ultrasonic array probe so that the scanning lines 47 are not necessarily parallel to each other but are as perpendicular as possible to the breast surface. . Although the scanning line 47 in the figure is shown roughly for the sake of explanation, there are actually about 200 scanning lines for 10 cm, for example.

  In addition, the phase difference given for every vibration element can be calculated as follows, for example. That is, when the breast is ultrasonically scanned while the ultrasonic array probe 2 is rotated, a reflected wave having a predetermined intensity or more is initially generated from the transmission of the ultrasonic beam on each scanning line from the first one image at the start. The shape of the breast is acquired based on the time until sound is obtained and the sound speed. Based on the resulting breast shape, the control processor 128 determines that the ultrasound beam used for ultrasound scanning of the next second image is transmitted substantially perpendicular to the breast surface. The phase difference to be given to the ultrasonic pulse from the ultrasonic transducer (that is, the delay time to be given to the drive signal of each ultrasonic transducer) is calculated. In the second and subsequent ultrasonic scans, the ultrasonic transmission unit 121 supplies a drive signal given a delay time obtained by calculation to each ultrasonic transducer. Similarly, when obtaining the third image, the delay time is calculated based on the second image. Since the rotation speed of the probe is slow, an image is taken approximately every 1 degree, and there is not much difference between adjacent images such as the first, second, second, and third images, which is sufficient. Thereby, in the ultrasonic scanning at each rotation angle, the ultrasonic beam is transmitted substantially perpendicular to the breast surface.

  When the ultrasonic beam direction is controlled so that the beam is incident on the breast surface 46 substantially perpendicularly, there is a multiple reflection reduction effect different from that of the network structure film. FIG. 11 is a diagram for explaining the effect of reducing multiple reflections. For the sake of clarity, the probe 45 is written horizontally. When an ultrasonic beam is perpendicularly incident on an oblique portion of the breast surface 46 with respect to this surface, the ultrasonic beam perpendicularly incident on the breast surface 46 is reflected in the vertical direction, and the ultrasonic wave on the transmitting / receiving surface 45 of the probe is reflected. Reach the fired part. The reached ultrasonic wave is reflected by the wave transmitting / receiving surface 45, but the direction thereof is not perpendicular to the wave transmitting / receiving surface 45 but the direction of the reflection angle. The portion where this ultrasonic wave is reflected again by the breast surface 46 and reaches the wave transmitting / receiving surface 45 is a portion away from the ultrasonic wave emitting portion, and there is almost no detection sensitivity, so that multiple reflection is greatly reduced.

  An ultrasonic beam is transmitted and received in one direction to obtain one scanning line, and the scanning line is moved little by little within the cross section to form one (one frame) image by the plurality of scanning lines. The time required for one scan line is approximately equal to the time for the ultrasonic pulse to reciprocate through the depth of the field of view of the body cross section. For example, assuming that the depth of field of view is 10 cm (reciprocation distance is 20 cm), the scanning line interval is 1 mm, and one image is generated with 100 scanning lines, the ultrasonic sound velocity (propagation speed) is about 1500 m / s. Therefore, the time required to generate one image is 100 × (2 × 0.1 m) / (1500 m / s) ≈0.013 s. If the ultrasonic array probe is rotated and one image is obtained every one degree, the time required for one rotation (360 degrees) is 0.013 s × 360 = 4.8 s, and one breast is obtained in 4.8 seconds. Scanning is completed. That is, data of all three-dimensional information of one breast can be obtained in about 5 seconds. If a two-way simultaneous reception method that generates two scanning lines by processing received signals for transmission and reception in one direction is used, one scanning line with 200 scanning lines whose scanning line density is doubled in the same time. An image can be generated.

  FIG. 12 shows a method for collecting more information. Instead of performing transmission / reception of an ultrasonic beam in one direction, for example, it is performed in 5 directions having different angles and then moved by 1 mm, and transmitted / received in 5 directions and repeated for 1 mm. The scanning time is 5 times, and in the above example, 4.8 × 5 = 24 s, that is, 24 seconds is required for scanning the entire breast, but information on reflected waves that are different in the transmission and reception directions can be obtained. .

[Image data collection, image generation and display]
Next, a method for collecting image data, generating an image, and displaying the image data will be described in detail.

  The first method is the simplest method, which records the reflected signal intensity of the received ultrasonic wave in the first memory 125 and displays the tomographic image on the monitor 114 as it is in real time. As the probe rotates, the tomographic image also changes. If it rotates 360 degrees, all cross-section data can be collected and displayed. This method is excellent in terms of simplicity, and is particularly used to check whether data collection is performed appropriately.

The second method is a display method used by a doctor for diagnosis. The data of one whole breast obtained by rotating the probe once is recorded in the first memory 125, and the data is based on the data. The voxel conversion unit 129 converts the data into voxel data of three-dimensional (hereinafter referred to as 3D) orthogonal coordinates and records it. FIG. 13 is a diagram showing the ultrasonic array probe of FIG. 2, FIG. 3A or FIG. 3B and its rotation axis. The rotation axis is the z-axis, the point where the probe transmission / reception surface intersects the z-axis is the origin, and the direction passing through the origin and perpendicular to the z-axis is the x-axis. FIG. 13 shows the case where the probe is in the direction of the rotation start position, that is, the direction perpendicular to the body axis. Ultrasound is transmitted and received in the direction of α degrees from the direction perpendicular to the transmission / reception surface at a point of distance R along the transmission / reception surface of the probe from the origin, and the reflected signal from the point (x, z) at a distance of depth r. Consider the case of receiving. When the coordinates (x, z) of this point are obtained,
(Formula 1) x = (R + r sinα) cosθ-r cosα sinθ
(Formula 2) z = (R + r sinα) sinθ + r cosα cosθ
It becomes. θ is a value determined by the apparatus, the values of R and α are known from transmission / reception control signals, and r is obtained from the propagation time of the ultrasonic wave reciprocating at a distance of depth r. FIG. 14 is a top view of FIG. 13 and shows how the probe rotates about the z axis. If the axis passing through the origin and orthogonal to the x axis is the y axis, the position coordinate (x, y, z) of the reflected wave from the distance R and the depth r in the angle α direction when rotated by φ degrees from the start position is It is expressed by the following formula.

(Formula 3) x = [(R + r sinα) cosθ-r cosα sinθ] cosφ
(Formula 4) y = [(R + r sinα) cosθ-r cosα sinθ] sinφ
(Formula 5) z = (R + r sinα) sinθ + r cosα cosθ
The reflected signal intensity of the ultrasonic wave reflected from the point of coordinates (x, y, z) is first recorded in the first memory 125 together with the values of (R, r, α, φ). Next, the reflected signal recorded in the first memory 125 is subjected to coordinate transformation equations (Equation 3) (Equation 4) (Equation 5) by using the values of (R, r, α, φ) by the voxel transformation unit 129. Is converted into the orthogonal coordinates of (x, y, z) and recorded in the second memory 126. This is the voxel data shown in FIG. As shown in FIG. 15, the number of voxels is N1, N2, and N3 finite values in the x, y, and z directions, respectively, and is not a continuous value. Therefore, one voxel has two or more data. In this case, the average value is used, and the average value of the data of the surrounding voxels is entered in the voxel for which no data exists. In this way, by converting all 3D data into rectangular coordinates and recording them in the memory, 3D voxel data is obtained as shown in FIG. Using the voxel data obtained in this way, any display method such as B mode, C mode, composite image, and stereoscopic view is possible. In the above example, when the scanning direction at one point is performed for five directions, five sets of voxel data are collected.

  As a specific display method, first, a vertical cross section display generally called B mode, that is, a cross section display parallel to the z axis, while moving a large number of cross sections constituting the entire breast in parallel to the body axis direction or There is a method of sequentially displaying while rotating about the z axis. The input device 113 of the console C has a display mode selection button. A display method is selected by the selection button, and tomographic images are sequentially displayed by a lever of the input device 113. When the lever is tilted away from the center position, a plurality of cross-sections are displayed one after another, and when the lever is tilted forward from the center position, it can be returned in the reverse direction. The display speed can be changed stepwise or continuously depending on the angle of the lever. In each tomographic image, ID information capable of specifying the position of the cross section is recorded, and the position of the tomographic image automatically obtained from the ID information and the ID information is displayed on the same screen by a marker on the same screen. For example, when the position of the tomographic image to be displayed is moved in the body axis direction, the left or right of the breast is represented by L and R, the z-axis coordinate is represented by a numerical value, and the cross section is moved and displayed in the rotation direction The rotation angle φ is recorded and displayed, and the position of the cross section is displayed in a straight line on the breast pattern simulated as a circle. When an abnormal part is found, the lever is adjusted to display the optimum cross section and record as a still image. Since the ID information is also recorded in this image, the image of this part can be easily reproduced from the recorded 3D data by designating this ID in reexamination and the like.

  Another method is a method of displaying a plurality of cross sections sequentially while moving in the z direction by displaying a cross section perpendicular to the z-axis, usually called C mode. The operation method for observing the image is the same as in the B mode. In C mode, since the number of sheets is relatively small, they can be displayed side by side on a single screen or displayed on a photographic film.

  The method that seems to be most preferable is a method in which B-mode and C-mode images are displayed side by side on one screen, and one of the images is moved and its position is displayed on another image with a marker. FIG. 16 shows an example of the display. A B-mode image 52a is displayed above the monitor 114, and a C-mode image 53 is displayed below it. The C mode is a horizontal tomographic image parallel to the body axis, and the position of the displayed cross section is displayed as a horizontal line 54 in the B mode image displayed thereon. On the other hand, it can be seen that the B-mode image displayed at the top is a cross section displayed by the straight line 55a on the lower C-mode image. When the abnormal part 57 is found, the optimum cross section suitable for observation is fixedly displayed, and when the lever is operated after aligning the vertical line 56 on the B mode with the abnormal part 57, the straight line 56 is displayed as shown in FIG. The B mode image rotated and moved as the axis is sequentially displayed on the upper part of the screen, and the position of the cross section is displayed as a straight line 55b on the lower C mode image. By such a display method, a doctor can diagnose a large number of tomographic images in a short time and in detail.

  As another method, for example, the scanning direction at one point is changed to five directions, for example, as shown in FIG. 12, and five types of image data in each direction are added and displayed. In this method, images are stopped and images in a plurality of directions of the cross section are arranged and compared on the same screen. The added image reduces speckle (spotted pattern) and multiple reflection, improves the signal-to-noise ratio, and provides a smooth and easy-to-view image. In addition, images transmitted and received in different directions have slightly different information, which is useful for more accurate diagnosis.

  According to the above-described embodiment, since the ultrasonic array probe is fixed to the rotating shaft in the liquid, the structure becomes very simple, and the ultrasonic array probe is electronically controlled by controlling the transmission / reception direction of the ultrasonic beam. Can be transmitted and received in a direction as perpendicular to the breast surface as much as possible, multiple reflections can be reduced, and scanning of the C ′ portion, which is difficult to scan, can be performed, and the breast fixed in a short time. Thus, various display methods suitable for diagnosis can be made.

  Further, since the liquid enclosure is configured to move and set to an appropriate position on the breast, the subject can be examined in the most preferable posture of supine position.

  Furthermore, by supplying and draining the liquid separately from the liquid in the liquid enclosure at the top of the liquid enclosure installed at the bottom of the body surface, there are no bubbles on the breast surface and a good image is obtained. The liquid in contact with the surface is almost free from dirt and kept clean.

  Also, by transmitting and receiving an ultrasonic beam in a direction as perpendicular as possible to the breast surface by electronic control, the structure becomes simple, multiple reflections can be reduced, and the C ′ portion, which is difficult to scan, can be reduced. Scanning is also possible.

  In addition, by forming the ultrasonically permeable film of the liquid-sealed container into a reticular film structure, it is possible to reduce multiple reflection, which is the biggest problem in the water immersion method, increase the ultrasonic transmission power and ensure the strength of the container. .

  Using image data obtained by transmitting and receiving ultrasound from multiple directions, multiple reflections can be reduced, speckles can be reduced, and the signal-to-noise ratio can be improved. Information useful for diagnosis also increases, and it is possible to depict a duct directly under the nipple, which is usually difficult to see.

  By generating or synthesizing images scanned from the same cross section from different directions, images with different diagnostic information due to differences in transmission and reception directions can be displayed, confirmation and reduction of multiple reflections, speckle reduction, signal to noise ratio Improvement is possible.

  In addition, by converting image data collected over the entire area of the breast into voxel data and generating various images from the voxel data, images suitable for diagnosis can be obtained using general-purpose hardware and software for image processing. It can be easily generated and displayed.

  Furthermore, B-mode images and C-mode images are displayed at the same time and one image is sequentially switched, and each cross-sectional position is displayed, so that several hundred tomographic images can be observed in a short time and abnormal sites can be detected. Detailed inspection is possible.

  In addition, by recording cross-sectional position information on each tomographic image and automatically displaying the cross-sectional position with a marker on the screen based on the recorded information, the position of the displayed cross-section can be intuitively grasped. At the same time, it is easy to search for a section to be displayed, and a necessary image can be easily displayed on the screen.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage.

  For example, each function according to the present embodiment can also be realized by installing a program for executing the processing in a computer such as a workstation and developing these on a memory. At this time, a program capable of causing the computer to execute the technique is stored in a recording medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory. It can also be distributed.

In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  As described above, according to the present invention, it is possible to realize an ultrasonic breast examination apparatus that can satisfactorily diagnose a breast lesion without imposing a burden on a subject or an examination engineer.

FIG. 1 is a block diagram of an ultrasonic inspection apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the ultrasonic scanning unit A. FIG. 3A is a diagram illustrating the ultrasonic scanning unit A according to the second embodiment. FIG. 3B is a diagram illustrating the ultrasonic scanning unit A according to the third embodiment. FIG. 4 is a diagram showing an example of an ultrasonic transmission film of the liquid enclosure. FIG. 5 is a diagram for explaining the ultrasonically permeable membrane of the liquid enclosure. FIG. 6 is a diagram for explaining another example of the ultrasonic transmission film of the liquid enclosure. FIG. 7 shows an example of the film structure. FIG. 8 is a diagram for explaining multiple reflection. FIG. 9 is a diagram for explaining the multiple reflection mitigation. FIG. 10 is a diagram for explaining an ultrasonic beam that is not perpendicular to the transmission / reception surface. FIG. 11 is a diagram for explaining an effect of reducing multiple reflections of an ultrasonic beam emitted obliquely. FIG. 12 is a diagram for explaining a case where ultrasonic transmission / reception is performed in a plurality of directions. FIG. 13 is a diagram for obtaining an expression that expresses the position of the reflector in rectangular coordinates. FIG. 14 is a view of FIG. 13 viewed from the z-axis direction. FIG. 15 is a diagram for explaining voxel data. FIG. 16 is a diagram for explaining simultaneous display in the B mode and the C mode according to the embodiment of FIGS. 2 to 3B. FIG. 17 is a view showing an example in which the abnormal site according to the embodiment of FIGS. 2 to 3B is displayed in another cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Support lid | cover of liquid enclosure container, 2 ... Ultrasonic array probe, 4 ... Ultrasonic permeable film of liquid enclosure container, 7 ... Rotating shaft, 10 ... Motor, 24 ... Liquid enclosure container inlet, 25a ... Liquid enclosure container inflow Pipe, 25b ... Liquid-filled container outflow pipe, 26 ... Water supply / drainage groove, 27a ... Water supply pipe for water supply / drainage groove, 27b ... Water drainage pipe for water supply / drainage groove, 31 ... Support frame for moving the liquid enclosure, 42 ... Super-reticulated structure Sound transmitting film 45 ... Transmission / reception surface of ultrasonic probe, 46 ... Breast surface, 47 ... Ultrasonic transmission / reception direction (scanning line), 48 ... C dash region, 50 ... Voxel, 52a ... Rotated display about z axis B mode image, 52b ... B mode image rotated and displayed around the abnormal part, 53 ... C mode image, 54 ... Cross position of the C mode image, 55 ... Cross position of the B mode image, 56 ... Others passing through the abnormal part No B Lines for displaying an image, 57 ... abnormalities

Claims (19)

An ultrasonic probe that transmits an ultrasonic wave to a subject based on a supplied drive signal, generates an echo signal based on a reflected wave from the subject, and is disposed in a liquid;
An ultrasonically permeable membrane unit that is disposed between the ultrasonic transmission / reception surface of the ultrasonic probe and the subject, and prevents contact between the liquid and the subject;
A rotating mechanism for rotating the ultrasonic probe while facing the ultrasonic transmission / reception surface of the ultrasonic probe to the subject;
A drive signal generation unit that generates the drive signal and supplies the drive signal to the ultrasonic probe;
A control unit that controls the rotation mechanism and the drive signal generation unit so that ultrasonic transmission and reception is performed while the ultrasonic probe rotates;
An ultrasonic inspection apparatus comprising:   The ultrasonic examination apparatus according to claim 1, wherein the film unit has a shape for contacting the breast of the subject.   The ultrasonic inspection apparatus according to claim 1, wherein at least a part of the film unit has elasticity. The membrane unit is
A first membrane having ultrasonic permeability and waterproof properties;
A second film having a network structure for scattering ultrasonic waves to prevent ultrasonic multiple reflection;
The ultrasonic inspection apparatus according to claim 1, further comprising:   The ultrasonic inspection apparatus according to claim 1, further comprising a water supply / drainage unit for supplying and discharging the liquid.   6. The container according to claim 1, further comprising a container for containing the ultrasonic probe and the liquid and for placing a contact surface formed by the membrane unit on the upper side with respect to the subject. The ultrasonic inspection apparatus as described in any one of them.   7. A container for accommodating the ultrasonic probe and the liquid and for placing a contact surface formed by the membrane unit below the subject. The ultrasonic inspection apparatus as described in any one of these.   The ultrasonic inspection apparatus according to claim 1, wherein an angle formed between an ultrasonic transmission / reception surface of the ultrasonic probe and the rotation axis of rotation is not a right angle. According to the shape of the subject surface, further comprising a calculation unit for calculating a delay time of the drive signal for each ultrasonic transducer of the ultrasonic probe,
The control unit controls the drive signal generation unit so that each drive signal is supplied to each ultrasonic transducer according to the calculated delay time;
The ultrasonic inspection apparatus according to claim 1, wherein:   The calculation unit calculates a delay time of a drive signal for each ultrasonic transducer of the ultrasonic probe so that an ultrasonic wave is transmitted in a direction substantially perpendicular to the subject surface. The ultrasonic inspection apparatus according to claim 9.   The ultrasonic inspection apparatus according to claim 1, further comprising a unit that generates or synthesizes images obtained by scanning the same cross section from different directions.   The ultrasonic inspection apparatus according to claim 1, further comprising a unit that converts the collected image data into voxel data, generates various images from the voxel data, and selectively displays the images. .   2. A display unit that simultaneously displays a B-mode image and a C-mode image, sequentially switches one image to a different cross-section, and displays the cross-sectional position of the counterpart image on each image. 12. The ultrasonic inspection apparatus according to 12.   13. The ultrasonic inspection apparatus according to claim 12, further comprising a display unit that records cross-sectional position information in each of the tomographic images and automatically displays the cross-sectional position with a marker on the screen based on the recorded information.   14. The ultrasonic breast examination apparatus according to claim 13, further comprising a display control unit that controls a function of changing the speed of sequential switching to different sections stepwise or continuously, forward / reverse switching, and stillness of an image.   The ultrasonic inspection apparatus according to claim 1, further comprising a temperature display unit that displays a temperature of the liquid. An ultrasonic probe that transmits an ultrasonic wave to the subject and generates an echo signal based on a reflected wave from the subject, and is disposed in the liquid;
An ultrasonically transmissive first film disposed between an ultrasonic wave transmitting / receiving surface of the ultrasonic probe and the subject, and preventing contact between the liquid and the subject;
A second film integrated with the first film and having a network structure for scattering ultrasonic waves to prevent ultrasonic multiple reflection;
An ultrasonic inspection apparatus comprising: An ultrasonic probe that transmits an ultrasonic beam to a subject by a plurality of ultrasonic transducers, generates an echo signal based on a reflected wave from the subject, and is disposed at a predetermined distance from the subject; ,
A control unit for controlling the supply timing of the drive signal to each of the ultrasonic transducers according to the shape of the subject so that the ultrasonic beam is transmitted substantially perpendicular to the subject surface; ,
An ultrasonic inspection apparatus comprising: An ultrasonic probe that transmits an ultrasonic wave to the subject and generates an echo signal based on a reflected wave from the subject, and is disposed at a predetermined distance from the subject;
A rotating mechanism for rotating the ultrasonic probe while facing the ultrasonic transmission / reception surface of the ultrasonic probe to the subject;
A control unit that acquires ultrasonic data for at least 360 degrees with respect to the subject by performing ultrasonic transmission and reception while rotating the ultrasonic probe by the rotation mechanism;
A data generation unit for generating voxel data in an orthogonal coordinate system using the ultrasonic data for at least 360 degrees;
An image generation unit that generates an ultrasound image using the voxel data;
An ultrasonic inspection apparatus comprising:

Images