JP4787569B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus and a probe, and more particularly to a structure of a 2D array transducer and a 2D beam steering technique.

  The ultrasonic diagnostic apparatus is used for diagnosing a disease of a patient in the medical field. Specifically, the ultrasonic diagnostic apparatus transmits an ultrasonic wave to a living body, receives a reflected wave from the living body, and forms an ultrasonic image based on a reception signal obtained by the reception.

  A two-dimensional (2D) array transducer is used to two-dimensionally scan the ultrasonic beam, thereby forming a three-dimensional echo data capturing space (three-dimensional space) in the living body. A 2D array transducer is generally composed of a plurality of two-dimensionally arranged vibration elements, which are generally arranged in a planar shape.

  Patent Document 1 describes a 2D array transducer configured by arranging a plurality of vibration elements on a convex cylindrical surface. For the 2D array transducer, it is possible to apply electronic sector scanning in the direction of the central axis of the cylinder and apply electronic linear scanning in the circumferential direction (FIGS. 1 and 2). . Patent Document 2 describes a 2D array transducer configured by arranging a plurality of vibration elements in a planar shape. With respect to the 2D array transducer, it is possible to apply electronic sector scanning in the first direction and electronic linear scanning in the second direction (FIG. 2). Patent Document 3 shows a configuration in which a phasing addition unit is provided in two stages.

Patent No. 2851005 US Pat. No. 6,238,346 JP 2000-33087 A

  A 2D array transducer is generally composed of thousands (eg, 3000) of vibration elements. Therefore, when a transmitter and a receiver are individually connected to each vibration element, the electronic circuit scale increases. In addition, a large number of signal lines must be inserted into the probe cable, which increases the thickness of the probe cable and increases its weight, thereby degrading the operability of the probe. Each of the above patent documents discloses channel reduction or a related technique, but does not provide a probe or an ultrasonic diagnostic apparatus suitable for ultrasonic diagnosis of the heart or the like. For example, in the case of using the 2D array transducer shown in FIG. 1 of Patent Document 1, since the ultrasonic beam moves over a wide range from the vicinity of the probe (because the top of the three-dimensional space is large), ultrasonic diagnosis is performed through the intercostal space. It is difficult to do.

  An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of achieving channel reduction and forming a good three-dimensional transmission / reception space, and a probe used therefor.

  Another object of the present invention is to provide an ultrasonic diagnostic apparatus suitable for performing three-dimensional ultrasonic diagnosis on the heart and a probe used therefor.

  Another object of the present invention is to increase the bandwidth of the probe.

(1) An ultrasonic diagnostic apparatus according to the present invention includes an array transducer including a plurality of transducer elements arranged in a concave cylindrical surface, and transmission / reception means connected to the array transducer, The vibration element includes a plurality of vibration element arrays aligned in a cylindrical central axis direction, each vibration element array includes a plurality of vibration elements aligned in a circumferential direction, and the transmission / reception means includes the cylindrical central axis. A first electronic scan as an electronic sector scan or an electronic linear scan in the direction, and a second electronic scan as an electronic linear scan in the circumferential direction . A switching unit configured to set a concave cylindrical surface-shaped two-dimensional aperture and scan the two-dimensional aperture in the circumferential direction; a transmission unit connected to the array transducer via the switching unit; A receiving unit connected to the array transducer via the switching unit, and at each set position of the two-dimensional opening in the circumferential direction, in both the cylindrical central axis direction and the circumferential direction At the same time, the ultrasonic beam is scanned in the direction of the central axis of the cylinder while focusing the ultrasonic beam to form a scanning surface, and the scanning surface is scanned in the circumferential direction, so that a three-dimensional space having a converging portion is formed. It is formed . Preferably, means for variably setting the opening size in the circumferential direction of the two-dimensional opening is provided.

  According to the above configuration, the array transducer has a concave cylindrical surface shape, and is preferably configured by a plurality of vibration element rows arranged linearly, and each vibration element row has a plurality of vibrations arranged in an arc shape. It is composed of elements. Each vibration element is configured as a single vibration member or a combination of a plurality of vibration members, and the shape thereof is, for example, a square or a rectangle. The curvature in the circumferential (arc) direction of the array transducer is preferably constant at any position in the direction, but may continuously change in the direction.

When the first electronic scanning (electronic sector scanning or electronic linear scanning) is applied to the array transducer in the direction of the central axis of the cylinder and the second electronic scanning (electronic linear scanning) is applied to the circumferential direction, ultrasonic waves The beam is scanned two-dimensionally, thereby forming a three-dimensional space (three-dimensional echo data capturing space). In other words, the two-dimensional scanning surface formed by the first electronic scanning is swung by the second electronic scanning, thereby forming a three-dimensional space. In that case, the three-dimensional space is generally constricted in the vicinity of the central axis of the cylinder, so that ultrasonic waves can be transmitted and received satisfactorily through a gap between structures such as the ribs. In electronic linear scanning, beam deflection control may be combined and applied in all or part of the circumferential direction. In the above configuration, the first electronic scan is preferably an electronic sector scan. In this case, for example, the scanning surface formed by electronic sector scanning is electronic linearly scanned in an arc shape. Since two electronic scans are applied in two directions, that is, a two-dimensional aperture is set, the focusability of the ultrasonic beam can be further improved .

  In the second electronic scanning, the transmission / reception aperture is scanned in the circumferential direction. In this case, the transmission aperture and the reception aperture generally match, but for example, the transmission aperture may be reduced and the reception aperture may be set larger. For example, it is possible to provide a plurality of receiving openings for one transmitting opening in the direction of the central axis of the cylinder. According to this, a plurality of reception beams can be simultaneously formed (simultaneous reception). Further, a plurality of receiving beams can be simultaneously formed by connecting a plurality of phasing and adding means in parallel to a common receiving aperture. A plurality of reception beams may be simultaneously formed in the circumferential direction without being limited to the cylindrical central axis direction. Depending on the depths of the transmission focus point and the reception focus point, the opening sizes in the cylindrical central axis direction and the circumferential direction may be varied. Further, each signal may be weighted in the opening as in the conventional case. One or a plurality of reactive vibration elements may be included in the plurality of vibration elements constituting the array vibrator.

  Preferably, the ultrasonic beam is two-dimensionally scanned by executing the first electronic scan and the second electronic scan, thereby forming a three-dimensional space having a focusing portion. Preferably, the focusing portion is a portion including a cylindrical central axis. Desirably, the said converging site | part is set in the position corresponded between the ribs of a human body (living body) or its vicinity. The converging part ideally corresponds to one line (a line that coincides with the central axis of the cylinder or a parallel line), but in reality, the converging part is a part having a slight spread. From another viewpoint, the converging site is a constricted portion. Since the array transducer has the shape of a concave cylindrical surface, for example, a large three-dimensional capture space can be formed on the back side through a specific intercostal space while avoiding ribs. That is, the ultrasonic wave can sufficiently reach the rear side of the rib, and the echo from the rear side can be received with high sensitivity.

  Preferably, the transmission / reception means includes a switching unit for scanning an opening in the circumferential direction on the array transducer, a transmission unit connected to the array transducer via the switching unit, And a receiving unit connected to the array transducer via the switching unit.

  The switching section functions as an opening selection section, and a plurality of signal lines corresponding to the vibration element array are connected to one terminal row in the switching section, and a plurality of vibrations constituting the vibration element row are connected to the other terminal example. Elements are connected. Channel reduction is achieved by setting the aperture.

  Preferably, the switching unit includes a plurality of switching circuits provided corresponding to the plurality of vibration element arrays, and the reception unit includes at least one first phasing and adding circuit set and the first rectifying circuit. A second phasing addition circuit provided at least one for each phase addition circuit set, and the first phasing addition circuit set includes a plurality of vibration elements belonging to the opening for each of the vibration element rows. It comprises a plurality of first phasing and adding circuits that execute a first phasing and adding process for a plurality of received signals to be output, and the second phasing and adding circuit is a first phasing and adding circuit set corresponding thereto. A second phasing addition process is performed on the plurality of first phasing addition signals output from the.

  According to the above configuration, since at least one first phasing / adding circuit set is the preceding stage and at least one second phasing / adding circuit is provided in the subsequent stage, the sub-phasing in each vibration element array is provided in the preceding stage. The main phasing addition processing can be executed on the signal after the sub phasing addition in the subsequent stage by executing the addition processing. Each first phasing and adding circuit set includes a plurality of first phasing and adding circuits provided corresponding to the plurality of switching circuits. When a plurality of reception beams are simultaneously formed in the circumferential direction, a plurality of first phasing and adding circuit sets are arranged in parallel. At least one second phasing and adding circuit is provided for each first phasing and adding circuit set. When a plurality of reception beams are simultaneously formed in the cylindrical axis direction, a plurality of second phasing and adding circuits are arranged and arranged for one first phasing and adding circuit set.

  Preferably, the array transducer and the switching unit are provided in a probe head. Preferably, the array transducer, the switching unit, the at least one first phasing and adding circuit set, and the transmission unit are provided in a probe head. According to these configurations, channel reduction is performed in the probe head, and the number of signal lines constituting the probe cable can be reduced.

  Preferably, an additional beam deflection scan for enlarging the three-dimensional space is performed following the second electronic scan at both ends in the circumferential direction. According to this configuration, both end portions of the three-dimensional space can be enlarged. Therefore, the additional deflection scanning as described above may be performed as necessary.

  Preferably, a medium for acoustic matching is provided on the living body side of the array transducer. Preferably, in the process of performing the second electronic scan in the circumferential direction, beam deflection control is performed to correct the beam direction in response to refraction of the ultrasonic beam at the interface between the medium and the living body. Applied. Preferably, each ultrasonic beam intersects at a beam crossing site by the second electronic scanning with the beam deflection control in the circumferential direction.

  A medium is provided between the array transducer and the living body. Such a medium may also serve as a matching layer, or may be a member provided on the living body side in addition to the matching layer. When the sound speed of the medium and the sound speed of the living body are the same, the ultrasonic beam is not refracted at the boundary surface, but when they are different, the ultrasonic beam is refracted at the boundary surface, and as a result, three-dimensional There arises a problem that the space is distorted or each ultrasonic beam does not pass through the converging site. Therefore, in the process of the second electronic scanning (electronic linear scanning) in the circumferential direction, beam deflection control (fine angle deflection control) is applied to each beam address to correct the beam direction of each ultrasonic beam, It is desirable to cross at the focusing site.

(2) An ultrasonic diagnostic apparatus according to the present invention is provided with an array transducer including a plurality of transducer elements arranged in a concave cylindrical surface, and is arranged on the upper surface side of the array transducer and is aligned in the direction of the center axis of the cylinder A plurality of matching layers, and transmitting and receiving means connected to the array vibrator, wherein the plurality of vibration elements are constituted by a plurality of vibration element arrays aligned in a cylindrical central axis direction, and each vibration element array Is constituted by a plurality of vibrating elements aligned in the circumferential direction, and the transmitting / receiving means performs a first electronic scan as an electronic sector scan or an electronic linear scan in the cylindrical central axis direction, and the circumferential direction A second electronic scan as an electronic linear scan, and the transmission / reception means sets a concave cylindrical surface-shaped two-dimensional aperture on the array transducer and scans the two-dimensional aperture in the circumferential direction. Sui And a receiving unit connected to the array transducer via the switching unit and a receiving unit connected to the array transducer via the switching unit. At each set position of the two-dimensional opening in the direction, the ultrasonic beam is scanned in the cylindrical central axis direction while the ultrasonic beam is focused in both the cylindrical central axis direction and the circumferential direction. And the scanning plane is scanned in the circumferential direction to form a three-dimensional space having a converging portion, each matching layer is provided for each vibration element array, and each matching layer is arranged in the circumferential direction. It has the curved form which continues along a direction, It is characterized by the above-mentioned.

  In the 2D array vibrator, each vibration element is minutely formed. When an independent matching element (matching layer) is provided for each vibration element, the matching element is also finely formed. Then, usually, the function of acoustic matching is lowered, and it becomes difficult to secure a necessary frequency band. That is, if the matching element is miniaturized, the wavefront is less likely to propagate in a plane wave in the inside thereof, and the matching action is reduced. In particular, when an image is formed based on harmonics included in the received signal, it is required to expand the frequency band.

  According to the said structure, each matching layer is provided for every circular-arc-shaped vibration element row | line | column, and it is comprised as an integrated member continuous in circular arc shape. Therefore, it is possible to prevent a decrease in the matching effect and secure a frequency band.

  Generally, when a plurality of matching elements are connected to each other, the directivity angle in the connecting direction becomes narrow. That is, when the ultrasonic beam is largely deflected, sufficient sound pressure and sensitivity cannot be obtained. In the above configuration, electronic linear scanning is applied as the second electronic scanning in the circumferential direction, and there is no need to greatly deflect the ultrasonic beam in the circumferential direction (even if deflection scanning control is performed at the end). Therefore, even if a matching layer that is continuous in the circumferential direction is provided, no major problem occurs in terms of directivity characteristics. On the other hand, when electronic sector scanning is applied in the direction of the central axis of the cylinder, it is necessary to ensure a sufficient directivity angle characteristic for each vibration element in that direction, so that a plurality of matching layers are separated from each other in that direction. Is desirable. Note that a clogging material having an acoustic impedance that does not significantly adversely affect the vibration action and the matching action may be filled between the adjacent vibration elements and the adjacent matching layers.

  In the above-described configuration, a plurality of vibration elements arranged in the circumferential direction are held in the matching layer, which has an advantage that each vibration element is structurally strengthened and the collapse thereof can be prevented. That is, durability can be improved.

  Preferably, the plurality of matching layers are divided from each other in the direction of the central axis of the cylinder. Preferably, a plurality of cuts are formed in each matching layer in an arrangement corresponding to a plurality of inter-element grooves in each vibration element row. The incision is set at a depth that does not cut all of the matching layer in the thickness direction (cuts it halfway). By adjusting the depth (that is, adjusting the degree of connection between adjacent matching elements), the matching action (adjustment of ultrasonic band, directivity angle) can be adjusted. Each cut may be formed from the living body side or from the non-living body side. Alternatively, a cut portion may be provided from both sides so that the connection portion remains in the middle of the thickness direction between the matching elements. A plurality of matching layers stacked may be provided for each vibration element array.

(3) Preferably, in the probe for an ultrasonic diagnostic apparatus including a probe head and a probe cable , the probe head includes an array transducer including a plurality of vibration elements arranged in a concave cylindrical surface, and the array The vibrator is composed of a plurality of vibrating element arrays aligned in the direction of the central axis of the cylinder to which the second electronic scanning as the electronic sector scanning or the electronic linear scanning is applied, and each of the vibrating element arrays is a first as the electronic linear scanning. It is constituted by a plurality of vibration elements aligned in the circumferential direction to which two-electron scanning is applied . The number of vibration element arrays and the number of vibration elements constituting the vibration element array are each 2 or more, preferably each an integer of several tens or more. The array transducer has a shape such as a rectangle, a hexagon, an octagon, or a circle.

  Desirably, the beam cross site in the electronic linear scanning is positioned at a depth in or near the intercostal space in the living body with the wave transmitting / receiving surface of the probe head in contact with the surface of the living body chest.

  Desirably, the vibration element size in the circumferential direction is larger than the vibration element size in the cylindrical central axis direction. There may be a problem due to a difference in resolution between the central axis direction of the cylinder where the first electronic scanning is performed and the circumferential direction where the second electronic scanning is performed (problem due to the worse resolution in the circumferential direction). There is. In that case, it is desirable to employ the above configuration. It should be noted that the beam scan pitches are preferably aligned in both directions, but they need not necessarily coincide.

  Preferably, a switching unit for scanning the opening in the circumferential direction in the second electronic scanning is provided in the probe head. Desirably, a means for adding a plurality of received signals in the opening is provided for each of the vibrating element rows in the probe head. The addition of a plurality of received signals may be simple addition, but delay addition (phased addition) is desirable in order to further improve signal processing accuracy.

(4) Preferably, in the probe for an ultrasonic diagnostic apparatus including a probe head and a probe cable, the probe head includes an array transducer including a plurality of transducer elements arranged in a concave cylindrical surface, and the array transducer A plurality of matching layers aligned in the cylindrical central axis direction, and the array transducer is a cylindrical central axis to which first electronic scanning as electronic sector scanning or electronic linear scanning is applied A plurality of vibration element rows arranged in a direction, each vibration element row being constituted by a plurality of vibration elements arranged in a circumferential direction to which a second electronic scan as an electronic linear scan is applied, and A layer is provided for each of the vibration element rows, and each matching layer has a curved shape that continues along the circumferential direction .

  As described above, according to the present invention, channel reduction can be performed within the probe. According to the present invention, a good ultrasonic diagnosis can be performed from the gap of the structure even when the structure is present directly under the body surface. Or according to this invention, the three-dimensional diagnosis of the heart can be performed favorably. According to the present invention, a wide band can be achieved by devising the structure of the matching layer.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a transmission / reception unit in the ultrasonic diagnostic apparatus according to the present invention. The ultrasonic diagnostic apparatus includes a probe and the apparatus main body 12. The probe includes a probe head 10, a probe cable 14, and a probe connector (not shown). This ultrasonic diagnostic apparatus is a medical apparatus that transmits and receives waves to a living body and forms an ultrasonic image based on a reception signal obtained thereby. In this embodiment, as will be described later, a three-dimensional echo data capturing space (three-dimensional space) is formed, and a three-dimensional image is formed based on the volume data obtained therefrom.

  In the configuration shown in FIG. 1, a 2D array transducer 16 and a switch unit 24 are provided in a probe head 10 operated by a user. However, a first module 34 and a second module 42 which will be described later may be accommodated in the probe head 10. That is, the probe cable 14 is provided after the second module 42.

  The 2D array transducer 16 includes a plurality of vibration elements 20a. Specifically, the 2D array transducer 16 has a curved shape, and a plurality of vibration elements 20a are two-dimensionally arranged in a concave cylindrical surface. That is, when the cylindrical center axis 18 is defined as shown in the figure as the center of curvature of the concave cylindrical surface, the 2D array transducer 16 curved with a certain curvature around the cylindrical center axis 18 is configured.

  Here, the X direction is a direction parallel to the cylindrical central axis 18, and in this embodiment, the direction in which electronic sector scanning is performed. Electronic linear scanning can be applied instead of electronic sector scanning. The arc-shaped θ direction is the circumferential direction, which is the direction of electronic linear scanning according to the concave method. The 2D array transducer 16 includes m transducer element arrays 20 linearly aligned in the X direction. Each vibration element array 20 includes n vibration elements 20a aligned in the θ direction. Each vibration element 20a is configured as a single vibration body or a structure in which a plurality of vibration bodies are electrically connected. In the example illustrated in FIG. 1, the size in the θ direction is larger than the size in the X direction in each vibration element 20 a, that is, a rectangular vibration element 20 a is configured. Note that the curvature in the θ direction in the 2D array transducer 16 is constant in the example shown in FIG. 1, but the curvature may be continuously changed along the θ direction.

  Each vibration element 20a is made of a material such as PZT or a composite material. An electrode layer (not shown) is formed on the front side and the rear side of each vibration element 20a. Incidentally, in FIG. 1, the illustration of the alignment member provided in front of the 2D array transducer 16, that is, in the Z direction, and the backing unit provided in the rear of the 2D array transducer 16 are omitted.

  A signal lead array 22 is provided behind the 2D array transducer 16. The signal lead array 22 includes a plurality of (that is, m × n) signal leads 22a individually connected to a plurality of vibration elements. Here, m is 64, for example, and n is 30, for example. The signal lead array 22 is preferably built in the backing unit.

  The probe head 10 has a casing (not shown), and a switch unit 24 is provided in the casing in addition to the 2D array transducer 16 described above. The switch unit 24 includes a plurality of switch circuits 26 corresponding to the plurality of vibration element arrays 20. Each switch circuit 26 functions as an aperture selection means. Each switch circuit 26 has one terminal row and the other terminal row, and k signal lines 30a are connected to one terminal row, and n signal leads 22a are connected to the other terminal row. The switch circuit 26 includes a switch row 28 that connects the k signal lines 30a and the n signal leads 22a to each other, and the switch row 28 includes k switches 28a. That is, the switch array 28 selects k vibration elements 20a arranged adjacent to each other among the n vibration elements 20a arranged in the θ direction, and these vibration elements 20a constitute a transmission / reception opening. Incidentally, in this embodiment, the transmission aperture and the reception aperture are configured to be the same, but the apertures may be different from each other.

  In the electronic linear scanning in the θ direction, the above-described switch row 28 functions for each vibration element row 20, and the opening is scanned from one end to the other end in the θ direction. In the present embodiment, the positions of the openings in each vibration element array 20 in the θ direction are the same, and an example of the openings is shown as hatching in FIG. That is, such an opening that expands two-dimensionally is scanned in stages in the θ direction. The pitch in this case is one vibration element in this embodiment, but it is of course possible to set a pitch for a plurality of vibration elements. Therefore, as a result of setting a partial opening for each vibration element row 20, channel reduction is achieved. That is, the number of signal lines can be reduced in the θ direction as compared with the case where the electronic sector method is applied. Incidentally, the above k is 10, for example.

  The probe cable 14 is constituted by a number of coaxial cables 32 corresponding to the plurality of vibration elements 20a constituting the opening shown by hatching in FIG. Specifically, it is configured by m × k coaxial cables 32.

  A first module 34 is provided on the apparatus main body 12 side of the probe cable 14. The first module 34 includes a plurality of circuit boards 36 provided corresponding to the plurality of coaxial cables 32, and each circuit board 36 has a transmitter 38 and a reception preamplifier 40. Further, a second module 42 is provided after the first module. The second module 42 is constituted by a plurality of circuit board pairs provided corresponding to the plurality of vibration element arrays 20, and each circuit board pair is constituted by a transmission board 42A and a reception board 42B.

  The transmission board 42A has a transmission timing control circuit 44, and the transmission timing control circuit 44 controls transmission operations of a plurality of transmitters 38 connected thereto. Specifically, the timing of the transmission signal generated in each transmitter 38 is controlled. The reception board 42B includes a plurality of delay units 46 provided corresponding to a plurality of (that is, k) reception signals to be input, and an adder 48 that adds the reception signals delayed by each delay unit 46, and have. In other words, a plurality of delay units 46 and adders 48 constitute a sub phase adjusting and adding circuit (first phase adjusting and adding circuit) 45. The sub phase adjusting and adding circuit 45 performs channel reduction for each vibration element array 20. The sub phase adjusting and adding circuit 45 corresponds to electronic linear scanning. Incidentally, the transmission timing control unit 44 is a circuit that supports both electronic linear scanning and electronic sector scanning. FIG. 1 shows only one first phasing and adding circuit set composed of m first phasing and adding circuits arranged in the X direction. In order to form a reception beam at the same time, a plurality of first phasing and adding circuit sets may be arranged. In this case, the reception aperture is common among the plurality of reception beams in the circumferential direction.

  A main phasing and adding circuit 50 is provided at the subsequent stage of the plurality of sub phasing and adding circuits 45. That is, the main phasing and adding circuit 50 corresponds to electronic sector scanning, and includes m delay units for delaying input m sub phasing and addition signals, and a delay by the m delay units. And an adder for adding the processed m signals. As a result, a final received signal after the phasing addition corresponding to the electronic linear scanning and the electronic sector scanning is obtained from the main phasing addition circuit 50. The received signal (echo data) is output to an image forming circuit after undergoing necessary signal processing, an ultrasonic image (for example, a three-dimensional image) is formed by the image forming circuit, and the ultrasonic image is not shown. Displayed on the instrument. Although only one main phasing and adding circuit 50 is shown in FIG. 1, a plurality of main phasing and adding circuits 50 are arranged in parallel to simultaneously form a plurality of reception beams in the X direction, that is, the cylindrical axis direction. It is desirable to do so. When a plurality of first phasing and adding circuit sets are provided as described above, one or a plurality of second phasing and adding circuits are provided for each first phasing and adding circuit set. When only one reception beam is formed in the cylindrical axis direction, the installation of the main phasing / adding circuit 50 is omitted, and the delay amount to be added to each first phasing / adding signal by the main phasing / adding circuit 50 is set in the previous stage. Each of the first phasing and adding circuits can be applied. In any case, a plurality of reception beams can be simultaneously formed in one or both of the circumferential direction and the cylindrical axis direction as necessary.

  In FIG. 1, reference numeral 51 denotes a transmission / reception control unit. The transmission / reception control unit 51 controls the operations of the plurality of transmission timing control circuits 44, the plurality of sub phase adjusting and adding circuits 45, and the main phase adjusting and adding circuit 50 described above. In particular, in the 2D array transducer 16, so that the ultrasonic beam steering and focusing are realized by the electronic sector method in the X direction, and the ultrasonic beam steering and focusing are realized by the electronic linear scanning in the θ direction, The transmission / reception control unit 51 performs control. Incidentally, necessary information is passed from the host controller to the transmission / reception control unit 51. Each phasing and adding circuit can be configured by an analog method or a digital method. When a plurality of sub phase adjusting and summing circuits are provided in the probe head 10, it is advantageous from the viewpoint of circuit scale to adopt an analog system. On the other hand, when a plurality of sub phasing and adding circuits 45 are installed in the apparatus main body 12, it is desirable that they are digital in view of signal processing accuracy. The main phasing and adding circuit 50 is generally a digital circuit.

  FIG. 2 is a perspective view showing the structure inside the probe head 10 shown in FIG. However, in FIG. 2, the illustration of the switch unit 24 and the like shown in FIG. 1 is omitted.

  As described above, the 2D array transducer 16 has a concave shape, that is, has a concave cylindrical surface shape curved in the θ direction. As described above, the 2D array transducer 16 has a plurality of vibration elements, which are separated from each other by the plurality of X grooves 52 and the plurality of θ grooves 54. A filling material or the like may be filled in the grooves 52 and 54. In that case, it is desirable to fill a member that does not cause acoustic crosstalk.

  A backing unit 56 is provided on the rear side of the 2D array transducer 16. The upper surface of the backing unit 56 has a concave cylindrical surface shape in accordance with the shape of the 2D array transducer 16. The backing unit 56 has a structure in which a plurality of backing plates 58 and a plurality of substrates 60 are alternately stacked. The backing plate 58 is made of a material that exhibits a backing action. The substrate 60 is configured as, for example, a flexible circuit substrate, and the substrate 60 has a plurality of signal leads 22 a patterned on the substrate body 62. Each signal lead 22a is electrically connected to the corresponding vibration element. In the backing unit 56, the signal lead array 22 penetrates it, and a signal line from each vibration element is drawn to the back side thereof. Incidentally, in FIG. 2, the ground layer and the like provided on the upper surface side of the 2D array transducer 16 are not shown. Matching elements 64 are provided on the front surface side, that is, the upper surface side of each vibration element constituting the 2D array transducer 16. The matching element 64 is a member for achieving acoustic impedance matching. A protective member 66 as a medium is provided on the front side of the plurality of matching elements 64. The protective member 66 has a shape that covers the entire 2D array transducer 16, and the front surface (biological contact surface) thereof is flat. However, the front surface of the protective member 66 may be a gentle convex surface, or the protective member 66 may exhibit the function of an acoustic lens. As shown in the drawing, the rear surface, that is, the lower surface of the protection member 66 has a convex shape, and the protection member 66 enters the recessed portion of the 2D array transducer 16. Therefore, acoustic matching between the living body and the 2D array transducer 16 can be improved even when the probe head 10 is in contact with the surface of the living body with such a configuration.

  FIG. 3 conceptually shows the operation of the 2D array transducer 16 described above. For example, when an opening 76 as shown in FIG. 3 is set, electronic sector scanning is applied using the opening 76, that is, the ultrasonic beam is scanned in the φ direction. That is, a plurality of ultrasonic beams 80-1 to 80-k are formed in the φ direction, and the scanning plane S is configured thereby. A three-dimensional space is formed by forming the scanning surface S while shifting the opening 76 step by step in the circumferential direction, that is, the θ direction. Incidentally, the ultrasonic beams constituting the scanning plane S when the opening 78 is set are denoted by reference numerals 82-1 to 82-k. Incidentally, in the case of forming each ultrasonic beam, the ultrasonic beam is focused in the electronic sector scanning direction according to the electronic sector scanning method, and the ultrasonic beam is steered at the same time. On the other hand, in the circumferential direction, that is, the θ direction, the ultrasonic beam is focused according to the electronic linear method. That is, focusing of the ultrasonic beam is performed in both directions, whereby a good beam profile can be obtained. Incidentally, beam steering by deflection control is not performed in the circumferential direction. However, as will be described later with reference to FIG. 6, by performing minute angle sector scanning, that is, beam deflection scanning at both ends in the circumferential direction, The three-dimensional space may be enlarged.

  As shown in FIG. 3, in this embodiment, the 2D array transducer 16 has a concave shape. For example, even when two ribs 70 and 72 exist, If the 2D vibrator 16 is properly positioned, the scanning surface S can be sufficiently swung through the gap, and even in this case, the ribs 70 and 72 do not become a hindrance. In other words, there is an advantage that a large three-dimensional space can be formed on the back side through the furrow.

  This will be further described with reference to FIG. In the present embodiment, the arc-shaped curvature center P of the 2D array transducer 16 is set to the normally assumed intercostal depth, that is, the normal intercostal depth when the probe head is in contact with the chest surface. The center of curvature corresponds to the cylindrical central axis 18 shown in FIG. Therefore, each ultrasonic beam passes through the center of curvature P and rotates or swings around the center. As will be described with reference to FIG. 5, the portion becomes a converging portion (intersection portion) or a constricted portion, so that the influence of the two ribs 70 and 72 can be minimized as described above. That is, by making the 2D array transducer 16 as described above, it is possible to form a three-dimensional space that can sufficiently cover the organs inside the ribs, that is, the heart, without being greatly affected by the ribs.

  Incidentally, in FIG. 4, the thickness of the ultrasonic beam is schematically shown. Here, the central axis of the ultrasonic beam 80-i corresponding to the opening 76 is indicated by L <b> 1 and is on the central axis. The focus point is indicated by F1. Similarly, the central axis for the ultrasonic wave 82-i corresponding to the opening 78 is represented by L2, and the focus point is represented by F2. Of course, each focus point can be varied along the beam axis as required. Here, the reception focus point is generally applied with the reception dynamic focus method, and is continuously scanned on the ultrasonic beam axis. The opening size in the circumferential direction may be variably set according to the situation. For example, when the size of the furrow is large, the opening may be made larger to increase the sound power and reception sensitivity. Alternatively, when the size of the ribs is small, the opening may be limited to be small, thereby reducing the influence of the ribs 70 and 72, that is, problems such as shadows generated on the image.

  FIG. 5 shows a conceptual diagram of the three-dimensional space 100 formed by the 2D array transducer 16 described above. The vertex of the scanning surface S is drawn so as to coincide with the center position of the 2D array transducer 16 in the electronic sector scanning direction. Actually, the entire area in the scanning direction of the electronic sector is used as an aperture, and ultrasonic waves are transmitted and received through the aperture. Incidentally, the movement trajectory of the vertex of the scanning surface S is represented by reference numeral 106. The three-dimensional space 100 is constituted by two portions 102 and 104 via a cylindrical central axis 18 corresponding to the swing axis of the scanning plane S in this embodiment. Here, the portion 102 is a space that mainly forms an echo data capturing space. Of course, the portion 104 may be included in a part of the three-dimensional image. As shown in the drawing, the vicinity of the cylindrical central axis 18 is a converging part, in other words, the part is a constricted part 90. As described in FIG. 4 and the like, there is such a constricted part, and by setting it between ribs, it is possible to capture echo data over a wide area in the living body without being affected by the ribs much It becomes.

  FIG. 6 shows another embodiment. The basic configuration is the same as that shown in FIGS. 1 and 2, but in the embodiment shown in FIG. 6, in addition to electronic linear scanning at both ends in the θ direction, ultrasonic beam deflection scanning (electronic sector). Equivalent to scanning). That is, as shown by # 1, the scanning surface is first deflected and scanned, and then the aperture is scanned according to the electronic linear scanning method as shown by # 2, and then the scanning surface is again scanned as shown by # 3. A deflection scan is performed. The scanning system switching positions are indicated by the respective scanning planes S1 to S4. In the first deflection scanning, a region θ1 is additionally formed, and thereafter a region indicated by θ2 is formed in the same manner as in the above embodiment. Thereafter, a region indicated by θ3 is additionally formed. Then, in addition to the three-dimensional space shown in FIG. 5, a space corresponding to the portion shown by hatching in FIG. 6 is added as a part of the data capture area.

  Therefore, since it is possible to form a larger three-dimensional echo data capturing space, it is desirable to apply the embodiment shown in FIG. 6 when the space between the ribs is wide, for example. Incidentally, in the embodiment shown in FIG. 6, the deflection scanning of the scanning surface is performed at both ends in the θ direction, but the deflection scanning may be performed only on one side thereof. Further, when there are three ribs, the deflection scanning may be applied intermittently in combination at an appropriate portion in the θ direction. That is, compound scanning combining electronic linear scanning and partial electronic sector scanning may be performed. Electronic sector scanning is applied to the X direction as in the above embodiment.

  In another configuration shown in FIG. 7, a medium 200 is provided on the living body 204 side of the array transducer 16. The medium 200 is provided on the living body side of the matching layer or as a matching layer. The upper surface of the medium 200 has a convex cylindrical surface, and the upper surface matches the shape of the array transducer. The lower portion of the medium 200 narrows downward corresponding to the beam scanning range, and the lower surface (contact surface to the living body surface 202) is flat. Of course, the lower surface may be gently expanded downward. It is desirable that the sound speed of the medium 200 and the sound speed of the living body 204 coincide with each other. In this case, the ultrasonic beam is not refracted at the boundary surface 206. In this case, the linear beam center axis (corresponding to the center line of the scanning surface) is represented by LA. On the other hand, when the sound speed in the medium and the sound speed in the living body are different, refraction occurs at the boundary surface 206 as shown by LB in FIG. This causes the up and down direction and the left and right direction of the converging part in the three-dimensional space to spread, and as a result, it is impossible to efficiently transmit and receive ultrasonic waves through the intercostal space.

  Therefore, it is desirable to perform beam azimuth correction, that is, beam deflection control for each beam address in association with electronic linear scanning in the circumferential direction. The beam central axis of the deflection-controlled ultrasonic beam is represented by LC in FIG. The beam center axis LC passes through the beam crossing portion P. If the beam deflection control is performed so that the central axis of the ultrasonic beam formed at each beam address passes through the beam crossing portion, the spread of the converging portion can be prevented and a good transmission / reception environment can be constructed. When electronic linear scanning combined with the above beam deflection control is performed, the size and position of each transmission / reception aperture are adaptively set for each ultrasonic beam. Further, when mapping each echo data to the three-dimensional storage space, beam refraction and beam deflection are considered.

  FIG. 8 shows still another embodiment. In FIG. 8, the same components as those shown in FIG.

  In this embodiment, a plurality of matching layers 300 are provided on the front side of the 2D array transducer 16. Specifically, the plurality of matching layers 300 are aligned in the X direction, which is the cylindrical central axis direction, and each matching layer 300 has a curved shape that continues along the θ direction, which is the circumferential direction. Each matching layer 300 is provided for each vibration element array 20 including a plurality of vibration elements aligned in the θ direction. In the embodiment shown in FIG. 2, matching elements are individually provided for each vibration element. However, in the embodiment shown in FIG. 8, each matching layer 300 has a plurality of matching elements connected in the θ direction. It is configured as That is, each matching layer 300 is an integrated member that extends in the θ direction. However, the plurality of matching layers 300 are separated from each other by the grooves 54 in the X direction.

  According to the above configuration, it is possible to eliminate or reduce the problem of frequency band deterioration that occurs when individual matching elements are miniaturized. As a result, for example, when the harmonic component in the received signal is imaged, the image quality can be improved. When a plurality of matching elements are connected to each other in the θ direction, the directivity angle characteristic decreases in the θ direction (although sound pressure and sensitivity decrease in the case of a large beam deflection angle), Basically, electronic linear scanning is applied and the ultrasonic beam is not greatly deflected. Therefore, even if the directivity angle characteristic is lowered, no practical problem occurs. On the other hand, in the X direction, since the plurality of matching layers 300 are separated from each other, the directivity characteristics in the X direction can be maintained. Even when the electronic sector scanning is applied in the X direction and the ultrasonic beam is largely deflected, sufficient transmission sound pressure can be obtained and sufficient reception sensitivity can be obtained.

  9 to 12 show modified examples. As shown in FIG. 9, a plurality of matching layers 302 and 304 that are stacked for each vibration element array may be provided. In the matching layer 306 shown in FIG. 10, a plurality of cuts 308 are formed at predetermined intervals. Each notch is formed in a position corresponding to between the vibration elements. The cuts can be formed from the upper surface side or from the lower surface side. Alternatively, a notch may be formed from both sides to leave a connecting portion that communicates between the matching elements in the middle of the thickness direction. By adjusting the cutting mode and the cutting amount, the frequency band characteristic and the directivity angle characteristic can be appropriately adjusted. If the matching layer is not completely cut in the thickness direction, the frequency band characteristics can be improved as compared with the case where the matching layer is completely cut. In the configuration example shown in FIG. 11, the filling material 310 is filled in the groove 52 between the vibration elements. The plugging material 310 is made of a material having an acoustic impedance that does not adversely affect the ultrasonic vibration in the vibration element and does not cause acoustic crosstalk. The cut material 308 shown in FIG. 10 may be filled with the same filling material. As shown in FIG. 12, when a plurality of matching layers 302 and 304 are provided in a stacked manner, the directivity characteristics can be improved by forming the groove 312 in the matching layer 304 close to the vibration element. .

It is a figure which shows the structure of the transmission / reception part in the ultrasonic diagnosing device which concerns on this invention. It is a perspective view which shows the structure of a probe head. It is a figure for demonstrating operation | movement of the 2D array vibrator | oscillator of this embodiment. It is a figure for demonstrating electronic linear scanning. It is a figure which shows the three-dimensional space formed with the 2D array transducer | vibrator which concerns on this embodiment. It is a figure for demonstrating the scanning system which concerns on other embodiment. It is a figure for demonstrating refraction of a beam, and its coping. It is a perspective view which shows the structure of the probe head which concerns on other embodiment. It is a figure which shows the matching layer laminated | stacked. It is a figure which shows the matching layer which has a some notch. It is a figure which shows the state with which the filling material was filled between vibration elements. It is a figure which shows the other example of the matching layer laminated | stacked.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 probe head, 12 apparatus main body, 14 probe cable, 16 2D array vibrator | oscillator, 20 vibration element row | line | column, 20a vibration element, 24 switch part, 26 switch circuit, 28 switch row | line | column, 32 coaxial cable, 34 1st module, 36 circuit Board, 38 Transmitter, 40 Preamplifier, 42 Second module, 44 Transmission timing control circuit, 45 Sub phasing addition circuit, 50 Main phasing addition circuit, 51 Transmission / reception control unit.

Claims (15)

An array vibrator composed of a plurality of vibration elements arranged in a concave cylindrical surface;
Transmitting / receiving means connected to the array transducer;
Including
The plurality of vibration elements are constituted by a plurality of vibration element arrays aligned in a cylindrical central axis direction,
Each of the vibrating element rows is composed of a plurality of vibrating elements aligned in the circumferential direction,
The transmission / reception means performs a first electronic scan as an electronic sector scan or an electronic linear scan in the cylindrical central axis direction, and performs a second electronic scan as an electronic linear scan in the circumferential direction ,
The transmitting / receiving means includes
A switching unit configured to set a concave cylindrical surface-shaped two-dimensional opening on the array transducer and scan the two-dimensional opening in the circumferential direction;
A transmission unit connected to the array transducer via the switching unit;
A receiving unit connected to the array transducer via the switching unit;
Including
At each set position of the two-dimensional opening in the circumferential direction, the ultrasonic beam is scanned in the cylindrical central axis direction while simultaneously focusing the ultrasonic beam in both the cylindrical central axis direction and the circumferential direction. Scanning plane is configured,
The scanning surface is scanned in the circumferential direction to form a three-dimensional space having a focusing portion.
An ultrasonic diagnostic apparatus. The apparatus of claim 1.
An ultrasonic diagnostic apparatus characterized in that means for variably setting the opening size in the circumferential direction of the two-dimensional opening is provided. The apparatus of claim 1 .
The ultrasonic diagnostic apparatus according to claim 1, wherein the converging part is a part including a cylindrical central axis. The apparatus of claim 1 .
2. The ultrasonic diagnostic apparatus according to claim 1, wherein the converging part is set at a position corresponding to or between the ribs of the human body. The apparatus of claim 1 .
The switching unit includes a plurality of switching circuits provided corresponding to the plurality of vibration element rows,
The receiving unit includes at least one first phasing and adding circuit set, and at least one second phasing and adding circuit provided for each first phasing and adding circuit set;
The first phasing and adding circuit set includes a plurality of first phasing and adding processes for executing a first phasing and adding process on a plurality of reception signals output from a plurality of vibration elements belonging to the opening for each of the vibration element rows. It consists of a phase addition circuit,
The second phasing addition circuit performs a second phasing addition process on a plurality of first phasing addition signals output from the first phasing addition circuit set corresponding to the second phasing addition circuit. Diagnostic device. The apparatus of claim 1 .
An ultrasonic diagnostic apparatus, wherein the array transducer and the switching unit are provided in a probe head. The apparatus of claim 5 .
An ultrasonic diagnostic apparatus, wherein the array transducer, the switching unit, the at least one first phasing and adding circuit set, and the transmission unit are provided in a probe head. The apparatus of claim 1.
An ultrasonic diagnostic apparatus, wherein an additional beam deflection scan for enlarging the three-dimensional space is performed at both ends in the circumferential direction following the second electronic scan. The apparatus of claim 1.
An ultrasonic diagnostic apparatus, wherein a medium for acoustic matching is provided on the living body side of the array transducer. The apparatus of claim 9 .
In the process of performing the second electronic scan in the circumferential direction, beam deflection control is applied to correct the beam direction to cope with the refraction of the ultrasonic beam at the interface between the medium and the living body. An ultrasonic diagnostic apparatus. The apparatus of claim 10 .
2. The ultrasonic diagnostic apparatus according to claim 1, wherein each ultrasonic beam intersects at a beam crossing site by the second electronic scanning with the beam deflection control in the circumferential direction. The apparatus of claim 1.
The ultrasonic diagnostic apparatus according to claim 1, wherein the first electronic scan is an electronic sector scan. An array vibrator composed of a plurality of vibration elements arranged in a concave cylindrical surface;
A plurality of matching layers provided on the upper surface side of the array transducer and aligned in the cylindrical central axis direction;
Transmitting / receiving means connected to the array transducer;
Including
The plurality of vibration elements are configured by a plurality of vibration element rows aligned in the cylindrical central axis direction,
Each of the vibrating element rows is composed of a plurality of vibrating elements aligned in the circumferential direction,
The transmission / reception means performs a first electronic scan as an electronic sector scan or an electronic linear scan in the cylindrical central axis direction, and performs a second electronic scan as an electronic linear scan in the circumferential direction,
The transmitting / receiving means includes
A switching unit configured to set a concave cylindrical surface-shaped two-dimensional opening on the array transducer and scan the two-dimensional opening in the circumferential direction;
A transmission unit connected to the array transducer via the switching unit;
A receiving unit connected to the array transducer via the switching unit;
Including
At each set position of the two-dimensional opening in the circumferential direction, the ultrasonic beam is scanned in the cylindrical central axis direction while the ultrasonic beam is focused in both the cylindrical central axis direction and the circumferential direction. A scanning plane is constructed,
The scanning surface is scanned in the circumferential direction to form a three-dimensional space having a converging portion,
Each matching layer is provided for each of the vibrating element rows, and each matching layer has a curved form that continues along the circumferential direction.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 13 .
The ultrasonic diagnostic apparatus, wherein the plurality of matching layers are divided from each other in the cylindrical central axis direction. The ultrasonic diagnostic apparatus according to claim 13 .
2. The ultrasonic diagnostic apparatus according to claim 1, wherein a plurality of cuts are formed in each matching layer in an arrangement corresponding to a plurality of inter-element grooves in each vibration element array.

Images