JP3905585B2 - Transesophageal ultrasound probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic probe that is used by being inserted into a body cavity and is capable of observing tomographic images of a number of tomographic planes.
[0002]
[Prior art]
As a conventional technique, there is known a multi-plane ultrasonic probe capable of easily observing ultrasonic tomographic images relating to a large number of tomographic planes without rotating the probe itself. A multi-plane ultrasonic probe rotates an ultrasonic scanning region (for example, a sector-shaped plane) to ultrasonically scan an arbitrary tomographic plane including a plurality of basic cross sections (to be described later). It collects acoustic tomographic images.
[0003]
When a means for scanning an ultrasonic wave is constituted by a vibrator array in which a plurality of ultrasonic vibrators are arranged in a one-dimensional direction, the rotation of the ultrasound scanning area physically moves the vibrator array. Realized by rotating. In addition, when the means for scanning the ultrasonic waves is constituted by an ultrasonic vibrator array in which a plurality of ultrasonic vibrators are arranged on a two-dimensional plane, similarly, the rotation of the scanning region is performed individually. This is realized by electrically switching and driving the sound wave vibrator.
[0004]
As an example of such a multi-plane ultrasonic probe, there is a multi-plane TEE ultrasonic probe (TEE: Transesophageal Echocardiography) which is inserted orally into a subject and observes the heart from the upper digestive tract including the esophagus and stomach. Since the multi-plane TEE ultrasonic probe can observe an image of a diagnostic site from the inside of a body cavity, it is not affected by an intercostal effect or an ultrasonic attenuation due to subcutaneous fat, and a clear image can be obtained. It is possible to observe or record a tomographic plane viewed from any direction.
[0005]
By the way, among the above-described multi-plane TEE ultrasonic probes, there is one that rotationally drives the ultrasonic transducer unit electrically by a motor provided in the probe base end or the endoscope operation unit. FIG. 8 is a diagram showing an example of such an electric drive type ultrasonic probe. In FIG. 8, 90 is a probe distal end portion, 91 is a probe guiding middle portion, and 92 is a probe proximal end portion. The probe base end 92 has a built-in motor and has switches 93 and 94 for controlling the rotation direction of the motor. When either one of these switches 93 or 94 is pressed, the ultrasonic transducer section 90 is reversed or forwardly rotated in the direction of arrow A or B as shown in FIG.
[0006]
By the way, as a rotational drive method of the ultrasonic transducer part, a pulley in the endoscope operation part and a pulley in the distal end part of the endoscope are connected by a wire, and the wire is pulled by rotating the knob of the operation part. A wire drive system for rotating an ultrasonic transducer (US Pat. No. 4,543,960), which transmits the rotation of a shaft disposed along the axial direction of a probe to a pulley on the transducer side via a worm gear. A shaft drive system (European Patent Publication No. 509,296) for rotating an ultrasonic transducer is known.
[0007]
Some have a mechanism for manually rotating the ultrasonic transducer, thereby collecting tomographic images relating to a required cross section. In this method, by manually rotating a knob or the like provided in the operation unit, the ultrasonic transducer at the distal end is rotated forward or backward via a driving force transmission means such as a wire.
[0008]
[Problems to be solved by the invention]
A conventional ultrasonic probe having an electric or manual rotation mechanism of the ultrasonic transducer as described above has the following problems. That is, in order to obtain the required cross section of the subject, it is necessary to repeat normal rotation or reverse rotation of the ultrasonic transducer many times to adjust to a predetermined angle, which causes a problem that operability is extremely poor. .
[0009]
For example, the electric rotating mechanism has an operation specification in which the rotation continues while the switch is pressed with a finger and the rotation stops when the finger is released from the switch. According to such an operation specification, fine adjustment is required to stop the rotation at a required cross-sectional position, and there is a problem that operability is poor.
[0010]
Accordingly, an object of the present invention is to provide an ultrasonic probe that can improve the operability by appropriately controlling the rotation of the ultrasonic transducer and shorten the diagnosis time.
[0011]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, the present invention uses the following means.
(1) The transesophageal ultrasonic probe according to the present invention includes a scanning unit capable of rotating an ultrasonic scanning region, a switch for giving an operation command, and scanning of the scanning unit according to the operation command given to the switch. A rotation control means for controlling the scanning means so that the scanning area rotates stepwise from a current rotation position of the area to a predetermined basic cross-section position among a plurality of basic cross-sections of the subject that form an angle of 45 degrees with each other; And a transesophageal ultrasonic probe.
(2) The transesophageal ultrasonic probe according to the present invention is the transesophageal ultrasonic probe according to (1), further comprising input means for inputting an external synchronization signal from an external device, and the rotation control means. By repeating the rotation control in accordance with the external synchronization signal input by the input means, the scanning area of the scanning means is rotated stepwise.
(3) The transesophageal ultrasonic probe according to the present invention is the transesophageal ultrasonic probe according to (1), further comprising setting means for setting a start position of a scanning region by the scanning means, and the rotation The control means controls the rotation of the scanning area so that the scanning area rotates stepwise from the start position set by the setting means.
(4) The transesophageal ultrasonic probe according to the present invention is provided with a plurality of concave portions at positions corresponding to a plurality of basic cross sections of a subject that forms an angle of 45 degrees with a scanning means capable of rotating an ultrasonic scanning region. A holding means for holding the scanning means so as to be rotatable integrally with the scanning means, an elastic member having a convex portion that fits into a concave portion of the holding means, and for rotating the holding means by manual operation. Rotation operation means, and the convex portion is fitted into the concave portion, whereby the scanning region is moved to any position of the plurality of basic cross sections with a click feeling. It is characterized by transmitting .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic system to which an ultrasonic probe according to the first embodiment of the present invention is attached. The ultrasound probe of this embodiment is a multi-plane transesophageal ultrasound probe that is orally inserted into the esophagus and collects, for example, a plurality of ultrasound tomographic images of the heart as a diagnostic object. The diagnosis referred to here means a diagnosis generally referred to as an ultrasonic heart diagnosis or echocardiography.
[0013]
The ultrasound diagnostic system shown in FIG. 1 includes an ultrasound probe in which a distal end portion 1 and a proximal end portion 2 are connected via a guiding middle portion (not shown), and an ultrasound diagnostic apparatus body 3. Yes. The ultrasonic diagnostic apparatus main body 3 has a power supply 31, and power from the power supply 31 is supplied to both the distal end portion 1 and the proximal end portion 2 of the ultrasonic probe.
[0014]
The distal end portion 1 is provided with an ultrasonic transducer portion 11 and an angle detector 12. The ultrasonic transducer unit 11 constitutes a transducer array in which a plurality of ultrasonic transducers are arranged in a one-dimensional direction, and can scan a scanning region in one depth direction by, for example, sector electronic scanning. The ultrasonic transducer unit 11 is attached so as to be rotatable around the central portion of the transducer array by the rotational force transmitted from the rotation drive motor 22 of the base end portion 2 through a wire (not shown). Thus, the scanning area is configured to be rotatable.
[0015]
The angle detector 12 is composed of a magnetic encoder such as an MR element (magnetoresistance effect element) or an optical encoder such as a potentiometer or volume or photoelectric sensor for detecting a change in resistance value. The rotation angle is detected and an angle signal is output. The output angle signal is supplied to the angle signal processing circuit 24 of the base end 2.
[0016]
The base end portion 2 includes an operation unit 21 including switches SW1 to SW4, a rotary drive motor 22, a motor control circuit 23, and an angle signal processing circuit 23. When the switches SW <b> 1 to SW <b> 4 are operated by the operator, the operation unit 21 outputs an operation command corresponding to the switches to the motor control circuit 23. The motor control circuit 23 controls the rotation of the rotary drive motor 22 by a predetermined control method based on the operation command output from the operation unit 21 and the angle signal output from the angle signal processing circuit 24. The angle signal processing circuit 24 processes the angle signal from the angle detector 12 of the tip 1 and sequentially outputs it to the motor control circuit 23.
[0017]
FIG. 2 is a view showing an appearance and a partial cross-section inside the ultrasonic probe of the present embodiment. As shown in the figure, the ultrasonic probe has a structure in which a distal end portion 1 and a proximal end portion 2 are connected via a bending guide portion 4 that can be bent. A plurality of electric cables for supplying power to the distal end portion 1 or transmitting various signals and a wire 5 for transmitting the rotational force of the ultrasonic transducer 11 are disposed inside the guiding middle portion 4.
[0018]
Inside the partial cross section of the base end portion 2, a pulley 6 and a rotational drive motor 22 for rotationally driving the ultrasonic transducer 11 via a wire 5 are arranged as shown in FIG. 2. Further, the switches SW1 to SW4 of the operation unit 21 are arranged on the surface of the base end part 2, and an operator (not shown) can operate these switches while holding the base end part 3 by hand. Yes. In FIG. 2, the switches SW1 to SW4 are shown as push button switches, but are not limited to this method. The switches SW1 to SW4 of the operation unit 21 are assigned the following functions.
[0019]
SW1: Ultrasonic vibrator forward switch SW2: Ultrasonic vibrator reverse switch SW3: Ultrasonic vibrator 45 ° step forward switch SW4: Ultrasonic vibrator 45 ° step reverse switch Multiplane transesophageal ultrasound As shown in FIG. 3, the rotation angle of the ultrasonic transducer of the probe (ultrasonic transducer angle) is generally determined from the angle of the plane perpendicular to the axis of the probe guiding middle 4 as 0 °. This shows how many times the scanning region S (vibrator array) of the transducer unit 11 has been rotated counterclockwise. In the figure, reference numeral 12 denotes an angle detector.
[0020]
When the ultrasonic probe is inserted into the esophagus, the ultrasonic transducer angle 0 ° is a cross-sectional tomographic image of the heart C perpendicular to the central axis of the guiding center (substantially parallel to the esophagus) 4 as shown in FIG. Is the angle of the tomographic plane. Here, a plurality of tomographic planes P obtained by sequentially rotating the scanning region S of the ultrasonic transducer section 11 by a predetermined angle counterclockwise, that is, tomographic planes P0 of 0 °, 45 °, 90 °, and 135 °. ~ P3 is considered to be a diagnostically important tomographic plane and is frequently observed during diagnosis. Here, the plurality of tomographic planes are referred to as basic cut (layer) planes. In FIG. 4, L is the left heart system of the heart C, and R is the right heart system of the heart C.
[0021]
0 °: cross-sectional plane of the heart perpendicular to the esophagus 45 °: short-axis slice plane of the heart 90 °: longitudinal slice plane 135 ° parallel to the esophagus 135 °: long-axis slice plane of the heart 180 °: esophageal Transverse tomographic plane of the heart perpendicular to it (mirror image of 0 ° slice plane)
Among these basic fault planes, the 0 ° (180 °) fault plane P0 and the 90 ° fault plane P2 indicate the transverse fault plane in the known biplane transesophageal ultrasound probe, and P2 is the vertical plane. (Longitudinal) Represents a fault plane and is considered particularly important.
[0022]
In this embodiment, when either one of the ultrasonic transducer 45 ° step forward switch SW3 or 45 ° step reverse switch SW4 is pressed, the current value is output based on the angle signal output from the angle signal processing circuit 24. The rotation drive motor 22 is controlled by the motor control circuit 23 so that the scanning region S rotates from the rotation position to the nearest basic cross-sectional position. For example, when the current rotation position of the scanning region S of the ultrasonic transducer unit 11 is at an angle of 45 °, when SW3 is pressed, the scanning region is moved to the nearest basic cross-sectional position, that is, 90 ° in this case. S is driven to rotate. Similarly, when SW4 is pressed, the scanning region S is rotationally driven to the most recent basic cross-sectional position, that is, the position of 0 ° in this case. In this embodiment, the automatic rotation control of the scanning region S to the position of the basic cross section is referred to as step forward rotation or step reverse rotation.
[0023]
The operations when the switches SW1 to SW4 are pressed are summarized as follows.
(1) Ultrasonic transducer forward rotation switch (SW1): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 rotates in the forward direction (that is, counterclockwise in FIG. 3). While the switch is kept pressed, the forward rotation operation is continued, and the forward rotation operation is stopped by releasing the finger from the switch (continuous forward rotation).
(2) Ultrasonic transducer reversing switch (SW2): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 rotates in the reverse direction (ie, clockwise in FIG. 3). While the switch is kept pressed, the reverse rotation operation is continued, and the reverse rotation operation is stopped by releasing the finger from the switch (continuous reverse rotation).
(3) 45 ° step forward rotation switch (SW3): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 starts to rotate in the forward direction, and the basic cross section 0 °, 45 °, 90 It stops automatically at the closest angular position among °, 135 °, and 180 °.
[0024]
For example, when the scanning region S is at a position of 0 ° in the initial state, every time this is pressed, an operation of 0 ° → 45 ° → 90 ° → 135 ° → 180 ° is performed.
Further, when the scanning region S is at a position of 30 ° in the initial state, every time this is pressed, an operation of 30 ° → 45 ° → 90 ° → 135 ° → 180 ° is performed.
(4) 45 ° step reversing switch (SW4): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 starts to rotate in the reverse direction, and the basic cross section is 0 °, 45 °, 90 °. , 135 °, 180 ° and automatically stops at the closest angular position.
[0025]
For example, when the scanning region S of the ultrasonic transducer unit 11 is at a position of 180 ° in the initial state, every time this is pressed, an operation of 180 ° → 135 ° → 90 ° → 45 ° → 0 ° is performed.
[0026]
When the scanning region S is at a position of 170 ° in the initial state, every time this is pressed, an operation of 170 ° → 135 ° → 90 ° → 45 ° → 0 ° is performed.
As described above, according to the first embodiment, the basic fault plane can be smoothly and promptly increased from 0 °, 45 °, 90 °, 135 °, 180 °, or 0 °, 90 °, 180 ° from any fault plane. The scanning region S of the sound wave oscillator unit 11 can be rotated. Therefore, the operability of the probe can be improved and the diagnosis time can be shortened. The step angle is not limited to 45 °, for example, 90 ° is the same.
[0027]
Here, various modifications of the first embodiment will be described.
(Modification 1)
Returning to FIG. The modified example 1 includes an interval circuit (not shown) that is connected to the motor control circuit 23 of the distal end portion 2 and gives a predetermined time interval signal, and the motor control circuit 23 corresponds to the time interval signal output from the interval circuit. Controls the rotation / stop of the rotary drive motor 22. Then, the rotation operation of the ultrasonic transducer as described above can be automatically repeated at predetermined time intervals, and the operation switches (SW1 to SW4) as described above are operated during the automatic rotation operation. Is unnecessary, and the burden on the operator is reduced. The interval circuit is arranged in either the distal end portion 2 or the ultrasonic diagnostic apparatus main body 3.
[0028]
(Modification 2)
In the second modification, the motor control circuit 23 controls the rotation / stop of the rotation drive motor 22 in synchronization with a synchronization signal (in this case, an ECG signal) from an external device other than the ultrasonic diagnostic apparatus such as an electrocardiograph. Then, the rotation operation of the ultrasonic transducer as described above can be automatically performed in consideration of the dynamics of the heart or other factors. Therefore, the same effect as the above (1) can be obtained, and more advanced diagnosis can be realized.
[0029]
(Modification 3)
In the third modification, the ultrasonic diagnostic apparatus main body 3 is provided with the same operation unit as the operation unit 21 including the switches SW1 to SW4. In this case, a person other than the operator holding the ultrasonic probe can control the rotation of the ultrasonic transducer, and various diagnostic forms can be realized.
[0030]
(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment, when targeting a patient whose heart position and angle with respect to the esophagus are slightly shifted, the ultrasonic transducer angles are set to 0 °, 45 °, 90 °, 135 °, and 180 °. Even so, a basic cross section useful for diagnosis may not be obtained. Therefore, in the present embodiment, one of the basic cross sections useful for diagnosis (actually, a tomographic plane slightly deviated from the tomographic planes having transducer angles of 0 °, 45 °, 90 °, 135 °, and 180 °). , And by moving 45 ° or 90 ° forward or reverse from this tomographic plane as a reference, it is quickly moved to another basic cross section. The schematic configuration of the present embodiment is the same as that described with reference to FIG. 1 in the first embodiment.
[0031]
That is, in the present embodiment, the start position of the scanning region S of the ultrasonic transducer unit 11 is set to an arbitrary position by the operator, and the scanning region S is set at a constant angle (for example, 45) with the start position set here as a starting point. The rotation of the scanning region S is controlled by the motor control circuit 23 so as to rotate only by (°).
[0032]
The operations when the switches SW1 to SW4 are pressed are summarized as follows. (1) Ultrasonic transducer forward rotation switch (SW1): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 rotates in the forward direction (that is, counterclockwise in FIG. 3). While the switch is kept pressed, the forward rotation operation is continued, and the forward rotation operation is stopped by releasing the finger from the switch (continuous forward rotation).
(2) Ultrasonic transducer reversing switch (SW2): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 rotates in the reverse direction (ie, clockwise in FIG. 3). While the switch is kept pressed, the reverse rotation operation is continued, and the reverse rotation operation is stopped by releasing the finger from the switch (continuous reverse rotation).
[0033]
The operator sets the start position of the scanning region S by appropriately operating the switches SW1 and SW2.
(3) 45 ° constant angle forward rotation switch (SW3): When this switch is pressed with a finger, the scanning area S of the ultrasonic transducer section 11 rotates in the positive direction by a constant angle of 45 ° and stops.
[0034]
For example, when the scanning region S of the ultrasonic transducer unit 11 is at the initial position of 30 °, the operation of 30 ° → 75 ° → 120 ° → 165 ° → 180 ° is performed each time this switch is pressed.
(4) 45 ° constant angle reversing switch (SW4): When this switch is pressed with a finger, the scanning region S of the ultrasonic transducer section 11 rotates in the reverse direction by a constant angle of 45 ° and stops.
[0035]
For example, when the scanning region S of the ultrasonic transducer section 11 is at the initial position of 170 °, the operation of 170 ° → 125 ° → 80 ° → 35 ° → ° is performed each time this switch is pressed.
[0036]
As described above, according to the second embodiment, a basic cross section (actually, a transducer useful for diagnosis) even when a patient whose heart position or angle with respect to the esophagus is slightly shifted is targeted. An ultrasonic tomographic image relating to a tomographic plane slightly deviated from the tomographic planes at angles of 0 °, 45 °, 90 °, 135 °, and 180 ° can be easily obtained.
[0037]
(Third embodiment)
Next, a third embodiment of the present invention will be described. In the first and second embodiments, it has been described that the ultrasonic transducer unit 11 is electrically driven and rotated by the rotation drive motor 22. However, in the third embodiment, the ultrasonic transducer unit 11 is manually operated. Is driven to rotate.
[0038]
FIG. 5 is a block diagram showing a configuration of an ultrasonic diagnostic system to which an ultrasonic probe according to a third embodiment of the present invention is attached, and FIG. 6 is a diagram showing an appearance and a partial cross-section inside the ultrasonic probe of this embodiment. FIG. 7 is a cross-sectional view showing the structure of the tip of the ultrasonic probe of this embodiment. The ultrasonic probe of this embodiment constitutes a multi-plane transesophageal ultrasonic probe as in the first and second embodiments, and the distal end portion 50 and the proximal end portion 60 are guided (not shown). It is connected and configured.
[0039]
The distal end portion 50 includes an ultrasonic transducer unit 11 similar to that in the first and second embodiments, an ultrasonic transducer case 51 to which the ultrasonic transducer unit 11 is attached, and a plurality of concave portions at predetermined positions. And a leaf spring 52 having a convex portion that fits into the concave portion of the ultrasonic transducer case 51 and exhibits elasticity.
[0040]
The base end portion 50 includes a rotation operation knob 61 and a pulley 62 that rotates together with the rotation operation knob 61. A wire 71 is stretched over the pulley 62, and the wire 71 is disposed in the guiding middle portion and is stretched over the ultrasonic transducer case 51 at the distal end portion 50. That is, when the operator manually rotates the rotary operation knob 61, this rotational force is transmitted to the ultrasonic transducer case 51 via the pulley 62 and the wire 71 (or a torque shaft), and the case 51 is rotationally driven. Is done. Therefore, similarly to the first embodiment, the scanning region S of the ultrasonic transducer section 11 can be rotated smoothly and rapidly.
[0041]
A plurality of concave portions of the ultrasonic transducer case 51 are provided in accordance with the positions (0 °, 45 °, 90 °, 135 °, 180 °) of the plurality of basic cross sections described above.
Therefore, each time the scanning region S of the ultrasonic transducer 11 rotates and moves to the basic cross-sectional position, the convex portion of the leaf spring 52 fits into the concave portion of the ultrasonic transducer case 51, and the movement to the basic cross-sectional position is the operator. Is communicated with a sense of click.
[0042]
Therefore, according to the third embodiment, the operability can be improved by appropriate rotation control of the ultrasonic transducer unit as in the first and second embodiments, and the diagnosis time can be shortened. Furthermore, since the electrical rotation mechanism is not provided, the configuration is simplified.
[0043]
The present invention is not limited to the embodiments described above, and can be implemented with various modifications. For example, the first embodiment and the second embodiment may be combined. In this case, the configuration is complicated, but more advanced rotation control of the ultrasonic transducer is realized.
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an ultrasonic probe that can improve operability by appropriate rotation control of the ultrasonic transducer and can shorten the diagnosis time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic system to which an ultrasonic probe according to a first embodiment of the present invention is attached.
FIGS. 2A and 2B are views showing an external appearance and a partial cross-section inside the ultrasonic probe according to the first embodiment. FIGS.
FIG. 3 is a schematic diagram showing a rotation angle of a scanning surface of the ultrasonic probe according to the first embodiment.
FIG. 4 is a schematic diagram showing the positional relationship between the ultrasonic tomographic plane of the ultrasonic probe according to the first embodiment and the heart.
FIG. 5 is a block diagram showing a schematic configuration of an ultrasound system to which an ultrasound probe according to a third embodiment of the present invention is attached.
FIG. 6 is a diagram showing an appearance and a partial cross-sectional view of an ultrasonic probe according to a third embodiment.
FIG. 7 is a cross-sectional view showing a structure of a distal end portion of an ultrasonic probe according to a third embodiment.
FIG. 8 is an external view of an ultrasonic probe according to a conventional example.
FIG. 9 is an external view of a distal end portion of an ultrasonic probe according to a conventional example.

Claims (4)

A scanning means capable of rotating an ultrasonic scanning region;
A switch for giving an operation command;
In accordance with an operation command given to the switch, the scanning region is stepped from a current rotational position of the scanning region of the scanning means to a predetermined basic cross-sectional position among a plurality of basic cross-sections of the subject that form an angle of 45 degrees with each other. Rotation control means for controlling the scanning means to rotate;
A transesophageal ultrasound probe comprising: It further comprises input means for inputting an external synchronization signal from an external device, and the rotation control by the rotation control means is repeated in synchronization with the external synchronization signal input by the input means, so that the scanning area of the scanning means The transesophageal ultrasonic probe according to claim 1, wherein the step rotates. Further comprising setting means for setting a start position of a scanning region by the scanning means;
2. The transesophageal ultrasound according to claim 1, wherein the rotation control unit controls the rotation of the scanning region so that the scanning region rotates stepwise from the start position set by the setting unit. Probe . A scanning means capable of rotating an ultrasonic scanning region;
A plurality of concave portions provided at positions corresponding to a plurality of basic cross sections of the subject that form an angle of 45 degrees with each other, and holding means for holding the scanning means so as to be rotatable integrally with the scanning means;
An elastic member having a convex portion that fits into the concave portion of the holding means;
Rotating operation means for rotating the holding means by manual operation,
The transesophageal tract is characterized by transmitting to the operator with a click feeling that the scanning region has moved to any position of the plurality of basic cross sections by fitting the convex portion into the concave portion. Ultrasonic probe .

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