JP2015116332A - Ultrasonic probe and ultrasonic diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic probe and an ultrasonic diagnostic device which can obtain an excellent ultrasonic image by improving symmetry of positive and negative transmission waveforms with limited power source capability.SOLUTION: A plurality of vibrators transmit and receive ultrasonic pulses. Transmission means transmits ultrasonic pulses to an object to be observed via the plurality of vibrators. Reception means receives ultrasonic echoes from the object to be observed via the plurality of vibrators. Adjustment means performs such adjustment that the shapes of transmission waveforms on a positive pole side and a negative pole side of the ultrasonic pulse transmitted from the transmission means become symmetric.

Description

  Embodiments described herein relate generally to an ultrasonic probe and an ultrasonic diagnostic apparatus that acquire an ultrasonic image from an observation object by scanning with an ultrasonic beam.

  In recent years, 2D array probes that have built-in electronic circuits and can transmit and receive by thousands of transducers (AM) and can display 3D ultrasound images in real time have been developed. Used for diagnosis. In the 2D array probe, in order to obtain an ultrasonic image with good resolution, the plurality of transducers are driven with a waveform having good symmetry between the positive and negative polarities, and the fundamental frequency component is erased from the obtained ultrasonic echo, A THI (Tissue Harmonic Imaging) method for extracting and imaging a high-frequency harmonic component is used.

  By the way, in order to obtain a waveform with good positive and negative symmetry, a powerful power source capable of supplying a sufficient current to the transmission circuit is required. However, since the conventional 2D array probe has a small case for accommodating a transmission circuit, a power supply, and the like, it cannot supply sufficient power to a circuit that generates positive and negative drive waveforms. As a result, the difference between the characteristics of the positive and negative transmission circuits becomes obvious and transmission waveforms having different symmetry are generated, and the fundamental frequency component is not sufficiently erased from the obtained ultrasonic echo. If imaging is performed in a state where the fundamental frequency component is not sufficiently erased from the obtained ultrasonic echo, an image having a poor resolution and affecting the diagnosis is acquired, and it is difficult to put it to practical use.

  In order to supply sufficient power, it is conceivable that the conventional 2D array probe improves the current supply capability by increasing the number of capacitors and lowering the impedance of the power supply. However, when the number of capacitors is increased to lower the impedance of the power source to improve the current supply capability, the number of capacitors of the transmission high-voltage power source becomes enormous and cannot be accommodated in the case.

JP 2008-220754 A

  An object of the present embodiment is to provide an ultrasonic probe and an ultrasonic diagnostic apparatus capable of improving the symmetry of positive and negative transmission waveforms with a limited power supply capability and obtaining a good ultrasonic image.

  The ultrasonic probe according to the present embodiment includes a plurality of transducers that transmit and receive ultrasonic pulses, a transmission unit that transmits ultrasonic pulses to the observation object via the plurality of transducers, and the plurality of transducers. Receiving means for receiving ultrasonic echoes from the object to be observed via, and adjusting means for adjusting the shapes of the transmission waveforms on the positive electrode side and the negative electrode side of the ultrasonic pulse transmitted from the transmitting means to be symmetric. It has.

1 is a circuit diagram showing an example of a configuration of an ultrasonic diagnostic apparatus including an ultrasonic probe according to an embodiment. Schematic which shows the asymmetry of the droop of a transmission waveform, and the asymmetry of a transmission waveform. The block diagram which shows an example of the transmission circuit of the ultrasonic probe shown in FIG. FIG. 3 is a circuit diagram showing a transmission circuit of the ultrasonic probe according to the first embodiment. The figure which shows the asymmetrical component detection circuit of a transmission waveform. The circuit diagram which shows the transmission circuit of the ultrasonic probe which concerns on 2nd Embodiment.

  Hereinafter, an ultrasonic probe and an ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a circuit diagram illustrating an example of a configuration of an ultrasonic diagnostic apparatus including the ultrasonic probe according to the embodiment.

  The ultrasonic diagnostic apparatus shown in FIG. 1 is an apparatus that acquires an ultrasonic image from an object to be observed 100 such as a heart, and includes an ultrasonic probe 1 and an apparatus main body 2.

  The ultrasonic probe 1 includes a transducer group 1-2, a pulser group (transmission drive circuit) 1-3, a preamplifier group 1-4, a TGC line 1-11, a subarray reception delay circuit 1-5, and a transmission delay circuit 1-6. And a probe connector 1-8.

  The transducer group 1-2 has a plurality of transducers arranged in an array in the probe handle 1-1.

  The pulsar group 1-3 is connected to the transducer group 1-2, and applies voltage pulses (drive signals) to a plurality of corresponding transducers according to the timing generated by the transmission delay circuit 1-6. .

  In the preamplifier group 1-4, the ultrasonic beam transmitted from the transducer group 1-2 is reflected at an interface having different acoustic impedance such as a boundary of a structure in the observed object 100, and Processing such as low noise amplification or buffering is performed to obtain a good transmission of the weak ultrasonic echo signal received by the transducer group 1-2 by obtaining information such as structure and motion.

  The TGC line 1-11 sets the gain of the preamplifier group 1-4 in common.

  The sub-array reception delay circuit 1-5 adds the output signals from the preamplifier group 1-4 with a delay time in groups of several channels, and reduces the number of output signal lines from the ultrasonic probe 1.

  The transmission delay circuit 1-6 generates timing for driving the transducer group 1-2 to generate an ultrasonic beam having a predetermined directivity.

  The probe connector 1-8 includes an electronic circuit group 1-9 and a control circuit 1-10.

  The electronic circuit group 1-9 performs additional processing of ultrasonic echo signals such as amplification, buffering, and band adjustment as necessary.

  The control circuit 1-10 generates a control signal to be transmitted to the subarray reception delay circuit group 1-5 and the transmission delay circuit 1-6 in the probe head based on a control signal transmitted from the apparatus main body 2 described later. .

  The probe handle 1-1 and the probe connector 1-8 are connected by a probe cable 1-7.

  The apparatus main body 2 includes a main body preamplifier group 2-4, a main body reception delay adding circuit 2-5, a signal processing unit 2-6, an image processing unit 2-7, and a display unit 2-8.

  The main body preamplifier group 2-4 amplifies the ultrasonic echo signal that has been subjected to the first reception delay addition processing in a group of several channels by the ultrasonic probe 1. The reception delay adding circuit 2-5 synchronizes the timings of the plurality of ultrasonic echo signals amplified by the main body preamplifier group 2-4. The signal processing unit 2-6 detects a plurality of ultrasonic echo signals and extracts envelopes of the plurality of ultrasonic echo signals. The image processing unit 2-7 performs coordinate conversion according to the cross section of the observation object 100, and performs gradation processing suitable for image display. The display unit 2-8 displays an ultrasonic image that has been subjected to coordinate conversion, gradation processing, and the like. Thereby, the ultrasonic diagnostic apparatus can display the form information (not shown) in the observed object 100 in real time.

  Further, the image processing unit 2-7 detects and processes the Doppler shift of the frequency of the ultrasonic beam due to the movement of blood cells, which is obtained by performing transmission and reception of ultrasonic waves with respect to the blood flow in the observed object 100. Are displayed on the display unit 2-8. Thereby, the ultrasonic diagnostic apparatus can display blood flow velocity information as a Doppler image (not shown).

  The apparatus main body 2 includes a main body control circuit 2-9 and an operation panel 2-10 for controlling the operation of each processing unit and transmitting control information to the control circuit 1-10 of the probe connector 1-8. Prepare.

  Further, the apparatus main body 2 is operated when an ultrasonic probe that does not incorporate an electronic circuit is connected, that is, when a vibrator in the ultrasonic probe is driven by the apparatus main body 2, and a main body transmission delay circuit 2-2 and a main body pulser. It has group 2-3.

  Here, portions related to transmission of the ultrasonic diagnostic apparatus will be described in detail.

  FIG. 2 is a block diagram illustrating an example of a transmission circuit of the ultrasonic diagnostic apparatus illustrated in FIG.

  2 includes a transmission delay circuit 3-1 (corresponding to the transmission delay circuit 1-6 or the main body transmission delay circuit 2-2 in FIG. 1), pulsers 3-21 to 2-2 n (the pulser group in FIG. 1). 1-3 or main body pulsar group 2-3) and a power supply unit 3-3.

  The pulsars 3-21 to 3-2 n apply voltage pulses (drive signals) to the corresponding transducers at timings based on the rate pulses output from the transmission delay circuit 3-1, respectively. The power supply unit 3-3 generates a high voltage pulse applied to the plurality of vibrators.

  Further, the circuit configuration of the transmission circuit will be described in detail.

(First embodiment)
In the first embodiment, by adjusting the capacitance of the bypass capacitor included in the power supply unit 3-3, the droop in which the peak value gradually decreases due to the continuation of the pulse train of the transmission waveform (see FIG. 3A). As for the phenomenon described above, the symmetry is improved between the transmission waveform on the positive electrode side and the transmission waveform on the negative electrode side.

  FIG. 4 is a circuit diagram illustrating a transmission circuit of the ultrasonic probe according to the first embodiment.

  As shown in FIG. 4, the capacitance is adjusted by connecting a plurality of capacitors having a value smaller than that of the bypass capacitor in parallel to the bypass capacitor of the power supply unit 3-3 of the transmission circuit. Here, since the adjustment to the power sources on both the positive and negative sides is complicated, it is performed on either the positive or negative power source. In the first embodiment, the adjustment is performed on the power source on the negative electrode side, but the adjustment on the positive electrode side can be similarly performed.

  First, the transmission circuit includes a positive-side transmission high-voltage power supply bypass capacitor 4-1 (hereinafter referred to as bypass capacitor 4-1) that forms a transmission waveform on the positive side of the ultrasonic pulse, and a transmission waveform on the negative side of the ultrasonic pulse. Negative side high-voltage power supply bypass capacitor 4-2 (hereinafter referred to as bypass capacitor 4-2) and positive-side and negative-side high-voltage power supply bypass capacitors forming positive and negative power sources from the drive stage And two main transistors for generating a high-voltage transmission waveform. Here, the electric capacity of the main bypass capacitor 4-2 connected to the negative power source VEE is made smaller than that of the bypass capacitor 4-1 connected to the positive power source VDD. A small-capacitance capacitor group 4-3 is arranged in parallel to the main bypass capacitor 4-2. For example, assuming that the capacity ratio of the bypass capacitor 4-1 on the positive electrode side is 10, the capacity ratio of the main bypass capacitor 4-2 on the negative electrode side is 5. In the small-capacitance capacitor group 4-3, capacitors having a capacitance ratio of 0.5, 1, 2, 4, etc. are connected in a ladder shape. By switching the number of capacitors connected in the small-capacitance capacitor group 4-3, it is possible to set the capacitance ratio of the entire bypass capacitor on the negative electrode side from 12.5 to 5. The small-capacitance capacitor group 4-3 is mounted on the flexible substrate 4-4 in a ladder shape, and one electrode side is connected in a pattern that curves outward. The adjustment of the electric capacity in this case is an adjustment cutting loop formed by a pattern in which the small-capacitance capacitor group 4-3 connected in a ladder shape is curved outward on the flexible substrate 4-4 while monitoring the transmission waveform. 4-5 are separated in order so that the symmetry between the transmission waveform on the positive electrode side and the transmission waveform on the negative electrode side is optimized. The flexible board 4-4 can be connected to the main bypass capacitor 4-2 on the negative electrode side with the flexible connector 4-6. With this configuration, the adjustment can be repeated by replacing the flexible board 4-4. It is possible to set a more optimal addition of the small-capacitance capacitor group 4-3.

  FIG. 5 is a diagram illustrating an asymmetric component detection circuit of a transmission waveform.

  The capacity adjustment is performed by obtaining monitoring information from the transmission waveform asymmetric component detection circuit shown in FIG. As shown in FIG. 5, a transmission waveform having a voltage as high as 200 V is generally stepped down to a voltage that can be easily processed by the attenuator 5-1, for example, several volts. After stepping down, based on the signal from the control circuit 1-10, a gated integrator 5-2 that integrates at an integral multiple of the transmission waveform period calculates the difference between the area of the positive waveform and the area of the negative waveform. The non-target component of the waveform is output as a voltage. The output value of the voltage is displayed on the display unit 2-8 of the apparatus main body 2 via the probe cable 1-7, and adjustment is performed so that the output value of the voltage is minimized. Thereby, it is possible to easily adjust the capacitance of the capacitor.

(Second Embodiment)
In the second embodiment, the symmetry of the transmission waveform on the positive electrode side and the transmission waveform on the negative electrode side is improved by adjusting the capability of the output stage of the drive circuit and changing the rise / fall time of the transmission waveform. (See FIG. 2 (b)).

  FIG. 6 is a circuit diagram illustrating a transmission circuit of the ultrasonic probe according to the second embodiment.

  As shown in FIG. 6, even when a plurality of small transistors are connected in parallel to the main transistor in the output stage of the transmission circuit to adjust the driving capability, the operation is performed for either the positive or negative main transistor. In the second embodiment, the output transistor 6-2 on the negative electrode side is performed, but the same can be performed on the positive electrode side.

  First, as in the first embodiment, the transmission circuit includes a bypass capacitor 4-1, a bypass capacitor 4-2 (in FIG. 6, illustration of the bypass capacitor 4-1 and the bypass capacitor 4-2 is omitted) and There are two main transistors that switch the positive and negative power sources from the positive and negative transmission high-voltage power supply bypass capacitors based on the drive signal from the drive stage and generate a high-voltage transmission waveform. Here, the capability of the main transistor 6-2 on the negative electrode side of the transmission circuit is set smaller than that of the main transistor 6-1 on the positive electrode side. A plurality of small transistor groups 6-3 are connected in parallel to the negative-side main transistor 6-2, and the drive signal from the drive stage is monitored by the correction gate 6-4 while monitoring the transmission waveform. 3 are sequentially supplied and turned on so that the symmetry between the transmission waveform on the positive electrode side and the transmission waveform on the negative electrode side is optimized. Also in the adjustment in this case, the transmission waveform described in the first embodiment is integrated at an integral multiple of the period and output as a voltage. The output value of the voltage is displayed on the display unit 2-8 of the apparatus main body 2 via the probe cable 1-7, and adjustment is performed so that the output value of the voltage is minimized.

  Further, even after the adjustment is automated and shipped, it is possible to cope with the problem by adjusting the parallel number of the small transistor groups 6-3. In addition, since the transmission waveform changes depending on the mode of ultrasonic image (B mode, color Doppler, etc.), transmission output, ultrasonic frequency, etc., the control circuit determines the number of small transistor groups 6-3 that are turned on under each of these conditions. It is possible to optimize the symmetry on the positive side and the negative side of the transmission waveform under each condition by storing it in a memory (not shown) in 1-10, reading it out and applying it.

  Here, in the ultrasonic diagnostic apparatus according to the second embodiment, an inspection device or the like is built in the ultrasonic probe 1, and a small transistor group is corrected by the correction gate 6-4 while monitoring the transmission waveform by the inspection device. 6-3 may be sequentially supplied and turned on so that the symmetry between the transmission waveform on the positive electrode side and the transmission waveform on the negative electrode side is optimized.

  According to the above configuration, the ultrasonic probes according to the first and second embodiments can make the transmission waveforms of positive and negative polarities in a state of good symmetry without increasing the number of capacitors of the transmission high-voltage power supply. Is possible.

  Therefore, the ultrasonic probe can improve the symmetry of positive and negative transmission waveforms even in a probe having a small shape and limited power supply capability, and can obtain a good ultrasonic image. In addition, an ultrasonic diagnostic apparatus having a function of improving the symmetry can be provided.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 100 ... Observed object (heart), 1 ... Ultrasonic probe, 1-1 ... Probe handle, vibrator group 1-2 ..., 1-3 ... Pulsar group (transmission drive circuit), 1-4 ... Preamplifier group, 1 -5 ... subarray reception delay circuit, 1-6 ... transmission delay circuit, 1-7 ... probe cable, 1-8 ... probe connector, 1-9 ... electronic circuit group, 1-10 ... control circuit, 1-11 ... TGC Line 2, apparatus body 2-1, body side probe connector, 2-2 body body transmission delay circuit, 2-3 body body pulser group, 2-4 body body preamplifier group, 2-5 body body reception delay adding circuit 2-6, signal processing unit, 2-7, image processing unit, 2-8, display unit, 2-9, main body control circuit, 2-10, operation panel, 4-1, high voltage power supply bypass for positive side transmission. Capacitor, 4-2 ... Negative side transmission high voltage power supply bypass capacitor, 4- ... correction capacitor group, 4-4 ... flexible sheet, 4-5 ... cutting loop for adjustment, 4-6 ... flexible connector, 5-1 ... attenuator, 5-2 ... integrator with gate, 6-1 ... positive side Main output transistor, 6-2... Negative side main output transistor, 6-3... Correction small transistor group, 6-4... Correction gate (switch).

Claims (9)

A plurality of transducers for transmitting and receiving ultrasonic pulses;
Transmitting means for transmitting an ultrasonic pulse to the object to be observed through the plurality of vibrators;
Receiving means for receiving ultrasonic echoes from the object to be observed through the plurality of transducers;
An ultrasonic probe comprising: adjusting means for adjusting the shape of the transmission waveform on the positive electrode side and the negative electrode side of the ultrasonic pulse transmitted from the transmission means to be symmetric. The transmission means includes
Positive power supply means for supplying power on the positive side of the ultrasonic pulse;
Negative electrode side power supply means for supplying power on the negative electrode side of the ultrasonic pulse;
The ultrasonic probe according to claim 1, further comprising: two main transistors that switch power supplies output from the positive and negative power supply means based on a drive signal from a drive stage.   The adjusting means has a capacity smaller than that of the first capacitor as a bypass capacitor in at least one of the positive electrode side and the negative electrode side power supply means, and depends on the number of second capacitors connected in parallel to the first capacitor, The ultrasonic probe according to claim 2, wherein the impedance of at least one of the positive electrode side and the negative electrode side power supply means is adjusted. It further comprises detection means for detecting a transmission waveform of the ultrasonic pulse,
The adjusting means is configured such that at least one of the two main transistors provided on the positive electrode side and the negative electrode side is smaller in size than the first transistor as the main transistor and is connected in parallel to the first transistor. Depending on the number of transistors, the drive capability of at least one of the positive-side and negative-side main transistors is adjusted so that the shapes of the transmission waveforms on the positive and negative sides of the ultrasonic pulse detected by the detection means are symmetric. The ultrasonic probe according to claim 2. A plurality of transducers for transmitting and receiving ultrasonic pulses;
Transmitting means for transmitting an ultrasonic pulse to the object to be observed through the plurality of vibrators;
Receiving means for receiving ultrasonic echoes from the object to be observed through the plurality of transducers;
Control means for controlling the transmission operation of ultrasonic pulses by the transmission means and the reception operation of ultrasonic echoes by the reception means;
An ultrasonic diagnostic apparatus comprising: an adjusting unit configured to adjust a shape of a transmission waveform on a positive electrode side and a negative electrode side of an ultrasonic pulse transmitted from the transmission unit to be symmetric. The transmission means includes
Positive power supply means for supplying power on the positive side of the ultrasonic pulse;
Negative electrode side power supply means for supplying power on the negative electrode side of the ultrasonic pulse;
The ultrasonic diagnostic apparatus according to claim 5, further comprising two main transistors that switch power supplies output from the positive-side and negative-side power supply means based on a drive signal from a drive stage.   The adjusting means has a capacity smaller than that of the first capacitor as a bypass capacitor in at least one of the positive electrode side and the negative electrode side power supply means, and depends on the number of second capacitors connected in parallel to the first capacitor, The ultrasonic diagnostic apparatus according to claim 6, wherein the impedance of at least one of the positive electrode side and the negative electrode side power supply means is adjusted.   The ultrasonic diagnostic apparatus according to claim 7, further comprising detection means for detecting a transmission waveform of the ultrasonic pulse. It further comprises detection means for detecting a transmission waveform of the ultrasonic pulse,
The adjusting means is configured such that at least one of the two main transistors provided on the positive electrode side and the negative electrode side is smaller in size than the first transistor as the main transistor and is connected in parallel to the first transistor. Depending on the number of transistors, the drive capability of at least one of the positive-side and negative-side main transistors is adjusted so that the shapes of the transmission waveforms on the positive and negative sides of the ultrasonic pulse detected by the detection means are symmetric. The ultrasonic diagnostic apparatus according to claim 6.

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