Ultrasonic diagnostic apparatus, drive signal generation method, and drive signal generation program

Abstract

To provide an ultrasonic diagnostic apparatus, a drive signal generation method, and a drive signal generation program capable of suppressing deterioration of a diagnostic image due to unnecessary radiation.SOLUTION: An ultrasonic diagnostic apparatus comprises: a drive signal generation unit which generates a drive signal based on a pulse signal for driving an ultrasonic probe; and a transmission unit which transmits the drive signal to the ultrasonic probe. Each of a plurality of half-wave sections constituting the pulse signal includes one or more transmission sections and one or more pause sections. The drive signal generation unit generates, as the drive signal, a modulated drive signal in which widths of at least two of the plurality of half-wave sections are made different from each other so that widths of the pause sections are different from each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an ultrasonic diagnostic apparatus, a driving signal generation method, and a driving signal generation program.

Background Art

[0002] Conventionally, an ultrasonic diagnostic apparatus that can perform an examination of the inside of a subject by transmitting ultrasonic waves toward the subject with an ultrasonic probe and receiving reflected waves from the subject has become widespread.

[0003] In an ultrasonic diagnostic apparatus, ultrasonic waves are generated by inputting a driving signal based on a pulse signal. For example, Patent Document 1 discloses an apparatus capable of making the duty ratio of a driving signal of an ultrasonic probe (ultrasonic wave generating means) variable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when a frequency component (high-frequency component) higher than the frequency band of the ultrasonic probe is included in the driving signal, there is a possibility that the high-frequency component of the electromagnetic wave based on the driving signal is emitted as unnecessary radiation. When unnecessary radiation exceeding the standard value of the EMC test is emitted, it is necessary to limit the driving voltage to the apparatus. Limiting the driving voltage to the apparatus may lead to deterioration of the diagnostic image based on ultrasonic waves.

[0006] An object of the present invention is to provide an ultrasonic diagnostic apparatus, a driving signal generation method, and a driving signal generation program capable of suppressing deterioration of a diagnostic image due to unnecessary radiation.

Means for Solving the Problems

[0007] The ultrasonic diagnostic apparatus according to the present invention includes a drive signal generation unit that generates a drive signal based on a pulse signal for driving an ultrasonic probe, and a transmission unit that transmits the drive signal to the ultrasonic probe. Each of a plurality of half-wave intervals constituting the pulse signal includes one or more transmission intervals and one or more rest intervals, and the drive signal generation unit generates, as the drive signal, a modulated drive signal in which at least two widths of the plurality of half-wave intervals are made different so that the widths of the rest intervals are different from each other.

[0008] The drive signal generation method according to the present invention is a drive signal generation method in an ultrasonic diagnostic apparatus, including generating a drive signal based on a pulse signal for driving an ultrasonic probe, and transmitting the drive signal to the ultrasonic probe. Each of a plurality of half-wave intervals constituting the pulse signal includes one or more transmission intervals and one or more rest intervals, and in generating the drive signal, a modulated drive signal in which at least two widths of the plurality of half-wave intervals are made different so that the widths of the rest intervals are different from each other is generated as the drive signal.

[0009] The drive signal generation program according to the present invention is a drive signal generation program in an ultrasonic diagnostic apparatus, which causes a computer to generate a drive signal based on a pulse signal for driving an ultrasonic probe, and transmit the drive signal to the ultrasonic probe. Each of a plurality of half-wave intervals constituting the pulse signal includes one or more transmission intervals and one or more rest intervals, ​​​The process of generating the drive signal includes a process of generating, as the drive signal, a modulated drive signal in which at least two of the plurality of half-wave sections have different widths so that the widths of the pause sections are different from each other. [Effects of the Invention]

[0010] According to the present invention, it is possible to suppress deterioration of diagnostic images due to unnecessary radiation. [Brief explanation of the drawings]

[0011]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Fig. 1 is a diagram showing the schematic configuration of an ultrasound diagnostic device 100 according to an embodiment of the present invention. Fig. 2 is a block diagram showing the main functional configuration of the ultrasound diagnostic device 100.

[0013] 1, the ultrasound diagnostic device 100 includes an image generating device 10 and an ultrasound probe 30. The image generating device 10 is provided with an operation input unit 18 and a display unit 19, and is connected to the ultrasound probe 30 via a cable 40.

[0014] The image generating device 10 outputs a drive signal for transmitting ultrasound waves to the ultrasound probe 30 based on an input operation by the operator via the operation input unit 18. The image generating device 10 also acquires a received signal relating to the reception of reflected ultrasound waves from the ultrasound probe 30, performs various processes, generates an ultrasound image, and displays it on the display unit 19.

[0015] As shown in FIG. 2, the image generating device 10 includes a waveform determining unit 11, a drive signal generating unit 12, a received signal processing unit 13, a transmitting / receiving unit 14, a control unit 15, an image processing unit 16, a memory unit 17, an operation input unit 18, and a display unit 19.

[0016] The waveform determination unit 11 determines the waveform of a drive signal (pulse signal) for driving the ultrasonic probe 30. The waveform determination unit 11 determines a drive waveform that matches the transmission characteristics of the ultrasonic probe 30. The waveform determination unit 11 determines a drive waveform that corresponds to a display mode using waveform information stored in advance in a waveform information storage unit 111. The waveform information storage unit 111 stores waveform information in which candidates for transmission voltages for each display mode are associated in advance with transmission waveforms that correspond to those transmission voltages.

[0017] The drive signal generation unit 12 generates a drive signal based on the waveform determined by the waveform determination unit 11 and the transmission conditions. The transmission conditions are stored in, for example, the storage unit 17, or are input by an operator via the operation input unit 18. The transmission conditions include, for example, a transmission aperture, a focal position, a transmission interval, and a transmission voltage. Details of the drive signal generated by the drive signal generation unit 12 will be described later.

[0018] The drive signal generation unit 12 includes, for example, a clock generation circuit, a pulse generation circuit, a pulse width setting unit, and a delay circuit. The clock generation circuit is a circuit that generates a clock signal for determining the transmission timing and transmission frequency of a pulse signal. The pulse generation circuit is a circuit that generates a rectangular wave pulse of a transmission voltage based on transmission conditions. The pulse width setting unit sets the pulse width of the pulse output from the pulse generation circuit based on the transmission waveform included in the transmission conditions. The rectangular wave pulse generated by the pulse generation circuit is separated into different wiring paths for each individual vibrator 31 of the ultrasonic probe 30 before or after being input to the pulse width setting unit. The delay circuit is a circuit that delays and outputs each of the delay times set for these wiring paths according to the timing of transmitting the generated rectangular wave pulse to each vibrator 31.

[0019] The pulse generation circuit can generate a rectangular wave pulse having a plurality of frequencies and having three values (+V, 0, -V) or five values (+V1, +V2, 0, -V2, -V1).

[0020] Also, it is desirable that the pulse generation circuit can arbitrarily change at least one of the rise time and fall time of the generated pulse. The pulse generation circuit preferably arbitrarily changes at least one of the rise time and fall time according to the display mode.

[0021] A specific example will be described. When the display mode is the B mode, it is preferable to make the rise time and fall time relatively short and control them finely. On the other hand, when the display mode is the pulsed Doppler mode, color Doppler mode, and CWD (continuous wave doppler) mode, different from the B mode, frequencies in a limited low-frequency range are used. In this case, since the frequency components in the high-frequency range become factors for unnecessary heat generation and electromagnetic wave regulation, it is preferable to make the rise time and fall time relatively long to suppress the generation of harmonics.

[0022] The receiving signal processing unit 13 is a circuit that acquires the received signal input from the ultrasonic probe 30 according to the control of the control unit 15. The receiving signal processing unit 13 includes, for example, an amplifier, an A / D conversion circuit, and a phased addition circuit. The amplifier is a circuit that amplifies the received signal corresponding to the ultrasonic waves received by each vibrator 31 of the ultrasonic probe 30 at a predetermined amplification factor set in advance. The A / D conversion circuit is a circuit that converts the amplified received signal into digital data at a predetermined sampling frequency. The phased addition circuit is a circuit that gives a delay time to the received signal after A / D conversion for each wiring path corresponding to each vibrator 31 to adjust the phase, and adds (phased addition) these to generate beam data.

[0023] When the transmitting and receiving unit 14 oscillates ultrasonic waves from the vibrator 31 based on the control of the control unit 15, the transmitting and receiving unit 14 transmits the drive signal generated by the drive signal generation unit 12 to the vibrator 31 (ultrasonic probe 30). When the transmitting and receiving unit 14 acquires the signal related to the ultrasonic wave emitted by the vibrator 31, the transmitting and receiving unit 14 outputs the received signal to the receiving signal processing unit 13. The transmitting and receiving unit 14 corresponds to the "transmitting unit" of the present invention.

[0024] The control unit 15 includes a CPU 151 (Central Processing Unit), an HDD 152 (Hard Disk Drive), a RAM 153 (Random Access Memory), and the like. The CPU 151 reads out various programs stored in the HDD 152, expands them in the RAM 153, and comprehensively controls the operations of each part of the ultrasonic diagnostic apparatus 100 according to the expanded programs. The HDD 152 stores the control program and various processing programs for operating the ultrasonic diagnostic apparatus 100, various setting data, image files generated by the ultrasonic diagnostic apparatus 100, and the like. These programs and setting data may be stored in a non-volatile memory such as a flash memory, in addition to the HDD 152, so that they can be read, written, and updated. The RAM 153 is a volatile memory such as SRAM or DRAM, provides a working memory space for the CPU 151, and stores temporary data. It can be said that the ultrasonic diagnostic apparatus 100 having the control unit 15 is a kind of computer.

[0025] The image processing unit 16 performs arithmetic processing for generating an ultrasonic image based on the received ultrasonic data. This ultrasonic image includes image data to be displayed in real time on the display unit 19, a series of video data, still image data of a snapshot, and the like. Note that this arithmetic processing may be performed by the CPU 151.

[0026] The storage unit 17 is, for example, a volatile memory such as a DRAM (Dynamic Random Access Memory). Alternatively, it may be various non-volatile memories capable of high-speed rewriting. The storage unit 17 stores various data, programs, etc. necessary for the operation of the ultrasonic diagnostic apparatus 100.

[0027] Further, the storage unit 17 stores the image data of the ultrasonic image for real-time display processed by the image processing unit 16 in frame units. The image data stored in the storage unit 17 is read out according to the control of the control unit 15, transmitted to the display unit 19, or output to the outside of the ultrasonic diagnostic apparatus 100 via a communication unit (not shown). At this time, when the display method of the display unit 19 is a television method, a DSC (Digital Signal Converter: not shown) may be provided between the storage unit 17 and the display unit 19, and output after the scanning format is converted.

[0028] The operation input unit 18 includes a push button switch, a keyboard, a mouse, a touch pad, or a track ball, or a combination thereof, and converts the input operation of the operator into an operation signal and outputs it to the control unit 15. The touch pad as the operation input unit 18 may be superimposed on the display unit 19 to form a touch panel.

[0029] Display unit 19 includes a predetermined display screen and a drive unit for driving it. The predetermined display screen is one of various display methods, such as an LCD (Liquid Crystal Display), an organic EL (Electro-Luminescence) display, an inorganic EL display, a plasma display, or a CRT (Cathode Ray Tube) display. Display unit 19 generates a drive signal for the display screen (each display pixel) in accordance with a control signal output from CPU 151 and image data generated by image processing unit 16. Display unit 19 then displays on the display screen menus and statuses related to ultrasound diagnosis, as well as measurement data such as ultrasound images based on received ultrasound.

[0030] The operation input unit 18 and the display unit 19 may be provided integrally with the housing of the image generating device 10, or may be attached externally via a USB cable or the like. Furthermore, if the image generating device 10 is provided with an operation input terminal and a display output terminal, conventional peripheral devices for operation and display may be connected to these terminals for use.

[0031] The ultrasonic probe 30 oscillates and transmits (emits) ultrasonic waves (for example, about 1 to 30 MHz) to a subject such as a living organism. The ultrasonic probe 30 also functions as an acoustic sensor that receives reflected waves (echoes) of the transmitted ultrasonic waves reflected by the subject and converts them into electrical signals. The ultrasonic probe 30 includes a transducer array 310 that is an array of multiple transducers 31 that transmit and receive ultrasonic waves.

[0032] The oscillator array 310 is an array of a plurality of oscillators 31 each including a piezoelectric element having a piezoelectric body and electrodes provided at both ends of the piezoelectric body where charges appear due to deformation (expansion and contraction) of the piezoelectric body. When a voltage pulse (driving signal) is supplied to the oscillator 31, the piezoelectric body deforms according to the electric field generated in each piezoelectric body, and ultrasonic waves are transmitted. Further, when ultrasonic waves in a predetermined frequency band are incident on the oscillator 31, the thickness of the piezoelectric body fluctuates (vibrates) due to the sound pressure, and charges corresponding to the amount of the fluctuation appear at both ends in the thickness fluctuation direction of the piezoelectric body. Charges corresponding to the amount of the charges are induced on the electrodes at both ends of the piezoelectric element.

[0033] The oscillator array 310 of the ultrasonic probe 30 includes, for example, about a hundred to several hundred oscillators 31 arranged in a one-dimensional array in a predetermined oscillator array direction. Alternatively, the oscillators 31 may be arranged in a direction orthogonal to the oscillator array direction to form a two-dimensional array. Also, the number of oscillators 31 may be arbitrarily set.

[0034] The ultrasonic probe 30 transmits ultrasonic waves from a set of consecutive oscillators 31 among these oscillators 31 based on the driving signal from the driving signal generation unit 12. Then, each time ultrasonic waves are generated, the set of oscillators 31 that transmit ultrasonic waves is shifted by a predetermined number of oscillators 31 in the oscillator array direction, thereby performing scanning in the scanning direction SD (see FIG. 2) parallel to the oscillator array direction. Also, as the ultrasonic probe 30, any of various scanning methods may be adopted. The scanning methods include various electronic scanning methods such as a linear electronic scanning method, a sector electronic scanning method, and a convex electronic scanning method, and a linear scanning method, a sector scanning method, an arc scanning method, a radial scanning method, etc.

[0035] Further, this ultrasonic diagnostic apparatus 100 may be configured to be able to connect any of a plurality of different ultrasonic probes 30 according to the diagnostic object to the image generation apparatus 10 and use them.

[0036] One end of the cable 40 has a connector (not shown) with the image generation apparatus 10, and the ultrasonic probe 30 is configured to be detachable from the image generation apparatus 10 by this cable 40.

[0037] Next, the details of the drive signal generated by the drive signal generation unit 12 will be described.

[0038] In the present embodiment, the drive signal generation unit 12 generates a modulation drive signal (see, for example, FIG. 3A) in which each of a plurality of half-wave intervals constituting a pulse signal for driving the ultrasonic probe 30 includes one or more transmission intervals and one or more rest intervals.

[0039] A half-wave interval is an interval corresponding to a half-wavelength in the pulse signal. A transmission interval is an interval that becomes the high period of the pulse signal (including the high period on the + side and the high period on the - side). A rest interval is an interval that becomes the low period of the pulse signal.

[0040] By setting such a rest interval, it is possible to adjust the intensity level of the ultrasonic wave without changing the period of the drive signal. For example, the lower the intensity level of the ultrasonic wave is set, the longer one rest interval is set.

[0041] FIG. 3A shows an example in which a half-wave interval has one transmission interval and one rest interval. FIG. 3B shows an example in which a half-wave interval has two transmission intervals and two rest intervals.

[0042] Specifically, the drive signal generation unit 12 generates a drive signal having a plurality of half-wave intervals including a first half-wave interval, a second half-wave interval, and a third half-wave interval, each having a different width. The widths of the rest intervals of the first half-wave interval, the second half-wave interval, and the third half-wave interval are different from each other. In other words, the drive signal generation unit 12 generates a drive signal in which at least two of the plurality of half-wave intervals have different widths so that at least the widths of the rest intervals are different from each other.

[0043] The first half-wave section is the section with the longest pause section width among the three half-wave sections. The second half-wave section is a section with a width wider than the first half-wave section and corresponding to the transmission frequency of the ultrasound probe 30. The third half-wave section is a section with a width wider than the second half-wave section and is the section with the shortest pause section width. The transmission frequency of the ultrasound probe 30 is a frequency within the frequency band of the ultrasound probe 30, and is a frequency set for transmission in the ultrasound diagnostic device 100. The width of the first half-wave section, the width of the second half-wave section, and the width of the third half-wave section each correspond to a frequency within the frequency band of the ultrasound probe 30.

[0044] 3A and 3B, the first two half-wave sections are the first half-wave sections. The next two half-wave sections are the second half-wave sections. The last two half-wave sections are the third half-wave sections. In other words, the time position of the second half-wave section is between the time positions of the first half-wave section and the third half-wave section.

[0045] Depending on the combination of the width of the pause interval and the width of the transmission interval, the drive signal may contain frequency components (high-frequency components) higher than the frequency band of the ultrasound probe 30. When the drive signal contains high-frequency components, the intensity of the high-frequency components increases in a drive signal composed of multiple half-waves with the same width, and the high-frequency components of the electromagnetic waves based on the drive signal may be emitted as unwanted radiation. If unwanted radiation is emitted that exceeds the EMC test standard, it becomes necessary to limit the drive voltage of the device. Limiting the drive voltage of the device may lead to deterioration of ultrasound-based diagnostic images.

[0046] In this embodiment, the pause interval of the first half-wave interval is shorter than the pause interval of the second half-wave interval, which shifts the intensity level of the signal at each frequency outside the frequency band of the ultrasonic probe 30. As a result, it is possible to weaken the signal intensity outside the frequency band compared to the case of the same half-wave interval.

[0047] Also, since the pause interval in the third half-wave interval is longer than the pause interval in the second half-wave interval, similarly, outside the frequency band of the ultrasonic probe 30, the intensity levels of the signals at each frequency shift. As a result, it becomes possible to weaken the signal intensity outside the frequency band compared to the case of the same half-wave interval.

[0048] By these means, it becomes possible to reduce the overall level of the signal intensity in the range exceeding the frequency band of the ultrasonic probe 30. As a result, it is possible to reduce the emission of unnecessary radiation of high-frequency components caused by the drive signal containing high-frequency components, and thus suppress the degradation of the diagnostic image.

[0049] Also, the total period of the drive signal including the first half-wave interval, the second half-wave interval, and the third half-wave interval is the same as the period when all of the plurality of half-wave intervals are the second half-wave interval. In other words, the sum of the width of the first half-wave interval, the width of the second half-wave interval, and the width of the third half-wave interval is three times the width of the second half-wave interval.

[0050] By doing so, the frequency corresponding to the modulated drive signal as a whole can be adjusted to the frequency corresponding to the second half-wave interval. As a result, the ultrasonic wave transmitted from the ultrasonic probe 30 can be made as desired.

[0051] Also, the change widths of the first half-wave interval and the third half-wave interval in the modulated drive signal with respect to the second half-wave interval (transmission frequency interval) are set to be, for example, a predetermined value times or more of the transmission frequency. The predetermined value can be set to an appropriate value by experiments, simulations, etc., such as 20.

[0052] Also, the waveform information of the modulated drive signal may be stored in advance in the waveform information storage unit 111. Also, when the waveform information of the modulated drive signal is not stored in the waveform information storage unit 111, the drive signal generation unit 12 may newly generate a modulated drive signal based on the waveform information stored in the waveform information storage unit 111.

[0053] Next, a verification experiment by the ultrasonic diagnostic apparatus 100 according to the present embodiment will be described. As an example, each half-wave section in the drive signal includes two transmission sections. The frequency corresponding to the width of the second half-wave section is set to a predetermined frequency (for example, 6 MHz). The frequency corresponding to the width of the first half-wave section is set to a frequency higher than the predetermined frequency, and the frequency corresponding to the width of the third half-wave section is set to a frequency lower than the predetermined frequency.

[0054] Further, as a comparative example, the drive signal is set such that all half-wave sections correspond to the width of the second half-wave section in the example. Also, the experimental conditions in the ultrasonic diagnostic apparatus 100 may be set to arbitrary conditions such that, in the comparative example, as shown in FIG. 4, for example, the level of the signal intensity outside the frequency band of the ultrasonic probe 30 is relatively high.

[0055] FIG. 5 is a diagram showing the experimental results in the example. As shown in FIG. 5, in the example, it can be confirmed that, compared with the comparative example, the level of the signal intensity is lower in the vicinity of the frequencies where the levels of the signal intensity outside the frequency band are the plurality of peak points P1 to P12 in the comparative example. That is, in the present embodiment, it can be confirmed that the level of the signal intensity is reduced as a whole in the range exceeding the frequency band of the ultrasonic probe 30.

[0056] According to the present embodiment configured as described above, the drive signal generation unit 12 generates, as a drive signal, a modulated drive signal in which at least two widths of a plurality of half-wave sections are made different so that the widths of the rest intervals are different from each other. Specifically, the drive signal generation unit 12 generates a modulated drive signal including a first half-wave section, a second half-wave section having a width wider than the width of the first half-wave section, and a third half-wave section having a width wider than the width of the second half-wave section.

[0057] By doing so, the high-frequency components in each half-wave interval can be shifted, so that it is possible to reduce the overall level of the signal intensity in a range exceeding the frequency band of the ultrasonic probe 30. As a result, it is possible to reduce the emission of unnecessary radiation of high-frequency components caused by the inclusion of high-frequency components in the drive signal, and thus suppress the deterioration of the diagnostic image.

[0058] Also, the width of the second half-wave interval is a width corresponding to the transmission frequency of the ultrasonic probe 30, and the sum of the width of the first half-wave interval, the width of the second half-wave interval, and the width of the third half-wave interval is three times the width of the second half-wave interval.

[0059] Thereby, the frequency corresponding to the drive signal can be adjusted to the frequency corresponding to the second half-wave interval as a whole. As a result, the ultrasonic wave transmitted from the ultrasonic probe 30 can be made as desired.

[0060] In the above embodiment, the temporal position of the second half-wave interval is after the temporal position of the first half-wave interval and before the temporal position of the third half-wave interval. However, the present invention is not limited to this. For example, as shown in FIG. 6, the temporal position of the second half-wave interval may be after the temporal position of the third half-wave interval and before the temporal position of the first half-wave interval.

[0061] Also, in the above embodiment, the drive signal generation unit 12 generates a drive signal that repeats each of the first half-wave interval, the second half-wave interval, and the third half-wave interval twice. However, the present invention is not limited to this. For example, as shown in FIG. 7, the drive signal generation unit 12 may generate a drive signal that repeats each of the first half-wave interval, the second half-wave interval, and the third half-wave interval three times. However, regarding the number of times of repeating the same half-wave interval, it is preferably set to an arbitrary number of times (for example, 4 times) or less in consideration of the number of half-wave intervals of the entire drive signal.

[0062] Further, in the above embodiment, the drive signal generation unit 12 generated a drive signal that repeated each of the half-wave intervals a plurality of times, but the present invention is not limited to this. For example, as shown in FIG. 8, the drive signal generation unit 12 may generate a drive signal that repeats a group of intervals including one each of the first half-wave interval, the second half-wave interval, and the third half-wave interval.

[0063] Also, in the above embodiment, the modulation drive signal was composed of three half-wave intervals, but the present invention is not limited to this. For example, the modulation drive signal may include three or more half-wave intervals. In this case, the modulation drive signal may be, for example, a drive signal with different half-wave interval widths such that the width of the half-wave interval gradually increases or decreases as the temporal position of the half-wave interval becomes later.

[0064] Also, in the above embodiment, a common drive signal was input to the plurality of vibrators 31 included in the ultrasonic probe 30, but the present invention is not limited to this. The drive signal generation unit 12 may, for example, set modulation drive signals with different widths for each half-wave period according to the arrangement positions of the plurality of vibrators 31 included in the ultrasonic probe 30.

[0065] Also, in the ultrasonic diagnostic apparatus 100, one image is generated by a plurality (one or more) of sound lines continuously emitted from each position in the width direction of the ultrasonic emission surface of the ultrasonic probe 30. For example, the drive signal generation unit 12 may generate drive signals based on a plurality of waveforms different according to the positions within the vibrator array for each of the plurality of vibrators 31. Specifically, the drive signal generation unit 12 varies the transmission intensity between the central element and the end element when generating one sound line. More specifically, the drive signal generation unit 12 assigns, for example, a waveform as shown in FIG. 3A to the central element and, for example, a waveform as shown in FIG. 3B to the end element. By doing so, it is possible to obtain a so-called apodization effect that attenuates the energy of the ultrasonic waves radiated from the peripheral elements with respect to the central element.

[0066] Then, the drive signal generation unit 12 may set a modulation drive signal with different widths for each half-wave period for each of the plurality of waveforms in the drive signal for each sound line. The drive signal generation unit 12 may use, as the drive signal corresponding to the central element and the drive signal corresponding to the end element, modulation drive signals with different widths in the first half-wave section and the third half-wave section. In this case, for example, the drive signal generation unit 12 may generate a modulation drive signal such that the variation width of the first half-wave section and the third half-wave section with respect to the second half-wave section increases as the high-frequency components outside the frequency band of the ultrasonic probe 30 increase.

[0067] By doing so, while obtaining an apodization effect, it is possible to reduce the emission of unnecessary radiation of high-frequency components caused by the drive signal including high-frequency components. Note that when one sound line is emitted from the emission surface of the ultrasonic probe 30 as in the pulsed Doppler mode, drive signals based on a plurality of waveforms different depending on the position within the oscillator array are generated for the one sound line. Then, for each of the plurality of waveforms in the drive signal of the one sound line, a modulation drive signal with different widths for each half-wave period is set.

[0068] Also, in the above embodiment, the modulation drive signal is generated by the drive signal generation unit 12, but the driving ability of the transmission unit has not been particularly mentioned. The drive signal generation unit 12 may generate a modulation drive signal based on a driving ability lower than that of the transmission unit, for example. Specifically, when a drive signal having a frequency corresponding to the maximum driving ability of the transmission unit is set, the drive signal generation unit 12 generates a modulation drive signal having a driving ability lower than that frequency.

[0069] For example, when the rise and fall of the pulse of the drive signal transmitted from the transmission unit are steep, the high-frequency components outside the frequency band of the ultrasonic probe 30 may increase. Therefore, by setting the driving ability lower than that of the transmission unit, the rise and fall of the pulse of the drive signal can be made gentle. As a result, the high-frequency components outside the frequency band can be reduced, and the degree of unnecessary radiation can be decreased.

[0070] Also, in the above embodiment, although the display mode of the ultrasonic diagnostic apparatus 100 has not been particularly mentioned, the drive signal generation unit 12 may generate a drive signal in which at least two widths of a plurality of half-wave intervals are made different according to the display mode of the ultrasonic diagnostic apparatus 100.

[0071] Specifically, when the display mode is a narrow-band transmission mode (for example, a pulsed Doppler mode, a color Doppler mode, and a CWD mode), the drive signal generation unit 12 generates a drive signal in which at least two widths of a plurality of half-wave intervals are made different.

[0072] Thereby, since the widths of a plurality of half-wave intervals are modulated in the display mode in which the problem of unnecessary radiation is likely to occur, an appropriate drive signal corresponding to the display mode can be used. Note that when the display mode is not a narrow-band transmission mode (B mode), the drive signal generation unit 12 may generally generate a drive signal used in the display mode.

[0073] Also, the drive signal generation unit 12 may generate a modulation drive signal according to the setting of the ultrasonic diagnostic apparatus 100.

[0074] Examples of the setting of the ultrasonic diagnostic apparatus 100 include setting of a focus point, setting of an aperture, setting of a transmission voltage, setting of a transmission frequency, and the like.

[0075] For example, in the ultrasonic diagnostic apparatus 100, when the aperture in the ultrasonic probe 30 is relatively wide, since the energy output by the apparatus increases, there is a possibility that the high-frequency component increases. Conditions where the aperture is relatively wide include those where the focus point is set at a relatively deep position and the aperture is set relatively wide.

[0076] Also, in the ultrasonic diagnostic apparatus 100, when the transmission voltage is set relatively high or when the transmission frequency is set relatively high, since the energy output by the apparatus increases, there is a possibility that the high-frequency component increases.

[0077] Therefore, when the ultrasonic diagnostic apparatus 100 is set as described above, the drive signal generation unit 12 generates a modulated drive signal. When the ultrasonic diagnostic apparatus 100 is not set as described above, the drive signal generation unit 12 generates a drive signal composed of a plurality of half-waves of the same width instead of the modulated drive signal.

[0078] By doing so, an appropriate drive signal corresponding to the setting of the ultrasonic diagnostic apparatus 100 can be used.

[0079] Also, in the above embodiment, in the modulated drive signal, the widths of the rest intervals are made different to make the widths of the respective half-wave intervals different. However, the present invention is not limited to this. For example, the drive signal generation unit 12 may generate a modulated drive signal such that the widths of the transmission intervals are different from each other in addition to the widths of the rest intervals.

[0080] Furthermore, each of the above embodiments merely shows an example of implementation of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from the gist or main features thereof.

Explanation of Reference Numerals

[0081] 10 Image generation device 11 Waveform determination unit 12 Drive signal generation unit 13 Received signal processing unit 14 Transmission / reception unit 15 Control unit 16 Image processing unit 17 Storage unit 18 Operation input unit 19 Display unit 30 Ultrasonic probe 31 Vibrator 40 Cable 100 Ultrasonic diagnostic apparatus

Claims

1. A drive signal generation unit that generates a drive signal based on a pulse signal for driving an ultrasonic probe, A transmission unit that transmits the drive signal to the ultrasonic probe, Comprising, Each of the plurality of half-wave intervals constituting the pulse signal includes one or more transmission intervals and one or more rest intervals, The drive signal generation unit generates a modulation drive signal, which is the drive signal, with at least two widths of the plurality of half-wave intervals being different so that the widths of the rest intervals are different from each other, An ultrasonic diagnostic apparatus.

2. The drive signal generation unit generates a modulation drive signal composed of a first half-wave interval, a second half-wave interval having a width wider than that of the first half-wave interval, and a third half-wave interval having a width wider than that of the second half-wave interval, The ultrasonic diagnostic apparatus according to claim 1.

3. The width of the second half-wave interval is a width corresponding to the transmission frequency of the ultrasonic probe, The sum of the width of the first half-wave interval, the width of the second half-wave interval, and the width of the third half-wave interval is three times the width of the second half-wave interval, The ultrasonic diagnostic apparatus according to claim 2.

4. The temporal position of the second half-wave interval is between the temporal position of the first half-wave interval and the temporal position of the third half-wave interval, The ultrasonic diagnostic apparatus according to claim 3.

5. The drive signal generation unit generates a modulation drive signal that repeats an interval group including the first half-wave interval, the second half-wave interval, and the third half-wave interval one by one, The ultrasonic diagnostic apparatus according to claim 4.

6. The drive signal generation unit generates a modulation drive signal that repeats each of the first half-wave interval, the second half-wave interval, and the third half-wave interval a plurality of times, The ultrasonic diagnostic apparatus according to claim 4.

7. The drive signal generation unit generates the modulation drive signal such that the plurality of half-wave intervals have a plurality of transmission intervals and a plurality of rest intervals, The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

8. The drive signal generation unit, When generating each of one or more sound lines emitted from the emission surface of the ultrasonic probe, for each of the plurality of vibrators of the ultrasonic probe, a drive signal based on a plurality of waveforms different depending on the position in the vibrator array is generated for each sound line, For each of the plurality of waveforms in the drive signal for each sound line, a modulation drive signal with different widths for each half-wave period is set, The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

9. The drive signal generation unit generates a modulation drive signal based on a drive capability lower than the maximum drive capability of the transmission unit. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

10. When the display mode is narrowband transmission, the drive signal generation unit generates the modulation drive signal. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

11. The drive signal generation unit generates the modulation drive signal according to the setting of the ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

12. The drive signal generation unit generates the modulation drive signal such that the widths of the transmission intervals are different from each other. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6.

13. A drive signal generation method in an ultrasonic diagnostic apparatus, comprising: generating a drive signal based on a pulse signal for driving an ultrasonic probe; transmitting the drive signal to the ultrasonic probe; wherein each of a plurality of half-wave intervals constituting the pulse signal includes one or more transmission intervals and one or more rest intervals; in generating the drive signal, a modulation drive signal is generated as the drive signal by making at least two widths of the plurality of half-wave intervals different from each other so that the widths of the rest intervals are different from each other. Drive signal generation method.

14. A drive signal generation program in an ultrasonic diagnostic apparatus, causing a computer to generate a drive signal based on a pulse signal for driving an ultrasonic probe; transmit the drive signal to the ultrasonic probe; wherein each of a plurality of half-wave intervals constituting the pulse signal includes one or more transmission intervals and one or more rest intervals; the process of generating the drive signal includes a process of generating, as the drive signal, a modulation drive signal in which at least two widths of the plurality of half-wave intervals are different from each other so that the widths of the rest intervals are different from each other. Drive signal generation program. ​

Images