JP2025110771A - Ultrasound diagnostic device, drive signal generation method, and drive signal generation program - Google Patents

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

The present invention relates to an ultrasound diagnostic device, a drive signal generation method, and a drive signal generation program.

Conventionally, ultrasound diagnostic devices have become widespread, capable of examining the interior of a subject by transmitting ultrasound waves toward the subject using an ultrasound probe and receiving reflected waves from the subject.

In an ultrasound diagnostic device, ultrasonic waves are generated by inputting a drive signal based on a pulse signal. For example, Patent Document 1 discloses a device that can vary the duty ratio of the drive signal for an ultrasound probe (ultrasound generating means).

WO 2004/110278

However, if the drive signal contains frequency components (high-frequency components) higher than the frequency band of the ultrasound probe, 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 values, it becomes necessary to limit the drive voltage to the device. Limiting the drive voltage to the device may lead to degradation of ultrasound-based diagnostic images.

The object of the present invention is to provide an ultrasound diagnostic device, a drive signal generation method, and a drive signal generation program that can suppress degradation of diagnostic images due to unwanted radiation.

The ultrasonic diagnostic apparatus according to the present invention comprises:
a drive signal generating unit that generates a drive signal based on a pulse signal for driving the ultrasonic probe;
a transmitter that transmits the drive signal to the ultrasonic probe;
Equipped with
each of the plurality of half-wave sections constituting the pulse signal includes one or more transmission sections and one or more pause sections;
The drive signal generating section generates, 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.

A drive signal generating method according to the present invention includes:
A method for generating a driving signal in an ultrasound diagnostic apparatus, comprising:
generating a drive signal based on the pulse signal for driving the ultrasonic probe;
transmitting the drive signal to the ultrasound probe;
and
each of the plurality of half-wave sections constituting the pulse signal includes one or more transmission sections and one or more pause sections;
In generating the drive signal, a modulated drive signal is generated as the 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.

A drive signal generation program according to the present invention includes:
A drive signal generation program for an ultrasound diagnostic apparatus,
On the computer,
A process of generating a drive signal based on a pulse signal for driving an ultrasonic probe;
transmitting the drive signal to the ultrasound probe;
Execute
each of the plurality of half-wave sections constituting the pulse signal includes one or more transmission sections and one or more pause sections;
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.

This invention makes it possible to suppress degradation of diagnostic images due to unwanted radiation.

1 is a diagram showing a schematic configuration of an ultrasound diagnostic apparatus according to an embodiment of the present invention; 1 is a block diagram showing the main functional configuration of an ultrasound diagnostic apparatus. FIG. 4 is a diagram illustrating an example of a modulated drive signal. FIG. 4 is a diagram illustrating an example of a modulated drive signal. FIG. 10 is a diagram showing experimental results in a comparative example. FIG. 1 is a diagram showing experimental results in an example. FIG. 10 is a diagram illustrating an example of a modulated drive signal according to a modified example. FIG. 10 is a diagram illustrating an example of a modulated drive signal according to a modified example. FIG. 10 is a diagram illustrating an example of a modulated drive signal according to a modified example.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing the general 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.

As shown in FIG. 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.

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

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.

The waveform determination unit 11 determines the waveform of the drive signal (pulse signal) for driving the ultrasound probe 30. The waveform determination unit 11 determines a drive waveform that matches the transmission characteristics of the ultrasound probe 30. The waveform determination unit 11 determines a drive waveform corresponding to a display mode using waveform information pre-stored in the waveform information storage unit 111. The waveform information storage unit 111 stores waveform information that pre-associates candidate transmission voltages for each display mode with transmission waveforms corresponding to those transmission voltages.

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, for example, in the memory unit 17, or are input by an operator via the operation input unit 18. The transmission conditions include, for example, the transmission aperture, focal position, transmission interval, and transmission voltage. Details of the drive signal generated by the drive signal generation unit 12 will be described later.

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 generates a clock signal that determines the transmission timing and transmission frequency of the pulse signal. The pulse generation circuit generates a rectangular wave pulse of a transmission voltage based on the 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 transducer 31 of the ultrasound probe 30 before or after input to the pulse width setting unit. The delay circuit delays the generated rectangular wave pulse by a delay time set for each of these wiring paths, depending on the timing of transmission to each transducer 31, and outputs it.

The pulse generating circuit has multiple wave numbers and can generate rectangular wave pulses with three values (+V, 0, -V) or five values (+V1, +V2, 0, -V2, -V1).

It is also desirable that the pulse generating circuit be capable of arbitrarily changing at least one of the rise time and fall time of the pulses it generates.It is also desirable that the pulse generating circuit be capable of arbitrarily changing at least one of the rise time and fall time in accordance with the display mode.

This will be explained using a specific example. When the display mode is B-mode, it is preferable to make the rise and fall times relatively short and to control them precisely. On the other hand, when the display mode is pulse Doppler mode, color Doppler mode, or CWD (continuous wave doppler) mode, unlike B-mode, a limited range of low frequencies is used. In this case, because frequency components in the high-frequency range can cause unnecessary heat generation and violate electromagnetic wave regulations, it is preferable to make the rise and fall times relatively long to suppress the generation of harmonics.

The received signal processing unit 13 is a circuit that acquires received signals input from the ultrasonic probe 30 under the control of the control unit 15. The received signal processing unit 13 includes, for example, an amplifier, an A/D conversion circuit, and a phasing and summing circuit. The amplifier amplifies received signals corresponding to ultrasonic waves received by each transducer 31 of the ultrasonic probe 30 at a predetermined amplification factor. The A/D conversion circuit converts the amplified received signals into digital data at a predetermined sampling frequency. The phasing and summing circuit adjusts the time phase of the A/D converted received signals by applying a delay time to each wiring path corresponding to each transducer 31, and then adds these signals (phasing and summing) to generate sound ray data.

When the transmitter/receiver 14 causes the transducer 31 to emit ultrasound waves under the control of the controller 15, it transmits the drive signal generated by the drive signal generator 12 to the transducer 31 (ultrasound probe 30). When the transmitter/receiver 14 acquires a signal related to the ultrasound waves emitted by the transducer 31, it outputs a received signal to the received signal processor 13. The transmitter/receiver 14 corresponds to the "transmitter" of the present invention.

The control unit 15 includes a CPU 151 (Central Processing Unit), a HDD 152 (Hard Disk Drive), and a RAM 153 (Random Access Memory). The CPU 151 reads various programs stored in the HDD 152, loads them into the RAM 153, and controls the operation of each component of the ultrasound diagnostic device 100 in accordance with the loaded programs. The HDD 152 stores control programs and various processing programs that operate the ultrasound diagnostic device 100, various setting data, image files generated by the ultrasound diagnostic device 100, and the like. These programs and setting data may be stored in the HDD 152 or in an auxiliary storage device using nonvolatile memory such as flash memory in a readable, writable, and updatable manner. The RAM 153 is a volatile memory such as an SRAM or DRAM, and provides working memory space for the CPU 151 and stores temporary data. The ultrasound diagnostic device 100 with the control unit 15 can be considered a type of computer.

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

The storage unit 17 is, for example, a volatile memory such as a dynamic random access memory (DRAM). Alternatively, it may be any type of non-volatile memory that can be rewritten at high speed. The storage unit 17 stores various data, programs, and the like required for the operation of the ultrasound diagnostic device 100.

The storage unit 17 also stores, in frame units, image data of ultrasound images for real-time display that have been processed by the image processing unit 16. The image data stored in the storage unit 17 is read out under the control of the control unit 15, and is sent to the display unit 19 or output to the outside of the ultrasound diagnostic device 100 via a communication unit (not shown). In this case, if the display system of the display unit 19 is a television system, a DSC (Digital Signal Converter: not shown) can be provided between the storage unit 17 and the display unit 19, and the image can be output after the scan format has been converted.

The operation input unit 18 includes a push button switch, keyboard, mouse, touchpad, or trackball, or a combination of these, and converts input operations by the operator into operation signals and outputs them to the control unit 15. The touchpad serving as the operation input unit 18 may be overlaid on the display unit 19 to form a touch panel.

The display unit 19 has a predetermined display screen and its driver. 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. The display unit 19 generates drive signals for the display screen (each display pixel) in accordance with control signals output from the CPU 151 and image data generated by the image processing unit 16. The display unit 19 then displays on the display screen menus and status related to ultrasound diagnosis, as well as measurement data such as ultrasound images based on received ultrasound.

The operation input unit 18 and display unit 19 may be integrated into the housing of the image generation device 10, or may be attached externally via a USB cable or the like. Furthermore, if the image generation device 10 is provided with operation input terminals and display output terminals, these terminals may be used by connecting conventional operation and display peripheral devices.

The ultrasound probe 30 oscillates and transmits (emits) ultrasound waves (for example, approximately 1 to 30 MHz) to a subject such as a living organism. The ultrasound probe 30 also functions as an acoustic sensor that receives reflected waves (echoes) from the subject and converts them into electrical signals. This ultrasound probe 30 is equipped with a transducer array 310, which is an array of multiple transducers 31 that transmit and receive ultrasound waves.

The transducer array 310 is an array of multiple transducers 31 each equipped with a piezoelectric element having a piezoelectric body and electrodes at both ends of the piezoelectric body where a charge appears due to deformation (expansion and contraction) of the piezoelectric body. When a voltage pulse (drive signal) is supplied to the transducers 31, the piezoelectric body deforms in response to the electric field generated in each piezoelectric body, and ultrasonic waves are emitted. Furthermore, when ultrasonic waves of a predetermined frequency band are incident on the transducers 31, the sound pressure causes the thickness of the piezoelectric body to fluctuate (vibrate), and electric charges corresponding to the amount of fluctuation appear at both ends of the piezoelectric body in the thickness fluctuation direction, and an amount of charge corresponding to the electric charge is induced in the electrodes at both ends of the piezoelectric element.

The transducer array 310 of the ultrasound probe 30 includes, for example, around one hundred to several hundred transducers 31 arranged one-dimensionally in a predetermined transducer array direction. Alternatively, the transducers 31 may be arranged two-dimensionally in a direction perpendicular to the transducer array direction. Furthermore, the number of transducers 31 may be set arbitrarily.

The ultrasonic probe 30 transmits ultrasonic waves from a set of consecutive transducers 31 based on a drive signal from the drive signal generator 12. Each time an ultrasonic wave is generated, the set of transducers 31 transmitting the ultrasonic waves is shifted in the transducer array direction by a predetermined number of transducers 31, thereby performing a scan in a scanning direction SD (see Figure 2) parallel to the transducer array direction. The ultrasonic probe 30 may employ any of a variety of scanning methods. Scanning methods include various electronic scanning methods such as linear electronic scanning, sector electronic scanning, and convex electronic scanning, as well as linear scanning, sector scanning, arc scanning, and radial scanning.

Furthermore, this ultrasound diagnostic device 100 may be configured so that one of multiple different ultrasound probes 30 can be connected to the image generating device 10 and used depending on the diagnostic subject.

The cable 40 has a connector (not shown) at one end for connection to the image generating device 10, and the ultrasound probe 30 is configured to be attachable and detachable to the image generating device 10 via this cable 40.

Next, we will explain in detail the drive signal generated by the drive signal generation unit 12.

In this embodiment, the drive signal generation unit 12 generates a modulated drive signal (see, for example, Figure 3A) in which each of the multiple half-wave sections that make up the pulse signal for driving the ultrasound probe 30 includes one or more transmission sections and one or more pause sections.

A half-wave section is a section of half the wavelength of a pulse signal. A transmission section is a section that is the high period of a pulse signal (including the high period on the positive side and the high period on the negative side). A pause section is a section that is the low period of a pulse signal.

By setting such pause intervals, it is possible to adjust the intensity level of the ultrasound waves without changing the cycle of the drive signal. For example, the lower the intensity level of the ultrasound waves is set, the longer each pause interval is set.

Figure 3A shows an example in which a half-wave section has one transmission section and one pause section. Figure 3B shows an example in which a half-wave section has two transmission sections and two pause sections.

Specifically, the drive signal generation unit 12 generates a drive signal having multiple half-wave sections, each consisting of a first half-wave section, a second half-wave section, and a third half-wave section, each with a different width. The widths of the pause sections in the first half-wave section, the second half-wave section, and the third half-wave section are different from each other. In other words, the drive signal generation unit 12 generates a drive signal in which the widths of at least two of the multiple half-wave sections are different from each other, so that the widths of at least the pause sections are different from each other.

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 the frequency for which transmission is set in the ultrasound diagnostic device 100. The widths of the first half-wave section, the second half-wave section, and the third half-wave section each correspond to a frequency within the frequency band of the ultrasound probe 30.

In Figures 3A and 3B, each of the first two half-wave sections is the first half-wave section. Each of the next two half-wave sections is the second half-wave section. Each of the last two half-wave sections is the third half-wave section. In other words, the time position of the second half-wave section is between the time position of the first half-wave section and the time position of the third half-wave section.

However, depending on the combination of the width of the pause section and the width of the transmission section, the drive signal may contain frequency components (high-frequency components) higher than the frequency band of the ultrasound probe 30. When high-frequency components are included in the drive signal, 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 value, it becomes necessary to limit the drive voltage to the device. Limiting the drive voltage to the device may lead to degradation of ultrasound-based diagnostic images.

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 signal intensity level of each frequency outside the frequency band of the ultrasound probe 30. As a result, it is possible to weaken the signal intensity outside the frequency band compared to the same half-wave interval.

Furthermore, by making the pause period of the third half-wave period longer than the pause period of the second half-wave period, the signal intensity level of each frequency outside the frequency band of the ultrasound probe 30 similarly shifts. As a result, it is possible to weaken the signal intensity outside the frequency band compared to the same half-wave period.

This makes it possible to reduce the overall signal strength level in the range exceeding the frequency band of the ultrasound probe 30. As a result, it is possible to reduce the emission of unnecessary high-frequency radiation caused by the inclusion of high-frequency components in the drive signal, thereby suppressing degradation of diagnostic images.

Furthermore, the total period of the drive signal, including the first, second, and third half-wave sections, is the same as the period when all of the multiple half-wave sections are second half-wave sections. In other words, the sum of the width of the first, second, and third half-wave sections is three times the width of the second half-wave section.

By doing this, the overall frequency corresponding to the modulated drive signal can be adjusted to the frequency corresponding to the second half-wave section. As a result, the ultrasonic waves transmitted from the ultrasonic probe 30 can be made as desired.

In addition, the change range of the first and third half-wave sections of the modulated drive signal relative to the second half-wave section (transmission frequency section) is set, for example, to a predetermined value or more times the transmission frequency. The predetermined value can be set to an appropriate value, such as 20, based on experiments or simulations.

In addition, the waveform information of the modulated drive signal may be stored in advance in the waveform information storage unit 111. In addition, if 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 generate a new modulated drive signal based on the waveform information stored in the waveform information storage unit 111.

Next, a verification experiment using the ultrasound diagnostic device 100 according to this embodiment will be described. In this example, each half-wave section of 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 (e.g., 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.

In addition, in the comparative example, the drive signal is set so that all half-wave sections correspond to the width of the second half-wave section in the example. Furthermore, in the comparative example, the experimental conditions for the ultrasound diagnostic device 100 may be set to any conditions that result in a relatively high signal intensity level outside the frequency band of the ultrasound probe 30, for example, as shown in Figure 4.

Figure 5 shows the experimental results for the example. As shown in Figure 5, in the example, compared to the comparative example, it can be seen that the signal strength levels outside the frequency band are all lower near the frequencies where multiple peak points P1 to P12 are found in the comparative example. In other words, it can be seen that in this embodiment, the signal strength levels in the range beyond the frequency band of the ultrasound probe 30 are reduced overall.

In this embodiment configured as described above, the drive signal generation unit 12 generates a modulated drive signal in which the widths of at least two of the multiple half-wave sections are different so that the widths of the pause sections are different from each other. Specifically, the drive signal generation unit 12 generates a modulated drive signal consisting of a first half-wave section, a second half-wave section having a width wider than that of the first half-wave section, and a third half-wave section having a width wider than that of the second half-wave section.

By doing this, the high-frequency components of each half-wave section can be shifted, making it possible to reduce the overall signal strength level in the range beyond the frequency band of the ultrasound probe 30. As a result, it is possible to reduce the emission of unnecessary high-frequency radiation caused by the inclusion of high-frequency components in the drive signal, thereby suppressing degradation of diagnostic images.

Furthermore, the width of the second half-wave section corresponds to the transmission frequency of the ultrasonic probe 30, and the sum of the widths of the first, second, and third half-wave sections is three times the width of the second half-wave section.

This allows the overall frequency corresponding to the drive signal to be adjusted to the frequency corresponding to the second half-wave section. As a result, the ultrasonic waves transmitted from the ultrasonic probe 30 can be adjusted as desired.

In the above embodiment, the time position of the second half-wave section is after the time position of the first half-wave section and before the time position of the third half-wave section, but the present invention is not limited to this. For example, as shown in FIG. 6, the time position of the second half-wave section may be after the time position of the third half-wave section and before the time position of the first half-wave section.

In addition, in the above embodiment, the drive signal generation unit 12 generates a drive signal that repeats each of the first half-wave section, the second half-wave section, and the third half-wave section twice, but 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 section, the second half-wave section, and the third half-wave section three times. However, it is preferable that the number of times the same half-wave section is repeated be set to an arbitrary number (for example, four times) or less, taking into consideration the number of half-wave sections in the entire drive signal, etc.

In addition, in the above embodiment, the drive signal generation unit 12 generates a drive signal that repeats each half-wave section multiple 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 sections that includes one first half-wave section, one second half-wave section, and one third half-wave section.

Furthermore, in the above embodiment, the modulated drive signal is composed of three half-wave sections, but the present invention is not limited to this. For example, the modulated drive signal may include three or more half-wave sections. In this case, the modulated drive signal may be a drive signal in which the width of the half-wave sections varies, so that the width of the half-wave sections gradually increases or decreases as the time position of the half-wave sections becomes later.

Furthermore, in the above embodiment, a common drive signal is input to the multiple transducers 31 included in the ultrasound probe 30, but the present invention is not limited to this. For example, the drive signal generation unit 12 may set a modulated drive signal in which the width of each half-wave period differs depending on the arrangement positions of the multiple transducers 31 included in the ultrasound probe 30.

In addition, in the ultrasound diagnostic device 100, a single image is generated from multiple (one or more) sound rays continuously emitted from each position in the width direction of the ultrasound emission surface of the ultrasound probe 30. For example, the drive signal generation unit 12 may generate, for each sound ray, a drive signal based on multiple waveforms that vary depending on the position in the transducer array for each of the multiple transducers 31. Specifically, the drive signal generation unit 12 varies the transmission intensity between the center element and the edge elements when generating one sound ray. More specifically, the drive signal generation unit 12 assigns, for example, a waveform such as that shown in FIG. 3A to the center element, and assigns, for example, a waveform such as that shown in FIG. 3B to the edge elements. This achieves the so-called apodization effect, which attenuates the energy of ultrasound emitted by peripheral elements relative to the center element.

The drive signal generation unit 12 may then set modulated drive signals with different widths for each half-wave period for each of the multiple waveforms in the drive signal for each sound ray. The drive signal generation unit 12 may set the drive signal corresponding to the center element and the drive signal corresponding to the end element as modulated drive signals with different widths for the first and third half-wave sections. In this case, the drive signal generation unit 12 may generate modulated drive signals such that, for example, the greater the amount of high-frequency components outside the frequency band of the ultrasound probe 30, the greater the fluctuation width of the first and third half-wave sections relative to the second half-wave section.

By doing this, it is possible to obtain an apodization effect while reducing the emission of unwanted high-frequency radiation caused by the inclusion of high-frequency components in the drive signal. When a single sound ray is emitted from the emission surface of the ultrasound probe 30, as in pulse Doppler mode, drive signals based on multiple waveforms that differ depending on the position within the transducer array are generated for that single sound ray. Then, modulated drive signals with different half-wave period widths are set for each of the multiple waveforms in the drive signal for that single sound ray.

Furthermore, in the above embodiment, the modulated drive signal was generated by the drive signal generation unit 12, but no specific mention was made of the drive capacity of the transmitter. For example, the drive signal generation unit 12 may generate a modulated drive signal based on a drive capacity lower than the drive capacity of the transmitter. Specifically, when a drive signal with a frequency corresponding to the maximum drive capacity of the transmitter is set, the drive signal generation unit 12 generates a modulated drive signal with a drive capacity lower than that frequency.

For example, if the pulse of the drive signal transmitted from the transmitter has a steep rise and fall, there is a possibility that high-frequency components outside the frequency band of the ultrasonic probe 30 will increase. Therefore, by setting the drive capacity lower than the drive capacity of the transmitter, it is possible to make the rise and fall of the pulse of the drive signal smoother. This reduces the high-frequency components outside the frequency band, thereby reducing the level of unwanted radiation.

Furthermore, although the above embodiment does not specifically mention the display mode of the ultrasound diagnostic device 100, the drive signal generation unit 12 may generate a drive signal in which the widths of at least two of the multiple half-wave sections are different depending on the display mode of the ultrasound diagnostic device 100.

Specifically, when a display mode using narrowband transmission (e.g., pulsed Doppler mode, color Doppler mode, or CWD mode) is selected, the drive signal generation unit 12 generates a drive signal in which at least two of the multiple half-wave sections have different widths.

This modulates the width of multiple half-wave sections in display modes where unwanted radiation problems are likely to occur, allowing the appropriate drive signal to be used according to the display mode. Note that in display modes that do not use narrowband transmission (B mode), the drive signal generation unit 12 may generally generate a drive signal that is used in that display mode.

In addition, the drive signal generation unit 12 may generate a modulated drive signal according to the settings of the ultrasound diagnostic device 100.

Examples of settings for the ultrasound diagnostic device 100 include setting the focus point, aperture, transmission voltage, and transmission frequency.

For example, in the ultrasound diagnostic device 100, if the ultrasound probe 30 has a relatively wide aperture, the energy output by the device increases, which may result in an increase in high-frequency components. Conditions for a relatively wide aperture include when the focus point is set at a relatively deep position, when the aperture is set relatively wide, etc.

Furthermore, when the transmission voltage of the ultrasound diagnostic device 100 is set relatively high, or when the transmission frequency is set relatively high, the energy output by the device increases, which may result in an increase in high-frequency components.

Therefore, when the ultrasound diagnostic device 100 is configured as described above, the drive signal generation unit 12 generates a modulated drive signal, and when the ultrasound diagnostic device 100 is not configured as described above, it generates a drive signal consisting of multiple half-waves of the same width, rather than a modulated drive signal.

By doing this, an appropriate drive signal can be used according to the settings of the ultrasound diagnostic device 100.

Furthermore, in the above embodiment, the width of each half-wave section is made different by varying the width of the pause section in the modulated drive signal, but the present invention is not limited to this. For example, the drive signal generation unit 12 may generate a modulated drive signal so that in addition to the width of the pause section, the width of the transmission section is also different from one another.

Furthermore, the above-described embodiments are merely examples of specific embodiments of the present invention, and the technical scope of the present invention should not be interpreted as being limited by them. In other words, the present invention can be embodied in various forms without departing from its gist or main features.

REFERENCE SIGNS LIST 10 Image generating device 11 Waveform determining unit 12 Drive signal generating unit 13 Received signal processing unit 14 Transmitting/receiving unit 15 Control unit 16 Image processing unit 17 Storage unit 18 Operation input unit 19 Display unit 30 Ultrasonic probe 31 Transducer 40 Cable 100 Ultrasonic diagnostic device

Claims (14)

a drive signal generating unit that generates a drive signal based on a pulse signal for driving the ultrasonic probe;
a transmitter that transmits the drive signal to the ultrasonic probe;
Equipped with
each of the 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 at least two widths 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;
Ultrasound diagnostic equipment. the drive signal generator generates a modulated drive signal including a first half-wave section, a second half-wave section having a width wider than that of the first half-wave section, and a third half-wave section having a width wider than that of the second half-wave section.
The ultrasonic diagnostic apparatus according to claim 1 . the width of the second half-wave section corresponds to the transmission frequency of the ultrasonic probe,
the sum of 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 is three times the width of the second half-wave section;
The ultrasonic diagnostic apparatus according to claim 2 . a time position of the second half-wave section is between a time position of the first half-wave section and a time position of the third half-wave section;
The ultrasonic diagnostic apparatus according to claim 3 . the drive signal generation unit generates a modulated drive signal that repeats a group of sections each including one of the first half-wave section, the second half-wave section, and the third half-wave section.
The ultrasonic diagnostic apparatus according to claim 4. the drive signal generation unit generates a modulated drive signal that repeats each of the first half-wave section, the second half-wave section, and the third half-wave section a plurality of times.
The ultrasonic diagnostic apparatus according to claim 4. the drive signal generation unit generates the modulated drive signal so that the plurality of half-wave sections have a plurality of transmission sections and a plurality of pause sections.
The ultrasonic diagnostic apparatus according to any one of claims 1 to 6. The drive signal generation unit
When generating one or more sound rays emitted from the emission surface of the ultrasonic probe, a drive signal based on a plurality of waveforms that differ depending on a position in an array of transducers is generated for each sound ray for each of the plurality of transducers included in the ultrasonic probe;
A modulated drive signal having a different width for each half-wave period is set for each of the plurality of waveforms in the drive signal for each acoustic ray.
The ultrasonic diagnostic apparatus according to any one of claims 1 to 6. the drive signal generation unit generates a modulated 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. the drive signal generation unit generates the modulated drive signal when the display mode is a narrowband transmission mode.
The ultrasonic diagnostic apparatus according to any one of claims 1 to 6. the drive signal generation unit generates the modulated drive signal in accordance with settings of the ultrasonic diagnostic apparatus.
The ultrasonic diagnostic apparatus according to any one of claims 1 to 6. the drive signal generation unit generates the modulated drive signals so that the widths of the transmission sections are different from each other.
The ultrasonic diagnostic apparatus according to any one of claims 1 to 6. A method for generating a driving signal in an ultrasound diagnostic apparatus, comprising:
generating a drive signal based on the pulse signal for driving the ultrasonic probe;
transmitting the drive signal to the ultrasound probe;
and
each of the plurality of half-wave sections constituting the pulse signal includes one or more transmission sections and one or more pause sections;
In generating the drive signal, a modulated drive signal is generated as the drive signal, in which at least two widths of the plurality of half-wave sections are made different so that the widths of the pause sections are different from each other.
A method for generating a driving signal. A drive signal generation program for an ultrasound diagnostic apparatus,
On the computer,
A process of generating a drive signal based on a pulse signal for driving an ultrasonic probe;
transmitting the drive signal to the ultrasound probe;
Execute
each of the plurality of half-wave sections constituting the pulse signal includes one or more transmission sections and one or more pause sections;
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 widths 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.
Drive signal generation program.