JP2004159770A - Ultrasonic diagnostic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the transmission of ultrasonic waves according to presence/absence of a diagnosis, namely the necessity of the transmission, in ultrasonic diagnostic equipment. <P>SOLUTION: In the figure, (a) is a transmission signal and shows states where a search unit is used and released subsequently in air. (b) is a present receiving signal and (c) shows a receiving signal one line prior to the present. The receiving signal is thus changed for every one line when the search unit is used, while it is scarcely changed in the air release. A difference between the receiving signal (b) and the signal (c) is found and a waveform after the detection is shown in (d). The signal after the difference and the detection becomes an extremely small signal in the air release. The difference signal is treated with a low pass filter and a threshold, outputted to a CPU (central processing unit) and used as a power limit determination and a power limit control. The difference between the receiving signals is processed under the power limit control and a power restoration control is performed based on the difference signal. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that restricts transmission of ultrasonic waves when the apparatus is not used.
[0002]
[Prior art]
The ultrasonic diagnostic apparatus uses a probe having a plurality of vibrating elements inside, supplies a high-voltage transmission drive signal to each vibrating element, and transmits ultrasonic waves to a target living body. Therefore, if the transmission of the ultrasonic wave is continued when the diagnosis is not performed, the probe generates heat and causes deterioration. Therefore, when the operation panel of the ultrasonic diagnostic apparatus is not used for a certain period of time, the transmission is stopped using, for example, a timer.
[0003]
[Problems to be solved by the invention]
However, in the method using the timer, the transmission is uniformly stopped after a predetermined time regardless of the presence or absence of the diagnosis unless the operation panel is used. Therefore, for example, even when the diagnosis is continued in the same mode, the transmission of the ultrasonic wave is stopped and the diagnosis is interrupted. Further, once the transmission is stopped, the operation panel must be operated again to restart the transmission, which is complicated.
[0004]
An object of the present invention is to solve the problems of the related art and to provide an ultrasonic diagnostic apparatus capable of controlling transmission when there is no need to transmit ultrasonic waves. Another object of the present invention is to provide an ultrasonic diagnostic apparatus capable of automatically restarting transmission when transmission of ultrasonic waves is required.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an ultrasonic diagnostic apparatus according to the present invention includes a transmitting and receiving unit that outputs a received signal by transmitting and receiving ultrasonic waves, and a difference operation between two received signals output from the transmitting and receiving unit. A difference means for executing and outputting a difference signal; and detecting a non-change state in which the magnitude of the difference signal is smaller than the first judgment value, and limiting the power in a case where the non-change state continues for a first judgment period or more. The present invention is characterized by comprising: a limit determining unit for determining; and a power limiting unit for executing power limit control on transmission of an ultrasonic wave when the power limit is determined.
[0006]
The waveform of the received signal when the probe is in contact with the living body is not always the same due to changes in the posture of the probe, movement of the living body, and the like. On the other hand, when the contact with the living body or the like is stopped, the ultrasonic wave from the probe is radiated into the air, and the received signal has substantially the same waveform. By utilizing this, with the above-described configuration, a difference signal between the received signals is obtained, and when the difference signal is smaller than the first determination value for more than the first determination period, contact with a living body or the like is performed. Thinking that there is no, you can limit the power. Regarding the power limitation, the transmission of the ultrasonic wave can be stopped, or the transmission can be continued after setting the transmission power level of the ultrasonic wave to a low level. Therefore, transmission can be restricted when there is no need to transmit ultrasonic waves.
[0007]
Further, the ultrasonic diagnostic apparatus according to the present invention includes a transmitting / receiving means for outputting a received signal by transmitting / receiving ultrasonic waves, and two transmitting / receiving means for transmitting / receiving ultrasonic waves under power limitation control. Difference means for performing a difference operation between the received signals to output a difference signal, detecting a change state in which the magnitude of the difference signal exceeds a second determination value, and the change state continues for a second determination period or more. In this case, there is provided a restoration judging means for judging power restoration in the case, and a power restoration means for executing power restoration control for transmission of the ultrasonic wave when the power restoration is judged.
[0008]
According to this configuration, when the state in which the difference signal exceeds the second determination value continues for the second determination period after the power is limited, it is considered that the contact with the living body or the preparation for the living body is being performed, and the power limitation is performed. Power can be restored to the previous state. The contact with or preparation for the living body includes application of a jelly-like acoustic matching agent to the probe. Therefore, when the transmission of the ultrasonic wave is required, the transmission in the power restored state can be automatically restarted.
[0009]
Further, an ultrasonic diagnostic apparatus according to the present invention includes a transmitting / receiving means for outputting a received signal by transmitting / receiving ultrasonic waves, and a differential signal obtained by performing a difference operation between two received signals output from the transmitting / receiving means. A limiting means for determining a power limitation based on a non-change state in which the magnitude of the difference signal is smaller than a first determination value; and transmitting an ultrasonic wave when the power limitation is determined. Power limiting means for performing power limiting control, power recovery control, and restoration determining means for determining power restoration based on a change state in which the magnitude of the difference signal exceeds a second determination value after execution of the power limiting control; Power restoration means for executing power restoration control for transmission of ultrasonic waves when restoration is determined. The power limitation in this case is to limit the transmission power to a limit at which the power restoration can be determined and to continue the transmission.
[0010]
Further, the power limiting means performed prior to the determination of the power restoration, the transmission drive voltage of the ultrasonic wave, the repetition frequency of the transmitted ultrasonic pulse, the number of burst waves of the ultrasonic pulse and the ultrasonic wave It is preferable to perform control for changing at least one of the scanning angles of the ultrasonic beam formed by the transmission and reception.
[0011]
With this configuration, at least one of a reduction in the transmission drive voltage, a reduction in the repetition frequency of the ultrasonic pulse, a reduction in the number of burst waves, and a reduction in the scan angle is performed, and the power consumption is reduced while suppressing the deterioration of the probe. A determination of restoration can be made.
[0012]
Further, in the ultrasonic diagnostic apparatus according to the present invention, it is preferable that a period during which the change state continues in the determination of the power restoration is shorter than a period during which the non-change state continues in the determination of the power limitation. With this configuration, the responsiveness of power restoration can be appropriately improved.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of the ultrasonic diagnostic apparatus 10.
[0014]
The probe 12 includes an array vibrator (not shown) therein, and the array vibrator includes a plurality of vibrating elements.
[0015]
The transmission circuit 14 is a circuit that supplies a transmission signal delayed for each of the plurality of vibrating elements constituting the array vibrator under the control of the transmission control circuit 16, and has a function as a so-called transmission beamformer. The transmission signal supplied to each vibrating element is a high voltage having an amplitude value of about 100 V, for example.
[0016]
The transmission control circuit 16 is a local control circuit that controls the transmission circuit under the control of a CPU 60 described later. The transmission control circuit 16 has a function as a means for performing power limitation and power restoration of a transmission signal, which will be described in detail later.
[0017]
The receiving circuit 18 amplifies the echo signal from the probe 12 by a preamplifier, adjusts the phase difference between the signals of the respective vibrating elements, performs an adding process, and obtains a signal processing unit 20 and a signal difference processing unit 40 as a received signal. And has a function as a so-called reception beamformer.
[0018]
The signal processing unit 20 is a circuit having a function of performing signal processing on an input received signal and outputting the signal to the image processing unit 28. In the signal processing unit 20, the detector 22 is a circuit for extracting and detecting the envelope amplitude of the input received signal, and the bandpass filter 24 is a bandpass filter for removing noise of the signal after the detection, and is a logarithmic conversion. The device 26 is a circuit that performs logarithmic compression processing on the signal after the envelope detection.
[0019]
The image processing unit 28 is a circuit that performs gain adjustment, AGC processing, and the like on the output of the signal processing unit 20, performs processing such as coordinate conversion and data interpolation, and forms a B-mode tomographic image. The image processing unit 28 can be configured by a so-called digital scan converter (DSC) or various image processing circuits. The formed B-mode tomographic image is output to the display 30.
[0020]
The signal difference processing unit 40 includes a subtractor 42, a line memory 44, a detector 46, a low-pass filter 48, and a threshold processing circuit 50. This is a circuit having a function of a difference unit that performs a difference process. The output is output to the CPU 60.
[0021]
The function of each element of the signal difference processing unit 40 will be described below with reference to FIG. FIG. 2 shows time on the horizontal axis and signal amplitude on the vertical axis, and shows the received signal waveform in (b) and the signal difference processing in (c) and below, based on the repeatedly transmitted transmission signal shown in (a). FIG. 4 is a diagram showing each element output waveform of a unit 40. The time axis has a common origin. In the figure, the first Tx1, Tx2, and Tx3 of the transmission signals are used when the probe 12 is in contact with the living tissue, and the transmission signal after Tx4 is used when the probe 12 is out of the living tissue. This is the time when the device is left in the air where the ultrasonic waves are emitted into the air.
[0022]
The subtracter 42 is a circuit that performs a subtraction process between the received signal and the immediately preceding received signal, and outputs a difference signal. Specifically, in response to the repeated transmission of the ultrasonic wave, the received signal repeatedly received from the receiving circuit 18 is processed in data units of one line, and the received signal data of one line and one line of the data are processed. A subtraction process is performed with the previous received signal data. The reception signal for one line is a reception signal for one beam. The line memory 44 is a memory for storing received signal data one line before the data. Note that the subtraction process can be performed between the received signal and any other received signal, and need not necessarily be performed between the signal and the immediately preceding received signal.
[0023]
FIG. 2B shows a reception signal corresponding to the transmission signal of FIG. 2A, that is, a current reception signal output from the reception circuit 18 with respect to the transmission signal, and FIG. That is, the received signal one line before the present received signal is shown. As shown in FIG. 2B, the received signal during use differs from one line to another depending on the posture of the probe or the movement of the living body, whereas the probe 12 is removed from the living tissue. The reception signal when left in the air where the ultrasonic waves are radiated in the air hardly changes.
[0024]
By using this difference, it is possible to distinguish between use and leaving in the air. However, even when the probe is in contact with the living body, the probe is in contact with the living tissue, for example, when the posture of the probe is the same and the movement of the living body is stable, the received signal changes little. Sometimes. Therefore, when the observation of the change in the received signal is continued for a certain period of time, and the change in the received signal hardly changes, it can be considered that it is not in use but in the air.
[0025]
The difference signal is input to the detector 46. The detector 46 is a circuit that detects the input difference signal having the plus and minus amplitudes and converts the difference signal into an absolute value. The signal after detection is output to the low-pass filter 48. Note that the order of the subtraction process and the detection process may be such that the subtraction process is performed on the RF signal as described above, and then the detection process is performed. Good.
[0026]
FIG. 2D shows an output waveform of the detector 46. As shown in the figure, from the time corresponding to the fourth transmission signal, the signal waveform after detection has only a noise component and is extremely small. When this state continues for a certain period of time, it can be considered that it is not in use but in the air.
[0027]
The low-pass filter 48 is a filter that removes high frequency component noise from the detected signal. The signal after noise removal is output to the threshold processing circuit 50. FIG. 2E shows the output of the low-pass filter 48.
[0028]
The threshold value processing circuit 50 is a circuit that performs a threshold value process on the output waveform of the low-pass filter 48 under the control of a CPU 60 to be described later and outputs a rectangular waveform. In FIG. 2E, the threshold 52 is shown by a broken line in relation to the output waveform of the low-pass filter 48. By detecting the threshold value or more, it is determined whether the device is in use or left in the air. FIG. 2F shows the output of the threshold processing circuit 50. In the present embodiment, a case where the level is equal to or lower than the threshold is set to the low level, and the level equal to or higher than the threshold is set to the high level. The signal after the threshold processing is output to CPU 60.
[0029]
The CPU 60 is an arithmetic processing unit having a function of controlling each component of the ultrasonic diagnostic apparatus 10, and includes a limit determining unit 62 and a restoration determining unit 64. The functions of these elements will be described below with reference to the flowchart of FIG.
[0030]
The CPU 60 controls transmission and reception of ultrasonic waves (S10). At the same time, whether or not power should be limited is determined by the limit determination unit 62 based on the output of the threshold processing circuit 50 (S12). If it is determined that the power should be limited, the process proceeds to the next step. If it is determined that the power should not be limited, the output of the threshold processing circuit 50 is continuously monitored.
[0031]
Specifically, a threshold value used for the power limit determination is given to the threshold value processing circuit 50, and the presence or absence of a rectangular waveform subjected to the threshold value process under the threshold value for the power limit determination is determined. It can be determined that the power should be limited when the rectangular waveform is detected and the rectangular waveform is not detected for a predetermined time or more. The threshold value and the predetermined time used for the power limitation determination are set according to the level of the power limitation determination. For example, the predetermined time can be set to 5 minutes using a timer.
[0032]
When it is determined that the power should be limited, the power control is performed on the transmission control circuit 16 (S14). More specifically, the transmission control circuit 16 is controlled so that the power is reduced from the initial transmission condition and the transmission is continued. The contents of the power down include, for example, the transmission drive voltage of the ultrasonic wave, the repetition frequency of the transmitted ultrasonic pulse, the burst wave number of the ultrasonic pulse, and the scan angle of the ultrasonic beam formed by the transmission and reception of the ultrasonic wave. At least one of them can be changed. For example, the transmission driving voltage can be reduced to 10%, the repetition frequency of the ultrasonic pulse can be reduced to 10 Hz, the burst wave can be made a single pulse, and the ultrasonic beam can be fixed in the central direction to continue the transmission.
[0033]
Under the power limitation control, the restoration determining unit 64 determines whether or not to restore the power based on the output of the threshold processing circuit 50 (S16). If it is determined that the power should be restored, the transmission control circuit 16 is controlled to return the transmission to the original transmission condition before the power limitation (S10). The output of the threshold value processing circuit 50 is monitored.
[0034]
Specifically, a threshold value used for power restoration determination is given to the threshold processing circuit 50, and the presence or absence of a rectangular waveform subjected to threshold processing under the power restoration determination threshold value is determined. It can be determined that the power should be limited when the rectangular waveform is detected for a predetermined time or more. The duty of the rectangular waveform may be used as data for determining power restoration.
[0035]
The threshold value and the predetermined time used for the power restoration determination are set according to the level of the power restoration determination. As these values, values different from those used for power limitation may be used. For example, it can be determined that power should be restored when a rectangular signal is detected ten times in a row. In this case, if the repetition frequency of the ultrasonic pulse is set to 10 Hz, the transmission condition before the power limitation can be restored in about 1 second, and the responsiveness of the power restoration is good. Further, the threshold value used for the power restoration determination can be set, for example, to a level at which a rectangular waveform can be detected in a state where the jelly-like acoustic matching agent for diagnosis is applied to the probe.
[0036]
In this manner, based on the difference between the current received signal data and the immediately preceding received signal data, the determination as to whether power should be limited and the determination as to whether power should be restored can be made in a relatively short time. It can be carried out. For example, the determination as to whether or not to limit the power can be made as short as about 5 minutes, for example, about 20 minutes in the related art, and the determination as to whether or not to restore the power can be made in 1 second, for example.
[0037]
In the above description, the input to the signal difference processing unit 40 is the output of the receiving circuit 18, that is, the RF signal, but the output signal of each component of the signal processing unit 20 or the output signal of each component of the image processing unit 28. The present invention can be implemented using an output signal. For example, the signal difference processing may be performed from the output of the detector 22, the output of the band-pass filter 24, the output of the logarithmic converter 26, the output of the image processing unit 28 after the gain adjustment, the output after the AGC processing, and the like.
[0038]
In the above description, the signal difference processing is performed on the data of one line as a unit. However, the present invention can be implemented by performing the signal difference processing on a part of the data of one line. For example, signal difference processing may be performed between data in the same diagnostic depth range.
[0039]
Also, the ultrasonic diagnostic apparatus shown in FIG. 1 has been described as having the B mode, and the received signal to be subjected to the signal difference processing is used for the B mode signal processing or the like. The present invention can be applied to a Doppler mode or the like.
[0040]
【The invention's effect】
According to the ultrasonic diagnostic apparatus of the present invention, transmission can be controlled when transmission of ultrasonic waves is not necessary. ADVANTAGE OF THE INVENTION According to the ultrasonic diagnostic apparatus which concerns on this invention, when transmission of an ultrasonic wave is needed, transmission restart can be performed automatically.
[Brief description of the drawings]
FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a state of a signal waveform in each process of signal difference processing.
FIG. 3 is a flowchart of transmission control related to power limitation and power restoration.
[Explanation of symbols]
Reference Signs List 10 ultrasonic diagnostic apparatus, 12 probe, 14 transmission circuit, 16 transmission control circuit (power limiting means, power restoration means), 18 reception circuit, 40 signal difference processing section (difference means), 42 subtractor, 44 line memory , 46 detector, 48 low-pass filter, 50 threshold processing circuit, 60 CPU, 62 limit determining unit, 64 restoration determining unit.

Claims (5)

Transmitting and receiving means for outputting a received signal by transmitting and receiving ultrasonic waves,
Difference means for executing a difference operation between two received signals output from the wave transmitting / receiving means and outputting a difference signal;
Limit determination means for detecting a non-change state in which the magnitude of the difference signal is less than a first determination value, and determining a power limit when the non-change state continues for a first determination period or more;
Power limiting means for performing power limiting control for transmission of ultrasound when the power limitation is determined,
An ultrasonic diagnostic apparatus comprising: Transmitting and receiving means for outputting a received signal by transmitting and receiving ultrasonic waves,
Difference means for executing a difference operation between two received signals output from the wave transmitting and receiving means by transmitting and receiving ultrasonic waves under power limiting control to output a difference signal;
Restoration determination means for detecting a change state in which the magnitude of the difference signal exceeds a second determination value, and for determining power recovery when the change state continues for a second determination period or more;
Power restoration means for executing power restoration control for transmission of ultrasound when the power restoration is determined,
An ultrasonic diagnostic apparatus comprising: Transmitting and receiving means for outputting a received signal by transmitting and receiving ultrasonic waves,
Difference means for executing a difference operation between two received signals output from the wave transmitting / receiving means and outputting a difference signal;
Limit determination means for determining power limitation based on a non-change state in which the magnitude of the difference signal is less than a first determination value;
Power limiting means for performing power limiting control for transmission of ultrasound when the power limitation is determined,
Restoring determination means for determining power restoration based on a change state in which the magnitude of the difference signal exceeds a second determination value after execution of the power limit control;
Power restoration means for executing power restoration control for transmission of ultrasound when the power restoration is determined,
An ultrasonic diagnostic apparatus comprising: The ultrasonic diagnostic apparatus according to any one of claims 1 to 3,
The power limiting unit includes a transmission drive voltage of the ultrasonic wave, a repetition frequency of the transmitted ultrasonic pulse, a burst wave number of the ultrasonic pulse, and a scan angle of an ultrasonic beam formed by transmission and reception of the ultrasonic wave. An ultrasonic diagnostic apparatus that performs control to change at least one of the ultrasonic diagnostic apparatuses. The ultrasonic diagnostic apparatus according to claim 3,
An ultrasonic diagnostic apparatus, wherein a period in which the change state continues in the determination of the power restoration is shorter than a period in which the non-change state continues in the determination of the power limitation.

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