JPH03231645A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To obtain a uniform ultrasonic image without uneven brightness with a correction of sensitivity of each ultrasonic raster to be constant by measuring an intensity of a received echo signal for each ultrasonic raster to control an amplification factor of the received echo signal according to the results of the measurement. CONSTITUTION:An echo signal C received with a probe 4 from an object to be inspected is an echo signal within an acoustic lens 19 and it is obtained as each ultrasonic raster is generated. An intensity of the signal is measured by sampling it at a timing of a sampling pulse D for AGC with an AGC controller 1. An AGC voltage F corresponding to the results of the measurement is outputted. The voltage F is added to an STC voltage G with an adder 2 and applied to an amplifier 14 as AGC-STC voltage H. The amplifier 14 is so controlled that an amplification factor of the echo signal reduced for each ultrasonic raster to be outputted from a long amplifier 13 according to a level of the voltage H when the voltage H is large and it increases when the voltage H is small. The output echo signal of the amplifier 14 is applied to a monitor 17 through a detector 15 and a DSC 16 to be displayed as ultrasonic image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic diagnostic apparatus having an electronic scanning probe that generates an ultrasonic raster through an acoustic lens.

(Prior Art) As a conventional ultrasonic diagnostic apparatus, there is known a configuration as shown in FIG. 5, which uses an electronic scan probe 4 used for linear and convex scanning, for example, as shown in FIG. There is. The electronic scan probe 4 includes a plurality of ultrasonic transducers 4a.

4b, 4c, . . . are arranged in an array, the front surface of which is covered by an acoustic lens 19, and the back surface of which is supported by an alignment material 20. Also, the whole case is case 2
1 and connected to a drive source via a cable 22. In such a probe 4, arbitrary transducers are combined and each set is driven to generate an ultrasonic raster through each acoustic lens.

In FIG. 5, 6 is a pulser that generates N-channel driving pulses for driving each set of multiple (M-channel) transducers of the probe 4, and 5 is a pulser that applies the driving pulse to the M-channel probe 4. Alternatively, it is a changeover switch that operates to apply the echo signal of the subject received by the probe 4 to the N-channel preamplifier 7. The relationship between N and M is often the same, and the probe 4 generates an ultrasonic raster through the acoustic lens 19 every time an N-channel driving pulse is applied. The preamplifier 7 amplifies the weak echo signal received by the probe 4, and the degree of amplification (gain) is set by the preamplifier STC controller 8. 9 is a switcher for arranging the N-channel outputs from the preamplifier 7 so as to obtain the necessary reception focus; 10 is a delay line for applying reception focus; 11 is a switcher for arranging the N-channel outputs from the preamplifier 7 so as to obtain the necessary reception focus; This is an adder for phasing and adding signals. This adder 11 provides a received echo signal with the necessary focus.

This received echo signal is applied to an echo filter 12,
Here, the passing frequency is continuously switched depending on the depth of the object to extract necessary echo signals. After this echo signal is amplified by the log amplifier 13, the ST
The amplification degree and STC are adjusted under the control of the C controller 3. Further, this echo signal is detected by a detector 15, converted to a digital signal by a DSC (digital scan converter) 16, stored in a frame memory, and outputted to a monitor 17 as an ultrasound image. Reference numeral 18 denotes a transmitting/receiving controller for controlling the timing of the entire transmitting/receiving system excluding the DSC 16 and monitor 17.

(Problem to be Solved by the Invention) However, in conventional ultrasonic diagnostic equipment, an ultrasonic image is constructed based on the sensitivity difference between each transducer making up the probe and the difference in the local characteristics of the acoustic lens. Since there is a difference in sensitivity between each ultrasonic rask, there is a problem that brightness unevenness occurs on the screen. That is, as shown in FIG. 7, a partially bright portion A and a dark portion B will appear on the screen displayed on the monitor 17, resulting in a decline in diagnostic performance when performing ultrasound diagnosis.

The present invention has been made in response to the above-mentioned problems.
It is an object of the present invention to provide an ultrasonic diagnostic apparatus that can make the sensitivity of each ultrasonic raster constant.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention has a plurality of ultrasonic transducers arranged in an array, and a plurality of ultrasonic transducers that are combined and transmitted through an acoustic lens. In an ultrasonic diagnostic apparatus having an electronic scan probe that generates each ultrasonic raster, there is a means for measuring the intensity of the received echo signal from the acoustic lens for each ultrasonic raster, and a means for measuring the intensity of the received echo signal from the acoustic lens for each ultrasonic raster, and a means for measuring the intensity of the received echo signal from the acoustic lens for each ultrasonic raster, and The apparatus is characterized by comprising means for controlling the degree of amplification of the received echo signal.

(Operation) The intensity of the received echo signal is measured for each ultrasonic raster,
According to this measurement result, the received echo signal of each ultrasonic raster is controlled so that when the intensity is high, the amplification degree is small, and when the intensity is small, the amplification degree is large. This allows the sensitivity of each ultrasonic raster to be corrected to a constant value, so it is possible to obtain a uniform ultrasonic image without uneven brightness.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the ultrasonic diagnostic apparatus of the present invention, where 4 is an ultrasonic probe having the structure as shown in FIG.
is a changeover switch, 6 is a pulser, 7 is a preamplifier, 8 is a preamplifier STC controller, 9 is a switcher, and 10 is a delay line.

11 is an adder, 12 is an echo filter, 13 is a log amplifier, 14 is an amplifier, 15 is a detector, 16 is a DSC, 17
18 is a monitor, and 18 is a transmitting/receiving controller, and the above configuration and operation are the same as those of the conventional example.

Here, the pulser 6 is driven by the rate signal A shown in FIG. 2 and outputs a driving pulse like B at an arbitrary timing within the interval T, and as a result, the echo signal received by the probe 4 is amplified, delayed, After performing necessary processing such as addition, C
The log amplifier 13 outputs the waveform as follows.

1 is an AGC controller which inputs the echo signal C in the acoustic lens 19 of the probe 4, which is the output of the log amplifier 13, and samples it at the timing of the AGC sampling pulse D applied from the transmission/reception controller 18. Measure signal strength. The timing at which the AGC sampling pulse C is applied is selected to be immediately before the body surface, that is, at the generation timing t at which the echo signal within the acoustic lens is detected. The AGC controller 1 outputs an AGC voltage such as F according to the measurement result. In other words, this AGC voltage outputs a small value (so that the amplification degree becomes small) when the measurement signal strength is large, and a large value (so that the amplification degree becomes large) when the sword constant signal strength is small. Controlled to be output.

The AGC controller 1 is composed of, for example, an integrator, and
The received echo signal C is integrated at the timing of the GC sampling pulse D, and the AGC voltage is determined according to the signal strength of this C. Incidentally, from the transmitting/receiving controller 18, a clock clear pulse for AGC of E is applied to the GC controller 1 in synchronization with the generation timing of the rate signal A.
When the GC clear pulse E is applied, the AGC voltage output from the AGC controller 1 is cleared to 0 level as in the voltage method. And this AGC voltage voltage method AGC
It rises to output a value according to the measurement signal strength depending on the timing of the sampling pulse. After this AGC voltage rises, that value is held until the next ultrasonic raster is generated.

By adding the AGC voltage output from the AGC controller 1 to the adder 2 together with the G STC voltage output from the STC controller 3, the adder 2 outputs an AGC-8TC voltage such as H, which is applied to the amplifier. 14
added to. As a result, the amplifier 14 adjusts the amplification degree (gain) of the received echo signal for each ultrasonic raster.
Control is performed according to the magnitude of C-8TC voltage H. When the voltage H is large, the amplification degree is controlled to be small, and when the voltage H is small, the amplification degree is controlled to be large.

Next, the operation of this embodiment will be explained with reference to the timing chart of FIG.

Drive pulse B from pulser 6 at the timing of rate signal A
By outputting , ultrasonic waves are transmitted from the probe 4 to the subject. The echo signal received by the probe 4 is subjected to necessary processing such as amplification, delay, and addition, and then outputted from the log amplifier 13 as shown in C. This echo signal c is an echo signal within the acoustic lens 19 of the probe 4, and is obtained every time each ultrasonic raster occurs. This echo signal C is sampled by the AGC controller 1 at the timing of the AGC sampling pulse D to measure its signal strength, and the AGC voltage is outputted according to the measurement result.

The AGC voltage is added to the STC voltage G in the voltage multiplier 2, and is applied to the amplifier 14 as the AGC-8TC voltage H. The amplifier 14 controls the degree of amplification of the received echo signal for each ultrasonic raster output from the log amplifier 13 according to the magnitude of the AGC-8TC voltage H. As described above, when the voltage H is large, the amplification degree of the echo signal is controlled to be small, and when the voltage H is small, the amplification degree of the echo signal is controlled to be large. The output echo signal of this amplifier 14 is transmitted to a detector 15. The image is added to the monitor 17 via the DSC 16 and displayed as an ultrasound image.

According to this embodiment, the signal strength of the received echo signals output for each ultrasonic raster is sequentially measured, and the amplification degree of the amplifier is controlled by the magnitude of the AGC voltage according to the measurement result. Therefore, the sensitivity of each ultrasonic raster is corrected to a constant value. Therefore, there is no difference in sensitivity between the ultrasound rusks that make up the ultrasound image, so there is no unevenness in brightness on the screen, making it possible to obtain images with uniform sensitivity, which improves diagnostic performance when performing ultrasound diagnosis. can be improved.

Further, according to this embodiment, since the sensitivity is corrected in real time, the user can correct sensitivity deterioration due to aging of the probe and the transmitting/receiving circuit without having to think about the correction.

FIG. 3 shows another embodiment of the present invention, in which sensitivity correction is performed using an appropriate phantom.

First, with the probe 4 in contact with the phantom 23 as shown in FIG. 4, the AGC sampling pulse D' is applied to the AGC controller 1 as shown in FIG.
sample the echo signal within and measure its signal strength. Then, the AGC voltage G of the AGC controller 1 corresponding to this signal strength at this time is converted into a digital signal by the A/D converter 24 and then stored in the memory 25. By performing the above operations for each ultrasonic raster, the AGC voltage corresponding to each signal intensity is stored in the memory 25.

When performing ultrasound diagnosis of a subject in this state, memory 2
Each AGC voltage F stored in 5 is assigned to raster address A.
By reading the signal in accordance with D, the D/A converter 26 converts it back into an analog signal, which can be used as the AGC voltage. The AGC voltage is added to the STC voltage G and applied to the amplifier 14 as in this embodiment. In this way, this embodiment can also provide the same effects as those of the previous embodiment.

[Effects of the Invention] As described above, according to the present invention, the intensity of the received echo signal is measured for each ultrasonic raster, and the amplification degree of the received echo signal is controlled according to the measurement result. ,
The sensitivity of each ultrasound raster can now be corrected to a constant value,
Uniform ultrasound images without uneven brightness can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the ultrasonic diagnostic apparatus of the present invention, FIG. 2 is a timing chart explaining the operation of this embodiment, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is an explanatory diagram of a preliminary stage of the embodiment shown in FIG. 3, FIG. 5 is a block diagram of a conventional example, FIG. 6 is a perspective view showing an electronic scan probe used in an ultrasonic diagnostic device, and FIG. FIG. 2 is an explanatory diagram of conventional drawbacks. 1... AGC controller, 3... STC controller, 4... Electronic scan probe, 13... Log amplifier, 14... Amplifier,
18... Transmission/reception controller, 19... Acoustic lens, 23... Phantom, 25... Memory.

Claims (1)

[Claims] In an ultrasound diagnostic apparatus having an electronic scanning probe in which a plurality of ultrasound transducers are arranged in an array and each transducer is combined to generate an ultrasound raster through an acoustic lens, an acoustic wave is generated for each ultrasound raster. An ultrasonic diagnostic apparatus comprising: means for measuring the intensity of a received echo signal from a lens; and means for controlling the degree of amplification of the received echo signal of each ultrasonic raster according to the intensity measurement result.