JPS61265132A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Collects and accumulates information on contact conversion efficiency, transmission efficiency, and reception amplifier gain variation, and uses that information to correct transmission power and reception amplifier gain control voltage (current). This is an ultrasonic diagnostic device with a circuit for

[Industrial application field]

The present invention relates to an electronic scanning ultrasonic diagnostic apparatus that is capable of correcting variations in gain of each transmitting/receiving unit with high precision.

[Prior art and problems]

In an electronic scanning ultrasonic diagnostic apparatus, many transceivers are required to transmit and receive a plurality of transducers almost simultaneously. Furthermore, in the receiver, a variable gain amplifier is used to handle everything from large signals to very small signals. Therefore, variations in transmission power, variations in the efficiency of the vibrator, and variations in gain control voltage (current) versus gain of the receiving amplifier occur. For this reason, the combined directivity characteristics deteriorate, resulting in deterioration of resolution. Furthermore, if weighting is to be performed to improve resolution, it is necessary to perform more accurate gain control.

[Purpose of the invention]

The present invention is based on the above consideration, and the transmitter-
The gain of the path consisting of the transducer and receiver is corrected with high precision,
It is an object of the present invention to provide an ultrasonic diagnostic device that can improve resolution.

[Means to achieve the purpose]

Therefore, the ultrasonic diagnostic device of the present invention has an ultrasonic diagnostic device having an ultrasonic transmitter and a receiving amplifier connected to a plurality of ultrasonic transducers constituting a contactor, in which the electroacoustic conversion efficiency of each transducer is and means for collecting variations in system gain caused by variations in gain of the receiving amplifier, and means for correcting the transmission power of each transmitter and the gain of the receiving amplifier based on the information obtained by the means. This is a characteristic feature.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to Examples.

The ultrasonic diagnostic apparatus of the present invention can measure and correct variations. Furthermore, correction of variations can be performed independently for the transmitting section and the receiving section. Measurement and correction of variations will be explained below.

(Measurement of variations in receiving section) FIG. 1 is a diagram illustrating a concept for calibration on the receiving side. In Fig. 1, 1 is a calibration oscillator, 2 is a CPU, and 3 is a calibration oscillator.
is a variable gain amplifier, 4° is a delay line, 5 is an adder, 6 is a detector, 7 is an A/D converter, 11 is a main oscillator, 1
Reference numeral 2 indicates an attenuator, 13 a changeover switch circuit, and A the main body of the ultrasonic diagnostic apparatus. As shown in FIG. 1, remove the contact and connect the calibration oscillator 1 instead. This consists of a main oscillator 11, an attenuator 12 controlled by the CPU 2 of the ultrasound diagnostic apparatus main body A, and a switch circuit 13 that distributes signals to each channel. The calibrated output of the receiving amplifier 3 is passed through a delay line 4, an adder 5, a detector 6, and an A/D converter 7 so that it can be read by the CPU 2. Further, during calibration, the adder 5 is set so that only the output of one channel can be added. During calibration, the CPU 2 changes the input voltage of the receiving amplifier 3 and the gain control voltage vstc, reads the output of the A/D converter 7, and creates a table of V STC vs. gain when the output of the A/D converter 7 is constant. and the non-volatile E described below.
Store it in EFROM21. Perform this operation for all channels.

(Measurement of variations in transmitter) FIG. 2 is a diagram showing the concept of calibration on the transmitting side.

In FIG. 2, 8 represents a contact, 9 represents a reflector, and 10 represents a transmission amplifier. As shown in FIG. 2, the contact 8 is placed facing the reflector 9 in the water. Then, set the main body so that only the first (i=1.2...) channel is used for transmission and reception. Next, VS C is set so that the gain of the receiving amplifier 3 is a constant value (for example, 0 dB). The value of VSTC at this time can be determined from the measurement of the dispersion during reception described above. Next, the voltage V□ applied to the final stage of the transmission amplifier 10 is changed stepwise to measure the received signal voltage.

Furthermore, a table of VH versus voltage at the input end of the receiving amplifier 3 is created using the table created when measuring the dispersion during reception, and this is done for all channels.

Corrections on the transmitting side and the receiving side are performed using the data obtained as described above.

(Correction on Transmission Side) For example, consider a case where 15 channels, CH (channels) 0 to 14, are driven. The maximum voltage is applied to CH7 in the center. Next, a voltage corresponding to the weighting is applied to the surrounding elements. For example, suppose that CH6 and CH8 are given a weight 0.95 times that of CH7 in the center. this is,
Reversely indexing the above table of vll vs. voltage at the input end of the receiving amplifier, the receiving voltage when transmitting at the maximum voltage of CH7 is 0.
．． It is sufficient to give 2, which corresponds to 95 times the received voltage, to CH6 and CH8.

(Correction on Receiving Side) FIG. 3 is a diagram showing the concept of an STC curve, and FIG. 4 is a diagram showing the concept of an STC voltage generation circuit for performing correction on the receiving side. In FIG. 3, the B-mode image is an image obtained when displaying by changing the intensity of reflected waves to the brightness on a cathode ray tube. Also, STC is 5 intensity
It is an abbreviation for Time Control, which means to control the gain of the receiver over time during the sweep to make the display of reflected waves at near and far distances uniform, and the sensitivity for this purpose is It is necessary to select an appropriate value for the degree of change depending on the frequency used and the purpose. In STC, gain correction is performed at several points. In the illustrated example, there are eight points from SWO to SW7 (for example, 2 cm, 4 cm, and 6 cm from the body surface).
, -16cm), and their sensitivities are so, sl, ·
...It is set as sl. In FIG. 4, 17 is a latch;
18 and 19 are adders, 20 is a decoding RAM, and 21 is E[! PI? OM, 22 is D/A converter, 23 is LPF
are shown respectively. As shown in FIG. 3, the STC information is obtained as switch information. Uncorrected STC value S for the j-th division section of the section i of the n-th channel
ゎ(i, j) becomes . The weights W and l are obtained by decoding the scanned green shade using the decoding RAM 20, as shown in FIG. Therefore, the weighted required gain G7(i,j) is Q1l(i,j) = Wn ·Sn (IIJ
). W, , and Sn are connected to the input of the EEFROM 21 in which the table of vs'rc vs. gain is stored, and the corrected output becomes the input of the D/A converter 22, where it is converted to an analog voltage and passed through the LPF 23 to each channel. STC of
The voltage becomes V 37 c.

In the above embodiment, weighting is applied, but it goes without saying that the present invention can also be applied to a case where weighting is not applied.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, gain errors between each channel can be canceled out, accurate weighting can always be performed no matter what STC changes, and ultrasonic waves with good resolution can be generated. You can get the image.

[Brief explanation of drawings]

Figure 1 is a diagram showing the concept for calibration on the receiving side, Figure 2 is a diagram showing the concept for calibration on the transmitting side, Figure 3 is a diagram showing the concept of STC curve, and Figure 4 is a diagram showing the concept for calibration on the receiving side. 2 is a diagram illustrating the concept of an STC voltage generation circuit for correcting. FIG.

Claims (1)

[Claims] In an ultrasonic diagnostic apparatus having an ultrasonic transmitter and a receiving amplifier connected to a plurality of ultrasonic transducers constituting a contactor, a system caused by variations in the electroacoustic conversion efficiency of each transducer and the gain of the receiving amplifier 1. An ultrasonic diagnostic apparatus comprising: means for collecting variations in gain; and means for correcting the transmission power of each transmitter and the gain of a receiving amplifier based on the information obtained by the means.