JPS59214437A - 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] [Technical Field of the Invention] The present invention relates to an ultrasonic diagnostic apparatus for obtaining a one-fold layer of a living body using ultrasonic waves, and particularly relates to an aperture synthesis method using an i-aligned oscillator. This product relates to an ultrasonic diagnostic device that appeals to both people.

[Technical background of the invention and one point of reference] Is it for diagnosing living organisms? 1. There is a sound clinic method. This involves emitting ultrasonic pulses into the body of an insect, and obtaining in-vivo information from the signals reflected from the boundaries of tissues with different acoustic specializations (sound: thickness impedance). This single-site ultrasound examination method can be performed non-invasively, so it does not cause any pain to the examinee, and has the advantage of causing far fewer radiation exposure injuries than X-ray examinations. It has become rapidly popular in recent years because it can easily detect the faults in a tissue.

Based on ultrasonic diagnostic methods, in order to obtain an image with good 1-minute resolution in a conventional device, a 1-term sound beam is focused.In the case of an array-type ultrasound probe, the lateral resolution is improved. Therefore, the relative f(37
At pg, 11H is applied to transmit and receive waves. The so-called electronic exponentiation method is used. Furthermore, the focusing of the ultrasound beam 1)
In order to widen the α region, the focusing position is sequentially moved in the ultrasonic transmission direction 1a,
Dynamic focusing methods and multi-stage focusing methods that improve the li-eye are also known.

In both of these methods, one ultrasonic wave transmission and reception is performed using multiple array-type transducers, and the received signal obtained from each transducer is phased or calculated via a delay circuit. . For the multistage focusing method, the number of frames displayed per second is
As the number of stages increases, it decreases, resulting in poor operability. Furthermore, in the dynamic focusing method, when switching the delay time, signal quintuple continuations, spike noises, etc. occur, deteriorating image quality. In addition, these methods have the disadvantage that if a large number of oscillators are used to obtain high accuracy, the receiving circuit such as a delay circuit becomes complex.

[Purpose of the invention]

The present invention aims to solve the above-mentioned problems and provide an ultrasonic diagnostic apparatus that can easily obtain high-quality ultrasonic waves.

[Summary of the invention]

The ultrasonic diagnostic apparatus of the present invention is made by selecting a combination of a plurality of transducers arranged in one dimension and the transducers to be used for transmission and reception from among these transducers according to a predetermined rule. multiple electronic switches that change the
The apparatus is characterized by comprising a detection means for phase-detecting the received signal obtained by the vibrator, and a processing means for performing correlation processing after averaging a plurality of detected signals obtained by this means. It is.

That is, the present invention emits ultrasonic waves by driving a transmitting transducer among the arrayed transducers in a j-shape, and receives reflected waves from inside the living body using this transducer or another transducer, and transmits ultrasonic waves to a plurality of transducers. By averaging the received signals and then combining them, the influence of variations in the characteristics of each vibrator and the transceiver connected thereto is reduced.

This invention uses the aperture synthesis method for ultrasonic diagnosis, and its principle will be explained with reference to FIG.

In the figure, 1 is a vibrator, and this vibrator 1 is
Ultrasonic waves are transmitted and received in the Z-axis direction while moving in the direction of the arrow I. Now, suppose there is a reflection #-2 at point Pn(Xn, Zn), then the ultrasonic pulse 5t(t) emitted from the transducer 1 at point (x, o)r is reflected at point Pn, The received signal Sr received by the vibrator 1 again is expressed by the following equation.

Sr-γ. f(t-tn) sin (ωo Ct-t
n) ) −・・・−・(1) However.

, and the transmitted ultrasonic pulse 5t(t) is 81(t) = f(t)-si top qt.

Here, ω. -2πfo, fo is the ultrasound center frequency,
γ□ is the reflection coefficient of reflector 2, ■ is the sound velocity in the medium, and f(
t) shows the ultrasound pulse envelope.

The received signal Sr is synchronously detected with a first signal 5ino)ot equal to the ultrasound center frequency fo and a cosine signal t.

Furthermore, the high frequency component (2ω0) is removed by the filter, and the output S becomes as shown by the following equation.

・・・・・・・・・(2) This signal S is correlated with the second reference signal Sc shown below, and a quadrant A(U, Zn) of Pn points is constructed, where jωo(X U)", 9o=exp(-w, 1, so......(4) So, U==Xn+z"zn on the display surface s-z, the reflection Body 2 is displayed.

However, in formula 4) I! Znβ in the middle indicates the integral range.

β is the transmitting and receiving beam width of the transducer 1, and instead of moving one four-axis transducer 1 as described above.

(If a number of brown oscillators are arranged in a row and a part of them is interpreted by an electronic switch, ultrasonic waves can be transmitted and received.

Since high-speed data acquisition is possible, real-time display of ultrasonic tomographic images becomes possible.

In this case, if the same transducer is used for transmission and reception.

Data collection and processing time will be shorter, but if the characteristics of each transducer and the vibration and vibration characteristics and phase characteristics of the transducer connected to it are uneven, it will be difficult to obtain good ultrasound images. Can not.

i7'r 21''4 shows an example of a reconstruction pattern when the degree of variation in the sensitivity of the transducer is used as a parameter. In this pattern, a large side row is a(
It's extremely taboo for beta feelings. The same can be said about variations in phase characteristics.

Therefore, this invention selectively creates a combination of a transmitting transducer and a receiving transducer, and by changing this combination, obtains a large amount of data and averages the data, thereby eliminating the above-mentioned variations in cedar and shore. This eliminates the problem and obtains high-quality images.

Next, the principle will be explained. - As shown in Figure 3, the oscillator A (X-Xd
, o) and the transducer g (x x x d, o) are selected to transmit and receive ultrasonic waves, and if the transducer A is used for transmission and the transducer B is used for reception, then the point Pn (Xn, Zo ) is Sr':r n G t (X xct ) Gr (
X+Xd) f (t t n ) sinωo(”
n) ...................................................... (1'). However, Ut and Or are the transmission and reception sensitivities of the vibrator.

This signal is converted into the first reference signal 5in (ωot+f(Xd)) and cos (ωot
+z(Xd)1 causes a 1i71/11 wave, and its high frequency component (near 2ω) is removed.

exp(-jωotn-)-j/(Xd))-・-(2
A continuous hologram signal is obtained.

Next, change Xd to obtain a signal of 1) p, and when these are accumulated, the integrated signal S'' is exp (-jωo tn+j/(Xd) l d (
Xd)...
d) Gr(X+Xd)−=Gor+ΔGr(X×Xd)
Here, Q, (Jot, Gor) indicates the average transmitting and receiving sensitivity of the vibrator.

Now'-xo t)>△U t y G'r>>ΔG
If r then Gt (X-Xd)-Gr (X0Xd)=
If the Uot Gor reference signal is supplied (2/ //>
The formula is...(2''), and the influence of the variation in oscillatory and infantile sensitivities occurring in formula (2'), that is, the fluctuations △Ut'j6 and △
()r does not appear in the precept (2///), and therefore can be treated as an oscillator of uniform sensitivity.

The fruit is ・・・・・・・・・(3′) becomes.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the five drawings.

71￥4 In the figure, the individual oscillators 11-1 to 11-
N are arranged in a straight line, and each of these is provided with an electronic switch 12-1 to 12-N. A plurality of electronic switches 12-1 to 12-N are camera elements 11-1 to 11-.
This is to select and create a combination of transducers used for transmission and reception from N according to a predetermined rule, and to change this combination.

By controlling the +11 child switches 12-1 to 12-N, one transducer is selected from each of the camera elements 11-1 to 11-N to create a combination, and ultrasonic wave transmission and reception are performed. do waves. Drive pulses from the pulser 13 are supplied to the transducer 1 via the four-element switch 12, and ultrasonic waves are emitted toward the subject. The reflected wave from the subject is received again by 11 of the transducers 11. in this case,
In some cases, the same transducer 11 is used for transmission and reception, but in most cases, different transducers are selected sequentially.

This received signal is supplied to two mixers 14a and 14b, multiplied with the signal from the oscillator 15, and then passed through the counter circuit 32. , 1. is also directly sent to the mixer 14b.

The outputs of the mixers 14a and 14b are filtered by low-pass filters 17a and 17b, respectively, to remove one harmonic component, and then converted into analog-to-digital conversion I! l! ! vessel 18
a, 18b and a storage circuit 20a via digital adders 19a, 19b.

20b and f are stored.

In this case, the signals obtained when transmitting and receiving signals to and from a certain reference oscillator using warm and young children located at equal distances on both sides thereof are sequentially added by digital adders 19a and 19b. It is stored at the digit 1 (address) corresponding to the reference pulser. for example.

The M-th station, j, h child 11-M is used as the base mulberry, and the oscillator/reform to be integrated ['(2//) formula's l is the 4th] is 21L+
Set to 1.

First, transmit and receive data using the camera element 11-■ of Yari■,
this,! :The obtained signal is passed through the means 4-B-H.
FJ2 □Ivf I'fl h each 208.201) predetermined places tq (7 do Iy) j are noted. Next(
ζlV[The signal transmitted by the +1st transducer 11-(M+1) and received by the 1M-1st transducer 11-(M-1) is converted to analog-to-digital converters 18a and 13b.
The adder 19a performs A/D conversion.

In 19b, it is written 'l;r'C times; Raku 20a 20b reads out the previous self 477 ↑ 1st 1st 1st child 11-
The signal from M1 was recorded again 1. () Circuit 20a
, 2Ql) 1-Ii is stored at the location of the said complaint.

Furthermore, (+%i+2.i~4-2)-■-(M+M
The same thing was done for the combination of oscillators ( , , M-MO).

The obtained signals are sequentially added and added to the first circuit 20a.
20b is written at a location corresponding to 11-Ml. However, in this case, the vibrator 1 used for transmission and reception
Each time 1 changes, the phase of the first reference signal sent to the mixers 14a, 14b needs to be controlled by means as described below.

For example, when transmitting and receiving is performed using the M10Mth transducer 11-(M+M.) and the M-('t4oth transducer 11-(M-Mo), the 1Mth transducer 11-M
From these oscillators 11 (M + Mo), 11
If the distance to (f C) is XMo, then the phase of the reference signal is (., +'"1・(XM・)') Phase correction of the reference signal of V: Yes, it is necessary to change it with the distance 2. be.

In this embodiment, such a phase complement E is implemented by a gate circuit 31. This is performed by the counter circuit 32, RIJM 33 and counter circuit 34.

The contents of FIG. 5 will be explained in detail below.

Now, the resonance frequency of the camera elements 11-1 to 11-N is set to 3M[
(z, :!-, then the frequency of the first base i11g is also 3
MHz. ] At A, the counter 32 is 1/1
6 Counter 9 jJ19 call I5 vibration frequency teaching 48
MHz. Oscillation +! The output of i15 is 4ued at a predetermined timing by the gate circuit 31 before being supplied as a clock pulse to the counter 1raku 32. In addition,
This timing is stored in advance in 11%0M33.

, π6 diagram shows a time chart at this time.

lff In Figure 6, C1■ is the output signal of the oscillator 15 ↓ C0
is ((, O+V33 output signal, ■ is the output No. 13 of the gate circuit 31, ■ is the output signal of the counter 32 when all <- so is not done, ■ is the output signal of R, OM 33, i.e. Tsura (Counter 32 when signal D is activated)
shows the output signal of As shown in the figure, 44
Power each time the signal (■ L level) is generated. , the counter circuit 32 is a 1/32 counter, and one oscillator 15
If the oscillation frequency is set to 95 MHz, it is possible to control the phase of the 4T1 reference signal with twice the accuracy.

Note that the counter circuit 34 is for sequentially incrementing the address of the ROM 33, and the number of pixels in the Z direction is 2.
56, an output terminal of 8 bits or more is required. As the spacing between the transducers used for transmission and reception changes,
The output data of ROM 33 must also be changed.

When the input to the memory circuits 20a and 20b is completed in accordance with the reference vibrator 11-M as described above.

The same operation is repeated using the M+1st oscillator 11-(M+i) as the base ω oscillator. In this case, the number used for the 7 bond calculation is M-dove + 1st oscillator 11- (M-dove + 1)
from M + Mo + 1st J oscillator 11- (to 4
up to 10M6+1). Further, the same procedure was carried out for each of the reference vibrators 11-1 to 11-N.

The results are stored in predetermined locations within the memory circuits 20a and 2Ob.

In the signal processing circuit 21, the data stored in the storage circuits 20a, 2Q, and 20b in this manner are convolved with the second reference signal Sc stored in the storage circuit 22 in advance. It will be done. This calculation result is once recorded in the frame memory 23, and then transferred to the digital-to-analog converter 24.4. It is converted and displayed on the television monitor 25, or it is displayed on the X-ray film 26.

The ultrasonic diagnosis 1 new device line of this invention has many 41 transducers.
Since the received 1δ signal is obtained from the 1st combination, it is possible to average out the variations in the characteristics of the transducer elements and the transceivers connected to them, and to prevent the image quality from deteriorating due to the variations.

Furthermore, if the received signals are subjected to additive synthesis after convolution processing, not only will a memory circuit corresponding to the number of combinations of data elements be required, but also the time required for convolution calculation will be longer. This is because the present invention performs additive synthesis of received signals before convolution processing.

Note [This has the advantage of requiring fewer circuits and shortening processing time.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the purpose.

In the present invention, the order in which data is calculated when performing signal subtraction calculation is not limited to that shown in Section 111L'j.

For example, the combination number of the transducers 11 used for transmission and reception (
+VI-M, , M+M0), (M-A4. +1
, M+pigeon+1).

(M Mo+2 + M 10M.+2)...
・・・・・・・・・・・・・・・・・・・・・・・・
(M Mo+1.M+Mo 1 )+ (L~'
IMo+2, M-1-MO).

(”-Mo + 3, M+Mo +1) ・
It is also possible to select in the following order. At this time, the numbers of the reference j oscillators are M, M+i, M+2...
..., and as a result, the same thing as in the above embodiment can be performed.

In addition, the combination numbers of the camera elements 11 used for transmission and reception are set to the same number on the transmitting side, (iVl, M Mn), (M,
M-dove+'); (M+ M”o + 2 )+
It is also possible to select in the order =...=...(IJ, M+MO), and in this case, parallel reception becomes possible, so there is an advantage that the data insertion time can be significantly shortened.

It should be noted that in the above description, it has been stated that variations in the sensitivity of the vibrator can be dealt with by the present invention.

] It goes without saying that the present invention is effective since the same consideration can be applied to variations in the phase of the radial element.

[Brief explanation of drawings]

Figures 1 and 43 +A are explanatory diagrams showing the principle of the present invention, Figure 2 is a characteristic diagram showing the reconstruction pattern when the degree of variation in the sensitivity of the vibrator is used as a parameter, and Figure 4 is an explanatory diagram showing the principle of the present invention. Figure 6 is a block diagram showing the structure of the phase correction means of the embodiment;
The figure is a time chart for explaining the operation of the means. 1... Shake! 1iII child 2...reflector 11
~1~11-N... Vibrator Engineering 2-1~12-N...
・Electronic switch 13...Pulsa 14a,
14b...Mixer control

Claims (2)

[Claims] (1) A number of Mb elements arranged in one dimension, and transmission/reception l from among these 5 Fb elements according to a predetermined rule.
a plurality of d-switches that select and create a combination of j-transitors used in the iT and change this combination; a detection means for phase-detecting the received signal f-detected by the transducer; The device is characterized by a processing means for performing correlation processing after adding and averaging the detected wave number 18 of the 1st summer. (2) The predetermined rule for selecting the transducers used for transmission and reception is to create a combination of oscillators placed symmetrically on both sides of a certain standard oscillator, and to sequentially change this combination. Claim 1: An ultrasonic diagnostic apparatus according to claim 1, characterized in that it includes at least the step of: