JPH0636799B2 - Ultrasonic diagnostic equipment - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus.

[Technical background of the invention] In recent years, an ultrasonic diagnostic apparatus has a phased array transducer and electronically focuses an ultrasonic beam to obtain a high-resolution ultrasonic tomographic image. . The basic configuration of these ultrasonic diagnostic apparatuses is shown in FIG. First, the basic operation of this device will be described. First, a clock signal from a reference clock generator 1 that generates a reference signal for transmitting an ultrasonic pulse is added to the transmission delay circuit group 4. Further, the delay data generated by the transmission delay data generator 3 based on the signal from the focus point setting device 2 is also added to the transmission delay circuit group 4. The transmission delay circuit group 4 receives the clock signal and the delayed data, generates N pulse signals different in time, and sends them to the transmitter group 6. The transmitter group 5 converts the received pulse signal into a high-voltage pulse signal and excites the vibrator group 6. As a result, ultrasonic waves are radiated, and echo signals from parts of the living body having different acoustic impedances are received by the same transducer group 6 and converted into electrical signals. Next, in order to protect the receiving circuit in the subsequent stage from the transmission pulse having the high voltage signal amplitude, the signal is obtained by passing through the limiter group 7. Since this received signal is weak, the preamplifier group (preamplifier group) 8 amplifies the signal amplitude. Next, the reception delay data generator 9 generates data delayed by a predetermined time with respect to the focus point set by the data of the focus point setting device 2, and the reception delay circuit group 1
Give to 0. The reception delay circuit group 10 gives a delay time to the received signals amplified by the preamplifier group 8 so that they are in phase with each other based on the delay data, and then adds them.
Then, the output of the reception delay circuit group 10 is added to the video circuit 11, detection is performed therein, and the signal is further passed through the envelope filter. Next, in addition to the ADC 12 which converts an analog signal into a digital signal, the digital signal is converted into a DSC here.
Add to 13. DSC (Digital Scan Converter)
Reference numeral 13 performs scan conversion for displaying the ultrasonic raster on the TV monitor. The digital signal output from here is converted into an analog signal by the DAC 14, and the TV monitor 15
To display an ultrasonic tomographic image. In the system having such a basic configuration, the number of transducers forming one beam has been increasing year by year in recent years in order to increase the resolution and reduce the side lobes (gray-ten-groove) of the ultrasonic beam. Here, it is known that the beam width of the ultrasonic beam at the focus point is determined by W = K · λ · L / D as shown in FIG. Here, W = beam width of focus point, K
= Coefficient determined by the shape of the vibrator, λ = wavelength at the center frequency of the ultrasonic wave, L = distance from the surface of the vibrator to the focus point, D = diameter of the vibrator. Thus, in order to narrow the beam width, it is necessary to widen the diameter of the transducer or increase the ultrasonic frequency. However, since the amount of attenuation of ultrasonic waves is proportional to the frequency, increasing the frequency of ultrasonic waves increases the amount of attenuation inside the living body, making it impossible to display a deep image.
Further, if the number of divided elements is fixed and the aperture is increased, the gratin gloves become large. In order to make the GRATEIN glove smaller, the element width of the vibrator that constitutes the aperture must be narrowed. Here, the relationship between the divided oscillator width and the generated gray veins is
Shown in the figure. In the diagram of FIG. 2, the Greateine Grove in which the direction of the main beam is e is generated in the directions of cl and cr. The angle θ is represented by θ = ± SIN ₋₁ (λ / d + SIN θo). Where θo = deflection angle of main beam, d
Indicates the element spacing of the vibrator. As described above, when the width of the divided oscillator is narrowed, the angle θ becomes large, and the peak power thereof is reduced accordingly. However, if the width of the divided oscillator is narrowed and the diameter of the divided oscillator is increased, the scale of the circuit is increased and the system becomes very expensive. In particular, the ratio occupied by the reception delay circuit is high. In recent years, a method of dynamically moving the focus point at the time of reception has been generalized, which makes the circuit complicated and expensive. Therefore, it is desired to reduce this circuit portion in the ultrasonic system.

[Problems of the Background Art] As described above, in the ultrasonic diagnostic apparatus, if the divided oscillator width is narrowed and the aperture is increased in order to increase the resolution of the ultrasonic beam and reduce the side lobe (grating lobe), This causes a problem that the circuit scale becomes large and the system becomes very expensive. In particular, the ratio of the price of the reception delay circuit to the system price is high.

This is because a method of dynamically moving the focus point at the time of reception has been generalized in recent years, which makes the circuit complicated and expensive.

[Object of the Invention] The present invention has been made to solve the above-mentioned problems, and S / N and a S / N for a diagnosis site (abdomen, obstetrics and gynecology, etc.) that does not pose a problem even if the number of frames is practically dropped. It is intended to reduce the size and cost of the ultrasonic diagnostic apparatus by reducing the number of frames without reducing the resolution and reducing the circuit scale of the reception delay circuit by the reduced amount. is there.

[Summary of the Invention] In order to solve the above problems, the present invention provides an ultrasonic diagnostic apparatus including a transducer group in which a plurality of ultrasonic transducers are arranged in an array form or a matrix form. A switching circuit group for dividing an oscillator group into several blocks by RATE of a repeating cycle so that an ultrasonic beam corresponding to a plurality of oscillator groups N is formed, and the switching circuit group includes several blocks. A reception delay circuit that sets a delay time required to form an ultrasonic beam corresponding to the transducer group N in the above-described transducer group and a signal obtained by the divided transducer group are stored respectively. It is characterized by including a line memory group and an adder for adding the outputs of the memory groups.

Embodiments of the Invention The present invention will be described in detail below with reference to illustrated embodiments.

FIG. 1 is a circuit block diagram showing a specific example of the present invention.
In the embodiments of the present invention, circuit blocks having the same functions as those of the conventional ultrasonic diagnostic apparatus shown in FIG. 7 are designated by the same reference numerals, and a new description will be omitted. The circuit added to the apparatus shown in FIG. 1 in comparison with the ultrasonic diagnostic apparatus shown in FIG. 7 is composed of a CPU 16 that creates control data of a transmission / reception circuit and a simultaneous reception transducer that forms one raster of ultrasonic waves. A switching unit 17 for selecting the divided groups, a reception delay data generator 21 for generating delay data necessary for forming one raster for the divided transducer groups, and a reception delay circuit group 10 The ADC 18 for converting the RF analog signal which is the output of the above into a digital signal, the line memory group 19 necessary for forming one raster, and the wave detector 20 for obtaining the absolute value of the output signal of the line memory group 19.

FIG. 2 illustrates the configuration of the line memory group 19 of FIG. 1 in more detail. Here, 19-1 is a tri-state buffer, 19-2 is a RAM, 19-3 is an adder, 19-4 is a gate circuit 19-5 is a write / read gate signal generator, and 19-6 is an address generator. It is a vessel.

FIG. 3 shows a method of selecting transducer groups required to form one ultrasonic raster by 2 RATE.

FIGS. 4A and 4B show the reception selection circuit time given to each transducer group in FIG.

FIG. 5 shows details of a block diagram of the line memory group 19 in FIG. 1 for forming one raster of ultrasonic waves by 3RATE.

FIG. 6 shows a method of selecting a transducer group necessary for forming one ultrasonic raster by 3RATE of FIG.

Here, the operation of one embodiment of the present invention will be described. In order to simplify the basic operation, the operation will be described by taking as an example a configuration in which one raster of ultrasonic waves is formed by 2 RATE, that is, the number of transmissions is 2. Further, the most popular ultrasonic diagnostic apparatus including an array transducer is a linear scan and a sector scan apparatus, but since the basic configuration is the same, the configuration of the sector scan apparatus will be described here. To do. The circuit blocks having the same functions as those of the conventional ultrasonic diagnostic apparatus of this embodiment shown in FIG. 7 are designated by the same reference numerals, and a new description is omitted here. In addition, the number of transmitting transducers forming one raster is 4
The number of elements and the number of receiving transducers will be described as 8 elements. First, at RATE 1, data of the focus point of the transmission beam is output from the CPU 19, and the data is given to the transmission delay data generator 3. The transmission delay data generator 3 generates delay data and gives the transmission delay data to the transmission delay circuit group 4. This transmission delay circuit group 4 outputs a pulse signal provided with a delay time such that each of the transmission oscillators matches the wave front of the sound wave at the transmission focus point. This signal is converted by the transmission circuit group 5 into a high-amplitude signal necessary for exciting the vibrator. Transducer 6-3 as shown in Fig. 3
To 6-6. In FIG. 3, LA is a raster, RA is a RATE, T is a transmitting oscillator, and R is a receiving oscillator. In addition, in the figure, the shaded portion indicates the vibrator to be used. The echo signals from the subject are received by the transducers 6-1 to 6-8 by these transmitted sound waves. The signal is applied to the switch group 17 through the limiter group 7. Here, the R of FIG.
Like A1, the signals from the four elements of the transducers 6-1 to 6-4 are first selected. Next, the signal is amplified by the preamplifier group 8 and added to the reception delay circuit group 10. In this reception delay circuit group 10, a delay time is given to each signal so that the wavefront matches the reception focus point. FIG. 4 shows how to give this delay time. In FIG. 4 (a), a delay time is given to a received signal corresponding to each transducer in order to perform beam deflection and focusing with eight transducers in the related art. FIG. 4 (b) shows the fourth embodiment of the present invention.
It shows how to give a reception delay time for obtaining an ultrasonic beam equivalent to that in FIG. In FIG. 4, the horizontal axis T
d represents the delay time, and the vertical axis represents the element number of the vibrator. In this way, first, the transducers 6-1 to 6-4
Then, the same delay times Td1 to Td4 as those in FIG. 4 (a) are given, and the respective delay times are added and output from the reception delay data generator 10. The signal is converted into a digital signal by the ADC 18 and added to the line memory group 19. ADC1
The clock signal 8 has a frequency that is at least twice the maximum frequency of the frequency band of the ultrasonic reception signal. The line memory group 19 has the circuit configuration shown in FIG. 2. The write / read gate signal generator 19-5 generates a write gate signal to bring the tri-state buffer 19-1 into a conductive state. That is, the output signal h of the ADC 18 is transferred to the RAM 19
Give to -2. Next, with the clock signal f from the reference signal generator 1 and the signal g from the CPU 16, the address generator 1
9-6 generates the address signal of the RAM 19-2,
One RATE of the received signal is stored in the RAM 19-2.
At this time, the gate circuits 19-4 and 19-7 are in the off state, and no signal is output from each. Up to this point, the operation of the first RATE1 is completed. Next, RA
In TE2, similarly to RATE1, the transmission delay data generator 3, the transmission delay circuit group 4, and the transmitter group 5 apply the excitation pulse to the similar transducers 6-3 to 6-6 by the transmission focus data of the CPU 16. The received signal obtained thereby is passed through the limiter group 7, and RA of FIG.
The transducers 6-5 to 6-8 are selected by the switch group 17 as indicated by R in FIG. The signal selected here is passed through the preamplifier group 8 and given to the reception delay circuit group 10. In the reception delay circuit group 10, as shown in FIG. 4 (b), a delay time of Td5-Td0 is given to the signal given to the vibrator 6-5. Where T
d0 controls the memory data in the line memory group 19 in the subsequent stage to give a delay time equivalent to Td0. As a result, the maximum delay time required in the reception delay circuit group 10 is reduced and the circuit scale is reduced. Thus, the other transducers 6-6 have Td6-Td0 and 6-7 have Td7-.
A delay time of Td8-Td0 is given to Td0 and 6-8. The respective signals thus obtained are added by the adder of the reception delay circuit 10, and the signals are given to the line memory group 19 through the ADC 18. Line memory group 19
Then, the write / read gate signal generator 19-5 generates a read gate signal by the signals f and g, turns off the tri-state buffer 19-1 and puts the RAM 19-2 into the read state, and the gate circuits 19-4 and 19-7. To turn on. Next, in the address generator 19-6, the RAM 19-2
Generates the read address of. This address signal is achieved by advancing the reading of the data of the RAM 19-2 by the address corresponding to Td0 so as to give the delay time corresponding to Td0 shown in FIG. 4 (b). The signal read here is passed through the gate circuit 19-7. On the other hand, the signal from the ADC 18 is supplied to the gate circuit 19-
Pass 4. This allows the gate circuits 19-7 and 19
The output of -4 is added by the adder 19-3 and becomes the output signal K of the line memory group 19. This signal corresponds to an ultrasonic beam consisting of 8 transducer elements in FIG. 4 (a). next,
This signal K is given to the detector 20 to take an absolute value, and DSC
Give to 13. In the DSC 13, the display 15 is a TV
-Scan conversion for display on the monitor, conversion into an analog signal by the DAC 14, and display on the display unit 15. In this embodiment, one beam of ultrasonic waves is formed by 2 RATE, but the present invention is not 2 RATE but several RATE.
Even in the mode in which one beam is formed, the selection can be easily achieved by dividing the selection of the switch 17 and adding the line memory 19 and peripheral circuits.
FIG. 5 shows the configuration of a circuit for forming one beam in 3 RATE. The method of selecting the vibrator at this time is shown in FIG. In FIG. 5, 20-1 is a tri-state buffer 1, 20-2 is a RAM 1, 20-3 is a tri-state buffer 2, 20-4 is a RAM-2, 20-.
5 is a gate circuit 3, 20-6 is an adder, 20-7 is a write / read gate generator, 20-8 is an address generator, 2
Reference numeral 0-9 indicates the gate circuit 1, and 20-10 indicates the gate circuit 2. The signals in FIG. 6 are the same as those in FIG. This circuit operation excites the vibrators 6-3 to 6-6 by RAI (1 RATE) shown in FIG. The received signal by it is switched 17
Select the receiving oscillators 6-1 to 6-3 with. As described above, the signal is supplied to the preamplifier group 8 and the reception delay circuit group 1
0, it is given to the circuit of FIG. In the circuit shown in FIG. 5, write / read gate generator 20-7 turns on tristate buffer 20-1 by signals g and f, and RAM (1) 20-2 receives the address signal of address generator 20-8. Store received data. At this time, the tri-state buffer 20-
3, gate circuit (3) 20-5, gate circuit (1) 20
-9, the gate circuit (2) 20-10 is in the off state.
Next, as in RA2 in FIG. 6, the transmission beam excites the same oscillator as in RA1, and the signals from the oscillators 6-4 and 6-5 are selected by the switching group 17 at the time of reception. The signal is written and read by the gate generator 20-7 through the tristate buffer (2) 20-3 of FIG.
Store at -4. At this time, the tri-state buffer (2) 20-1, the gate circuit (3) 20-5, the gate circuit (1) 20-9, and the gate circuit (2) 20-10 are off. Next, as in RA3 of FIG. 6, the transmission beam excites the same oscillator as RA1, and at the time of reception, the switching group 17
Then, the signals from the vibrators 6-6, 6-7, 6-8 are selected, and the signals are passed through the gate circuit (3) 20-5 of FIG. At this time, the tri-state buffer (1) 20-1 and the tri-state buffer (2) 20-3 are in the off state, and the gate circuit (1) 20-9 and the gate circuit (2) 20
-10 is in the on state. At this time, the address generator 20-
RAM (1) 20-2, RAM (2) 20
The data stored in -4 is read. These RAM
The adder 20-6 adds the output signals of the (1) 20-2 and the RAM (2) 20-4 and the signal from the gate circuit (3) 20-5. As a result, in 3RATE, FIG. 4 (a)
It can form the same receiving beam as.

[Advantages of the Invention] As described above, according to the present invention, in order to form the ultrasonic beams corresponding to the plurality of transducer groups N at the time of reception, at the RATE of a plurality of ultrasonic repetition periods at the time of reception, A switching circuit group that divides the transducer group into several blocks; a reception delay circuit group that sets the delay time required to form an ultrasonic beam corresponding to the transducer group N by the divided transducer group; By providing a line memory group that stores the signals obtained thereby and an adder that adds the outputs of these memory groups, it is possible to reduce the number of frames practically at a diagnosis site (abdomen, obstetrics and gynecology, etc.). It is possible to reduce the size and cost of the ultrasonic diagnostic apparatus by reducing the circuit scale of the reception delay circuit by the reduction in the number of frames without lowering the S / N and resolution.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention, and FIG. 2 is
FIG. 4 is a block diagram showing the internal configuration of the line memory group of FIG. 1, and FIG. 3 is an explanatory view of a transducer group selection method required to form one raster of ultrasonic waves in 2RATE, FIG.
4 and FIG. 4 (b) are explanatory views showing the reception delay time given to the reception signals corresponding to the transducer groups shown in FIG. 7 and FIG. 1, and FIG. 5 shows one raster of ultrasonic waves at 3 RATE. Block diagram showing the internal configuration of the line memory group for forming,
FIG. 6 is an explanatory view showing a method of selecting a transducer group required to form one raster of ultrasonic waves by 3RATE of FIG. 5, and FIG. 7 is a block diagram showing an example of a conventional ultrasonic diagnostic apparatus. ,
FIG. 8 is a diagram showing the relationship between the transducer aperture and the ultrasonic beam in the array transducer, and FIG. 9 is a diagram showing the relationship between the element pitch interval of the array transducer and the grating grove generated thereby. 6 ... Transducer group, 10 ... Reception delay circuit, 17 ... Switching circuit, 19 ... Line memory, 19-3 ... Adder.

Claims (1)

[Claims] 1. An ultrasonic diagnostic apparatus comprising a transducer group in which a plurality of ultrasonic transducers are arranged in an array or a matrix, and a RATE of a plurality of ultrasonic repeating cycles at the time of reception.
And a switching circuit group that divides the transducer group into several blocks so that ultrasonic beams corresponding to the plurality of transducer groups N are formed, and the switching circuit group is divided into several blocks. A reception delay circuit that sets a delay time required to form an ultrasonic beam corresponding to the transducer group N in the transducer group, a line memory group that stores signals obtained by the divided transducer groups, respectively. An ultrasonic diagnostic apparatus comprising: an adder that adds outputs of the memory groups.