JPS6148948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic imaging device used in medical ultrasonic diagnostic equipment, etc., which controls the emission time of transmitted ultrasonic pulses while keeping a group of transducers fixed. It is designed to focus a sound wave beam on a certain point within the subject.

Conventional ultrasound imaging devices using electronic scanning include methods such as linear scanning, sector scanning, and focused scanning. Linear scanning involves arranging an array of transducers in a line and sequentially combining them.
It scans by pulse driving while shifting. On the other hand, sector scanning is a method of changing the traveling direction of the ultrasonic output from the transmitter in a sector shape by controlling the phase of the output pulse from the transducer array arranged in a row. . On the other hand, in focus-type electronic scanning, the emission time of pulsed ultrasonic waves from the piezo array of the transmitter is controlled so that the sound waves arrive at a single point simultaneously and in phase, and then the reflected pulses from that single point are received. After being received by a piezo array of transducers and converted into an electrical signal, an analog delay is applied so that the signals from each piezo overlap at the same time, and then addition is performed to obtain the target signal.

The present invention relates to a device for controlling the emission time of ultrasonic pulses in an ultrasonic imaging apparatus using focus type electronic scanning.

FIG. 1 is a block diagram of an ultrasonic imaging apparatus according to an embodiment of the present invention. In the figure,
1 is a position signal generation circuit within the subject, 2 is a piezo probe position signal generation circuit, 3 is a circuit for calculating the position within the subject and the distance between each piezo probe position, 4 is a voltage value delay amount determination circuit for each piezo probe, and 5 is a circuit for determining the amount of delay in voltage value for each piezo probe. Gate circuit, 6 is timing pulse generation circuit, 7
8 is a delayed pulse generation and piezo probe driving circuit; 9 is one piezo probe; 10 is a pulsed ultrasonic wave emitted from the piezo probe 9 into the subject; 7, 8 ,9
As many circuits 11 as there are piezo probes are required. Reference numeral 12 is an output from the gate circuit 5 and serves as an input to the same delay amount determining circuit as the time value delay amount determining circuit 7. Reference numeral 13 represents a reflected ultrasound wave due to reflection within the subject, and reference numeral 14 represents a piezo probe, which may be the same as the piezo probe 9. 15 is an amplifier, and 16 is an amplification circuit whose amplification degree changes depending on the strength of the reflected wave, which is usually called an STC (sensitivity time control) amplification circuit. Reference numeral 17 denotes an analog delay circuit whose delay amount is given by a signal from the voltage value delay amount determination circuit 4. The same number of combinations 18 of 14, 15, 16, and 17 as the number of piezo probes are installed. 19 is an output from another channel and is connected to another combinational circuit 18
This is the output of 20 is an adder circuit, 21 is a detection circuit, 22 is a monitor TV, 23 is a Z axis (brightness)
Input 24 is the X, Y input. 33 is a piezo position detection device.

FIG. 2 is an explanatory diagram of the operation of the present invention. 25,2
6 are arbitrarily selected orthogonal coordinate systems, with x and y axes respectively. 27 is the area to be viewed, which in this case is in contact with the y-axis 26. 28 is an arbitrary point within the area 27 and its coordinates are (x, y)
shall be. Reference numeral 29 indicates a subject, such as a human body. 30 is a minute piezo probe that is in contact with the surface of the subject 29, and each has a coordinate position (x _i , y _i ).
Here, i indicates the i-th micro piezo probe from the left in FIG.

Piezo probe 9 or 14 in FIG. 1 is the same as piezo probe 30 in FIG. Further, for ease of explanation, the number of piezo probes is assumed to be n. The present invention is a type of electronic scanning in which sound waves are focused on a single point within the subject, represented by a single point 28 in FIG. The coordinates of one point 28 are (x, y) and are on the same plane as the piezo probe group 30.
Coordinates (x _i , y _i ) as a representative of the piezo probe group
Take the i-th one from the left located at . The distance l _i between (x, y) and (x _i , y _i ) is It can be found by In this way, the distances of l ₁ , l ₂ , ...l _o are found, and now with L having the values L≧l ₁ , l ₂ , ...l _o as a reference, L-l ₁ = Δl ₁ L-l ₂ = The values of Δl ₂ L−l ₃ =Δl ₃ : L− _li = Δl _i : L− _lo = Δl _o are determined next. Here, Δl _i always takes O or a positive value.

Assuming that the average sound velocity inside the subject is constant v, in order for the sound waves from the piezo probe group 30 to reach one point 28 at the same time, the delay amount is Δt _i =Δl _i /v ……1. A pulse is created from a reference pulse and applied to each piezo probe.

FIG. 1 shows the above background in a block diagram. In this block diagram, coordinate positions and distances are represented by voltages V. First, the intra-subject position signal generating device 1 generates voltages V _x and V _y corresponding to the position (x, y) of a point within the region 27 in FIG. The area 27 to be viewed in FIG. 2 is divided into l×m pieces. The output from the intra-subject position signal generator 1 is a signal obtained by sequentially scanning the entire region 27 to be viewed. For example, (x ₀ ,
y ₀ ) (x ₀ , y ₁ ) (x ₀ , y ₂ )...(x ₀ , y _n ) (x ₁ , y ₀ )
(x ₁ , y ₁ )... (x ₁ , y _n )... (x _p , y _q )...
If (x _l , y ₀ ) (x _l , y ₁ )...(x _l , y _n ) is to be scanned, the output from the intra-subject position signal generator 1 will be output from two channels, x-axis and y-axis. The time series are (V _x0 , V _y0 ) (V _x0 , V _y1 ) (V _x0 , V _y
2 )...(V _x0 , V _yn ) (V _x1 , V _y0 ) (V _x1 , V _y
0 ) (V _x1 , V _y1 )...(V _x1 , V _yn )... (V _x
p , V _yq )... (V _xl , V _y0 ) (V _xl , V _y1 )...
A voltage signal of (V _xl , V _yn ) is output. In this way, the entire region 27 in which outputs of V _x0 . . . V _xl are to be outputted from the x channel and _{V y0 .} and (V _xp , V _y
The timing of transition from _q ) to ( _Vxp , _Vy(q+1) ) is determined by the timing pulse generator 6. As can be seen from the above description, the signal generation circuit 1 is a staircase wave generation circuit triggered by a pulse from the timing pulse generator 6. The x-axis output V _xp is a staircase wave that changes to V _{x (p+1)} at the same time as V _yn changes to the next V _y0 , and is achieved by a pulse counter and a D/A converter, respectively. Next, the piezo probe position signal generating circuit 2 changes the position (x _i , y _i ) of the piezo probe group 30 shown in _FIG.
This is a circuit that converts it into _i , _Vyi . A piezo position detection device 33 on the shaft 25 is used to detect the position of the piezo probe. The number of piezo position detection devices 33 is n, which is the same as the number of piezo probes, and one device is associated with one piezo probe. The piezo position detection device 33 is shown in FIG. 29 and 30 are the same as in FIG. 2, 31 is a guide rod connected to a piezo probe, and 32 is a linear potentiometer (linear variable resistor) whose resistance value changes depending on the position of guide rod 31. From FIG. 3, the shape of the surface of the object 29 is represented by the resistance value of the linear potentiometer 32. This resistance value is converted into a voltage and used as the y-axis signal yi. On the other hand, since the piezo probes 30 are arranged at equal intervals, the x-axis signal is set to be constant (x _i −x _i-1 ).

As described above, the area 27 is scanned and the distances to each piezo probe 30 are sequentially calculated. This calculation circuit corresponds to 3 in FIG. 1, and the difference Δl _i between the distance l _i from a certain point 28 to each piezo probe 30 and the constant value L
The voltage value ΔV i corresponding to the voltage value ΔV _i is found in sequence. Therefore, the amount of delay is determined by Δt _i =ΔV _i /v. This operation is performed by the voltage value delay amount determining circuit 4, the output of which changes in a stepwise manner in accordance with the clock.

A gate circuit 5 is used to distribute this delay amount (voltage value) to each piezo probe 9. This gate circuit 5 is opened to distribute to each piezo 9. A time value delay amount determination circuit changes this gate output into a time delay amount. The time value delay amount determination circuit 7 is comprised of, for example, a hold circuit (holds the gate output) and a voltage comparator, and determines the delay amount by comparing the clock signal from the timing pulse generation circuit 6 with the hold voltage. A signal corresponding to the amount of delay passes through the pulse generation and drive circuit 8 and excites the piezo 9. The same number of combinational circuits 11, ie, combinations of 7, 8, 9, and 33 as the number of piezos 9 are required.
And the output ultrasound from each piezo is “one point”
converges to. The reflected wave 13 from "a certain point" is received by the piezo 14, and after being amplified by the amplifier 15,
The STC amplification circuit 16 amplifies the signal to the same level as the signal received by the other piezos 14 and adds it to the analog delay circuit 17 .

The analog delay circuit 17 delays the signal from the voltage value delay amount determination circuit 4 so that the signals from each piezo 14 all overlap at the same time. The output from the analog delay circuit 17 is added together with the output 19 from another analog delay circuit in an adder circuit 20, detected by a detection circuit 21, and then displayed on a monitor TV 22.

As described above, the present invention is an electronic scanning ultrasound imaging system that uses a plurality of piezo probes, in which the distance between a fixed point within the subject and each piezo probe is calculated sequentially, and the piezo probe is adjusted to correspond to this distance. This device is designed to be driven with a time delay of 100 to 100 nm, so that focused electronic scanning can be performed with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an electronic scanning ultrasonic imaging apparatus according to the present invention, FIG. 2 is an explanatory diagram of the operation of the present invention, and FIG. 3 is a detailed diagram of a portion of FIG. 1. DESCRIPTION OF SYMBOLS 1... In-subject position signal generation circuit, 2... Piezo probe position signal generation circuit, 3... Distance calculation circuit, 4... Voltage value delay amount determination circuit, 5... Gate circuit, 6... Timing pulse generation Circuit, 7...
Time value delay amount determining circuit, 8... Pulse generation and piezo probe drive circuit, 9, 14, 30... Piezo probe, 15... Amplifier, 16... STC
Amplification circuit, 17...Analog delay circuit, 20...
Addition circuit, 21...detection circuit, 22...monitor
TV, 29... Subject, 31... Guide rod, 32
...Linear potentiometer.

Claims (1)

[Claims] 1 A plurality of piezo probes, a position signal generation circuit within the subject that generates voltages corresponding to a plurality of positions within the subject, and a probe position signal that generates voltages corresponding to the positions of the plurality of piezo probes. a generation circuit, a distance calculation circuit between positions that sequentially calculates the distance between an arbitrary point within the object and the plurality of piezo probes, and a plurality of delay amounts based on voltage values based on the calculation results. A voltage value delay amount determination circuit, a gate circuit that distributes this voltage value delay amount to each piezo probe, a time value delay amount determination circuit that converts this gate output into a time delay amount, and this time delay amount. An electronic scanning ultrasound imaging apparatus comprising: a drive circuit that supplies each of the plurality of piezo probes with a plurality of pulses delayed by a delay time corresponding to the amount of the pulse.