JPH01104251A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To obtain a homogeneous ultrasonic image having no density variation between scanning lines, by changing the number of vibrators to be used between at the time of transmission from a vibration element and at the time of reception from the specimen and setting a scanning pitch to 1/2 and bringing directionality to synthetic one of transmission and reception. CONSTITUTION:At the first time, ultrasonic waves are transmitted by vibration elements 1, 2, 3...n and received by vibration elements 1, 2, 3...n-1. At the second time, ultrasonic waves are also transmitted by the vibration elements 1, 2, 3...n and received by vibration elements 2, 3...n. On and after, the vibration elements are shifted by one to similarly execute the operations of the first and second transmitting and receiving cycles by (n) vibration elements 2, 3...n+1. That is, in the first cycle, ultrasonic waves are transmitted by the vibration elements 2, 3...n+1 and received by the vibration elements 2, 3...n and, in the second cycle, ultrasonic waves are transmitted by the vibration elements 2, 3...n+1 and received by the vibration elements 3, 4...n+1. For example, when the number (n) of the vibration elements are set to n=10, transmission is always performed using 10 vibration elements and reception is always performed using 9 vibration elements and the scanning pitch at that time becomes 1/2. Therefore, the enhancement of accuracy and the uniformization of the sensitivity difference between ultrasonic beams adjacent to each other can be achieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic diagnostic apparatus, and particularly to an ultrasonic diagnostic apparatus using the so-called 1/2 pitch scanning method, which aims to improve image quality by increasing the ultrasonic scanning line density. The present invention relates to a sound wave diagnostic device.

[Prior Art] As an ultrasonic diagnostic device, an arbitrary number of vibrating elements of a probe is changed for every repetitive pulse or every arbitrary fixed period to improve the ultrasonic scanning line density by 1/2. A pitch scanning method is known from Japanese Patent Laid-Open No. 52-68775.

[g! The example problem that Akira is trying to solve is that of the 1/2 pitch scanning method described in the above publication.
Since there are differences in output and reception sensitivity between adjacent ultrasound beams, it is difficult to obtain a homogeneous image. The principle will be explained with reference to FIG.

In FIG. 2, 1, 2, 3. ..., n-1, n indicate vibrating elements arranged at equal intervals, 49 holes.

C, 2, HO, HE: Ultrasonic wave transmission using a vibrating element.

Indicates the number of receptions, 1°2.・
..., n-1 vibration elements in the mouth, 1.2.
..., n vibration elements further increase 2,
3. ..., n vibrating elements transmit and receive ultrasonic waves. Therefore, if the center spacing of each vibrating element is 1 pitch (IP).

For each ultrasonic transmission/reception, the ultrasonic beam is 1/2 (1/2
F) Vibration elements are selectively used so as to be shifted by pitch.

That is, in the above conventional technology, when the number of vibrating elements is n=10, as shown in Table 1, the ultrasonic transmission/reception order of Table 1, 1, 2.3, 4.5, and 6 has 9 vibrating elements. Because there are 10 different ultrasonic scanning lines, the transmitting and receiving sensitivity of the vibrating element is different, and if the received signal is displayed as it is, there will be a difference in density between every other ultrasonic scanning line, which naturally results in a uniform image. The problem was that it was not possible to obtain

The object of the present invention is to provide an ultrasonic diagnostic apparatus that improves the density of ultrasonic scanning lines, eliminates sensitivity differences between adjacent ultrasonic beams, and obtains homogeneous ultrasonic images with no shading between displayed scanning lines. Our goal is to provide the following.

[Means for solving the problem] The above purpose is to provide a probe having a plurality of (m) transducers;
n vibrators (where n<m) #1 to #n are sequentially selected while shifting each vibrating element, and the first... A second wave transmission/reception cycle is set, and in the first wave transmission/reception cycle, n selected oscillators #1 to
#n is driven as a whole to transmit waves, and when receiving waves, select transducers #1 to #(n+α) (however, α = +1 or -1) to perform wave reception, and the second transmitting/receiving In the wave cycle, all n selected oscillators #1 to #n are driven to perform wave transmission, and when receiving waves, oscillators #2 to #(n+1+β) (however, in the first wave transmission/reception cycle If α=+1, then β
= +1, and if α = -1 in the first wave transmission/reception cycle, β = -1) to perform wave reception. Ru.

[When the active vibration elements #1 to #n are selected, in the first transmission/reception cycle, waves are transmitted by n pieces #1 to #n, and #1 to #(n-1
). At this time, the directivity of the transmitted wave and the directivity of the received wave are shifted by -pitch. The n-1 overall directional characteristics of transmission and reception are between - and □. That is, <n
1 pitch) is the overall directional characteristic of transmitting and receiving.

Next, in the second transmission/reception cycle, as in the first transmission/reception cycle, waves are transmitted by n waves #1 to #n and received by waves #2 to #n. The directivity of the transmitted wave at this time Therefore, the overall directivity characteristic is shifted by 1/2 pitch between the first transmission/reception cycle and the second transmission/reception cycle. When the vibrating elements are sequentially shifted one by one and scanned, scanning is performed in 1/2 pitch increments. The number of vibrating elements for transmitting and receiving waves in each transmitting/receiving cycle is maintained at n for transmitting and (n - 1) for receiving, so the sensitivity difference in each transmitting and receiving cycle is uniform. becomes.

[Example] Fig. 1 is a diagram for explaining the principle of the present invention, and the same reference numerals as in Fig. 2 indicate the same parts, and the explanation thereof will be omitted. That is, in the first ultrasonic wave transmission/reception cycle, the vibration elements 1.2, 3. . . , n is transmitted, and the wave is received by the vibrating elements 1, 2° 3, . . . , n-1. In the second wave transmission/reception cycle, the vibration element 1° 2.3. ..., n, and vibrating elements 2, 3 . ....

Receive at n. Hereinafter, by shifting the vibrating element by one, the same number of n vibrating elements 2, 3, . ..., the operation of the 1st and 2nd wave transmission/reception cycles is executed at n+1. That is, in the first cycle, the vibration elements 2, 3 . . . , transmits waves with n+1, and vibrates the vibration elements 2, 3 . ..., n, and in the second cycle, the vibration elements 2, 3, . ..., wave is transmitted by n+1, and vibration elements 3 and 4
．． ..., the wave is received at n+1. For example, vibration element n=1
If it is set to 0, 10 vibrating elements are always used for transmitting waves and 9 vibrating elements for receiving waves, and the scanning pitch at that time is 1/2.
becomes. This will be explained in more detail as shown in Table 2.

In Table 2, the numbers of the vibrating elements are shown as element numbers, but
Since n elements are selected, the n elements are #1.
#2. ..., may be indicated by a relative number with #n.

In addition, Figure 3 shows the directivity characteristics during wave transmission and reception based on the above-mentioned principle.As can be seen from the figure, the number of oscillators during wave transmission is n, and the number of oscillators during wave reception is If n-1, when the number of transducers is sufficiently large (when the probe diameter is large)
The overall directivity is the overall directivity Z, which is the center of the directivity X during transmission and the directivity Y during reception. Here, the overall directional characteristic Z is Z=XXY. In Figure 3.

The location where the general directional characteristic Z appears is shown, but the specific form is omitted. This is because it is naturally predictable from z=xxy.

Therefore, as in this embodiment, n vibration elements #1.82
．． . . , #n are sequentially selected, and the first . By employing the second wave transmission/reception cycle, the overall directional characteristic Z is translated by 1/2 pitch. This parallel movement of 1/2 pitch means that the scanning line is 17
This means that the scanning line can be set in 2-pitch increments, which means that a higher-definition image can be obtained than with a 1-pitch scanning line. Furthermore, each transmission and reception is always from n and (n-1) vibrating elements, and there is no change in the number of elements due to each transmission and reception.
There will be no difference in sensitivity.

Next, a specific circuit based on the above-mentioned ultrasonic scanning method will be described in the fourth section.
It is shown and explained in the figure.

In Fig. 4, 11 is a large number of vibration elements (1,2°~I
n? ..., m); 12 is a timing clock signal generator; 13 is a high-voltage pulse generator; 14;
1 is a multiplexer switching control circuit, and 15 is a multiplexer for switching between ultrasonic transmission and reception systems. 16 is a receiving circuit that receives reflected ultrasound when switched to the receiving side by the multiplexer 15, 17 is a receiving output amplifier provided at the output section of the receiving circuit 16, and 18 is a display that displays the receiving output. (CRT), 19 is an X-axis deflection circuit of the display 18, and 20 is a Y-axis deflection circuit.

The input/output waveforms of each part of the circuit shown in FIG. 4 are as shown in FIG. 5, and the operation of FIG. 4 will be explained with reference to the waveform diagram.

A pulse wave is output from the high-voltage pulse generator 13 in response to the input of the clock signal a from the timing clock signal generator D 12, and the output pulse wave is then an [I] level signal from the control circuit 14. C, each vibrating element (1, 2, . . .
..., n). As a result, ultrasonic waves are emitted and reflected waves are obtained from the subject. Immediately after the ultrasonic wave transmission shown in the waveform is completed (point P), the multiplexer 15 is controlled by the control signal C, and the multiplexer 15 is controlled by the control signal C. Only the reflected wave d received by each vibrating element is input to the receiving circuit 16.

Then, the ultrasonic image is displayed on the display 18 via the amplifier 17 and deflected by the X and Y axis deflection circuits 19 and 20.

Immediately before a high voltage pulse is generated by the next clock signal input, the control circuit 14 controls the multiplexer 15 to apply the high voltage pulse only to 1 to n vibration elements. Thereafter, the multiplexer 15 is similarly switched under the control of the control circuit I4, and only the reflected waves d received by each of the 2 to n vibration elements are input to the receiving circuit 16 and displayed on the display 18. In this way, the number of transducers used when transmitting ultrasonic waves from the transducer element and when receiving ultrasonic waves from the subject is changed,
Since the scanning pitch is 1/2 and the directivity is a combination of ultrasonic transmission and reception, the density of the ultrasonic beam is improved and there is no difference in sensitivity between adjacent ultrasonic beams.

In addition, in the above-mentioned embodiment, a case was described in which the number of vibrating elements used during wave reception is one less than the number of vibrating elements used during wave transmission, but the number of vibrating elements used during wave reception is limited to this. The same action and effect can be obtained even if the amount is increased. That is, it can also be realized by selecting one more receiving vibration element. - If it is made into a film, the transmitting oscillator #1. #
2. ....

#n, $1.00 in the first wave transmission/reception cycle.
#2. ..., #(n+α) (however, α=+1 or α=-1), and in the second transmission/reception cycle, #2. #3. ..., 11 (n+1+β)(
However, if α=+1 in the first transmission/reception cycle, β
=+1, and when α=-1 in the first wave transmission/reception cycle, β=-1). This result α=+1. or α=
-1, it is 1/2 pitch scanning, and when α=-1, there are always (n-1) receiving elements, α=+1
In this case, there are always (n+1) receiving elements.

[Effect of the invention] As is clear from the above explanation, according to the present invention, 1/
It is possible to achieve high definition in two-pitch scanning and to equalize the difference in sensitivity between adjacent ultrasound beams, resulting in the effect that a homogeneous ultrasound image can be obtained and the density of ultrasound beams can be improved.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram for explaining the ultrasonic scanning method according to the present invention, FIG. 2 is a principle diagram for explaining the conventional ultrasound scanning method, and FIG. 4 is a circuit configuration diagram showing an embodiment of the present invention, and FIG. 5 is an input/output waveform diagram illustrating the operation of FIG. 4. 11... Ultrasonic vibration element, 15... Multiplexer. Figure 1 A Figure 2 Figure 4

Claims (1)

[Claims] 1. Sequentially select a probe having multiple (m) transducers and n transducers (where n<m) #1 to #n while shifting each transducer, and select each The first and second wave transmission/reception cycles are set for the n number of selected oscillators, and in the first wave transmission/reception cycle, all of the n selected oscillators #1 to #n are driven to transmit waves. When receiving waves, vibrator #1 ~
#(n+α) (however, α=+1 or -1) is selected to perform wave reception, and in the second wave transmission/reception cycle, all of the n selected oscillators #1 to #n are driven. When transmitting waves, when receiving waves, oscillators #2 to #(n+1+β) (however, the first
If α=+1 in the first transmission/reception cycle, β=+1, and β if α=−1 in the first transmission/reception cycle.
1. An ultrasonic diagnostic apparatus comprising: a transducer selection means for selecting a transducer (=-1) to perform wave reception.