JPH0238216B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a probe having a plurality of arrayed transducers to perform focus control on a plurality of adjacent transducers using a delay line. This invention relates to expanding the image display range of an ultrasonic tomography apparatus that transmits and receives an ultrasonic beam into a subject and scans while shifting transducers that are excited almost simultaneously.

[Prior art]

The image display range of the subject in the conventional ultrasonic tomography apparatus using the scanning method described above is, for example, as shown in Fig. 1, with a total number of transducers in the array being 80 (adjacent transducer spacing 1.5 mm pitch). , the number of vibrators excited almost simultaneously is 10 (diameter = 1.5 mm x 10 = 15 mm),
When scanning using the 1/2 pitch scanning method, the scanning line is
140 lines, and at this time, the width of the image display range is 105
mm {=(80−10)×1.5}. Therefore, although the total diameter of the probe was about 120 mm, no image was displayed on each end of the probe, about 7.5 mm apart.

[Problem to be solved by the invention]

In an ultrasonic diagnostic apparatus, if focusing technology is to be adopted in order to uniformly improve the distance resolution of ultrasonic images to a deeper level, it is necessary to increase the aperture. Therefore, for example, the conventional diameter of 15 mm was changed to 27 mm.
(18 oscillators), the size of the image display range becomes 93 mm {=80-18)×1.5}, which is a problem in that it becomes even smaller by 12 mm.
It is possible to compensate for the decrease in the proportion of the image display range due to the increase in the aperture by increasing the number of transducers, but increasing the number of transducers increases the size of the probe, making it difficult to When the child grows up,
There was a problem in that the advantage of being able to operate with one hand was lost.

The present invention has been made to solve the above-mentioned problems, and its purpose is to use a probe formed by arranging n elongated rod-shaped transducers, and to In an ultrasonic tomography apparatus that uses a group of transducers as a block and scans by sequentially shifting the block transducers by a predetermined number of transducers,
It is an object of the present invention to provide a device capable of expanding an image display range without increasing the number of vibrators.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a probe formed by arranging n elongated rod-shaped transducers, and a group of m (m<n) transducers connected to each other among the arrayed transducer group. a switching circuit that sequentially shifts and selects a predetermined number of oscillators as a block;
a focus circuit that focuses an ultrasonic beam by giving an operation delay time to each transducer selected by the switching circuit; and a pulse generating circuit that supplies an ultrasonic ejection pulse to each of the selected transducers; In the ultrasonic tomography apparatus, the ultrasonic tomography apparatus includes a means for displaying an echo signal from within the subject received by the probe as an image on a display, in which t (t<m) transducers are disposed outside the array transducer. The most important feature is that the device includes means for controlling the switching circuit and the focus circuit assuming an array of vibrators.

Further, when the mounting pitch of the array transducers is p, the scanning area is (n+2t-m)×p with respect to the transducer array direction on the front surface of the probe.

The present invention is also characterized in that the relationship between the number of virtual oscillators t and the number m of block oscillators is t=(1/2)m [Operation] The operation will be explained below along with the principle of the present invention.

FIG. 2 is a diagram for explaining the principle of the present invention, where n is the total number of transducers of the probe, p is the scanning pitch, and m is the vibration excited almost simultaneously when the probe transmits and receives one time. The number of children, t, is the number of oscillators in the virtual part.

For the conventional image display width L ₁ , the number of scans is (n-m+
1) Since it is a book, L ₁ = (n-m)×p (1). In the present invention, scanning is performed on the assumption that t additional transducers exist at both ends of the transducer of the probe, as shown in FIG. 2, although they do not actually exist. Therefore, the number of scanning lines is (n+2t−m+
1) Image display width, which is a book and is expressed by the following formula (2)
This means that L ₂ is obtained.

L ₂ = (n + 2t - m) × p ...... (2) In other words, the number of scanning lines is 2t (4t in the case of 1/2 pitch scanning), and the image display range has increased by 2tp, which is a large The image display range can be obtained without changing the size of the probe. Therefore, by appropriately setting m and t, the image display range can be made equal to or greater than that of the conventional method. That is, it is easily understood that if t=0, L ₂ =L ₁ , but if T>0, L ₂ >L ₁ .

However, when transmitting and receiving signals using virtual oscillators, that is, when the number of oscillators excited at almost the same time is less than m, the sensitivity decreases, so correction is required as necessary.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

In addition, in all the figures for explaining the examples,
Components having the same function are given the same reference numerals, and repeated explanations thereof will be omitted.

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

FIG. 3 is a diagram showing the configuration of an embodiment according to the principle of the present invention. In the figure, 1 is a probe, which is composed of n transducers Q ₁ to Q _o and n diode switch groups. The specific configuration of the vibrator section is as shown in _FIG .
A capacitor C and a diode switch D are connected in series to Q ₂ , Q ₃ . . . , respectively, and oscillators Q ₁ , Q ₂ ,
Connection point A between Q ₃ ... and capacitor C is directly grounded by short-circuiting resistor _R1 , and connection point B between capacitor C and diode D is configured to receive diode switching signal DS through resistor _R2 . . Furthermore, an ultrasonic pulse ejection signal US is input to the input terminal of the diode D. 2 is an image amplifier for amplifying the ultrasonic image signal, 3 is a digital scan converter section, 4 is a display device such as a CRT display or television monitor, and 5 is for controlling the diode switch D shown in FIG. A diode switch control circuit, 6 a focus circuit for focusing using a delay line, 7 a pulse generation circuit, 8 a ROM (Read Only Memory) in which data for controlling the diode switch control circuit 5 and the focus circuit 6 are stored. It is.

Figure 5 shows the digital scan shown in Figure 3.
This is a diagram showing a specific configuration of an embodiment of the converter section, in which 301 is an analog-to-digital converter that converts the received signal (analog signal) from the image amplifier 2 into a digital signal, and 302 is a sampling buffer memory for writing. This output signal is stored in the image memory 304 through the serial-parallel converter 303A. serial·
The parallel converter 303A operates at a timing synchronized with the transmission and reception of ultrasonic waves, and the read parallel/serial converter 303B operates at a timing synchronized with a scanning synchronization signal of a television monitor or the like. 305 is image memory 3
04 is an image memory control circuit that controls writing and reading; 306 is a timing control circuit that controls the operation timing of each part of the digital scan converter; 307 is a signal read from the image memory and a position display mark (not shown); A mixer 308 that mixes measured values and the like is a digital/analog converter that converts the output from the mixer 307 into a video signal (analog signal).

Next, the operation of this embodiment will be explained.

3 to 5, when a predetermined address selection signal from the digital scan converter section 3 is input to the ROM 8, a predetermined oscillator selection signal is output from the ROM 8, and the diode switch control circuit 5 and focus circuit 6 is input.
On the other hand, a focusing control signal consisting of a half-wavelength ultrasonic pulse from the timing control circuit _{306 of} the digital scan converter section 3 shown in FIG. A signal for controlling the amount of ultrasonic wave launch delay is input to the focus circuit 6, and the ultrasonic wave launch order and time interval for each predetermined selected vibrator to be excited substantially simultaneously are determined. Further, the diode switch control circuit 5 selects A ₁ to A _t of the probe 1 according to the transducer selection signal from the ROM 8.
Assuming that there are oscillators among B ₁ to B _t (where t<m), an operating state is established in which the number of oscillators excited almost simultaneously is selected and connected. Each of the selected transducers emits an ultrasonic pulse using a pulse generated by the pulse generating circuit 7 in accordance with the delay time determined by the focus circuit 6. This emitted ultrasonic beam is reflected by the subject. This reflected ultrasonic beam is received by each of the transducers, amplified and detected by the image amplifier 2, and then input to the analog-to-digital converter 301 of the digital scan converter section 3, where it is converted into a digital signal and written. serial/parallel converter 3 through the sampling buffer memory 302 for
Input to 03A. The output of this serial/parallel converter 303A is written to the image memory 304 at a predetermined timing.The contents stored in this image memory 304 are synchronized with the scanning synchronization signal of a television monitor, etc. through the parallel/serial converter 303B. It is read out at the correct timing and displayed as an ultrasonic tomographic image on the display device 4 through the mixer 304 and the digital-to-analog converter 308. Repeat this action.

The punched vibrator has A ₁ ~Q _(nt) , A ₂ ~
Q _(n-t+1) , ...Q _(on-1) ~Q _o , ...Q _on ~Q _o+1 ,
...Move Q _(ot) to B _t . This increases the number of scanning lines. This control is performed by using data stored in the ROM 8, as described above. When scanning starts from the left end of Fig. 3, the directivity of the transmitting and receiving beam when there are no transducers A ₁ to A _t actually exists is the center of the group of transducers counted m pieces to the right from the left end of the virtual transducer. in,
The direction is perpendicular to the vibrator array plane.

That is, at the start of scanning, m-t vibrators serve as m apertures, and the apertures gradually increase to m, and then gradually decrease again at the right end. By this operation, if m and t are set appropriately, a number of scanning lines and an image display range equal to or greater than those of the conventional method can be obtained. In this scanning, the transmitting and receiving sensitivity during transmitting and receiving including the virtual oscillator decreases in proportion to (m-t/m) ² , so it is sufficient to correct the decrease using an amplifier.

Although the present invention has been specifically explained above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. .

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to correct the reduction in the image display range even when the ultrasonic transmitting/receiving aperture is expanded, and the image display range can be increased without actually increasing the number of transducers. can.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of a probe of a conventional ultrasonic tomography device, Fig. 2 is a diagram for explaining the principle of the present invention, and Fig. 3 is a diagram showing the configuration of an embodiment of the present invention. FIG. 4 is a diagram for explaining the probe of this embodiment, and FIG. 5 is a block diagram showing the specific configuration of the digital scan converter section of FIG. 3. It is. In the figure, 1... probe, 2... image amplifier, 3...
...Digital scan converter section, 4...Display device, 5...Diode switch control circuit, 6
...Focus circuit, 7...Pulse generation circuit, 8
……ROM.

Claims (1)

[Scope of Claims] 1 A probe formed by arranging n elongated rod-shaped transducers, and m connected transducers (m
A switching circuit that sequentially shifts and selects a predetermined number of transducers by using a group of transducers <n) as a block, and focuses an ultrasonic beam by giving an operation delay time to each transducer selected by the switching circuit. a pulse generating circuit for supplying ultrasonic ejection pulses to each of the selected transducers; and means for displaying the echo signal from the subject received by the probe as an image on a display. In an ultrasonic tomography apparatus, t (t<m) array transducers are virtually set at each end of the array transducer, including this virtually set array transducer. An ultrasonic tomography apparatus comprising means for controlling the switching circuit and the focus circuit. 2 When the mounting pitch of the array transducer is p,
The ultrasonic tomography apparatus according to claim 1, wherein the scanning area is (n+2t-m)×p with respect to the transducer arrangement direction on the entire surface of the probe. 3. The ultrasonic tomography apparatus according to claim 1 or 2, characterized in that the relationship between the number of virtual transducers t and the number m of block transducers is t=(1/2)m.