Intra-body cavity ultrasonic observation device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to an electron scanning type intracavitary ultrasonic observation device.

【0002】

[Conventional technology]

Unlike external ultrasonic observation devices, intrabody ultrasonic observation devices are widely used for observing and diagnosing organs such as the stomach and intestines because they are less affected by gas remaining in the body and less reflected by bones. It has come to be used.

【0003】

As such an intrabody ultrasound observation device, a motor drive unit is provided at hand, and the motor drive unit mechanically rotates the vibrator incorporated in the tip portion via the flexible shaft, and super-synchronizes the rotation. An ultrasonic endoscope that transmits and receives sound waves to obtain an image in the circumferential direction, and a convex ultrasonic endoscope that incorporates an array-type transducer at the tip and scans electronically. There is what is called an electronic linear ultrasonic endoscope.

【0004】

[Problems to be Solved by the Invention]

However, in the former ultrasonic endoscope in which the oscillator is mechanically rotated via the flexible shaft, the rotation transmission by the flexible shaft is not stable, and the output image shows image flow and image fluctuation. In addition, in the latter ultrasonic endoscope incorporating an array type oscillator, the number of oscillators is limited due to the limitation of the number of signal lines that can be incorporated in the space of the probe in the body cavity, and the image quality There is a problem that a sufficient ultrasonic image cannot be obtained.

【0005】

The present invention has been made by paying attention to such a conventional problem, and the purpose of the present invention is to signal so that a multi-element array type oscillator can be easily incorporated in a limited space of a probe in a body cavity. It is an object of the present invention to provide an intracoelomic ultrasonic observation apparatus appropriately configured so that a stable image can be obtained by reducing the number of lines and electronically scanning a multi-element array type oscillator.

【0006】

[Means for solving problems]

In order to achieve the above object, in the present invention, a multiplexer arranged in the insertion tip of the probe in the body cavity, a vibrator body formed by arranging a large number of vibrating elements in an array, and a multiplexer for sequentially selecting the vibrating elements, and the multiplexer. A reception amplification unit that inputs and amplifies the output of the vibrating element selected in step 1 via a signal line extending through the intracorporeal probe, an A / D converter that converts the signal into a digital signal, and its digital A wave surface memory that stores signals as wave surface data corresponding to each vibrating element and a wave surface synthesis circuit that performs addition processing based on the output of each wave surface memory are provided.

【0007】

[Action]

That is, in the present invention, the vibrator body and the multiplexer having a large number of vibrating elements are arranged in the insertion tip of the probe in the body cavity, and transmission / reception is repeated while sequentially selecting the vibrating elements of the vibrator body by the multiplexer. The received signal obtained from each vibrating element is taken out via the signal line, stored in the wave surface memory as wave surface data via the reception amplification unit and the A / D converter, and opened in the wave surface synthesis circuit based on these wave surface data. The reflection intensity distribution is obtained by the addition processing by the synthesis method. In this way, if the vibrating elements are sequentially selected by the multiplexer and the transmission / reception is performed in a time-division manner, the signal line of the vibrating element basically needs to be one common line.

【0008】

[Example]

FIG. 1 is a diagram for explaining an aperture synthesis method. In FIG. 1, a wave surface signal from each vibrating element 1-i of the vibrator body 1 having a large number of vibrating elements 1-1, ..., 1-i, ... Is stored in the wave surface memory 2, and this wave surface is stored. The wave surface signal stored in the memory 2 is combined with the wave surface to obtain the output image 3 obtained by converting the original spatial coordinates.

【0009】

In FIG. 1, when an ultrasonic pulse is transmitted from the vibrating element 1-1, the ultrasonic signal is reflected by the reflectors 4a and 4b and stored in the wave surface memory 2 as a wave surface signal 5-1. Similarly, when an ultrasonic pulse is transmitted from the vibrating element 1-i, the reflected signal is stored in the wave surface memory 2 as a wave surface signal 5-i. These wave surface signals 5-1 and 5-i have different waveforms because the spatial positional relationship between the vibrating elements 1-1 and 1-i and the reflectors 4a and 4b is different.

【0010】

Therefore, if the sequential wave surface signals 5-i are combined in the wave surface memory 2 so as to adjust the delay advance of the propagation time between an arbitrary spatial point and each vibrating element 1-i, the beam by the conventional delay circuit is used. Similar to homing, it is possible to detect a reflected signal only in an arbitrary space. This is generally called "Dilay and Sum", and if the wave field to be synthesized is combined for all spaces, the original spatial coordinate-transformed output image 3 can be obtained, and the distribution of reflectors 4a and 4b can be obtained. You can know the situation.

【0011】

Here, it should be noted that the directional characteristics of each vibrating element 1-i alone are wide, and even if sufficient directional resolution cannot be obtained, the directional characteristics of the entire vibrating element group 1 can be sharpened by wave field synthesis. , The directional resolution is improved. From a different point of view, if a wave surface signal is detected while moving a vibrating element with a small opening in a large space and synthesized using all of them, it is as sharp as when a vibrating element with a large opening is used. Since directional characteristics can be obtained, this is called aperture synthesis.

【0012】

FIG. 2 shows an embodiment of the present invention. In this embodiment, the oscillator main body 10 is composed of a large number of vibrating elements 11-1 to 11-N arranged on the same circumference, and is arranged in the insertion tip of the probe in the body cavity. These vibrating elements 11-1 to 11-N were sequentially selected by a multiplexer 12 arranged in the insertion tip portion, and the selected vibrating elements were provided to the outside via a signal line 13 extending through a probe in the body cavity. It is connected to the transmission circuit 14 and the reception amplification unit 15, which transmits and receives ultrasonic waves in a time-division manner. The amplification factor of the reception amplification unit 15 is controlled by the STC control circuit 16 according to the STC voltage according to the elapsed time from transmission, and the output of the reception amplification unit 15 is output by the bandpass filter (BPF) 17 and the A / D converter 18. Then, it is supplied to the multiplexer 19.

【0013】

The multiplexer 19 is controlled by the switching control circuit 20 in synchronization with the multiplexer 12 for selecting the vibrating element, and the received outputs of the vibrating elements 11-1 to 11-N converted into digital signals by the A / D converter 18 by this. Is stored in the corresponding wave surface memory 21-1 to 21-N. The writing and reading of each wave surface data to these wave surface memories 21-1 to 21-N is controlled by the write address circuit 22 and the read address circuit 23, respectively, and the read wave surface data is added to the adder circuit 24 and the log conversion circuit 25, respectively. After that, it is supplied to the digital scan converter (DSC) 26 and displayed on the display 27. The STC voltage in the STC control circuit 16 is controlled in synchronization with the writing by the write address circuit 22, and the addition processing in the addition circuit 24 and the write processing in the DSC 26 are controlled in synchronization with the reading by the read address circuit 23. To do.

【0014】

The operation of this embodiment will be described below. First, under the control of the switching control circuit 20, the multiplexers 12 and 19 are switched to select the vibrating element 11-1 and the wave surface memory 21-1 respectively. In that state, an impulse wave is generated from the transmission circuit 14, the impulse wave is supplied to the vibrating element 11-1 via the signal line 13 and the multiplexer 12, and the vibrating element 11-1 is driven to radiate ultrasonic waves to the living body. To do. The echo of this ultrasonic wave in the living tissue is received by the vibrating element 11-1 and converted into an electric signal (reflected signal), and the reflected signal is appropriately passed through the multiplexer 12 and the signal line 13 by the reception amplification unit 15. After amplifying to the magnitude, it is converted into a digital signal by the A / D converter 18 via BPF17, and this is converted into a digital signal by the A / D converter 18 via the multiplexer 19, and based on the address from the write address circuit 22, it is time-series as wave surface data in the wave surface memory 21-1. Store in.

【0015】

Next, the switching control circuit 20 switches the multiplexers 12 and 19 to select the vibrating element 11-2 and the wave surface memory 21-2, respectively, and the vibrating element 11-2 performs transmission / reception in the same manner, and the reflected signal thereof. Is stored in the wave surface memory 21-2 as wave surface data. The same operation is performed for the other vibrating elements 11-3 to 11-N in sequence, and each wave surface data of the vibrating elements 11-1 to 11-N is stored in the corresponding wave surface memory 21-1 to 21-N. To do.

【0016】

After repeating such processing and obtaining wave surface data from all the vibrating elements 11-1 to 11-N, the wave surface data are added to the addition circuit 24 by the aperture synthesis method of "Dilay and Sum" explained in FIG. The addition process is performed with to reconstruct the image of the intensity distribution of the reflector in each space. Therefore, first, the read address circuit 23 controls the address so that the time axis of the wave surface memories 21-1 to 21-N becomes the equiphase wave surface, and reads out the wave surface data of the wave surface memories 21-1 to 21-N. ..

【0017】

Fig. 3 shows the address relationship for wave field synthesis in the wave field memories 21-1 to 21-N. Fig. 3A shows the reflected signal in the 60 degree direction, Fig. 3B shows the reflected signal in the 120 degree direction, and Fig. 3C shows the reflected signal in the 300 degree direction. The case of synthesizing each is shown. In FIGS. 3A to 3C, the wave surface memories 21-1 to 21-N correspond to the vibrating elements 11-1 to 11 to N from the top to the bottom and the distance from the left to the right. The wave field synthesis in the case of FIG. 3A is performed by adding the data of the equiphase wave planes shown in the figure. Here, the equiphase wave plane is determined by the geometrical positional relationship between each vibrating element 11-i and the spatial points 30a and 30b to be reproduced as shown in FIG. That is, since the propagation time from each vibrating element 11-i to the spatial point is different, the memory address may be adjusted so as to correct this propagation time.

【0018】

In addition, when detecting a reflected signal in the 60-degree direction, the output of the vibrating element behind the oscillator body 10 cannot be used. The output will be used. When applied to Fig. 3A, this means that a signal in the 60-degree direction is synthesized using about 1/4 of the memory. Similarly, when synthesizing signals in the 120-degree direction as shown in Fig. 3B, the range of data used in the memory is shifted and used, and when synthesizing signals in the 300-degree direction, it is shown in Fig. 3C. The data in the memory range shown will be used.

【0019】

The equiphase wave surface for adding the above wave surface data is a kind of hyperbola in which the curvature is large in the short distance portion and the curvature becomes small as the distance increases. Since this wave field synthesis attempts to completely focus on an arbitrary spatial point, it is possible to obtain the same effect as the dynamic focus in the conventional beam synthesis method, and it is possible to obtain the same effect as the dynamic focus in the very short distance part or the long distance part. Deterioration of directional resolution can be reduced in observation.

【0020】

As described above, the data of the equiphase wave plane read by the address from the read address circuit 23 is added by the adder circuit 24 to obtain the intensity of the reflected signal at a certain space point, and the signal is obtained by the log conversion circuit 25. It is detected and compressed and supplied to the DSC26, and the DSC26 converts the coordinate system to match the format of the display 27, and at the same time, performs interpolation between pixels as necessary and outputs it to the display 27. Display a sound image.

【0021】

In the above-described embodiment, a large number of vibrating elements are arranged on the same circumference to form an oscillator main body, but even when the oscillator main body is configured by a convex type or a linear array, the same phase is matched accordingly. The reflection characteristics of the target space can be detected by performing addition processing on the wave surface and synthesizing the wave surface.

【0022】

[Effect of the invention]

As described above, according to the present invention, each vibrating element is selected in a time-division manner for transmission / reception, the wave surface data obtained by this is stored in a memory, and the wave surface is based on the wave surface data. Since the reflection distribution in a predetermined space is obtained by synthesizing, the signal lines can be basically made into one line. Therefore, since the outer diameter of the signal line to the vibrator can be reduced, it can be easily incorporated into the probe in the body cavity. Further, since the number of vibrating elements can be set regardless of the number of signal lines, the number of vibrating elements can be easily increased and the image quality can be improved. Further, when the vibrating elements are arranged on the same circumference, the ultrasonic beam is electronically rotated at a constant speed, so that the problem of image flow and shaking is eliminated and a stable image can be obtained.

[Simple explanation of drawings]

[Figure 1]

It is a figure for demonstrating the aperture synthesis method.

[Figure 2]

It is a figure which shows one Example of this invention.

[Fig. 3]

It is a figure for demonstrating the address relation for wave field synthesis.

[Fig. 4]

It is a figure for demonstrating the geometric relationship between each vibrating element and a space point.

[Explanation of symbols]

10 Oscillator body 11-1 ~ 11-N Vibrating element 12,19 Multiplexer 13 signal line 14 Transmission circuit 15 Reception amplification unit 16 STC control circuit 17 Bandpass filter (BPF) 18 A / D converter 20 Switching control circuit 21-1 ~ 21-N Wave surface memory 22 Write address circuit 23 Read address circuit 24 adder circuit 25 Log conversion circuit 26 Digital Scan Converter (DSC) 27 indicator