JPH0555138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic stone crushing device that crushes a stone within a subject using focused ultrasonic energy.

(Prior Art) In recent years, devices that use shock wave energy to crush stones within a subject have been put into practical use.

This device places a subject with a stone in a container of a predetermined size and filled with water at an appropriate temperature, and aligns the position of the stone with the focal point of one of the spheroids. At the other focal point, a shock wave is generated by the explosion or discharge phenomenon of gunpowder, and a spheroidal acoustic mirror placed around the shock wave is focused on the calculus, so that the shock wave energy crushes the calculus. This is what I did.

In this case, confirmation of the location of the stone in the subject is performed while displaying the stone portion using an X-ray fluoroscope placed outside the container.

(Problem to be Solved by the Invention) However, when the above-mentioned device repeats the crushing action tens to hundreds of times, the gunpowder and electrodes must be replaced each time a shock wave is generated, which requires a lot of time. There are problems in that it requires a lot of time and costs a lot.

In addition, in the case of this apparatus, it is troublesome to place the subject in a container filled with water, and furthermore, since observation using X-ray fluoroscopy is essential, the amount of radiation exposure to which the subject and the operator are exposed cannot be ignored.

Furthermore, there is a problem that the device becomes large-scale and extremely expensive.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an ultrasonic stone crushing device that can accurately destroy stones in a subject without any risk of exposure to X-rays, and that is inexpensive. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) The outline of the present invention for achieving the above-mentioned object is as follows: an ultrasonic transducer;
a second ultrasonic transducer arranged in a predetermined positional relationship with the first ultrasonic transducer to form a sound field region including the focal point to obtain tomographic image data of the subject; a display means for displaying a focal point marker corresponding to the focal point in a tomographic image based on tomographic image data; and a display means for detecting a reflected echo signal of the ultrasound emitted from the first ultrasound transducer due to the stone. , and display position determining means for determining the display position of the focal point marker based on the information.

(Function) According to the above configuration, by displaying the focal point marker in the tomographic image, positioning can be ensured and appropriate calculus fragmentation can be performed.

(Example) Examples of the present invention will be described in detail below. 1st
The embodiment shown in the figure has a first
An applicator 3 including second ultrasonic transducers 1 and 2, and a first ultrasonic transformer that sends two types of strong and weak pulse signals to the first ultrasonic transducer 1. juusa 1
A first signal processing system 4 receives and processes an ultrasonic echo signal from a first signal processing system 4, and a pulse signal is sent to the second ultrasonic transducer 2 to generate ultrasonic waves and scan in a fan shape. A second signal processing system 5 receives and processes the ultrasonic echo signals from the second ultrasonic transducer 2, and a CPU (central processing unit) controls each part of this device based on predetermined parameters. a control system 8 consisting of a controller 7 that is controlled by the CPU 6 and controls the transmission/reception timing, amplitude, frequency, etc. of pulse signals in the first and second signal processing systems 4 and 5;
A second signal processing system 5 controlled by the CPU 6
a signal conversion system (for example, a digital scan converter) 9 that performs signal conversion processing on the output signal of the
Based on the output signal of the signal conversion system 9, the second ultrasonic transducer 2 generates a fan-shaped sound field area 31, a body surface image 33 of the subject, a kidney image 34, and a kidney stone image as shown in FIG. Display means 1 such as a TV monitor that displays the position 36 of the first ultrasonic transducer 1 such as 35, the sound field area 37, the focal point marker 38, etc.
0, a stone position confirmation means 11 such as a speaker for confirming the position of a kidney stone within the subject based on the output signal of the first signal processing system 4, and a stone position confirmation means 11 such as a speaker capable of contacting a part of the subject, for example, a limb, etc. A subject signal detection element 12 that is formed and sends a subject signal indicating heartbeat of the subject to the CPU 6, and a pulse signal that is sent from the first signal processing system 4 to the first ultrasonic transducer 1. A pulse generation switch 13 consisting of first and second push buttons connected to the CPU 6 to set the timing, and a sound speed switch 13 connected to the CPU 6 to vary the ultrasonic sound speed set value during signal conversion in the signal conversion system 9. The configuration includes a setting means 14. Next, the specific configuration of the applicator 3 will be explained. The first ultrasonic transducer 1 has a resonant frequency of 1 MHz, for example, and has a hole of a predetermined shape in the center as shown in FIG.
It consists of a concave vibrator 15 having a curvature of 10 cm in diameter and a backing material 16 uniformly adhered to the back surface of the concave vibrator 15, and a first cable 17 is connected to an electrode (not shown) of the concave vibrator 15. ing.

The second ultrasonic transducer 2 is a sector probe that is fixed in the hole and has a transducer array 2a formed by arranging thin transducers facing the curved surface of the concave transducer 15. A second cable 18 is drawn out from the sector probe.

The outer periphery of the first ultrasonic transducer 1 is supported by a fixed frame 20 having a shaft 19, and this fixed frame 20 is coupled to an arm 21 to move the first ultrasonic transducer 1 and the second ultrasonic transducer 1. The ultrasonic transducers 1 and 2 can be moved to a desired position and fixed at that position.

the first and second ultrasonic transducers 1;
2 connects the body surface 33M of the subject with the acoustic coupler 22.
acoustically coupled to the This acoustic coupler 22
As shown in FIG. 2, a bag 23 formed of a thin film having an acoustic impedance approximately equal to that of water;
This bag 23 is filled with water 23a, and by arranging this acoustic coupler 22 on the sound field side of the first and second ultrasonic transducers 1 and 2, Ultrasonic waves are efficiently transmitted and received between the two ultrasonic transducers 1 and 2 and the subject.

Next, the first signal processing system 4 will be explained. The first signal processing system 4 includes a controller 7 of the control system 8.
and sends two types of pulse signals of large amplitude and small amplitude to the first ultrasonic transducer 1 via the first cable 17.
a pulser 25 that excites the ultrasonic transducer 1 to generate two types of strong and weak ultrasonic waves;
A receiving circuit 25 receives an echo signal based on a weak ultrasonic wave transmitted from the first ultrasonic transducer 1 to the subject via the first cable 17, and the output signal of this receiving circuit 25 is input. It is comprised of a first signal processing circuit 26 that converts this into an audio signal of an audible frequency and sends it to the stone location confirmation means 11.

Next, the second signal processing system 5 will be explained. The second signal processing system 5 is controlled by the controller 7 of the control system 8, and sends a pulse signal to the second ultrasonic transducer 2 at a predetermined timing. a transmitting/receiving circuit 27 that excites the ultrasonic transducer 2 to perform a sector scan and receives an echo signal from the second ultrasonic transducer 2 based on the sector scan.
and a second signal processing circuit 28 which inputs the output signal of the transmitter/receiver circuit 27, performs amplitude detection on it, and sends it to the signal conversion system 9 as a video signal.

Next, the basic operation of the apparatus having the above-mentioned configuration will be explained using as an example a case where a kidney stone 35M in a kidney 34M in a subject is crushed.

First, the acoustic coupler 22 supported by the fixed frame 20 of the applicator 3 is placed on the body surface (for example, the back) 33M of the subject, and in this state, the second signal processing system 5 and the signal conversion system 9 are controlled. The ultrasonic transducer 2 of No. 2 is driven to display a tomographic image of the subject on the screen of the display means 10.

When the kidney image 34 is depicted in this tomographic image, the kidney stone image 35 therein is searched for.

In this case, on the display means 10, based on the signal sent from the CPU 6 to the signal conversion system 9, a fan-shaped sound field area 31 as shown in FIG. 3, a body surface image 33 of the subject, a kidney image 34, Position 36 of first ultrasound transducer 1 such as kidney stone image 35, sound field area 3
7. The focal point markers 38 and the like are displayed at fixed positions, and the displayed part of the tomographic image of the subject displayed in real time changes as the applicator 3 moves.

Then, at the stage when the kidney stone image 35 is depicted in the tomographic image, the applicator 3 is further finely adjusted so that the kidney stone image 35 is located within the focal point marker 38, and in this state, the applicator 3 is to be fixed.

Next, the operator presses the first push button of the pulse generation switch 13 to send a control signal to the pulser 24 via the CPU 6 and controller 7. As a result, a large amplitude pulse signal is sent from the pulser 24 to the first ultrasonic transducer 1, and the first ultrasonic transducer 1 sends an ultrasonic pulse with strong energy to the focal point marker 38. Waves are transmitted toward the kidney stone 35M of the subject located at the corresponding position.

This ultrasonic pulse becomes a shock wave at the position of the kidney stone 35M, and crushes the kidney stone 35M.

By repeating the generation of such ultrasonic pulses as many times as necessary, the entire kidney stone 35M can be crushed.

Note that since the subject is slightly moving due to heartbeat, breathing, etc., the subject signal detection element 12 is
in contact with the subject's hands, feet, chest, or nose,
The subject signal obtained from this subject signal detection element 12 and the signal from the pulse switch 13 are
It is more effective if the CPU 6 synchronizes and controls the timing at which the pulse signal is sent from the pulser 24.

The operation of the apparatus of the above embodiment is based on the premise that the focal point position of the ultrasonic pulse by the first ultrasonic transducer 1 and the focal point marker 38 on the display means 10 correspond without error. However, in reality, these do not necessarily correspond completely. That is, even if the kidney stone image 35 is placed within the focus point marker 38 on the display means 10, the true focus point by the first ultrasonic transducer 1 does not match the position of the kidney stone 35M within the subject. Cases also occur.

This is because when displaying a tomographic image in real time from an echo signal based on sector scanning by the second ultrasound transducer 2, the ultrasound propagation velocity within the subject is set to a constant value (for example, 1530m) in the signal conversion system 9. /s), converting this propagation velocity into a distance, converting the output signal from the second signal processing system 5, and displaying the result on the display means 10. That is, if the actual ultrasonic propagation velocity of the subject differs from the above-mentioned set value, the actual position of the kidney stone 35M will not be correctly displayed on the display means 10.

To explain with a specific example, if the speed of sound when the ultrasound pulse reaches the kidney stone 35M from the body surface 33 of the subject is faster than the above-mentioned setting value of 1530 (m/s), the reflected echo will also return quickly. Therefore, the kidney stone image 35 is displayed on the display means 10 in a positional relationship closer to the actual position.

Furthermore, due to the effects of refraction of ultrasonic pulses,
The error in the display position of the kidney stone image 35 becomes larger. Therefore, the operation for crushing the kidney stone 35M while confirming the true position of the kidney stone 35M in the apparatus of this embodiment will be described below.

First, the operator adjusts the position of the applicator 3 so that the kidney stone image 35 falls within the focal point marker 38, as in the case described above.

Next, the operator presses the second push button of the pulse generation switch 13 to send a signal to the CPU 6 to generate a weak pulse. Based on this signal, the controller 7 is controlled by the CPU 6 and sends a control signal to the pulser 24. As a result, the pulser 24 sends a small amplitude pulse signal to the first ultrasonic transducer 1, and the first ultrasonic wave Transducer 1
A very weak harmonic pulse is transmitted from the probe toward the subject.

This weak ultrasonic pulse hits various tissues of the subject and is reflected, becoming an ultrasonic echo, which is received by the first ultrasonic transducer 1 and exchanged into an echo signal. The receiving circuit 25 receives this echo signal and sends it to the first signal processing circuit 26. The first signal processing circuit 26 is controlled by the CPU 6, detects only the echo signal near the focal point from among the input echo signals, converts it into an audio signal of an audible frequency, and sends it out. The stone position confirmation means 11 generates an audible sound based on this acoustic signal.

While listening to this audible sound, the operator moves the applicator 3 so that the kidney stone image 35 is located within or around the focal point marker 38, and searches for the position where the audible sound is maximum.

With this operation, when the audible sound reaches the maximum because the acoustic impedance of the kidney stone is larger than that of other tissues, the true focus position of the ultrasonic pulse by the first harmonic transducer 1 and the kidney stone 35M are determined.
This means that the position of .

In this state, the operator must turn the pulse generation switch 1
3, press the first pushbutton to send a large amplitude pulse signal from the pulser 24 to the first button as in the case described above.
The ultrasound transducer 1 sends the ultrasound to the ultrasound transducer 1 to crush the renal stone 35M located at the focal point. By the above-described operation, the renal stone 35M in the renal body of the subject can be reliably crushed.

Next, the operation of crushing the kidney stone 35M by combining the stone position confirmation means 11 described above and the change in the scale factor of the tomographic image on the display means 10 in the apparatus of this embodiment will be described.

The tomographic image on the display means 10 can be enlarged or reduced by changing the sound velocity setting value in the signal conversion system 9, that is, the scale factor.

For this purpose, the CPU
6, the sound velocity setting value of the signal conversion system 9 is changed, and when the audible sound from the stone location confirming means 11 is at the maximum, the tomographic image is displayed so that the renal stone image 35 falls within the focal point marker 38 on the display means 10. Set the scale factor for .

Setting the scale factor in this way is more convenient when applying ultrasonic pulses to crush the renal stone 35M of a certain subject many times.

Note that the automatic setting of the scale factor described above is also possible with the apparatus of this embodiment. The method will be explained below.

30 per second by the second ultrasonic transducer 2
Considering the case of obtaining a tomographic image of a frame, a weak ultrasonic pulse is transmitted from the first ultrasonic transducer 1 at each turn of each frame. In this way, the first ultrasonic transducer 1 can transmit 30 ultrasonic pulses per second without affecting the real-time tomographic image produced by the second ultrasonic transducer 2. be able to.

Pulse a ₀ in FIG. 4a indicates a pulse transmitted from the first ultrasonic transducer 1, and pulses a ₁ to a ₅ in FIG.
2 shows a detected waveform of an echo signal received by the first ultrasonic transducer 1 based on a reflected echo from the ultrasonic transducer 1. As is clear from figure a, kidney stone 3
When 5M is located closer to the body surface 33 than the focal point of the first ultrasonic transducer 1, the pulse
A wide pulse a ₁ with small amplitude is obtained in a short time from the firing time of a ₀ .

When the first ultrasonic transducer 1 of the applicator 3 is moved a little away from the body surface 33 and the renal stone 35M is brought closer to the focal point, the pulse a ₁ is slower than the pulse a 1 described above, and has a larger amplitude and width. A narrow pulse a ₂ is obtained.

Furthermore, the first ultrasonic transducer 1 is placed on the body surface 3.
When the position of the kidney stone 35M coincides with the position of the focal point, a pulse _a3 having the maximum amplitude and the narrowest width is obtained, such as pulse _a3 .

The first ultrasonic transducer 1 is further inserted into the body surface 3.
3, the position of the kidney stone 35M becomes further away from the focal point position, and pulses like pulses a ₄ and a ₅ are obtained.

In this case, if the applicator 3 is moved continuously, pulses based on 30 reflected echoes will be obtained per second, and if the envelope of each pulse is drawn, it will be as shown in FIG. 4b. The time T from the emission time of pulse a ₀ to the peak point of this envelope is defined as the time T from the emission time of pulse a 0 to the peak point of this envelope when the focal point of the first ultrasonic transducer 1 coincides with the position of the kidney stone 35M. This corresponds to the time it takes for an ultrasound pulse emitted from the kidney stone 35M to be reflected and received by the first ultrasound transistor 1.

That is, if the radius of curvature of the concave transducer 15 is R, then the time required for the ultrasonic wave to propagate over the distance 2R is T.

Here, since the radius of curvature R is predetermined by the geometrical shape of the concave transducer 15, once the time T is determined, the object is kidney stone 3
The average sound speed C _M up to 5M can be expressed by the following formula.

C _M =2R/T (1) The procedure for determining the sound speed C _M will be explained below.
As mentioned above, the amplitude and width of the reflected echo from a kidney stone is larger and narrower as it approaches the focal point, so the waveforms of each pulse a ₁ to a ₅ shown in Figure 4 a
First signal processing circuit 2 controlled by CPU 6
If a differential waveform signal such as that shown in FIG. 4c is differentiated by 6 and used, the position of the focal point can be more clearly determined. Incidentally, FIG. 4d shows the differential waveform signal envelope shown in FIG. 4c. Such a reflected signal or its differential waveform signal is further subjected to A/D conversion processing, storage processing in a memory, and peak point detection processing using a digital circuit in the first signal processing circuit 26 to automatically detect the time T.

Then, the data of the detected time T is temporarily stored in a memory, this data and the value of the radius of curvature R are taken in, and the calculation based on the equation (1) is performed by a calculation means (not shown) to obtain the average sound speed C _M. this
By sending the sonic velocity setting value to the signal conversion system 9 via the CPU 6, the kidney stone image 35 of the subject can be displayed without error on the display means 10, thereby ensuring that the kidney stone 35M is crushed. becomes possible.

Of course, it is also possible to crush the renal stone 35M by using such automatic setting of the scale factor and acoustic confirmation of the focal point position by the bonding position confirmation means 11.

Note that, in actual diagnosis, there may be non-uniformity of the tissue of the subject, attenuation of the ultrasonic pulse, etc., so some correction may be made to the above equation (1).

Furthermore, since the focal point position may be slightly shifted from the geometric center of the concave vibrator 15,
It is also possible to control the signal conversion system 9 by the CPU 6 so that the sound field region 37 and the focal point marker 38 produced by the first ultrasonic transducer 1 are displayed slightly asymmetrically.

Further, the sound generated by the calculus position confirmation means 11 may be made proportional to the amplitude of the reflected echo, or may be an intermittent sound such that the larger the reflected echo, the narrower the interval.

Furthermore, in addition to using a speaker as the calculus position confirmation means 11, earphones may be used in consideration of the influence on the subject.

Furthermore, according to the present invention, when checking the coincidence between the converging point of the crushing wave and the stone, the first
Since this is performed by transmitting and receiving weak ultrasonic waves using the relatively large-area concave transducer 15 of the ultrasonic transducer 1, there are no minute obstacles such as bones or fat on the ultrasonic propagation path. In this case, these obstacles can be correctly recognized under the same conditions as during crushing, and no problems will occur when destroying the stone.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention.

For example, in the above-described embodiment, the case where the kidney stone position is confirmed acoustically is explained, but the present invention is not limited to this, and the display means 10 displays an echo signal as shown in FIG. 4 obtained by the first signal processing circuit 26. The generation timing of the pulse signal for crushing can be determined by checking the magnitude of the amplitude.

In addition, although the above-described embodiment apparatus has been described for crushing kidney stones, the present invention is not limited to this and can be applied to crushing gallstones, etc.

[Effects of the Invention] According to the invention described in detail above, it is possible to reliably and repeatedly crush a stone in a subject without being exposed to any radiation such as X-rays.

Further, it is possible to provide an ultrasonic stone crushing device that does not require a water tank or the like to house a subject, and the entire device can be made smaller and lower in price.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a device according to an embodiment of the present invention, Fig. 2 is a schematic explanatory diagram showing the configuration of an applicator in the same device and its sound field region, and Fig. 3 is a display state on the display means in the same device. FIG. 4a is a waveform diagram showing the state of transmission and reception of ultrasonic pulses in the first ultrasonic transducer of the device, and FIG. 4b is an envelope of the waveform shown in FIG. 4a. FIG. 4c is a waveform diagram showing the differential waveform of the received pulse shown in FIG. 4a, and FIG. 4d is a waveform diagram showing the differential waveform of the received pulse shown in FIG.
FIG. 3 is an explanatory diagram showing a waveform envelope showing the waveform shown in FIG. 1... first ultrasonic transducer, 2...
Second ultrasonic transducer, 3... Applicator, 4... First signal processing system, 5... Second signal processing system, 8... Control system, 9... Signal conversion system, 1
0... Display means, 11... Stone position confirmation means, 1
2... Subject signal detection element, 13... Pulse generation switch, 14... Sound speed setting means, 33M... Body surface, 35... Kidney stone image, 35M... Kidney stone.

Claims (1)

[Claims] 1 a first ultrasonic transducer having a concave shape and forming an ultrasonic focal point at its geometric center; a second ultrasonic transducer that forms a sound field region including the focal point to obtain tomographic image data of the subject; and a focal point marker corresponding to the focal point in a tomographic image based on the tomographic image data; and display position determination for detecting a reflected echo signal of the ultrasound emitted from the first ultrasound transducer due to the stone and determining the display position of the focal point marker based on the information. An ultrasonic stone crushing device characterized by comprising means.