JPH0554987B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an extracorporeal shock wave lithotripter that uses ultrasonic shock waves to crush stones from outside the body. The present invention relates to an extracorporeal shock wave lithotripter used in combination with an ultrasonic return transmission method orthography device.

(Prior art) Regarding stones that occur in organs, stones do not form overnight; substances gradually deposit on the walls of lumens such as the bladder, gallbladder, or blood vessels, and these stones grow and grow. The formed stones break off from the wall, flow with the fluid flowing in various parts, and get stuck in narrow parts such as the urethra, bile ducts, or blood vessels, causing urine,
This is a phenomenon that is only discovered when it obstructs the permeation of fluids such as bile and blood, causing severe pain. Since the removal of this stone poses biosafety issues and requires a large amount of money, it goes without saying that it is preferable to remove the stone before it becomes stuck in a small and narrow area. Therefore, it is best to detect and treat stones when they are small, before they develop.

On the other hand, in medical terms, ultrasound systems irradiate ultrasound waves into the subject's body, and observe and diagnose tissues and lesions using the echo signals that are reflected back from various tissues and lesions within the subject's body. Although it is a device, recently,
Utilizing the large energy of elastic waves called ultrasound,
Applications have been developed in anticipation of changes such as irreversible and specific destruction of tissues. One of them is an external shock wave lithotripter (External shock wave lithotripter).
Shock Wave Lithotripter (hereinafter referred to as ESWL)
There is. This uses relatively low-frequency ultrasound and uses various ultrasound focusing techniques to focus the ultrasound into a sharp point, and in this focal region, the intensity of the sound is hundreds of times higher than the intensity of the emitted ultrasound. This is a device that generates stones that break up stones that have formed inside organs. When the beam is focused and irradiated in this way, localized destruction nests are generated only at the position corresponding to the focal point.
It has been found that the tissues intervening between the surface layer of the subject and the focal point are not affected at all.

(Problems to be Solved by the Invention) In order to determine the correct focal position in this way, it is necessary to perform aiming imaging to determine the position of the stone in relation to organs and the like. As imaging means for this aiming, there are two methods used in the past, such as X-ray stereoscopic vision and newer ultrasound B-mode ecography imagers, which are divided into two methods in the medical world. In short, it was simply a combination of the imager and the shock wave emitting side placed side by side to facilitate aiming. There is a need for ESWL that organically combines the two and can be used to detect small stones before they develop into stones.

The present invention has been made in view of the above points, and its object is to organically combine an imaging means for aiming that can easily detect even small stones, and a powerful pulse shock wave generation means. ESWL
The aim is to realize this.

(Means for Solving the Problems) The present invention, which solves the above-mentioned problems, has a plurality of elements, and when transmitting waves, the waves are transmitted non-focally in a range that covers the required angle of view, and are reflected behind the target area and returned to the target. An imaging array consisting of a two-dimensional array transducer that focuses and receives signals passing through an area on the target area, and an ultrasonic wave that aims at the target area by reconstructing the image from the data received by the imaging array. A means for creating a return transmission method orthography, a means for generating a shock wave transmission pulse for transmitting a shock wave with a long repetition period to break up a stone, and an imaging means for transmitting a shock wave pulse by focusing an ultrasonic pulse on a target area. The apparatus is characterized by comprising an ultrasonic wave transmitting means consisting of an array of shock wave transmitting transducer elements provided around the array. Further, if the reflected wave of the shock wave transmission pulse is used as a transmission signal for position confirmation, curing will be further improved.

(Function) The transmitted ultrasonic pulse is reflected, transmitted through the object, and returned as an image by the return transmission method orthography creation means to determine the aim, and the shock wave transmission pulse generation means The pulses generated are transmitted by a shock wave transmission transducer element array to crush the stone. When there are two or more stones, from the second time onwards, aiming can be carried out efficiently by using the reflected wave from the shock wave as an echo signal in the return transmission method.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of an ultrasonic probe used in an apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram of an aiming imager using ultrasonic return transmission method orthography according to an embodiment of the present invention. It is a diagram. In Fig. 1, reference numeral 1 denotes an ultrasonic probe used in this device to transmit and receive ultrasonic waves, an imaging array 2 for locating and aiming at the stone, and a shock wave array placed around it. It is composed of a generation piezoelectric element 3. The shock wave generating piezoelectric elements 3 are arranged so as to focus the transmitted ultrasonic waves at a focal position, and are respectively connected to power drivers (not shown) of the transmitter. Reference numeral 4 denotes a sound-transmitting membrane that covers these ultrasonic probes and contains a liquid therein to form a liquid chamber 5 in order to acoustically couple the transducer element and the living body. A protector 6 surrounds the imaging array 2 and prevents it from being damaged by high energy shock waves from the shock wave generating piezoelectric element 3. An imaging probe 7 consisting of an imaging array 2 and a protector 6 passes through the center of a shock wave generation probe 8 to which a shock wave generation piezoelectric element 3 is attached and is connected to an aiming imager. .

FIG. 2 is a block diagram showing only the receiving section of the imager for transmitting and receiving ultrasonic waves by the imaging probe 7 and aiming the shock waves at the stone to be irradiated. Since the transmitter transmits waves simultaneously from all elements of the imaging array 2 and is no different from a normal device, FIG. 2 shows only the receiver for one channel. In the figure, the first
Parts equivalent to those in the figure are given the same reference numerals. 1
1 is an amplifier for amplifying the signal received by the imaging array 2; 12 is a range gate for extracting only the data in the target area; the output data is coherently detected by the detector 13, and is combined with the i signal of the in-phase signal. Outputs the q signal of the orthogonal signal. 14
stores a RAM 15 that stores complex holograms, a digital signal processor (hereinafter referred to as DSP) 16 that performs Fourier transform operations, and software such as instructions related to the arithmetic processing of DSP 16.
Store PROM17 and calculation result data
This is an image reconstruction calculation device consisting of RAM18.
19 is a digital scan converter (hereinafter referred to as
DSC) to display the converted data on the TV 20.

Prior to explaining the operation of the device configured as described above, the principle and features of this aiming imager will be explained.

As explained earlier, ESWL in this example detects stones that are developing before they develop into stones, so ultrasound is radiated into the subject's body as usual and the reflected waves are With the observation method, it is extremely difficult to detect small stones because there are too many targets that reflect ultrasonic waves, but with the transmission method, it is possible to find stones with a small transmittance compared to the surrounding tissue. The transmission method is used because it is easy.

In the transmission method, it is necessary to transmit waves from the other side of the target object, but the equipment is large-scale, so the return path transmission method as shown below is adopted. The principle diagram of the return passage method is shown in Figure 3.

In the figure, 21 transmits long pulses all at once with no focus at an illumination angle that roughly covers the entire desired angle of view (solid angle) when transmitting waves, and focuses on target area 2 when receiving waves. It is a two-dimensional array transducer that scans and receives waves, and a somewhat long space 23 is provided in order to obtain an orthogonal projection image. Reference numeral 24 denotes an echo generating section for reflecting the transmitted ultrasonic waves from the two-dimensional array transducer 21 located behind the target area 22, and the reflected waves from the echo generating section 24 are blurred so as not to create a clear image. Something that looks like that is desirable.

Next, a method of creating an orthogonal projection image obtained by ultrasonic waves transmitted and received in the arrangement as described above will be explained. For example, from 30 to 2MHz at 2MHz so as to cover the entire field of view from the two-dimensional array transducer 21.
A long pulse of approximately 50 μs is transmitted toward the target area 22. The transmitted ultrasonic wave passes through the target area 22, is reflected by the echo generator 4, passes through the target area 22 again, and reaches the two-dimensional array transducer 21. The space 23 is set at a relatively long distance because there is a limit to the angle of view for creating an orthogonal projection image. At the point when the reflected wave returns from the echo generator 24, the two-dimensional array transducer 2
1, find the hologram. Since the pulse width is long, it can be considered as a CW mode, and the received data becomes one piece of complex data for each element of the two-dimensional array transducer 21. Specifically, the echo from the echo generator 24 passes through the target area 22 and returns to the two-dimensional array transducer 21 in a time period that matches the interval width and sending timing of the transmitted long pulse. , Coherent detection of data is performed for each element, the data separated into in-phase components and quadrature components are separately integrated to obtain complex reception data of the element, and data of all elements are collected to form a complex hologram.
This data is stored in the computer's memory.

Based on this two-dimensional hologram, the propagation length to the target region 22 is determined by Fresnel approximation method or Kirchhoff's exact solution method, specifying the relevant aperture internal partial region each time if necessary, and the propagation term is calculated. The complex data of the target area 22 is obtained by solving the wavefront backpropagation algorithm. This part of the calculation is basically an inverse Fresnel transform, and can be implemented by adding a phase correction term to the inverse Fourier transform, as is known.

The apparatus of this embodiment uses the return path transmission method as described above. Returning to FIG. 2, the operation will be explained.

Reflected wave signals received based on the transmitted wave signals emitted all at once from the imaging array 2 are amplified by the amplifier 11 . The range gate 12 passes data in a time period corresponding to the distance from the time of transmission at the time when the wave is reflected by the echo generator 24 and transmitted through the target area 22 . The position of this range gate 12 can be changed, and the observation area can be changed sequentially to search for stones. The data that has passed through the range gate 12 is coherently detected in the detector 13 and outputs a complex signal separated into an i signal and a q signal, which is input to an image reconstruction device 14, and is first
Stored in RAM15. The data stored in the RAM 15 is a complex hologram of all elements. This two-dimensional hologram is subjected to the image reconstruction calculation described in the above method by the DSP 16 based on the instructions from the PROM 17, and the resulting data is
Stored in RAM18. The data stored in the RAM 18 is read out sequentially, and the DSC 19
It is converted into TV image data and displayed on the TV 20.

A return transmission method osthography device as described above provided with a phase conjugate or refraction correction algorithm is used as the receiving section. The receiving section of this return transmission method orthography apparatus is connected to the imaging array 2 of the ultrasound probe 1 shown in FIG. 1 together with the transmitting section. A target area 22 is set by transmitting and receiving waves from the imaging array 2, and a pulse wave having a high power peak value with a long repetition period is focused from the shock wave generating piezoelectric element 3 and applied to the developing stone. crush. The shock wave generator is essentially the same as a normal device other than transmitting ultrasonic pulses with a longer repetition period and a larger peak value of the pulse wave, so a description thereof will be omitted. The protector 6 protects the imaging array 2 from the impact of the waves of the high power pulses. The liquid chamber 5 optimizes the acoustic coupling between the subject and each transducer element of the ultrasonic probe, and forms the space 23 shown in FIG. 3.

As explained above, according to this embodiment, the return transmission method orthography device and the ESWL are coupled via the ultrasound probe 1, so that the imaging array can be detected using the conventional echo method. Even small stones and soft stones can be reliably found in clear condition and removed.

Note that the present invention is not limited to the above embodiments. In the embodiment, the return transmission method orthography device transmitted waves by itself and received the echoes from the echo generator 24, but when there are two or more stones, the ESWL is used for the second and subsequent stone crushing.
It is also possible to use an echo obtained by reflecting a shock wave from the echo generating section 24.

(Effects of the Invention) As explained in detail above, according to the present invention, it becomes possible to reliably discover small developing stones in a clear state and crush them, which improves biosafety and cost efficiency. A highly useful device can be realized, and the practical effects are great. Furthermore, efficiency can be further improved by using the shock wave for stone fragmentation in place of the transmission signal of the return transmission method.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an ultrasonic probe according to an embodiment of the present invention, FIG. 2 is a block diagram of an embodiment of a receiving section of a return transmission method orthography apparatus used in the present invention, and FIG. FIG. 2 is an explanatory diagram of a method of return transmission orthography. 1... Ultrasonic probe, 2... Imaging array, 3... Piezoelectric element for shock wave generation, 4...
...Sound-transmitting membrane, 5...Liquid chamber, 6...Protector, 7...
... Imaging probe, 8... Shock wave generation probe, 12... Range gate, 13... Detector,
14... Image reconstruction calculation device, 15, 18...
RAM, 16...DSP, 17...PROM, 19...
...DSC, 21...Two-dimensional array transducer, 22...Target area, 23...Space, 24...
Echo generating part.

Claims (1)

[Claims] 1. Having a plurality of elements, when transmitting waves, the waves are transmitted non-focally to a range that covers the required angle of view, and the signal that is reflected behind the target area and passes through the target area again is focused on the target area. an imaging array consisting of a two-dimensional array transducer that receives waves from the imaging array, an ultrasonic return transmission method orthography creation means that aims at the target area by reconstructing the image of the wave data received by the imaging array, and a stone fragmentation method. Shock wave transmission pulse generating means for transmitting shock waves with a long repetition period for the purpose of the imaging, and Shock wave transmission vibration provided around the imaging array for converging the ultrasonic pulses on the target area and transmitting the shock wave pulses. 1. An extracorporeal shock wave lithotripter comprising an ultrasonic wave transmitting means comprising a sub-element array. 2. An imaging array composed of a two-dimensional array transducer that receives a signal from which the shock pulse transmitted from the ultrasonic wave transmitting means is reflected behind the target area and passes through the target area again, focusing on the target area. Claim 1 characterized in that it has
The described extracorporeal shock wave lithotripter. 3. The extracorporeal device according to claim 1 or 2, further comprising a protection means arranged around the plurality of elements of the imaging array to protect the imaging array from directly receiving shock wave pulses from the ultrasound transmitting means. Shock wave lithotripter.