JPH0315456A - Shock wave radiator of out-body type shock wave calculus crushing machine - Google Patents

Abstract

PURPOSE:To improve efficiency of crushing a calculus with energy effectively used so as to prevent an unnecessary pain from being given to a patient by providing a subreflecting means which is arranged in an opposite side to a reflecting means with respect to a point-shaped sound source to reflect a shock wave toward the reflecting means. CONSTITUTION:A shock wave, generated in a point sound source 1 placed in the focus of a main reflector 7, is reflected by the main reflector 7, propagated in a transmission medium 9 as a focus shock wave 4 and focused to a calculus 10, and it is crushed. Out of the shock waves radiated from the point sound source 1, non-focused shock waves 6, radiated to the front and not reflected by the main reflector 7, are placed in the vicinity of a focus position, and the waves 6 are reflected by a subreflector 8, which covers an opening angle of the main reflector 7, to reach the main reflector 7 and reflected by the main reflector 7 to focus on the calculus 10.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a shock wave radiator for an extracorporeal shock wave stone crushing frame machine that uses ultrasonic shock waves to crush stones from outside the body, and particularly to This invention relates to a shock wave radiator for an improved extracorporeal shock wave lithotripter.

(Prior art) Regarding stones that occur in organs, stones are not formed in a short period of time, but substances gradually deposit on the walls of the lumen of the bladder, gallbladder, blood vessels, etc., and this grows and forms stones. It is a disease that is first discovered when the membrane peels off from the wall and flows with the fluid flowing in various parts, gets stuck in narrow parts such as the urethra, bile ducts, or blood vessels, and obstructs the passage of fluids such as urine, bile, and blood, causing severe pain. be. Removing this stone poses biosafety issues and requires a large amount of money, so it would be best if the stone could be crushed externally without surgery while it is still small. As a means of this, E
SW. A device called L (extracorporeal shock wave lithotripter) is used.

(Problems to be Solved by the Invention) Conventionally, in the above-mentioned ESWL, shock waves are radiated by a shock wave radiator as shown in FIG.

In the figure, 1 is a point sound source that emits ultrasonic waves, and 2 is an ellipse that places the point sound source 1 at one focal position and focuses the radiated shock wave from the point sound source 1 to a focal point 3 that is the other focal position. It is a reflector. 4 is a focused shock wave reflected by an elliptical reflector 2 and focused on a focal point 3; 5 is a point sound source 1;
It is a direct wave that is emitted forward from the elliptical reflector 2 and is scattered in a space other than the focusing point 3, and exists within the range of the non-focused shock wave 6.

In this way, the direct wave 5 that is not reflected by the elliptical reflector 2 is the fifth wave.
As shown in the figure, since the pressure is low and does not contribute to stone fragmentation, some of the energy manually applied to the shock wave emitter is not used, resulting in either wasted energy or unnecessary pain to the patient. was.

In the case of the spheroidal reflector shown in FIG. 6, this energy loss is as shown below. In the figure, consider a spheroidal reflector whose major axis is a and whose minor axis is b, and which is cut by a plane including the Y axis perpendicular to the X axis. Let R be the distance from the focal point to the circumference of the aperture surface, and h be the distance between the aperture and the intersection with the X-axis of a spherical surface with the focal point center and R as the radius.

If the energy loss of the reflector as described above is the ratio of the total area FA of the spherical wave with the focal point as the center and radius R to the area Fl1 of the spherical wave of the part corresponding to the direct wave, the energy loss S is as follows. It is determined by the formula.

... (1) Here, from the ellipse equation, for the reflector shown in the figure where the short axis b of the ellipse is the aperture radius, R = a, h = a - fT1-17, so from equation (1), the energy The loss S is expressed as follows.

4 3 From the formula =0.09 That is, the energy loss is 9%.

The present invention has been made in view of the above points, and its purpose is to effectively use the ultrasonic energy emitted from the shock wave radiator of ESWL to increase stone fragmentation efficiency and avoid causing unnecessary pain to patients. The goal is to realize an E SWL shock wave radiator.

(Means for Solving the Problems) The present invention that solves the above problems includes a point-like sound source that generates an ultrasonic shock wave, and a point-like sound source that is placed at a focal position to reflect the shock wave from the point-like sound source. In the shock wave release device of an external shock wave lithotripter having a reflection means, a sub-reaction body and one means are arranged on the reflection side of the reflection means with respect to the point sound source and reflect the shock wave toward the reflection means. It is characterized by comprising:

5 (Function) Shock waves emitted from a point sound source toward the reflecting means are reflected by the reflecting means and focused on the stone, and shock waves emitted in the opposite direction of the reflecting means are reflected by the sub-reflecting means. It is reflected towards the means and focused onto the stone by said reflecting means.

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

FIG. 1 is a schematic structural diagram of a shock wave radiator according to an embodiment of the present invention. In the figure, parts equivalent to those in FIG. 4 are given the same reference numerals. In the figure, 7 is a point sound source 1 located at the focal position
The main reflector has an ellipsoidal shape that reflects the shock waves emitted from the main reflector. A sub-reflector 8 is installed near the point sound source 1 and has an area covering the aperture angle of the main reflector, and reflects shock waves that are not reflected by the main reflector 7 and irradiates them onto the surface of the main reflector 7. Each shock wave reflected by the main reflector 7 propagates through the transmission medium 9 and is focused on the calculus 10. 16 1 shows the patient's body surface.

Next, the operation of the embodiment configured as described in section 2 will be explained. The shock wave generated by the point sound source 1 placed at the focal point of the main reflector 7 is reflected by the main reflector 7, propagates through the transmission medium 9 as a focused shock wave 4, and is focused on the calculus 10, thereby crushing the calculus 10. Among the shock waves emitted from the point sound source 1, the unfocused shock waves 6 that are emitted forward and are not reflected by the main reflector 7 are near the focal point and are reflected by the sub-reflector 8 that covers the aperture angle of the main reflector 7. The light reaches the main reflector 7, is reflected by the main reflector 7, and is focused on the calculus 10.

FIG. 2 is a diagram showing the sound pressure distribution of the shock wave with respect to the time axis according to the example. In the figure, 21 is the sound pressure of the shock wave focused on the stone 10 by the main reflector 7, and 22 is the sound pressure of the shock wave reflected by the sub-reflector 8, reflected again by the main reflector 2, and focused on the stone 10. In the figure, unlike the conventional case shown in Fig. 5, there is almost no time difference between the shock waves coming off the main reflector 2
This shows a state in which the sound pressure is focused on the stone 10 with a larger sound pressure than a conventional non-focused wave. Furthermore, by installing the sub-reflector 8 sufficiently close to the point sound source 1, the focused shock wave 22 from the sub-reflector 8 approaches the focused shock wave 21 from the main reflector 7, and can form one pressure waveform. .

As explained above, according to this embodiment, the shock wave that is not directly reflected by the main reflector 7 is also reflected by the main reflector 7 via the sub-reflector 8, and is focused on the calculus 10. It can participate in the fragmentation, increasing the stone fragmentation efficiency and eliminating waste of radiant energy.

Furthermore, unnecessary shock waves can be eliminated, thereby eliminating unnecessary pain to the patient.

Note that the present invention is not limited to the above embodiments.

FIG. 3 is a schematic structural diagram of another embodiment of the present invention. In the figure, parts equivalent to those in FIG. 1 are given the same reference numerals. In the figure,] 2 refracts the ultrasonic shock wave to form a stone 10.
It is an acoustic lens that acts as a self-lens to focus the sound.

The operation of this embodiment will be explained. The shock wave radiated from the point sound source 1 placed at the focal position is reflected by the main reflector 7 which forms a parallax, becomes a parallel wave, and is incident on the acoustic lens 12. 10 to crush the stone 10. The shock wave radiated in the direction of the sub-reflector 8 placed at the approximate focal point is reflected by the sub-reflector 8 in the direction of the main reflector 7, is converted into a parallel wave by the main reflector 7, and is then turned into a parallel wave by the acoustic lens 12. Stones 1 focused on 10
Participate in o's break.

(Effects of the Invention) As described above in detail, according to the present invention, the ultrasonic energy radiated from the ESWL can be used without waste to improve the stone crushing efficiency, and furthermore, unnecessary pain can be avoided for the patient. This eliminates the need to feed, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram of sound pressure distribution of the embodiment, FIG. 3 is a schematic structural diagram of another embodiment of the present invention, and FIG. 4 is a conventional diagram. A schematic structural diagram of the ESWL shock wave radiator, Figure 5 is a diagram of the sound pressure distribution of shock waves by a conventional shock wave radiator, and Figure 6 is an explanatory diagram for calculating radiant energy loss when there is no sub-reflector. It is. 1... Point sound source 4... Focused shock wave 6...
・Unfocused shock wave 7...Main reflector 8...Sub-reflector 10 Calculus 12...Acoustic lens

Claims (1)

[Claims] In a shock wave radiator of an external shock wave lithotripter, the shock wave radiator of an extracorporeal shock wave lithotripter has a point-like sound source that generates an ultrasonic shock wave, and a reflecting means that places the point-like sound source at a focal position and reflects the shock wave from the point-like sound source. A shock wave radiator for an extracorporeal shock wave lithotripter, comprising a sub-reflection means that is disposed on the reflection side of the reflection means with respect to a shaped sound source and reflects a shock wave toward the reflection means.