CZ2020214A3 - Equipment for generating high local intensity ultrasound - Google Patents

Abstract

The subject of the technical solution is a device for generating ultrasound of high local intensity formed by a chamber (2) and an outer shell (17) defining a cavity (7). The inner surface (8) of the outer shell (17) has the shape of a rotating paraboloid and the cavity (7) of the outer shell (17) is adapted to contain a liquid medium (3). The outer casing (17) is connected by means of a threaded connection to the chamber (2), in which a piezoelectric transducer (1) is arranged, placed between the first "O" ring (4) and the second "O" ring (5), on which the cover nuts abut. (6) connected by a threaded connection to the chamber (2). A matching acoustic plate (16) is further arranged between the cavity (7) and the piezoelectric transducer (1). The outer shell (17) is terminated at the apex by an opening (10) which is provided with a nut (11) with an annular recess in which resilient circular washers (12) securing the membrane (13) are arranged.

Description

Equipment for generating ultrasound of high local intensity

Field of technology

The present invention relates to a device for generating ultrasound of high local intensity using wave reflections on the inner surface of a rotating paraboloid.

Prior art

Ultrasound energy is widely used in physical medicine, in therapy, especially when we want to transfer the energy of ultrasonic waves to living tissues in order to achieve mechanical effects ("internal pressure micromassage", loosening of structures, gel-to-sol conversion, thixotropic effects, dispersion effects), thermal (heating), chemical (support of biochemical reactions) and biological (increase of semipermeability of cell membranes, stimulation of sympathetic, polymerization and depolymerization and others). As a result of the connection of all the above factors, it can be argued that ultrasound has an analgesic effect, increases blood flow to tissues, reduces muscle tension, increases connective tissue expansion (scars, conditions after muscle and joint capsule injuries), accelerates wound healing, etc.

Chinese Utility Model CN 201716410 U discloses an ultrasonic radiation focusing apparatus comprising an ultrasonic generator arranged in a focusing cavity in the shape of a rotating paraboloid with a reflective surface. The ultrasound generator is a source of direct ripple propagating in the x-axis toward the base of the focusing cavity and a reflected ripple propagating first to the reflective surface, and then substantially parallel to the x-axis toward the base of the focusing cavity. For constructive wave interference, it is necessary to satisfy certain geometric relationships given by the shape of the rotating paraboloid and the wavelength.

The technical problem addressed by this utility model is to provide an ultrasonic focusing device with better directivity and range of propagation of the ultrasonic beam through free space, most often air, as the disadvantage of the prior art in this case is that the ultrasonic wave beam generated by the ultrasonic generator (ultrasonic transducer) is divergent, divergent and reaches only short distances in the transmission of waves.

Chinese patent application CN 105214222 A discloses a device for applying ultrasound in dual mode in physiotherapy, comprising a head generating mechanical ultrasound and a plate generating "electromagnetic" ultrasound arranged below the head, the head being arranged inside a cylindrical outer housing further provided with associated electronics . Dual mode in the context of this solution means the use of two therapeutic physical interactions - mechanical and electromagnetic ultrasound.

The head is in the form of a double rotating paraboloid formed by a first, convex rotating paraboloid, which is provided at its base with a planar ultrasound generator, such as a piezoelectric transducer, and a cover layer with sound-absorbing properties. the vertex is coaxially connected to the vertex of the first paraboloid so that both rotating paraboloids have a common focus. The second, concave rotating paraboloid has an open base that is directed toward the irradiated surface of the patient's body. In total, two variants of the location of the common focus are described.

In the first variant, the direction of propagation of the ultrasound beams is described, which are partly concentrated in the focus of the double paraboloid and partly emanate from the open base as a parallel, collinear beam. Since the focus is located beyond the base of the second paraboloid, ie directly on or below the irradiated surface of the body, vibrations occur

-1 CZ 2020 - 214 A3 with maximum frequency except outside the double paraboloid. In other words, the beam of rays thus emanates from the double paraboloid partly collinear and partly converging into a focus outside the double paraboloid. In addition, the base of the long paraboloid is not closed by any overlay element, such as a membrane.

In a second variant, the direction of propagation of the ultrasound beams is described, which are partially concentrated in the focus of the double paraboloid and further defocused on the inner surface of the second, concave paraboloid. Since the focus is located in front of the boundary of the base of the deep paraboloid, i.e. within the cavity of the second paraboloid, there is a partial and additional defocus on the inner surface of the deep paraboloid. In other words, the double paraboloid emits a beam beam substantially collinear and without convergence to a single point outside the double paraboloid, thus providing a scattered, dissipated ultrasonic energy that is evenly distributed over the entire circular surface of the base of the damp paraboloid. In addition, the base of the long paraboloid is not closed by any overlay element, such as a membrane. The resulting physical interaction is referred to in the context of this solution as "mechanical" ultrasound.

At the same time, this solution describes a board in the form of a flexible printed circuit board, on which a fixed coil with a printed, spiral winding is arranged and in which an opening for inserting an open base of a damp, concave rotating paraboloid is arranged in the middle. A current is introduced into the coil of this possible printed circuit board, probably at sufficiently high frequencies corresponding to the therapeutic ultrasound (i.e. at least in the order of hundreds of kHz to units of MHz). The plate can be applied tightly to the irradiated surface of the patient's body. The high-frequency magnetic field generated around the coil generates both induced electric currents and heat. However, the induced electric currents are due to the movement of electrically charged particles in tissues which are capable of at least some free movement. However, these particles (mainly sodium, potassium, etc.) do not move anywhere, because the inducing magnetic fields are alternating and high-frequency, so that the electrically charged particles only oscillate in the rhythm of the magnetic field excitation frequency. The resulting physical interaction is referred to as "electromagnetic" ultrasound in the context of this solution.

The technical problem addressed by this patent application is to provide a device for generating a focused ultrasound beam with higher vibration intensity and heat transfer in physiotherapy, since the disadvantage of the prior art in this case is that the current physiotherapy options in the home environment and with sufficient vibration intensity and heat transfer is limited to unfocused interactions in the home environment (eg massages, unfocused ultrasound), or the use of focused ultrasound from related medical disciplines, but with the need for the assistance of professional supervision.

U.S. Pat. No. 6,217,530 B1 discloses a device for the therapeutic application of ultrasound, comprising a piezoelectric concave transducer arranged at the base of a cavity forming a solid-filled space in the shape of a truncated cone, the cavity being of a low acoustic attenuation material, e.g. aluminum. This document also discusses prior art arrangements where a similar cavity is filled with water, but with the disadvantage of more difficult handling and the risk of leakage. The piezoelectric transducer is housed in a chamber and is bounded on the back by a rear cavity and chamber space. The truncated cone cavity is terminated at the apex by an opening, e.g. a spherically concave opening for focusing the outgoing ultrasound, or a spherically convex opening for defocusing the outgoing ultrasound. An adaptation layer of% wavelength width may be provided in the opening to improve the acoustic connection. A waveguide may extend to said opening to extend the focal area, and the waveguide may be connected to the cavity by means of a nut, bayonet or other permanent connection.

It is a general knowledge that the cone as such has no focus in principle. The fact that in this solution the ultrasonic beam is focused towards the top of the cone is not due to the reflection on the walls of the cavity in the shape of a truncated cone, but it is due to the use of a spherical shape ultrasonic generator having a concave frontal radiation surface. The disadvantage of unplanned generators

- 2 EN 2020 - 214 A3 ultrasound is their high cost and low availability. The technical problem addressed by this patent is to provide a non-liquid media refillable device for the application of therapeutic ultrasound, which will allow it to be rapidly sterilized and ready for use.

U.S. Pat. No. 4,484,569 A, which describes an ultrasound diagnostic and therapeutic device and method of using the same, provides a truncated cone focusing head with a concave piezoelectric transducer located in the circular base of the cone, focused on a small circular membrane at the apex of the cone. The resulting cavity is filled with a suitable fluid (water) with a slight overpressure causing convex arching of the membrane, and thus a better transfer of focused ultrasonic energy to the tissues to which the tip of the cone is applied. The diaphragm is attached to the tip of the cone in the stretched state by means of O-rings on the outer casing of the head and forms a point secondary source of ultrasound. The piezoelectric transducer can further be mounted in the head by means of a system of rubber O-rings. The head may further be provided with a spout for the supply and / or discharge of a liquid medium. The described solution can also be used for coagulation of ahemostasis. The patent also mentions the solution of ultrasound focusing using acoustic mirrors, dielectric mirrors, telescopic extensions connected to transducers with a concave radiating surface, the possibility of using phase shifts of waves of several sub-transducers, most often annular shapes, placed concentrically.

As in U.S. Pat. No. 6,217,530 B1, the ultrasonic beam is already focused using the concave surface of the piezoelectric transducer, with the truncated cone head being only a kind of "sheath" necessary for the technical realization of ultrasound beam transfer from transducer to patient body. No reflections and / or focusing occur in the head from this cladding, and there is no focus from the geometric principle of the cone. Thus, the technical problem addressed by this patent is to provide a device for the therapeutic and diagnostic application of ultrasound propagated to the application site in a substantially axial direction.

It can be added to this solution that the use of ultrasonic amplification waveguides (sonoamplifiers, sonicators) in medicine and industry is based on the need to amplify the ultrasonic waves produced by the converter and the introduction of such amplified ultrasonic waves at the application site. For this purpose, cylindrical extensions firmly connected to the transducer are used, the diameter of which decreases so that the end of the waveguide amplifier has a smaller diameter than the waveguide at its contact with the transducer and whose length is equal to or equivalent to the wavelength . Depending on the shaping method, they are divided into exponential, stepped, conical and cylindrical sonoficators. The gain is given by the ratio of the start and end diameters of the waveguide. A special type is the Fourier sonofiator. In English, amplifying ultrasonic waveguides (sonoficators) are usually referred to simply as ultrasonic tubes (untrasound hom).

U.S. Patent Application No. 2014058293 A1 addresses the solution of ultrasound focusing and the achievement of a sufficiently high energy transfer to a desired relatively small locality within the body, where it is necessary to provide thermal and mechanical effects that induce thrombolysis, coagulation or ablation. It uses acoustic mirrors, transducers with concave faces, concentric arrangement of ring transducers, a combination of several frequencies and phase shift. Ultrasonic devices designed with the aim of focusing large energy into a small area or volume, and thus achieving a high volume density of power, are designed primarily for promising use in the removal of tumors.

International patent application WO 2008002773 A2 is directed to the treatment of wounds with ultrasound devices. A funnel-shaped attachment (hemisphere) made of a flexible material is firmly placed on the head with the ultrasonic transducer, which is hermetically applied to the wound and filled with saline or another suitable liquid with medicinal or at least inert effects. Ultrasound propagating through this environment has sufficient intensity to induce borderline cavitation and the chemical (with the help of radicals) and mechanical action of cavitation on the wound surface ensures its debridement and supports its healing.

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The adapter for diagnostic ultrasonic heads for intraoperative applications using a rubber material of suitable acoustic impedance is addressed in U.S. Pat. No. 6,599,249 B1.

Another type of adapter according to U.S. Pat. No. 7,029,446 B2 applies a lamella closed plastic collar to the front of the ultrasonic probe, into the cavity of which a self-adjusting gel insert is inserted.

Another patent relating to a focusable adapter is addressed in U.S. Patent Application No. 2004234453 A1, where a concentrating ultrasonic lens is applied to the active face of an ultrasound generator and the focused ultrasonic wave is guided by a reinforced truncated cone-shaped hydrogel insert (copying the focused ultrasonic beam). conical head with a hole in the top through which the hydrogel cone protrudes and makes contact with the body surface.

As in U.S. Pat. No. 6,217,530 B1, the ultrasound beam is already focused using the concave surface of the ultrasound generator, with the truncated cone head being only a kind of "sheath" necessary for the technical realization of the ultrasound beam transfer from the generator to the patient's body. No reflections and / or focusing occur in the head from this cladding, and there is no focus from the geometric principle of the cone. The technical problem addressed by this patent application is to provide a material suitable for the transmission of ultrasound waves from the source to the site of application (e.g. to achieve hemostasis or surgical ablation) that also meets the requirements of in vivo biocompatibility, sufficient mechanical strength and resistance to ultrasound. high intensity radiation and low acoustic attenuation.

Thus, it is not known from the prior art to provide a device for the application of therapeutic ultrasound suitable for the treatment of surface lesions, especially wounds and skin defects, including their debridement, which would allow ultrasound transmission between generator, liquid transfer medium, membrane and application site with minimal attenuation. and scattering to achieve a high local intensity ultrasound focused on as little area as possible.

The essence of the invention

The object of the invention is to achieve the required sufficiently high local intensity of the ultrasonic field enabling the treatment of superficial lesions, in particular wounds and skin defects, including their debridement.

The above object is achieved by a device for generating ultrasound of high local intensity formed by a chamber and an outer shell defining a cavity. The inner surface of the outer shell is in the shape of a rotating paraboloid with a base and a top, and the cavity of the outer shell is adapted to contain a liquid medium. The outer shell is connected to the base in the base by means of a threaded connection in a chamber in which a piezoelectric transducer is arranged between the first "O" ring and the second "O" ring, on which a cover nut connected by a threaded connection to the chamber rests. A matching acoustic plate is further arranged between the cavity and the piezoelectric transducer. The outer shell is terminated at the apex by an opening which is provided with a nut with an annular recess in which resilient circular washers securing the membrane are arranged.

In a preferred embodiment, the outer jacket in the vicinity of the threaded connection with the chamber is further connected to a vent for the supply and / or discharge of a liquid medium.

The object of the invention is to concentrate the ultrasonic energy generated by the piezoelectric transducer with a planar radiating surface and normal power into the application site so that the focusing achieves a therapeutically desired local amplification of the ultrasonic energy intensity. Such locally amplified ultrasound can then provide the necessary energy in the surface layers of the lesion (for example a wound or a skin or mucous membrane defect) necessary to promote healing.

-4EN 2020 - 214 A3 thermal effects and possible wound debridement. The required focus is achieved by reflecting the ultrasonic waves on the inner surface of the cavity formed in the form of a rotating paraboloid.

The device for generating ultrasound of high local intensity uses reflections of waves in a cavity filled with a liquid medium suitable for the propagation of ultrasonic waves.

The device for generating ultrasound of high local intensity uses reflections of waves in a cavity bounded by a second order surface in the form of a rotating paraboloid.

The device for generating ultrasound of high local intensity uses the reflections of the waves in the cavity bounded by the second order surface in the form of a rotating paraboloid and concentrates the reflected ultrasound waves in the focus of this paraboloid.

The device for generating high local intensity ultrasound uses reflections of waves in a cavity bounded by a second order surface in the form of a rotating paraboloid and concentrates the reflected ultrasound waves in the focus of this paraboloid, a circular membrane of substantially smaller dimensions than the cavity.

The high local intensity ultrasound device uses reflections of waves in a cavity bounded by a second order surface in the form of a rotating paraboloid and the reflected ultrasound waves concentrate in the focus of this paraboloid, a circular membrane of substantially smaller dimensions than the cavity is located in the focus and the membrane is open to free space outside the cavity.

The device for generating high local intensity ultrasound uses reflections of waves in a cavity bounded by a second order surface in the form of a rotating paraboloid and the reflected ultrasound waves concentrate in the focus of this paraboloid, a circular membrane of substantially smaller dimensions than the cavity is placed in the focus and the membrane is recessed. into the free space outside the cavity, into this depression an ultrasonic conductive gel or similar means is introduced, which ensures contact with the lesion and transmits therapeutically necessary ultrasound waves with significantly locally increased intensity, i.e. power concentrated on a small area corresponding to the dimensions of the depression. as well as the diaphragm - are much smaller compared to the dimensions of the transducer and cavity.

The device can achieve effective healing and / or cavitation effects and thus support, for example, the process of wound healing or debridement, while suppressing the risk of spreading infectious agents or damaging the wound with a mechanical vibrating tool, as in current technical solutions. However, the power of the ultrasonic transducer itself does not have to be large and the present device is easy to manufacture.

Explanation of drawings

The essence of the invention is further elucidated on the basis of examples of its embodiment, which are described with the aid of the accompanying drawings, where:

Giant. 1 shows a perspective view of a device for generating high local intensity ultrasound without a spout;

Giant. 2 shows a longitudinal section of a device for generating ultrasound of high local intensity in the form of a paraboloid, without a spout and with a piezoelectric transducer;

Giant. 3 shows in cross section a detail of the arrangement of the piezoelectric transducer in the device;

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Giant. 4 shows in cross section a detail of the top of the outer casing of the device with the first embodiment of the application system;

Giant. 5 shows a perspective cross-sectional view of a device for generating ultrasound of high local intensity without an outlet with a bearing of sealing "O" rings;

Giant. 6 shows a longitudinal section of a device for generating ultrasound of high local intensity in the form of a paraboloid, with a vent and a piezoelectric transducer; and

Giant. 7 shows in cross section a detail of the top of the outer shell of the device with the second embodiment of the application system.

Examples of embodiments of the invention

These embodiments illustrate exemplary embodiments of the invention, which, however, have no limiting effect on the scope of protection. In the above drawings, the present solution is illustrated by means of embodiments of a device for generating ultrasound of high local intensity, using wave reflections on the inner surface of a rotating paraboloid.

Example 1: Apparatus for generating high local intensity ultrasound without a vent

As can be seen from Figures 1 to 5, the device for generating high local intensity ultrasound in the first embodiment comprises a piezoelectric transducer 1 which is resiliently mounted in the chamber 2. An outer shell 17 is connected to the chamber 2 by a threaded connection, the apex of which formed by the opening 10. is adapted to apply a therapeutic ultrasound to a desired location on the surface 15 of the patient's body. To ensure a flexible mounting and at the same time seal the piezoelectric transducer 1 in the chamber 2, this transducer is arranged between the first "O" ring 4 and the second "O" ring 5. To ensure high local ultrasonic field intensity, the inner surface 8 of the outer shell 17 has the shape of a rotating paraboloid. wherein a liquid medium 3 is present in the cavity 7 of the outer shell 17. A matching acoustic plate 16 is arranged in the space between the piezoelectric transducer 1 and the cavity 7. This can be made of a material of suitable acoustic impedance with a thickness equal to an odd multiple of one quarter of the wavelength ultrasonic waves, the acoustic impedance Zm of the material used to make the matching acoustic plate to be close to:

Zm = y ^ Zr'Zz where Zt is the acoustic impedance of the piezoelectric transducer 1 and Z1 is the acoustic impedance of the liquid medium 3 filling the cavity 7. Assuming the piezoelectric transducer is made of PZT ceramic material (acoustic impedance approx. 33 MRayl) and liquid medium 3 filling the cavity 7 formed by glycerol (acoustic impedance 2.5 MRayl), the acoustic impedance of the matching acoustic plate 16 should be around 9 MRayl, which may correspond to, for example, a ceramic-cured epoxy resin or pyrolytic carbon.

To ensure the sealing of the piezoelectric transducer 1, a cover nut 6 is screwed into the upper part of the chamber 2. The opening 10 of the outer shell 17 is terminated by a nut 11 with an annular recess in which resilient circular washers 12 are arranged to serve to fasten the membrane 13.

The function of the device is as follows: the piezoelectric transducer 1 is excited in a known manner by an electrical harmonic signal, so that it generates a mechanical ultrasonic wave propagating in the vertical axis in both directions, and a circular piezoelectric ultrasonic transducer can be used as the piezoelectric transducer 1. In the direction facing away from the closed cavity 7, the propagation of this wave is prevented by air with an extremely low acoustic impedance, or it is damped by a suitable damping material. This damping material can be, for example, an epoxy resin with tungsten or aluminum (Al2O3) particles, with an acoustic impedance value of approximately 20 MRayl and

-6GB 2020 - 214 A3 attenuation 10 to 30 dB / cm.MHz, or silicone rubber, also with high acoustic attenuation (more than 30 dB / cm.MHz) and acoustic impedance approx. 1 MRayl. These materials are intended to absorb residual ultrasonic waves generated in the opposite direction, but their use is not absolutely necessary for the proper functioning of the technical solution according to the invention, but can improve the binding and transmission of ultrasound generated by piezoelectric transducer 1 to other parts of the device.

In the direction facing the cavity 7, the ultrasonic waves generated by the piezoelectric transducer 1 propagate through the matching acoustic plate 16 further into the liquid medium 3 filling the closed cavity 7. The matching acoustic plate 16 has a thickness of one quarter of the wavelength of ultrasonic waves propagating in its material, the acoustic impedance of this material should be close to the square root of the product of the acoustic impedances of the material of the piezoelectric transducer 1 and the liquid medium 3 with which the cavity 7 is filled. As already calculated above, the acoustic impedance of the material of the matching acoustic plate 16 should optimally be around 9 MRayl, which may correspond, for example, to a ceramic-cured epoxy resin or pyrolytic carbon. In this technical solution, as much of the ultrasonic waves as possible pass into the liquid medium 3 located in the cavity 7 and the waves reflected at the interface of the piezoelectric transducer 1 and the liquid 3 in the cavity 7 are also canceled by their phase difference. Thus, the ultrasonic waves propagate in a straight line in the direction of the vertical axis of the circular piezoelectric transducer 1 through the liquid medium 3 filling the cavity 7, since no transverse waves are applied in the liquid. The longitudinal ultrasonic waves strike the inner surface 8 of the outer shell 17. This inner surface 8 has the shape of a rotating paraboloid, and thus all the reflected waves are directed into the focus of the paraboloid. In this focus, a thin membrane 13 is arranged between a pair of circular resilient washers 12. This membrane 13 is slightly tensioned by the pressure of the liquid medium 3 filling the cavity 7. Filling the cavity 7 with liquid medium 3 is ensured before assembling the outer shell 17, chamber 2 and cover nut 6 the slight pressure of the liquid medium 3 biases the membrane 13. Ultrasonic waves reflected from the inner surface 8 directly into the focus in which the membrane 13 is located are transmitted to this membrane 13. Ultrasonic oscillations are mechanically excited on this membrane 13, which excites further propagation of ultrasonic waves in the region of an annular funnel-shaped depression filled with immersion liquid 14 or gel 14. by which ultrasonic waves are transmitted directly to the lesion on the patient's body surface 15, since the nut 11 with an annular recess, the device is applied to the lesion. In this way, a significantly higher surface density of ultrasonic intensity is created at the lesion site on the surface 15 of the patient's body, transferring the locally required energy and thus providing the desired therapeutic effects. Even with the use of conventional piezoelectric transducers 1 with the usual surface power intended for physical therapy (of the order of units W / cm ² ), the required amplification of the ultrasonic wave intensity is achieved at the application site at the apex formed by the opening 10 of the outer shell 17.

Alternatively, the annular depression area may be filled with an applicator pad made as a solid gel body (made, e.g., of polydimethylsiloxane, PDMS) or as a thin-walled plastic bag filled with a suitable liquid (glycerin, degassed water, silicone oil, etc.). This pad, especially when wetted at both the contact surfaces 10 with the opening 10 and with the patient's body surface 15, allows firm adhesion and good transmission of focused ultrasound, as well as partial paraboloid movement across the lesion to hit the desired lesion sites with focused ultrasound.

Example 2: Apparatus for generating high local intensity ultrasound with a vent

The device in the second embodiment shown in Figs. 6 and 7 is an analogous device according to the first embodiment described above, wherein the outer casing 17 is further provided with a vent 9 which can be used to, respectively. from the cavity 7 to feed, resp. drain the liquid medium 3 as required. Fig. 7 shows the arrangement of a pair of resilient circular washers 12 above and below the membrane 13 in the space of the outer shell 17.

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Industrial applicability

Using the reflection on the walls of the rotating paraboloid, the device provides ultrasound of high local intensity, i.e. considerable ultrasonic power applied to a small defined area.

Claims (2)

PATENT CLAIMS A device for generating ultrasound of high local intensity, comprising a chamber (2) and an outer shell (17) defining a cavity (7), the inner surface (8) of the outer shell (17) having the shape of a rotating paraboloid with a base and a top, and the cavity (7) of the outer shell (17) is adapted to contain a liquid medium (3), the outer shell (17) being connected in the base by means of a threaded connection to a chamber (2) in which a piezoelectric transducer (1) is arranged between a first "O" ring (4) and a second "O" ring (5), on which a cover nut (6) connected by a threaded connection to the chamber (2) rests, the outer shell (17) terminating in an aperture (10) at the apex. which is provided with an annular recess nut (11), characterized in that an adaptive acoustic plate (16) is arranged between the cavity (7) and the piezoelectric transducer (1), and further in that an annular recess nut (11) is arranged in the annular recess nut (11). resilient circular washers (12) securing the membrane (13) are provided. Device according to claim 1, characterized in that the outer casing (17) is further connected to the outlet (9) for the supply and / or discharge of the liquid medium (3) in the vicinity of the threaded connection with the chamber (2).