CZ2020192A3 - Acoustic wave of the head of a therapeutic ultrasound device - Google Patents

Abstract

The subject of the technical solution is an acoustic waveguide (19) of the head (20) of an ultrasonic therapeutic device based on the Fresnel lens principle. The ultrasound therapy device comprises an electric excitation signal generator (30) connected to the head (20) and the acoustic waveguide (19). The acoustic waveguide (19) has the shape of a cylinder, which is terminated at the upper end by a base (1) and at the lower end by a face (2) and which comprises a concentrically arranged inner cylinder (34) extending from the face (2), a circular notch (3). in the form of an annulus and an outer shell (35). The base (1) of the acoustic waveguide (19) is attachable to the active surface of the head (20), the acoustic waveguide being adapted to propagate the focused ultrasonic waves (5) from the forehead (2) towards the surface (7) of the patient's body. The circular notch (3) can be closed on the face side (2) by a seal (4). The acoustic waveguide (19) may be made of steel, preferably stainless steel, or an aluminum alloy, preferably aluminum alloy 2024 or superdural.

Description

Acoustic waveguide of the head of a therapeutic ultrasound device

Field of technology

The present invention relates to an acoustic waveguide (or ultrasonic adapter) of a head of a therapeutic ultrasound device based on the Fresnel lens principle.

State of the art

Ultrasound energy is widely used in physical medicine, especially in therapy, when we want to transfer the energy of ultrasound 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 extensibility (scars, conditions after muscle and joint capsule injuries), accelerates wound healing, etc.

U.S. Pat. No. 6,315,741 B1 discloses a method and apparatus for medical procedures using high intensity concentrated ultrasound. This patent addresses a form of ultrasound application for tissue cauterization, which is another promising area of application of ultrasound in therapy. The invention is directed to a telescopic acoustic coupler and the possibility of an adjustable focus.

A similar problem is addressed by U.S. Pat. No. 4,485,569 A, which describes an ultrasound diagnostic and therapeutic device and method of using the same. The present invention discloses, inter alia, a truncated pyramid focusing head with a concave ultrasonic transducer located in the circular base of the pyramid, focused on a small circular membrane at the tip of the pyramid, the resulting cavity being filled with a suitable fluid (e.g. water) with slight overpressure causing convex arching. thus improving the transmission of focused ultrasound energy to the tissues to which the pyramid tip is applied. The described solution can also be used for coagulation and hemostasis. 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 several sub-transducers, most often annular shapes, placed concentrically.

Another U.S. Pat. No. 7,297,131 B2 discloses a therapeutic ultrasound system for introducing ultrasound into a catheter. It is a complex device combining an elastic catheter with ultrasound transmission from the transducer using an amplifying ultrasonic waveguide, the so-called sonicator, made of a special flexible alloy and cooling with saline applications.

The use of ultrasonic amplification waveguides (sono-amplifiers, 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 point of contact with the transducer and whose length is equal to the wavelength of the transmitted ultrasonic waves. Depending on the shaping method, there are exponential, stepped, conical and cylindrical sonicators. The gain is given by the ratio of the start and end diameters of the waveguide. A special type is the Fourier sonoficator. In English, amplifying ultrasonic waveguides (sonoficators) are usually referred to simply as ultrasonic tubes (untrasound hom).

-1 CZ 2020 - 192 A3

Among Czech patents, the CZ 291491 B6 patent, which describes high-performance ultrasonic devices, especially for inorganic preparations, deals with this issue. In addition, this patent introduces the sensing of the amplitudes of the ultrasonic oscillations transmitted by the waveguide with the possibility of their use for fine-tuning the optimal resonant frequency of the transducer.

Another U.S. Pat.

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 location within the body where thermal and mechanical effects that induce thrombolysis, coagulation or ablation are required. 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 amounts of energy on 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.

Another U.S. patent application US 2014276055 A1 describing reflex ultrasound technology for dermatological treatment focuses on dermatological and cosmetic ultrasound applications. It determines the need for both focusing and defocusing of the ultrasonic wave beam. For this purpose, it highly sophisticatedly applies variously shaped piezoelectric transducers, convex and concave acoustic lenses, parabolic and elliptical mirrors as well as phase shifts of individual wave sources. The solution of spatial combinations of cylindrical and other curved surfaces directing ultrasonic waves to the required places is unique.

U.S. Pat. No. 2010022889 A1, which discloses an ultrasonic head for an ultrasound patient treatment device, addresses the placement of an ultrasonic applicator on a patient's body surface with a resilient two-piece attachment into which a vacuum is applied. to the patient's body surface, the applicator according to the invention also ensuring the smooth introduction of the required amount of gel forming the necessary thin layer between the transducer face and the patient's body surface. However, this patent does not address the issue of placing the ultrasound applicator at one site in the patient's body (static application), which involves the risk of damaging those tissue sites exposed to wave oscillations, while the nodal sites are not treated with ultrasound.

Another European patent EP 2366430 B1 describing an ultrasound application device, on the other hand, relates to a hand-held applicator for the dynamic administration of therapeutic ultrasound. In particular, it deals with the issue of unwanted heating of the hand applicator head, which adversely affects both the patient and the operator. The solution lies in the construction and arrangement of a special cooler located inside the hand applicator.

- 2 CZ 2020 - 192 A3

International patent application WO 2008002773 A2, which describes an ultrasonic device for wound care and a method of using this device, is directed to the treatment of wounds. A funnel-shaped attachment (hemisphere) made of 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. The ultrasound propagating through this environment has sufficient intensity to induce borderline cavitation, and the chemical (radical) and mechanical effects of cavitation on the wound surface ensure its debridement and support its healing.

U.S. Pat. No. 9,345,909 B2, which describes the treatment of skin ulcers, introduces a combination of 1 to 3 MHz ultrasound and interference or amplitude modulated medium frequency electric currents for the treatment of trophic defects associated with skin surface disruption.

Another U.S. Patent No. 8979775 B2 discloses a combined ultrasound and phototherapy applicator combining the therapeutic application of light and ultrasound. It introduces a unique arrangement of light flux transmission through the gaps between annulus-shaped transducers of the annulus.

The essence of the invention

The object of the invention is to provide a new construction which makes it possible to concentrate the ultrasound energy from the head of the ultrasound device intended for physical therapy to the application site so that the focusing achieved the therapeutically desired volume density of the ultrasound energy. For this purpose, an acoustic waveguide in the form of an ultrasonic adapter was developed, ensuring the required focusing and optimal introduction of ultrasound energy into the treated tissues.

The acoustic waveguide is designed in such a way that after its placement on the active (front) surface of the ultrasound therapy device head, it allows the focused introduction of ultrasound energy to the desired location of treated tissues, where the therapeutically required volume density of ultrasound energy is created.

The above object is achieved by means of an acoustic waveguide of the head of an ultrasound therapeutic device based on the Fresnel lens principle. The acoustic waveguide has the shape of a cylinder which terminates in a base at the upper end and a front at the lower end and which comprises a concentrically arranged inner cylinder, a circular annular notch and an outer shell, these elements not reaching the base of the acoustic waveguide. The base of the acoustic waveguide is attachable to the active surface of the head and the acoustic waveguide is adapted to propagate the focused ultrasound waves from the forehead towards the surface of the patient's body.

Preferably, the circular notch is closed on the face side by a seal and the acoustic waveguide is preferably made of steel, preferably stainless steel, or aluminum alloy, preferably aluminum alloy 2024 or superdural.

The present invention further provides an ultrasound therapy apparatus comprising an electrical excitation signal generator coupled to a head and an acoustic waveguide as described above. The head is formed by a jacket (e.g. an outer jacket and an inner jacket) and an active surface, the inner conductor of the electric excitation signal being guided inside the head to a piezoelectric transducer for generating ultrasonic waves. An acoustic waveguide base is further attached to the active surface of the head covering the piezoelectric transducer, and an acoustic attenuation material (e.g., a first acoustic impedance block and a second acoustic attenuation block) is arranged above the piezoelectric transducer.

Preferably, the active surface of the head forms a piezoelectric transducer or a matching cover layer which is arranged below the piezoelectric transducer, serves to protect it and at the same time provides impedance matching during ultrasound transmission to the body.

-3GB 2020 - 192 A3

Preferably, the front of the acoustic waveguide is immersed in the application fluid defined by the patient's body surface and the application bell formed by the application roller. The application roller can be provided at the lower end with an intermediate ring or at the upper end with a cover with an opening for the acoustic waveguide, this opening being provided with a resilient sealing ring. The application bell is further preferably connected to a source of application liquid and / or to a collecting vessel.

Alternatively, the face of the acoustic waveguide may be arranged on an applicator pad which is deposited on the surface of the patient's body and is filled with the applicator fluid or formed of an acoustically well conductive gel.

The acoustic waveguide is based on the principle of a Fresnel lens and is realized, however, not for the wavelengths of light, but for the wavelengths of ultrasound. From a physical point of view, the Huygens-Fresnel principle is used. According to this principle, the propagation of each wave is characterized by its ability to penetrate under shading, ie behind obstacles, by diffraction (bending). This physical principle makes it possible to construct a new surface of the wavefront by constructing the envelope of the elementary waves created around each point of the wavefront at the previous moment. This is how the bending of the waves behind the obstacle can be explained. The physical principle thus described is the Huygens principle itself, which, however, does not make it possible to find the amplitudes of oscillations propagating in different directions. This shortcoming is eliminated by the Fresnel numerical method based on a detailed idea of wave propagation with respect to amplitude and phase oscillations.

For the purposes of the present invention, it can be assumed that the waves will come from at least two concentric bands separated from each other by a circular notch: a first, central zone of circular cross-section (inner cylinder) surrounded by a second shading zone (circular notch) another, concentric zone, again in the shape of an annulus, fits, which represents another, third zone (outer shell), from which the waves will also propagate. The construction of concentric bands could be continued. All such bands, ie the central band, the shading band and the concentric band, which are connected in a common base - the base on which the plane wave of ultrasonic waves will propagate, propagating longitudinally in the direction of the axis of the circular piezoelectric transducer. In accordance with physical theory, for the radius of the generally k-th band, the relation holds:

where:

Pk '] Q is the radius of the k-th band, ro is the distance from the front of the acoustic waveguide to the focus into which the waves will be focused,

Λ is the radius of the wave incident on the base of the acoustic waveguide £ is the number of bands λ is the wavelength of the ultrasound

Considering the analogy with light, the radius ^ jc is equal to the radius of the circular hole in the screen. Then the following will apply to:

-4EN 2020 - 192 A3

The ultrasonic waves will be transmitted from the piezoelectric transducer of the head to the base of the acoustic waveguide as a plane wave, so that:

p píR + tp p ¹ k = lim ^L ---— = -— λ r _Q R

With a radius of effective area of the ultrasonic piezoelectric transducer of 25 mm, p = 12.5 mm, the number of bands is eg k = 3. The wavelength of ultrasound with a typical therapeutic frequency of 1 MHz in an acoustic waveguide made of eg aluminum will be:

6320m / s

1000000 Hz = 6.32 mm

The focus will be at a distance of:

= 8.24 mm

According to the formula derived above, the following can be calculated for the radii of the individual bands:

with the result:

^ = 7.2 mm p ₂ = 10.2 mm p. = P-12.5 mm

The strength of the base of the acoustic waveguide through which the plane ultrasonic wave propagates from the piezoelectric transducer should correspond to a quarter wavelength (1.58 mm for aluminum) or its odd integer multiple, so that the waves reflected from the metal-air interface are reflected in the opposite phase, than the waves at the head-acoustic waveguide interface are reflected, and so these parasitic reflected waves with opposite phases cancel each other out. The whole acoustic waveguide (not counting

-5GB 2020 - 192 A3 base) should be about ten times the wavelength (63.2 mm). For an acoustic waveguide, we consider the longitudinal propagation of ultrasonic waves.

The heads of physico-therapeutic ultrasound devices produce a maximum power density of 2 W / cm ² with an area of the active part of the head of about 5 cm ² . This performance is not sufficient to achieve the effects of debridement and the therapeutically required gentle cavitation on the surface of the treated wounds. In addition, ultrasonic radiation cannot be focused in any way. The acoustic waveguide according to the invention is able to focus a power of 10 W on an area of several mm ² and thus achieve the required power density at the point of action of several hundred W. It is also possible to construct a separate head, which will already include structurally acoustic waveguide according to the invention integral part.

The advantage is that the acoustic waveguide according to the invention is easy to manufacture and can be applied to basically any head of a medical device for ultrasound physical therapy with a planar active surface of the head - therapy probe or applicator, where ultrasonic waves can be focused due to the use of this acoustic waveguide. to the required sites affected by the tissues and to achieve significantly higher wave intensity and acoustic pressure.

Clarification of drawings

The essence of the invention is further elucidated on the basis of exemplary embodiments thereof, which are described with the aid of the accompanying drawings, in which:

Giant. 1 shows a basic embodiment of an acoustic waveguide (A, B) and an embodiment of an acoustic waveguide with a seal (C, D) in plan view (A, C) and side section (B, D);

Giant. 2 shows an embodiment of a therapeutic apparatus for ultrasound physical therapy with an open application roller;

Giant. 3 shows a detail of the application roller;

Giant. 4 shows an embodiment of a therapeutic apparatus for ultrasound physical therapy with a closed application bell; and

Giant. 5 shows an embodiment of a therapeutic apparatus for ultrasound physical therapy with an application pad.

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. The invention will be explained in more detail with reference to exemplary embodiments with reference to the corresponding drawings.

The basic embodiment of the acoustic waveguide 19 on the principle of a Fresnel lens is shown in Figs. 1A and 1B. The acoustic waveguide 19 in this embodiment is realized as an ultrasonic adapter which has the shape of a cylinder, in which a circular notch 3 in the shape of an annulus extending almost the entire length of the cylinder from the lower end is formed, as can be seen in Fig. 1A. This cylinder is terminated at the upper end by a base 1 and at the lower end by a face 2. In plan view, the cylinder has an inner cylinder 34 in the middle and an outer shell 35 in the shape of an annulus at the edge between which there is a circular notch 3. The cylinder base 1 must have a perfect plane and its surface is polished. The surface of the cylinder face 2 is also polished, which means that the lower end of the inner cylinder 34 and the inner shell 35 in the form of an annulus are polished. From the polished surfaces of the cylinder of the acoustic waveguide 19 will be

-6GB 2020 - 192 A3 propagate elementary waves, which will add up, and thus focus on the focus on the axis of the ultrasonic adapter at a distance of about 8 mm from the forehead 2.

A preferred embodiment of the acoustic waveguide 19 on the principle of a Fresnel lens is shown in Figs. The acoustic waveguide 19, as described above and in Figs. 1A and 1B, comprises a circular notch 3 on the face side 2 further closed by a seal 4 in the shape of a circular notch 3.

The ultrasound physical therapy therapy apparatus is shown in two embodiments in Figures 2 and 3. The ultrasound physical therapy therapy apparatus in this embodiment includes an electrical excitation signal generator 30 which is connected via a shielded electrical excitation signal lead 29 to a connector 28; which is arranged on the head 20 of the device and is connected to the internal line 25 of the electrical excitation signal. The head 20 of the device consists of an outer casing 22 in which an inner casing 23 is arranged. Inside the inner casing 23 a piezoelectric transducer 24 is arranged, which is connected to the inner conductor 25 of the electric excitation signal and electrical excitation signal. The piezoelectric transducer 24 converts the excitation harmonic electrical signal to ultrasound. Its thickness must satisfy the Ά wavelength condition. Today, the material is usually piezoelectric PZT ceramics or quartz cut. To suppress reflections of ultrasonic waves generated in the opposite direction, an acoustic attenuation material is arranged in the inner shell 23 above the piezoelectric transducer 24, namely a first acoustic impedance block 26 with a suitable acoustic impedance material allowing impedance matching, effective damping. The material can be, for example, an epoxy resin with tungsten or aluminum (Al2O3) particles, with an acoustic impedance value of approximately 20 MRayl and an attenuation of 10 to 30 dB / cm.MHz. Above it can be placed a second block 27 acoustic attenuation with a material with high acoustic attenuation (more than 30 dB / cm.MHz) and also a suitable acoustic impedance minimizing reflections (eg pyrolytic carbon with an acoustic impedance value of approximately 7 MRayl, or aluminum itself submicron dust or silicone gel), which is designed to absorb residual ultrasonic waves generated in the opposite direction. These blocks 26, 27 can be combined into one block with the required properties.

The acoustic waveguide 19 itself is connected to the head 20 of the instrument. The perfectly flat, polished base 1 of the acoustic waveguide 19 is tightly applied to the also planar active surface of the head 20. This active surface is formed either by an adaptive cover layer 21, which is located under the piezoelectric transducer 24, serves as its protection and provides impedance matching during transmission. In each case, however, a contact immersion viscous liquid 8, represented for example by oil or a thinner gel, must be applied between the active surface of the head 20 and the base 1 of the acoustic waveguide 19. If an adaptive cover layer 21 is present, it is necessary that its thickness corresponds to% of the wavelength of the ultrasonic waves and that the acoustic impedance Z _m of the material used is close to:

where Zt is the acoustic impedance of the piezoelectric transducer 24 and Z1 is the acoustic impedance of the acoustic waveguide 19 material. Similar physically given conditions must be met even if the acoustic waveguide 19 with its base 1 is applied directly to the piezoelectric transducer 24.

The acoustic waveguide 19 is made of a material that well transmits longitudinal ultrasonic waves with low attenuation and suitable acoustic impedance. Such materials can be e.g.

-7 CZ 2020 - 192 A3 aluminum 2024, superdural or other polishable aluminum alloys, while stainless steel and other materials with similar properties can also be used.

The acoustic waveguide 19 is intended to focus the ultrasonic waves 5 from the head 20, this focusing being possible only in a suitable medium between the face 2 of the acoustic waveguide 19 and the surface 7 of the patient's body. This medium must have liquid or quasi-liquid properties and may be an application liquid 9, for example degassed water or other suitable liquid or emulsion or salt solution or micellar colloid, characterized by good ultrasonic conduction with attenuation of max. About 1 dB / cm, acoustic impedance close soft tissue (1.6 to 1.7), suitable viscosity (maximum up to 1,500 mPa.s, which corresponds to the dynamic viscosity of glycerol) and biocompatible properties, possibly also disinfectant and healing promoting effects.

The circular notch 3 of the cylinder is preferably perfectly closed by means of a seal 4. The reason is that application fluid 9 cannot penetrate into the circular notch 3. Conversely, between the patient body surface 7 and the acoustic waveguide face 2, this application fluid 9 must play an irreplaceable role Therefore, both the treated part of the surface 7 of the patient's body, including the lesion 6, and the face 2 of the acoustic waveguide 19 must be immersed in this application fluid 9, thus ensuring the transmission of ultrasound to the destination. After the ultrasound penetrates the human body itself, or the body of another treated living organism, the already focused ultrasound propagates according to known physical laws, provided that it does not encounter obstacles with significantly different impedances on which it is strongly reflected, such as bones.

If it is not possible to immerse the treated part of the patient's body surface 7 in the application fluid 9, then the acoustic waveguide 19 must be provided with an application bell 10 or an application roller 31, which is filled with the application fluid 9.

Since the main use of the acoustic waveguide 19 can be seen in the ultrasonic debridement of wounds and their treatment with ultrasound with energy focused on the lesion surface 6, e.g. in the following manner, which is shown in Fig. 2. The patient is positioned so that the trophic defect on the surface 7 of the body is placed in a horizontal plane and directed upwards. An application roller 31 made of, for example, glass or poly (methyl methacrylate) or other suitable, preferably transparent material is applied to the defect area. This applicator roller 31 is formed only by a shell, i.e. without bases, as can be seen in Fig. 3. For better, more comfortable and tighter adhesion to the intact surface of the patient body 7 surrounding the lesion 6, at the lower end. It is important that the applicator roller housing 31 be as transparent as possible and that a physician or other competent health care professional be able to observe the effect of focused ultrasound 5. The applicator roller 31 is applied to the intact portion of the patient body surface 7 so that the defect is surrounded by . The applicator roller 31 is applied close to the treatment site, i.e. the lesion 6 on the surface 7 of the patient's body. If necessary, the edges of the application roller 31 resting on the intact surface 7 of the body can be lined with a biocompatible waterproof material (e.g. silicone or polyurethane foam Vivano®Med used for vacuum wound therapy). In the application cylinder 31, the height of which must be greater than the focal length of the acoustic waveguide 19, the application liquid 9 is filled into the level 32 so that the face 2 of the acoustic waveguide 19 is immersed deep enough with respect to the focal length. The focused ultrasound wave 5 is applied to the lesion site 6 thus prepared. the whole defect - lesion 6 is then treated by a slight vertical movement in the direction of the axis of the acoustic waveguide 19.

In contrast to the debridement methods described above, in this way the defect can be treated gently and effectively without compromising the safety of the patient or medical staff. Application liquid 9 plays both a disinfectant and a healing corner, and at the same time prevents the dispersal of pathogenic microorganisms and further endangering the patient and staff. After the procedure, the liquid is drained

-8EN 2020 - 192 A3 by means of a drain cock 13 via a drain hose 15 into a collecting vessel 17 for collecting the discharged application liquid. The applicator roller 31 can then be disposed of as infectious material or re-sterilized.

A more sophisticated embodiment of the application bell 10, applicable in principle to any positioned part of the body, is shown in Fig. 4.1. The basis here is the use of an application bell 10 in the form of an application cylinder 31 provided with a cover 36 with an opening in place of the upper base. An acoustic waveguide 19 in the form of a cylinder is inserted through this opening, which is sealed in the application bell 10 by means of a flexible sealing ring 11. This can be made of a material such as neoprene or other suitable flexible and water-resistant material such as rubber or silicone. Such a sealing method prevents leakage of the application fluid 9, and at the same time allows rotationally oscillating movement and to some extent vertical movement of the acoustic waveguide 19 and thus concentrating the focused ultrasonic waves 5 on desired areas of the patient's body surface 7 or focusing or defocusing the ultrasonic waves 5. The application liquid 9 is filled into the application bell 10 via an application liquid source 16 (e.g. a filling funnel) or other device intended for filling the application liquid 9, which flows through the filling hose 14 through an open filling cock 12 and fills the entire application bell space 10. Therefore, It is suitable that the filling of the application bell 10 with the application liquid 9 takes place under a slight pressure, e.g. the pressure provided by the higher position of the place from which the application bell 10 is filled. The drain cock 13 and the drain hose 15, which open into the collecting container 17, serve to drain the application liquid 9. The point of contact 18 of the application bell 10 with the intact surface of the patient's body 7 must be solved to avoid injury to the body surface, i.e. without sharp edges. If necessary, the edges of the application bell 10 resting on the surface 7 of the patient's body can be lined with a biocompatible waterproof material (e.g. silicone or Vivano®Med polyurethane foam used for vacuum wound therapy).

The application pad 37 made as a solid gel body (made e.g. of polydimethylsiloxane, PDMS) or as a thin-walled plastic bag filled with suitable liquid (glycerin, degassed water, silicone oil, etc.). This cushion 37, especially when wetted at both interfaces with the acoustic waveguide face 2 and the patient's body surface 7, allows firm adhesion and good transmission of the focused ultrasonic waves 5, as well as partial movement of the head with the focusing acoustic waveguide 19 to focus. focused ultrasound waves 5 to the desired sites of the lesion 6.

Industrial applicability

The acoustic waveguide based on the Fresnel lens principle is intended primarily for surface and slightly subsurface applications, especially for the treatment of trophic skin and subcutaneous defects and for the treatment of wounds. The acoustic waveguide can be used as an adjunct to a therapeutic ultrasound device - then a fixation must be provided between the acoustic waveguide and the individual head of a particular ultrasound therapy device, or a separate head structurally incorporating the acoustic waveguide as an integral part can be constructed.

Claims (10)

PATENT CLAIMS Acoustic waveguide (19) of a head (20) of an ultrasonic therapeutic device based on the Fresnel lens principle, characterized in that it has the shape of a cylinder, which is terminated at the upper end by a base (1) and at the lower end by a face (2) and which comprises concentrically an inner cylinder (34), an annular notch (3) in the form of an annulus and an outer shell (35) arranged and extending from the face (2), the base (1) of the acoustic waveguide (19) being attachable to the active surface of the head (20), the acoustic waveguide is adapted to propagate the focused ultrasound wave (5) from the forehead (2) towards the surface (7) of the patient's body. Acoustic waveguide (19) according to Claim 1, characterized in that the circular notch (3) is closed on the face side (2) by a seal (4). Acoustic waveguide (19) according to claim 1, characterized in that it consists of steel, preferably stainless steel, or aluminum alloy, preferably aluminum alloy 2024 or superdural. Ultrasound therapy device comprising an electrical excitation signal generator (30) connected to a head (20) and an acoustic waveguide (19) according to any one of the preceding claims, characterized in that the head is formed by a shell and an active surface, the inside of the head (20) an internal electrical excitation signal line (25) is routed to the piezoelectric transducer (24) for generating ultrasonic waves, the base (1) of the acoustic waveguide (19) being attached to the active surface of the head (20) and acoustic attenuated material arranged above the piezoelectric transducer . Ultrasound therapy device according to claim 4, characterized in that the active surface of the head (20) is formed by a piezoelectric transducer (24) or a matching cover layer (21) arranged below the piezoelectric transducer (24), between the base (1) and the active surface the head (20) is coated with an immersion viscous liquid (8). Ultrasound therapy device according to claim 4, characterized in that the face (2) of the acoustic waveguide (19) is immersed in the application fluid (9) defined by the patient body surface (7) and the application bell (10) formed by the application roller (31) . Ultrasound therapy device according to claim 6, characterized in that the application roller (31) is provided at the lower end with an intermediate ring (33). Ultrasound therapy device according to claim 6, characterized in that the application roller (31) is provided at the upper end with a cover (36) with an opening for an acoustic waveguide (19), this opening being provided with a resilient sealing ring (11). Ultrasound therapy device according to Claims 6 to 8, characterized in that the application bell (10) is connected to a source (16) of application fluid (9) and / or to a collecting vessel (17). Ultrasound therapy device according to claim 4, characterized in that the face (2) of the acoustic waveguide (19) is arranged on an application pad (37) which is mounted on the surface (7) of the patient's body and is filled with application fluid (9). or formed by a gel.