A fast pulsed electrohydraulic (EH) shockwave generator with improved acoustic wavefront.

Abstract

To provide an apparatus and method for generating therapeutic compressed acoustic waves (e.g., shock waves) with an improved acoustic wavefront. In one embodiment, an enclosure (1004) is defined by a chamber (1008) and a shockwave outlet (1012), the chamber configured to be filled with a liquid. A plurality of electrodes defining one or more spark gaps (200) and an acoustic reflector (1020) can be disposed within the chamber, and a pulse-generation system configured to apply voltage pulses to the electrodes at a rate between 10 Hz and 5 MHz. An improved acoustic wavefront is achieved via the freeform acoustic reflector and / or a stable spark gap location. The freeform acoustic reflector is designed according to a disclosed method that includes iterating the reflector shape using spline interpolation based on defined variables. Additionally, a stable spark gap location is achieved via a single servo motor (1024) that simultaneously adjusts both electrodes.

Description

[Technical field]

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 447,191, filed January 17, 2017, which is incorporated herein by reference in its entirety.

[0002] 1. FIELD OF THEINVENTION The present invention relates generally to the therapeutic use of shock waves or shock waves. More specifically, but not by way of limitation, the present disclosure relates to devices and methods for generating therapeutic shock waves or shock waves with improved acoustic wavefronts (shock waves with therapeutic use). [Background technology]

[0003] 2. Description of Related Art Acoustic shock waves have been used for certain treatments for several years. "Shock waves" or "shock waves" are generally used to refer to an acoustic phenomenon (e.g. resulting from an explosion or lightning) that produces a sudden and rapid change in pressure. These rapid pressure changes can produce powerful energy waves that can travel through elastic media such as air, water, human soft tissue, or certain solid materials such as bone, and / or induce inelastic responses in such elastic media. Methods for generating shock waves for therapeutic use include (1) electrohydraulic (EH) or spark gap, (2) electromagnetic or EMSE, and (3) piezoelectric. Each method is based on its own unique physical principle.

[0004] A. Devices and Systems for Generating Shockwaves US Patent Application No. 13 / 574,228, published as US 2014 / 0276722, by one of the present inventors, discloses a device for producing shock waves at high pulse rates using a transducer. The device includes an acoustic wave generator configured to emit acoustic waves having at least one frequency between 1 MHz and 1,000 MHz, a shockwave housing coupled to the acoustic wave generator, and a shockwave medium disposed within the shockwave housing, the apparatus configured such that when the acoustic wave generator emits acoustic waves, at least a portion of the acoustic waves will travel through the shockwave medium and form shockwaves. The device can be actuated to form shockwaves configured to rupture one or more cells of the patient into particles within the patient, and the shockwaves can be directed to the patient's cells such that the shockwaves rupture one or more of the cells into particles. The acoustic transducer device can produce high power shockwaves at high frequencies or pulse rates.

[0005] Additionally, U.S. Patent Application Serial No. 13 / 798,710, published as US 2014 / 0257144, also by the present inventors, discloses an apparatus and method for electrohydraulic generation of shockwaves at rates between 10 Hz and 5 MHz comprising a housing defining a chamber and a shockwave outlet, a liquid disposed within the chamber, a plurality of electrodes (e.g., in a spark head or module) disposed within the chamber and configured to define one or more spark gaps, and a pulse generation system configured to apply voltage pulses to the electrodes at rates between 10 Hz and 5 MHz.

[0006] Other systems for producing shockwaves can include electrohydraulic (EH) wave generators. EH systems can generally deliver similar levels of energy as other methods, but may be configured to deliver their energy over a larger area and therefore deliver a greater amount of shockwave energy to the target tissue over a shorter period of time. EH systems generally incorporate an electrode (i.e., a spark plug) to initiate the shockwave. In EH systems, high energy shockwaves are generated when electricity is applied to an electrode immersed in treated water contained within an enclosure. When the charge is fired, a small amount of water is vaporized at the tip of the electrode, and the rapid, near instantaneous expansion of the vaporized water creates a shockwave that propagates outward through the liquid water. In some embodiments, the water is contained within an ellipsoid enclosure. In these embodiments, the shockwaves can bounce off the sides of the ellipsoid enclosure and converge to a focal point that coincides with the location of the area to be treated.

[0007] For example, U.S. Patent No. 7,189,209 (the '209 patent) describes a method of treating pathological conditions associated with bone and musculoskeletal environments and soft tissues by applying acoustic shock waves. The '209 patent explains that the shock waves induce localized trauma, including microfractures, and cellular apoptosis therein, and induce osteogenic responses such as cell recruitment, stimulating the formation of molecular bone, cartilage, tendon, fascia, and soft tissue morphogens and growth factors, and inducing angiogenesis. The '209 patent claims several specific implementations of its method. For example, the '209 patent claims a method of treating diabetic foot ulcers or pressure sores, comprising locating a site or suspected site of diabetic foot ulcer or pressure sore in a human patient, generating acoustic shock waves, focusing the acoustic shock waves throughout the located site, and applying from 500 to about 2,500 or more acoustic shock waves per treatment to the located site to induce micro-damage and increased vascularization, thereby inducing or accelerating healing. The '209 patent discloses a frequency range of about 0.5 Hz to 4 Hz and application of about 300 to 2,500 or about 500 to 8,000 acoustic shock waves per treatment site, which may result in treatment durations per treatment site and / or "total time per treatment" for all sites that are inconveniently large. For example, the '209 patent discloses total time per treatment for different embodiments ranging from 20 minutes to 3 hours.

[0008] U.S. Patent No. 5,529,572 (the '572 patent) contains another example of the use of electrohydraulically generated shock waves to produce a therapeutic effect on tissue. The '572 patent describes a method of increasing bone density and strength (to treat osteoporosis) that includes subjecting the bone to generally planar collimated compressive shock waves having a substantially constant intensity as a function of distance from a shock wave source, the collimated shock waves being applied to the bone at an intensity of 50-500 atmospheres. The '572 patent describes the application of unfocused shock waves to produce dynamic, cyclic loading to the bone, increasing average bone density, thereby strengthening the bone against fracture. As explained in the '572 patent, "the unfocused shock waves are preferably applied at a frequency of, for example, 10-150 cm. 2 The shock waves are applied over a relatively large surface of the bone to be treated, covering an area of ​​​​100 mm. The intensity of the shock waves may be 50-500 atmospheres. Each shock wave is of a duration of a few microseconds, as in conventional lithotriptors, and is preferably applied at a frequency of 1-10 shock waves per second over a period of 5-30 minutes in each treatment. The number of treatments depends on the particular patient.

[0009] U.S. Patent Application Serial No. 10 / 415,293 (the '293 Application), also published as US 2004 / 0006288, discloses another embodiment of the use of EH generated shockwaves to provide a therapeutic effect to tissue. The '293 Application discloses devices, systems, and methods for the generation of therapeutic acoustic shockwaves to at least partially detach deposits from vascular structures. The '293 Application discloses a device that is capable of delivering shockwaves up to 1 cm 2 It has been described that shock waves can be produced at pulse repetition rates of about 50 to about 500 pulses per minute (i.e., 0.83 to 8.33 Hz) using pulse rates of about 100 to about 5,000 pulses per treatment site (per length of vascular unit being treated).

[0010] (B.Shockwave Rate) Prior art literature indicates that faster pulse rates using EH systems to deliver shock waves can lead to tissue damage. For example, in one study (Delius, Jordan, & et al, 1988)[1], the effects of shock waves on normal canine kidneys were examined in a group of dogs whose kidneys were exposed to 3,000 shock waves. The groups differed only in the shock wave administration rate, which was 100 Hz and 1 Hz, respectively. Necropsies were performed 24-30 hours later. Grossly and histologically, significantly more bleeding occurred in the renal parenchyma when shock waves were administered at a rate of 100 Hz (versus 1 Hz). Results showed that renal damage was dependent on the shock wave administration rate.

[0011] In another study (Madbouly & et al, 2005)[3], slower shockwave lithotripsy rates (SWL) were associated with a significantly higher success rate with fewer total shockwaves compared to faster shockwave lithotripsy rates. In this paper, the authors discussed how human studies also demonstrated a reduced incidence of SWL-induced renal injury or the need for anesthesia when slower test SWL rates were used.

[0012] Yet another study (Gillitzer & et al, 2009)[2] showed that slowing the delivery rate from 60 to 30 shockwaves per minute also provided dramatic protection to the integrity of the real vasculature in a porcine model. These findings support the potential strategy of reduced pulse repetition frequency to improve the safety and efficacy of extracorporeal shockwave lithotripsy.

[0013] Soft tissue may transition from elastic to viscous behavior for pulse repetition rates (PR) of 1 Hz to 10 Hz. As a result, potential damage to tissue from shockwaves at 1 Hz to 10 Hz PR is unpredictable when typical lithotripsy power levels are used. Perhaps as a result, the prior art teaches slower PR and many total times per treatment (TTPT). For example, currently known EH shockwave systems generally deliver PRs of less than 10 Hz and require many total times per treatment (e.g., TTPT periods of minutes or even hours even for a single treatment site). When a treatment requires repositioning of the device at multiple treatment sites, as may be typical, the TTPT becomes many and potentially impractical for many patients and treatment needs.

[0014] While long treatment times may be acceptable for extracorporeal shockwave lithotripsy, the use of shockwaves to provide non-lithotripsy therapeutic effects to tissues in a medical setting is suboptimal, if not impractical. For example, the cost of a treatment often increases with the time required to administer the treatment (e.g., due to the cost of labor, equipment, and other resources allocated to the administration of the treatment). Furthermore, in addition to the cost, at some point the duration of providing the treatment to a patient becomes unbearable for the patient receiving the treatment and the medical staff providing the treatment.

[0015] (C. Parabolic reflector) The use of a parabolic reflector allows for the generation of a plane wave that maintains peak pressure over a relatively long distance, and therefore has been beneficially used in deep tissue. However, parabolic reflectors can also present challenges.

[0016] First, when the tissue targeted for treatment is shallow (e.g., the dermis of the skin), the peak pressure of the plane wave persists beyond the targeted tissue when using a parabolic reflector. Such waves can result in unwanted damaging effects and pain at distant tissue sites beyond the targeted treatment site. For example, when treating the dermis, a relatively planar wave would sustain sufficient peak pressure to affect the underlying bone structures, resulting in significant pain to the patient. The formation of a sustained plane acoustic wave peak pressure produced by an electrohydraulic shockwave generator using a parabolic reflector is demonstrated by examining pressure maps of the acoustic wavefront at different tissue depths. For example, FIG. 1 depicts an acoustic wavefront pressure map from a shockwave generator using a standard parabolic reflector. As can be seen, the acoustic wavefront peak pressure map illustrates the sustained nature of the peak pressure. At a depth of 50 mm, the acoustic wavefront peak pressure is very high and essentially unchanged from the wavefront peak pressure at a depth of 30 mm.

[0017] Second, the plane acoustic waves generated through the use of a parabolic reflector in an electrohydraulic shockwave generator are often not uniform. Specifically, the parabolic reflector in an electrohydraulic shockwave generator can produce an acoustic wavefront that has both higher peak pressures (i.e., "hot spots") or lower peak pressures (i.e., "shadows"). This non-uniformity in the acoustic wavefront has at least two primary causes: (1) anomalous acoustic wave reflections generated within the chamber, and (2) instability in the electrode gap location within the chamber.

[0018] Aberrant acoustic wave reflections are typically caused by hardware found within the chamber (i.e., electrodes, electrode bridges, etc.), ports, edges, etc. These aberrant reflections will often result in the formation of acoustic wavefronts with higher peak pressures and areas of lower peak pressure.

[0019] Instability in the electrode gap location within the chamber results from a pair of electrodes producing a spark in the gap between the electrodes in an electrohydraulic shockwave generator. This electrical spark results in a plasma bubble that collapses to produce an acoustic wave. When the electrodes are placed at the proper focal location within the parabolic reflector, the reflected acoustic wave can result in the formation of a relatively planar wavefront. However, non-uniformity in the acoustic wavefront can occur when the focal location of the electrode gap ("f-location" or "focal location") changes. Erosion of the electrodes from the spark event leads to a change in the focal location of the spark event within the parabolic reflector. This instability in the focal location results in non-uniformity in the output acoustic wave. Figures 2A and 2B depict graphical representations of pressure lines emanating from a parabolic reflector 202 showing the effect of various electrode gap focal locations 200. In Figure 2A, the focal location of the electrode gap 200 is at f=0.93, resulting in pressure lines that converge at the center. This convergence of these pressure lines will result in peak pressure hot spots 204 deeper within the tissue, resulting in excessive tissue damage, procedural discomfort, and pain. Similarly, in Figure 2B, the focal location of the electrode gap 200 is at f=0.6, resulting in pressure lines converging around the circumference of the treatment area. The convergence of pressure lines around the circumference of the treatment area will result in peak pressure hot spots 204 deeper within the tissue, resulting in excessive tissue damage, procedural discomfort, and pain.

[0020] Thus, while the use of parabolic reflectors may produce stable acoustic waves in selected treatment situations, prior art approaches are not optimal in consistently providing a uniform acoustic wavefront due to acoustic wave peak pressure persistence and acoustic wave non-uniformity (i.e., hot spots and shadows). As a result, these acoustic wavefront persistence and hot spots can result in treatments that are both painful and harmful to the patient.

[0021] (D. Free form reflector) A freeform reflector is a reflector that is not purely parabolic. In the lighting field, freeform reflectors on light sources are used to help provide uniform circular illumination. Due to their high design freedom, freeform surfaces can simplify the construction of optical systems and meet complex lighting requirements. With the development of design and machining of freeform surfaces in the past few years, this technique has been applied in many fields such as road or search lighting, lighting in projectors, liquid crystal display (LCD) backlighting, automotive headlamps, and optical lithography systems, among others (Liu & et al, 2005) [4]. Designing freeform reflectors for lighting is challenging. In recent years, several approaches have been described [4]. These approaches are believed to utilize special algorithms and optimization techniques that are specific to the use of light. Examples of freeform reflectors for optical output can be found in: (1) U.S. Pat. No. 5,790,305, (2) U.S. Patent Application Publication No. US 2010 / 0208467, (3) U.S. Pat. No. 5,675,495, and (4) U.S. Pat. No. 5,204,820. [Prior art documents] [Patent documents]

[0022] [Patent Document 1] US Patent Application Publication No. 2014 / 0276722 [Patent Document 2] US Patent Application Publication No. 2014 / 0257144 [Patent Document 3] U.S. Pat. No. 7,189,209 [Patent Document 4] U.S. Pat. No. 5,529,572 [Patent Document 5] US Patent Application Publication No. 2004 / 0006288 Summary of the Invention [Means for solving the problem]

[0023] The present disclosure includes embodiments of devices and methods for electrohydraulic generation of fast acoustic pulses with improved acoustic wavefronts. In certain embodiments, these improved acoustic wavefronts comprise essentially planar acoustic wavefronts in the field near the targeted treatment area that disperse rapidly after a defined distance. Such wavefronts provide effective acoustic therapy within the targeted area while limiting tissue damage and pain beyond the targeted area. In another embodiment, the improved acoustic wavefronts comprise essentially planar unfocused acoustic wavefronts in the field near the targeted treatment area that disperse rapidly after a defined distance, where the acoustic wavefront is essentially uniform in terms of peak pressure. Such wavefronts provide effective acoustic therapy within the targeted area that minimizes high concentrations of peak pressure (i.e., "hot spots") and low concentrations of peak pressure (i.e., "shadows"). These essentially uniform unfocused acoustic wavefronts provide more consistent therapy across the targeted treatment area.

[0024] In an embodiment, an apparatus for electrohydraulic generation of acoustic waves comprises a housing defining a chamber and a shockwave outlet, a liquid disposed within the chamber, an acoustic reflector within the chamber, a plurality of electrodes (e.g., in a spark head or module) disposed within the chamber and configured to define one or more spark gaps, and a pulse generation system configured to apply voltage pulses to the electrodes at a rate between 10 Hz and 5 MHz. In one embodiment, an improved acoustic wavefront is achieved using an acoustic reflector within the chamber. In another embodiment, an improved acoustic wavefront is achieved using an acoustic freeform reflector within the chamber. In yet another embodiment, an improved acoustic wavefront is achieved by providing a stable spark gap location within the chamber. In yet another embodiment, an improved acoustic wavefront is achieved through the use of an acoustic freeform reflector and a stable spark gap location within the chamber.

[0025] Some embodiments of the present device (e.g., for generating therapeutic acoustic waves) include a housing defining a chamber and a shockwave outlet, a chamber configured to receive a liquid, a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps, an acoustic reflector disposed within the chamber, and a single servo motor mechanically coupled to the plurality of electrodes, the spark gap having a spark gap size and a spark gap location, and the single servo motor configured to adjust each of the electrodes to maintain a consistent spark gap size and spark gap location. In some embodiments, the acoustic reflector is a freeform acoustic reflector. In some embodiments, the plurality of electrodes includes a first electrode and a second electrode, and the single servo motor is mechanically coupled to the first electrode and the second electrode. Some embodiments further include a plurality of pivot arms mechanically coupled to the second electrode. In some embodiments, the plurality of pivot arms are configured to advance the second electrode toward the first electrode when the single servo motor is actuated. Some embodiments further comprise a controller configured to signal the single servo motor via closed loop control to move the multiple electrodes and maintain the spark gap at a consistent length. In some embodiments, the controller is further configured to signal the single servo motor via closed loop control by measuring a pulse time of the discharge of the multiple electrodes at the identified charge voltage and signaling the single servo motor to move based on the measured pulse time, thereby maintaining the spark gap at a consistent length. Some embodiments further comprise a pulse generation system, where (i) the housing is moveable relative to the pulse generation system and (ii) the pulse generation system is configured to be coupled to the multiple electrodes such that the pulse generation system is in electrical communication with the multiple electrodes.

[0026] Some embodiments of the present devices (e.g., for generating therapeutic acoustic waves) include a housing defining a chamber and a shockwave outlet, a liquid disposed within the chamber, a housing defining the chamber and the shockwave outlet, the chamber configured to receive the liquid, a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps, and a freeform acoustic reflector disposed within the chamber, the spark gap having a spark gap size and a spark gap location. In some embodiments, the acoustic reflector is integral with the housing.

[0027] Some embodiments of the method (e.g., for designing a freeform acoustic reflector) include the steps of defining an origin of an acoustic pulse, a target treatment area of ​​a patient, and a safety depth, iterating the reflector shape until a reflector shape capable of providing an energy distribution consistent with the specified target treatment area and safety depth is achieved, approximating an energy density based on the final reflector shape, and validating the final reflector shape. In some embodiments, the step of defining an origin of an acoustic pulse further includes defining where a plurality of electrodes are located within an electrohydraulic acoustic wave generator. In some embodiments, the step of defining a target treatment area of ​​a patient further includes specifying a tissue depth to deliver a uniform pressure density. In some embodiments, the step of defining a safety depth further includes determining a depth within the patient's tissue where unfocused acoustic waves dissipate by 50 percent. In some embodiments, the step of iterating the reflector shape further includes using spline interpolation. In some embodiments, the step of approximating the energy density further includes performing ray tracing. In some embodiments, the step of validating the final reflector shape further includes using a finite element method (FEM) simulation.

[0028] The term "coupled" is defined as connected, not necessarily directly, and not necessarily mechanically, i.e., two items that are "coupled" may be integral to one another. The terms "a" and "an" are defined as one or more, unless this disclosure expressly requires otherwise. The term "approximately" is defined as largely, but not necessarily entirely, what is defined (and includes what is defined, e.g., approximately 90 degrees includes 90 degrees, approximately parallel includes parallel), as will be understood by those of skill in the art. In any disclosed embodiment, the terms "approximately," "approximately," and "about" may be substituted with "within [a percentage] of" what is defined, with percentages including 0.1, 1, 5, and 10 percent. In a disclosed embodiment, the term "adjacent" is defined as generally located within the same discrete chamber, housing, or module.

[0029] The terms "comprise" (and any form of comprise, such as "comprises" and "comprising"), "have" (and any form of have, such as "has" and "having"), "include" (and any form of include, such as "includes" and "including"), and "contain" (and any form of contain, such as "contains" and "containing") are open-ended linking verbs. As a result, a system or device that "comprises," "has," "includes," or "contains" one or more elements may possess those one or more elements, but is not limited to possessing only those elements. Similarly, a method that "comprises," "has," "includes," or "contains" one or more steps may possess those one or more steps, but is not limited to possessing only those one or more steps.

[0030] Furthermore, a structure (eg, a component of an apparatus) that is configured in a certain manner is configured in at least that manner, but it may also be configured in ways other than those specifically described.

[0031] Any embodiment of any of the present systems, apparatus, and methods can consist of, or consist essentially of, any of the described steps, elements, and / or features. Thus, in any of the claims, the terms "consisting of" or "consisting essentially of" can be substituted for any of the open-ended linking verbs listed above to modify the scope of a given claim from what would otherwise be the case using the open-ended linking verb.

[0032] Details relating to the above-described embodiments and others are provided below. The present invention provides, for example, the following items. (Item 1) 1. A device for generating therapeutic acoustic waves, comprising: a housing defining a chamber and a shockwave outlet, the chamber configured to receive a liquid; a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps; an acoustic reflector disposed within the chamber; a single servo motor mechanically coupled to the plurality of electrodes; Equipped with each of the spark gaps has a spark gap size and a spark gap location; The apparatus, wherein the single servo motor is configured to adjust each electrode of the plurality of electrodes to maintain a consistent spark gap size and spark gap location. (Item 2) Item 1, wherein the acoustic reflector comprises a freeform acoustic reflector. (Item 3) the plurality of electrodes includes a first electrode and a second electrode; 2. The apparatus of claim 1, wherein the single servo motor is mechanically coupled to the first electrode and the second electrode. (Item 4) Item 4. The apparatus of item 3, further comprising a plurality of pivot arms mechanically coupled to the second electrode. (Item 5) 5. The apparatus of claim 4, wherein the plurality of pivot arms are configured to advance the second electrode toward the first electrode in response to the single servo motor being actuated. (Item 6) 2. The apparatus of claim 1, further comprising a controller, the controller configured to operate to move the multiple electrodes and maintain the spark gap at a consistent length by signaling the single servo motor via closed loop control. (Item 7) The controller is further configured to signal the single servo motor via the closed loop control, and to signal the single servo motor, the controller comprises: measuring a pulse time of discharge of the plurality of electrodes at the identified charging voltage; signaling said single servo motor to move based on said measured pulse time, thereby maintaining said spark gap at a consistent length; 7. The apparatus of item 6, configured to perform the steps of: (Item 8) 1. A pulse-generation system, the pulse-generation system being configured such that (i) the housing is movable relative to the pulse-generation system, and (ii) the pulse-generation system is coupled to a plurality of electrodes such that the pulse-generation system is in electrical communication with the plurality of electrodes. Item 1. The apparatus of item 1, further comprising: (Item 9) 1. A device for generating therapeutic acoustic waves, comprising: a housing defining a chamber and a shockwave outlet, the chamber configured to receive a liquid; a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps; a freeform acoustic reflector disposed within the chamber; Equipped with wherein each of the one or more spark gaps has a spark gap size and a spark gap location. (Item 10) 10. The apparatus of claim 9, wherein the acoustic reflector is integral with the housing. (Item 11) 1. A method for designing a freeform acoustic reflector, comprising: Defining an origin of an acoustic pulse, a target treatment area of ​​a patient, and a safety depth; iterating through reflector shapes until a reflector shape is achieved that can provide an energy distribution consistent with the defined target treatment area and the defined safety depth; Estimating an energy density based on a final reflector shape; Verifying the final reflector shape. A method comprising: (Item 12) 12. The method of claim 11, wherein defining an origin of the acoustic pulse further comprises defining where a plurality of electrodes are located within an electrical hydraulic acoustic wave generator. (Item 13) 12. The method of claim 11, wherein defining the target treatment area of ​​the patient further comprises specifying a tissue depth to which the uniform pressure density is delivered. (Item 14) 12. The method of claim 11, wherein defining a safe depth further comprises determining a depth within the patient's tissue at which unfocused acoustic waves dissipate by 50 percent. (Item 15) Item 12. The method of item 11, wherein iterating the reflector shape further includes using spline interpolation. (Item 16) Item 12. The method of item 11, wherein estimating the energy density further comprises performing ray tracing. (Item 17) Item 12. The method of item 11, wherein verifying the final reflector shape further comprises using a finite element method (FEM) simulation. [Brief description of the drawings]

[0033] The following drawings are illustrated by way of example, not limitation. For simplicity and clarity, not all features of a given structure are necessarily labeled in every figure in which the structure appears. The same reference numbers do not necessarily refer to the same structures. Rather, the same reference numbers may be used to refer to similar features or features with similar functionality, which may be non-identical reference numbers. The figures are drawn to scale (unless otherwise noted), meaning that the sizes of the depicted elements are accurate relative to one another, at least with respect to the embodiments depicted in the figures.

[0034] [Figure 1] FIG. 1 depicts an acoustic wavefront pressure map from a prior art shockwave generator using a standard parabolic reflector.

[0035] [Figure 2A] 2A and 2B depict a graphical representation of pressure lines emanating from a parabolic reflector. [Figure 2B] 2A and 2B depict a graphical representation of pressure lines emanating from a parabolic reflector.

[0036] [Diagram 3] FIG. 3 depicts a flow chart for an optimization process for designing a freeform acoustic reflector having a defined acoustic wavefront.

[0037] [Figure 4] FIG. 4 depicts a graphical representation of the ray tracing of acoustic waves reflected from a freeform reflector.

[0038] [Diagram 5] FIG. 5 depicts the FEM simulation of a freeform reflector designed using spline interpolation.

[0039] [Figure 6A] 6A and 6B depict isometric and cross-sectional views, respectively, of the spark head portion of the device. [Figure 6B] 6A and 6B depict isometric and cross-sectional views, respectively, of the spark head portion of the device.

[0040] [Figure 7] FIG. 7 is an acoustic wavefront pressure map from a prior art shockwave generator using a standard parabolic reflector.

[0041] [Figure 8] FIG. 8 is a side-by-side comparison of acoustic wavefront pressure maps of a parabolic reflector and a freeform reflector.

[0042] [Figure 9] FIG. 9 is a graph providing experimental data regarding the ratio of cathodic and anodic electrode erosion rates.

[0043] [Figure 10] FIG. 10 depicts a cross-sectional view of one embodiment of an apparatus for electrohydraulic generation of acoustic waves having an improved acoustic wavefront.

[0044] [Figure 11] FIG. 11 depicts a perspective view of certain components of the apparatus of FIG.

[0045] [Figure 12A] 12A-12C depict three views illustrating the function of the components of FIG. [Figure 12B] 12A-12C depict three views illustrating the function of the components of FIG. [Figure 12C] 12A-12C depict three views illustrating the function of the components of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Certain embodiments of the present systems and devices are configured to generate high frequency shock waves with improved acoustic wavefronts. In some embodiments, the generated EH acoustic pulses can be used in medical and / or aesthetic treatment applications (e.g., when directed and / or delivered to a target tissue of a patient). Examples of medical and / or aesthetic treatment applications in which the present systems can be used are disclosed in (1) U.S. Patent Application No. 13 / 574,228, published as US 2013 / 0046207, (2) U.S. Patent Application No. 13 / 547,995, published as US 2013 / 0018287, and (3) U.S. Patent Application No. 13 / 798,710, published as US 2014 / 0257144, each of which is incorporated herein in its entirety.

[0047] In one embodiment, an apparatus for electrohydraulic generation of shockwaves includes a housing defining a chamber and a shockwave outlet, a liquid disposed within the chamber, a plurality of electrodes (e.g., in a spark head or module) disposed within the chamber and configured to define one or more spark gaps, and a pulse generation system configured to apply voltage pulses to the electrodes at a rate between 10 Hz and 5 MHz. The rate of the voltage pulses may be at rates of 25Hz, 50Hz, 75Hz, 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 400Hz, 500Hz, 600Hz, 700Hz, 800Hz, 900Hz, 1KHz, 5KHz, 10KHz, 25KHz, 50KHz, 100KHz, 200KHz, 300KHz, 400KHz, 500KHz, 600KHz, 700KHz, 800KHz, 900KHz, 1MHz, 2MHz, 3MHz, and 4MHz, as illustrative non-limiting examples.

[0048] In some embodiments, the pulse generation system is configured to produce a series of acoustic shockwaves with an improved acoustic wavefront. The improved acoustic wavefront includes an essentially planar acoustic wavefront in the field near the targeted treatment area that disperses quickly after a defined distance. Such a wavefront provides effective acoustic therapy within the targeted treatment area but limits tissue damage and pain beyond the targeted area. In some embodiments, the improved acoustic wavefront includes an essentially planar unfocused acoustic wavefront in the field near the targeted treatment area that disperses quickly after a defined distance, where the acoustic wavefront is essentially uniform in terms of peak pressure. Such a wavefront allows for effective acoustic therapy within the targeted area that minimizes high concentrations of peak pressure (i.e., "hot spots") and low concentrations of peak pressure (i.e., "shadows"). Having an essentially uniform unfocused acoustic wavefront provides a more consistent treatment across the targeted treatment area.

[0049] In certain embodiments, an improved acoustic waveform (e.g., acoustic wavefront) is achieved using an acoustic reflector in the chamber. More specifically, certain embodiments use a freeform acoustic reflector to achieve the desired wavefront. In still further embodiments, an improved acoustic wavefront is achieved by providing a stable spark gap location in the chamber. A stabilized acoustic wavefront is achieved by maintaining a spark gap formed from multiple electrodes at a constant focal location in the chamber. In one embodiment, the multiple electrodes are automatically adjusted via a focal stabilization unit that includes a single servo motor that is used to maintain the spark gap at a constant focal location in the chamber. Certain embodiments of the disclosed apparatus include both a freeform acoustic reflector and a focal stabilization unit.

[0050] (A. Free-form reflector) Although freeform reflectors have been used for lighting purposes, using freeform reflectors for acoustic output is difficult and impractical. For example, light waves are significantly smaller than acoustic waves, and therefore current approaches for designing optical freeform reflectors would be even more difficult when used for longer wave acoustic output. In addition, unlike light sources such as filament lamps or LEDs, acoustic sources are typically large (e.g., not necessarily "point sources"), making the design of freeform non-planar acoustic reflectors even more difficult.

[0051] Current approaches to electrohydraulic generation of acoustic waves using parabolic reflectors are suboptimal in some cases. For example, parabolic reflectors may not mitigate acoustic wave non-uniformity, thereby resulting in hot spots and shadows. As discussed above, the two main causes of acoustic wave non-uniformity are (1) anomalous acoustic wave reflections generated within the chamber and (2) the varying focal location of the electrode gap ("f-location").

[0052] Aberrant reflections are typically caused by hardware (i.e., electrodes, electrode bridges, etc.), ports, edges, etc. found within the chamber. These aberrant acoustic wave reflections will result in the formation of acoustic wavefronts with areas of higher and lower peak pressure. Changes in the focal location of the electrode gap can result from erosion of the electrodes caused from spark events.

[0053] In practice, acoustic wavefront non-uniformity can be problematic. Both anomalous acoustic waves and varying electrode gap locations cause wavefront focusing and divergence within the treatment area resulting in areas of high pressure (hot spots) and low pressure (shadows). These acoustic wavefront hot spots can lead to localized areas of high pressure both within and outside the target treatment area, resulting in tissue damage and / or pain. Acoustic wavefront shadows cause areas of sub-therapeutic acoustic wave delivery.

[0054] As discussed above, freeform reflectors are currently used to alleviate similar problems in the fields of illumination and optics. However, as also discussed above, using freeform reflectors for acoustic output is currently difficult and impractical due to the inherent differences between light and acoustic waves. Despite these challenges, according to some embodiments of the present invention, freeform reflectors can be designed to provide improved acoustic wavefront output uniformity at a defined treatment depth while minimizing acoustic wave persistence at deeper depths. These freeform reflectors are designed to minimize acoustic hot spots while taking into account structures located within the chamber (i.e., electrodes, electrode bridges, water ports, chamber edges, etc.).

[0055] Referring now to the drawings, Figure 3 depicts an optimization process for designing a freeform acoustic reflector having a defined acoustic wavefront. As an example, a freeform acoustic reflector can be designed and / or improved (e.g., optimized) using spline interpolation. The process of Figure 3 may be computer-implemented, such as by a processor coupled to a memory and configured to execute instructions stored in the memory to cause the processor to perform operations to perform the process of Figure 3.

[0056] In the embodiment shown, the optimization process for designing a freeform acoustic reflector with a defined wavefront includes steps: (1) defining the origin of the acoustic pulse 300; (2) defining the treatment area 302; (3) defining a safety depth 304; (4) iterating the reflector shape using spline interpolation 306 until the desired shape is achieved; (5) performing ray tracing to estimate the energy density 308; and (6) validating the resulting structure using finite element method (FEM) simulation 310.

[0057] In the embodiment shown, an origin 300 of the acoustic pulse is identified or defined. For example, the origin of the acoustic pulse is typically at or between the electrodes that define one or more spark gaps in the chamber of an electrohydraulic acoustic wave generator. In such electrohydraulic generators, opposing electrodes are often used to generate the pulse. When the electrodes have flat faces, the origin of the acoustic pulse is typically at the edge of the electrodes, not their center. This is true regardless of the location of the discharge event, since in many cases the acoustic waves will bounce back and forth between the parallel electrode faces until they reach the edge. In other embodiments, the origin of the acoustic pulse may be at the electromagnetic acoustic wave generator or the piezoelectric acoustic wave generator.

[0058] In the embodiment shown, the target treatment area 302 is then defined or defined, including defining the tissue depth where a uniform pressure density is desired. For example, in the context of treating a tattoo, the target treatment area 400 to have a uniform pressure density is less than 2 mm deep (e.g., from the surface of the patient's skin). In other contexts, the target treatment area to have a uniform pressure area may be 1 mm, 3 mm, 4 mm, 5 mm, or 1 cm deep from the surface of the patient's skin.

[0059] Next, according to an embodiment, a safe depth 304 within the patient's tissue is defined. The safe depth is the point or depth at which the unfocused acoustic waves need to dissipate in half to minimize tissue damage and pain to the patient. This safe depth 402 is defined relative to the surface of the patient's skin based on factors specific to the patient's target area. For example, when treating skin covering an area with 1 cm or more of muscle or other soft tissue between the treated skin and the underlying bone tissue, the safe depth may be 5 mm. In some embodiments, the safe depth 402 may be defined as a percentage of the target depth 400, such as, for example, equal to or greater than any one of, or between any two of, 200%, 250%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, 1,000%, or more of the target depth.

[0060] In the illustrated embodiment, after the safe depths are identified or otherwise defined, the reflector shape is modified using spline interpolation 306 to achieve a desired (e.g., substantially uniform) energy distribution. Spline interpolation refers to a form of interpolation in which the interpolation equation is a piecewise polynomial called a spline. Iterating using spline interpolation in three dimensions allows the reflector shape to be defined by solving an "inverse problem" while compensating for obstacles in the reflector. Specific spline interpolation requirements, such as continuity of curvature and no curvature inflection points, are used as input conditions.

[0061] In one example, the spline interpolation step produced a freeform reflector shape defined by the following equation (using inches as the unit of measurement): y=0.236x 3 +0.2948x 2 +0.1141x-0.3689 In another embodiment, a spline interpolation step produced a freeform reflector shape defined by the following equation (using millimeters as the unit of measurement): y=0.0004x 3 +0.0116x 2 +0.1141x-9.3707

[0062] In the illustrated embodiment, after the reflector shape is defined, ray tracing 308 is used to estimate the energy density that will be reflected by the reflector. Traditionally, ray tracing refers to a technique for generating an image by tracing the path of light and simulating the effect of its encounter with a virtual object. Here, as depicted in FIG. 4, ray tracing can be performed to estimate the energy density from the defined reflector shape by spline interpolation. In FIG. 4, acoustic waves (depicted as vectors 404) are generated in the electrode gap 200 and reflected from a freeform reflector 406. These acoustic waves ideally have a uniform pressure density once they reach the target tissue depth 400 and are dissipated by at least a factor of two by the time they reach the safety depth 402. In FIG. 4, the waves 404 are approximately uniformly spaced at the target tissue depth 400 and exhibit an approximately uniform energy distribution across the reflector profile. However, at the safety depth 402, the rays are further apart (e.g., have a substantially non-uniform energy distribution) and exhibit a lower energy density. Although a uniform pressure density at the target tissue depth is ideal, peak pressure variations of 1, 3, 5, or 10 percent above other peak pressure readings from the generated waves and then the freeform reflector may also perform the desired therapeutic function with limited or no adverse effects.

[0063] In the embodiment shown, the resulting reflector shape can be modeled (310), for example, using an acoustic finite element method (FEM) simulation. FEM refers to a numerical technique for finding approximate solutions to boundary value problems. FIG. 5 depicts an FEM simulation of a freeform reflector designed using the process of spline interpolation described above. If the FEM simulation determines that the freeform acoustic reflector is viable, a physical prototype can then be fabricated and physically tested, if desired.

[0064] 6A and 6B depict an embodiment of a therapeutic wave generator. FIG 6A depicts an isometric view of the spark head portion of the disclosed therapeutic wave generator comprising a freeform reflector 406. Additionally, FIG 6B depicts a cross section of the spark head portion of one embodiment of a therapeutic wave generator comprising a freeform reflector 406.

[0065] 7 depicts an acoustic wavefront pressure map produced from a shockwave generator using a freeform reflector designed based on the general optimization process described above. The acoustic map demonstrates that the acoustic wavefront peak pressure is limited to a shallow depth in the dermis (approximately 2 mm), thereby demonstrating a substantial improvement over a parabolic reflector as shown in FIG. 1, where the acoustic wavefront peak pressure is still persistent at a depth of 50 mm.

[0066] FIG. 8 depicts a comparison of the acoustic map of a parabolic reflector (800, FIG. 1) with that of a freeform reflector (802, FIG. 7). As shown in FIG. 8, the use of a freeform reflector provides a means for minimizing acoustic pressure hot spots when compared to those produced using a parabolic reflector. The parabolic reflector portion 800 of FIG. 8 demonstrates circumferential hot spots 804 that persist to deep tissue depths. These acoustic hot spots can result in tissue damage and procedural discomfort. Differently, the acoustic map of the freeform reflector 802 shows the effective elimination 806 of circumferential hot spots at the depths achieved by the use of the freeform reflector design. Thus, a procedure using a freeform reflector provides a less painful procedure with less potential for collateral tissue damage.

[0067] (B. Focus stabilization) The discussion of acoustic wavefront shaping generated by an electrohydraulic generator was published on July 21, 2016 in a patent application entitled "Rapid Pulse Electrohydraulic (EH) No. 62 / 365,009, entitled "Shockwave Generator Apparatus With Improved Electrode Life," which is incorporated by reference in its entirety.

[0068] The use of freeform acoustic reflectors to provide an improved acoustic wavefront can help provide an effective painless treatment. However, the design of such freeform reflectors can be optimized with a stable focal location of the acoustic source within the chamber. Prior art acoustic wave generators are suboptimal in providing a stable focal location, which can lead to difficulties in designing freeform reflectors for acoustic applications.

[0069] In order to maintain a stable acoustic focal location within the chamber, not only does the specific electrode gap size need to be maintained, but the specific electrode gap location within the reflector chamber should also remain constant. Maintaining a stable gap size and gap location within the chamber is difficult because the electrodes erode at different rates. To overcome this problem, each electrode must be adjusted periodically.

[0070] Manual adjustment of one or both of the electrodes is one potential solution to adjusting the acoustic focal location and electrode gap size. Such manual approaches may involve, for example, moving the electrodes via a screw-like mechanism. While these manual approaches may be acceptable for electrohydraulic shockwave generators that produce acoustic pulses at a very slow rate, electrohydraulic shockwave generators that rapidly produce multiple pulses may rapidly erode the electrodes and thus require near-constant adjustment, a requirement that is difficult to meet with manual adjustment of the electrodes.

[0071] In addition, to maintain a stable gap location within the chamber, any adjustment method should not only maintain a specific gap size between the electrodes, but also maintain a specific gap location within the housing. If the electrode size is kept stable but the gap location within the chamber shifts, the resulting acoustic wavefront will not be stable. As a result, adjustment of both electrodes is required to maintain both the gap size and the gap location (i.e., the focal location within the chamber). It is difficult and impractical to achieve this in a commercially viable manner using manual adjustment of both electrodes.

[0072] Therefore, an automated electrode adjustment method would be useful in providing a stable electrode gap size and location within the chamber. One example of a conventional automated electrode adjustment approach for maintaining a specific electrode gap size and gap location within the chamber is described in U.S. Patent Application Serial No. 10 / 896,040 (the '040 Application), also published as US 2006 / 0036168. The '040 Application describes an electrohydraulic shockwave generation system with automatic gap adjustment, in which the gap control unit includes two servo motors and two servo motor drivers for driving the servo motors. Two servo motors are used in the system of the '040 Application because each electrode erodes at a different rate. Therefore, in order to maintain a specific gap location, each electrode needs to be adjusted a different amount to maintain the electrode gap size and gap location.

[0073] The use of two servo motors to maintain the electrode gap location within the reflector adds cost and engineering design complexity to the electrohydraulic device containing the electrodes. As a result, it has been impractical to build a low-cost, commercially viable electrohydraulic shockwave generating system that includes a simple acoustic head with an automated adjustable electrode. Building one that is disposable has also been impractical and commercially unsuitable.

[0074] Although the two electrodes used in an electrohydraulic acoustic wave generator may erode at different rates, their erosion rates should be relatively similar at a defined power level, and the ratio of the erosion rates should be relatively similar at a defined power level. FIG. 9 depicts the experimental results of running several different electrohydraulic generators for a period of time at a power level of 325 nF, after which the erosion for each separate electrode was measured. The results show that in every trial, both electrodes underwent erosion, and both electrodes in an electrode pair underwent different rates of erosion. In addition, the results show that the erosion rates for both electrodes in each electrode pair were relatively constant, as was the ratio of the erosion rates for the two electrodes. As shown in FIG. 9, the average wear rate was 2.62.

[0075] Based on these results, adjustment of both electrodes can now be accomplished using a single servo motor (and appropriate gearing) to maintain a specific gap size and focal location within the electrohydraulic generator chamber. This simplifies the design and cost to make a commercially viable electrohydraulic generator and allows for the production of simple, inexpensive, disposable electrohydraulic heads with automated adjustment electrodes.

[0076] (Example) FIG. 10 depicts a cross-sectional view of one embodiment of an apparatus for electrohydraulic generation of acoustic waves with improved acoustic wavefronts. As shown in FIG. 10, the apparatus 1000 for electrohydraulic generation of acoustic waves comprises a housing 1004 defining a chamber 1008 and a shockwave outlet 1012, a liquid disposed within the chamber 1008, an acoustic reflector 1020 within the chamber 1008, a plurality of electrodes 1016a, 1016b (e.g., in a spark head or module) disposed within the chamber 1008 and configured to define one or more spark gaps 200, and a pulse generation system configured to apply voltage pulses to the electrodes 1016a, 1016b at a rate between 10 Hz and 5 MHz. In the embodiment shown, the acoustic reflector 1020 is or comprises a freeform reflector, while in other embodiments, the acoustic reflector may be parabolic.

[0077] In this embodiment, a stabilized acoustic wavefront is achieved using a freeform acoustic reflector having a spark gap formed from multiple electrodes that is maintained at a constant focal location from the acoustic reflector.

[0078] In some of the embodiments, the spark gap between multiple (e.g., two) electrodes is automatically adjusted using a single servo motor to maintain the spark gap at a substantially constant focal location from the reflector. For example, in the embodiment shown in Figures 10-12, a single servo motor is used to move the pair of electrodes such that the size and location of the electrode gap is maintained substantially constant. Figure 10 depicts a perspective cross-sectional view of a portion of an apparatus or probe 1000 that may be connected to a power source to electrohydraulically generate shock waves, Figure 11 depicts a perspective view of components of probe 1000 that allow adjustment of the electrodes to maintain the size and location of the spark gap, and Figures 12A-12C depict the components of Figure 11 in three different positions illustrating the maintenance of the spark gap.

[0079] In the embodiment shown, the device 1000 includes a housing 1004 that defines a chamber 1008 and a shockwave outlet 1012, the chamber configured to receive (e.g., be filled with) a liquid, such as water. As shown, the device 1000 also includes a plurality of electrodes 1016a, 1016b disposed within (e.g., defining a portion of a boundary of) the chamber 1008, and an acoustic reflector 1020. As shown, the electrodes 1016 are disposed within the chamber 1008 and configured to define one or more spark gaps 200 having a size (i.e., distance between end faces of the electrodes 1016a and 1016b) and a location. In the embodiment shown, the reflector 1020 is a freeform reflector.

[0080] In the embodiment shown, the apparatus 1000 comprises a single servo motor 1024 mechanically coupled to the multiple electrodes 1016a, 1016b and configured to adjust each of the electrodes to maintain the size and location of the spark gap 200 substantially constant. In this embodiment, the servo motor 1024 has an output shaft 1028 with a chuck or coupler 1032 that couples the shaft 1028 to a lead screw 1036 that is coupled via a screw thread to a shuttle or pusher 1040 such that rotation of the lead screw 1036 effects longitudinal movement of the pusher 1040. The primary electrode 1016a is coupled to (e.g., configured to be pushed by) the pusher 1040; for example, in the embodiment shown, a primary electrode carrier 1044 extends to / carries the primary electrode 1016a and extends to the pusher 1040 as shown. In other embodiments, the electrode carrier 1044 and the primary electrode 116a may be unitary (e.g., formed from a single piece of material). As shown, a spreader bar 1048 is coupled to the primary electrode carrier 1044 in a fixed relationship, and the spreader bar 1048 carries two pusher rods 1052a, 1052b extending therefrom and configured to interact with two respective pivot arms 1056a, 1056b. As shown, the pivot arms 1056a, 1056b are pivotally coupled (e.g., via pins) to the housing 1004 at respective pivot points 1060a, 1060b, respectively, such that the pusher rods 1052a, 1052b advance in a direction 1064.

[0081] In this embodiment, the secondary electrode 1016b is coupled to (and carried by) the secondary electrode carrier 1064. As shown, the secondary electrode carrier 1064 has an inverted U-shape and is slidably coupled to the housing 1004 (e.g., slidably disposed within a slot or track 1068). In addition, a spring or other biasing member (not shown) biases the secondary carrier 1064 and secondary electrode 1016b in a direction 1072 away from the primary electrode 1016a.

[0082] 12A-12C, when the motor 1024 is actuated, the shaft 1028 rotates the lead screw 1036, which in turn advances the shuttle 1040, the primary electrode carrier 1044, the primary electrode 1016a, the spreader bar 1048, and the pusher rods 1052a, 1052b longitudinally in the direction 1072. As these components advance, the pusher rods 1052a, 1052b contact and impart a force in the direction 1072 to the respective first ends 1076a, 1076b of the pivot arms 1056a, 1056b. An upward force on the first ends 1076a, 1076b (in the orientation depicted in FIGS. 12A-12C) causes the pivot arms 1056a, 1056b to pivot about their respective pivot points 1060a, 1060b, moving the respective second ends 1080a, 1080b of the pivot arms downward, imparting a force in the direction 1084 to the secondary electrode carrier 1064, moving the secondary electrode 1016b towards the primary electrode 1016a. In this manner, a single servo motor can simultaneously move the primary electrode 1016a upward and the secondary electrode 1016b downward, maintaining both the size and position of the electrode gap between the ends of the electrodes 1016a, 1016b as the electrodes erode during use.

[0083] In the embodiment shown, the housing 1004 also houses a circuit board assembly 1100 configured to receive voltage from an external pulse generation system (not shown) and deliver a voltage pulse to and / or through the primary electrodes 1016a to generate a spark between the electrodes, thereby generating a shockwave, as described in U.S. Provisional Patent Application No. 62 / 365,009 (incorporated above). In the embodiment shown, a controller 1104 is coupled in electrical communication with one or both of the electrodes via connection 1108 (e.g., via the circuit board assembly 1100 as shown, or in other embodiments, directly) and with the motor 1024 via connection 1112, such that the controller may control the motor 1024 based on measurements of the spark between the electrodes. For example, to maintain a constant electrode gap size and location, a closed loop control is used to signal the motor 1124 to feed the electrodes forward and maintain the gap 200 at the desired size. This closed loop control may be implemented by measuring the pulse time of the discharge at a particular charge voltage. The characteristics of the discharge are very closely correlated with the distance of the electrode gap 200. By measuring these characteristics, closed loop control can be implemented by signaling the motor 1024 to move, thereby maintaining the gap between the electrodes, and thus maintaining the desired electrical characteristics of the discharge. In some embodiments, the controller 1104 is a component of the spark generation system (e.g., the functionality described with respect to the controller 1104 is incorporated into instructions or code executed by a primary discharge controller of the spark generation system). For example, the motor 1024 can be driven directly from the main discharge controller of the spark generation system by applying electrical pulses directly to the motor windings using extension conductors. In other embodiments, the controller 1104 is a second and / or independent controller with separate regulation functions. For example, the controller 1104 can be mounted in a housing and can receive analog or digital signals (e.g., electrical, optical, and / or the like) from the primary controller of the spark generation system.

[0084] The electro-hydraulic shockwave generator disclosed herein produces an acoustic wavefront with improved acoustic wavefront uniformity. According to one embodiment, this improved acoustic wavefront uniformity is achieved through the use of an electro-hydraulic generator that uses a freeform acoustic reflector and a single servo motor electrode modulation system. As a result, the electro-hydraulic device disclosed herein provides a safer and more comfortable acoustic wave therapy when used to treat a patient.

[0085] The above specification and examples provide an explanation of the structure and use of the exemplary embodiments. Although certain embodiments have been described above with some specificity or with reference to one or more individual embodiments, those skilled in the art may make numerous modifications to the disclosed embodiments without departing from the scope of the present invention. Thus, the various illustrative embodiments of the device are not intended to be limited to the specific forms disclosed. Rather, they include all modifications and alternatives that fall within the scope of the claims, and embodiments other than those shown may include some or all of the features of the depicted embodiments. For example, components may be combined into a unitary structure. Furthermore, where appropriate, any aspect of the examples described above may be combined with any aspect of the other examples described to form further examples having the same or different properties and addressing the same or different problems. Similarly, it should be understood that the benefits and advantages described above may relate to one embodiment or to several embodiments.

[0086] The claims are not intended to, and should not be construed to, include means-plus or step-plus-function limitations, unless such limitations are expressly recited in a given claim using the phrase "means for" or "step for," respectively. [ka]

Claims

1. 1. A device for generating therapeutic acoustic waves, comprising: a housing defining a chamber and a shockwave outlet, the chamber configured to receive a liquid; a plurality of electrodes disposed within the chamber and configured to define a spark gap; a freeform acoustic reflector disposed within the chamber; and a single servo motor mechanically coupled to the plurality of electrodes; Equipped with Each of the spark gaps has a spark gap size and a spark gap position; the single servo motor is configured to adjust each electrode of the plurality of electrodes to maintain a constant spark gap size and spark gap position; The plurality of electrodes includes a first electrode and a second electrode, The apparatus, wherein the second electrode is configured to be modulated at a different rate than the first electrode.

2. The apparatus of claim 1 , wherein the freeform acoustic reflector is integral with the housing.

3. the plurality of electrodes are configured to generate a spark in the spark gap; when the chamber is filled with liquid and the electrodes generate the sparks, a plurality of acoustic waves are reflected from the freeform acoustic reflector out of the enclosure along wave paths; the freeform acoustic reflector is configured to reflect the plurality of acoustic waves such that the plurality of acoustic waves has a uniform unfocused pressure density at a target area; The apparatus of claim 1 , wherein the target area is an area along the wave path spaced from the housing by a first depth.

4. 4. The apparatus of claim 3, wherein the freeform acoustic reflector is configured to reflect the plurality of acoustic waves such that the plurality of acoustic waves has an average peak pressure variation at the target area of ​​less than 10%.

5. 4. The apparatus of claim 3, wherein the freeform acoustic reflector is configured to reflect the plurality of acoustic waves such that the plurality of acoustic waves has an average peak pressure variation at the target area of ​​less than 5%.

6. The apparatus of claim 3 , wherein the first depth is less than 10 mm.

7. the apparatus is configured to generate a plurality of acoustic waves along a wave path such that the plurality of acoustic waves has a first average peak pressure at a first depth and a second average peak pressure at a second depth further from the housing than the first depth; The apparatus of claim 1 , wherein the second average peak pressure is less than 50% of the first average peak pressure.

8. The apparatus of claim 7 , wherein the second depth is less than or equal to 700% of the first depth.

9. The apparatus of claim 7 , wherein the plurality of acoustic waves have an average peak pressure variation at the first depth of less than 10%.

10. The apparatus of claim 7 , wherein the first depth is less than 5 mm.

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