Rapid pulse electrohydraulic (EH) shockwave generator apparatus with improved electrode lifetime

Abstract

To provide a device for generating a therapeutic shock wave or a shock wave (a shock wave with therapeutic use).SOLUTION: A device, a capacitor array, and a method for generating a therapeutic compressed acoustic wave (e.g., a shock wave) are provided. In at least some of the devices and methods, a plurality of electrodes 306 may be disposed in a chamber 312 defined by a housing and configured to be filled with liquid, and a plurality of capacitors 310 may be electrically connected to the electrode and supported by the housing (e.g., physically coupled thereto). A voltage pulse may be applied to the plurality of electrodes and be simultaneously applied to the capacitors. The plurality of capacitors may be configured to discharge to a plurality of electrodes upon reaching a threshold charge.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] (Citation of Related Applications) This application claims the benefit of U.S. Provisional Application No. 62 / 365,099, filed Jul. 21, 2016, the contents of which are incorporated herein by reference.

[0002] (Field of the Invention) The present invention generally relates to the therapeutic use of shock waves or shockwaves. More specifically, but not limited to, the present invention relates to an apparatus for generating therapeutic shock waves or shockwaves (shock waves with therapeutic use), the apparatus having an improved electrode life.

Background Art

[0003] Acoustic shock waves have been used for certain treatments over the years. “Shock wave” or “shockwave” is generally used to refer to an acoustic phenomenon that produces a sudden and intense change in pressure (e.g., resulting from an explosion or lightning strike). These intense pressure changes can travel through elastic media such as air, water, human soft tissue, etc., and / or can generate strong energy waves that can induce an inelastic response in such elastic media. Methods for generating shock waves for therapeutic use include (1) electrohydraulic or spark gap (EH), (2) electromagnetic or EMSE, and (3) piezoelectric. Each is based on its own unique physical principle.

[0004] (A. Devices and Systems for Shock Wave Generation) U.S. Patent Application No. 13 / 574,228 (national stage application of PCT / US2011 / 021692, published as WO2011 / 091020 (Patent Document 1)) by one of the inventors of the present invention discloses a device for generating shock waves at a high pulse repetition rate using a transducer. The device includes an acoustic wave generator configured to emit acoustic waves having at least one frequency from 1 MHz to 1,000 MHz, a shock wave housing coupled to the acoustic wave generator, and a shock wave medium disposed within the shock wave housing. The device is configured such that when the acoustic wave generator emits acoustic waves, at least a portion of the acoustic waves will travel through the shock wave medium and form a shock wave. The device can be operated to form a shock wave configured to rupture one or more cells of a patient in particles within the patient, and the shock wave can be directed at the patient's cells such that the shock wave ruptures one or more of the cells in the particles. This acoustic transducer device can generate high-power shock waves at a high frequency or pulse repetition rate.

[0005] In addition, U.S. Patent Application No. 13 / 798712 by the inventors also discloses an apparatus and method for the electrohydraulic generation of shock waves at a rate of 10 Hz to 5 MHz, comprising a housing defining a chamber and a shock wave outlet, a liquid disposed within the chamber, a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps (e.g., within a spark head or module), and a pulse generation system configured to apply voltage pulses to the electrodes at a rate of 10 Hz to 5 MHz.

[0006] Other systems for generating shock waves can include an electrohydraulic (EH) wave generator. The EH system can generally deliver a similar level of energy as other methods, but is configured to deliver that energy over a wider area and thus deliver a greater amount of shock wave energy to the target tissue over a shorter period of time. The EH system generally incorporates electrodes (i.e., spark plugs) to initiate the shock wave. In the EH system, when electricity is applied to electrodes immersed in treated water contained within an enclosure, a high-energy shock wave is generated. When a charge is emitted, a small amount of water vaporizes at the tip of the electrode, and the rapid, almost instantaneous expansion of the vaporized water generates a shock wave that propagates outward through the liquid water. In some embodiments, the water is contained within an ellipsoidal enclosure. In these embodiments, the shock wave can bounce off the side of the ellipsoidal enclosure and converge at a focus that coincides with the location of the area to be treated.

[0007] For example, U.S. Patent No. 7,189,209 (the '209 patent) (Patent Document 2) describes a method for treating pathological conditions associated with bone and musculoskeletal environments as well as soft tissues by applying acoustic shock waves. The '209 patent states that the shock waves induce local trauma and cell apoptosis, including microdamage, therein, and induce osteogenic responses such as cell mobilization, and promote the formation of molecular bone, cartilage, tendon, fascia, and soft tissue morphogens and growth factors, and induce angiogenesis. The '209 patent claims several specific implementations of the method. For example, the '209 patent claims a method for treating diabetic foot ulcers or pressure ulcers in a human patient, which includes localizing the site or suspected site of the diabetic foot ulcer or pressure ulcer, generating acoustic shock waves, focusing the acoustic shock waves throughout the localized site, and applying more than 500 to about 2,500 acoustic shock waves per treatment to the localized site so as to induce an increase in microdamage and angiogenesis, thereby inducing or accelerating healing. The '209 patent discloses a frequency range of about 0.5 Hz to 4 Hz and the application of about 300 to 2,500 or about 500 to 8,000 acoustic shock waves per treatment site, which can result in a treatment duration for each treatment site and / or a "total time per treatment" for all sites that are unduly large. For example, the '209 patent discloses a total time per treatment ranging from 20 minutes to 3 hours for different examples.

[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 involves subjecting the bone to substantially 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 generate dynamic, repetitive loading to the bone, increasing average bone density and thereby strengthening the bone against fracture. As explained in the '572 patent, "the unfocused shock waves are preferably applied at a distance of, for example, 10 cm. 2 ~150cm 2 The shock waves are applied over a relatively large surface of the bone to be treated, so as to cover an area of ​​​​100 mm. The intensity of the shock waves can 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 for 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 shock waves to provide a therapeutic effect on tissue. The '293 Application discloses devices, systems, and methods for the generation of therapeutic acoustic shock waves to at least partially detach deposits from vascular structures. The '293 Application discloses a device that is capable of delivering shock waves up to 1 cm 2 It has been described that shock waves can be generated using from about 100 to about 5,000 pulses per treatment site (per length of vascular unit being treated) at a pulse repetition rate of from about 50 to about 500 pulses per minute (i.e., 0.83 Hz to 8.33 Hz).

[0010] (B.Shock wave speed) Prior art documents have shown that higher pulse repetition rates, which use an EH system to provide shock waves, can lead to tissue damage. For example, in one study (Delius, Jordan, & others, 1988)[2], the effect of shock waves on normal canine kidneys was examined in a group of dogs whose kidneys were exposed to 3,000 shock waves. The groups differed only in the shock wave delivery rates, which were 100 Hz and 1 Hz, respectively. Autopsies were performed 24 - 30 hours later. Macroscopically and histologically, significantly more bleeding occurred in the renal parenchyma when shock waves were delivered at a rate of 100 Hz (compared to 1 Hz). The results showed that kidney damage depends on the shock wave delivery rate.

[0011] In another study (Madbouly & others, 2005)[7], slow shock wave lithotripsy (SWL) rate was associated with a significantly higher success rate with a smaller number of total shock waves compared to rapid shock wave lithotripsy rate. In this paper, the authors discussed to what extent human experiments also showed a decrease in the incidence of SWL-induced kidney injury or a need for anesthesia when slower test SWL rates were used.

[0012] In yet another study (Gillitzer & others, 2009)[5], reducing the delivery rate of shock waves to 60 - 30 per minute was shown to also provide a dramatic protective effect on the integrity of actual blood vessels in a porcine model. These findings support a potential strategy of reduced pulse repetition rate frequencies to improve the safety and efficacy of extracorporeal shock wave lithotripsy.

[0013] Soft tissue can transition from elastic to viscous behavior with respect to a pulse repetition rate (PR) of 1 Hz to 10 Hz. As a result, potential damage to tissue from shock waves at a PR of 1 Hz to 10 Hz is not predictable when typical lithotripsy output levels are used. Perhaps as a result, the prior art teaches slower PRs and a large total time per treatment (TTPT). For example, currently known EH shock wave systems generally deliver a PR below 10 Hz and require a large total time per treatment (TTPT) (e.g., a TTPT period of minutes or even hours even for a single treatment site). As can be typical, when the treatment requires repositioning of the device at multiple treatment sites, the TTPT increases and can potentially be impractical for many patients and treatment needs.

[0014] Long treatment times may be acceptable for extracorporeal shock wave lithotripsy, but the use of shock waves to provide a non-lithotripsy treatment effect on tissue in a medical setting is not optimal if not impractical. For example, the cost of treatment often increases with the time required to perform the treatment (e.g., due to the cost of labor, equipment, and other resources allocated to the performance of the treatment). Further, in addition to cost, at some point, the duration of providing the treatment to a patient becomes intolerable for the patient receiving the treatment and the medical staff providing the treatment.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Means for Solving the Problems

[0016] This disclosure includes embodiments of an apparatus and method for the electrohydraulic generation of rapid acoustic pulses having an improved electrode life. In certain embodiments, this improved electrode life is achieved by utilizing a two-stage pulse discharge approach for shock wave generation. According to these embodiments, in a first stage, a pulse generation system simultaneously applies voltage pulses to a plurality of electrodes within an electrode chamber, to a plurality of capacitors positioned adjacent to the electrodes, and configures the plurality of capacitors to be charged such that a portion of the liquid contained therein is vaporized to provide a conductive path between the electrodes. In a second stage, the plurality of charged capacitors discharge to the electrodes, generating a short inter-electrode arc through the established conductive path between the electrodes, resulting in an acoustic shock wave. The short inter-electrode arc minimizes electrode erosion, leading to an improved electrode life.

[0017] The improved life of the electrodes is the result of a rapid discharge of capacitors positioned adjacent to the electrodes within the chamber. The pulse generation system simultaneously applies voltage pulses to a plurality of electrodes within an electrode chamber, to a plurality of capacitors positioned adjacent to the electrodes, and configures the plurality of capacitors to be charged such that a portion of the liquid contained therein is vaporized to provide a conductive path between the electrodes. In one embodiment, the plurality of capacitors comprises at least ten planar capacitors in parallel, each capacitor having a capacitance of 100 nanofarads or less. In one embodiment, the plurality of planar capacitors are installed on a plurality of stacked circuit boards adjacent to the electrodes, and the plurality of planar capacitors are installed on opposite sides of each stackable circuit board in a low inductance pattern. Installing these capacitors adjacent to the electrodes allows the arc to discharge completely and rapidly. When the capacitors are discharged, the inter-electrode arc terminates, which minimizes electrode erosion.

[0018] Some embodiments of the present device (e.g., for generating therapeutic shock waves) include a housing defining a chamber and a shock wave outlet, a liquid disposed within the chamber, a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps, a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes, and a pulse generation system configured to be coupled to the plurality of electrodes such that (i) the housing is movable relative to the pulse generation system and (ii) the pulse generation system is in electrical communication with the plurality of electrodes and the plurality of capacitors. The pulse generation system is configured to simultaneously apply a voltage pulse to the plurality of electrodes (e.g., to vaporize a portion of the liquid, initiate ionization, and provide at least one electrically conductive path between the plurality of electrodes) and to the plurality of capacitors (to charge the plurality of capacitors). The plurality of capacitors are configured to discharge to the plurality of electrodes upon reaching a threshold charge, generating one or more arcs along one or more electrically conductive paths between the electrodes, vaporizing a further portion of the liquid, and generating one or more acoustic shock waves.

[0019] In some embodiments of the present device, the pulse generation system is configured to provide an electrically conductive path between the electrodes by applying a voltage to charge the plurality of capacitors during a period in which the pulse generation system applies a voltage to the plurality of electrodes.

[0020] Some embodiments of the present device (e.g., for generating therapeutic shock waves) include a housing that defines a chamber and a shock wave outlet, the chamber being configured to be filled with a liquid, a housing, a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps, and a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes, and a pulse generation system configured to be coupled to the plurality of electrodes such that (i) the housing is movable relative to the pulse generation system and (ii) the pulse generation system is in electrical communication with the plurality of electrodes and the plurality of capacitors, whereby the plurality of electrodes and the plurality of capacitors can simultaneously receive voltage pulses from the pulse generation system. The pulse generation system is configured to simultaneously apply a voltage pulse to the plurality of electrodes (e.g., to vaporize a portion of the liquid, initiate ionization, and provide at least one electrically conductive path between the plurality of electrodes) and to the plurality of capacitors to charge the plurality of capacitors. The plurality of capacitors are configured to discharge to the plurality of electrodes when a threshold charge is reached, generating one or more arcs along one or more electrically conductive paths between the electrodes, vaporizing a further portion of the liquid, and generating one or more acoustic shock waves.

[0021] Some embodiments of the present device (e.g., for generating therapeutic shock waves) include a housing that defines a chamber and a shock wave outlet, the chamber being configured to be filled with a liquid, a housing, a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps, and a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes. The plurality of electrodes are configured to be coupled to a pulse generation system such that (i) the housing is movable relative to the pulse generation system and (ii) the pulse generation system is in electrical communication with the plurality of electrodes and the plurality of capacitors, whereby the plurality of electrodes and the plurality of capacitors can simultaneously receive voltage pulses from the pulse generation system. The plurality of capacitors are configured to discharge to the plurality of electrodes when a threshold charge is reached.

[0022] In some embodiments of the present device, each of the plurality of capacitors is planar. In some embodiments, the plurality of capacitors are arranged in a circuit having an overall inductance of 2 nH to 200 nH. In some embodiments, the plurality of capacitors comprises 2 to 20 sets of capacitors, and the capacitors of each set are connected in parallel. In some embodiments, each set of capacitors comprises fewer than 50 capacitors. In some embodiments, each set of capacitors comprises 10 or more capacitors in series.

[0023] In some embodiments of the present device, each capacitor has a capacitance of 100 nanofarads or less.

[0024] In some embodiments of the present device, a plurality of capacitors are coupled to a plurality of stackable circuit boards. In some embodiments, the plurality of capacitors are arranged in a plurality of circular patterns. In some embodiments, the plurality of stackable circuit boards include a first stackable circuit board and a second stackable circuit board coupled to the first stackable circuit board. In some embodiments, a first portion of the plurality of capacitors is coupled to the first stackable circuit board, and a second portion of the plurality of capacitors is coupled to the second stackable circuit board. In some embodiments, a first portion of the plurality of capacitors is disposed on a first side of the first stackable circuit board, and a second portion of the plurality of capacitors is disposed on a second side of the second stackable circuit board, and the second side of the second circuit board faces the first side of the first stackable circuit board. In some embodiments, the first stackable circuit board and the second stackable circuit board are circular. In some embodiments, a first portion of the plurality of capacitors is coupled to the first stackable circuit board, and a second portion of the plurality of capacitors is coupled to the second stackable circuit board. In some embodiments, a first portion of the plurality of capacitors is coupled to the first stackable circuit board in a circular pattern, and a second portion of the plurality of capacitors is coupled to the second stackable circuit board in a circular pattern. In some embodiments, each set of capacitors includes 10 or more capacitors in series. In some embodiments, the first stackable circuit board further includes an outer edge and a center, the second stackable circuit board further includes an outer edge and a center, a first portion of the plurality of capacitors is configured to allow current to flow from the outer edge of the first stackable circuit board towards the center of the first stackable circuit board, and a second portion of the plurality of capacitors is configured to allow current to flow from the outer edge of the second stackable circuit board towards the center of the second stackable circuit board. In some embodiments, the first stackable circuit board is electrically coupled to the second stackable circuit board by connectors disposed along the outer edge of the stackable circuit board. In some embodiments, each of the plurality of stackable circuit boards has a thickness of 0.02 inches to 0.2 inches.

[0025] In some embodiments of the present device, the plurality of capacitors each have a length of 2 mm to 4 mm and a width of 1 mm to 3 mm.

[0026] In some embodiments of the present device, the plurality of capacitors comprise at least 100 capacitors.

[0027] Some embodiments of the present capacitor array device (for example, for use in generating therapeutic shock waves) comprise one or more circuit boards and a plurality of capacitors coupled to the one or more circuit boards, wherein a first portion of the capacitors is arranged in a first pattern defined by a plurality of capacitor sets, a second portion of the plurality of capacitors is arranged in a second pattern defined by a plurality of capacitor sets, each capacitor set comprises two or more of the capacitors connected in series, the capacitor sets defining the first pattern are connected in parallel, the capacitor sets defining the second pattern are connected in parallel, and the one or more circuit boards are configured such that electrodes are in electrical communication with the capacitors and are coupled to the electrodes so as to be fixed in at least two degrees of freedom with respect to the one or more circuit boards.

[0028] In some embodiments of the present capacitor array device, the plurality of capacitors are planar. In some embodiments, the plurality of capacitors are arranged in a circuit having an overall inductance of 2 nH to 200 nH. In some embodiments, the plurality of capacitors comprise 2 to 20 sets of capacitors, and the capacitors of each set are connected in parallel. In some embodiments, each set of capacitors comprises fewer than 50 capacitors.

[0029] In some embodiments of the present capacitor array device, each set of capacitors comprises 10 or more capacitors in series.

[0030] In some embodiments of this capacitor array device, each capacitor has a capacitance of 100 nanofarads or less.

[0031] In some embodiments of this capacitor array device, one or more circuit boards comprise a plurality of stackable circuit boards. In some embodiments, the first and second patterns are circular. In some embodiments, the plurality of stackable circuit boards comprise a first stackable circuit board and a second stackable circuit board coupled to the first stackable circuit board. In some embodiments, a first portion of the capacitors is coupled to the first stackable circuit board and a second portion of the capacitors is coupled to the second stackable circuit board. In some embodiments, a first portion of the capacitors is disposed on a first side of the first stackable circuit board, and a second portion of the plurality of capacitors is disposed on a second side of the second stackable circuit board, and the second side of the second circuit board faces the first side of the first stackable circuit board. In some embodiments of this capacitor array device, a first portion of the plurality of capacitors is coupled to the first stackable circuit board in a circular pattern, and a second portion of the plurality of capacitors is coupled to the second stackable circuit board in a circular pattern. In some embodiments, each set of capacitors further comprises 10 or more capacitors connected in parallel. In some embodiments, the first stackable circuit board further comprises an outer edge and a center, the second stackable circuit board further comprises an outer edge and a center, and a first portion of the plurality of capacitors is configured to allow current to flow from the outer edge of the first stackable circuit board towards the center of the first stackable circuit board, and a second portion of the plurality of capacitors is configured to allow current to flow from the outer edge of the second stackable circuit board towards the center of the second stackable circuit board. In some embodiments, the first stackable circuit board is electrically coupled to the second stackable circuit board by a connector disposed along the outer edge of the stackable circuit board. In some embodiments, the plurality of stackable circuit boards each have a thickness of 0.02 inches to 0.2 inches.

[0032] In some embodiments of the present capacitor array device, the plurality of capacitors each have a length of 2 mm to 4 mm and a width of 1 mm to 3 mm.

[0033] In some embodiments of the present capacitor array device, the plurality of capacitors comprise at least 100 capacitors.

[0034] (For example, using a device for generating therapeutic shock waves to generate compressive acoustic waves) Some embodiments of the present method include applying a voltage pulse to a plurality of electrodes within a chamber defined by a housing and filled with a liquid such that a portion of the liquid vaporizes and begins to ionize, providing a conductive path between the electrodes; applying a voltage to a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes to charge the plurality of capacitors; discharging the plurality of capacitors to the electrodes when the plurality of capacitors reach a threshold charge to generate an arc between the electrodes along the established conductive path between the electrodes, thereby generating at least one acoustic shock wave. In some embodiments, the voltage pulse applied to the plurality of electrodes is from 500 V to 10,000 volts (V). In some embodiments, the voltage pulse applied to the plurality of capacitors is from 500 V to 10,000 V.

[0035] Although not necessarily direct and not necessarily mechanical, the term "coupled" is defined as connected, and the two items being "coupled" can be integral with each other. The terms "a" and "an" are defined as one or more unless the present disclosure explicitly requires otherwise. The term "substantially" is defined as mostly, but not necessarily the whole of what is specified (and includes what is specified, e.g., substantially 90 degrees includes 90 degrees, and substantially parallel includes parallel), as understood by one of ordinary skill in the art. In any of the disclosed embodiments, the terms "substantially", "approximately", and "about" may be substituted with "[a percentage]" "within" of what is specified, where the percentage includes 0.1, 1, 5, and 10 percent. In the disclosed embodiments, the term "adjacent" is generally defined as being located within the same individual chamber, housing, or module.

[0036] 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 non-limiting conjunctive verbs. As a result, a system or apparatus that "comprises", "has", "includes", or "contains" one or more elements possesses 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 possesses those one or more steps, but is not limited to possessing only those one or more steps.

[0037] Furthermore, a structure (e.g., a component of an apparatus) configured in a certain way is at least configured in that way, but it can also be configured in other ways than those specifically described.

[0038] Any embodiment of any of the systems, apparatuses, and methods described herein may not consist of, include, contain, or have any of the steps, elements, and / or features described, but may consist essentially of or consist of them. Thus, in any of the claims, the terms "consisting of" or "consisting essentially of" may be replaced with any of the non-limiting conjunctive verbs listed above to change the scope of a given claim, as would otherwise be done with non-limiting conjunctive verbs.

[0039] The embodiments described above and related details are presented below. The present invention provides, for example, the following. (Item 1) A capacitor array device for use in generating therapeutic shock waves, the device comprising: One or more circuit boards, each of the one or more circuit boards having a first side and a second side; A plurality of capacitors coupled to the one or more circuit boards; And comprising: A first portion of the capacitors is arranged in a first pattern defined by a first plurality of capacitor sets, a second portion of the plurality of capacitors is arranged in a second pattern defined by a second plurality of capacitor sets, and each capacitor set of the first plurality of capacitor sets and the second plurality of capacitor sets comprises two or more of the capacitors connected in series; The first plurality of capacitor sets defining the first pattern are connected in parallel, and the second plurality of capacitor sets defining the second pattern are connected in parallel; The one or more circuit boards are configured to be coupled to the electrodes such that the electrodes are in electrical communication with the capacitor and are fixed to the one or more circuit boards in at least two degrees of freedom, the device. (Item 2) At least one of the one or more circuit boards is disposed between one of the capacitor sets of the first portion of the capacitors and one of the capacitor sets of the second portion of the capacitors, the device according to item 1. (Item 3) The one or more circuit boards comprise a plurality of stackable circuit boards, the device according to item 1. (Item 4) The plurality of stackable circuit boards comprise a first stackable circuit board and a second stackable circuit board coupled to the first stackable circuit board, the device according to item 3. (Item 5) The first portion of the capacitors is coupled to the first stackable circuit board, and the second portion of the capacitors is coupled to the second stackable circuit board, the device according to item 4. (Item 6) The first portion of the capacitors is disposed on the first side of the first stackable circuit board, and the second portion of the plurality of capacitors is disposed on the second side of the first stackable circuit board, and the second side of the first stackable circuit board faces the first side of the first stackable circuit board, the device according to item 4. (Item 7) The first portion of the plurality of capacitors is coupled to the first stackable circuit board in a circular pattern shape such that the first portion of the plurality of capacitors extends radially away from the center of the first stackable circuit board, the device according to item 5. (Item 8) The second portion of the plurality of capacitors is coupled to the second stackable circuit board in a circular pattern shape such that the second portion of the plurality of capacitors extends radially so that the second portion of the plurality of capacitors is away from the center of the second stackable circuit board. The apparatus according to item 7. (Item 9) The first stackable circuit board further includes an outer edge, the second stackable circuit board further includes an outer edge, the first portion of the plurality of capacitors is configured to allow current to flow from the outer edge of the first stackable circuit board towards the center of the first stackable circuit board, and the second portion of the plurality of capacitors is configured to allow current to flow from the outer edge of the second stackable circuit board towards the center of the second stackable circuit board. The apparatus according to item 8. (Item 10) The first stackable circuit board is electrically coupled to the second stackable circuit board by a connector disposed along the outer edge of the stackable circuit board. The apparatus according to item 9. (Item 11) The electrode is fixed to the one or more circuit boards in at least two degrees of freedom. The apparatus according to item 1. (Item 12) The plurality of capacitors are planar. The apparatus according to item 1. (Item 13) The plurality of capacitors are arranged in a circuit having an overall inductance of 2 nH to 200 nH. The apparatus according to item 1. (Item 14) The plurality of capacitors include 2 to 20 sets of capacitors, and the capacitors of the set are connected in parallel. The apparatus according to item 1. (Item 15) The first set of the plurality of capacitors is coupled to the first stackable circuit board in a circular pattern shape such that the first set of the plurality of capacitors extends radially so that the first set of the plurality of capacitors is away from the center of the first stackable circuit board. The second set of the plurality of capacitors is coupled to the second stackable circuit board in a circular pattern shape such that the second set of the plurality of capacitors extends radially so that the second set of the plurality of capacitors is away from the center of the second stackable circuit board, the apparatus according to item 14. (Item 16) Each set of the plurality of capacitors further comprises 10 or more capacitors connected in parallel, the apparatus according to item 15.

Brief Description of the Drawings

[0040] The following drawings are illustrated by way of example, not limitation. For simplicity and clarity, not all features of a given structure are always labeled in all the figures in which that structure appears. The same reference numerals do not necessarily denote the same structure. Rather, the same reference numerals may be used to denote similar features or features with similar functionality that may be different reference numerals. The figures are drawn to scale (unless otherwise noted), meaning that the sizes of the depicted elements are accurate relative to each other at least with respect to the embodiments depicted in the figures.

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[0057] Certain embodiments of the present system and apparatus are configured to generate high frequency shockwaves while having an improved electrode life. In some embodiments, the generated EH shockwaves can be used in medical and / or aesthetic treatment applications (e.g., when directed towards a patient's target tissue and / or when delivered). Examples of medical and / or aesthetic treatment applications in which the present system 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 by reference in its entirety).

[0058] In one embodiment, an apparatus for the electrohydraulic generation of shock waves comprises a housing that defines a chamber and a shock wave 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 of 10 Hz to 5 MHz. The rate of the voltage pulses can be rates of 25 Hz, 50 Hz, 75 Hz, 100 Hz, 150 Hz, 200 Hz, 250 Hz, 300 Hz, 400 Hz, 500 Hz, 600 Hz, 700 Hz, 800 Hz, 900 Hz, 1 KHz, 5 KHz, 10 KHz, 25 KHz, 50 KHz, 100 KHz, 200 KHz, 300 KHz, 400 KHz, 500 KHz, 600 KHz, 700 KHz, 800 KHz, 900 KHz, 1 MHz, 2 MHz, 3 MHz, and 4 MHz.

[0059] (A. Prior art system) Referring now to the drawings, FIG. 1 depicts a typical pulse discharge from a prior art electrohydraulic system, which generates a broad frequency spectrum of acoustic waves (typically in the range of 16 Hz to 30 MHz), which consists of a large compression pulse wave 100 followed by a small tension wave. The compression pulse wave 100 consists of two parts: a steep rising acoustic front 104 (also referred to as a shock wave front), and a subsequent long compression acoustic tail 106. The rapid acoustic front 104 occurs on a nanosecond time scale, while the long compression acoustic tail 106 occurs on a microsecond time scale.

[0060] Such prior art electrohydraulic systems generate a pulse discharge event between two electrodes, and the pulse discharge event occurs in four stages: (1) heating and initial vaporization of the physiological saline between the electrodes, (2) vapor ionization, (3) arc formation between the electrodes, and (4) a concentrated arc.

[0061] Figure 2A depicts stage 1 of a prior art pulsed discharge event, namely, electrode - to - electrode saline heating and initial vaporization. During this stage of the pulse, chamber 200 is filled with saline 202. Next, the pulse generation system directly applies a voltage to electrodes 204, 206, creating a conductive path 208 between the electrodes. Specifically, current 210 is conducted from one electrode 204 through a bulk volume of saline 202 to the other 206. This results in the heating of saline 202, which in turn causes the saline 202 to be heated and a portion of it to vaporize at the initial nucleation sites located on the surface tips of electrodes 204, 206. Since the conductivity of saline increases with temperature, during this stage, the electrode current rises as the temperature of the saline increases. During this stage, no electrode damage exists during saline heating and initial vaporization. The current is distributed approximately uniformly across the surface tips of electrodes 204, 206, the temperature of the saline is low (up to about 100 °C), while the overall impedance is high (about 50 Ω for 1% saline).

[0062] Figure 2B depicts stage 2 of a prior art pulsed discharge event: inter - electrode vapor ionization, which overlaps stage 1 as depicted in Figure 2A. During this stage of the pulse, current 210 is still mainly conducted from one electrode 204 through a bulk volume of saline 202 to the other 206. Saline 202 continues to vaporize and expand from the initial nucleation sites. When the saline 202 vaporizes and its density becomes low enough, the increased free path of electrons allows them to acquire sufficient energy for collision ionization, and a streaming plasma discharge 212 is formed. As in stage 1, negligible electrode damage occurs during this stage. Ion sputtering can cause electrode material removal through sputtering, but the rate is extremely low when compared to stages 3 and 4 of the pulsed discharge event. The overall impedance is high (about 50 Ω for 1% saline).

[0063] Figure 2C depicts stage 3 of a prior art pulsed discharge event: inter-electrode arc formation. During this stage of the pulse, multiple events occur almost simultaneously. Discharge through the saline vapor plasma layer results in the formation of cathode and anode spots on the surface of the electrodes. These microscopic concentrated jets of electrode material and electrons supply the conductive material necessary to form a complete arc 214. The jets originating from the cathode and anode spots begin to connect and transition to the concentrated arc of stage 4. The net current across electrodes 204, 206 begins to spike as the initial arc 214 causes rapid and complete saline vaporization and arc spread. The overall impedance begins to drop to approximately 50 Ω to 0.1 Ω.

[0064] Figure 2D depicts stage 4 of a prior art pulsed discharge event: concentrated inter-electrode arc. The concentrated arc mode 216 appears to be very bright, covering the anode and cathode and filling the electrode gap 218. Additional spots and cathode spots are present, and they continuously emit electrode material into the gap 218, which supplies the feed material for the low-impedance arc. The concentrated arc mode 216 generated by prior art pulse generation systems is characterized by severe erosion at the anode and cathode [1]. Due to the low overall impedance (approximately 0.1 Ω), the arc voltage is low and the current is high. Anode spots tend to be fewer and more concentrated, while cathode spots are more numerous and more dispersed, so anode erosion is typically more severe than cathode erosion [1].

[0065] Severe erosion of electrodes 204, 206 using prior art electrohydraulic systems limits the lifespan of the electrodes in those systems. Since many applications for electrohydraulic systems require that numerous or rapid pulses be effective, prior art approaches for generating these acoustic waves result in a reduction in the limited lifespan of electrodes 204, 206, which requires either frequent electrode replacement or the use of an expensive and complex electrode feeding system. Due to the limited electrode lifespan, these requirements limit the commercial utility of electrohydraulic systems.

[0066] (B. Improved Systems, Components, and Methods) Certain embodiments of the present apparatus and method are configured to electrohydraulically generate shock waves while providing improved electrode lifespan. Certain embodiments achieve improved electrode lifespan by utilizing a two-stage pulse discharge approach for shock wave generation. In some embodiments, in a first stage, the pulse generation system is configured to simultaneously perform the following: (1) apply a voltage pulse to a plurality of electrodes within an electrode chamber such that a portion of the liquid contained within the chamber is vaporized, providing a conductive path between the electrodes; (2) apply a voltage pulse to charge a plurality of capacitors positioned adjacent to the plurality of electrodes. In such embodiments, in a second stage, the charged plurality of capacitors discharge, generating a short inter-electrode arc through the established conductive path between the electrodes, resulting in an acoustic shock wave. The short inter-electrode arc can minimize electrode erosion, thereby leading to improved electrode lifespan.

[0067] In electrohydraulic shock wave generation, high capacitance may be required to obtain the required peak pulse current with the desired waveform at the electrodes. In some of these embodiments, large capacitors may be placed in proximity to the electrodes and may be able to provide the high voltage pulses necessary to generate short interelectrode arcs. However, the use of repeated high voltages and current phase discharges required to generate the pulsed shock wave can cause damage to the large capacitors, which in turn can lead to shock wave generator failure. Capacitor damage sustained in these prior art systems is theorized to be due to the piezoelectric effect of the capacitor plates, which leads to mechanical failure. This problem can limit the ability to produce a commercially viable rapid pulse shock wave generator with an acceptable electrode life length.

[0068] In some of these embodiments, a plurality of small capacitors in parallel arranged adjacent to the electrodes (e.g., within or on the handheld housing in which the electrodes are disposed) (e.g., in a low inductance pattern) can be used to generate short interelectrode arcs. In this embodiment, a plurality of small capacitors in parallel arranged in a low inductance pattern adjacent to the electrodes can provide the repeated rapid high voltage and current pulse discharges required to generate a rapid pulse shock wave without damage to the capacitors. The piezoelectric effect on the materials for each small capacitor is limited when used in a plurality of small capacitors in parallel to generate a rapid pulse shock wave. As a result, in such embodiments, catastrophic capacitor mechanical failure is avoided, thereby improving the commercial viability of the rapid pulse shock wave generator.

[0069] In some of these embodiments, a plurality of small capacitors in parallel may be installed in a plurality of stacked circuit boards so as to reduce the area required for the capacitors. Additionally, installing a plurality of small capacitors on both sides of each stackable circuit board results not only in a further reduction in the surface area required for the capacitors, but also in a reduction of the inductance caused by the use of the plurality of capacitors.

[0070] Figure 3 depicts a representative schematic of one embodiment of the disclosed electrohydraulic device. In the embodiment shown, a pulse generation system 300 is coupled to a head 302 by a cable 304. The head 302 includes a plurality of electrodes 306 configured to define one or more spark gaps 308 and a plurality of capacitors 310 (e.g., the electrodes and capacitors are supported by a housing). As described below, the capacitors may be configured, for example, in a low inductance pattern. In some such embodiments, the housing or body of the head 302 defines a housing in which a plurality of electrodes 306 are disposed (e.g., a portion of each electrode extends into the chamber), and the plurality of capacitors 310 are supported by the housing (and / or may be disposed within a chamber 312). The chamber 312 is configured to be filled with a liquid. In the embodiment shown, the pulse generation system 300 includes a high voltage power supply 314, a capacitor 316, a primary switch 318, a current probe 320, a resistor 322, an inductor 324, and a voltage probe 326. The high voltage power supply 314 may be configured to supply, for example, 3,000 volts (V). The pulse generation system 300 is configured to apply a voltage pulse to the plurality of electrodes 306 such that a portion of the liquid disposed within the chamber 312 is vaporized, providing a conductive path between the electrodes. The pulse generation system 300 is also configured to apply a voltage to the plurality of capacitors 310 within the chamber (e.g., simultaneously). When charged, the plurality of capacitors 310 can discharge within the established conductive path between the electrodes, generating a short inter-electrode discharge arc. This discharge arc then results in the formation of a shock wave.

[0071] In some embodiments, such as those shown in FIGS. 4A-4E, at least some of the plurality of capacitors 310 are coupled to the stackable circuit board 400 in a circular low-inductance pattern on both the upper side 408 and the bottom side 406 of the stackable circuit board 400. FIG. 4A depicts a bottom view of an embodiment of a stackable circuit board 400 having a plurality of capacitors 310 coupled to the bottom side 406 of the stackable circuit board 400. In the embodiment shown, the stackable circuit board 400 is circular and has an outer edge 402 and a central opening 404. Surrounding the central opening 404, the stackable circuit board 400 has a plurality of additional openings 410 and a plurality of pins 412. In this embodiment, fourteen (14) pins 412 are coupled to the stackable circuit board 400. Other embodiments may include five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, or more pins 412 surrounding the central opening 404. The pins 412 can be, for example, pogo pins or other connectors configured to establish at least a temporary electrical connection between a plurality of circuit boards. Additionally, in the embodiment shown, the stackable circuit board 400 has a plurality of inter-board connectors 414 that run around its outer edge 402. The connectors 414 can be arranged in a single row or in two rows as shown, and can facilitate electrically coupling the stackable circuit board 400 to additional circuit boards. The connectors 414 can be configured to operate, for example, over a temperature range of -55°C to 125°C.

[0072] In the embodiment shown, capacitor 310 is coupled to the stackable circuit board 400 in a low inductance pattern. As shown, the low inductance pattern of the capacitor comprises a plurality of sets of capacitors, and each set of capacitors may comprise a plurality of individual capacitors. In the low inductance pattern, the sets of capacitors are arranged such that each set is in parallel with each other set. According to one embodiment, as shown in FIGS. 4A - 4E, each set of capacitors is coupled to the stackable circuit board 400 such that one capacitor is coupled to the board 400 in the vicinity of the central opening 404 and a plurality of additional capacitors are coupled to the board 400 such that they are in electrical communication with each other and extend radially towards the outer edge 402 away from the central opening 404. This portion of the capacitors from the set is further configured to be in electrical communication with an additional portion of the capacitors placed on the opposite side of the board (or, as shown in FIGS. 6A - 6D, another board). This additional portion of the capacitors is similarly configured such that they extend in series from the edge of the board 402 towards the central opening 404. According to the embodiment being described, the overall configuration of the capacitors is such that a plurality of sets of capacitors, each with a portion of the plurality of capacitors as a whole, extend outwardly from the central opening 404 towards the central edge 402, proceed to the opposite side of the board (or another board), and then extend back from the edge of the board 402 towards the central opening 404. When capacitor 310 is configured in such a manner, it can cause current to flow from the outer edge 402 of the stackable circuit board 400 towards the central opening 404, or from the central opening 404 of the stackable circuit board 400 towards the outer edge 402. Such a configuration has been shown to result in a reduced inductance across the entire capacitor array. For example, in some such embodiments, one set of capacitors is configured to cause current to flow radially inwardly, and the other sets of capacitors are configured to cause current to flow radially outwardly, which during use either cancels out the inductance or results in a "counter - flow" of currents that tend to (e.g., through interfering with each other in a weakening manner).In some embodiments, a portion of the capacitors is coupled to each of a plurality of stackable circuit boards, which may include two, three, four, five, or more individual boards. A portion of the plurality of capacitors may be coupled to one or both sides of any of the stackable circuit boards. As shown, the stackable circuit board 400 may be circular in shape and may have a notch 416 that extends inwardly from the outer edge 402 toward the central opening.

[0073] In one embodiment, at least ten (10) planar capacitors in parallel, each having a capacitance of 100 nanofarads (nF) or less, can provide the repeated high voltage pulse discharges required to generate rapid pulsed shock waves without damage to the capacitors. In other embodiments, at least 15, 20, 25, 30, 35, 40, 45, or 50 planar capacitors can be used in parallel. Additionally, according to other embodiments, each capacitor can have a maximum capacitance of 95 nF, 90 nF, 85 nF, 80 nF, 75 nF, 70 nF, 65 nF, 60 nF, 55 nF, or 50 nF. In one embodiment, the capacitors each have a length of 2 mm to 4 mm and a width of 1 mm to 3 mm.

[0074] In embodiments where capacitors are arranged in a set of capacitors, the plurality of capacitors are arranged in sets of 2 to 30 capacitors, and the sets can be connected in parallel (e.g., the capacitors within each set are connected in series). Alternatively, the plurality of capacitors can comprise 2, 5, 10, or 15 sets of capacitors. In some embodiments, each set of capacitors comprises fewer than 50 capacitors, but alternatively, each set can comprise 5, 10, 15, 20, 25, 30, 35, 40, or 45 capacitors. In some embodiments, the plurality of capacitors comprises at least 100 capacitors. In some embodiments, the plurality of capacitors is arranged in a circuit having an overall inductance of 2 nH to 200 nH.

[0075] Figures 5A - 5E depict a perspective view, a cross - sectional view, a top view, and a side view of one embodiment of the present stackable circuit board assembly including a capacitor array for use in a shock wave pulse generating device. Figure 5A depicts a perspective view of one embodiment of the present stackable circuit board assembly, Figure 5B depicts another perspective view of the assembly, Figure 5C depicts a side cross - sectional view of the assembly, Figure 5D depicts a top view of the assembly, and Figure 5E depicts a side view of the assembly. As shown, in this assembly, the circuit board 400 is coupled to a second stackable circuit board 500 via a connector 414. Thus, the capacitor 310 of the circuit board 400 is electrically connected to the second stackable circuit board 500 via the connector (414). The circuit board 400 is further mechanically coupled to the circuit board 500 via a central hub assembly 502. According to this embodiment, the circuit board 500 provides a low - inductance return path from the central pin to the outermost row of the capacitors 310.

[0076] Figures 6A - 6D depict a perspective view, a cross - sectional view, and an exploded perspective view of another embodiment of the present capacitor array for use in a shock wave generating device and method for rapid treatment. Figure 6A depicts a perspective view of the capacitor array, Figure 6B depicts a second perspective view of the capacitor array, Figure 6C depicts a cross - sectional view of the capacitor array, and Figure 6D depicts an exploded view of the capacitor array. In this embodiment, a plurality of capacitors 310 are installed on a first stacked circuit board 400 and a second stacked circuit board 500 adjacent to a plurality of electrodes. A plurality of small capacitors 310 are installed on both sides of each stackable circuit board 400, 500 in a low - inductance pattern. Both of the circuit boards 400, 500 are electrically coupled to each other via an inter - board connector 414 and mechanically coupled to each other via a central mechanical assembly 502.

[0077] In the illustrated embodiment, installing a plurality of capacitors 310 in the vicinity of the electrodes enables the arc to be discharged completely and rapidly. When the capacitors 310 in the chamber head (as illustrated by the embodiment depicted in FIG. 3) are discharged, the inter-electrode arc terminates and electrode erosion is minimized.

[0078] In some embodiments, the improved lifespan of the electrodes is the result of the discharge of a plurality of capacitors 310 in the vicinity of the electrodes. Installing a plurality of capacitors 310 in the vicinity of the electrodes in a low-inductance pattern provides an overall low inductance for the capacitor / electrode configuration. As a result, the plurality of capacitors 310 in the chamber can be discharged completely and rapidly.

[0079] As shown, the central mechanical assembly 502 includes a contact ring 600, a ring adapter 602, a spacer 604, an exchange pin socket 606, a central pin 608, and a plurality of nuts 610. The ring adapter 602 may have a plurality of teeth 612 configured to be inserted into an opening in the second stackable circuit board 500, whereby the teeth 612 prevent the second stackable circuit board 500 from rotating independently of the ring adapter 602.

[0080] In the illustrated embodiment, the capacitors may be configured to flow current from the center of the second stackable circuit board 500, towards its outer edge, through the inter-board connector 414, to the outer edge of the first stackable circuit board 400, and from there to the center of the first stackable circuit board 400. Each stackable circuit board 400, 500 may have a thickness of 0.02 - 0.2 inches. Alternatively, the substrates 400, 500 may have a thickness of 0.03 - 0.125 inches or 0.04 - 0.1 inches.

[0081] Figures 7A - 7C depict cross - sectional and side views of one embodiment of the disclosed capacitor array coupled shock wave generation chamber. According to an embodiment as shown in Figure 7A, capacitor array 700 is coupled to a plurality of electrodes having a proximal electrode 702 and a distal electrode 704. In this embodiment, both the proximal electrode 702 and the distal electrode 704 are disposed within a chamber 706 configured to be filled with a liquid. In at least one embodiment, chamber 706 is configured to be filled with saline. In yet another embodiment, chamber 706 is filled with saline. Electrodes 702, 704 are configured to have a short gap therebetween that defines a discharge location 708. Capacitor array 700, together with the coupled electrodes 702, 704, and chamber 706, is configured to implement a two - stage discharge approach for shock wave generation. In the first stage, the pulse generation system is configured to simultaneously: (1) apply a voltage pulse to the plurality of electrodes 702, 704 within electrode chamber 706 such that a portion of the liquid contained within chamber 706 is vaporized and provides an inter - electrode conductive path within discharge location 708; (2) apply a voltage pulse to charge a plurality of capacitors positioned adjacent to the plurality of electrodes 702, 704 within capacitor array 700. According to this embodiment, in the second stage, the charged plurality of capacitors discharge, generating a short inter - electrode arc through the established inter - electrode conductive path within discharge location 708, resulting in an acoustic shock wave.

[0082] In some embodiments, using a two - stage pulsed discharge approach for generating shock waves results in a short inter - electrode arc time that minimizes electrode erosion and leads to improved electrode life. Electro - hydraulic systems that use a single - stage pulsed discharge approach (e.g., the pulse generation system directly applies a voltage pulse to the electrodes, continuously forms an inter - electrode conductive path, and then generates an inter - electrode arc) suffer from long discharge arc times and thus significant electrode erosion. This significant electrode erosion leads to electro - hydraulic shock wave devices with short electrode life, increasing the time and cost required for maintenance.

[0083] For example, FIGS. 8A and 8B depict photographs comparing electrodes used by prior art systems that are compared to the electrodes implementing the disclosed system. FIG. 8A depicts one embodiment of an electrode activated using a prior art pulsed power supply that uses a single-step approach. In contrast, FIG. 8B depicts an electrode activated using one embodiment of the two-step pulse generation system disclosed herein. As can be seen by comparing FIGS. 8A and 8B, the electrode activated using the prior art pulsed power supply (FIG. 8A) showed significant erosion after fewer than 100 pulses. The large indentations indicate substantial electrode melting due to the long and severe arc durations resulting from the single-step prior art system. In contrast to the electrodes implementing the prior art system, the electrode activated using the two-step pulse generation system (FIG. 8B) demonstrated only minimal erosion after 6,200 pulses. The electrodes implementing the two-step system had a 15-fold reduction in wear rate when compared to those implementing the prior art system. For example, at an equivalent pulse rate, the electrode depicted in FIG. 8A coupled to the prior art pulse generation system exhibited a wear rate of approximately 3,750 microinches per minute, while the electrode depicted in FIG. 8B coupled to one of the inventive two-step pulse generation approaches (including the pulse generation system and the housing supported capacitor array) exhibited a wear rate of only 250 microinches per minute.

[0084] In addition, according to one embodiment, the apparatus and method for electrohydraulic generation of shock waves using the two-stage approach disclosed herein generate "compressed" acoustic waves when compared to those waves generated by prior art systems. FIG. 9 depicts a graph illustrating the pressure over time of both the acoustic waves generated by a prior art system 900 and the acoustic waves generated by the proposed two-stage approach 902. As can be seen from FIG. 9, the acoustic waves generated by the two-stage approach have an acoustic front 904 that rises more rapidly than that of the prior art approach when compared to the prior art system. More importantly, the long acoustic tail 906 is significantly compressed as a result of the rapid capacitor discharge time into an already established conductive path between the electrodes. Finally, the two-stage approach injects more energy into the acoustic pulse and less total energy into the arc when compared to the prior art approach. The less total energy into the arc directly leads to improved electrode life.

[0085] Furthermore, the compressed acoustic waves depicted in FIG. 9 are less painful and cause less damage when applied to tissue. A typical pulsed discharge from a prior art electrohydraulic system typically generates an acoustic wave with a broad frequency spectrum in the range of 16 Hz to 30 MHz. The long compressed tail 906 of the acoustic wave consists of acoustic waves in the lower frequency spectrum. These low frequency components at typically used acoustic pressures are the main source of large cavitation bubbles. These large cavitation bubbles cause pain and tissue damage when generated within the tissue. Due to the short capacitor discharge and resulting rapid arc, the long compressed tail 906 of the acoustic wave is compressed. As a result, the large cavitation bubbles due to the long tail are minimized.

[0086] In one embodiment, the shock wave generation system and apparatus incorporate the probe depicted in FIGS. 10 - 12C. In this embodiment, the probe 1000 includes a housing 1002 that defines a chamber 1004 and a shock wave exit 1006, a liquid disposed within the chamber 1004, and a plurality of electrodes 306 disposed within the chamber and configured to define one or more spark gaps (e.g., within a spark head or module 1008), and is configured to be coupled to a pulse generation system (300) configured to apply voltage pulses to the electrodes at a rate of 10 Hz to 5 MHz.

[0087] In the illustrated embodiment, the spark head 1008 includes a sidewall or body 1010 and a plurality of electrodes 306 that define a spark gap. In this embodiment, the probe 1000 is configured to allow liquid to circulate through the chamber 1004 via liquid connectors or ports 1012 and 1014, and as shown, one of them is coupled to the spark head 1008 and the other of them is coupled to the housing 1002. In this embodiment, the housing 1002 is configured to receive the spark head 1008 such that the housing 1002 and the housing 1010 cooperate to define the chamber 1004 (e.g., include complementary parabolic surfaces such that the spark head 1008 and the housing 1002 cooperate to define the chamber). In this embodiment, the housing 1002 and the spark head 1008 include a channel 1016 (e.g., along the central longitudinal axis of the spark head 1008) that extends between the liquid connector 1012 and the chamber 1004 and is aligned with the spark gap between the electrodes 306 such that the circulating water will flow proximate to and / or through the spark gap. In the illustrated embodiment, the housing 1002 includes a channel 1018 that extends between the liquid connector 1014 and the chamber 1004. In this embodiment, the housing 1010 includes a groove 1020 configured to receive an elastic gasket or O-ring 1022 to seal the interface between the spark head 1008 and the housing 1002, and the housing 1002 includes a groove 1024 configured to receive an elastic gasket or O-ring 1026 to seal the interface between the housing 1002 and the cap member 1028 when the cap member 1028 is fixed to the housing 1002 by a ring 1030 and a restraint collar 1032.

[0088] In the illustrated embodiment, each of the electrodes 306 includes a flat bar portion 1034 and a vertical cylindrical portion 1036 that is in electrical communication with (e.g., integral with) the bar portion 1034 (e.g., comprises tungsten for durability), and the cylindrical portion 1036 can extend into the chamber 1004 through a corresponding opening 1038 in the spark head 1008 as shown. In some embodiments, a portion of the side surface of the cylindrical portion 1036 can be coated with an electrically insulating and / or elastic material (e.g., shrink wrap), for example, to seal the interface between the portion 1036 and the housing 1010. In this embodiment, the housing 1010 also includes a longitudinal groove 1038 that is configured to receive the bar portion 1034 of the electrode 306. In the illustrated embodiment, the housing 1002 includes a set screw 1040 that is positioned such that the spark head 1008 is aligned with the cylindrical portions 1036 of the electrodes 306 when the spark head 1008 is disposed within the housing 1000, so that the set screw 1040 can be tightened to push the cylindrical portion 1036 inward and adjust the spark gap between the cylindrical portions of the electrodes 306. In some embodiments, the spark head 1008 is permanently adhered to the housing 1002; however, in other embodiments, the spark head 1008 can be removable from the housing 1002, for example, to allow for replacement of the electrodes 306, individually or as part of a new or replacement spark head 1008.

[0089] The foregoing specification and examples provide an explanation of the structure and use of exemplary embodiments. Although certain embodiments have been described above to a certain degree of particularity, 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 invention. Accordingly, 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 within the scope of the claims, and embodiments other than those shown may include some or all of the features of the described embodiments. For example, components may be combined as an integral structure. Further, where appropriate, any aspect of any of the examples described may be combined with any aspect of any of the other examples described to form additional examples that are equivalent or have different properties and address the same or different problems. Similarly, the benefits and advantages described above may be associated with one embodiment or may be associated with several embodiments.

[0090] The claims are not intended to, and should not be construed to, include means-plus or step-plus-function limitations, such that such limitations are not expressly recited in a given claim using the phrase "means for" or "step for" respectively.

[0091] (References) The following references are specifically incorporated herein by reference to the extent that they provide exemplary procedure details or other details that supplement those described herein. [1]Raymond L. Boxman, Philip J. Martin, David Sanders (1995). Handbook of Vacuum Arc Science and Technology: Fundamentals and Applications, Park Ridge, NJ: Noyes Publications, pp. 316 - 319 [2]V.Ya.Ushakov, et al. (2007). Impulse Breakdown of Liquids, New York, NY: Springer [3]Schmitz C, et al. Treatment of chronic plantar fasciopathy with extracorporeal shock waves (review). Journal of Orthopaedic Surgery and Research 2013 8:31 [4]U.S. Patent No. 8,672,721, entitled "High power discharge fuel igniter" by L. Camilli [5]U.S. Patent No. 5,245,988, entitled "Preparing a circuit for the production of shock waves" by W. Einars, et al. [6]U.S. Patent No. 4,005,314, entitled "Short pulse generator" by M. Zinn [7]German Patent No. DE 3150430 CI, entitled "Circuit for generating an underwater discharge" by G. Heine, et al. [8]U.S. Patent No. 3,604,641, entitled "Apparatus for hydraulic crushing" by B.R. Donoghue, et al.

Claims

1. 1. An apparatus for generating therapeutic shock waves, the apparatus comprising: a housing defining a chamber and a shock wave outlet; a liquid disposed in the chamber; a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps; a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes; Pulse generating system and Equipped with the pulse-generating system is configured such that (i) the housing is movable relative to the pulse-generating system, and (ii) the pulse-generating system is coupled to the plurality of electrodes such that the pulse-generating system is in electrical communication with the plurality of electrodes and the plurality of capacitors; The pulse generating system comprises: applying a voltage pulse to the plurality of electrodes to begin to vaporize and ionize a portion of the liquid and provide at least one inter-electrode conductive path between the plurality of electrodes; applying a voltage pulse to the plurality of capacitors to charge the plurality of capacitors; and The apparatus is configured such that upon reaching a threshold charge, the plurality of capacitors discharge to the plurality of electrodes, generating one or more arcs along the one or more inter-electrode conductive paths, vaporizing a further portion of the liquid, and generating one or more acoustic shock waves.

2. 1. An apparatus for generating therapeutic shock waves, the apparatus comprising: a housing defining a chamber and a shockwave outlet, the chamber configured to be filled with a liquid; a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps; a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes; Pulse generating system and Equipped with the pulse-generating system is configured such that (i) the housing is movable relative to the pulse-generating system, and (ii) the pulse-generating system is coupled to the plurality of electrodes such that the pulse-generating system is in electrical communication with the plurality of electrodes and the plurality of capacitors; The pulse generating system comprises: applying a voltage pulse to the plurality of electrodes to begin to vaporize and ionize a portion of the liquid and provide at least one inter-electrode conductive path between the plurality of electrodes; applying a voltage pulse to the plurality of capacitors to charge the plurality of capacitors; and The apparatus is configured such that upon reaching a threshold charge, the plurality of capacitors discharge to the plurality of electrodes, generating one or more arcs along the one or more inter-electrode conductive paths, vaporizing a further portion of the liquid, and generating one or more acoustic shock waves.

3. 1. An apparatus for generating therapeutic shock waves, the apparatus comprising: a housing defining a chamber and a shockwave outlet, the chamber configured to be filled with a liquid; a plurality of electrodes disposed within the chamber and configured to define one or more spark gaps; a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes; Equipped with the plurality of electrodes are configured to be coupled to a pulse-generation system such that (i) the housing is movable relative to a pulse-generation system, and (ii) the pulse-generation system is in electrical communication with the plurality of electrodes and the plurality of capacitors, such that the plurality of electrodes and the plurality of capacitors can simultaneously receive voltage pulses from the pulse-generation system; The apparatus, wherein the plurality of capacitors are configured to discharge onto the plurality of electrodes upon reaching a threshold charge.

4. The apparatus of claim 1 , 2 or 3 , wherein each of the plurality of capacitors is planar.

5. 5. The apparatus of claim 4, wherein the plurality of capacitors are arranged in a circuit having an overall inductance between 2nH and 200nH.

6. 6. The apparatus of claim 5, wherein the plurality of capacitors comprises between 2 and 20 sets of capacitors, the sets of capacitors being connected in parallel.

7. 7. The apparatus of claim 6, wherein each set of capacitors comprises fewer than 50 capacitors.

8. 7. The apparatus of claim 6, wherein each set of capacitors comprises 10 or more capacitors in series.

9. 4. The apparatus of claim 1, 2 or 3, wherein each capacitor has a capacitance of 100 nanofarads or less.

10. The apparatus of claim 1 , 2 or 3 , wherein the plurality of capacitors are coupled to a plurality of stackable circuit boards.

11. The apparatus of claim 10 , wherein the plurality of capacitors are arranged in a plurality of circular patterns.

12. The apparatus of claim 10 , wherein the plurality of stackable circuit boards comprises a first stackable circuit board and a second stackable circuit board coupled to the first stackable circuit board.

13. 13. The apparatus of claim 12, wherein a first portion of the plurality of capacitors is coupled to the first stackable circuit board and a second portion of the plurality of capacitors is coupled to the second stackable circuit board.

14. 14. The apparatus of claim 13, wherein the first portion of the plurality of capacitors is disposed on a first side of the first stackable circuit board and the second portion of the plurality of capacitors is disposed on a second side of the second stackable circuit board, the second side of the second circuit board facing the first side of the first stackable circuit board.

15. The apparatus of claim 14 , wherein the first stackable circuit board and the second stackable circuit board are circular.

16. 16. The apparatus of claim 15, wherein the first portion of the plurality of capacitors is coupled to the first stackable circuit substrate and the second portion of the plurality of capacitors is coupled to the second stackable circuit substrate.

17. the first portion of the plurality of capacitors is coupled to the first stackable circuit board in a circular pattern; the second portion of the plurality of capacitors is coupled to the second stackable circuit substrate in a circular pattern.

17. The apparatus of claim 16.

18. 20. The apparatus of claim 17, wherein each set of capacitors comprises 10 or more capacitors in series.

19. 20. The apparatus of claim 17, wherein the first stackable circuit board further comprises an outer edge and a center, and the second stackable circuit board further comprises an outer edge and a center, and the first portion of the plurality of capacitors is configured to direct current to flow from an outer edge of the first stackable circuit board toward a center of the first stackable circuit board, and the second portion of the plurality of capacitors is configured to direct current to flow from an outer edge of the second stackable circuit board toward a center of the second stackable circuit board.

20. 20. The apparatus of claim 19, wherein the first stackable circuit board is electrically coupled to the second stackable circuit board by connectors disposed along an outer edge of the stackable circuit board.

21. The apparatus of claim 10, wherein the plurality of stackable circuit boards each have a thickness between 0.02 inches and 0.2 inches.

22. 3. The apparatus of claim 1, wherein the pulse-generating system is configured to provide an inter-electrode conductive path by applying a voltage to charge the plurality of capacitors during a period when the pulse-generating system applies a voltage to the plurality of electrodes.

23. 4. The apparatus of claim 1, 2 or 3, wherein the plurality of capacitors each have a length of between 2 mm and 4 mm and a width of between 1 mm and 3 mm.

24. 4. The apparatus of claim 1, 2, or 3, wherein the plurality of capacitors comprises at least 100 capacitors.

25. 1. A capacitor array apparatus for use in generating therapeutic shock waves, the apparatus comprising: one or more circuit boards; a plurality of capacitors coupled to the one or more circuit boards; Equipped with a first portion of the capacitors are arranged in a first pattern defined by a plurality of capacitor sets and a second portion of the plurality of capacitors are arranged in a second pattern defined by a plurality of capacitor sets, each capacitor set comprising two or more of the capacitors connected in series, the capacitor sets defining the first pattern being connected in parallel and the capacitor sets defining the second pattern being connected in parallel; the one or more circuit boards are configured to couple to the electrodes such that the electrodes are in electrical communication with the capacitor and are fixed in at least two degrees of freedom relative to the one or more circuit boards.

26. 26. The apparatus of claim 25, wherein the plurality of capacitors are planar.

27. 26. The apparatus of claim 25, wherein the plurality of capacitors are arranged in a circuit having an overall inductance between 2nH and 200nH.

28. 27. The apparatus of claim 26, wherein the plurality of capacitors comprises between 2 and 20 sets of capacitors, the sets of capacitors being connected in parallel.

29. 30. The apparatus of claim 28, wherein each set of capacitors comprises fewer than 50 capacitors.

30. 26. The apparatus of claim 25, wherein each set of capacitors comprises 10 or more capacitors in series.

31. 26. The apparatus of claim 25, wherein each capacitor has a capacitance of 100 nanofarads or less.

32. 26. The apparatus of claim 25, wherein the one or more circuit boards comprise a plurality of stackable circuit boards.

33. 33. The apparatus of claim 32, wherein the first and second patterns are circular.

34. 33. The apparatus of claim 32, wherein the plurality of stackable circuit boards comprises a first stackable circuit board and a second stackable circuit board coupled to the first stackable circuit board.

35. 35. The apparatus of claim 34, wherein the first portion of the capacitor is coupled to the first stackable circuit board and the second portion of the capacitor is coupled to the second stackable circuit board.

36. 36. The apparatus of claim 35, wherein the first portion of the capacitors is disposed on a first side of the first stackable circuit board and the second portion of the plurality of capacitors is disposed on a second side of the second stackable circuit board, the second side of the second circuit board facing the first side of the first stackable circuit board.

37. the first portion of the plurality of capacitors is coupled to the first stackable circuit board in a circular pattern; the second portion of the plurality of capacitors is coupled to the second stackable circuit substrate in a circular pattern.

36. The apparatus of claim 35.

38. 40. The apparatus of claim 37, wherein each set of capacitors further comprises 10 or more capacitors connected in parallel.

39. 38. The apparatus of claim 37, wherein the first stackable circuit board further comprises an outer edge and a center, and the second stackable circuit board further comprises an outer edge and a center, and the first portion of the plurality of capacitors is configured to direct current to flow from an outer edge of the first stackable circuit board toward a center of the first stackable circuit board, and the second portion of the plurality of capacitors is configured to direct current to flow from an outer edge of the second stackable circuit board toward a center of the second stackable circuit board.

40. 40. The apparatus of claim 39, wherein the first stackable circuit board is electrically coupled to the second stackable circuit board by connectors disposed along an outer edge of the stackable circuit board.

41. 33. The apparatus of claim 32, wherein the plurality of stackable circuit boards each have a thickness between 0.02 inches and 0.2 inches.

42. 26. The apparatus of claim 25, wherein the plurality of capacitors each have a length of between 2 mm and 4 mm and a width of between 1 mm and 3 mm.

43. 26. The apparatus of claim 25, wherein the plurality of capacitors comprises at least 100 capacitors.

44. 1. A method of generating compression acoustic waves using a device for generating therapeutic shock waves, the method comprising: applying a voltage pulse to a plurality of electrodes within a chamber defined by an enclosure and filled with the liquid such that a portion of the liquid begins to vaporize and ionize, providing an inter-electrode conductive path; applying a voltage to a plurality of capacitors supported by the housing and in electrical communication with the plurality of electrodes to charge the plurality of capacitors; discharging the plurality of capacitors to the electrodes when the plurality of capacitors reaches a threshold charge, creating an inter-electrode arc along the established inter-electrode conductive path, thereby creating at least one acoustic shock wave; A method comprising:

45. 45. The method of claim 44, wherein the voltage pulses applied to the plurality of electrodes are between 500V and 10,000V.

46. 45. The method of claim 44, wherein the voltage pulse applied to the plurality of capacitors is between 500V and 10,000V.

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