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    • 专利摘要:
    Controlled solid fragmentation system using vortex acoustic beams. The present invention refers to a system for the controlled fragmentation of solids using acoustic beams, comprising at least one unit (100) for generating acoustic beams; and a feedback and control unit (200) of said generation unit (100). Advantageously, the acoustic beams generated by the system are vortex acoustic beams; and the feedback and control unit (200) further comprises a feedback subsystem (12), configured to receive the information related to the fragmented solids and take advantage of it to adapt the operation of the acoustic beam generation unit (100). Since the generation of shear stresses is more efficient using vortex beams, the amplitudes of the ultrasonic field required to fragment the stones are much lower than in current extracorporeal shock wave lithotripsy techniques. Also, the system minimizes unwanted effects on the soft tissues surrounding the solid. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2811092A1
    申请号:ES202030757
    申请日:2020-07-20
    公开日:2021-03-10
    发明作者:Gonzalez Noé Jimenez；Femenia Francisco Camarena；Baviera José María Benlloch
    申请人:Consejo Superior de Investigaciones Cientificas CSIC；Universidad Politecnica de Valencia；
    IPC主号:
    专利说明:

    [0002] SOLIDS CONTROLLED FRAGMENTATION SYSTEM USING ACOUSTIC VORTEX BEAMS
    [0004] FIELD OF THE INVENTION
    [0006] The present invention is related to the technologies of interaction of ultrasonic acoustic beams with biological matter and tissues. More specifically, the invention relates to a vortex acoustic beam system for the fragmentation of hardened masses or calculi, in a minimally invasive manner. In this system, the vortex beams can be modulated in intensity, phase, repetition rate, topological load, etc., according to the size, location and composition of the mass to be destroyed, as well as the energy that said beam transfers to mass.
    [0008] BACKGROUND OF THE INVENTION
    [0010] Until the early 1980s of the 20th century, most kidney stones were treated with open surgery. Advances in minimally invasive ureterorenoscopy (URS) and percutaneous nephrostolithotomy (or nephrolithotomy) techniques (PCNL), along with the advent of non-invasive extracorporeal shock wave lithotripsy (ESWL) systems, has led to the abandonment of treatments surgical openings to remove kidney and / or gallstones, as disclosed for example in N. Bhojani and JE Lingeman, "Shockwave Lithotripsy-New Concepts and Optimizing Treatment Parameters", Urol. Clin. North Am., Vol. 40, no. 1 p. 59-66, 2013.
    [0012] The first ESWL treatment was performed in 1980 in Germany, using a Dornier "Human Model 1" (HM1) lithotripter (see C. Chaussyet al., "Extracorporeally Induced Destruction of Kidney Stones by Shock Waves", Lancet, vol. 316, no. 8207, pp. 1265-1268, 1980) The clinical use of the ESWL lithotripsy technique has rapidly become widespread for kidney stone fragmentation due to its effectiveness and reduced side effects.
    [0014] Unlike URS and PCNL, the goal of ESWL treatments is stone fragmentation, not stone extraction. This is achieved by subjecting the calculation to a series of high amplitude ultrasonic pulses. These pulses are mechanical waves that produce shear stresses within the stones and high internal stresses. After undergoing such mechanical stresses the stone fractures into smaller fragments that are expelled by the same organism naturally (see JJ Rassweiler et al., "Shock Wave Technology and Application: An Update", Eur. Uml., vol.
    [0015] 59, no. 5 p. 784-796, 2011).
    [0017] The acoustic energy of the ESWL is concentrated in a relatively small area, surrounding the focal point of the lithotriptory is the location of the kidney stone of interest. The focal zone can be small or large, and the amount of energy or maximum pressure applied to it can be manipulated. Typical targeting values for modern lithotripters are pressures between 50 and 150 MPa, delivered to a focal zone between 3 and 6 mm, as mentioned in the document C. Chaussy et al. previously referenced. However, high targeting does not ensure the effectiveness of the treatment. More focused lithotripters tend to have fewer shock waves that actually impact the stone, leaving a remnant of shock wave energy that is deposited directly into the kidney tissue (see RO Cleveland et al., "Effect of Stone Motion on in Vitro Comminution Efficiency of Storz Modulith SLX ”, J. Endourol., Vol. 18, no. 7, p.
    [0018] 629-633, 2004). Since the stone will have a better chance of staying within the focal zone during treatment if the zone is larger, there are devices that work with lower pressures and wider focal regions, for example 20 MPa on a 20 mm focus. Wide focal zone lithotripters produce smaller kidney lesions and are therefore more advantageous, as disclosed in the references (see AP Evan et al., “Independent assessment of a wide-focus, low-pressure electromagnetic lithotripter: absence of renal bioeffects in the pig ", BJU Int., vol. 101, no. 3, p. 382-388, 2008; JA McAteer et al.," Independent Evaluation of the Lithogold LG-380 Lithotripter: In Vitro Acoustic Characteristics and Assessment of Renal Injury in the Pig Model ”, J. Urol., vol. 181, no. 4, p. 665-666, 2009). Furthermore, the shear waves necessary to cause large internal stresses have been shown to increase when the focal width is greater than the diameter of the stone (see RO Cleveland and OA Sapozhnikov, "Modeling elastic wave propagation in kidney stones with application to shock wave lithotripsy ”, J. Acoust. Soc. Am., Vol. 118, no. 4, p. 2667-2676, 2005).
    [0020] Currently, all lithotripters require four common elements: a mechanism for generating high-intensity ultrasonic waves, a mechanism for targeting these waves, a means of coupling between the generation system and the patient's body, and a system for locating the ultrasonic waves. calculations for treatment planning and monitoring.
    [0021] Mainly, there are three types of technologies for the generation of ultrasonic waves: electrohydraulic, piezoelectric and electromagnetic systems.
    [0023] First, electrohydraulic generation systems produce shock waves by means of an electric arc located on a first focus, F1, of an ellipsoidal reflector. The device is positioned so that the stone is located on the second geometric focus of the ellipsoidal reflector, commonly called F2. Thus, the shock wave front propagates from the first focus, passing through a water bath that in turn serves as an acoustic coupling with the patient's body, to the second geometric focus of the ellipsoidal reflector, where the stone is located.
    [0025] Second, piezoelectric systems are based on the vibration of piezoelectric materials subjected to an electric field, commonly generated by a short high-voltage pulse between two electrodes. The expansion and compression of the piezoelectric actuators produces an ultrasonic wave that propagates to a focal point of the system, where the stones are located. When piezoelectric systems are composed of many elements, they constitute phase arrangements (also known as arrangements or “arrays”), which allow electronic focusing by means of the time lag of the electrical pulses, allowing the focal point to be dynamically positioned, just as is disclosed in JJ Rassweiler et al. previously referred to and in TG Leighton and RO Cleveland, "Lithotripsy", Proc. Inst. Mech. Eng. Part H J. Eng. Med., Vol. 224, no. 2 P. 317-342, 2010.
    [0027] Finally, electromagnetic lithotripters use an electrodynamic transducer that consists of a coil placed against a thin metallic membrane in contact with water. A high voltage pulse is discharged through a capacitor to generate a current pulsed through the coil. The subsequent pulse of current through the coil induces a repulsive force in the metallic membrane, which violently compresses the water generating an ultrasonic pulse. This process is described in detail in various references of the state of the art, for example in JJ Rassweiler et al. cited above or in W. Folberth et al., "Pressure distribution and energy flow in the focal region of two different electromagnetic shock wave sources", J. Stone Dis., vol. 4, no. 1 p.
    [0028] 1-7, 1992. Pulse focus is achieved using an acoustic lens or parabolic reflector (see previously referenced TG Leighton and RO Cleveland).
    [0030] One of the mechanisms of stone breaking is the activation of bubbles of cavitation that occurs around the stone. There are lithotripters that seek to optimize this phenomenon, for example, using simultaneous shock waves or in rapid succession, to generate the collapse of the bubbles against the stone. One strategy to achieve this is to generate, by means of a second piezoelectric head, a second shock wave confocal to the first, which allows to significantly improve the fragmentation of the stone, which is well known through the references X. Xi and P. Zhong, "Impmvement of stone fragmentation during shock-wave lithotripsy using a combined EH / PEAA shock-wave generator-in vitro experiments", Ultrasound Med. Biol., Vol. 26, no. 3, p. 457-467, 2000 and AZ Weizer et al. , "New Concepts in Shock Wave Lithotripsy", Urol. Clin. North Am., Vol. 34, no. 3, p. 375-382, 2007. Another strategy is to add an extra electrical excitation system to the lithotripter to produce two consecutive pulses, as disclosed in F. Fernández et al., "Treatment time reduction using tandem shockwaves for lithotripsy: An in vivo study" , J. Endourol., Vol. 23, no. 8, p. 1247 1253, 2009. Finally, dual-head lithotripters can deliver shock waves at the same point to optimize fragmentation, as carried out in DL Sokolov et al., “Use of a dual-pulse lithotripter to generate a localized and intensified cavitation field ”, J. Acoust. Soc. Am., Vol. 110, no. 3, p. 1685-1695, 2001 and in DL Sokolov et al., "Dual-pulse lithotripter accelerates stone fragmentation and reduces cell lysis in vitro", Ultrasound Med. Biol., Vol. 29, no. 7, p. 1045-1052, 2003 .
    [0032] Two coupling methods are commonly used between the ultrasound generation system and the patient's body. The first method, called a water bath lithotripter, partially immerses the patient's body in water, to ensure the correct transmission of shock waves into the tissues. The second method, called dry head lithotripter, consists of covering the emitter system with a water balloon and coupling it by means of an elastic membrane in contact with the patient's skin (see documents TG Leighton and RO Cleveland mentioned above). In this last technique, it is critical to ensure a correct coupling of impedances between the membrane and the skin using coupling gel. It is necessary to avoid the appearance of bubbles in the gel, which drastically decrease the effectiveness of ESWL, as demonstrated in YA Pishchalnikov et al., “A ir Pockets Trapped During Routine Coupling in Dry Head Lithotripsy Can Significantly Decrease the Delivery of Shock Wave Energy ”, J. Urol., vol. 176, no. 6, p.
    [0033] 2706-2710, 2006.
    [0035] It is known that the use of different sequences during the generation of the ultrasonic beams, as power ramps with a short pause, improves the fragmentation results of ESWL calculations, in addition to reducing tissue damage. renal. The use of slow repetition rates, around 60 waves per minute, results in optimal fragmentation with minimal complications.
    [0037] Imaging techniques such as X-ray or fluoroscopy are generally used to identify and locate the stone. This also allows the focal point of the system to be aligned on the solid to be fragmented (for example, a kidney stone) before starting ESWL treatment. However, a major drawback is stone movement relative to the lithotripter focal point during treatment. This is mainly due to the respiratory movement of the patient. If measures are not taken, this means that 50% or more of the shock waves administered do not reach the stone and affect the kidney tissue, overheating it and even damaging it. To avoid this, dynamic tracking and targeting systems have been developed using ultrasound images and piezoelectric lithotripters that continuously locate the stone and synchronize the triggering of the shock wave (see C. Bohris et al., “Hit / miss monitoring of ESWL by spectral Doppler ultrasound ”, Ultrasound Med. Biol., Vol. 29, no. 5, p. 705-712, 2003), or optics.
    [0039] Acoustic systems have recently been proposed to monitor stone fragmentation. Using a broadband receiver, the acoustic signals of the reverberation and resonance of the stones are acquired under the action of ultrasound. Various parameters such as the frequency of the acquired signals are correlated with the size of the fragment (see NR Owen et al., "The use of resonant scattering to identify stone fracture in shock wave lithotripsy", J. Acoust. Soc. Am. , vol. 121, no. 1, p. EL41-EL47, 2007). This allows the monitoring of treatment, as well as knowing when it is necessary to interrupt it and reduce unnecessary acoustic energy on healthy kidney tissue.
    [0041] However, although ESWL is widely accepted and used, this procedure has some important limitations. First, certain kidney stones are very resistant, such as brushite compounds, and their ESWL fragmentation is limited. This drawback is extremely important because patients harboring this type of stone will undergo ESWL and, therefore, will be exposed to its complications (minor and major) without the achievable benefit of fragmentation (see S. C. Kim et al., "Cystine calculi: Correlation of CT-visible structure, CT number, and stone morphology with fragmentation by shock wave lithotripsy", Urol. Res., vol. 35, no. 6, p. 319-324, 2007) .
    [0042] Stone location, size, and composition are the most important predictors of ESWL treatment success. The different types of stones, in decreasing order of hardness and therefore difficulty for their fragmentation, are formed by brushite (calcium hydrogen phosphate), cystine, calcium oxalate monohydrate, struvite, calcium oxalate dihydrate or uric acid . The type of stone can be identified by measuring radiodensity using X-ray computed tomography. Calculations with densities greater than 900 Hounsfield units (HU) anticipate possible failure of ESWL treatment (see LJ Wang et al., “Predictions of outcomes of renal stones after extracorporeal shock wave lithotripsy from stone characteristics determined by unenhanced helical computed tomography: A multivariate analysis ", Eur. Radiol., vol. 15, no. 11, p. 2238 2243, 2005). are used as predictors of stone fragmentation by ESWL. Other stones are not completely fragmented and complementary treatments are necessary, as is the frequent case of stones composed of calcium oxalate monohydrate or cystine. Finally, mainly due to the action of shock waves on healthy tissues, minor complications are very frequent, in addition to being observed in some cases complications s older (see JA McAteer et al., "Shock Wave Injury to the Kidney in SWL: Review and Perspective", p. 287-301, 2007).
    [0044] Current advances to optimize ESWL results are focused on optimizing treatment parameters, such as the initial characterization of the type, location and size of the stones (or stones), optimizing the acoustic coupling and the repetition rate of waves, as well as the sequence of shock waves.
    [0046] However, since the tissues surrounding the stone are always subjected to fragmentation by high intensity ultrasound pulses, these tissues are exposed to complications, minor or major. These complications include hemorrhages, thrombi, arrhythmias, vasoconstriction, hypertension, reduced kidney function, infections, autonomic neural system disturbances, and the release of cellular mediators and hormones. The production of tissue damage has been identified with two consecutive stages. The first stage consists of the initial rupture of the tissue due to the mechanical effects of the shock waves. This results in a pool of blood. In a second stage, said accumulation facilitates the appearance of inertial cavitation in the focal zone, producing the most damaging effects on the tissues (see previously mentioned TG Leighton and RO Cleveland documents). The appearance of inertial cavitation is closely linked to the amplitude of the rarefaction of the shock waves, that is, the minimum pressure of the pulse. Finally, excess cavitation generates gas bubbles that they act as a barrier to shock waves (see K. Maeda et al., "Energy shielding by cavitation bubble clouds in burst wave lithotripsy", J. Acoust. Soc. Am., vol. 144, no. 5, pp.
    [0047] 2952-2961, 2018). Therefore, it is necessary to quantify the cavitation that occurs, being disclosed in the field of fluid mechanics different cavitation indices.
    [0049] In addition, although patients previously experience significant pain from kidney stones, ESWL techniques also induce pain so severe that in some cases treatment must be aborted mid-procedure (see TG Leighton and RO Cleveland earlier cited). Although sources with lower focalizations (and therefore lower amplitudes of acoustic waves) are currently used to reduce pain, this aspect continues to constitute a great limitation in the state of the art.
    [0051] On the other hand, acoustic beam focusing technologies are known, as disclosed, for example, in US patent US4865042 (Unemura et al.), "Ultrasonic irradiation system", in which a system of multiple acoustic ring transducers, whose excitation signals have been conveniently offset to achieve focus on a plan two-dimensional (2D) focal zone (annular or elliptical), avoiding unwanted secondary focusing along the propagation direction. One more example Recently, regarding helical three-dimensional (3D) vortex beams, is disclosed for example in N. Jiménez et al., “Sharp acoustic vortex focusing by Fresnel-spiral zone plates”, Applied Physics Letters, 2018, vol. 112, no 20 , p 204101. The vortex beam is a longitudinal mechanical wave, of frequency typically in the ultrasound range, where the corresponding acoustic field exhibits a phase singularity along an axis. In particular, in cylindrical coordinates r = r (0, r, z) this beam can be expressed as:
    [0052] P ( d, r, z) = PoGr {r) G z ( z) exp ( iMd), (1) where P o is an arbitrary pressure value, while G r (r) and G z (z) describe the shape of the beam along the radial (r) and axial (z) coordinates respectively, M is the topological load of the beam (related to momentum transfer efficiency) and 0 is the azimuthal coordinate. The phase dislocation (typically screw type) produces a null field in the axis of the acoustic beam due to the destructive interference of the waves at that point, as illustrated in Figure 1. The maximum of the field has a distribution in annular or toroidal shape around the focus. However, the phase of the field (0) varies linearly along the azimuthal coordinate, so that the maximum pressure rotates as a function of time. This causes the vortex beams to transfer linear and angular momentum to the matter with which they interact very efficiently. In addition, they allow dosing the energy that is transferred to said matter, since they can be designed so that they are focused on a specific region and with certain physical parameters (intensity, frequency, repetition rate of the waves, etc.). In this case, these vortex beams make it possible to reach a volumetric 3D focal zone, so that simultaneously and without the need to readjust the focus (electronically or mechanically) a 3D focal zone can be reached, intentionally and controlled, that does not it is limited to a 2D plane.
    [0054] In summary, it is necessary to develop new techniques that allow efficient stone fragmentation using mechanical waves with reduced amplitudes to minimize the pain suffered by the patient, as well as the adverse effects and complications of extracorporeal shock wave lithotripsy procedures. usual.
    [0056] BRIEF DESCRIPTION OF THE INVENTION
    [0058] The present invention discloses a non-invasive solid fragmentation system using acoustic vortices. It should be noted that one of its most important applications is its use in lithotripsy.
    [0060] In a particular application, the object of the invention provides a solution to the problem of the low efficiency of ESWL techniques in terms of the amount of energy that does not end up being applied to the solids to be fragmented (for example, gallstones or kidney stones). but to the soft tissue that surrounds them. In this sense, the invention exceeds the current state of the art and provides the necessary methods and system to fragment calculi within tissues, in a non-invasive manner and using focused finite amplitude ultrasonic vortex beams, also commonly known as high intensity ultrasonic beams. However, this application is not limiting, and can be adapted for other applications that require the controlled destruction of solids in a non-invasive manner.
    [0062] In a first inventive aspect, the invention refers to a system for controlled fragmentation of solids by acoustic shock waves, comprising at least: a) an acoustic beam generation unit which, in turn, comprises:
    [0063] - a subsystem for generating electrical pulses, said pulses being characterized by a suitable voltage and / or current to produce the fragmentation of solids.
    [0064] - a first transduction subsystem, adapted to convert the electrical pulses into acoustic waves of high intensity or pressure; can be said electrohydraulic, electromagnetic, piezoelectric or similar transduction.
    [0065] - a subsystem for generating acoustic beams from the acoustic waves produced by the transduction subsystem, and for focusing said beams in a focal volume where the solid or solids to be fragmented are located.
    [0066] - an acoustic coupling subsystem, adapted to couple the acoustic beams to the solid or solids to be fragmented; and thus minimize the attenuation produced during the propagation of the acoustic waves to the focus of the system.
    [0067] - a positioning subsystem, adapted to adjust the position of the focal point. Said positioning subsystem can be electromechanical and allows the position of the focus to be adjusted automatically or manually as required by the operator or user of the system.
    [0068] b) a feedback and control unit, which allows modifying the orientation and intensity of the acoustic waves that affect the solid or solids to be fragmented and comprising:
    [0069] - a control subsystem, which controls the acoustic beam generation unit.
    [0070] - a second transduction subsystem, adapted for the acquisition of information related to the acoustic beams before and after interacting with the solid or solids.
    [0071] - a subsystem for processing the information acquired by the second transduction subsystem.
    [0073] Advantageously, in said system, the acoustic beams are vortex acoustic beams, and the feedback and control unit additionally comprises a feedback subsystem, configured to receive the information processed by the processing subsystem and send it to the control subsystem.
    [0075] In preferred embodiments of the invention, the acoustic vortex beams are ultrasonic and high intensity. Said vortex beams are focused on the calculations producing torques, shear stresses and high internal stresses that efficiently fragment said calculations. Thanks to acoustic vortices, the energy from ultrasonic excitation (in the form of longitudinal waves) is very efficiently converted into mechanical energy (as shear waves). Since the generation of shear stresses is more efficient using this type of beams, the amplitudes of the ultrasonic field necessary to fragment the stones are much lower than in current extracorporeal shock wave lithotripsy techniques, thereby reducing this In this way, unwanted effects on soft tissues such as bleeding into surrounding tissues or cavitation damage. The acoustic vortex generation technology is known and is not an intrinsic part of the patent object. In fact, multiple vortex beam configurations can serve this purpose, as long as they allow the phase displacement to be adjusted along an axis.
    [0077] In other embodiments of the invention, the feedback and control unit further comprises an image shaping subsystem; and it also comprises a monitoring subsystem of the solid or solids, which includes the means of graphical representation to offer a user of the system information on the fragmentation procedure. The image conformation system allows the solid to be monitored (location, monitoring and measurement of its position and its surroundings). In other preferred embodiments of the invention, to control the dosage of energy applied to the solid, sensors may be included to measure the temperature around the focus. In an advantageous embodiment of the invention, the monitoring subsystem comprises echo-pulse ultrasonic image shaping methods. In other embodiments of the invention, other imaging methods (fluoroscopy, X-ray, etc.) may be additionally employed, which may in turn require other transduction mechanisms. Thanks to the monitoring subsystem, the user of the system can monitor the treatment and decide to interrupt it if necessary (for example, if the patient reports pain or if the amplitude of the acoustic waves is excessive).
    [0079] In some preferred embodiments of the invention, the information processing subsystem comprises real-time measurements of the cavitation that occurs around the focal point, and where additionally the feedback subsystem takes into account, at least, the evolution or the state of said cavitation, to readjust the physical parameters that describe the acoustic beams that affect the focus. For example, if cavitation is excessive, then the amplitude or repetition rate of the acoustic beams can be reduced.
    [0081] In some particular embodiments of the invention, the first electromechanical transduction subsystem is of the electrohydraulic type, and the acoustic beam generation subsystem comprises a reflector with a helicoelipsoidal surface for generating the vortex in reflection. In this case, the positioning subsystem is of a mechanical type and is responsible for aligning the focus of the system with the solid to be fragmented.
    [0083] In other preferred embodiments of the invention, the first transduction subsystem it is of the electromagnetic type, and the acoustic beam generation subsystem comprises a helical parabolic reflector. Additionally, in said embodiments, the positioning subsystem is preferably of the mechanical type, and serves to align the focus of the system with the solid to be fragmented.
    [0085] In other advantageous embodiments of the invention, the first transduction subsystem is of the electromagnetic type, while the acoustic beam generation subsystem comprises an acoustic lens. Such a lens requires a mechanical positioning subsystem for focus adjustment. In still other more advantageous embodiments, the acoustic lens has a helical or helicalipsoidal phase profile.
    [0087] In another particular implementation of the invention, the first transduction subsystem for generating the beams is of the piezoelectric type. In this case, the acoustic beam generation subsystem comprises a multi-element phase arrangement immersed in a fluid. Unlike the previous particular embodiments, the positioning system is preferably electronic, and allows setting the delays applied to the excitation signal of each of the channels of the phase arrangement, to readjust the position of the focus of the system without necessity. of a mechanical alignment.
    [0089] In a further embodiment of the invention, the first transduction subsystem comprises a single piezoelectric transducer immersed in a fluid, the arrangement of said transducer on a helical surface that provides the acoustic beam generation subsystem; said system additionally comprising a mechanical type positioning subsystem to adjust the focal point of the system.
    [0091] Another additional embodiment of the invention consists in replacing, in the previous embodiment, the single transducer by a multi-element piezoelectric transducer, where each element is arranged on the helical spheroidal surface. Thus, in this embodiment, the first transduction subsystem comprises a multi-element piezoelectric transducer immersed in a fluid, the arrangement of each of its channels on a helical surface being the one that provides the acoustic beam generation and focusing subsystem; said system additionally comprising a mechanical type positioning subsystem to adjust the focal point of the system.
    [0093] Another preferred embodiment of the invention includes a first piezoelectric type transduction subsystem for generating acoustic waves where, additionally, the acoustic beam generation (and focusing) subsystem comprises an acoustic lens. In In some even more advantageous embodiments, said acoustic lens may have a helical or helicalipsoidal phase profile.
    [0095] A preferred use of the solid fragmentation system is its application in the field of lithotripsy.
    [0097] In a further preferred embodiment of the invention, the feedback and control unit comprises a plurality of actuators to readjust the focus of the system according to the movement of the patient. For example, to compensate for focus misalignment introduced by the patient's breathing. In such a case, the actuators may be pressure pads, abdominal pneumatic sensors, tracheal breath sound monitors, or analogous sensors for detecting respiration. This focus realignment is preferably carried out in real time.
    [0099] In the scope of the invention, phase arrays, arrangements or arrays are preferably understood as an array of acoustic transducers where each element can be adjusted to emit a beam with certain physical characteristics (amplitude, frequency, phase, etc.). The transducers, in turn, can be single-element (a single transducer) or divided into multiple elements (also known as sectors or channels), each of which acts as an independent transducer. In turn, an acoustic lens is understood to be a device capable of focusing sound in a similar way to how an optical lens focuses light.
    [0101] In the context of the invention, the acoustic waves once shaped and oriented towards the position where they are to act will be called acoustic beams. An acoustic beam refers to the already shaped acoustic wave.
    [0103] Furthermore, a vortex beam is understood to be that acoustic beam, either two-dimensional or three-dimensional, whose acoustic field has a phase dislocation along an axis (referred to as the 'propagation axis'). Thus, a 2D vortex beam could be annular or ellipsoidal in shape, while a 3D beam could be helical in shape. The area in which said beam is focused is a focal volume, in 3D, that extends along the direction of propagation of the beam. The focus of the system will preferably be understood as a region corresponding substantially to the centroid of said focal volume. Within the scope of the invention, the expression "substantially" shall also be understood as identical, or included in a variation range of ± 15%.
    [0104] DESCRIPTION OF THE DRAWINGS
    [0106] To complement the description of the invention, a set of figures is provided that form an integral part of the description and illustrate various preferred implementations of the invention. However, they should not be understood as limiting the scope of the invention, but only as different examples of how it can be carried out.
    [0108] Figure 1 shows the acoustic field of a focused vortex beam: (a) absolute value of the normalized acoustic field, denoted as | P | / P0, in a sagittal section P (x, y = 0, z). (b) phase $ of the acoustic field in a sagittal section. (c) absolute value of the normalized acoustic field in a cross section over the focal zone, P (x, y, z = F). (d) phase of the acoustic field in a cross section to the focal zone.
    [0110] Figure 2 shows a diagram of the system for fragmentation of solids using acoustic (ultrasonic) vortices that is the object of the invention, for its application in lithotripsy.
    [0112] Figure 3 represents a diagram of a preferred implementation of the invention, where the acoustic beam generation subsystem (3) is of the electrohydraulic type and comprises a helical reflector. The vortex beams (13) are oriented towards the focal point (14) of the system, which coincides with the position of the solid (in this case, a kidney stone) to be fragmented.
    [0114] Figure 4 illustrates in more detail the helical reflector used to generate and focus the vortex beams of Figure 3.
    [0116] Figure 5 represents a diagram of a preferred implementation of the system of the invention, which comprises a subsystem (3) for generating acoustic beams of the electromagnetic type and includes a helical parabolic reflector. The vortex beams (13) are oriented towards the focal point (14) of the system, which coincides with the position of the solid to be fragmented.
    [0118] Figure 6 includes a detailed diagram of the structure of the helical parabolic reflector referred to in Figure 5 and which is used for the acoustic beam generation subsystem (3), which is of the electromagnetic type.
    [0119] Figure 7 shows an implementation of the system of the invention, whose vortex generator is of the electromagnetic type and includes a helical phase acoustic lens acting as a subsystem (3) for generating acoustic beams. The vortex beams (13) are oriented towards the focal point (14) of the system, which coincides with the position of the solid to be fragmented.
    [0121] Figure 8 includes a detailed diagram of the helical phase acoustic lens for the electromagnetic vortex generating system referred to in Figure 7, which focuses on focal point F.
    [0123] Figure 9 illustrates a preferred implementation where the vortex generator comprises a multi-element piezoelectric transducer in phase arrangement configuration as electromechanical transduction subsystem (2). The vortex beams (13) are oriented towards the focal point (14) of the system, which coincides with the position of the solid to be fragmented.
    [0125] Figure 10 shows a detailed diagram of the piezoelectric vortex generation subsystem using the phase arrangement referred to in Figure 9.
    [0127] Figure 11 shows a particular implementation where the electromechanical transduction subsystem (2) comprises a single element helical spheroidal piezoelectric transducer with spherical focusing. The vortex beams (13) are oriented towards the focal point (14) of the system, which coincides with the position of the solid to be fragmented.
    [0129] Figure 12 shows a detailed diagram of the spherical focusing single element helical spheroidal piezoelectric transducer referred to in Figure 11.
    [0131] Figure 13 illustrates a particular implementation where the electromechanical type transduction subsystem (2) is implemented by means of a multiple element helical spheroidal piezoelectric transducer with spherical focusing. The vortex beams (13) are oriented towards the focal point (14) of the system, which coincides with the position of the solid to be fragmented.
    [0133] Figure 14 shows a detailed diagram of the piezoelectric vortex generation subsystem by means of a multiple element with spherical focusing arranged on a helical surface (15).
    [0134] Numerical references used in the drawings:
    [0139] DETAILED DESCRIPTION OF THE INVENTION
    [0141] Figure 2 shows a preferred embodiment of the solids fragmentation system of the invention. Said system preferably comprises at least two units: a unit (100) for generating acoustic, preferably ultrasonic and high intensity beams, and a unit (200) for feedback and control.
    [0143] In the first place, the acoustic beam generation unit (100) is responsible for the production of acoustic beams, preferably ultrasonic, and for orienting them appropriately in the area where the stone is located, in order to produce their fragmentation. This unit (100) is made up of at least the following subsystems:
    [0144] - an electronic power generation subsystem (1), adapted to generate high voltage and / or current electrical pulses.
    [0145] - a first transduction subsystem (2) (preferably electromechanical) for converting the electrical pulses provided by the generation subsystem (1) into high intensity ultrasonic waves.
    [0146] - a subsystem (3) for generating acoustic beams, responsible for generating and orienting one or more vortex beams from the ultrasonic waves obtained in the first transduction subsystem (2).
    [0147] - an acoustic coupling subsystem (4) between the acoustic beam generation unit (100) and the object to be fragmented (for example, a stone inside the patient's body), to minimize the attenuation of the ultrasonic waves that constitute the vortices during its propagation, which has a very negative impact on the efficiency of the treatment (6).
    [0148] - a positioning subsystem (5), either electronic or mechanical, which allows aligning the focus of the beams formed and focused by the acoustic beam generation subsystem (3), and thus affect the location where the calculation is located. fragment.
    [0150] Once the acoustic beam generation unit (100) is configured, the treatment (6) is applied, which consists of directing the acoustic waves towards the solid to be fragmented.
    [0152] Regarding the treatment feedback and control unit (200), it is in charge of acquiring information on the position, characteristics and state of the calculation before, during and / or after the treatment (6). Based on the estimation of the position of the calculation and its size, the unit (200) provides the control signals that allow adjusting the position of the focal position (14) of the system and, where appropriate, other parameters of the vortex (topological load , etc.). In general, unit (200) consists of at least these elements:
    [0153] - a control subsystem (7) of the ultrasonic vortex beam generation subsystem (3), configured to modify the physical parameters of the beams (amplitude, intensity, frequency, etc.) by manipulating one or more of the subsystems (1, 2, 3, 4, 5) of the acoustic beam generation unit (100). Said subsystem (7) must allow the voluntary interruption of treatment by the system operator (for example, if the patient reports excessive pain), or the automatic stopping of the electrical pulse generation subsystem (1) if any critical threshold (either an excess of temperature in the surroundings of the treated area or an excessively high cavitation index).
    [0154] - a second electromechanical transduction subsystem (8) configured to acquire signals from the acoustic beams before, during, and / or after the treatment.
    [0155] - a subsystem (9) for shaping images of the solid to be fragmented, and / or its surroundings. Preferably the images are ultrasonic.
    [0156] - a subsystem (10) for monitoring the treatment, preferably in real time, comprising a monitor or any means of graphic representation that offers information about the treatment to the operator who manipulates the system and, in particular, that shows the images of the solid and other parameters of interest derived from them. The solid tracking information (calculation) provided by the monitoring subsystem (10) is used to adjust the focus of the high intensity acoustic beam generating unit (100).
    [0157] - a subsystem (11) for processing the acquired information, including the means that allow analyzing its energy in different frequency bands of interest, in order to evaluate the effectiveness of the treatment (6) in real time (for example, calculating various indices cavitation or other analogous parameters that could be relevant to predict risks of serious complications during treatment), so that this information also appears on the monitor or means of graphic representation of the monitoring subsystem (10).
    [0158] - A feedback subsystem (12) that, depending on the follow-up of the calculation made by the monitoring subsystem (10), of the information extracted by the information processing subsystem (11) (ultrasonic signals, etc.) and / or other measurements (for example, temperature increase in the vicinity of the area where the beam is focused), indicate to the control subsystem (7) the need to adjust the beams (for example, through modifications of the amplitude , frequency and repetition rate of the electrical pulse generation subsystem (1), etc.).
    [0160] The elements within each subsystem (1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12) are preferably interconnected as illustrated in Figure 2.
    [0162] It should be noted that the feedback and control unit (200) and, in particular, the acquired information processing subsystem (11), are in charge of calculating different acoustic indices that modulate the feedback subsystem (12), which, at in turn, it communicates to the control subsystem (7) the modifications that must be made in the pulse generation subsystem. Said indices modulate, preferably in real time, the intensity of the pulses and, consequently, the amplitude of the ultrasonic waves and the repetition rate of the pulses. To this end, the system calculates the cavitation indices by integrating the energy of the acquired signals and filtering over different bandwidths. The parameters defined below are not exclusive, and one of ordinary skill in the art could define other analogous parameters. In particular, these indices Acoustics are obtained from the Fourier transform of the acoustic signal, denoted by P (w).
    [0164] First, the stable cavitation index is defined as Isc = ^ I n = 2lP (nM0) l2, where wo is the fundamental frequency of the ultrasonic emission (either the fundamental frequency of a sinusoidal burst or the center frequency of the pulses in the case of pulsed excitation) and N = Wmax / wo, where Wmax is the maximum frequency allowed by the bandwidth of the acquisition system.
    [0166] The subharmonic cavitation index (I sh ) is calculated from the power spectrum of the
    [0167] subharmonic component, that is, ISH = | p (^ 2) | . The ultra-harmonic cavitation index (I uh ) is calculated by integrating the power spectrum of all ultra-harmonics in the
    [0168] fundamental frequency, that is, IUH = - U = 2 | P (- ^ —w0JI.
    [0170] The inertial cavitation index (I ic ) is calculated by integrating the entire spectrum of the acoustic signal and subtracting the power spectrum of the harmonics from the fundamental frequency, as follows:
    [0172] In this way, the signals of the cavitation indices vary as a function of the cavitation activity around the focal point (14), where the stone to be fragmented is preferably located. These indices are used to modulate the control signals of the power generation system through the acoustic feedback system. The indices are also displayed through a graphic interface for real-time monitoring of treatment (6) and providing relevant information for follow-up and / or voluntary interruption of treatment (6).
    [0174] In the following, various preferred implementations of the acoustic beam generating unit 100 are described.
    [0176] A preferred implementation of the invention is shown in Figure 3, where the electrical pulse generation subsystem (1) electrically excites an immersed spark plug in a fluid, which acts as a first electrohydraulic transduction subsystem (2). After subjecting the spark plug to a certain voltage, the dielectric breaks, generating an electric arc between its terminals. In this way, a high current of electrons is induced to flow between the two terminals, which translates into a momentary increase in the temperature of the fluid. In turn, the increase in temperature generates gas bubbles that expand violently and then compress under the hydrodynamic pressure of the rest of the fluid. This process produces a spherical, transient acoustic wave with a high pressure amplitude that propagates throughout the fluid. The system comprises a reflector with a helicoelipsoidal surface as a subsystem (3) for generating acoustic beams, in charge of reflecting said wave front towards the position of the stone to be fragmented. Due to the particularities of the helicoelipsoidal reflector, the vortex beam is generated in reflection and the wavefront is focused on the focal point F 2 , according to the coordinate system shown in Figure 4, where the fragmentation of the stones will occur. . To ensure optimal transmission of said wavefront, the system uses an acoustic coupling subsystem (4), which can be a water balloon coupled to the patient's skin by means of an elastic membrane, a coupling gel layer or a water bath. . It should be noted that the helical reflector is arranged on a helical surface capable of providing a difference in acoustic delays (At) as a function of the azimuthal coordinate (0) equal to:
    [0178]
    [0179] where w o is the design angular frequency and M is the topological load of the beam. Since the beam propagates in a fluid in which a constant speed of propagation can be assumed, these delays are generated when the difference in acoustic paths (AL) is equal to:
    [0180] AL (0) = (MA o 0) / 2n, (3) where A o = 2nc o / w o is the design wavelength and c o is the speed of sound in the fluid. If we define an elliptic curve with foci F i and F 2 , and an ellipsoid constant a p (0) = [2a-AL (0)] / 2, where a is the largest of the minor semi-axes of the helical reflector, can define the semi-axes (b x and b y ) of the reflector surface in
    [0181] azimuth coordinate function, bx (0) = and by (0) =.
    [0182]
    [0183] Finally, the surface of the helical reflector at a point r = r (x, y, z) is given by F 2 :
    [0184] x (0, $) = b x (0) cos (0) sin ($), (4) y (0, $) = b y (0) sin (0) sinfl), (5) z (0, $) = - F 2 -a p (0) cosfl), (6) where in Equations (4-6) the azimuth angle 0 is between 0 and 2n, and following the convention, the elevation angle 0 is between 0 and n. If we also consider that the semi-axes of the reflector geometrically limit its aperture (A), A <2a, then the maximum elevation is given by 0 max = tan -1 (A / 2F 2 ) while the diameter of the central hole (A h ) between the electrohydraulic electrical pulse generation subsystem (1) and the second transduction subsystem (8) used for monitoring the treatment (6), determines that the minimum elevation is given by 0 min = tan -1 (A h / 2F 2 ). At very low frequency the reflector acts as an elliptical reflector since the phase difference is very low. Therefore, both at low and high frequencies the helical reflector ensures that all the acoustic energy is focused on the focus F 2 . Since the position of the focus cannot be controlled electronically and is fixed by the focus of the helical reflector, a mechanical movement system is required to align the focal point (14), F 2 , with the calculation. The main drawback of this implementation is its reduced useful life, due to the erosion of the spark plugs due to use.
    [0186] In a preferred alternative implementation, the high amplitude ultrasonic (vortex) acoustic (vortex) beam generation subsystem (3) requires the prior action of a first electromagnetic type transduction subsystem (2), and comprises a helical parabolic reflector to the generation and focusing of the beam, as shown in Figure 5. In this way, the system uses a subsystem (1) for generating high current electrical pulses to electrically excite by means of a coil attached to an immersed mobile elastic cylinder. in a fluid and located on the axial axis of the system. Analogous to electromechanical transducers in dynamic speakers, coil induction generates a force that first expands and then compresses the cylinder. Said electromagnetic transduction process produces a high amplitude, transient, cylindrical pressure acoustic wave front, which propagates along the fluid over the radial coordinate, perpendicular to the axial axis of the system. The reflector with a helical parabolic surface is used to redirect said wave front over the focal point (14), called F hereinafter, where stone fragmentation will occur. The acoustic coupling subsystem (4) can be, among others, a water balloon coupled to the patient's skin by means of an elastic membrane, a coupling gel layer or a water bath. It should be noted that the design of the reflector (represented in Figure 6) simultaneously guarantees the focusing of the wavefront on the focal point and that a phase dislocation occurs on that point. For this, the difference in acoustic paths must meet the conditions of Equations (2-3). The reflector design is made considering a helical parabolic surface, formed by a parabolic profile whose focus is fixed at the point r (0, r, z) = (O, O, F). Parabolic profiles intersect the lower plane of the system located at z = 0 at the point r (0, r, z) = (0, r c (0), O), where the coordinate rc (0) = R m - (m'M0A o / 2n), R m is an initial radius and m 'a factor necessary to align the phases and compensate for the curvature of the paraboloid. If the approximation is used:
    [0188]
    [0189] then the phase alignment of the wavefront will present an error of less than 1%. A more precise approximation is possible, using a series expansion to higher orders or by means of numerical techniques. The helical parabolic surface has as its vertex the point r (0, r, z) = (O, -1 / 4a (0), F), where:
    [0191]
    [0194] In representation under cylindrical coordinates r = r (0, r, z), the reflector surface is defined as:
    [0196]
    [0197] where O <0 <2n and 0 <z <z max , where Z max is the height of the cylindrical electromagnetic generator. Since the position of the focus cannot be controlled electronically and is fixed by the focus of the helical parabolic reflector, this implementation also requires a mechanical system to align the focus point (14) with the stone to be fragmented.
    [0199] In another preferred implementation, the generation of high intensity vortices comprises a first transduction subsystem (2) of the electromagnetic type with a flat surface and a circular or annular shape coupled to a helical phase lens, as illustrated in Figure 7. The system uses a subsystem (1) for generating high current electrical pulses to electrically excite a coil attached to a moving, circular or annular surface, which on one of its faces is in contact with a fluid. The induction of the coil generates a force that transiently displaces the circular or annular surface in the axial direction. This process produces a flat, transient acoustic wave front with a high pressure amplitude, which propagates along the fluid along the axial axis of the system. The system uses a helical phase lens to control the wavefront, which is generated in transmission (without the need for reflectors as previous implementations) and is focused on a focal point (F) where stone fragmentation will occur. Figure 8 shows an acoustic lens model based on the refraction of acoustic waves when passing through a medium whose speed of sound propagation is different from that experienced in the fluid. When the lens material has a velocity of propagation (c n ) greater than the velocity of propagation in the fluid (co), then the lens is double concave. This case occurs when the fluid is water and the lens material (for example, metals, plastics, or polymers) is solid. Otherwise, when the lens material has a propagation speed lower than that of the fluid, the lens is double convex. Said lens is formed by a spherical surface on its first face and a helicoelipsoidal surface on the second. The acoustic lens design is detailed below. The helicoelipsoidal surface can be defined in cylindrical coordinates by an elliptical profile of revolution whose parameters vary as a function of the azimuthal angle 0. The eccentricity (£) of said elliptical profiles is constant, and is given by £ = co / cn; while the focus of the profiles is given by:
    [0201]
    [0202] where F is the geometric focus of the lens and m ', in this case, has a value close to unity and can be calculated numerically. Finally, if we take into account that the semi-major axis of the helical surface is given by a (0) = c (0) / £ and the semi-axis
    [0203] smaller by b (0) = c (0) the surface of the helical lens is given by:
    [0204]
    [0206]
    [0209] The other face of the lens, the spherical one, is given by the surface:
    [0211]
    [0212] where the radius of curvature is R c = (F s + Az) (1- £), where F s is the focal length of the concave lens and Az is its thickness on the axial axis. The use of a spherical lens on the underside is optional, but reduces the limitations on the maximum aperture of the helical lens. For example, using a lens with a focal length F s = 4F, the system makes it possible to produce large aperture vortex generators and, therefore, higher acoustic intensities in the focal zone. Since the position of the focus cannot be controlled electronically and is fixed by the helical phase acoustic lens, a mechanical system is required to align the focal point (14) with the calculation.
    [0214] In another preferred embodiment, the high intensity acoustic beam generation subsystem (3) comprises a multi-element piezoelectric system configured as a phase arrangement, as seen in Figure 9. The system uses a generation subsystem (1) of multi-channel high voltage electrical pulses to electrically drive a series of piezoelectric transducers arranged on a spherical surface and immersed in a fluid. Under the action of the transient electric field, the piezoelectric transducers that constitute the first transduction subsystem (2) deform, compressing and expanding the fluid and generating a focused, transient and high-amplitude acoustic wave front of high pressure, which converges towards the center of the spherical surface. The radius of the spherical surface coincides with the focal point (14) of the system where stone fragmentation will occur. The shape of the piezoelectric elements can be sectorial, circular, or hexagonal, among others; as well as its arrangement on the spherical surface, which preferably follows a regular pattern in polar coordinates or any other, periodic or not. Assuming that the piezoelectric elements of the phase arrangement are equally spaced in polar coordinates, to control the wave front and generate the acoustic vortex, a series of delays must be applied to each of the voltage pulses of the phase arrangement shown in detail in the Figure 10. The value of each delay ( t ) depends on the 0 position of each piezoelectric element and is given by
    [0215] t = (M 0) / w o . In this way, this phase arrangement makes it possible to move the focal point F of the system, delaying each of the channels of the electronic excitation system until the beams align in phase. With this configuration, if you want to move the vortex to a point r p (x, y, z) = (F x , F y , F z ), the delays that must be applied to each of the elements of the phase array ( which are centered on a point r or (x, y, z)) are calculated as:
    [0216] \ rF {x, y, z) - r 0 (or :, and Z)
    [0217] A * (ro, r F) =
    [0218] cq + t {8), (13) although for a phase arrangement arranged on a spherical surface the previous expression is reduced
    [0220] The piezoelectric system allows the generation of long-term excitation signals, where the phases are given by a complex coefficient ^ (ro, rp) = exp (iwoAt), where the term woAt is used to delay signals or sinusoidal bursts when the excitation is not transitory. This process allows the fragmentation of the stones striking with beams of smaller amplitude, which mitigates the unwanted effects of the treatment.
    [0222] Another particularly advantageous embodiment is the one shown in Figure 11, which constitutes a variant of the system referred to in Figure 9. Since phase arrangements require electronic control of the delays applied to each channel (which adds complexity to the design), the design in Figure 11 employs a single high voltage electrical pulse generation subsystem (1) that drives a first transduction subsystem (2) formed by a single piezoelectric transducer. The surface of the piezoelectric is helical, as illustrated in Figure 12, and can be expressed as the azimuth revolution of a circumferential arc section where the radius of curvature of said arc, R c (0), is given by:
    [0224] Rc ( 0) = F - 2 R * (15) in such a way that thanks to said curvature a path difference is generated between the beams at the design frequency wo = 2nco / Ao, which produces a topological load vortex M For the design of the helical surface, its definition in spherical coordinates r = r (0, $, r) is taken into account, which is given by
    [0225] x (0, $) = R c (0) cos (0) sin ($), (16) y (0, $) = R c (0) sin (0) sin ($), (17) z ( 0, $) = -F 2 -R c (0) cos ($), (18) where O <0 <2n and the minimum and maximum limits of the elevation angles are given by 0min = tan-1 (Ah / 2F2) and 0max = tan-1 (A / 2F2), where A is the opening of the transducer and Ah is the diameter of the lower hole, which can be zero. The subsystem (3) for generating piezoelectric acoustic beams by means of a single element transducer with a helical surface has a vortex at the focal point (14) whose position cannot be controlled, so as with electro-hydraulic generators and electromagnetic, a mechanical positioning subsystem (5) is required to align the focal point with the calculus to be fragmented.
    [0227] An even more advantageous embodiment of the invention comprises a first transduction subsystem (2) formed by multiple piezoelectric elements arranged on a helical surface, as shown in Figure 13. In this way, the complications associated with manufacturing are avoided. of a single piezoelectric transducer with helical surface, as shown previously in Figures 11 and 12. The multiple piezoelectric elements (transducers) represented in Figure 13 can be driven by a single electrical signal, which reduces cost and complexity of the system compared to the phase array system of Figures 11-12. The subsystem (3) for generating piezoelectric type acoustic beams by means of a multiple element transducer with a helical surface presents a vortex at the focal point (14) whose position cannot be controlled if the same signal is used for all the elements, for what is required of a subsystem (5) of mechanical positioning to align the focal point (14) with the calculation. The detail of the curvature of the helical surface is shown in Figure 14 and is described by Equations (15-18). The shape of the multiple piezoelectric elements can be sectorial, or any other (circular, hexagonal, etc.).
    [0228] Additionally, another preferred embodiment of the invention comprises a first piezoelectric transduction subsystem (2) whose transducers can be single or multiple element, and additionally comprises a helical phase acoustic lens to produce the focused vortices. The acoustic lens is placed on the piezoelectric transducer (s), each of which is excited with a high voltage pulsed or sinusoidal signal. The use of the acoustic lens allows the control of the focus of the beam, and, simultaneously, the generation of the vortex with arbitrary topological load without the need to use a multi-channel electronic device to excite each one of the elements individually. Since the lens is a removable and easily interchangeable component of the system, multiple lenses can be interchanged to adjust the focal length, topological load, design frequency and beam width, thereby adjusting the characteristics of the acoustic focus. to the treatment to be carried out. The lens design is given by Equations (10-12). In the event that the piezoelectric system is arranged on a flat circular surface, the lens will be flat on its underside. Since the focal point (14) cannot be controlled electronically if the same signal is used for all piezoelectric elements or if a single piezoelectric element is used, and it is fixed by the lens, a mechanical movement system is required to align the focal point with the calculation.
    [0230] In the implementations in which the acoustic beam generation unit (100) involves electrohydraulic, electromagnetic or piezoelectric transducers (either single or multiple element), the mechanical positioning subsystem (5) comprises at least one actuator that allows realignment of the focal point (14) of the system.
    [0232] Various preferred implementations of the feedback and control unit 200 are discussed below.
    [0234] In a preferred implementation of the invention, the second electromechanical transduction subsystem (8) comprises a phase array of piezoelectric transducers, to provide an ultrasound imaging subsystem (9) in echo-pulse mode.
    [0236] In another even more advantageous implementation, the treatment monitoring subsystem (10) additionally comprises the means for recording in real time the natural movements of the patient (for example, breathing) and comprises at least one motion sensor. The recorded data is used by the control subsystem (7) to automatically correct the misalignment of the focal point (14) of the system. due to movement (voluntary or involuntary) of the patient.
    [0238] In some alternative embodiments of the invention, the feedback and control unit 200 may be dispensed with. Such solutions are considered suboptimal because they would not allow continuous monitoring and modulation of the ultrasonic treatment; as well as they would require applying a predefined sequence of electrical pulses, to then interrupt the treatment and acquire some type of image (by X-rays, ultrasounds, etc.) that allows evaluating the results of the same.
    权利要求:
    Claims (15)
    [1]

    [2]
    two.
    [3]
    3.
    [4]
    Four.
    [5]
    5.
    [6]
    6.
    [7]
    7.
    [8]

    [9]
    9.
    [10]
    10.
    [11]
    eleven.
    [12]
    12.
    [13]
    13.
    [14]
    14.
    [15]
    fifteen. System according to the preceding claim wherein the feedback and control unit (200) comprises a plurality of actuators to readjust the focal point (14) of said system.
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    同族专利:
    公开号 | 公开日
    WO2022018311A1|2022-01-27|
    ES2811092B2|2021-04-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4865042A|1985-08-16|1989-09-12|Hitachi, Ltd.|Ultrasonic irradiation system|
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    WO2004089188A2|2003-03-31|2004-10-21|Liposonix, Inc.|Vortex transducer|
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    PCT/ES2021/070524| WO2022018311A1|2020-07-20|2021-07-15|System for the controlled fragmentation of solids by means of vortex sound beams|
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