METHOD AND SYSTEM FOR NONINVASIVE FACE LIFTS AND DEEP TISSUE TIGHTENING

[0001] This application is a continuation-in-part of and claims priority to and benefit of U.S. application Ser. No. 11/163,151 entitled “Method and System for Noninvasive Face Lifts and Deep Tissue Tightening” filed on Oct. 6, 2005 which in turn claims priority to U.S. Provisional Application No. 60/616,755 entitled “Method and System for Noninvasive Face Lifts and Deep Tissue Tightening” filed on Oct. 6, 2004. Further, this application claims priority to U.S. application Ser. No. 11/163,148 entitled “Method and System for Controlled Thermal Injury of Human Superficial Tissue” filed on Oct. 6, 2005 which in turn claims priority to U.S. Provisional Application No. 60/616,754 entitled “Method and System for Controlled Thermal Injury of Human Superficial Tissue” filed on Oct. 6, 2004.

[0002] The present invention relates to ultrasound therapy and imaging systems, and in particular to a method and system for noninvasive face lifts and deep tissue tightening.

[0003] Coarse sagging of the skin and facial musculature occurs gradually over time due to gravity and chronic changes in connective tissue generally associated with aging. Invasive surgical treatment to tighten such tissues is common, for example by facelift procedures. In these treatments for connective tissue sagging, a portion of the tissue is usually removed, and sutures or other fasteners are used to suspend the sagging tissue structures. On the face, the Superficial Muscular Aponeurosis System (SMAS) forms a continuous layer superficial to the muscles of facial expression and beneath the skin and subcutaneous fat. Conventional face lift operations involve suspension of the SMAS through such suture and fastener procedures.

[0004] No present procedures have been developed yet, which provide the combination of targeted, precise, local heating to a specified temperature region capable of inducing ablation (thermal injury) to underlying skin and subcutaneous fat. Attempts have included the use of radio frequency (RF) devices that have been used to produce heating and shrinkage of skin on the face with some limited success as a non-invasive alternative to surgical lifting procedures. However, RF is a dispersive form of energy deposition. RF energy is impossible to control precisely within the heated tissue volume and depth, because resistive heating of tissues by RF energy occurs along the entire path of electrical conduction through tissues. Another restriction of RF energy for non-invasive tightening of the SMAS is unwanted destruction of the overlying fat and skin layers. The electric impedance to RF within fat, overlying the suspensory connective structures intended for shrinking, leads to higher temperatures in the fat than in the target suspensory structures. Similarly, mid-infrared lasers and other light sources have been used to non-invasively heat and shrink connective tissues of the dermis, again with limited success. However, light is not capable of non-invasive treatment of SMAS because light does not penetrate deeply enough to produce local heating there. Below a depth of approximately 1 mm, light energy is multiply scattered and cannot be focused to achieve precise local heating.

[0005] A method and system for noninvasive face lifts and deep tissue tightening are provided. An exemplary method and treatment system are configured for the imaging, monitoring, and thermal injury to treat the SMAS region. In accordance with an exemplary embodiment, the exemplary method and system are configured for treating the SMAS region by first, imaging of the region of interest for localization of the treatment area and surrounding structures, second, delivery of ultrasound energy at a depth, distribution, timing, and energy level to achieve the desired therapeutic effect, and third to monitor the treatment area before, during, and after therapy to plan and assess the results and/or provide feedback.

[0006] In accordance with an exemplary embodiment, an exemplary treatment system comprises an imaging/therapy probe, a control system and display system. The imaging/therapy probe can comprise various probe and/or transducer configurations. For example, the probe can be configured for a combined dual-mode imaging/therapy transducer, coupled or co-housed imaging/therapy transducers, or simply a therapy probe and an imaging probe. The control system and display system can also comprise various configurations for controlling probe and system functionality, including for example a microprocessor with software and a plurality of input/output devices, a system for controlling electronic and/or mechanical scanning and/or multiplexing of transducers, a system for power delivery, systems for monitoring, systems for sensing the spatial position of the probe and/or transducers, and systems for handling user input and recording treatment results, among others.

[0007] In accordance with an exemplary embodiment, ultrasound imaging can be utilized for safety purposes, such as to avoid injuring vital structures such as the facial nerve (motor nerve), parotid gland, facial artery, and trigeminal nerve (for sensory functions) among others. For example, ultrasound imaging can be used to identify SMAS as the superficial layer well defined by echoes overlying the facial muscles. Such muscles can be readily seen and better identified by moving them, and their image may be further enhanced via signal and image processing.

[0008] In accordance with an exemplary embodiment, ultrasound therapy via focused ultrasound, an array of foci, a locus of foci, a line focus, and/or diffraction patterns from single element, multiple elements, annular array, one-, two-, or three-dimensional arrays, broadband transducers, and/or combinations thereof, with or without lenses, acoustic components, mechanical and/or electronic focusing are utilized to treat the SMAS region at fixed and/or variable depth or dynamically controllable depths and positions.

[0009] In accordance with another exemplary embodiment, a therapeutic treatment method and system for controlled thermal injury of human superficial tissue is based on the ability to controllably create thermal lesions of a variable shape, size, and depth through precise spatial and temporal control of acoustic energy deposition. This system and method for controlled thermal injury can be used to complete various procedures such as face lifts and deep tissue tightening described herein. In accordance with an exemplary embodiment, an exemplary therapeutic treatment system includes a control system and a probe system that can facilitate treatment planning, controlling and/or delivering of acoustic energy, and/or monitoring of treatment conditions to a region of interest. As a result, the ability to controllably produce conformal lesions of thermal injury in superficial human tissue can be realized.

[0010] In accordance with another exemplary embodiment, a treatment method can enable the regions of thermal injury to comprise controlled conformal shapes and sizes and allow the tissue to be destroyed (ablated) in a controlled spatial and temporal manner. For example, the thermal lesions may be suitably and selectively created with narrow or wide lateral extent, long or short axial length, and/or deep or shallow placement, including up to the tissue outer surface. Moreover, separate islands of destruction may also be created over part or whole of the tissue region-of-interest, and/or contiguous or overlapping structures may be produced out of discrete lesions.

[0011] In accordance with other exemplary embodiments of the present invention, exemplary methods can comprise scanning over part or whole of the region-of-interest to produce contiguous thermal injury. The conformal lesions can be achieved not only through the independent selection and control of transducer acoustic energy spatial distribution, such as selection of transducer configuration and placement, but also through temporal control, such as through drive amplitude levels, frequency/waveform selection, and timing sequences that can be adjusted and optimized to control thermal ablation of tissue. In addition, the temperature at the acoustic coupling interface can be controlled, thus further enabling another exemplary method of lesion formation control.

[0030] The present invention may be described herein in terms of various functional components and processing steps. It should be appreciated that such components and steps may be realized by any number of hardware components configured to perform the specified functions. For example, the present invention may employ various medical treatment devices, visual imaging and display devices, input terminals and the like, which may carry out a variety of functions under the control of one or more control systems or other control devices. In addition, the present invention may be practiced in any number of medical contexts and that the exemplary embodiments relating to a method and system for noninvasive face lift and deep tissue tightening as described herein are merely indicative of exemplary applications for the invention. For example, the principles, features and methods discussed may be applied to any SMAS-like muscular fascia, such as platysma, temporal fascia, and/or occipital fascia, or any other medical application.

[0031] Further, various aspects of the present invention may be suitably applied to other applications. The system and method of the present invention may also be used for controlled thermal injury of various tissue. Certain exemplary methods for controlled thermal injury to various tissues are disclosed in co-pending U.S. patent application Ser. No. 11/163,148 entitled “Method and System for Controlled Thermal Injury of Human Superficial Tissue” filed on Oct. 5, 2005 to which priority is claimed and which is incorporated herein by reference in its entirety as well as the provisional application to which that application claims priority to (U.S. Provisional Application No. 60/616,754 entitled “Method and System for Controlled Thermal Injury of Human Superficial Tissue”).

[0032] In accordance with various aspects of the present invention, a method and system for noninvasive face lifts and deep tissue tightening are provided. For example, in accordance with an exemplary embodiment, with reference to FIG. 1, an exemplary treatment system 100 configured to treat a region of interest 106 comprises a control system 102, an imaging/therapy probe with acoustic coupling 104, and a display system 108. Control system 102 and display system 108 can comprise various configurations for controlling probe 102 and overall system 100 functionality, such as, for example, a microprocessor with software and a plurality of input/output devices, system and devices for controlling electronic and/or mechanical scanning and/or multiplexing of transducers, a system for power delivery, systems for monitoring, systems for sensing the spatial position of the probe and/or transducers, and/or systems for handling user input and recording treatment results, among others. Imaging/therapy probe 104 can comprise various probe and/or transducer configurations. For example, probe 104 can be configured for a combined dual-mode imaging/therapy transducer, coupled or co-housed imaging/therapy transducers, or simply a separate therapy probe and an imaging probe.

[0033] In accordance with an exemplary embodiment, treatment system 100 is configured for treating the SMAS region by first, imaging of region of interest 106 for localization of the treatment area and surrounding structures, second, delivery of ultrasound energy at a depth, distribution, timing, and energy level to achieve the desired therapeutic effect, and third to monitor the treatment area before, during, and after therapy to plan and assess the results and/or provide feedback. According to another exemplary embodiment of the present invention, treatment system 100 is configured for controlled thermal injury of human superficial tissue based on treatment system 100's ability to controllably create thermal lesions of conformally variable shape, size, and depth through precise spatial and temporal control of acoustic energy deposition.

[0034] As to the treatment of the SMAS region, connective tissue can be permanently tightened by thermal treatment to temperatures about 60 degrees C. or higher. Upon ablating, collagen fibers shrink immediately by approximately 30% of their length. The shrunken fibers can produce tightening of the tissue, wherein the shrinkage should occur along the dominant direction of the collagen fibers. Throughout the body, collagen fibers are laid down in connective tissues along the lines of chronic stress (tension). On the aged face, the collagen fibers of the SMAS region are predominantly oriented along the lines of gravitational tension. Shrinkage of these fibers results in tightening of the SMAS in the direction desired for correction of laxity and sagging due to aging. The treatment comprises the ablation of specific regions of the SMAS region and similar suspensory connective tissues.

[0035] In addition, the SMAS region varies in depth and thickness at different locations, e.g., between 0.5 mm to 5 mm or more. On the face, important structures such as nerves, parotid gland, arteries and veins are present over, under or near the SMAS region. Tightening of the SMAS in certain locations, such as the preauricular region associated with sagging of the cheek to create jowls, the frontal region to associated with sagging brows, mandibular region associated with sagging neck, can be conducted. Treating through localized heating of regions of the SMAS or other suspensory subcutaneous connective tissue structures to temperatures of about 60-90° C., without significant damage to overlying or distal/underlying tissue, i.e., proximal tissue, as well as the precise delivery of therapeutic energy to SMAS regions, and obtaining feedback from the region of interest before, during, and after treatment can be suitably accomplished through treatment system 100.

[0036] To further illustrate an exemplary method and system 200, with reference to FIG. 2, imaging of a region of interest 206, such as by imaging a region 222 and displaying images 224 of the region of interest 206 on a display 208, to facilitate localization of the treatment area and surrounding structures can initially be conducted. Next, delivery of ultrasound energy 220 at a suitably depth, distribution, timing, and energy level to achieve the desired therapeutic effect of thermal injury or ablation to treat SMAS region 216 can be suitably provided by probe 204 through control by control system 202. Monitoring of the treatment area and surrounding structures before, during, and after therapy, i.e., before, during, and after the delivery of ultrasound energy to SMAS region 216, can be provided to plan and assess the results and/or provide feedback to control system 202 and a system user.

[0037] Ultrasound imaging and providing of images 224 can facilitate safe targeting of the SMAS layer 216. For example, with reference to FIG. 2B, specific targeting for the delivery of energy can be better facilitated to avoid heating vital structures such as the facial nerve (motor nerve) 234, parotid gland (which makes saliva) 236, facial artery 238, and trigeminal nerve (for sensory functions) 232 among other regions. Further, use of imaging with targeted energy delivery to provide a limited and controlled depth of treatment can minimize the chance of damaging deep structures, such as for example, the facial nerve that lies below the parotid, which is typically 10 mm thick.

[0038] In accordance with an exemplary embodiment, with reference to FIG. 2C, ultrasound imaging of region 222 of the region of interest 206 can also be used to delineate SMAS layer 216 as the superficial, echo-dense layer overlying facial muscles 218. Such muscles can be seen via imaging region 222 by moving muscles 218, for example by extensional flexing of muscle layer 218 generally towards directions 250 and 252. Such imaging of region 222 may be further enhanced via signal and image processing. Once SMAS layer 216 is localized and/or identified, SMAS layer 216 is ready for treatment.

[0039] The delivery of ultrasound energy 220 at a suitably depth, distribution, timing, and energy level is provided by probe 204 through controlled operation by control system 202 to achieve the desired therapeutic effect of thermal injury to treat SMAS region 216. During operation, probe 204 can also be mechanically and/or electronically scanned within tissue surface region 226 to treat an extended area. In addition, spatial control of a treatment depth 220 can be suitably adjusted in various ranges, such as between a wide range of approximately 0 to 15 mm, suitably fixed to a few discrete depths, with an adjustment limited to a fine range, e.g. approximately between 3 mm to 9 mm, and/or dynamically adjusted during treatment, to treat SMAS layer 216 that typically lies at a depth between approximately 5 mm to 7 mm. Before, during, and after the delivery of ultrasound energy to SMAS region 216, monitoring of the treatment area and surrounding structures can be provided to plan and assess the results and/or provide feedback to control system 202 and a system user.

[0040] For example, in accordance with an exemplary embodiment, with additional reference to FIG. 2D, ultrasound imaging of region 222 can be used to monitor treatment by watching the amount of shrinkage of SMAS layer 216 in direction of areas 260 and 262, such as in real time or quasi-real time, during and after energy delivery to region 220. The onset of substantially immediate shrinkage of SMAS layer 216 is detectable by ultrasound imaging of region 222 and may be further enhanced via image and signal processing. The monitoring of such shrinkage can be ideal because it can confirm the intended therapeutic goal of noninvasive lifting and tissue tightening; in addition, such monitoring may be used for system feedback. In addition to image monitoring, additional treatment parameters that can be suitably monitored in accordance with various other exemplary embodiments may include temperature, video, profilometry, strain imaging and/or gauges or any other suitable spatial, temporal and/or other tissue parameters.

[0041] For example, in accordance with an exemplary embodiment of the present invention, with additional reference to FIG. 2E, an exemplary monitoring method and system 200 may suitably monitor the temperature profile or other tissue parameters of the region of interest 206, such as attenuation or speed of sound of treatment region 222 and suitably adjust the spatial and/or temporal characteristics and energy levels of ultrasound therapy transducer probe 204. The results of such monitoring techniques may be indicated on display 208 in various manners, such as, for example, by way of one-, two-, or three-dimensional images of monitoring results 270, or may comprise an indicator 272, such as a success, fail and/or completed/done type of indication, or combinations thereof.

[0042] In accordance with another exemplary embodiment, with reference to FIG. 2F, the targeting of particular region 220 within SMAS layer 216 can be suitably be expanded within region of interest 206 to include a combination of tissues, such as skin 210, dermis 212, fat/adipose tissue 214, SMAS/muscular fascia/and/or other suspensory tissue 216, and muscle 218. Treatment of a combination of such tissues and/or fascia may be treated including at least one of SMAS layer 216 or other layers of muscular fascia in combination with at least one of muscle tissue, adipose tissue, SMAS and/or other muscular fascia, skin, and dermis, can be suitably achieved by treatment system 200. For example, treatment of SMAS layer 216 may be performed in combination with treatment of dermis 280 by suitable adjustment of the spatial and temporal parameters of probe 204 within treatment system 200.

[0043] In accordance with various aspects of the present invention, a therapeutic treatment method and system for controlled thermal injury of human superficial tissue to effectuate face lifts, deep tissue tightening, and other procedures is based on the ability to controllably create thermal lesions of conformally variable shape, size, and depth through precise spatial and temporal control of acoustic energy deposition. With reference to FIG. 1, in accordance with an exemplary embodiment, an exemplary therapeutic treatment system 200 includes a control system 102 and a probe system 104 that can facilitate treatment planning, controlling and/or delivering of acoustic energy, and/or monitoring of treatment conditions to a region of interest 106. Region-of-interest 106 is configured within the human superficial tissue comprising from just below the tissue outer surface to approximately 30 mm or more in depth.

[0044] Therapeutic treatment system 100 is configured with the ability to controllably produce conformal lesions of thermal injury in superficial human tissue within region of interest 106 through precise spatial and temporal control of acoustic energy deposition, i.e., control of probe 104 is confined within selected time and space parameters, with such control being independent of the tissue. In accordance with an exemplary embodiment, control system 102 and probe system 104 can be suitably configured for spatial control of the acoustic energy by controlling the manner of distribution of the acoustical energy. For example, spatial control may be realized through selection of the type of one or more transducer configurations insonifying region of interest 106, selection of the placement and location of probe system 104 for delivery of acoustical energy relative to region-of-interest 106, e.g., probe system 104 being configured for scanning over part or whole of region-of-interest 106 to produce contiguous thermal injury having a particular orientation or otherwise change in distance from region-of-interest 106, and/or control of other environment parameters, e.g., the temperature at the acoustic coupling interface can be controlled, and/or the coupling of probe 104 to human tissue. In addition to the spatial control parameters, control system 102 and probe system 104 can also be configured for temporal control, such as through adjustment and optimization of drive amplitude levels, frequency/waveform selections, e.g., the types of pulses, bursts or continuous waveforms, and timing sequences and other energy drive characteristics to control thermal ablation of tissue. The spatial and/or temporal control can also be facilitated through open-loop and closed-loop feedback arrangements, such as through the monitoring of various spatial and temporal characteristics. As a result, control of acoustical energy within six degrees of freedom, e.g., spatially within the X, Y and Z domain, as well as the axis of rotation within the XY, YZ and XZ domains, can be suitably achieved to generate conformal lesions of variable shape, size and orientation.

[0045] For example, through such spatial and/or temporal control, an exemplary treatment system 100 can enable the regions of thermal injury to possess arbitrary shape and size and allow the tissue to be destroyed (ablated) in a controlled manner. With reference to FIG. 14, one or more thermal lesions may be created within a tissue region of interest 1400, with such thermal lesions having a narrow or wide lateral extent, long or short axial length, and/or deep or shallow placement, including up to a tissue outer surface 1403. For example, cigar shaped lesions may be produced in a vertical disposition 1404 and/or horizontal disposition 1406. In addition, raindrop-shaped lesions 1408, flat planar lesions 1410, round lesions 1412 and/or other v-shaped/ellipsoidal lesions 1414 may be formed, among others. For example, mushroom-shaped lesion 1420 may be provided, such as through initial generation of a an initial round or cigar-shaped lesion 1422, with continued application of ablative ultrasound resulting in thermal expansion to further generate a growing lesion 1424, such thermal expansion being continued until raindrop-shaped lesion 1420 is achieved. The plurality of shapes can also be configured in various sizes and orientations, e.g., lesions 1408 could be rotationally oriented clockwise or counterclockwise at any desired angle, or made larger or smaller as selected, all depending on spatial and/or temporal control. Moreover, separate islands of destruction, i.e., multiple lesions separated throughout the tissue region, may also be created over part of or the whole portion within tissue region-of-interest 1400. In addition, contiguous structures and/or overlapping structures 1416 may be provided from the controlled configuration of discrete lesions. For example, a series of one or more crossed-lesions 1418 can be generated along a tissue region to facilitate various types of treatment methods.

[0046] The specific configurations of controlled thermal injury are selected to achieve the desired tissue and therapeutic effect(s). For example, any tissue effect can be realized, including but not limited to thermal and non-thermal streaming, cavitational, hydrodynamic, ablative, hemostatic, diathermic, and/or resonance-induced tissue effects. Such effects can be suitably realized at treatment depths over a range of approximately 0-30000 μm within region of interest 200 to provide a high degree of utility.

[0047] An exemplary control system 202 and display system 208 may be configured in various manners for controlling probe and system functionality. With reference again to FIGS. 3A and 3B, in accordance with exemplary embodiments, an exemplary control system 300 can be configured for coordination and control of the entire therapeutic treatment process for noninvasive face lifts and deep tissue tightening. For example, control system 300 can suitably comprise power source components 302, sensing and monitoring components 304, cooling and coupling controls 306, and/or processing and control logic components 308. Control system 300 can be configured and optimized in a variety of ways with more or less subsystems and components to implement the therapeutic system for controlled thermal injury, and the embodiments in FIGS. 3A and 3B are merely for illustration purposes.

[0048] For example, for power sourcing components 302, control system 300 can comprise one or more direct current (DC) power supplies 303 configured to provide electrical energy for entire control system 300, including power required by a transducer electronic amplifier/driver 312. A DC current sense device 305 can also be provided to confirm the level of power going into amplifiers/drivers 312 for safety and monitoring purposes.

[0049] Amplifiers/drivers 312 can comprise multi-channel or single channel power amplifiers and/or drivers. In accordance with an exemplary embodiment for transducer array configurations, amplifiers/drivers 312 can also be configured with a beamformer to facilitate array focusing. An exemplary beamformer can be electrically excited by an oscillator/digitally controlled waveform synthesizer 310 with related switching logic.

[0050] The power sourcing components can also include various filtering configurations 314. For example, switchable harmonic filters and/or matching may be used at the output of amplifier/driver 312 to increase the drive efficiency and effectiveness. Power detection components 316 may also be included to confirm appropriate operation and calibration. For example, electric power and other energy detection components 316 may be used to monitor the amount of power going to an exemplary probe system.

[0051] Various sensing and monitoring components 304 may also be suitably implemented within control system 300. For example, in accordance with an exemplary embodiment, monitoring, sensing and interface control components 324 may be configured to operate with various motion detection systems implemented within transducer probe 204 to receive and process information such as acoustic or other spatial and temporal information from a region of interest. Sensing and monitoring components can also include various controls, interfacing and switches 309 and/or power detectors 316. Such sensing and monitoring components 304 can facilitate open-loop and/or closed-loop feedback systems within treatment system 200.

[0052] Still further, monitoring, sensing and interface control components 324 may comprise imaging systems configured for one-dimensional, two-dimensional and/or three dimensional imaging functions. Such imaging systems can comprise any imaging modality based on at least one of photography and other visual optical methods, magnetic resonance imaging (MRI), computed tomography (CT), optical coherence tomography (OCT), electromagnetic, microwave, or radio frequency (RF) methods, positron emission tomography (PET), infrared, ultrasound, acoustic, or any other suitable method of visualization, localization, or monitoring of a region-of-interest 106. Still further, various other tissue parameter monitoring components, such as temperature measuring devices and components, can be configured within monitoring, sensing and interface control components 324, such monitoring devices comprising any modality now known or hereinafter devised.

[0053] Cooling/coupling control systems 306 may be provided to remove waste heat from an exemplary probe 204, provide a controlled temperature at the superficial tissue interface and deeper into tissue, and/or provide acoustic coupling from transducer probe 204 to region-of-interest 206. Such cooling/coupling control systems 306 can also be configured to operate in both open-loop and/or closed-loop feedback arrangements with various coupling and feedback components.

[0054] Processing and control logic components 308 can comprise various system processors and digital control logic 307, such as one or more of microcontrollers, microprocessors, field-programmable gate arrays (FPGAs), computer boards, and associated components, including firmware and control software 326, which interfaces to user controls and interfacing circuits as well as input/output circuits and systems for communications, displays, interfacing, storage, documentation, and other useful functions. System software and firmware 326 controls all initialization, timing, level setting, monitoring, safety monitoring, and all other system functions required to accomplish user-defined treatment objectives. Further, various control switches 308 can also be suitably configured to control operation.

[0055] An exemplary transducer probe 204 can also be configured in various manners and comprise a number of reusable and/or disposable components and parts in various embodiments to facilitate its operation. For example, transducer probe 204 can be configured within any type of transducer probe housing or arrangement for facilitating the coupling of transducer to a tissue interface, with such housing comprising various shapes, contours and configurations. Transducer probe 204 can comprise any type of matching, such as for example, electric matching, which may be electrically switchable; multiplexer circuits and/or aperture/element selection circuits; and/or probe identification devices, to certify probe handle, electric matching, transducer usage history and calibration, such as one or more serial EEPROM (memories). Transducer probe 204 may also comprise cables and connectors; motion mechanisms, motion sensors and encoders; thermal monitoring sensors; and/or user control and status related switches, and indicators such as LEDs. For example, a motion mechanism in probe 204 may be used to controllably create multiple lesions, or sensing of probe motion itself may be used to controllably create multiple lesions and/or stop creation of lesions, e.g. for safety reasons if probe 204 is suddenly jerked or is dropped. In addition, an external motion encoder arm may be used to hold the probe during use, whereby the spatial position and attitude of probe 104 is sent to the control system to help controllably create lesions. Furthermore, other sensing functionality such as profilometers or other imaging modalities may be integrated into the probe in accordance with various exemplary embodiments. Moreover, the therapy contemplated herein can also be produced, for example, by transducers disclosed in U.S. application Ser. No. 10/944,499, filed on Sep. 16, 2004, entitled METHOD AND SYSTEM FOR ULTRASOUND TREATMENT WITH A MULTI-DIRECTIONAL TRANSDUCER and U.S. application Ser. No. 10/944,500, filed on Sep. 16, 2004, and entitled SYSTEM AND METHOD FOR VARIABLE DEPTH ULTRASOUND TREATMENT, both hereby incorporated by reference.

[0056] With reference to FIGS. 4A and 4B, in accordance with an exemplary embodiment, a transducer probe 400 can comprise a control interface 402, a transducer 404, coupling components 406, and monitoring/sensing components 408, and/or motion mechanism 410. However, transducer probe 400 can be configured and optimized in a variety of ways with more or less parts and components to provide ultrasound energy for controlled thermal injury, and the embodiment in FIGS. 4A and 4B are merely for illustration purposes. Transducer 404 can be any transducer configured to produce conformal lesions of thermal injury in superficial human tissue within a region of interest through precise spatial and temporal control of acoustic energy deposition.

[0057] Control interface 402 is configured for interfacing with control system 300 to facilitate control of transducer probe 400. Control interface components 402 can comprise multiplexer/aperture select 424, switchable electric matching networks 426, serial EEPROMs and/or other processing components and matching and probe usage information 430 and interface connectors 432.

[0058] Coupling components 406 can comprise various devices to facilitate coupling of transducer probe 400 to a region of interest. For example, coupling components 406 can comprise cooling and acoustic coupling system 420 configured for acoustic coupling of ultrasound energy and signals. Acoustic cooling/coupling system 420 with possible connections such as manifolds may be utilized to couple sound into the region-of-interest, control temperature at the interface and deeper into tissue, provide liquid-filled lens focusing, and/or to remove transducer waste heat. Coupling system 420 may facilitate such coupling through use of various coupling mediums, including air and other gases, water and other fluids, gels, solids, and/or any combination thereof, or any other medium that allows for signals to be transmitted between transducer active elements 412 and a region of interest. In addition to providing a coupling function, in accordance with an exemplary embodiment, coupling system 420 can also be configured for providing temperature control during the treatment application. For example, coupling system 420 can be configured for controlled cooling of an interface surface or region between transducer probe 400 and a region of interest and beyond by suitably controlling the temperature of the coupling medium. The suitable temperature for such coupling medium can be achieved in various manners, and utilize various feedback systems, such as thermocouples, thermistors or any other device or system configured for temperature measurement of a coupling medium. Such controlled cooling can be configured to further facilitate spatial and/or thermal energy control of transducer probe 400.

[0059] In accordance with an exemplary embodiment, with additional reference to FIG. 11, acoustic coupling and cooling 1140 can be provided to acoustically couple energy and imaging signals from transducer probe 1104 to and from the region of interest 1106, to provide thermal control at the probe to region-of-interest interface 1110 and deeper into tissue, and to remove potential waste heat from the transducer probe at region 1144. Temperature monitoring can be provided at the coupling interface via a thermal sensor 1146 to provides a mechanism of temperature measurement 1148 and control via control system 1102 and a thermal control system 1142. Thermal control may consist of passive cooling such as via heat sinks or natural conduction and convection or via active cooling such as with peltier thermoelectric coolers, refrigerants, or fluid-based systems comprised of pump, fluid reservoir, bubble detection, flow sensor, flow channels/tubing 1144 and thermal control 1142.

[0060] With continued reference to FIG. 4, monitoring and sensing components 408 can comprise various motion and/or position sensors 416, temperature monitoring sensors 418, user control and feedback switches 414 and other like components for facilitating control by control system 300, e.g., to facilitate spatial and/or temporal control through open-loop and closed-loop feedback arrangements that monitor various spatial and temporal characteristics.

[0061] Motion mechanism 410 can comprise manual operation, mechanical arrangements, or some combination thereof. For example, a motion mechanism 422 can be suitably controlled by control system 300, such as through the use of accelerometers, encoders or other position/orientation devices 416 to determine and enable movement and positions of transducer probe 400. Linear, rotational or variable movement can be facilitated, e.g., those depending on the treatment application and tissue contour surface.

[0062] Transducer 404 can comprise one or more transducers configured for treating of SMAS layers and targeted regions. Transducer 404 can also comprise one or more transduction elements and/or lenses 412. The transduction elements can comprise a piezoelectrically active material, such as lead zirconante titanate (PZT), or any other piezoelectrically active material, such as a piezoelectric ceramic, crystal, plastic, and/or composite materials, as well as lithium niobate, lead titanate, barium titanate, and/or lead metaniobate. In addition to, or instead of, a piezoelectrically active material, transducer 404 can comprise any other materials configured for generating radiation and/or acoustical energy. Transducer 404 can also comprise one or more matching layers configured along with the transduction element such as coupled to the piezoelectrically active material. Acoustic matching layers and/or damping may be employed as necessary to achieve the desired electroacoustic response.

[0063] In accordance with an exemplary embodiment, the thickness of the transduction element of transducer 404 can be configured to be uniform. That is, a transduction element 412 can be configured to have a thickness that is substantially the same throughout. In accordance with another exemplary embodiment, the thickness of a transduction element 412 can also be configured to be variable. For example, transduction element(s) 412 of transducer 404 can be configured to have a first thickness selected to provide a center operating frequency of approximately 2 kHz to 75 MHz, such as for imaging applications. Transduction element 412 can also be configured with a second thickness selected to provide a center operating frequency of approximately 2 to 400 MHz, and typically between 4 MHz and 15 MHz for therapy application. Transducer 404 can be configured as a single broadband transducer excited with at least two or more frequencies to provide an adequate output for generating a desired response. Transducer 404 can also be configured as two or more individual transducers, wherein each transducer comprises one or more transduction element. The thickness of the transduction elements can be configured to provide center-operating frequencies in a desired treatment range. For example, transducer 404 can comprise a first transducer configured with a first transduction element having a thickness corresponding to a center frequency range of approximately 1 kHz to 3 MHz, and a second transducer configured with a second transduction element having a thickness corresponding to a center frequency of approximately 3 MHz to 100 MHz or more.

[0064] Transducer 404 may be composed of one or more individual transducers in any combination of focused, planar, or unfocused single-element, multi-element, or array transducers, including 1-D, 2-D, and annular arrays; linear, curvilinear, sector, or spherical arrays; spherically, cylindrically, and/or electronically focused, defocused, and/or lensed sources. For example, with reference to an exemplary embodiment depicted in FIG. 5, transducer 500 can be configured as an acoustic array to facilitate phase focusing. That is, transducer 500 can be configured as an array of electronic apertures that may be operated by a variety of phases via variable electronic time delays. By the term “operated,” the electronic apertures of transducer 500 may be manipulated, driven, used, and/or configured to produce and/or deliver an energy beam corresponding to the phase variation caused by the electronic time delay. For example, these phase variations can be used to deliver defocused beams, planar beams, and/or focused beams, each of which may be used in combination to achieve different physiological effects in a region of interest 510. Transducer 500 may additionally comprise any software and/or other hardware for generating, producing and or driving a phased aperture array with one or more electronic time delays.

[0065] Transducer 500 can also be configured to provide focused treatment to one or more regions of interest using various frequencies. In order to provide focused treatment, transducer 500 can be configured with one or more variable depth devices to facilitate treatment. For example, transducer 500 may be configured with variable depth devices disclosed in U.S. patent application Ser. No. 10/944,500, entitled “System and Method for Variable Depth Ultrasound”, filed on Sep. 16, 2004, having at least one common inventor and a common Assignee as the present application, and incorporated herein by reference. In addition, transducer 500 can also be configured to treat one or more additional ROI 510 through the enabling of sub-harmonics or pulse-echo imaging, as disclosed in U.S. patent application Ser. No. 10/944,499, entitled “Method and System for Ultrasound Treatment with a Multi-directional Transducer”, filed on Sep. 16, 2004, having at least one common inventor and a common Assignee as the present application, and also incorporated herein by reference.

[0066] Moreover, any variety of mechanical lenses or variable focus lenses, e.g. liquid-filled lenses, may also be used to focus and or defocus the sound field. For example, with reference to exemplary embodiments depicted in FIGS. 6A and 6B, transducer 600 may also be configured with an electronic focusing array 604 in combination with one or more transduction elements 606 to facilitate increased flexibility in treating ROI 610. Array 604 may be configured in a manner similar to transducer 502. That is, array 604 can be configured as an array of electronic apertures that may be operated by a variety of phases via variable electronic time delays, for example, T₁, T₂ . . . T_j. By the term “operated,” the electronic apertures of array 604 may be manipulated, driven, used, and/or configured to produce and/or deliver energy in a manner corresponding to the phase variation caused by the electronic time delay. For example, these phase variations can be used to deliver defocused beams, planar beams, and/or focused beams, each of which may be used in combination to achieve different physiological effects in ROI 610.

[0067] Transduction elements 606 may be configured to be concave, convex, and/or planar. For example, in an exemplary embodiment depicted in FIG. 6A, transduction elements 606A are configured to be concave in order to provide focused energy for treatment of ROI 610. Additional embodiments are disclosed in U.S. patent application Ser. No. 10/944,500, entitled “Variable Depth Transducer System and Method”, and again incorporated herein by reference.

[0068] In another exemplary embodiment, depicted in FIG. 6B, transduction elements 606B can be configured to be substantially flat in order to provide substantially uniform energy to ROI 610. While FIGS. 6A and 6B depict exemplary embodiments with transduction elements 604 configured as concave and substantially flat, respectively, transduction elements 604 can be configured to be concave, convex, and/or substantially flat. In addition, transduction elements 604 can be configured to be any combination of concave, convex, and/or substantially flat structures. For example, a first transduction element can be configured to be concave, while a second transduction element can be configured to be substantially flat.

[0069] With reference to FIGS. 8A and 8B, transducer 404 can be configured as single-element arrays, wherein a single-element 802, e.g., a transduction element of various structures and materials, can be configured with a plurality of masks 804, such masks comprising ceramic, metal or any other material or structure for masking or altering energy distribution from element 802, creating an array of energy distributions 808. Masks 804 can be coupled directly to element 802 or separated by a standoff 806, such as any suitably solid or liquid material.

[0070] An exemplary transducer 404 can also be configured as an annular array to provide planar, focused and/or defocused acoustical energy. For example, with reference to FIGS. 10A and 10B, in accordance with an exemplary embodiment, an annular array 1000 can comprise a plurality of rings 1012, 1014, 1016 to N. Rings 1012, 1014, 1016 to N can be mechanically and electrically isolated into a set of individual elements, and can create planar, focused, or defocused waves. For example, such waves can be centered on-axis, such as by methods of adjusting corresponding transmit and/or receive delays, τ₁, τ₂, τ₃ . . . τ_N. An electronic focus can be suitably moved along various depth positions, and can enable variable strength or beam tightness, while an electronic defocus can have varying amounts of defocusing. In accordance with an exemplary embodiment, a lens and/or convex or concave shaped annular array 1000 can also be provided to aid focusing or defocusing such that any time differential delays can be reduced. Movement of annular array 800 in one, two or three-dimensions, or along any path, such as through use of probes and/or any conventional robotic arm mechanisms, may be implemented to scan and/or treat a volume or any corresponding space within a region of interest.

[0071] Transducer 404 can also be configured in other annular or non-array configurations for imaging/therapy functions. For example, with reference to FIGS. 10C-10F, a transducer can comprise an imaging element 1012 configured with therapy element(s) 1014. Elements 1012 and 1014 can comprise a single-transduction element, e.g., a combined imaging/transducer element, or separate elements, can be electrically isolated 1022 within the same transduction element or between separate imaging and therapy elements, and/or can comprise standoff 1024 or other matching layers, or any combination thereof. For example, with particular reference to FIG. 10F, a transducer can comprise an imaging element 1012 having a surface 1028 configured for focusing, defocusing or planar energy distribution, with therapy elements 1014 including a stepped-configuration lens configured for focusing, defocusing, or planar energy distribution.

[0072] With a better understanding of the various transducer structures, and with reference again to FIG. 14, how the geometric configuration of the transducer or transducers that contributes to the wide range of lesioning effects can be better understood. For example, cigar-shaped lesions 1404 and 1406 may be produced from a spherically focused source, and/or planar lesions 1410 from a flat source. Concave planar sources and arrays can produce a “V-shaped” or ellipsoidal lesion 1414. Electronic arrays, such as a linear array, can produce defocused, planar, or focused acoustic beams that may be employed to form a wide variety of additional lesion shapes at various depths. An array may be employed alone or in conjunction with one or more planar or focused transducers. Such transducers and arrays in combination produce a very wide range of acoustic fields and their associated benefits. A fixed focus and/or variable focus lens or lenses may be used to further increase treatment flexibility. A convex-shaped lens, with acoustic velocity less than that of superficial tissue, may be utilized, such as a liquid-filled lens, gel-filled or solid gel lens, rubber or composite lens, with adequate power handling capacity; or a concave-shaped, low profile, lens may be utilized and composed of any material or composite with velocity greater than that of tissue. While the structure of transducer source and configuration can facilitate a particular shaped lesion as suggested above, such structures are not limited to those particular shapes as the other spatial parameters, as well as the temporal parameters, can facilitate additional shapes within any transducer structure and source.

[0073] In accordance with various exemplary embodiments of the present invention, transducer 404 may be configured to provide one, two and/or three-dimensional treatment applications for focusing acoustic energy to one or more regions of interest. For example, as discussed above, transducer 404 can be suitably diced to form a one-dimensional array, e.g., transducer 602 comprising a single array of sub-transduction elements.

[0074] In accordance with another exemplary embodiment, transducer 404 may be suitably diced in two-dimensions to form a two-dimensional array. For example, with reference to FIG. 9, an exemplary two-dimensional array 900 can be suitably diced into a plurality of two-dimensional portions 902. Two-dimensional portions 902 can be suitably configured to focus on the treatment region at a certain depth, and thus provide respective slices 904 of the treatment region. As a result, the two-dimensional array 900 can provide a two-dimensional slicing of the image place of a treatment region, thus providing two-dimensional treatment.

[0075] In accordance with another exemplary embodiment, transducer 404 may be suitably configured to provide three-dimensional treatment. For example, to provide-three dimensional treatment of a region of interest, with reference again to FIG. 1, a three-dimensional system can comprise a transducer within probe 104 configured with an adaptive algorithm, such as, for example, one utilizing three-dimensional graphic software, contained in a control system, such as control system 102. The adaptive algorithm is suitably configured to receive two-dimensional imaging, temperature and/or treatment or other tissue parameter information relating to the region of interest, process the received information, and then provide corresponding three-dimensional imaging, temperature and/or treatment information.

[0076] In accordance with an exemplary embodiment, with reference again to FIG. 9, an exemplary three-dimensional system can comprise a two-dimensional array 900 configured with an adaptive algorithm to suitably receive 904 slices from different image planes of the treatment region, process the received information, and then provide volumetric information 906, e.g., three-dimensional imaging, temperature and/or treatment information. Moreover, after processing the received information with the adaptive algorithm, the two-dimensional array 900 may suitably provide therapeutic heating to the volumetric region 906 as desired.

[0077] In accordance with other exemplary embodiments, rather than utilizing an adaptive algorithm, such as three-dimensional software, to provide three-dimensional imaging and/or temperature information, an exemplary three-dimensional system can comprise a single transducer 404 configured within a probe arrangement to operate from various rotational and/or translational positions relative to a target region.

[0078] To further illustrate the various structures for transducer 404, with reference to FIG. 7, ultrasound therapy transducer 700 can be configured for a single focus, an array of foci, a locus of foci, a line focus, and/or diffraction patterns. Transducer 700 can also comprise single elements, multiple elements, annular arrays, one-, two-, or three-dimensional arrays, broadband transducers, and/or combinations thereof, with or without lenses, acoustic components, and mechanical and/or electronic focusing. Transducers configured as spherically focused single elements 702, annular arrays 704, annular arrays with damped regions 706, line focused single elements 708, 1-D linear arrays 710, 1-D curvilinear arrays in concave or convex form, with or without elevation focusing, 2-D arrays, and 3-D spatial arrangements of transducers may be used to perform therapy and/or imaging and acoustic monitoring functions. For any transducer configuration, focusing and/or defocusing may be in one plane or two planes via mechanical focus 720, convex lens 722, concave lens 724, compound or multiple lenses 726, planar form 728, or stepped form, such as illustrated in FIG. 10F. Any transducer or combination of transducers may be utilized for treatment. For example, an annular transducer may be used with an outer portion dedicated to therapy and the inner disk dedicated to broadband imaging wherein such imaging transducer and therapy transducer have different acoustic lenses and design, such as illustrated in FIG. 10C-10F.

[0079] Moreover, such transduction elements 700 may comprise a piezoelectrically active material, such as lead zirconante titanate (PZT), or any other piezoelectrically active material, such as a piezoelectric ceramic, crystal, plastic, and/or composite materials, as well as lithium niobate, lead titanate, barium titanate, and/or lead metaniobate. Transduction elements 700 may also comprise one or more matching layers configured along with the piezoelectrically active material. In addition to or instead of piezoelectrically active material, transduction elements 700 can comprise any other materials configured for generating radiation and/or acoustical energy. A means of transferring energy to and from the transducer to the region of interest is provided.

[0080] In accordance with another exemplary embodiment, with reference to FIG. 12, an exemplary treatment system 200 can be configured with and/or combined with various auxiliary systems to provide additional functions. For example, an exemplary treatment system 1200 for treating a region of interest 1206 can comprise a control system 1202, a probe 1204, and a display 1208. Treatment system 1200 further comprises an auxiliary imaging modality 1274 and/or auxiliary monitoring modality 1272 may be based upon at least one of photography and other visual optical methods, magnetic resonance imaging (MRI), computed tomography (CT), optical coherence tomography (OCT), electromagnetic, microwave, or radio frequency (RF) methods, positron emission tomography (PET), infrared, ultrasound, acoustic, or any other suitable method of visualization, localization, or monitoring of SMAS layers within region-of-interest 1206, including imaging/monitoring enhancements. Such imaging/monitoring enhancement for ultrasound imaging via probe 1204 and control system 1202 could comprise M-mode, persistence, filtering, color, Doppler, and harmonic imaging among others; furthermore an ultrasound treatment system 1270, as a primary source of treatment, may be combined with a secondary source of treatment 1276, including radio frequency (RF), intense pulsed light (IPL), laser, infrared laser, microwave, or any other suitable energy source.

[0081] In accordance with another exemplary embodiment, with reference to FIG. 13, treatment composed of imaging, monitoring, and/or therapy to a region of interest may be further aided, augmented, and/or delivered with passive or active devices 1304 within the oral cavity. For example, if passive or active device 1304 is a second transducer or acoustic reflector acoustically coupled to the cheek lining it is possible to obtain through transmission, tomographic, or round-trip acoustic waves which are useful for treatment monitoring, such as in measuring acoustic speed of sound and attenuation, which are temperature dependent; furthermore such a transducer could be used to treat and/or image. In addition an active, passive, or active/passive object 1304 may be used to flatten the skin, and/or may be used as an imaging grid, marker, or beacon, to aid determination of position. A passive or active device 1304 may also be used to aid cooling or temperature control. Natural air in the oral cavity may also be used as passive device 1304 whereby it may be utilized to as an acoustic reflector to aid thickness measurement and monitoring function.

[0082] During operation of an exemplary treatment system, a lesion configuration of a selected size, shape, orientation is determined. Based on that lesion configuration, one or more spatial parameters are selected, along with suitable temporal parameters, the combination of which yields the desired conformal lesion. Operation of the transducer can then be initiated to provide the conformal lesion or lesions. Open and/or closed-loop feedback systems can also be implemented to monitor the spatial and/or temporal characteristics, and/or other tissue parameter monitoring, to further control the conformal lesions.

[0083] With reference to FIG. 13, a collection of simulation results, illustrating thermal lesion growth over time are illustrated. Such lesion growth was generated with a spherically focused, cylindrically focused, and planar (unfocused) source at a nominal source acoustic power level, W₀ and twice that level, 2 W₀, but any configurations of transducer can be utilized as disclosed herein. The thermal contours indicate where the tissue reached 65° C. for different times. The contour for the cylindrically focused source is along the short axis, or so-called elevation plane. The figure highlights the different shapes of lesions possible with different power levels and source geometries. In addition, with reference to FIG. 14, a pair of lesioning and simulation results is illustrated, showing chemically stained porcine tissue photomicrographs adjacent to their simulation results. In addition, with reference to FIG. 15, another pair of lesioning results is illustrated, showing chemically stained porcine tissue photomicrographs, highlighting a tadpole shaped lesion and a wedge shaped lesion.

[0084] In summary, adjustment of the acoustic field spatial distribution via transducer type and distribution, such as size, element configuration, electronic or mechanical lenses, acoustic coupling and/or cooling, combined with adjustment of the temporal acoustic field, such as through control of transmit power level and timing, transmit frequency and/or drive waveform can facilitate the achieving of controlled thermal lesions of variable size, shape, and depths. Moreover, the restorative biological responses of the human body can further cause the desired effects to the superficial human tissue.

[0085] The present invention has been described above with reference to various exemplary embodiments. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope of the present invention. For example, the various operational steps, as well as the components for carrying out the operational steps, may be implemented in alternate ways depending upon the particular application or in consideration of any number of cost functions associated with the operation of the system, e.g., various of the steps may be deleted, modified, or combined with other steps. These and other changes or modifications are intended to be included within the scope of the present invention, as set forth in the following claims.