Systems and methods for enhancing efficacy of ultrasonic treatment

Abstract

To enhance efficacy of ultrasonic treatment by a highly efficient signal measurement, calibration and assurance system with a control system radio-frequency (RE) driver configured to drive one or more focused ultrasonic transducers.SOLUTION: An RE driver can comprise one or more power amplifiers including one or more III-V semiconductors, (e.g., gallium nitride GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and / or AlGaN) field-effect transistors to efficiently provide high power with distinct narrow-band RE signals over a wide frequency range. The RE driver can include a power measurement and / or calibration system to monitor the amplitude and phase of the RE signal output from the power amplifier and estimate the amount of RE power to be delivered to the ultrasonic transducers.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] Incorporation by Reference U.S. Provisional Patent Application No. 62 / 773,948, filed on Nov. 30, 2019, is incorporated herein by reference in its entirety for all purposes.

Background Art

[0002] Some embodiments described herein relate to high-power, complex voltage, current, and power measurement for ultrasonic transducers, and high-efficiency radio frequency (RF) designs, calibrations, and assemblies and electrical interconnections for ensuring the same. Various embodiments described in this application are directed to electrical devices and systems configured to generate, monitor, and deliver RF signals that power ultrasonic energy-based non-invasive treatments. Some embodiments relate to energy-based non-invasive treatments, for example, to enhance the efficacy of ultrasonic treatments in dermatology (e.g., cosmetic plastic surgery).

[0003] Description of Related Art Ultrasound has been used in the past in both diagnostic and therapeutic fields. Ultrasonic imaging and treatment have been described in various medical fields, including dermatology. Cosmetic plastic surgery procedures using ultrasound have also been described.

Summary of the Invention

[0004] Some embodiments described herein provide systems and methods that overcome certain drawbacks in using ultrasound for therapeutic purposes, including, for example, excessive variance, error generation, and reduced treatment efficiency and effectiveness. In some embodiments, several enhancements are described to reduce signal harmonics that can interfere with signal control and enter the ultrasonic transducer. Such reduction (e.g., via monitoring and calibration techniques) can ultimately reduce undesired variations when using different ultrasonic frequencies, outputs, and / or depths, and thus enhance the overall efficacy and effectiveness of ultrasonic treatment.

[0005] In some embodiments, a high-efficiency control system is provided for directing power, voltage, current, and RF signals to one or more transducers included within the ultrasonic treatment system described in this application. This RF module can include electronic devices, subsystems, and / or assemblies integrated on one or more printed circuit board assemblies.

[0006] In some embodiments, the ultrasonic therapy board includes an output guarantee system for high-intensity focused ultrasound (HIFU) monitoring, and includes a power guarantee measurement and calibration system for performing accurate and phase-sensitive measurement of the electrical drive power to the high-intensity focused ultrasound transducer. In some embodiments, the ultrasonic therapy board incorporates a HIFU switch-mode power amplifier that incorporates one or more high-efficiency transistors such as III-V semiconductors (e.g., III-V compound semiconductors that combine group III elements (e.g., Ga, In, Al) with group V elements (e.g., N, As, Sb, P)), such as gallium nitride (GaN), gallium arsenide (GaAs), gallium antimonide (GaSb), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), indium gallium arsenide (InGaAs), aluminum antimonide (AlSb), aluminum gallium arsenide (AlGaAs), aluminum gallium nitride (AlGaN), etc. (field-effect transistors), and a radio frequency (RF) therapy power amplifier that uses either a field-effect transistor such as GaN (III-V) or a power transformer (e.g., a Guanella type transformer or other type of transformer) delivers high-output RF energy to the high-intensity focused ultrasound transducer. In some embodiments, GaN transistors are described, but in other contemplated embodiments, any one, two, three, or more of the transistors of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and / or AlGaN may be used. In various embodiments, one or more III-V semiconductors are not used, e.g., excluded. In some embodiments, any one or more of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and / or AlGaN are not used.In some embodiments, the ultrasonic treatment board includes a system and method for predicting the output power to any HIFU transducer load, and the system for using calibration information stores, using a power amplifier and the transducer, to predict the output power that will be delivered to the transducer by the amplifier prior to the performance of the treatment. In some embodiments, the ultrasonic treatment system includes a resistive current sensing and voltage sensing component, a demodulator that can operate at any frequency, a phase shift harmonic cancellation scheme, and / or a self-calibrating two-terminal pair compensation scheme.

[0007] In some embodiments, systems and methods are provided that use ultrasonic treatment with a targeted high-precision ultrasound to successfully improve the safety, effectiveness, and / or efficiency of aesthetic effects and perform various treatment and / or image processing procedures, resulting in visible and effective skin shaping (e.g., cosmetic shaping) results via a thermal pathway. Various embodiments of the ultrasonic treatment board can include various health monitoring systems configured to ensure the safety of the patient during surgery. Further, systems and methods are also envisioned in the present application that can suppress and / or reduce the harmonics of the electrical signals output from the ultrasonic treatment board to ensure the safety of the patient.

[0008] In various embodiments, the present invention provides one or more advantages, which include, for example, reducing treatment time and / or error, creating a unique heating pattern, multiple channels of higher power, options for treating areas at two or more depths using the same or different output levels (e.g., coagulation, ablation, instantaneous necrosis focus zone, and another defocusing energy, or other combinations), optional simultaneous or sequential treatment at different depths (such as depths of 1.5 mm, 3 mm, and / or 4.5 mm below the skin surface where coagulation is directed simultaneously, or in overlapping or consecutive periods), and / or utilizing treatment at one, two, or more simultaneous points, linear or line foci, at different depths such as beneath an area or separated different depths. Some embodiments described herein are particularly advantageous because they include one, some, or all of the following benefits, regardless of whether they are in the field of dermatology or non-dermatology, and those benefits are narrow bandwidth frequency ultrasonic treatment at multiple depths using a more efficient treatment, (i) a faster treatment time, (ii) reduction of pain during treatment, (iii) reduction of pain after treatment, (iv) shortening of recovery time, (v) a more efficient treatment, (vi) improvement of customer satisfaction, (vii) reduction of energy until treatment completion, and / or (viii) a wider treatment area by the focus area, including one or more of them. In some embodiments, those advantages include modulation of the effective amplitude for driving a transducer using a signal for driving a field effect transistor generated by comparing the output sine wave of a direct digital synthesis circuit with a DC voltage.

[0009] In some embodiments, the electronic device, subsystem, and / or assembly of the RF module can be configured to generate an RF output of about 0.1 W to 200 W (e.g., about 20 - 100 W) with high efficiency over a frequency range of 1 MHz to 20 MHz (e.g., about 1 MHz, 1.75 MHz, 1.75 - 12 MHz, 4 - 12 MHz, 4 MHz, 7 MHz, 10 MHz, 12 MHz) and deliver it to one or more ultrasonic transducers. In particular, the RF module can include a power amplifier that includes III-V (e.g., gallium nitride (GaN), GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and / or AlGaN) field effect transistors (FETs) and generates one or more narrowband RF signals at a frequency of 1.0 MHz to 12.0 MHz with high efficiency (e.g., 75%, 50% - 90%, 95%, 99%, or any value among them). Further, the RF module can include a power measurement system configured to monitor the amplitude and phase of one or more RF signals generated by III-V (e.g., GaN and others) FETs. Further, the system and method evaluate the amount of power that would be delivered by one or more ultrasonic transducers when paired with a drive system that includes a power amplifier including III-V (e.g., GaN and others) FETs. In some embodiments, GaN transistors are described, but in other contemplated embodiments, any of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and / or AlGaN transistors may be used.

[0010] In various embodiments, an ultrasonic treatment system includes an ultrasonic probe including an ultrasonic treatment transducer adapted to apply ultrasonic treatment to tissue, and a power system configured to provide power to the ultrasonic treatment transducer, the power system including a power amplifier device and circuitry, the power amplifier device including at least one semiconductor transistor, the semiconductor transistor being a field effect transistor, the field effect transistor being configured to operate at an efficiency of at least 75% at a radio frequency (RF) in the range of 200 kHz to 20 MHz. In one embodiment, the semiconductor transistor includes a Group III-V compound. In one embodiment, the semiconductor transistor includes gallium nitride (GaN).

[0011] In one embodiment, the power amplifier device includes a switch-mode amplifier design including at least semiconductors, and a circuit configured to generate a digital waveform for driving the semiconductors so as to drive an ultrasonic therapy transducer. In one embodiment, the power amplifier device is a switch-mode amplifier design including at least one semiconductor, and in one embodiment, each semiconductor includes a plurality of gates (in another embodiment, each gallium nitride field-effect transistor does not include a plurality of gates), the switch-mode amplifier design, and a circuit configured to generate a digital waveform for driving the semiconductors so as to drive an ultrasonic therapy transducer. In one embodiment, the power amplifier device is a switch-mode amplifier design including at least one gallium nitride field-effect transistor, and in one embodiment, each gallium nitride field-effect transistor includes a plurality of gates (in another embodiment, each gallium nitride field-effect transistor does not include a plurality of gates), the switch-mode amplifier design, and in one embodiment, a circuit configured to generate a digital waveform for driving a plurality of gates of the gallium nitride field-effect transistor so as to drive a piezoelectric ultrasonic therapy transducer as the ultrasonic therapy transducer. In one embodiment, the signal for driving the field-effect transistor is generated by comparing the output of a sine wave direct digital synthesis circuit with a DC voltage. In one embodiment, the system includes a signal for driving a field-effect transistor, which is generated by comparing the output sine wave of a direct digital synthesis circuit with a DC voltage and is configured for modulation of the effective amplitude for driving the transducer. In one embodiment, the output power is in the range of 5W to 50W, or 30W to 100W. In one embodiment, the circuit includes four transistors configured in an H-bridge configuration. In one embodiment, the circuit includes four gallium nitride transistors configured in an H-bridge configuration. In one embodiment, the circuit includes two transistors configured in a half-bridge configuration. In one embodiment, the circuit includes two gallium nitride transistors configured in a half-bridge configuration.In one embodiment, the gate drive signal has a variable duty cycle that is used to control the harmonic content and power of the output signal. In one embodiment, the power amplifier converter supplies power to the radio frequency output signal output with an efficiency exceeding 75%. In one embodiment, the supply voltage to the power amplifier is modulated using a switched-mode DC-DC converter that reduces a fixed high voltage input to a low supply voltage. In one embodiment, the system includes two or more power amplifiers, and a single power amplifier is configured to drive a single piezoelectric conversion element of a high-intensity focused ultrasound transducer. In one embodiment, the high-intensity focused ultrasound transducer is configured to be driven by a separate power amplifier. In one embodiment, the high-intensity focused ultrasound transducer includes a plurality of piezoelectric conversion elements, and each of the plurality of piezoelectric conversion elements is configured to be driven by a separate power amplifier. In one embodiment, the power amplifier is configured to drive the output at two or more different amplitudes. In one embodiment, the power amplifier is configured to drive the output at two or more different phases. In one embodiment, the amplifier is configured to drive the output at two or more different frequencies. In one embodiment, the phase and frequency are controlled by a direct digital synthesizer. In one embodiment, the system is configured to drive the transducer in the impedance range of 20 ohms to 120 ohms and the phase angle range of +45 degrees to -45 degrees.

[0012] In one embodiment, the power amplifier device includes a switched-mode amplifier design including at least one field effect transistor and a circuit configured to generate a digital waveform for driving a plurality of gates of the field effect transistors to drive a piezoelectric ultrasonic transducer, the circuit including four transistors configured in an H-bridge configuration.

[0013] In one embodiment, the power amplifier device includes a switched-mode amplifier design including at least one field-effect transistor, and a circuit configured to generate a digital waveform for driving a plurality of gates of the field-effect transistor so as to drive a piezoelectric ultrasonic transducer. The signal for driving the field-effect transistor is generated by comparing the output of a sine-wave direct digital synthesis circuit with a DC voltage. The output power ranges from 30 W to 100 W, and the circuit includes four transistors configured in an H-bridge configuration.

[0014] In one embodiment, the semiconductor is gallium nitride, and the power amplifier device is a switched-mode amplifier design including at least one gallium nitride field-effect transistor, each gallium nitride field-effect transistor including a plurality of gates, and a circuit configured to generate a digital waveform for driving a plurality of gates of the gallium nitride field-effect transistor so as to drive a piezoelectric ultrasonic transducer. The signal for driving the field-effect transistor is generated by comparing the output of a sine-wave direct digital synthesis circuit with a DC voltage. The output power is in the range of 30 W to 100 W, and the circuit includes four gallium nitride transistors configured in an H-bridge configuration. The gate drive signal has a variable duty cycle used to control the harmonic content and output of the output signal. The power amplifier converter supplies power to the radio frequency output signal output with an efficiency exceeding 75%. The supply voltage to the power amplifier is modulated using a switched-mode DC-DC converter that reduces a fixed high voltage input to a low supply voltage. It includes two or more power amplifiers. A single power amplifier is configured to drive a single piezoelectric conversion element of a high-intensity focused ultrasonic transducer. The power amplifier is configured to drive the output at two or more different amplitudes. The power amplifier is configured to drive the output at two or more different phases. The phase and frequency are controlled by a direct digital synthesizer. The system is configured to drive the transducer with an impedance in the range of 20 ohms to 120 ohms and a phase angle of +45 degrees to -45 degrees.

[0015] In various embodiments, a power amplifier device for driving a high-intensity ultrasonic transducer includes a switched-mode amplifier design that includes at least one field-effect transistor, and a circuit configured to generate a digital waveform for driving at least one field-effect transistor. In various embodiments, a power amplifier device for driving a high-intensity ultrasonic transducer includes a switched-mode amplifier design that includes at least one gallium nitride field-effect transistor, and a circuit configured to generate a digital waveform for driving at least one gallium nitride field-effect transistor.

[0016] In various embodiments, a power amplifier device for driving a high-intensity ultrasonic transducer is a switched-mode amplifier design that includes at least one gallium nitride field-effect transistor, where each gallium nitride field-effect transistor includes a plurality of gates, and a circuit configured to generate a digital waveform for driving the plurality of gates of the gallium nitride field-effect transistors to drive a piezoelectric ultrasonic transducer. In one embodiment, a power amplifier device for driving a high-intensity ultrasonic transducer includes a switched-mode amplifier design that includes a plurality of gallium nitride field-effect transistors, and a circuit configured to generate a digital waveform for driving the plurality of gallium nitride field-effect transistors to drive a piezoelectric ultrasonic transducer.

[0017] In various embodiments, the power amplifier device includes one or more of the following features, namely, the power amplifier is configured to drive the output at two or more different amplitudes, and the power amplifier is configured to drive the output at two or more different phases. In one embodiment, the power amplifier is configured to drive the output at two or more different frequencies.

[0018] In various embodiments, a method for controlling the power of an ultrasonic system to deliver a desired amount of focused acoustic output by an ultrasonic transducer includes providing a power control system that includes a control system microprocessor and a circuit including a control system look-up table (LUT), providing an ultrasonic transducer that includes a transducer controller, a transducer microprocessor, and a transducer LUT, using the transducer microprocessor to determine from the transducer LUT the amount of power delivered to a load that is equivalent to the desired amount of acoustic output delivered to tissue by the ultrasonic transducer, using the control system microprocessor to determine from the control system LUT the amplitude of an electrical signal output from a power amplifier of the power system that would deliver an equivalent amount of power to the load, and setting the determined amplitude of the electrical signal output to at least one parameter of the power system output. In various embodiments, the load is in the range of 10 to 100 ohms, or 20 to 120 ohms (e.g., 10 to 40, 40 to 80, 80 to 120, and overlapping ranges therein), which allows for a wide range of transducer impedance that can occur during phase adjustment / focusing of the transducer. In one embodiment, the load is 50 ohms.

[0019] In various embodiments, an ultrasonic treatment system includes an ultrasonic probe that houses a piezoelectrically-driven ultrasonic therapy transducer adapted to focus acoustic ultrasonic waves to a depth from the housing within a focal zone in tissue, and a power system configured to supply power to the ultrasonic therapy transducer, the power system including a power amplifier, and a power measurement system configured to monitor an electrical output from an output signal of the power amplifier, the power measurement system including a resistive current sensing circuit configured to monitor a current output from the power amplifier and a resistive voltage sensing circuit configured to monitor a voltage output from the power amplifier, and the power measurement system being configured to monitor the electrical output power from the power amplifier over a frequency range of at least 2 octaves for the ultrasonic therapy transducer.

[0020] In various embodiments, a system for measuring radio frequency (RF) current and voltage in a drive circuit within a high intensity focused ultrasound system includes a current sensing resistor in series with a load, a shunt voltage sensing resistor network in parallel with the load, and a power output voltage and current monitoring circuit (IQ demodulation circuit) having a local oscillator clock synchronized in phase and frequency to a signal driving the power amplifier and configured to demodulate an output signal to a carrier frequency lower than the ultrasonic drive frequency.

[0021] In one embodiment, the measurement system is configured to obtain a plurality of measurements with different relative phase shifts between the local oscillator and the power amplifier. In one embodiment, the local oscillator clock is generated from a direct digital synthesizer that is independently controlled. In one embodiment, the measurement system is configured to obtain a plurality of measurements at the local oscillator frequency. In one embodiment, the number of phase measurements is six. In one embodiment, the system uses the measurement system to modify a gate drive signal to achieve a desired harmonic content in the output signal.

[0022] In various embodiments, a method for determining some measurement values appropriately measures harmonics by evaluating some harmonics of the lowest frequency within the passband that exceed the system noise floor. In one embodiment, the method calculates the complex harmonic components of the voltage and current waveforms by forming a linear combination of a plurality of measurement values.

[0023] In various embodiments, a method for calibrating a high-intensity ultrasonic transducer includes calibrating the acoustic output power delivered by the transducer of the driver configuration corresponding to the power delivered by the driver against one or more reference loads of the driver configuration where calibration information is stored using the transducer, calibrating the electrical driver configuration against the power delivered to one or more reference loads where calibration information is stored using the driver, using the transducer calibration information to determine the power level to one or more reference loads for a desired acoustic output setting, and using the driver calibration information to determine the driver configuration for a desired acoustic output power level to the reference load, and calculating using a processor of the driver configuration to achieve the desired acoustic output power.

[0024] In one embodiment, the transducer calibration information also includes the power delivered to the transducer at each acoustic output level, and the stored power information includes complex power components or real power components. In one embodiment, a dynamic measurement of the power delivered from the driver is performed during ultrasonic irradiation of the tissue and verified against the power accumulated in the transducer calibration for the desired acoustic output level.

[0025] In various embodiments, the method tunes a high-intensity focused ultrasonic transducer by sweeping the frequency while measuring the voltage standing wave ratio in the driver and selecting the frequency that minimizes the voltage standing wave ratio as the operating frequency.

[0026] In one embodiment, the acoustic output power is generated by performing measurements using force balance. In one embodiment, the transducer calibration is stored as a reference table in a non-volatile memory chip within the transducer. In one embodiment, at least one of the voltage or current measured at the driver is adjusted using a transmission matrix represented by a two-port network between the treatment drive circuit output and the transducer. In one embodiment, the calibration information is stored in a look-up table (LUT). In one embodiment, the target voltage is calculated from the calibration information and a desired acoustic output set at the clinic by interpolating values within one or more reference tables. In one embodiment, the storage device within the transducer calibration information for the power threshold at each acoustic output level defines an acceptable range of electrical drive power so as to achieve an acceptable range of acoustic output power.

[0027] In various embodiments, the system includes confirming that the dynamically measured power is within a specified range that includes dynamically measuring the power delivered by the driver and comparing the power to a threshold stored within the transducer. In one embodiment, the transmission matrix of the handpiece and cable assembly that can be exchanged between the transducer and the driver is stored on a non-volatile memory chip within the handpiece and cable assembly.

[0028] In various embodiments, the method dynamically adjusts the power by measuring the power delivered from the driver, comparing the measured power to a desired power determined from the calibration information, and adjusting the driver configuration to reduce the error between the desired power and the measured power.

[0029] In various embodiments, the method dynamically adjusts power by measuring the electrical impedance of the load, calculating the transducer impedance based on the known impedances of other system components, calculating the required power from the driver to maintain the same amount of lost power at both ends of the real transducer impedance, and adjusting the driver configuration to meet the required power to reduce the error between the desired power and the measured power. In one embodiment, the power is dynamically adjusted whenever the treatment is being performed.

[0030] In one embodiment, the transducer calibration information also includes the power delivered to the transducer at each acoustic output level, the stored power information includes complex or real power components, the dynamic measurement of the power delivered from the driver is performed during ultrasonic irradiation of the tissue, and is verified against the power stored in the transducer calibration for the desired acoustic output level.

[0031] In one embodiment, the transducer calibration information also includes the power delivered to the transducer at each acoustic output level, the stored power information includes complex or real power components, the dynamic measurement of the power delivered from the driver is performed during ultrasonic irradiation of the tissue, and is verified against the power stored in the transducer calibration for the desired acoustic output level, the acoustic output power is generated by performing the measurement using force balance, the transducer calibration is stored as a reference table in a non-volatile memory chip inside the transducer, at least one of the voltage or current measured at the driver is adjusted using the transmission matrix represented by a two-port network between the treatment drive circuit output and the transducer, the calibration information is stored in a look-up table (LUT), and the target voltage is calculated from the calibration information and the desired acoustic output set at the clinic by interpolating values within one or more reference tables.

[0032] In various embodiments, a method for detecting the quality of acoustic coupling of a high-intensity focused ultrasound transducer through the skin surface by measuring the amount of back-reflected energy includes measuring the amount of back-reflected energy using a treatment transducer sensor, determining the distance between the piezoelectric treatment conversion bowl and the coupling surface, measuring a first output measurement value before reflection occurs from the coupling surface, measuring a second output measurement value after reflection occurs from the coupling surface, and calculating a differential calculation for determining the amount of back-reflected output.

[0033] In one embodiment, the amount of back-reflected energy is measured by a secondary transducer not used for treatment. In one embodiment, when calculating the change in output (forward minus reverse), the treatment temporarily stops until sufficient time has elapsed for the reflection from the coupling surface detected by either the secondary transducer or the treatment transducer to dissipate. In one embodiment, the treatment driver re-aligns and excites the treatment transducer when the reflected energy weakens below a threshold. In one embodiment, the high-intensity ultrasound transducer includes a multi-element array transducer, and calibration information is stored for each element within the array.

[0034] In one embodiment, the driver is housed within the system console, and the transducer is interchangeable between system consoles. In one embodiment, the transducer is interchangeable between handpieces, and the handpieces are interchangeable between consoles.

[0035] In various embodiments, a method for calibrating a high-intensity focused ultrasound transducer includes modeling a driver as a Thevenin equivalent source having a frequency-dependent source voltage and source impedance, storing calibration information including the source voltage and source impedance using the driver, measuring a transducer impedance, storing the transducer impedance in the calibration information on the transducer, calculating the power that would be delivered to the transducer by a driver using the source voltage and source impedance stored in the driver calibration for the load impedance stored in the transducer calibration, and treating the combined system as a voltage divider network.

[0036] In various embodiments, a method for measuring a transducer impedance includes calibrating a driver using one or more known reference impedances, measuring the transducer impedance at one or more frequencies and one or more amplitudes, adapting the measured transducer to a resonant circuit to calculate transducer parameters such as fixed capacitance, coupling coefficient, and radiation resistance, and using a characterization to determine transducer lifetime, operational success or failure, and required amplitude and phase.

[0037] In one embodiment, there is a fixed distance between the transducer and a predetermined treatment region. In one embodiment, the treatment beam is temporarily moved to an untreated region to determine the amount of backscatter from the treatment region using a differential method.

[0038] In various embodiments, an ultrasonic treatment system includes an ultrasonic probe including an ultrasonic treatment transducer adapted to apply ultrasonic treatment to tissue, and a power system configured to supply power to the ultrasonic treatment transducer, the power system including a power amplifier device and circuitry, the power amplifier device including at least one III-V semiconductor power transistor configured to operate at an efficiency of at least 75% at radio frequencies (RF) in the range of 200 kHz to 20 MHz.

[0039] In one embodiment, at least one III-V semiconductor power transistor is selected from the group consisting of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and AlGaN. In one embodiment, at least one III-V semiconductor power transistor is gallium nitride. In one embodiment, at least one III-V semiconductor power transistor is not one of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and AlGaN. In one embodiment, the power amplifier device includes a switched-mode amplifier design including a plurality of III-V semiconductor power transistors and a circuit configured to generate a digital waveform for driving the plurality of III-V semiconductor power transistors so as to drive a piezoelectric ultrasonic transducer. In one embodiment, the signal for driving the power transistor is generated by comparing the output of a sine-wave direct digital synthesis circuit with a DC voltage. In one embodiment, the output power is in the range of 30W to 100W. In one embodiment, the output power is in the range of 5W to 50W. In one embodiment, the circuit includes four power transistors configured in an H-bridge configuration. In one embodiment, the gate drive signal has a variable duty cycle used to control the harmonic content and power of the output signal. In one embodiment, the power amplifier converter supplies power to a radio frequency output signal output with an efficiency exceeding 75%. In one embodiment, the supply voltage to the power amplifier is modulated using a switched-mode DC-DC converter that reduces a fixed high voltage input to a low supply voltage. In one embodiment, the system includes two or more power amplifiers, and a single power amplifier is configured to drive a single piezoelectric conversion element of a high-intensity focused ultrasonic transducer. In one embodiment, the power amplifier is configured to drive the output at two or more different amplitudes. In one embodiment, the power amplifier is configured to drive the output at two or more different phases. In one embodiment, the phase and frequency are controlled by a direct digital synthesizer.In one embodiment, the system is configured to drive a transducer within an impedance range of 20 ohms to 120 ohms and a phase angle range of +45 degrees to -45 degrees.

[0040] In various embodiments, a power amplifier device for driving a high-intensity ultrasonic transducer includes a switched-mode amplifier design that includes at least one III-V semiconductor power transistor, and a circuit configured to generate a digital waveform for driving at least one III-V semiconductor power transistor.

[0041] In various embodiments, a device that includes a plurality of power amplifiers for driving a high-intensity ultrasonic transducer includes a switched-mode amplifier design that includes a plurality of III-V semiconductor power transistors, and a circuit configured to generate a digital waveform for driving the plurality of III-V semiconductor power transistors to drive a piezoelectric ultrasonic transducer.

[0042] In one embodiment, the III-V semiconductor power transistor is a gallium nitride field-effect transistor. In one embodiment, the power amplifier is configured to drive the output at two or more different amplitudes and / or the power amplifier is configured to drive the output at two or more different phases.

[0043] In various embodiments, a method for controlling the power of an ultrasonic system to deliver a desired amount of focused acoustic output by an ultrasonic transducer includes providing a power control system including a circuit including a control system microprocessor and a control system look-up table (LUT), providing an ultrasonic transducer including a transducer controller, a transducer microprocessor, and a transducer LUT, determining, using the transducer microprocessor, from the transducer LUT, an amount of power to be delivered to a load that is equivalent to a desired amount of acoustic output delivered to tissue by the ultrasonic transducer, determining, using the control system microprocessor, from the control system LUT, an amplitude of an electrical signal output from a power amplifier of the power system that would deliver an equivalent amount of power to the load, and setting the determined amplitude of the electrical signal output to at least one parameter of the power system output, wherein the load is in the range of 20 to 120 ohms. In one embodiment, the load is 50 ohms.

[0044] In various embodiments, an ultrasonic treatment system includes an ultrasonic probe including a housing that houses a piezoelectric-driven ultrasonic treatment transducer adapted to focus acoustic ultrasonic waves at a depth from the housing within a focal zone within tissue, and a power system configured to supply power to the ultrasonic treatment transducer, the power system including a power amplifier, and a power measurement system configured to monitor electrical output power from an output signal from the power amplifier, the power measurement system including a resistive current sensing circuit configured to monitor a current output from the power amplifier and a resistive voltage sensing circuit configured to monitor a voltage output from the power amplifier, the power measurement system being configured to monitor the electrical output power from the power amplifier over a frequency range of at least 2 octaves for the ultrasonic treatment transducer.

[0045] In various embodiments, a system for measuring radio frequency (RF) current and voltage of a drive circuit of a high-intensity focused ultrasound system includes a current sensing resistor in series with a load, a shunt voltage sensing resistor network in parallel with the load, and a power output voltage and current monitoring circuit (IQ demodulation circuit) having a local oscillator clock configured to synchronize with the phase and frequency of a signal driving a power amplifier and demodulate an output signal to a carrier frequency lower than the ultrasound drive frequency.

[0046] In one embodiment, the measurement system is configured to acquire multiple measurements with different relative phase shifts between a local oscillator and a power amplifier. In one embodiment, the local oscillator clock is generated from a directly digital synthesizer that is independently controlled. In one embodiment, the number of phase measurements is six. In one embodiment, the measurement system is configured to modify a gate drive signal to achieve a desired harmonic content in an output signal. In one embodiment, a method for determining the number of measurements is configured to appropriately measure harmonics by evaluating some of the lowest frequency harmonics within a passband that exceed a system noise floor.

[0047] In various embodiments, an ultrasound treatment system has one or more of the features described herein. In various embodiments, a power amplifier device for driving a high-intensity ultrasound transducer has one or more of the features described herein. In various embodiments, a method for controlling the power of an ultrasound system has one or more of the features described herein. In various embodiments, a system for measuring radio frequency (RF) current and voltage of a drive circuit in a high-intensity focused ultrasound system has one or more of the features described herein. In various embodiments, a method for calibrating a high-intensity ultrasound transducer has one or more of the features described herein. In various embodiments, a method for detecting the quality of acoustic coupling of a high-intensity focused ultrasound transducer through a skin surface has one or more of the features described herein.

[0048] Furthermore, the areas of applicability will become apparent from the description provided herein. It is to be understood that the description and specific examples are for illustrative purposes only and are not intended to limit the scope of the embodiments disclosed herein. In some embodiments, the system includes various features that exist as a single feature (as opposed to multiple features). For example, multiple features or components are provided in alternative embodiments. In various embodiments, the system includes, consists essentially of, or consists of one, two, three, or more embodiments of any of the features or components disclosed herein. In some embodiments, a feature or component is not included and can be disclaimed negatively from a particular claim, and the system does not have such a feature or component. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The drawings described herein are for illustrative purposes only and are in no way intended to limit the scope of the present disclosure. Embodiments of the present invention will be more fully understood from the detailed description and the accompanying drawings.

[0050]

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Mode for Carrying Out the Invention

[0051] The following description presents examples of embodiments and is not intended to limit the invention or its teachings, application areas, or uses. Throughout the drawings, corresponding reference numerals are to be understood as indicating like or corresponding parts and features. The description of specific examples presented in various embodiments of the invention is for illustrative purposes only and is not intended to limit the scope of the invention disclosed herein. Further, the listing of multiple embodiments having the described features is not intended to exclude other embodiments having additional features or other embodiments incorporating different combinations of the described features. Additionally, the features of one embodiment (such as a figure) can be combined with the description (and figures) of other embodiments.

[0052] Some embodiments for novel and / or inventive systems and methods are described herein, and those systems and methods provide high-efficiency control for directing power, voltage, current, and radio frequency (RF) signals to one or more focused energy-based systems. In various embodiments, the control system includes electronic devices, subsystems, and / or assemblies integrated on one or more printed circuit board assemblies. System architecture, circuits, modeling, design, implementation, and verification are directed towards improvements for providing high-efficiency power, voltage, and current for ultrasonic treatment systems. In various embodiments, the energy-based systems include compatible components (such as consoles, handpieces, transducer probe modules, etc.) that are calibrated to operate efficiently, effectively, and communicate with each other to provide a desired treatment result. The efficient and effective focusing performance of ultrasonic waves at a specific distance from an ultrasonic transducer is improved by reducing deviations, errors, and harmonics that can impede optimal performance. In some embodiments, the field of dermatology (including, for example, the fields of cosmetic and non-cosmetic plastic surgery) is provided. In other embodiments, non-dermatology fields (such as orthopedics, neurology, heart, etc.) are provided.

[0053] Overview of Ultrasonic Treatment SystemReferring to the explanatory diagrams of FIGS. 1A, 1B, and 1C, various embodiments of the ultrasonic treatment system 20 include a hand wand (e.g., a handpiece) 100, a module (e.g., a transducer module, a cartridge, a probe) 200, and a controller (e.g., a console) 300. In some embodiments, the cart 301 can provide mobility and / or positioning of the system 20 and can include wheels, a surface for writing or placing components, and / or a compartment 302 (e.g., a drawer, a container, a shelf, etc.) for storing or organizing components, for example. In various embodiments, the controller 300 can be adapted and / or configured to operate using the hand wand 100 and the module 200, as well as the overall functionality of the ultrasonic system 20. In various embodiments, a plurality of controllers 300, 300', 300'', etc. can be adapted and / or configured to operate using a plurality of hand wands 100, 100', 100'', etc. and / or a plurality of modules 200, 200', 200'', etc. In various embodiments, the controller 300 can include a system processor and various analog and / or digital control logic such as one or more of a microcontroller, a microprocessor, a field programmable gate array, a computer board, and related components, the related components including firmware and control software, and can be interfaced using input / output circuits and systems for user control and interface circuits, as well as communication, display, interface, storage, documents, and other useful functions. The system software operating on the system process can be configured to control initial settings, timing, level settings, monitoring, safety monitoring, and all other ultrasonic system functions for achieving user-defined treatment objectives, and / or can be configured. Further, the controller 300 can include various input / output modules such as switches, buttons, etc., which can be suitably configured to control the operation of the ultrasonic system 20, and / or can be configured.FIG. 2 is a schematic diagram of an ultrasonic system 20 coupled to an area of interest 10 (not shown) of a subject 500 (skin surface 501, epidermal layer 502, dermal layer 503, subcutaneous fat layer 505, superficial musculoaponeurotic system 507 (hereinafter referred to as "SMAS 507"), and muscle layer 509).

[0054] Overview of the ultrasonic controller As discussed herein, in various embodiments, the controller 300 can be adapted and / or configured to include, for example, a microprocessor with software and input / output devices, systems and devices for electronic and / or mechanical scanning, and / or multiplexing of transducers and / or transducer modules, systems for power delivery, systems for monitoring, systems for detecting the spatial position of probes and / or transducers and / or for multiplexing transducer modules, and / or, among other things, systems for processing user input and recording treatment results. In various embodiments, the controller 300 can be configured to supply radio frequency (RF) power to drive one or more ultrasonic transducers. In various embodiments, the controller 300 can include an RF therapy (RFTH) module that includes an electronic device and / or electronic subsystem configured to generate RF power over a desired range of RF power and over a desired range of frequencies to drive one or more ultrasonic transducers. This RFTH module can include a printed circuit board (PCB) assembly that includes a subsystem for delivering and monitoring an RF signal to drive one or more ultrasonic transducers. This PCB assembly can include one or more RF signal generators, one or more RF power amplifiers, one or more oscillators, one or more temperature monitors, one or more power monitors, one or more power supplies, one or more timing circuits, and / or other electronic components configured to generate an RF signal over a desired power range and over a desired frequency range, a system capable of measuring RF signal power, and / or a calibration system capable of predicting the RF power that will be delivered to one or more ultrasonic transducers.

[0055] FIG. 3 illustrates a block diagram of an implementation embodiment of an RFTH module that includes a drive subsystem 3000 configured to generate RF signals at a desired RF power and over a desired frequency range to drive an ultrasonic transducer. In one embodiment, the RFTH module can include eight drive subsystems configured to generate eight RF signals at a desired RF power and over a desired frequency range to drive eight ultrasonic transducers. In other embodiments, the number of drive subsystems of the RFTH module can be less than eight (e.g., 7, 6, 5, 4, 3, 2, 1), or nine or more (e.g., 9, 10, 11, 12, 13, 15, 20, or more).

[0056] The drive subsystem 3000 includes a power amplifier (PA) 3001 that generates an RF output signal having a desired frequency, phase, and amount of RF power. The drive subsystem 3000 can further include a power supply system 3011 configured to supply power to the power amplifier 3001. The generated RF signal can be directed to an on-board 50Ω load 3003 or an output connector 3005 connected to the ultrasonic transducers of the handwand 100 and / or module 200 for diagnosis and calibration. The drive subsystem 3000 further includes a power measurement system 3007 that monitors the electrical output power from the power amplifier to the ultrasonic transducer. The power measurement system 3007 can be configured to sample the complex voltage across the output connector 3005 and the current passing therethrough. In various embodiments, the IQ demodulator is a power output voltage and current monitoring circuit. The power measurement system 3007 includes an IQ demodulator that demodulates the RF signal to baseband using a synchronization clock. This can be useful for real-time high-resolution monitoring of the phase of the RF power from the output connector 3005 and / or for evaluation of the thermal dose delivered to the patient.

[0057] Some embodiments of an RFTH module that includes a plurality of drive subsystems 3000 can be configured to provide a phase-locked drive signal having a controllable frequency and phase to the plurality of drive subsystems 3000. For example, a clock distribution circuit 3010 that includes three 4-channel direct digital synthesizer (DDS) integrated circuits (ICs) can be used to provide a phase-locked drive signal having a controllable frequency and phase. Two of the three DDSs can provide drive signals to the power amplifiers 3001 of the plurality of drive subsystems 3000, while a third DDS provides a reference clock signal to a demodulator IC within a power measurement system 3007 for synchronous demodulation.

[0058] Since the exact operation of the RFTH module is important for patient safety, the RFTH module can include various health monitoring systems configured to ensure the exact operation of the RFTH module. For example, the RFTH module can include one or more temperature monitors 3009 that monitor the temperature at various parts of the RFTH module. In one embodiment of the RFTH module, the one or more temperature monitors can be configured to monitor the temperature at 32 different locations around the RFTH module. In various embodiments, the one or more temperature monitors 3009 can be configured to receive temperature measurements from one or more sensors disposed at various locations of the RFTH module. The RFTH module can include one or more power supply monitors 3013 for monitoring the voltage and / or current provided to the power amplifier 3001 by a power supply system 3011. In some embodiments, the RFTH module can include a controlled current limit (ICTRL) device 3015 that controls the maximum current supply provided to the power amplifier 3001. The RFTH module can include a relay monitor 3017 configured to ensure that various relays (e.g., relay 3018) switch when commanded to switch. The monitor can monitor the current and / or voltage of various low voltage sources and provide to enable / disable control and discharge circuits.

[0059] The RFTH module can include a board module controller (BMC) 3019, and the board module controller provides a communication interface with the system real-time controller (RTC) and receives data from the power measurement system 3007, the on-board health monitoring system, and the power supply monitoring system. The BMC 3019 can be configured to generate an anomaly whenever it detects an incorrect reading from the health monitoring system. These anomalies can be reported to the RTC and recorded in the on-board EEPROM device. The BMC 3019 can be programmed via the JTAG header 3021 or by the JTAG interface to the RTC.

[0060] The RFTH module can be configured to connect to the backplane of the controller 300 through a PCIe connector. The control of the power amplifier 3001 can be performed directly through the RTC via this PCIe connector. The RTC controls the amplitude of each channel and controls the frequency and phase through the control of the DDS. The ICs on the board are powered by a buck converter DC-DC power supply operating on a 24VDC master power supply and a low dropout regulator. In various embodiments, a separate 39VDC power supply can be included to power the power amplifier. This separate power supply can be enabled / disabled separately in various embodiments. Various innovative aspects of different components, circuits, and / or subsystems of the RFTH module are described in detail below.

[0061] Power amplifier Various embodiments of the power amplifier contemplated in the present application may be capable of providing high efficiency up to 100 W of RF power over a frequency range of 1.0 MHz to 12.0 MHz. For example, various embodiments of the power amplifier included within the RFTH module may supply RF power in the range of about 1 W to about 10 W, about 5 W to about 15 W, about 10 W to about 20 W, about 25 W to about 35 W, about 30 W to about 40 W, about 35 W to about 45 W, about 40 W to about 50 W, about 45 W to about 55 W, about 50 W to about 60 W, about 55 W to about 65 W, about 60 W to about 70 W, about 65 W to about 75 W, about 70 W to about 80 W, about 75 W to about 85 W, about 80 W to about 90 W, about 85 W to about 95 W, about 90 W to about 100 W, or any RF output power within any range / sub-range defined by any of these values over a frequency range of 1.0 MHz to 12.0 MHz. In some embodiments, the power amplifier may be configured to supply RF output power in excess of about 100 W.

[0062] Various embodiments of the power amplifier 3001 included within the RFTH module can be configured to operate over a wide frequency adjustment range. For example, various embodiments of the power amplifier can be configured to supply RF output power up to 100W over a frequency range spanning at least 2 octaves. For example, the power amplifier can operate over a wide range of frequency ranges / sub-ranges defined by any of the following: a frequency of approximately 1.0 MHz to approximately 5 MHz, approximately 2.5 MHz (e.g., 2.0 MHz, 2.2 MHz, 2.4 MHz, 2.6 MHz, 2.8 MHz, 3.0 MHz) to approximately 7.5 MHz (e.g., 7.0 MHz, 7.2 MHz, 7.4 MHz, 7.6 MHz, 7.8 MHz, 8.0 MHz), approximately 3.0 MHz (e.g., 2.5 MHz, 2.7 MHz, 2.9 MHz, 3.1 MHz, 3.3 MHz, 3.5 MHz) to approximately 9.0 MHz (e.g., 8.0 MHz, 8.2 MHz, 8.4 MHz, 8.6 MHz, 8.8 MHz, 9.0 MHz), approximately 3.5 MHz to approximately 10.5 MHz, approximately 4.0 MHz to approximately 8.0 MHz, approximately 5.0 MHz to approximately 10.0 MHz, approximately 4.0 MHz to approximately 12.0 MHz, approximately 6.0 MHz to approximately 12.0 MHz, or any range / sub-range of RF output power defined by any value between approximately 1W and approximately 100W. In various embodiments, the power amplifier can be configured to operate with at least 75% efficiency at various frequencies within the frequency range / sub-range defined by a value of approximately 1.0 MHz to approximately 12.0 MHz.

[0063] Various embodiments of the power amplifier 3001 included in the RFTH module can be configured to provide reliable operation by preventing short - circuit and open - circuit states. Various embodiments of the power amplifier included in the RFTH module can be optimized to drive a 50Ω load. Various embodiments of the power amplifier included in the RFTH module can be configured to drive a load with an impedance having a magnitude of about 20Ω to about 200Ω and a phase of about - 60 degrees to about 60 degrees. For example, various embodiments of the power amplifier can be configured to drive a transducer with an impedance in the range of 20Ω to 120Ω and a phase angle of + 45 degrees to - 45 degrees.

[0064] Semiconductor material (e.g., gallium nitride) field - effect transistor The power amplifier 3001 desirably achieves a power efficiency exceeding about 75% in the operating frequency range of 1.0 MHz to 12.0 MHz. Accordingly, various embodiments of the power amplifier 3001 can have a switched-mode design. A switched-mode amplifier can be classified as either a resonant device with zero-voltage switching (e.g., class E) or a device without zero-voltage switching (e.g., class D). Many embodiments of the power amplifier 3001 described in this application are configured to operate in the frequency range of 1.0 MHz to 12.0 MHz and employ a non-resonant switched-mode amplifier design. One embodiment of a switched-mode amplifier includes a switching circuit and a low-pass filter. The output of the switched-mode amplifier is a rectangular wave. After passing through the low-pass filter, the rectangular wave becomes more sinusoidal when harmonics above the cut-off frequency of the low-pass filter are removed. Most conventional metal-oxide semiconductor (MOS) field-effect transistor (FET) devices containing silicon may not be able to achieve a power efficiency exceeding 75% in the desired operating frequency range of 1.0 MHz to 12.0 MHz. However, electronic devices (e.g., transistors and / or FETs) containing high-efficiency transistors such as III-V semiconductor materials (e.g., III-V compound semiconductors obtained by combining group III elements (e.g., Al, Ga, In) with group V elements (e.g., N, P, As, Sb), such as gallium nitride (GaN), gallium arsenide (GaAs), gallium antimonide (GaSb), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), indium gallium arsenide (InGaAs), aluminum antimonide (AlSb), aluminum gallium arsenide (AlGaAs), aluminum gallium nitride (AlGaN), etc.) have an output capacitance and switching time at a given operating voltage that are approximately one order of magnitude smaller than the output capacitance of a silicon MOSFET. In some embodiments, GaN transistors are described, but in other contemplated embodiments, any of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and / or AlGaN transistors may be used.In one embodiment, only one semiconductor is used. Thus, the GaN FET can achieve a power efficiency of over about 75% in the frequency range of about 1.0 MHz to 12.0 MHz. The GaN FET includes a thin layer of GaN grown on a silicon wafer. The GaN FET has several advantages, including, but not limited to, (i) high breakdown voltage that may be attributed to GaN, a wide-bandgap semiconductor, (ii) high operating temperature that may be attributed to GaN, a wide-bandgap semiconductor with a high potential barrier, (iii) high current density that may be attributed to high electron mobility, (iv) fast switching that may be attributed to high electric field saturation velocity and high electron mobility, (v) a smaller on-resistance compared to conventional silicon (Si) devices that may be attributed to high electron mobility, and (vi) a smaller output capacitance compared to conventional Si devices that may be attributed to high electron mobility. For example, an FET made of GaN can exhibit input and output capacitances that are approximately 10 times smaller for the same current handling ability as a silicon FET. This feature enables the GaN FET to operate efficiently at much higher frequencies than a silicon FET. Thus, the GaN FET can achieve a power efficiency of over about 75% in a switch-mode RF amplifier over the desired operating frequency range of 1.0 MHz to 12.0 MHz.

[0065] Transformer for transmission line A GaN FET may have a low output impedance (e.g., less than 100 mΩ). An RFTH module including a GaN FET is configured to drive one or more ultrasonic transducers having an impedance (e.g., 50 Ω impedance) in the range of 20 Ω to 200 Ω with respect to the RFTH module. In various embodiments of the RFTH module, a transmission line transformer is used to match the input impedance of the GaN FET to the impedance presented by one or more ultrasonic transducers. FIG. 4 illustrates an embodiment of a transmission line transformer that can be used to match the impedance of a GaN FET to the impedance presented by one or more ultrasonic transducers. The embodiment of the transmission line transformer shown in FIG. 4 is a Guanella type transmission line having an impedance ratio of 4:1. This transmission line transformer includes a set of common mode chokes 4001a, 4001b, 4001c, and 4001d that are connected in parallel on the low impedance side (e.g., the side facing the GaN FET device 4005) and in series on the high impedance side (e.g., the side facing the load 4003). The common mode chokes 4001a - 4001d can include wires wound on a ferrite core. The positive current 2I flowing out of the power amplifier 3001 having an output voltage V g branches into a current I through the common mode choke 4001d and a current I through the common mode choke 4001b. The common mode chokes are configured such that only differential signals can pass through. Thus, the positive current in the common mode choke 4001b creates a negative current in the common mode choke 4001a that returns the current in the common mode choke 4001d. Since the current 2I flows out of the left side of the transmission line transformer and the current I flows through the load 4003, by conservation of energy, the voltage across the load 4003 must be 2V g . This is the basic principle of operation of the Guanella transmission line transformer.

[0066] The embodiment of the Guanella transmission line transformer shown in FIG. 4 provides a turns ratio of 2:1, resulting in an impedance ratio of 4:1. The higher the impedance ratio, the more common mode chokes can be added in parallel on the left side and in series on the right side. Further, the common mode chokes do not have to be on different cores. As long as appropriate attention is paid to the winding direction to ensure that the common mode magnetic fields from different winding pairs do not cancel each other out, the windings can all be wound on the same core. Various embodiments of the power amplifier 3001 include a Guanella transmission line transformer having three pairs of windings on a single Amidon FT-87A-43 ferrite core. These three pairs of windings can include bifilar windings that can advantageously minimize or reduce parasitic capacitance. Further, each pair of bifilar windings can exhibit a large common mode impedance and a small differential mode impedance. Embodiments of such a Guanella transmission line transformer can provide an impedance ratio of 9:1 that converts a 50Ω output impedance to a 5.6Ω impedance at each transistor. By converting the load impedance, which is nominally 50Ω on the side facing the GaN FET, to 5.6Ω, embodiments of the Guanella transmission line transformer can provide a load that can drive the GaN FET more efficiently than directly driving a 50Ω load. This may be due to the secondary increase in the charging loss of the output capacitance experienced as the voltage increases. Further, by increasing the output voltage, embodiments of the Guanella transmission line transformer can enable a large output voltage exceeding 200Vpp to be generated from a low voltage power supply (e.g., nominally 39VDC).

[0067] Further, by providing a balanced-to-unbalanced conversion, the Guanella transmission line transformer can enable the use of a balanced H-bridge driver to drive an ultrasonic transducer using a ground-referenced signal. The balanced H-bridge design provides an effective doubling of the drive voltage and removes even-order harmonics from the output waveform due to the left-right symmetry of the bridge. The balanced H-bridge driver design will be considered in detail below.

[0068] H - bridge driver Various embodiments of the power amplifier 3001 including GaN FETs can be driven by an H - bridge driver. The H - bridge design topology is illustrated in FIG. 5A. The H - bridge operates by placing a load 5003 at an intermediate point between a first pair of FETs 5001a and 5001b and a second pair of FETs 5001c and 5001d. FETs that are diagonally located on the bridge (e.g., 5001a and 5001d, or 5001b and 5001c) are configured to switch to the same state. As shown in FIG. 3B, in the first switching configuration, FETs 5001a and 5001d are configured to be in a closed configuration, while FETs 5001b and 5001c are configured to be in an open configuration. In the first switching configuration, current is driven from left to right through the load 5003. As shown in FIG. 3C, in the second switching configuration, FETs 5001b and 5001c are configured to be in a closed configuration, while FETs 5001a and 5001d are configured to be in an open configuration. In the second switching configuration, current is driven from right to left through the load 5003. Due to the left - right symmetry of the H - bridge design, the falling edge of the signal can have substantially the same shape as the rising edge of the signal. This property conveniently suppresses even - order harmonics in the signal and leaves only odd - order harmonics.

[0069] Optimize the H-bridge driver design to achieve an average power efficiency exceeding approximately 75% in the frequency range of about 1.0 MHz to 12.0 MHz. For example, the average power efficiency achieved by various embodiments of the power amplifier 3001 including GaN FETs can be greater than about 80%, greater than about 85%, greater than about 90%, greater than about 95%, and / or less than about 100% in the frequency range of about 1.0 MHz to 12.0 MHz. The optimized H-bridge design can be configured to achieve a peak power efficiency exceeding about 85% in the frequency range of about 1.0 MHz to 12.0 MHz. For example, the average power efficiency achieved by various embodiments of the power amplifier 3001 including GaN FETs can be greater than about 90%, greater than about 95%, and / or less than about 100% in the frequency range of about 1.0 MHz to 12.0 MHz.

[0070] The functional requirement of the ultrasonic treatment system 20 described herein is to generate an output signal that can operate at any frequency within a wide range that is instantaneously narrowband but spans at least 2 octaves (e.g., spans at least 3 - 4 octaves). For example, the ultrasonic treatment system 20 described herein can be configured to generate an output signal at a fundamental frequency f0 having a value in the frequency range of 1.0 MHz to 12.0 MHz and having a bandwidth of the output signal (e.g., 3 dB bandwidth). Without relying on any particular theory, the output from the H-bridge driver is a filtered square wave that includes a signal component at the fundamental frequency f0 and components at higher harmonics. Higher harmonics can distort the RF signal output from the power amplifier 3001 and / or can affect the measurement accuracy of the RF power of the output RF signal. Further, when one or more ultrasonic transducers are driven with a signal containing harmonics, the acoustic radiation can also potentially contain harmonics. Due to the frequency dependence of ultrasonic absorption in tissue, this can, as a result, heat the vicinity of the intended focus and, in some cases, pose a risk to the patient. Further, harmonics at frequencies above 30 MHz can pose a risk of generating radioactive emissions that exceed the limits defined by the basic safety and performance of medical devices.

[0071] Therefore, it is desirable to reduce the amplitude of the harmonics in the signal output from the H-bridge driver below the threshold value. As one approach for reducing the amplitude of the harmonics in the signal output from the H-bridge driver, it may include providing a low-pass filter for removing the harmonics. However, providing a low-pass filter that filters out harmonics with lower values of the frequency f0 (e.g., 1.0 MHz to about 6.0 MHz) may result in a reduction in the amplitude of the output RF signal having a fundamental frequency f0 greater than the cut-off frequency of the low-pass filter. Therefore, in order to enable efficient operation of the power amplifier 3001 over the entire frequency range from 1.0 MHz to 12.0 MHz, the cut-off frequency of the low-pass filter must be greater than about 12.0 MHz, such as 16.0 MHz for example. However, a low-pass filter having a cut-off frequency exceeding about 12.0 MHz cannot attenuate the amplitude of the harmonics with lower values of the frequency f0 (e.g., 1.0 MHz to about 6.0 MHz). Therefore, when the power amplifier 3001 is configured to operate at a fundamental frequency f0 having a value between about 1.0 MHz and about 6.0 MHz, a plurality of harmonics may be present within the passband.

[0072] As discussed above, the H-bridge design uses an inverted symmetric waveform - the negative part of the waveform looks the same as the positive part of the waveform - to remove higher even harmonics (e.g., signals of 2f0, 4f0, 6f0, or other higher even harmonics). To suppress higher odd harmonics (e.g., signals of 3f0, 5f0, 7f0, or other higher odd harmonics), the H-bridge design uses a unique drive signal scheme where the duty cycles of the positive part and the negative part of the waveform are selected to suppress higher odd harmonics. FIG. 6 shows the drive signal generated by the H-bridge when the duty cycles of the positive part and the negative part of the waveform are set to 0.3. FIG. 7 shows the change in the amplitude of higher odd harmonics for different duty cycles of the positive part and the negative part of the waveform. From FIG. 7, it can be seen that the fundamental power increases as the duty cycle increases and reaches its peak value at a duty cycle of 50%. Therefore, the duty cycle can be used to modulate the output power at the fundamental frequency. Further, from FIG. 7, it can be seen that various harmonics reach their minimum values at various duty cycle values. Therefore, if the suppression of a particular harmonic is desired, there are one or more duty cycle values at which that harmonic is significantly suppressed. Further, at a duty cycle of 0.333, both the third and ninth harmonics are suppressed. This is useful because the third harmonic is the non-zero harmonic with the lowest frequency and is therefore least likely to be suppressed by a low-pass filter. Therefore, by selecting a duty cycle of approximately 0.3, the third harmonic of the drive signal can be advantageously suppressed. Without loss of generality, the positive and negative duty cycles of the waveform are selected to have the same value to suppress even harmonics. Further, from FIG. 7, it can be seen that the minimum total harmonic distortion occurs at a duty cycle of 0.386.In addition to controlling the duty cycle of the positive part of the waveform and the negative part of the waveform output from the H-bridge to suppress higher odd harmonics, a low-pass filter having a cut-off frequency of about 80% or more of the maximum frequency of operation of the power amplifier is provided to suppress higher odd harmonics. For example, in various embodiments of an ultrasonic treatment system configured to operate at a maximum frequency of 12.0 MHz, a low-pass filter having a cut-off frequency of about 12.0 MHz or higher (e.g., about 10 MHz to about 16.0 MHz) is used to remove higher odd harmonics having frequencies above the cut-off frequency.

[0073] Consider an embodiment of an ultrasonic treatment system configured to operate in a frequency range from about 1.0 MHz to about 12.0 MHz. Further, consider that the GaN FET of the power amplifier included in such an embodiment of the ultrasonic treatment system is driven by an H-bridge driver that selects a duty cycle of the positive part of the waveform and the negative part of the waveform (e.g., a duty cycle of about 0.33) to suppress the third harmonic. Further, consider that the power amplifier includes a low-pass filter having a cut-off frequency of about 16 MHz (e.g., a fifth-order Chebyshev filter having 0.1 dB ripple). FIGS. 8A-8D show signals output from such an embodiment of the power amplifier at 2.0 MHz, 4.0 MHz, 7.0 MHz, and 12.0 MHz. In FIGS. 8A-8D, reference numerals 8001a, 8003a, 8005a, and 8007a refer to the output signals before the low-pass filter, and reference numerals 8001b, 8003b, 8005b, and 8007b refer to the output signals after the low-pass filter. It can be seen that the output signal after the low-pass filter in FIG. 8A is distorted from a sine wave shape, indicating that the low-pass filter allows some higher odd harmonics in the passband at a frequency of 2.0 MHz. As can be seen from the nearly sine-wave signal output after the low-pass filter in FIG. 8B, at a frequency of 4.0 MHz, the contribution of higher odd harmonics is significantly reduced. At frequencies of 7.0 MHz and 12.0 MHz, as can be seen from the sinusoidality of the signal output after the low-pass filter, higher odd harmonics are almost removed.

[0074] Accordingly, various embodiments of the H-bridge driver configured to drive the GaN FET of the power amplifier 3001 operate in a duty cycle having a low-pass filter designed to suppress the third harmonic and having a cut-off frequency designed to suppress higher odd harmonics having frequencies above about 12.0 MHz.

[0075] The H-bridge drive signal is generated from an analog comparison between a DC signal set by a digital-to-analog converter (DAC) and a pair of phase-shifted sine wave signals from the balanced differential output stage of a direct digital synthesizer (DDS). FIG. 9 shows a schematic diagram of a comparator circuit used to generate two drive waveforms. In FIG. 9, battery 9001 represents a DC voltage source, and transformer 9003 provides a balanced signal.

[0076] FIG. 10 schematically shows an H-bridge drive signal plotted on the same graph with waveform 10001a representing a waveform generated by in-phase sine waves and waveform 10001b representing a waveform generated by phase-shifted sine waves. The two drive signals represented by waveforms 10001a and 10001b are delayed by 180 degrees.

[0077] The advantage of the H-bridge design represented by the circuit of FIG. 9 is that this design can provide a convenient mechanism for modulating the gate drive duty cycle by changing the value of the DC signal corresponding to the output from battery 9001. In the RFTH module, this DC signal is controlled by a 12-bit DAC and can modulate the duty cycle from 0% to 50%. As discussed above, control of the duty cycle provides many advantages, including but not limited to adjusting the power level of the fundamental frequency and suppressing the amplitude of higher-order harmonics. Further, setting the gate drive duty cycle to 0% or 100% can provide a convenient method for preventing the H-bridge FETs from turning off during TCP for measuring VSWR sensitivity. Further, setting the gate drive duty cycle to 0% or 100% can provide a mechanism for disabling unused channels during testing.

[0078] Protection circuit FIG. 11A shows a simplified circuit diagram of a switch-mode power amplifier 3001 including an H-bridge formed by four GaN FETs 11001a, 11001b, 11001c, and 11001d that drive the balanced side of a 1:9 Guanella transmission line transformer 11003. GaN FETs can tend to be damaged from their relatively delicate gate-channel insulation layers and inductive spikes due to the small range of breakdown voltages. Thus, a protection circuit including 5.6V zener diodes 11005 and fast Schottky diodes 11007 in parallel with the H-bridge high-voltage side FET gates 11001c and 11001d can ensure that the threshold turn-on voltage V does not exceed 5.6V on the positive side and that the gate does not exceed 0.3V less than the power supply on the negative side. An embodiment of such a protection circuit is shown in FIG. 11B. Such a protection circuit can protect the GaN FETs against inductive spikes, and a short-circuit surge (or discharge) exceeding 20A can be tolerated for a period of 1 ms or more (e.g., 2 ms, 5 ms, 10 ms, or more). For example, the Schottky diode 11007 can ensure that the gate voltage is clamped to the power supply voltage when an inductive spike that generates a negative V GS occurs. In some embodiments, in the absence of the Schottky diode 11007, a current surge exceeding 8A (which can be encountered in a short-circuit event) can potentially cause the GaN FETs to fail.

[0079] Amplitude control Various embodiments of the power amplifier 3001 can include a voltage-controlled buck converter to provide amplitude control. An embodiment of the voltage-controlled buck converter is shown in FIG. 11C. The voltage-controlled buck converter may also be referred to as a feedback-controlled buck converter. The amplitude can be controlled by injecting current into the summing node of the voltage-controlled buck converter that gives a stepwise and / or low-bandwidth modulation (e.g., about 3 kHz or less) at the output of the voltage-controlled buck converter. In one embodiment, the deployed system uses discrete amplitude changes. In one embodiment, discrete amplitude changes are important for controlling the power in any therapy-mode - image processing mode scenario. The low-bandwidth modulation output from the voltage-controlled buck converter is provided to an H-bridge that impart low-bandwidth modulation to the RF power output from the power amplifier. Without loss of generality, the low-bandwidth modulation output from the voltage-controlled buck converter can change the drive voltage provided to the FET, which can change the voltage applied to the load when the high-side FET is on. This will be explained in more detail below.

[0080] In one embodiment, the H-bridge output is modulated by varying the voltage supplied to the drain of the high-side FET, and that voltage is applied to the load when the high-side FET is on. In one embodiment, the H-bridge output is modulated by varying the voltage supplied to the drain of the high-side FET, and that voltage is applied to the load when the high-side FET is closed. In some embodiments, this voltage is generated as the output from a step-down DC-DC buck converter that can efficiently step down the voltage from a high-voltage power supply in a stepped manner. The output voltage of the buck converter is controlled by the duty cycle and frequency of the switching event. Some embodiments of the basic converter circuit include a feedback loop where the output is measured and compared against a threshold. When the output drops below the threshold, the buck converter changes its switching operation to deliver more power to the load. In some embodiments of a power amplifier that uses a buck converter to set the output amplitude, the output of the buck converter is controlled by injecting current into the summing input of the feedback loop. When more current is delivered to the summing node, less current is provided by the output of the buck converter, and the buck converter drops the output voltage. Conversely, when less current is delivered to the summing node, more current is provided by the output of the buck converter, and that additional current raises the output voltage. The voltage of the output of the buck converter can rise until the voltage at the summing node exceeds the threshold.

[0081] Power Measurement System As discussed above, various embodiments of the RFTH module described herein include a power measurement system 3007 configured to monitor the power output from the power amplifier 3001 to one or more ultrasonic transducers. In various embodiments, this power measurement system 3007 can be configured to measure the power of RF signals output from the power amplifiers of different drive subsystems 3000 of the RFTH module. Further, the power measurement system 3007 can also be configured to measure the relative phase between RF signals output from the power amplifiers 3001 of different drive subsystems 3000.

[0082] The power measurement system 3007 can be implemented as a high-density printed circuit board (PCB) design. This PCB design can be configured to have a small size and / or low heat dissipation. Various embodiments of the power measurement system 3007 can be configured to measure RF signals output from a power amplifier 3001 delivered to a wide range of impedances Z having a magnitude |Z| of 20 Ω to 200 Ω and a phase angle ∠ of -60° to 60°. For example, various embodiments of the power measurement system 3007 can be configured to measure RF signals output from a power amplifier 3001 delivered to a wide range of impedances Z having a magnitude |Z| of 20 Ω to 120 Ω and a phase ∠ of -45° to 45°. Various embodiments of the power measurement system 3007 can be configured to measure the power of RF signals output from power amplifiers of different drive subsystems 3000 with an accuracy of approximately ±0.5 dB. Various embodiments of the power measurement system 3007 can be configured to measure the power of RF signals output from power amplifiers of various drive subsystems 3000 with an accuracy of approximately ±0.5 dB even if there is a significant contribution to the RF signals output from higher-order harmonics. Various embodiments of the power measurement system 3007 can be configured to operate over a wide frequency range. For example, the power measurement system 3007 can be configured to operate over at least the same frequency range as the power amplifier 3001. For example, the power measurement system 3007 can be configured to operate at a wide range of frequencies from approximately 1.0 MHz to approximately 12.0 MHz.

[0083] Various embodiments of the power measurement system 3007 can include resistive current sensing and voltage sensing components. For example, various embodiments of the power measurement system 3007 can use a small-signal transformer for common-mode rejection. The use of resistive current sensing and voltage sensing components can have several advantages compared to magnetic devices (e.g., RF directional couplers, RF circulators, and other magnetic devices) that are more commonly used for monitoring RF power, including, but not limited to, smaller circuit size, lower cost, less heat dissipation, and / or improved interference tolerance.

[0084] In resistive current sensing and voltage sensing components, parasitic reactance effects may be important, but most parasitic reactance effects can be calibrated and removed from the measurement values. The power measurement system 3007 can include a differential measurement method that includes a broadband small-signal RF transformer, as shown in FIG. 12. This differential measurement method can remove a large common-mode component from the signal and can advantageously isolate the measurement circuit from the current sensing resistor 12001. This differential measurement method can provide tolerance to interference resulting from capacitive and magnetic coupling between the components of the power measurement system 3007 and the components of the power amplifier 3001. In particular, the magnetic field radiated from the power transformer, as well as the parasitic mutual capacitances and inductances on the PCB, can couple to the amplifier input. This interference is common-mode and will generate approximately the same coupling at the two inputs of the differential amplifier. Therefore, using a differential amplifier can advantageously reduce / remove the common-mode coupling at the two inputs of the differential amplifier while enhancing the differential current or voltage signal.

[0085] The power measurement system 3007 can include a heterodyne IQ demodulator (e.g., the demodulator AD8333 commercially available from Analog Devices). In various embodiments of the RFTH module, each drive subsystem 3000 can include a heterodyne IQ demodulator configured to receive the sampled current and voltage waveforms of a portion of the RF signal output from a power amplifier included within that drive subsystem 3000.

[0086] FIG. 13 shows one embodiment of the power measurement system 3007. As shown in FIG. 13, a portion of the output from the power amplifier 3001 is measured by resistive current sensing and voltage sensing components arranged in a differential measurement scheme shown in block 13003. The outputs from the resistive current sensing and voltage sensing components within block 13003 are input to the heterodyne IQ demodulator 13000. The heterodyne IQ demodulator 13000 includes a local oscillator (LO) clock 13001, current demodulator elements 13005a and 13005b, voltage demodulator elements 13005c and 13005d, filtering elements 13007a, 13007b, 13007c, and 13007d, and analog-to-digital converters (ADCs) 13009a, 13009b, 13009c, and 13009d. The heterodyne IQ demodulator 13000 is configured to operate at any frequency.

[0087] The heterodyne IQ demodulator 13000 can provide magnitude and phase measurements of the RF signal output from the power amplifier 3001. The heterodyne IQ demodulator 13000 can be configured to perform measurements in the baseband where the measurements are not subject to interference. The heterodyne IQ demodulator 13000 can potentially include high bit depth and slow sampling rate ADCs that can reduce cost, increase accuracy, and enable multiplexing of various RF channels. The low-pass filter of the IQ demodulator 13000 can enable narrowband filtering that can be independent of the frequency of the RF signal over a wide frequency range.

[0088] Figure 14 shows a block diagram of the AD8333IQ demodulator commercially available from Analog Devices. The IQ demodulator 13000 is configured to mix the sampled current and voltage waveforms down to baseband, such that those waveforms can be digitized using high-resolution analog-to-digital converters (e.g., ADCs 13009a - 13009d). The IQ demodulator can be configured to demodulate the input signal in a phase-sensitive manner, such that the phase of the RF signal relative to the reference clock can be faithfully reproduced as the phase of the analysis signals, which are the two outputs of the IQ demodulator within the narrow bandwidth limits, for the real and imaginary components.

[0089] The IQ demodulator 13000 is a two-channel device that accepts two input RF signals and an input from a local oscillator (LO) clock 13001. For demodulation to baseband, the frequency of the LO 13001 is four times the frequency of the RF signal. For example, if the power amplifier 3001 is operating at a frequency

Number

Number

[0090] The IQ demodulator 13000 uses the input from the LO clock 13001 to generate

Number

[0091] FIG. 15 shows two internal clocks generated by one embodiment of the demodulator 13000. In FIG. 15, waveform 15001 shows the signal output from the power amplifier 3001, waveform 15003 shows the output of the LO clock 13001, waveform 15005 shows the I clock, and waveform 15007 shows the Q clock. As will be discussed below, the I and Q clocks can be used to demodulate and reconstruct the signal output from the power amplifier 13000.

[0092] The demodulator functions by causing the I and Q clocks to control whether the power amplifier 3001 that amplifies the RF signal is inverted. This operation is equivalent to multiplying the RF signal output from the power amplifier 3001 by a rectangular wave having a maximum value of 1 and a minimum value of -1, as shown in FIG. 16.

[0093] This operation generates two output signals, one for the I clock and the other for the Q clock. In the case of a sine wave signal that is in phase with the I clock, when mixed with the I clock, a signal with a positive average value is generated. In contrast, when mixed with the Q clock, a signal with an average value of zero is generated. FIG. 17 shows the I and Q demodulation of a sine wave signal. In FIG. 17, signal 17001 is the output of the sine wave signal mixed with the I clock, and signal 17003 is the output of the sine wave signal mixed with the Q clock.

[0094] The average value of the mixed signals is exactly their baseband value and can be extracted by low-pass filtering. In the case of a narrowband signal such as a sine wave, the I and Q outputs are the real and imaginary parts of the analyzed signal, and its phase

Number

Number

[0095] The IQ demodulator employs a phase shift harmonic cancellation method that enables measurement of the magnitude and phase of the fundamental frequency component in the presence of higher-order harmonics. In the phase shift harmonic cancellation method, the heterodyne LO clock 13001 is discretely phase-shifted with respect to the RF signal output from the power amplifier 3001 to generate a set of LO phase-dependent IQ samples. Those samples are reconstructed into fundamental wave power and harmonic power using a linear inverse transform. This will be explained in more detail below.

[0096] As discussed above, the power amplifier 3001 is configured to operate in a wide frequency range spanning at least 2 octaves. For example, as discussed above, the power amplifier 3001 is configured to operate in a wide frequency range from approximately 1.0 MHz to approximately 12.0 MHz. To enable the broadband operation of the power amplifier 3001, the low-pass filter can have a cut-off frequency of approximately 16 MHz or higher. Therefore, the higher harmonics of the lower operating frequencies (e.g., operating frequencies from approximately 1.0 MHz to approximately 6 MHz) will be within the passband of the low-pass filter, and thus will necessarily affect the frequency bandwidth of the power amplifier 3001 even after filtering. As an example of this, FIG. 18A shows an oscilloscope trace of the output from the power amplifier 3001 operating at an operating frequency of approximately 1.0 MHz to a 10 - 100 ohm (e.g., 25 ohm, 50 ohm, 75 ohm) load, and FIG. 18B shows an oscilloscope trace of the output from the power amplifier 3001 operating at an operating frequency of approximately 12.0 MHz to a 50 ohm load. Traces 18001a and 18001b respectively show the output waveforms at the two operating frequencies. At 12.0 MHz, all higher harmonics exceeding the cut-off frequency of the low-pass filter (e.g., 16 MHz) are removed, and thus the output waveform becomes a clean sine wave. However, at 1.0 MHz, some harmonics are within the passband, and thus the waveform becomes non-sinusoidal. The presence of higher harmonics can affect the accuracy with which the amplitude and phase of the output RF signal are measured, as will be discussed in detail below.

[0097] Due to the presence of harmonics, the output from the power amplifier 3001 cannot be considered narrowband. Conversely, the output of the power amplifier 3001 is composed of the sum of several narrowband signals having frequencies centered around the harmonic n×ω0, where n is an integer and ω0 is the fundamental frequency.

[0098] Therefore, the RF signal at the output of the power amplifier 3001 can be represented as a Fourier expansion given by the following equation (1).

Number

[0099] As will be discussed in detail below, the power assurance circuit configured to measure the amplitude and phase of the RF signal output from the power amplifier includes an IQ demodulator. Without relying on any specific theory, the operation of the IQ demodulator can be considered to multiply the RF power from the power amplifier 3001 by a rectangular wave and then perform low-pass filtering. The rectangular wave includes a signal component at the fundamental frequency and signal components at the harmonics of the fundamental frequency, and can be expressed as a Fourier expansion given by the following equation (2).

Number

[0100] Whenever both the RF power of the power amplifier 3001 and the rectangular wave signal have harmonic components, multiplication will mix the harmonic components into the baseband, that is, the difference frequency will be 0 Hz. FIG. 19 shows the magnitude of the fast Fourier transform (FFT) of the RF signal at the low-frequency end of the passband (normalized by a fundamental frequency of 1 MHz) and the magnitude of the fast Fourier transform (FFT) of the rectangular wave. In FIG. 19, waveform 19001 shows the FFT of the RF signal, and waveform 19003 shows the FFT of the rectangular wave. It can be seen from FIG. 19 that the fundamental wave, the fifth and seventh harmonics of the RF signal are shown. The rectangular wave has significant components at all odd harmonics. The harmonics at which both the rectangular wave and the RF signal have non-zero magnitudes in the FFT will affect the measured baseband signal.

[0101] The IQ demodulator of the power assurance circuit can be regarded as having I and Q local oscillators. The outputs from the I and Q local oscillators can be regarded as rectangular waves. Therefore, the outputs from the I and Q local oscillators can be Fourier-expanded as shown in equations (3a) and (3b).

Number

Number

Number

[0102] After mixing and low-pass filtering, both the I and Q local oscillators, as well as the harmonics of the RF signal, will affect the I and Q baseband signals as shown in Equations (4a) to (4d).

Number

Number

Number

Number

[0103] Therefore, the baseband signal depends not only on the Fourier amplitude at the fundamental frequency but also on all non-zero odd harmonics of the RF signal.

[0104] Therefore, in the presence of harmonics, the measured I and Q values may not return the correct phase or amplitude. Further, due to harmonics, the measured signal amplitude may depend on the phase between the I and Q local oscillators and the RF signal. This can result in a system error that may change when the beamforming delay changes. This beamforming delay may include the phase delay introduced between different channels to obtain the desired focusing effect from the multi-element transducer. For example, the error associated with this effect can be up to 6% of the voltage and current amplitudes and ±3 degrees with respect to the phase. This can result in significant inaccuracies in the measured voltage and / or phase.

[0105] For example, one way to reduce the inaccuracies in the measured voltage and / or phase of the output RF signal from the power amplifier 3001 includes correcting the amplitude and phase of some of the RF signals output from the power amplifier 3001 received by the power assurance circuit 3007 to remove the influence of harmonics. The amplitude and phase of some of the RF signals output from the power amplifier 3001 received by the power assurance circuit 3007 are corrected by obtaining I and Q data at a plurality of phase shifts of the I and Q clocks with respect to some of the RF signals output from the power amplifier 3001 received by the output assurance circuit 3007. The collection of I and Q data measured at N different phase offsets is sufficient to cancel the influence of the first N harmonics, but more measurements may be useful in obtaining a better estimate of the harmonics in the presence of noise. In many embodiments, the influence of the harmonics can be reduced to a level below the system noise floor when six different phase offsets are measured.

[0106] Thus, one way to reduce the impact of harmonics is to measure the I and Q data of the internal I and Q clock phases at 0°, 15°, 30°, 45°, 60°, and 75° for a portion of the RF signal output from the power amplifier 3001 received by the power assurance circuit 3007. In some embodiments, the input local oscillator (LO) clock included within the power assurance circuit 3007 can have a frequency four times higher than the internal clock. Thus, the phase of the input LO clock can be four times larger than the phases of the I and Q clocks. For example, when the I and Q clock phases are 0°, 15°, 30°, 45°, 60°, and 75° for a portion of the RF signal output from the power amplifier 3001 received by the power assurance circuit 3007, the phase of the input LO clock can be 0°, 60°, 120°, 180°, 240°, and 300° for a portion of the RF signal output from the power amplifier 3001 received by the power assurance circuit 3007.

[0107] FIG. 20 illustrates six phase-shifted sets of I and Q clocks used to demodulate a non-sinusoidal drive signal according to the method discussed above. After mixing the demodulator outputs, as shown in FIG. 21, twelve signals can be used to reconstruct the RF signal output from the power amplifier 3001.

[0108] The relationship between the I and Q values measured at these different phases and the correct Fourier amplitudes of the signal at each harmonic is linear, and thus, the Fourier amplitude of the RF input signal can be obtained from the I and Q samples measured at six phases via matrix multiplication.

[0109] Since I and Q are orthogonal components, when the I samples are obtained at a set of six phases evenly distributed in 15° steps in the range of 0° to 75° (e.g., 0°, 15°, 30°, 45°, 60°, 75°), the Q samples will be phase-shifted by 90° from the I samples. For example, the Q samples will be 90°, 105°, 120°, 135°, 150°, 165°.

[0110] Utilizing the inversion symmetry of the signal, the signal output from the power amplifier 3001 can be represented by the following equation (5).

Number

Number

Number

[0111] Therefore, six phases ranging from 0° to 180° are appropriate for the reconstruction of the RF signal output from the power amplifier 3001.[[]]END]]

[0112] According to the inversion symmetry, only the odd Fourier components become non - zero. Therefore, the first, third, fifth, seventh, ninth, and eleventh harmonics become non - zero. Therefore, the discrete Fourier transform (DFT) coefficients of the non - zero odd - order harmonics are calculated to reconstruct the RF signal output from the power amplifier 3001. In one method of reconstructing the RF signal output from the power amplifier 3001, a matrix that maps 12 measured I and Q sample values to the real and imaginary parts of the DFT of the RF signal output from the power amplifier 3001[[]]END]]

Number

Number

[0113] In Equation (6), A n is the complex Fourier coefficient of the nth harmonic.

[0114] matrix

Number

Number

Number

Number

Number

[0115] In many embodiments, the matrix

Number

[0116] Once the Fourier components A n are obtained, they can be used to reconstruct the waveform according to the following Equation (9).

Number

[0117] Figures 22A to 22C show an example in which a power guarantee circuit reconstructs an RF signal at three different frequencies output from a power amplifier 3001 by reducing the contribution from higher-order harmonics described in this specification. Figure 22A shows the reconstruction of the RF signal at a frequency of 1.0 MHz. Figure 22B shows the reconstruction of the RF signal at a frequency of 2.0 MHz. Figure 22C shows the reconstruction of the RF signal at a frequency of 3.0 MHz. Referring to Figure 22A, waveform 22001a is the reconstructed waveform using Equation (9), and waveform 22003a is the output of a differential oscilloscope probe that measures the signal input to the demodulator. Referring to Figure 22B, waveform 22001b is the reconstructed waveform using Equation (9), and waveform 22003b is the output of a differential oscilloscope probe that measures the signal input to the demodulator. Referring to Figure 22C, waveform 22001c is the reconstructed waveform using Equation (9), and waveform 22003c is the output of a differential oscilloscope probe that measures the signal input to the demodulator. From Figures 22A to 22C, it can be seen that the reconstructed waveforms exactly match the measured waveforms.

[0118] The above-described embodiment regarding the method of multi-bit phase shift used by the power guarantee circuit to reconstruct the RF signal output from the power amplifier 3001 can reduce the requirements regarding the operating frequency of the LO clock requirements. In the conventional method, the operating frequency of the LO clock using the traditional method can operate at a frequency corresponding to the second, third, fourth, fifth, sixth, or other higher harmonic frequencies. In such a conventional method, the clock frequency of the demodulator is set to approximately four times the harmonic frequency at which the LO clock is operating. This setting may increase the complexity, noise, and / or cost of the circuit. The multi-phase shift method described in this specification can be applied to higher-order harmonic frequencies without increasing the operating frequency of the LO clock frequency and / or without giving any other changes to the electronic hardware.

[0119] Correction of the error of the measurement value acquired by the power measurement system In various embodiments, the RF power delivered to the ultrasonic transducer 200 may be different from the RF power output from the power amplifier 3001 that is measured by the power measurement system 3007. The difference between the RF power delivered to the ultrasonic transducer 200 and the RF power measured by the power measurement system 3007 may be due to (i) errors resulting from parasitic reactances on the circuit board of the RFTH module, (ii) errors resulting from parasitic reactances of the current and voltage sensing resistors used in the power measurement system 3007, (iii) deviations from the nominal gain in the IQ demodulators of the power measurement system 3007 and / or the power amplifier 3001, (iv) insertion losses of the transformers used in the power measurement system 3007, (v) undesirable impedance transformation effects of the cables connecting the RFTH module and the ultrasonic transducer, and / or (vi) phase errors between the voltage and current measurements of the IQ demodulator, among one or more of these. FIG. 23A illustrates various causes of errors that can result in a difference between the RF power delivered to the ultrasonic transducer 200 and the RF power measured by the power measurement system 3007. In FIG. 23A, the deviation from the nominal gain of the IQ demodulator and amplifier is shown in block 23001, and the errors resulting from the current sensing resistor and voltage sensing components, as well as the parasitic reactances of the PCB, are shown in blocks 23003 and 23005, and the error resulting from the undesirable cable effect is shown in block 23007. The different causes of error can be modeled by an equivalent two-port network 23009 disposed between the power amplifier 3001 and the ultrasonic transducer 200, as shown in FIG. 23B.

[0120] To reduce the difference between the RF power delivered to the ultrasonic transducer 200 and the RF output power measured by the power measurement system 3007, the power measurement system 3007 can include a self-calibrating two-port network compensation module 24001 as shown in FIG. 24, which captures the different causes of error discussed above that result in a difference between the RF power delivered to the ultrasonic transducer 200 and the RF power measured by the power measurement system 3007.

[0121] To correct various errors, the two-port network parameters of the two-port network compensation module 24001 are obtained using the following approach. An RF signal is delivered to a set of N known load impedances Z L,N within an impedance range that has a magnitude |Z| from 20 Ω to 200 Ω and a phase ∠ from -60° to 60°. The N known load impedances are attached to port 2 of the two-port network, and the power measurement system 3007 is attached to port 1 of the two-port network. The voltage V L,N across each load Z 2,N at port 2 is measured (e.g., using an oscilloscope), and simultaneously, the voltage V 1,N and current I 1,N at port 1 are measured using the power measurement system 3007. A least squares fitting is performed to obtain the two-port network parameters from each value of the voltage V 1,N and current I 1,N measured by the power measurement system at port 1, the voltage V L,N across each load Z 2,N and the corresponding current I 2,N and Z L,N given by the ratio of V 2,N and Z of the N known loads. A series of mathematical operations are performed to determine a set of evaluated complex-valued two-port network parameters that minimize the difference between the measurements obtained by the power measurement system 3007 and the voltages measured across the known impedances.

[0122] When the two-port network parameters are obtained with a set of N known loads over an intended operating impedance range, the resulting two-port network parameter values are robust and predict an impedance that does not exist in the set of N impedances used to obtain the evaluation values. Since the two-port network parameters can be frequency-dependent quantities, their calculation is performed at each frequency at which a correction can be applied. If the measured values of voltage and impedance are sampled densely within a frequency, linear interpolation of the two-port network parameters can be applied to obtain accurate evaluation values at frequencies between the sampled frequencies. For example, measuring at many frequencies from 32 to 256 over an operating frequency range of 1.0 MHz to 12.0 MHz can provide a smooth function suitable for accurate linear interpolation. In various embodiments, the RFTH module can include a calibration EEPROM integrated circuit (IC) that can store the two-port network parameters. Using the stored two-port network parameters, the measured values obtained by the power measurement system 3007 can be corrected to reduce the difference between the RF power delivered to the ultrasonic transducer 200 and the RF power measured by the power measurement system 3007. In various embodiments, the plurality of N calibrated impedances Z L can be four or more.

[0123] Systems and methods for predicting the output power delivered by an ultrasonic transducer In various embodiments, it may be advantageous to predict how much acoustic output can be delivered before the amplifier is switched on. Predicting how much acoustic output can be delivered before the amplifier is switched on can be difficult in systems where the power amplifier is not reserved for use with a particular transducer. For example, in many embodiments of a treatment system, various power amplifiers may be used interchangeably with various transducers. Further, in many embodiments of a treatment system, the transducer may need to be replaced more frequently than the drive subsystem. In such embodiments, a power amplifier can be used to drive various transducers when they are replaced and / or updated.

[0124] Accordingly, some desirable requirements for systems and methods for predicting output power include: (i) predicting the delivered power with an error of less than 0.3 dB; (ii) any transducer can be paired with any power amplifier, and the output delivered by the transducer is within a margin of error of the commanded output; and (iii) the output delivered by the transducer is within a margin of error of the commanded output for a wide range of transducer impedances.

[0125] In various systems and methods for predicting power, individual calibration measurements can be stored with the transducer and also with the power amplifier. Based on the calibration measurements stored in the power amplifier and the ultrasonic transducer, the RF power output by the power amplifier can be selected to output an RF signal at a desired output power that will deliver the desired acoustic energy when provided to the ultrasonic transducer. Two different prediction methods are conceivable for this application. The first method assumes that the variation in the power amplifier output impedance is small. The second method has no such assumption but requires more complex calibration steps.

[0126] Exemplary Method 1 In the first method, the ultrasonic transducer is configured to access a first look-up table (LUT) that stores a correlation between the acoustic output output by the ultrasonic transducer and the power delivered to a 50 Ω load at the same amplitude setting value. The first LUT can be generated during factory calibration of the ultrasonic transducer using a reference power amplifier. The first LUT can be stored within the ultrasonic transducer.

[0127] The power amplifier within the drive subsystem 3000 of the RFTH module can access a second LUT that stores a correlation between the amplitude of the RF signal output from the power amplifier and the power to a 50 Ω load obtained during factory calibration of the power amplifier. The second LUT can be stored in the power amplifier, the drive subsystem 3000, or the RFTH module.

[0128] Exemplary method 2 In the second method, a first look-up table (LUT) that includes a correlation between impedance and the electrical-to-acoustic conversion efficiency is generated during factory calibration of the ultrasonic transducer. The first LUT can be stored within the ultrasonic transducer.

[0129] A second LUT that includes the power amplifier output impedance and Thevenin equivalent source voltage as a function of the amplitude setting value is generated. The second LUT can be stored in the power amplifier, the drive subsystem 3000, or the RFTH module.

[0130] An electronic processing system can be configured to calculate the power to the transducer load impedance that may be required to generate a desired acoustic output. This electronic processing system can further be configured to calculate the amplitude setting value of the power amplifier that will output the power to generate the desired acoustic output.

[0131] Power calibration and assurance system Transducers used for HIFU often exhibit tolerances at their resonant frequencies. For example, the tolerance of the resonant frequency across the majority of manufactured transducers can be ±7%. The transducer resonant frequency can also vary with the aging of the transducer and temperature. To ensure that the transducer is driven at its resonant frequency, the frequency of the drive signal can be swept across a frequency range encompassing the resonant frequency while the reflection power or impedance of the transducer is being measured. Proximity to the center frequency can be determined by finding the frequency that reduces / minimizes the deviation of the impedance phase from zero, reduces / minimizes or increases / maximizes the impedance amplitude, reduces / minimizes the voltage standing wave ratio, reduces / minimizes the reflection power, or minimizes the reflection coefficient. In various embodiments, the frequency sweep range can be set to ±100 KHz near the nominal resonant frequency while monitoring the voltage standing wave ratio at each frequency and selecting the frequency at which the voltage standing wave ratio is lowest or minimized.

[0132] It is beneficial that the transducer impedance seen at a fixed frequency can be dynamically adjusted to compensate for these changes as the resonant frequency can change, for example, due to aging and / or temperature. In some embodiments, power assurance measurements can be used to assume the power delivered to the transducer, compare that power to the desired power, and adjust the driver amplitude or drive frequency to reduce the error between the measured power and the desired power.

[0133] In some embodiments, a power assurance system can be used to measure the load impedance. Using prior knowledge about the impedance of other system components placed between the power assurance system and the transducer, the power assurance measurements can be converted through a two-port network representing the system to determine the impedance to find the transducer. In some embodiments, the transducer impedance obtained in this way can be used to determine the power required to achieve a desired acoustic output from the transducer. In some embodiments, the measured values of the transducer impedance obtained during treatment can be used to adjust the drive amplitude to achieve the desired power delivery to the transducer and thus the desired acoustic output from the transducer.

[0134] The efficacy of HIFU treatment may depend on whether there is an acoustically transparent coupling between the transducer and the tissue being treated. Typically, this coupling can be achieved by using a gel placed between the transducer and the skin. However, if the seating of the transducer in the gel is inadequate or there are air bubbles in the gel, the coupling may be insufficient. Therefore, it is desirable to measure the quality of the coupling before initiating treatment and to monitor the quality of the coupling throughout the procedure. The characteristic of a well-coupled tissue is that the interface between the tissue and the coupling medium produces a slight reflectivity of ultrasonic energy. For example, a well-coupled ultrasonic transducer will reflect less than 5% of the incident power at the tissue, i.e., gel interface.

[0135] In some embodiments, the quality of the bond is monitored during the performance of the treatment by monitoring the level of the reflected ultrasonic energy. To provide axial resolution to the location of the disruption within the bond, the ultrasonic used to observe the reflected energy can, by nature, be non - continuous and can output in pulses. By using a pulse waveform, it is possible to measure the distance from the transducer to the reflective surface. In some embodiments, the treatment transducer can be used in a pulse - echo mode as a sensor to detect the reflection of the bond. In other embodiments, the treatment transducer can be used to excite the bonding material and a secondary transducer can be used to measure the reflected signal. In some embodiments, the reflection from the reference plane of the power delivery path can be used as an amplitude reference and the reflection from the bonding surface can be compared therewith to determine whether the bond is acceptable. In some embodiments, the system can stop the performance of the treatment until the reflected power is lower than an acceptable threshold.

[0136] In some embodiments, a calibrated power assurance system can be used to measure the impedance of a transducer. The measured impedance is fitted to a model of the transducer impedance. In some embodiments, the model of the transducer impedance can be a circuit model similar to, for example, the Butterworth-Van Dyke model. In some embodiments, the model of the transducer impedance can be a transmission line model similar to the Krimholtz, Leedom, and Matthaei (KLM) model. In some embodiments, the model of the transducer impedance can include, as parameters, a fixed capacitance, a coupling coefficient, and a radiation resistance. In some embodiments, changes in the model parameters can indicate changes in the transducer characteristics due to aging. Thus, changes in the model parameters can be used to track the aging or temperature of the transducer over time. In some embodiments, the model parameters can be used as pass / fail criteria. In some embodiments, changes in the model parameters can be used to evaluate the drive power required to obtain a desired acoustic output.

[0137] Overview of additional systems In some embodiments, the console 300 includes a communication system (e.g., wifi, Bluetooth, modem, etc.) for communicating with another party, manufacturer, supplier, service provider, Internet, and / or cloud. In some embodiments, the cart 301 has a power source such as a power connection to a battery and / or one or more cords for connecting the power source and communication means (e.g., Ethernet) to the system 20. In some embodiments, the system 20 includes the cart 301. In some embodiments, the system 20 does not include the cart 301. The hand wand 100 can be coupled to the controller 300 by an interface 130, which can be a wired or wireless interface. The interface 130 can be coupled to the hand wand 100 by a connector 145. The distal end of the interface 130 can be connected to a controller connector on a circuit 345 (not shown). In one embodiment, the interface 130 can transmit controllable power from the controller 300 to the hand wand 100. In one embodiment, the system 20 has a plurality of image processing channels (e.g., 8 channels) for ultra-clear HD (high definition) visualization of subcutaneous structures to improve image processing. In one embodiment, the system 20 has a plurality of treatment channels (e.g., 8 channels) and a precision linear drive motor that doubles treatment accuracy while increasing speed (e.g., 25%, 40%, 50%, 60%, 75%, 100%, or more). These features establish one of the most versatile system platforms in the industry and provide a foundation for unprecedented future possibilities.

[0138] The controller 300 can include the ability to connect to one or more interactive image displays 310, which can include a touch screen monitor and a graphical user interface (GUI) that enables a user to interact with the ultrasonic system 20. In one embodiment, it is a second, smaller and more mobile display that enables a user to more easily position and view the treatment screen. In one embodiment, it is a second display (e.g., on a wall, on a mobile device, on a large screen, on a remote screen) that enables a system user to view the treatment screen. In one embodiment, the graphic display 310 includes a touch screen interface 315 (not shown). In various embodiments, the display 310 sets and displays operating conditions including device operating status, treatment parameters, system messages and prompts, and ultrasonic image processing. In various embodiments, the controller 300 can be configured to include, among other things, for example, a microprocessor including software and input / output devices, systems and devices for controlling electronic and / or mechanical scanning and / or multiplexing of transducers and / or transducer modules, a system for power delivery, a system for monitoring, a system for detecting the spatial position of a probe, and / or a system for a transducer and / or a system for multiplexing transducer modules, and / or a system for processing user input and recording treatment results.

[0139] In one embodiment, the hand wand 100 includes a controller or switch that is actuated by one or more fingers such as 150 and 160. In various embodiments, one or more thermal therapy controllers 160 (e.g., switches, buttons) initiate and / or stop therapy. In various embodiments, one or more image processing controllers 150 (e.g., switches, buttons) initiate and / or stop image processing. In one embodiment, the hand wand 100 can include a removable module 200. In other embodiments, the module 200 may be non-removable. In various embodiments, the module 200 can be mechanically coupled to the hand wand 100 using a latch or coupler 140. In various embodiments, one interface guide 235 or a plurality of interface guides 235 can be used to assist in coupling the module 200 to the hand wand 100. The module 200 can include one or more ultrasonic transducers 280. In some embodiments, the ultrasonic transducer 280 includes one or more ultrasonic elements. The module 200 can include one or more ultrasonic elements. The hand wand 100 can include, for example, an image processing only module, a therapy only module, an image processing and therapy module, etc. In various embodiments, the ultrasonic transducer 280 is movable in one or more directions 290 within the module 200. The transducer 280 is connected to an actuation mechanism 400. In various embodiments, the actuation mechanism includes zero, one, or more bearings, shafts, rods, screws, a lead screw 401, an encoder 402 (e.g., an optical encoder for measuring the position of the transducer 280), a motor 403 (e.g., a stepper motor) to help ensure accurate and repeatable movement of the transducer 280 within the module 200. In various embodiments, the module 200 can include a transducer 280 that can emit energy through an acoustic transmissive member 230.In one embodiment, the control module 300 can be coupled to the hand wand 100 via the interface 130, and the graphic user interface 310 can be configured to control and / or configure the module 200. In one embodiment, the control module 300 can supply power to the hand wand 100. In one embodiment, the hand wand 100 can include a power source. In one embodiment, the switch 150 can be configured to control and / or configure the tissue imaging function, and the switch 160 can be configured to control and / or configure the tissue treatment function. In various embodiments, the delivery of the emission energy 50 at a suitable depth of focus, distribution, timing, and energy level is provided by the module 200 via a controlled operation by the control system 300 of the transducer 280 to achieve a desired therapeutic effect in the thermal coagulation zone 550.

[0140] In one embodiment, the module 200 can be coupled to the hand wand 100. The module 200 can emit and receive energy such as ultrasonic energy. The module 200 can be electronically coupled to the hand wand 100, and such a coupling can include an interface for communicating with the controller 300. In one embodiment, the interface guide 235 can be configured to provide and / or configure electronic communication between the module 200 and the hand wand 100. The module 200 can include various probe and / or transducer configurations. For example, the module 200 can be configured to couple to and / or configure a dual-mode imaging / therapy transducer, a combined or coexisting imaging / therapy transducer, separate therapy and imaging probes, etc. In one embodiment, when the module 200 is inserted into or connected to the hand wand 100, the controller 300 automatically detects it and updates the interactive graphical display 310.

[0141] In some embodiments, an access key 320 (e.g., a secure USB drive, key) is removably connected to the system 20 to enable the system 20 to function. In various embodiments, the access key is programmed to be customer-specific and serves multiple functions including system security, country / region-specific access to treatment guidelines and functions, software upgrades, support log transfers and / or credit transfers and / or storage. In various embodiments, the system 20 has Internet and / or data connectivity. In one embodiment, the connectivity provides a way for data to be transferred between the system 20 provider and the customer. In various embodiments, the data includes credit, software updates, and support logs. The connectivity is divided into different model embodiments based on how the user's console is connected to the Internet. In one embodiment, the disconnected model connection includes a console that is disconnected from the Internet and the customer has no Internet access. Credit transfers and software upgrades are done by shipping the access key (such as a USB drive) to the customer. In one embodiment, the semi-connected model connectivity includes a console that is disconnected from the Internet but the customer has Internet access. Credit transfers, software upgrades, and support log transfers are done by using the customer's personal computer, smartphone, or other computing device in combination with the system access key to transfer data. In one embodiment, the fully connected model connection includes a console that is wirelessly connected to the Internet using wifi, cellular modem, Bluetooth, or other protocols. Credit transfers, software upgrades, and support log transfers are done directly between the console and the cloud. In various embodiments, the system 20 connects to an online portal for streamlined inventory management, on-demand treatment purchases, and business analytics insights to take the customer aesthetic treatment business to the next level.

[0142] Figure 2 is a schematic diagram of an ultrasonic system 20 coupled to an area of interest 10. In various embodiments, tissues below or at the same level as the skin surface, such as the epidermis, dermis, subcutaneous tissue, fascia, and superficial musculoaponeurotic system (“SMAS”), and / or muscle, are treated non-invasively using ultrasonic energy. The tissue may also include blood vessels and / or nerves. The ultrasonic energy is focused and can be applied to a target area including at least one of the epidermis, dermis, hypodermis, fascia, and SMAS, whether in focus or potentially out of focus or misaligned, to achieve a therapeutic effect. In various embodiments, the tissue layer of the target area 10 can be in any part of the subject's body. In one embodiment, the tissue layer is in the area of the subject's head and face. A cross-sectional portion of the tissue of the target area 10 includes a skin surface 501, an epidermal layer 502, a dermal layer 503, a fat layer 505, a superficial musculoaponeurotic system 507 (hereinafter referred to as “SMAS 507”), and a muscle layer 509. The tissue may also include a hypodermis 504 that can include any tissue below the dermal layer 503. The combination of these layers may be collectively known as subcutaneous tissue 510. Also, as shown in FIG. 2, a treatment zone 525 is below the surface 501. In one embodiment, the surface 501 can be the skin surface of the subject 500. Embodiments directed to treating tissue layers can be used as examples herein, but the system can be applied to any tissue in the body. In various embodiments, the system and / or method can be used on tissue (including, but not limited to, muscle, fascia, SMAS, dermis, epidermis, fat, adipocytes, cellulite (which may be referred to as gynoid lipodystrophy (e.g., non-dimpled female lipodystrophy)), collagen, skin, blood vessels in the face, neck, head, arms, legs, or any other location on or in the body (including body cavities)) of one or a combination of these. In various embodiments, reduction of cellulite (e.g., non-dimpled type female gynoid lipodystrophy) is achieved in amounts of 2%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 75%, 80%, 90%, 95%, and any range thereof.

[0143] Referring to the explanatory diagram of FIG. 2, one embodiment of the ultrasonic system 20 includes a hand wand 100, a module 200, and a controller 300. In one embodiment, the module 200 includes a transducer 280. The transducers 280 of various embodiments of the ultrasonic system 20 can be adapted and / or configured to treat tissue at a focal depth, which is the distance between the transducer 280 and the target tissue for treatment. In various embodiments, the focal depth can be fixed for a given transducer 280. In one embodiment, the focal depth is adjustable for a given transducer 280. In one embodiment, the transducer 280 is configured to treat simultaneously at a plurality of depths (e.g., 1.5 mm, 3.0 mm, 4.5 mm, or other depths) under the skin surface.

[0144] As discussed above, module 200 can include a transducer that can emit energy through acoustic transmissive member 230. In one embodiment, transducer 280 can have an offset distance that is the distance between transducer 280 and the surface of acoustic transmissive member 230. In one embodiment, the focal depth of transducer 280 is a fixed distance from the transducer. In one embodiment, transducer 280 can have a fixed offset distance from the transducer to acoustic transmissive member 230. In one embodiment, acoustic transmissive member 230 is configured and / or positioned on module 200 or ultrasonic system 20 to contact skin surface 501. In various embodiments, the focal depth exceeds the offset distance by an amount corresponding to treatment at a target region disposed at a tissue depth below skin surface 501. In various embodiments, when ultrasonic system 20 is positioned in physical contact with skin surface 501, the tissue depth is the distance between acoustic transmissive member 230 and the target region, and is measured as the distance from handwand 100, or a portion of the surface of module 200 that contacts the skin (regardless of the presence or absence of an acoustic coupling gel, medium, etc.), and the depth within the tissue from that skin surface contact point to the target region. In one embodiment, the focal depth can correspond to the sum of the offset distance (measured with respect to the surface of acoustic transmissive member 230 that contacts coupling medium and / or skin 501) and the tissue depth to the target region below skin surface 501. In various embodiments, acoustic transmissive member 230 is not used.

[0145] The coupling component can include various substances, materials, and / or devices to facilitate the coupling of the transducer 280 or the module 200 to the region of interest. For example, the coupling component can include an acoustic coupling system configured and / or constructed for acoustic coupling of ultrasonic energy and signals. An acoustic coupling system having possible connections such as a manifold can be utilized to couple sound to the target area and provide lens focusing filled with a liquid or fluid. The coupling system can facilitate such coupling through the use of one or more coupling media including air, gas, water, liquid, fluid, gel, solid, non-gel, and / or any combination thereof, or any other medium that enables signals to be transmitted between the transducer 280 and the target area. In one embodiment, one or more coupling media are provided inside the transducer. In one embodiment, the fluid-filled module 200 includes one or more coupling media inside the housing. In one embodiment, the fluid-filled module 200 includes one or more coupling media inside a sealed housing separable from the dry portion of the ultrasonic device. In various embodiments, a coupling medium is used to transmit ultrasonic energy between one or more devices and tissue with a coupling efficiency of 100%, 99% or more, 98% or more, 95% or more, 90% or more, 80% or more, 75% or more, 60% or more, 50% or more, 40% or more, 30% or more, 25% or more, 20% or more, 10% or more, and / or 5% or more.

[0146] In various embodiments, the transducer 280 can image process and treat the region of interest at any suitable tissue depth. In one embodiment, the transducer module 280 can provide acoustic output in the range of about 1 W or less, about 1 W to about 100 W, greater than about 100 W, for example, 200 W, 300 W, 400 W, 500 W. In one embodiment, the transducer module 280 can provide acoustic output at a frequency of about 1 MHz or less, about 1 MHz to about 10 MHz (e.g., 3 MHz, 4 MHz, 4.5 MHz, 7 MHz, 10 MHz, and greater than about 10 MHz). In one embodiment, the module 200 has a focal depth for treatment at a tissue depth of about 4.5 mm under the skin surface 501. In one embodiment, the module 200 has a focal depth for treatment at a tissue depth of about 3 mm under the skin surface 501. In one embodiment, the module 200 has a focal depth for treatment at a tissue depth of about 1.5 mm under the skin surface 501. Some non-limiting embodiments of the transducer 280 or the module 200 can be adapted and / or configured to deliver ultrasonic energy at tissue depths of 1.5 mm, 3 mm, 4.5 mm, 6 mm, 7 mm, less than 3 mm, 3 mm to 4.5 mm, 4.5 mm to 6 mm, greater than 4.5 mm, greater than 6 mm, etc., and anywhere in the ranges of 0 to 3 mm, 0 to 4.5 mm, 0 to 6 mm, 0 to 25 mm, 0 to 100 mm, etc., and at any depth therein. In one embodiment, the ultrasonic system 20 is provided with two or more transducer modules 280. For example, the first transducer module can apply treatment at a first tissue depth (e.g., about 4.5 mm), the second transducer module can apply treatment at a second tissue depth (e.g., about 3 mm), and a third tissue depth (e.g., about 1.5 - 2 mm) can apply treatment. In one embodiment, at least some or all of the transducer modules can be configured and / or arranged to apply treatment at substantially the same depth.

[0147] In various embodiments, changing the number of focal positions (e.g., having tissue depth, etc.) for ultrasonic treatment can be advantageous for treating a patient at various tissue depths even when the focal depth of transducer 280 is fixed. This can result in synergistic effects and maximize the clinical outcome of a single treatment session. For example, treatment at multiple depths under a single surface area can increase the overall volume of tissue treatment and promote collagen formation and tightening. Additionally, treatment at different depths affects different types of tissue, thereby producing different clinical effects that improve the overall aesthetic result. For example, surface treatment can make wrinkles less noticeable, and deeper treatment can induce the formation of more collagen growth. Similarly, treatment at various sites at the same depth or different depths can improve the treatment.

[0148] Treatment of a subject at different locations in one session may be advantageous in some embodiments, while sequential treatment over time may be useful in other embodiments. For example, a subject can be treated under the same surface area at one depth at time 1, at a second depth at time 2, and so on. In various embodiments, this time can be on the order of nanoseconds, microseconds, milliseconds, seconds, minutes, hours, days, weeks, months, or other periods. New collagen generated by the first treatment may be more sensitive to subsequent treatments, which may be desired for some indications. Alternatively, treatment at multiple depths under the same surface area in a single session can be advantageous because treatment at one depth can synergistically enhance or complement treatment at another depth (e.g., by enhanced blood flow, growth factor stimulation, hormonal stimulation, etc.). In some embodiments, different transducer modules provide treatment at different depths. In one embodiment, a single transducer module can be adjusted or controlled for various depths. A safety feature that minimizes the risk of selecting an incorrect depth can be used in combination with a single-module system.

[0149] In some embodiments, methods are provided for treating the lower face and the neck region (e.g., the area under the chin). In some embodiments, methods are provided for treating (e.g., softening) the submental sulcus. In other embodiments, methods are provided for treating the eye region (e.g., treating under-eye bags, infraorbital laxity). Improvement of upper eyelid laxity and improvement of fine lines and texture around the eyes are achieved by some embodiments treating at various depths. Optimal clinical effects (e.g., softening, tightening) can be achieved by treating various sites during a single treatment session. In some embodiments, the treatment methods described herein are non-invasive cosmetic procedures. In some embodiments, the method can be used in combination with invasive procedures such as surgical facelifts or liposuction where skin tightening is desired. In various embodiments, the method can be applied to any part of the body.

[0150] In one embodiment, the transducer module 200 enables a treatment sequence at a fixed depth on or under the skin surface. In one embodiment, the transducer module enables a treatment sequence at one, two, or more variable or fixed depths below the dermis layer. In some embodiments, the transducer module includes an operating mechanism configured and / or arranged to direct ultrasonic treatment at a series of individual thermal lesions (hereinafter, "thermal coagulation points" or "TCPs") at a fixed focal depth. In one embodiment, the sequence of consecutive individual TCPs has a treatment interval in the range of about 0.01 mm to about 25 mm (e.g., 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 5 mm, 10 mm, 20 mm, and any range therebetween), and the change in the interval varies by 1 to 50% (e.g., 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, and any range therebetween). For example, the interval can be 1.1 mm or less, 1.5 mm or more, about 1.1 mm to about 1.5 mm, etc. In one embodiment, the individual TCPs are discrete. In one embodiment, the individual TCPs overlap. In one embodiment, the operating mechanism is configured and / or arranged to be programmed to provide a variable interval between the individual TCPs. In one embodiment, dithering can be configured and / or arranged to provide a variable interval between the individual TCPs. In some embodiments, the transducer module includes an operating mechanism configured and / or arranged to direct ultrasonic treatment into the sequence such that the TCPs are formed in a linear or substantially linear sequence separated by a treatment distance. For example, the transducer module can be configured and / or arranged to form TCPs along a first linear sequence and a second linear sequence separated by a treatment distance from the first linear sequence. In one embodiment, the treatment distance between adjacent linear sequences of individual TCPs is in the range of about 0.01 mm to about 25 mm. In one embodiment, the treatment distance between adjacent linear sequences of individual TCPs is in the range of about 0.01 mm to about 50 mm.For example, in one embodiment, the treatment distance can be about 2 mm or less, 3 mm or less, about 2 mm to about 3 mm, etc. In some embodiments, the transducer module can include one or more movement mechanisms 400 adapted and / or configured to direct the ultrasonic treatment in a certain sequence, such that the TCP is formed by a linear or substantially linear sequence of individual thermal lesions separated by the treatment distance from other linear sequences. In one embodiment, the treatment is applied in a first direction 290 (e.g., pushing). In one embodiment, the treatment is applied in a direction opposite to the first direction 290 (e.g., pulling). In one embodiment, the treatment is applied in both the first direction 290 and the direction opposite to the first direction (e.g., pushing and pulling). In one embodiment, the treatment distances separating the linear or substantially linear TCP sequences are the same or substantially the same. In one embodiment, the treatment distances separating the linear or substantially linear TCP sequences are different or substantially different for various adjacent pairs of the linear TCP sequences.

[0151] In one embodiment, a first and a second removable transducer module are provided. In one embodiment, each of the first and second transducer modules is configured and / or adapted for both ultrasonic imaging and ultrasonic treatment. In one embodiment, the transducer module is configured and / or adapted for treatment only. In one embodiment, the imaging transducer can be attached to the handle of a probe or a hand wand. The first and second transducer modules are configured and / or adapted to be removably coupled to the hand wand. The first transducer module is configured and / or adapted to apply ultrasonic treatment to a first layer of tissue, and the second transducer module is configured and / or adapted to apply ultrasonic treatment to a second layer of tissue. The second layer of tissue is at a different depth than the first layer of tissue.

[0152] In various embodiments, delivery of the emitted energy at suitable depths of focus, distributions, timings, and energy levels is provided by module 200 via controlled operation by control system 300 to achieve the desired therapeutic effect of controlled thermal damage and treat at least one of epidermis layer 502, dermis layer 503, fat layer 505, SMAS layer 507, muscle layer 509, and / or subcutaneous tissue 504. In various embodiments, the emitted energy can be focused at a depth corresponding to the depth for treating muscle. In various embodiments, the depth can correspond to any tissue, tissue layer, skin, epidermis, dermis, hypodermis, fat, SMAS, muscle, blood vessel, nerve, or other tissue. During operation, module 200 and / or transducer 280 can also be mechanically and / or electronically scanned along surface 501 to treat the expansion region. Monitoring of the treatment area and surrounding structures is provided before, during, and after delivery of ultrasonic energy 50 to at least one of epidermis layer 502, dermis layer 503, subcutaneous 504, fat layer 505, SMAS layer 507, and / or muscle layer 509, the results can be planned and evaluated, and / or feedback can be provided to controller 300 and the user via graphical interface 310.

[0153] In one embodiment, the ultrasonic system 20 generates ultrasonic energy that is directed towards and focused beneath the surface 501. This controlled and focused ultrasonic energy 50 generates a thermal coagulation point or zone (TCP) 550. In one embodiment, the ultrasonic energy 50 forms voids in the subcutaneous tissue 510. In various embodiments, the emitted energy 50 targets the tissue beneath the surface 501 and at a specific focal depth, cuts, excises, coagulates, micro-excises, manipulates, and / or induces a TCP 550 in the tissue portion 10 beneath the surface 501. In one embodiment, during the treatment sequence, the transducer 280 moves in the direction indicated by the arrow mark 290 at specific time intervals to create a series of treatment zones each receiving the emitted energy 50 for creating one or more TCPs 550. In one embodiment, the TCPs can be spaced perpendicular to the direction of movement of the transducer 280. In some embodiments, the orientation of the spaced TCPs can be set at any angle from 0 to 180 degrees from the arrow 290. In some embodiments, the orientation of the spaced TCPs can be set at any angle from 0 to 180 degrees based on the orientation of the polarization region of the transducer 280.

[0154] In various embodiments, the transducer module can include one or more transducer elements. The transducer elements can include a piezoelectrically active material such as lead zirconate titanate (PZT), or any other piezoelectrically active material such as a piezoelectric ceramic, crystal, plastic, and / or composite material, and may include lithium niobate, lead titanate, barium titanate, and / or lead metaniobate. In various embodiments, in addition to or instead of the piezoelectrically active material, the transducer module can include any other material configured and / or arranged to generate radiation and / or acoustic energy. In various embodiments, the transducer module can be configured and / or arranged to operate at different frequencies and treatment depths. The characteristics of the transducer are the outer diameter ("OD") and the focal length (F LIn one embodiment, the transducer has an OD=19 mm and F L In other embodiments, the OD and F may be adapted and / or configured to have OD and F = 15 mm. L Other suitable values ​​of OD, such as less than about 19 mm, more than about 19 mm, etc., and F, such as less than about 15 mm, more than about 15 mm, etc. L can be used. The transducer module can be adapted and / or configured to apply ultrasonic energy at various target tissue depths. As described above, in some embodiments, the transducer module includes a movement mechanism adapted and / or configured to direct the ultrasonic treatment in a linear or substantially linear sequence of individual TCPs with a treatment interval between the individual TCPs. For example, the treatment interval can be about 1.1 mm, 1.5 mm, etc. In some embodiments, the transducer module can further include a movement mechanism adapted and / or configured to direct the ultrasonic treatment in a sequence such that the TCPs are formed in a linear or substantially linear sequence separated by a treatment interval. For example, the transducer module can be configured and / or configured to form TCPs along a first linear sequence and a second linear sequence separated by a treatment interval of about 2 mm to 3 mm from the first linear sequence. In one embodiment, a user can manually move the transducer module across a surface of the treatment area such that adjacent linear sequences of TCPs are generated. In one embodiment, the motion mechanism can automatically move the transducer module across the surface of the treatment area to create an adjacent linear sequence of TCPs.

[0155] Various embodiments relate to a device or method for controlling energy delivery to a target region (such as tissue). In various embodiments, the various forms of energy may include acoustic waves, ultrasonic waves, light, lasers, radio frequency (RF), microwaves, electromagnetic, radiation, heat, cryogenic, electron beams, photon-based, magnetic, magnetic resonance, and / or other forms of energy. Various embodiments relate to a device or method for splitting an ultrasonic energy beam into a plurality of beams. In various embodiments, the device or method can be used to alter the delivery of ultrasonic energy in any procedure, such as any application including therapeutic ultrasound, diagnostic ultrasound, ultrasonic welding, coupling mechanical waves to an object, and other procedures. Generally, tissue effects are achieved by using therapeutic ultrasound and focusing techniques from an aperture to concentrate the acoustic energy. In some examples, high-intensity focused ultrasound (HIFU) is used for such therapeutic purposes. In one embodiment, the tissue effect generated by applying therapeutic ultrasound at a specific depth may be referred to as the generation of a thermal coagulation point (TCP). In some embodiments, a zone can include a point. In some embodiments, a zone is a line, plane, sphere, ellipsoid, cube, or other one-dimensional, two-dimensional, or three-dimensional shape. The generation of TCP at specific locations where thermal and / or mechanical ablation of tissue can occur non-invasively or remotely. In some embodiments, ultrasonic therapy does not include cavitation and / or shock waves. In some embodiments, ultrasonic therapy includes cavitation and / or shock waves.

[0156] In one embodiment, the TCPs can be created in a linear or substantially linear, curved or substantially curved zone or sequence, and each individual TCP is separated from adjacent TCPs by a treatment interval. In one embodiment, multiple TCP sequences can be generated in the treatment area. For example, the TCPs can be formed along a first sequence, and the second sequence can be separated from the first sequence by a treatment distance. Treatment with therapeutic ultrasound can be performed by generating individual TCP sequences and individual TCPs within the sequences, but it may be desirable to reduce the treatment time and the corresponding risk of pain and / or discomfort experienced by the patient. The treatment time can be reduced by forming multiple TCPs simultaneously, almost simultaneously, or sequentially. In some embodiments, the treatment time can be reduced by 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or more by generating multiple TCPs.

[0157] For example, in some non-limiting embodiments, the power system for the transducer can be configured to focus at a tissue depth anywhere in the range of 0.5 mm, 1.0 mm, 1.5 mm, 2 mm, 3 mm, 4.5 mm, 6 mm, less than 3 mm, 0.5 mm to 5 mm, 1.5 mm to 4.5 mm, greater than 4.5 mm, greater than 6 mm, and 0.1 mm to 3 mm, 0.1 mm to 4.5 mm, 0.1 mm to 25 mm, 0.1 mm to 100 mm, and any depth therein (e.g., 6 mm, 10 mm, 13 mm, 15 mm). In some embodiments, the tissue is treated at a depth beneath the skin surface and the skin surface is not damaged. Instead, the treatment effect achieved at a depth beneath the skin surface results in a desirable cosmetic appearance of the skin surface. In other embodiments, the skin surface is treated with ultrasound (e.g., at a depth of less than 0.5 mm).

[0158] One advantage of the motion mechanism is that it can provide more efficient, accurate, and high-precision use of ultrasonic transducers for image processing and / or treatment purposes. One advantage of this type of motion mechanism is that it is at a fixed distance from the conventional fixed array of transducers fixed in the space within the housing. In one embodiment, the transducer module provides an acoustic output for ultrasonic therapy in the range of about 1 W to about 100 W (e.g., 3 to 30 W, 7 to 30 W, 21 to 33 W) and thermally heats and coagulates tissue at a frequency of about 1 MHz to about 10 MHz. In one embodiment, the transducer module is configured to provide an acoustic output for ultrasonic therapy with a peak or average energy in the range of about 1 W to about 500 W (e.g., 3 to 30 W, 7 to 30 W, 21 to 33 W, 100 W, 220 W, or more) and at a frequency of about 1 MHz to about 12 MHz to thermally heat the tissue to cause coagulation. In some embodiments, instantaneous energy is delivered. In some embodiments, average energy is delivered. In one embodiment, the acoustic output may be in the range of 1 W to about 100 W in the frequency range of about 1 MHz to about 12 MHz (e.g., 1 MHz, 3 MHz, 4 MHz, 4.5 MHz, 7 MHz, 10 MHz, 2 to 12 MHz), or may be in the range of about 10 W to about 50 W in the frequency range of about 3 MHz to about 8 MHz (e.g., 3 MHz, 4 MHz, 4.5 MHz, 7 MHz). In one embodiment, the acoustic output may be in the range of 1 W to about 500 W in the frequency range of about 1 MHz to about 12 MHz (e.g., 1 MHz, 4 MHz, 7 MHz, 10 MHz, 2 to 12 MHz), or may be in the range of about 10 W to about 220 W in the frequency range of about 3 MHz to about 8 MHz, or 3 MHz to 10 MHz. In one embodiment, the acoustic output and frequency are about 40 W at about 4.3 MHz and about 30 W at about 7.5 MHz (e.g., 7.0 MHz, 7.2 MHz, 7.4 MHz, 7.6 MHz, 7.8 MHz, 8.0 MHz).The acoustic energy generated by this acoustic output can be from approximately 0.01 joules ("J") to approximately 10 J (e.g., 0.25 J, 0.45 J, 0.5 J, 1.0 J, 1.05 J, 1.20 J, 1.25 J, 1.50 J, 4 J, 6 J, 8 J, 9 J) or from approximately 2 J to approximately 5 J. The acoustic energy generated by the acoustic output can be from approximately 0.01 J to approximately 60,000 J (e.g., in body shaping via bulk heating, submandibular fat, abdomen and / or flanks, arms, inner thighs, outer thighs, buttocks, abdominal laxity, cellulite), from approximately 10 J or from approximately 2 J to approximately 5 J. In one embodiment, the acoustic energy is in the range of less than approximately 3 J (e.g., 0.25 J, 0.45 J, 0.5 J, 1.0 J, 1.05 J, 1.20 J, 1.25 J, 1.50 J, 2.0 J, 2.5 J). In various embodiments, the treatment power intensity is 10 kW / cm. 2 ~100 kW / cm 2 、15 kW / cm 2 ~70 kW / cm 2 、10 kW / cm 2 ~15 kW / cm 2 、15 kW / cm 2 ~20 kW / cm 2 、17 kW / cm 2 ~40 kW / cm 2 、15 kW / cm 2 ~50 kW / cm 2 、20 kW / cm 2 ~40 kW / cm 2 、15 kW / cm 2 ~35 kW / cm 2 、15 kW / cm 2 ~25 kW / cm 2 、25 kW / cm 2 ~70 kW / cm 2 、および / または40 kW / cm 2 ~80 kW / cm 2 である。

[0159] In some of the embodiments described herein, the procedure is entirely cosmetic and not a medical act. For example, in one embodiment, the methods described herein need not be performed by a doctor and are carried out at a spa or other beauty facility. In some embodiments, the system can be used for non-invasive cosmetic treatment of the skin. In some embodiments, a system and method are provided that use targeted high-precision ultrasound via a thermal pathway using a single ultrasound treatment beam or by splitting the ultrasound treatment beam into two, three, four, or more simultaneous focus zones to perform various treatments and / or image processing procedures. In some embodiments, the ultrasound is used for diagnostic and / or therapeutic purposes in the medical field, which includes, but is not limited to, dermatology.

[0160] In various embodiments, ultrasonic imaging is used to ensure adequate acoustic coupling during the performance of an ultrasonic treatment procedure. In various embodiments, ultrasonic imaging is used to prevent treatment in undesired regions within the body, such as bone or an implant. Unlike light, sound requires a medium for propagation. In one embodiment, an ultrasonic treatment system acoustically couples ultrasonic energy from a transducer to the body through an acoustic window using a gel. In this embodiment, the gel is a medium that mimics the acoustic impedance characteristics of tissue, and thus there is an efficient transfer of energy from the device to the tissue. Unfortunately, in some situations, any air pockets between the transducer and the tissue can prevent proper coupling and thus cause an improper transfer of ultrasonic treatment energy. Ultrasonic imaging checks this coupling. Insufficient coupling may appear as shadows or vertical streaks in the ultrasonic image, or as a completely dark image. Even when there is sufficient coupling, tissues or objects such as bone or a graft can cause various problems because these objects have different acoustic impedance and absorption characteristics than soft tissue (e.g., skin, muscle). For this reason, an object (such as bone or an implant) between the device and the intended treatment focus can cause significant reflections and appearance heating at a shallower depth than intended. An object (such as bone) just beyond the focus can also cause problems because the object reflects ultrasonic waves from the soft tissue and easily absorbs them. The reflected energy can cause a higher temperature rise than intended and inadvertently add to the energy already at the treatment focus. The absorbed energy of bone can cause heating of the bone or discomfort.

[0161] In various embodiments, the present invention improves safety characteristics, improves efficacy performance, provides components for the safety and efficacy of bulk heating devices (such as strip treatment, linear focus treatment zones, cylindrical focus lines, planes and / or solids, etc.), provides qualitative and / or quantitative evaluation of bonding for body shaping, submandibular fat, abdomen and / or flanks, arms, inner thighs, outer thighs, buttocks, relaxation, abdominal relaxation, etc., provides mixing of combined images (plurality) with high-resolution images (plurality), is used to evaluate out-of-plane obstacles outside the focus (e.g., bones, intestinal obstruction, implants), and / or can be used to reduce the need for skills equivalent to those of an ultrasound examiner.

[0162] In some embodiments disclosed herein, a non-invasive ultrasonic system is adapted to be used in achieving one or more of the following beneficial aesthetic and / or cosmetic improvement effects, which include face lifting, eyebrow lifting, jawline lifting, eye treatment (e.g., treating jowls, under-eye laxity), wrinkle reduction, fat reduction (e.g., treating fat and / or cellulite), cellulite (sometimes referred to as gynoid lipodystrophy) treatment (e.g., dimpled or non-dimpled gynoid lipodystrophy in women), décolletage improvement (e.g., upper chest), buttock lifting (e.g., buttock tightening), skin tightening (e.g., treating laxity to cause tightening on the face or body such as on the face, neck, chest, arms, thighs, abdomen, buttocks, etc.), scar reduction, burn treatment, tattoo removal, vein removal, vein reduction, sweat gland treatment, hyperhidrosis treatment, freckle removal, acne treatment, and blemish reduction. In one embodiment, the thermal coagulation zone is directed to subcutaneous tissue such as the superficial musculoaponeurotic system (“SMAS”), and another defocused energy is provided to the surface of the skin. In various embodiments, the ultrasonic system is configured to generate local mechanical movement within the tissue and cells for the purpose of creating either local heating for tissue coagulation, ablation, and / or local heating for mechanical cell membrane disruption. In various embodiments, the ultrasonic system is configured to lift the eyebrows (e.g., the brow). In various embodiments, the ultrasonic system is configured to lift sagging tissues such as submandibular (under the jaw) and neck tissues. In various embodiments, the ultrasonic system is configured to improve the collar line and wrinkles. In various embodiments, the ultrasonic system is configured to reduce fat. In various embodiments, the ultrasonic system is configured to reduce the appearance of cellulite. In various embodiments, tissues even under or on the surface of the skin such as the epidermis, dermis, fascia, muscle, fat, and superficial musculoaponeurotic system (“SMAS”) are non-invasively treated with ultrasonic energy.Ultrasonic energy is focused on one or more treatment points and / or zones, which may be unfocused and / or misaligned, and is applied to a target area including at least one of epidermis, dermis, hypodermis, fascia, muscle, fat, cellulite, and SMAS to achieve cosmetic and / or therapeutic effects. In various embodiments, the system and / or method provides non-invasive skin treatment to tissue by heat treatment, coagulation, ablation and / or tightening. In one embodiment, fat reduction is achieved. In various embodiments, reduction or improvement of cellulite (e.g., dimpled or non-dimpled gynoid lipodystrophy) of one or more features (dimples, nodule formation, "yuzu skin" appearance, etc.) is achieved, for example, by about 10-20%, 20-40%, 40-60%, 60-80%, or higher values (as well as overlapping ranges therein) compared to untreated tissue. In one embodiment, the décolletage is treated. In some embodiments, two, three or more beneficial effects are achieved and can be achieved simultaneously during the same treatment period.

[0163] Various embodiments of the present invention address potential issues raised by the management of ultrasonic therapy. In various embodiments, the time to achieve the formation of TCP for a desired cosmetic and / or therapeutic treatment for a desired clinical approach in the target tissue is reduced. In various embodiments, the target tissue is skin, eyelid, eyelash, eyebrow, crow's feet, wrinkle, eye, nose, mouth (e.g., nasolabial fold, perioral wrinkles), tongue, tooth, gum, ear, brain, heart, lung, rib, abdomen (e.g., in case of abdominal relaxation), stomach, liver, kidney, uterus, chest, vagina, prostate, testis, gland, thyroid, internal organ, hair, muscle, bone, ligament, cartilage, fat, fat lobule, adipose tissue, subcutaneous tissue, graft tissue, graft organ, lymphocyte, tumor, cyst, abscess, or part of a nerve, or any combination thereof, but not limited thereto.

[0164] Various embodiments of the ultrasonic treatment and / or image processing device are described in U.S. application Ser. No. 12 / 996,616, published as U.S. Patent Publication No. 2011-0112405A1 on May 12, 2011, which is the U.S. national stage under 35 U.S.C. § 371 of International Application No. PCT / US2009 / 046475, filed Jun. 5, 2009, and published in English on Dec. 10, 2009, and claims the benefit of priority based on U.S. Provisional Application No. 61 / 059,477, filed Jun. 6, 2008, each of which is hereby incorporated by reference in its entirety. Various embodiments of the ultrasonic treatment and / or image processing device are described in U.S. application Ser. No. 14 / 193,234, published as U.S. Patent Publication No. 2014 / 0257145 on Sep. 11, 2014, which is hereby incorporated by reference in its entirety. Various embodiments of the ultrasonic treatment and / or image processing device are described in International Application PCT / US15 / 25581, published as WO2015 / 160708 on Oct. 22, 2015, together with national stage U.S. application Ser. No. 15 / 302,436, and published as U.S. Patent Publication No. 2017 / 0028227 on Feb. 2, 2017, each of which is hereby incorporated by reference in its entirety. Various embodiments of the ultrasonic treatment and / or image processing device are described in International Application PCT / US17 / 046703, published as WO2018 / 035012 on Feb. 22, 2018, together with national stage U.S. application Ser. No. 15 / 562,384, each of which is hereby incorporated by reference in its entirety.

[0165] Some of the embodiments and examples described herein are illustrative and are not intended to limit the full scope of the devices, systems, and methods of these embodiments. Equivalent changes, modifications, and variations of some embodiments, materials, compositions, and methods are possible within the scope of the embodiments described herein and will result in substantially similar results. Various embodiments described herein, and modifications, equivalents, and alternatives that fall within the spirit and scope of the appended claims are included herein.

[0166] Any method disclosed herein need not be performed in the recited order. The methods disclosed herein include the particular acts taken by a practitioner, and can also include, either expressly or by implication, the instruction of these acts by a third party. For example, an act such as "coupling the transducer module to the ultrasonic probe" includes "instructing the coupling of the transducer module to the ultrasonic probe". The ranges disclosed herein also include any and all overlaps, subranges, disclosed values, and combinations thereof. Words such as "up to", "at least", "greater than", "less than", "between", etc. include the recited numbers. Numbers preceded by terms such as "about" or "approximately" include the recited number. For example, "about 25 mm" includes "25 mm". The headings and titles of this specification are provided for convenience and do not limit the subject matter recited in the claims.

Claims

1. 1. An ultrasound treatment system comprising: an ultrasound probe including an ultrasound treatment transducer adapted to apply ultrasound treatment to tissue; a power system configured to supply power to the ultrasound therapy transducer, the power system including a power amplifier device and a circuit; the power amplifier device includes at least one semiconductor transistor; the at least one semiconductor transistor is a field effect transistor; The ultrasonic treatment system, wherein the field effect transistor is configured to operate at a radio frequency (RF) in the range of 200 kHz to 20 MHz with an efficiency of at least 75%.

2. The system of claim 1 , wherein the semiconductor transistor comprises a III-V compound.

3. The system of claim 1 , wherein the semiconductor transistor comprises gallium nitride (GaN).

4. The power amplifier device comprises: a switch mode amplifier design including said field effect transistor; and a circuit configured to generate digital waveforms for driving a plurality of gates of a field effect transducer to drive a piezoelectric ultrasonic transducer; 2. The system of claim 1, wherein the circuit comprises four transistors configured in an H-bridge configuration.

5. The power amplifier device comprises: a switch mode amplifier design including at least one field effect transistor; and a circuit configured to generate digital waveforms for driving a plurality of gates of a field effect transducer to drive a piezoelectric ultrasonic transducer; a signal for driving said field effect transistor is generated by comparing an output of a sine wave direct digital synthesis circuit with a DC voltage; The output power is in the range of 30W to 100W.

2. The system of claim 1, wherein the circuit comprises four transistors configured in an H-bridge configuration.

6. the semiconductor is gallium nitride, A power amplifier device comprising: a switch mode amplifier design including at least one gallium nitride field effect transistor, each gallium nitride field effect transistor including a plurality of gates; and a circuit configured to generate digital waveforms for driving the gates of the gallium nitride field effect transducer to drive a piezoelectric ultrasonic transducer; a signal for driving said field effect transistor is generated by comparing an output of a sine wave direct digital synthesis circuit with a DC voltage; The output power is in the range of 30W to 100W. the circuit includes four gallium nitride transistors arranged in an H-bridge configuration; a gate drive signal having a variable duty cycle that is used to control the harmonic content and power of the output signal; a power amplifier converter for providing radio frequency output signal power with an efficiency of greater than 75%; The supply voltage to the power amplifier is modulated using a switch mode DC-DC converter which reduces a constant high voltage input to a lower supply voltage; two or more power amplifiers, each configured to drive a single piezoelectric transducer element of the high intensity focused ultrasound transducer; the power amplifier is configured to drive an output at two or more different amplitudes; the power amplifier is configured to drive an output with two or more different phases; Phase and frequency are controlled by a direct digital synthesizer; 10. The system of claim 1, wherein the system is configured to drive a transducer with an impedance in the range of 20 ohms to 120 ohms and a phase angle of +45 degrees to -45 degrees.

7. A power amplifier device comprising: a switch mode amplifier design including at least one semiconductor; 2. The system of claim 1, further comprising: a circuit configured to generate a digital waveform for driving the semiconductor to drive the ultrasound therapy transducer.

8. 2. The system of claim 1, wherein the signal that drives the field effect transistor is generated by comparing the output of a sine wave direct digital synthesis circuit to a DC voltage.

9. 10. The system of claim 1, wherein the output power is in the range of 30W to 100W.

10. 10. The system of claim 1, wherein the output power is in the range of 5W to 50W.

11. 2. The system of claim 1, wherein the circuit comprises four transistors configured in an H-bridge configuration.

12. The system of any one of claims 1 to 3 and 7 to 11, wherein the circuit includes two transistors configured in a half-bridge configuration.

13. A system as claimed in any one of claims 1 to 3 and 7 to 11, wherein the gate drive signal has a variable duty cycle which is used to control the harmonic content and power of the output signal.

14. A system according to any one of claims 1 to 3 and 7 to 11, wherein the power amplifier converter provides power to the radio frequency output signal power with an efficiency of greater than 75%.

15. A system according to any one of claims 1 to 3 and 7 to 11, wherein the supply voltage to the power amplifier is modulated using a switch mode DC-DC converter which reduces a fixed high voltage input to a lower supply voltage.

16. The system of any one of claims 1 to 3 and 7 to 11, comprising two or more power amplifiers, wherein a single power amplifier is configured to drive a single piezoelectric transducer element of a high intensity focused ultrasound transducer.

17. The system of any one of claims 1 to 3 and 7 to 11, wherein the high intensity focused ultrasound transducer is configured to be driven by a separate power amplifier.

18. A system according to any one of claims 1 to 3 and 7 to 11, wherein the power amplifier is configured to drive two or more outputs of different amplitudes.

19. A system according to any one of claims 1 to 3 and 7 to 11, wherein the power amplifier is configured to drive two or more different phase outputs.

20. A system according to any one of claims 1 to 3 and 7 to 11, wherein the amplifier is configured to drive outputs at two or more different frequencies.

21. A system according to any one of claims 1 to 3 and 7 to 11, wherein phase and frequency are controlled by a direct digital synthesizer.

22. 12. A system according to any one of claims 1 to 3 and 7 to 11, configured to drive the transducer with an impedance in the range of 20 ohms to 120 ohms and a phase angle of +45 degrees to -45 degrees.

23. 1. A power amplifier device for driving a high intensity ultrasonic transducer, comprising: a switch mode amplifier design including at least one field effect transistor; and a circuit configured to generate a digital waveform for driving the at least one field effect transistor.

24. 1. A power amplifier device for driving a high intensity ultrasonic transducer, comprising: a switch mode amplifier design including at least one gallium nitride field effect transistor, each gallium nitride field effect transistor including a plurality of gates; and a circuit configured to generate digital waveforms for driving the plurality of gates of the gallium nitride field effect transducer to drive a piezoelectric ultrasonic transducer.

25. The following features: the power amplifier is configured to drive two or more outputs of different amplitudes; 25. The power amplifier device of claim 24 including one or more of: the power amplifier configured to drive two or more different phase outputs.

26. 1. A method for controlling power in an ultrasound system to deliver a desired amount of focused acoustic power by an ultrasound transducer, the method comprising: providing a power control system including circuitry including a control system microprocessor and a control system look-up table (LUT); providing an ultrasound transducer including a transducer controller, a transducer microprocessor, and a transducer LUT; determining, using the transducer microprocessor, from the transducer LUT, an amount of power delivered to a load that is equivalent to a desired amount of acoustic power delivered to tissue by the ultrasound transducer; determining, with the control system microprocessor, from the control system LUT, an amplitude of an electrical signal output from a power amplifier of the power system that would deliver an equivalent amount of power delivered to the load; and setting the determined amplitude of the electrical signal output to at least one parameter of the power system output.

27. 27. The method of configuring a power system of claim 26, wherein the load is 50 ohms.

28. 1. An ultrasound treatment system comprising: an ultrasonic probe including a housing containing a piezoelectrically driven ultrasonic therapeutic transducer adapted to focus acoustic ultrasonic waves at a depth from the housing within a focal zone in tissue; a power system configured to provide power to the ultrasound therapy transducer, the power system including a power amplifier; a power measurement system configured to monitor an electrical output power from an output signal from the power amplifier; The power measurement system comprises: a resistive current sense circuit configured to monitor a current output from the power amplifier; a resistive voltage sense circuit configured to monitor a voltage output from the power amplifier; 11. An ultrasonic treatment system, wherein the power measurement system is configured to monitor electrical output power from the power amplifier over a frequency range spanning at least two octaves of the ultrasonic therapy transducer.

29. 1. A system for measuring radio frequency (RF) current and voltage in a drive circuit of a high intensity focused ultrasound system, comprising: a current sensing resistor in series with the load; a shunt voltage sensing resistor network in parallel with the load; a power output voltage and current monitoring circuit (IQ demodulation circuit) having a local oscillator clock synchronized to the phase and frequency of the signal driving the power amplifier and configured to demodulate the output signal to a carrier frequency lower than the ultrasonic drive frequency.

30. A system according to any one of claims 28 to 29, wherein the measurement system is configured to obtain a number of measurements at different relative phase shifts between the local oscillator and the power amplifier.

31. A system according to any one of claims 28 to 29, wherein the local oscillator clock is generated from an independently controlled direct digital synthesizer.

32. A system according to any one of claims 28 to 29, wherein the number of phase measurements is six.

33. A system according to any one of claims 28 to 29, wherein the measurement system is configured to take a plurality of measurements at a local oscillator frequency.

34. A system using a measurement system according to any one of claims 28 to 29 for modifying a gate drive signal to achieve a desired harmonic content in the output signal.

35. 31. A method for determining the number of measurements of the type described in claim 30 for adequately measuring the harmonics by evaluating several harmonics of the lowest frequency in the passband that exceed a system noise floor.

36. 28. A method for calculating the complex harmonic content of the voltage and current waveforms by forming a linear combination of the measurements of claim 27.

37. 1. A method for calibrating a high intensity ultrasound transducer, comprising: calibrating an acoustic output power delivered by a transducer of a driver configuration corresponding to a power delivered by a driver against one or more reference loads of said driver configuration for which calibration information is stored with said transducer; calibrating the electrical driver configuration for the power delivered to one or more reference loads for which the calibration information is stored with the driver; using the transducer calibration information to determine a power level into one or more reference loads for a desired acoustic power setting, and using the driver calibration information to determine a driver configuration for the desired acoustic output power level into the reference load; and calibrating using a processor of a driver configuration to achieve a desired acoustic output power.

38. 38. The method of claim 37, wherein the transducer calibration information also includes the power delivered to the transducer at each acoustic power level, and the stored power information includes a complex power component or a real power component.

39. 40. The method of claim 38, wherein dynamic measurements of power delivered from the driver are made during insonification of tissue and verified against power stored in the transducer calibration for the desired acoustic output level.

40. the transducer calibration information also includes the power delivered to the transducer at each acoustic power level, the stored power information including a complex power component or a real power component; 38. The method of claim 37, wherein dynamic measurements of power delivered from the driver are made during insonification of tissue and verified against power stored in the transducer calibration for the desired acoustic output level.

41. the transducer calibration information also includes the power delivered to the transducer at each acoustic power level, and the stored power information includes a complex power component or a real power component; a dynamic measurement of power delivered from the driver is made during insonification of tissue and verified against a power stored in the transducer calibration for the desired acoustic output level; the acoustic output power is generated by performing a measurement using a force balance; the transducer calibration is stored as a look-up table on a non-volatile memory chip within the transducer; At least one of the voltage or current measured at the driver is conditioned using a transfer matrix represented by the two-port network between the therapy driver output and the transducer; The calibration information is stored in a look-up table (LUT); 38. The method of claim 37, wherein a target voltage is calculated from the calibration information and a desired acoustic output set at the clinic by interpolating the values ​​in one or more look-up tables.

42. 40. The method of claim 37, wherein the acoustic output power is generated by performing measurements using a force balance.

43. 39. The method of any one of claims 37 and 38, wherein the transducer calibration is stored as a look-up table in a non-volatile memory chip within the transducer.

44. 40. The method of any one of claims 37, 38 and 39, wherein at least one of the voltages or currents measured at the driver is adjusted using a transfer matrix represented by the two-port network between the therapy driver output and the transducer.

45. 39. The method of any one of claims 37 and 38, wherein the calibration information is stored in a look-up table (LUT).

46. 46. ​​The method of claim 45, wherein the target voltage is calculated from the calibration information and a desired acoustic output set at a clinic by interpolating the values ​​in one or more look-up tables.

47. 38. Storage within the transducer calibration information of power thresholds at each acoustic power level that define an acceptable range of electrical drive powers to achieve an acceptable range of acoustic output powers according to claim 37.

48. 47. A system for verifying that dynamically measured power is within the range specified in claim 46, comprising dynamically measuring the power delivered by the driver and comparing the power against the threshold value stored in the transducer.

49. 45. The method of claim 44, wherein the transfer matrix of a handpiece and cable assembly that can be exchanged between a transducer and a driver is stored in a non-volatile memory chip within the handpiece and cable assembly.

50. 1. A method for dynamically adjusting power, comprising: measuring the power delivered from the driver; Comparing the measured power to the desired power as determined from the calibration information of claim 37; and adjusting the driver configuration to reduce an error between the desired power and the measured power.

51. 1. A method for dynamically adjusting power, comprising: measuring the electrical impedance of the load and calculating the transducer impedance based on known impedances of other system components; Calculating the required power from the driver to maintain the same amount of dissipated power across the real transducer impedance; and adjusting the driver configuration to meet the power needed to reduce the error between the desired power and the measured power.

52. A method according to any one of claims 49 to 51, wherein the power is dynamically adjusted whenever a treatment is administered.

53. A method for tuning a high intensity focused ultrasound transducer by sweeping frequencies while measuring the voltage standing wave ratio at a driver and selecting as the operating frequency the frequency that minimizes said voltage standing wave ratio.

54. 1. A method for calibrating a high intensity focused ultrasound transducer, comprising: modeling a driver as a Thevenin equivalent source having a frequency dependent source voltage and source impedance and storing calibration information with said driver including said source voltage and source impedance; Measuring and storing the transducer impedance of calibration information on the transducer; calculating the power that would be delivered to a transducer by the driver using the source voltage and source impedance stored in the driver calibration to the load impedance stored in the transducer calibration, and treating the combined system as a voltage divider network.

55. 1. A method for measuring transducer impedance, comprising: calibrating the driver using one or more known reference impedances; Measuring the transducer impedance at one or more frequencies and one or more amplitudes; - matching the measured transducer to a resonant circuit to calculate transducer parameters such as fixed capacitance, coupling coefficient and radiation resistance; and using said characterization to determine transducer life, pass / fail operation, and required amplitude and phase.

56. 56. The method of claim 55, wherein there is a fixed distance between the transducer and the intended treatment area.

57. 57. The method of claim 56, wherein the treatment beam is temporarily moved to an untreated area to determine the amount of backscatter from the treated area using a differential method.

58. 56. The method of claim 55, wherein the transducer impedance is measured by using a short duration excitation pulse to eliminate backscattering or reflections from tissue or the transducer interface.

59. 1. An ultrasound treatment system comprising: an ultrasound probe including an ultrasound treatment transducer adapted to apply ultrasound treatment to tissue; a power system configured to supply power to the ultrasound therapy transducer, the power system including a power amplifier device and a circuit; The ultrasound treatment system, wherein the power amplifier device includes at least one III-V semiconductor power transistor configured to operate with at least 75% efficiency at radio frequencies (RF) in the range of 200 kHz to 20 MHz.

60. 60. The system of claim 59, wherein the at least one III-V semiconductor power transistor is selected from the group consisting of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and AlGaN.

61. 60. The system of claim 59, wherein the at least one III-V semiconductor power transistor is gallium nitride.

62. 60. The system of claim 59, wherein the at least one III-V semiconductor power transistor is not one of GaN, GaAs, GaSb, InP, InAs, InSb, InGaAs, AlSb, AlGaAs, and AlGaN.

63. A power amplifier device comprising: a switch mode amplifier design including a plurality of III-V semiconductor power transistors; and a circuit configured to generate a digital waveform for driving the plurality of III-V semiconductor power transistors to drive a piezoelectric ultrasonic transducer.

64. 60. The system of claim 59, wherein the signal that drives the power transistor is generated by comparing an output of a sine wave direct digital synthesis circuit to a DC voltage.

65. 60. The system of claim 59, wherein the output power is in the range of 30W to 100W.

66. 60. The system of claim 59, wherein the output power is in the range of 5W to 50W.

67. 67. A system as claimed in any one of claims 59 to 66, wherein the circuit comprises four power transistors arranged in an H-bridge configuration.

68. A system according to any one of claims 59 to 66, wherein a gate drive signal has a variable duty cycle which is used to control the harmonic content and power of the output signal.

69. 67. A system according to any one of claims 59 to 66, wherein the power amplifier converter provides the radio frequency output signal power with an efficiency of greater than 75%.

70. A system according to any one of claims 59 to 66, wherein the supply voltage to the power amplifier is modulated using a switch mode DC-DC converter which reduces a fixed high voltage input to a lower supply voltage.

71. 67. The system of any one of claims 59 to 66, comprising two or more power amplifiers, a single power amplifier configured to drive a single piezoelectric transducer element of a high intensity focused ultrasound transducer.

72. A system according to any one of claims 59 to 66, wherein the power amplifier is configured to drive an output at two or more different amplitudes.

73. A system according to any one of claims 59 to 66, wherein the power amplifier is configured to drive outputs with two or more different phases.

74. A system according to any one of claims 59 to 66, wherein phase and frequency are controlled by a direct digital synthesizer.

75. 67. A system according to any one of claims 59 to 66, configured to drive the transducer with an impedance in the range of 20 ohms to 120 ohms and a phase angle of +45 degrees to -45 degrees.

76. 1. A power amplifier device for driving a high intensity ultrasonic transducer, comprising: a switch mode amplifier design including at least one III-V semiconductor power transistor; and a circuit configured to generate a digital waveform for driving the at least one III-V semiconductor power transistor.

77. 1. A device including a plurality of power amplifiers for driving a high intensity ultrasonic transducer, the plurality of power amplifiers comprising: a switch mode amplifier design including a plurality of III-V semiconductor power transistors; and a circuit configured to generate a digital waveform for driving the plurality of III-V semiconductor power transistors to drive a piezoelectric ultrasonic transducer.

78. 78. The device of claim 77, wherein the group III-V semiconductor power transistor is a gallium nitride field effect transistor.

79. The following features: the power amplifier is configured to drive an output at two or more different amplitudes; 80. A power amplifier device according to claim 77 or 78, including one or more of: the power amplifier configured to drive an output with two or more different phases.

80. 1. A method of controlling power in an ultrasound system for delivering a desired amount of focused acoustic power by an ultrasound transducer, the method comprising: providing a power control system including circuitry including a control system microprocessor and a control system look-up table (LUT); providing an ultrasound transducer including a transducer controller, a transducer microprocessor, and a transducer LUT; determining, using the transducer microprocessor, from the transducer LUT, an amount of power delivered to a load that is equivalent to a desired amount of acoustic power delivered to tissue by the ultrasound transducer; determining, with the control system microprocessor, from the control system LUT, an amplitude of an electrical signal output from a power amplifier of the power system that would deliver the equivalent amount of power delivered to the load; setting the determined amplitude of the electrical signal output to at least one parameter of the power system output; The method wherein the load is in the range of 20 to 120 ohms.

27. The method of configuring a power system of claim 26, wherein the load is 50 ohms.

81. 1. An ultrasound treatment system comprising: an ultrasound probe including a housing containing a piezoelectrically driven ultrasound therapeutic transducer adapted to focus acoustic ultrasound waves at a depth from the housing within a focal zone in tissue; a power system configured to provide power to the ultrasound therapy transducer, the power system including a power amplifier; a power measurement system configured to monitor an electrical output power from an output signal from the power amplifier; The power measurement system comprises: a resistive current sense circuit configured to monitor a current output from the power amplifier; a resistive voltage sense circuit configured to monitor a voltage output from the power amplifier; 11. An ultrasonic treatment system, wherein the power measurement system is configured to monitor electrical output power from the power amplifier over a frequency range spanning at least two octaves of the ultrasonic therapy transducer.

82. 1. A system for measuring radio frequency (RF) current and voltage in a drive circuit of a high intensity focused ultrasound system, comprising: a current sensing resistor in series with the load; a shunt voltage sensing resistor network in parallel with the load; a power output voltage and current monitoring circuit (IQ demodulation circuit) having a local oscillator clock synchronized to the phase and frequency of the signal driving the power amplifier and configured to demodulate the output signal to a carrier frequency lower than the ultrasonic drive frequency.

83. A system according to any one of claims 81 to 82, wherein the measurement system is configured to obtain a plurality of measurements at different relative phase shifts between the local oscillator and the power amplifier.

84. A system according to any one of claims 81 to 82, wherein the local oscillator clock is generated from an independently controlled direct digital synthesizer.

85. A system according to any one of claims 81 to 82, wherein the number of phase measurements is six.

86. A system using a measurement system according to any one of claims 81 to 82 for modifying a gate drive signal to achieve a desired harmonic content in the output signal.

87. 82. A method for determining the number of measurements of the type described in claim 81 for appropriately measuring said harmonics by evaluating several harmonics of the lowest frequency of the passband that exceed the system noise floor.

88. A method for calculating the complex harmonic content of voltage and current waveforms by forming a linear combination of a plurality of measurements according to claims 81-82.

89. 13. An ultrasound treatment system having one or more of the features described in the preceding specification.

90. 13. A power amplifier device for driving a high intensity ultrasonic transducer having one or more of the features described in the preceding specification.

91. 13. A method of controlling power in an ultrasound system having one or more of the features described in the preceding specification.

92. A system for measuring radio frequency (RF) current and voltage of a drive circuit in a high intensity focused ultrasound system having one or more of the features described in the preceding specification.

93. A method for calibrating a high intensity ultrasound transducer having one or more of the features described in the preceding specification.

94. A method for detecting the quality of acoustic coupling of a high intensity focused ultrasound transducer through a skin surface, comprising one or more of the features described in the preceding specification.

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