# Patent

## Title
Systems and methods for monitoring and controlling ultrasound power output and stability

## Abstract

Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from a ultrasound transducer; determining a power level threshold of the ultrasound energy; monitoring a power level of the ultrasound energy over time of the ultrasound energy; communicating a power level to a controller; adjusting the frequency of the ultrasound energy upon a change in the power level; and maintaining the power level threshold of the ultrasound energy.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 61/506,609, entitled “Systems and Methods for Monitoring Ultrasound Power Efficiency,” filed Jul. 11, 2011; and U.S. Provisional Patent Application Ser. No. 61/506,610, entitled “Methods and Systems for Controlling Acoustic Energy Deposition into a Medium,” filed Jul. 11, 2011; all of which are incorporated by reference herein.


BACKGROUND
Temperatures change in a treatment device under operate can affect the stability of the device. Cooling the device may help stability, however, cooling device are bulky and require additional energy to operate. Accordingly, new approaches to monitoring ultrasound energy that is transmitted into a region of interest are needed.
SUMMARY
Various embodiments described herein provide methods and systems for monitoring ultrasound energy. Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from a ultrasound transducer; determining a power level threshold of the ultrasound energy; monitoring a power level of the ultrasound energy over time of the ultrasound energy; communicating a power level to a controller; adjusting the frequency of the ultrasound energy upon a change in the power level; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting the frequency to the specific frequency upon a change in the power level. In some embodiments, the method can comprise changing power provided to a transducer providing the ultrasound energy based on the adjusting the frequency of the ultrasound energy. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from an ultrasound transducer; determining a power level threshold of the ultrasound energy; monitoring a temperature of the ultrasound transducer over time; communicating the temperature to a controller; adjusting the frequency of the ultrasound energy upon a change in the temperature; and maintaining the power level threshold of the ultrasound energy.



DRAWINGS
The present disclosure will become more fully understood from the description and the accompanying drawings, wherein:
FIG. 1 is a cross sectional view illustrating tissue layers and ultrasound energy directed to a portion of the tissue layers, in accordance with various non-limiting embodiments;
FIG. 2 is a graph illustrating ultrasound efficiency at a frequency, in accordance with various non-limiting embodiments;
FIG. 3 is a graph illustrating ultrasound efficiency a frequency, in accordance with various nonlimiting embodiments;
FIG. 4 is a block diagram illustrating a system in accordance with various non-limiting embodiments;
FIG. 5 is a block diagram illustrating a system in accordance with various non-limiting embodiments;
FIG. 6 is a block diagram illustrating a system in accordance with various non-limiting embodiments.
FIG. 7 is a block diagram illustrating a system in accordance with various non-limiting embodiments; and
FIG. 8 is a block diagram illustrating a system in accordance with various non-limiting embodiments.



DESCRIPTION
The following description is merely exemplary in nature and is in no way intended to limit the various embodiments, their application, or uses. As used herein, the phrase “at least one of A, B, and C” should be construed to mean a logical (A or B or C), using a non-exclusive logical “or.” As used herein, the phrase “A, B and/or C” should be construed to mean (A, B, and C) or alternatively (A or B or C), using a non-exclusive logical “or.” It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure.
The drawings described herein are for illustrative purposes only of selected non-limiting embodiments and not all possible implementations, and are not intended to limit the scope of any of the various embodiments disclosed herein or any equivalents thereof. It is understood that the drawings are not drawn to scale. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements.
The various embodiments may be described herein in terms of various functional components and processing steps. It should be appreciated that such components and steps may be realized by any number of hardware components configured to perform the specified functions. For example, various embodiments may employ various medical treatment devices, visual imaging and display devices, input terminals and the like, which may carry out a variety of functions under the control of one or more control systems or other control devices. In addition, the embodiments may be practiced in any number of medical contexts and that the various embodiments relating to a method and system for acoustic energy deposition in tissue, as described herein, are merely indicative of one of the many applications for the invention. For example, the principles, features and methods discussed may be applied to any medical application. Further, various aspects of the various embodiments may be suitably applied to cosmetic applications. Moreover, some of the embodiments may be applied to cosmetic enhancement of skin and/or various soft tissue layers.
Various embodiments provide methods and systems to adjust a temperature of a transducer, in order to maintain maximum efficiency of power applied by the transducer. Some embodiments provide methods and systems to minimize or eliminate temperature saturation of a transducer during the delivery of power to the transducer. In some embodiments, methods and systems can control a temperature of a transducer to maintain a desired frequency of energy transmission at a maximum power.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from a ultrasound transducer; determining a power level threshold of the ultrasound energy; monitoring, a power level of the ultrasound energy over time of the ultrasound energy; communicating a power level to a controller; adjusting the frequency of the ultrasound energy upon a change in the power level; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting the frequency to the specific frequency upon a change in the power level. In some embodiments, the method can comprise changing power provided to a transducer providing the ultrasound energy based on the adjusting the frequency of the ultrasound energy. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from an ultrasound transducer; determining a power level threshold of the ultrasound energy; monitoring a temperature of the ultrasound transducer over time; communicating the temperature to a controller; adjusting the frequency of the ultrasound energy upon a change in the temperature; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can further comprise determining a temperature threshold of the ultrasound transducer and terminating the providing ultrasound energy when the temperature is above the temperature threshold.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting the frequency to the specific frequency upon the change of temperature. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold. In some embodiments, the method can further comprise determining a temperature threshold of the ultrasound transducer and terminating the providing ultrasound energy when a temperature of the ultrasound transducer is above the temperature threshold.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from an ultrasound transducer; determining a voltage threshold of the ultrasound energy; monitoring a voltage of the ultrasound transducer over time communicating the voltage to a controller; adjusting the frequency of the ultrasound energy upon a change in the voltage; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can thither comprise determining a temperature threshold of the ultrasound transducer and terminating the providing ultrasound energy when the temperature of the ultrasound transducer is above the temperature threshold.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting the frequency to the specific frequency upon the change of voltage. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from a ultrasound transducer; determining a voltage threshold of the ultrasound energy; monitoring a voltage of the ultrasound transducer over time; communicating the voltage to a controller; adjusting the frequency of the ultrasound energy upon an change in the voltage; monitoring a power level of the ultrasound energy over time of the ultrasound energy; communicating a power level to a controller; adjusting the frequency of the ultrasound energy upon a change in the power level; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can further comprise determining a temperature threshold of the ultrasound transducer and terminating the providing ultrasound energy when the temperature of the ultrasound transducer is above the temperature threshold.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting the frequency to the specific frequency upon the change of voltage. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from a ultrasound transducer; monitoring a power level of the ultrasound energy over time of the ultrasound energy; communicating a power level to a controller; adjusting the frequency of the ultrasound energy upon a change in the power level; monitoring a temperature of the ultrasound transducer over time; communicating the temperature to a controller; adjusting the frequency of the ultrasound energy upon an change in the temperature; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can further comprise determining a temperature threshold of the ultrasound transducer and terminating the providing ultrasound energy when the temperature of the ultrasound transducer is above the temperature threshold.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting, the frequency to the specific frequency upon the change of voltage. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold.
Some embodiments provide a method of providing ultrasound energy having a stable power output. The method can comprise providing ultrasound energy from a ultrasound transducer; determining a voltage threshold of the ultrasound energy; monitoring a voltage of the ultrasound transducer over time; communicating the voltage to a controller; adjusting the frequency of the ultrasound energy upon an change in the voltage; monitoring a power level of the ultrasound energy over time of the ultrasound energy; communicating a power level to a controller; adjusting the frequency of the ultrasound energy upon a change in the power level; monitoring a temperature of the ultrasound transducer over time; communicating the temperature to a controller; adjusting the frequency of the ultrasound energy upon an change in the temperature; and maintaining the power level threshold of the ultrasound energy.
In some embodiments, the method can further comprise determining a temperature threshold of the ultrasound transducer and terminating the providing ultrasound energy when the temperature of the ultrasound transducer is above the temperature threshold.
In some embodiments, the method can further comprise emitting the ultrasound energy at a specific frequency and correcting the frequency to the specific frequency upon the change of voltage. In some embodiments, the method can comprise terminating the providing the ultrasound energy upon a change of the power level above the power level threshold.
In some embodiments, temperature can be monitored by monitoring changes in time of flight of the ultrasound energy from the transducer. In some embodiments, temperature can be monitored by a piezoelectric sensor that may be a portion of transducer, as described herein. In various embodiments, a controller may use a look up table to change a parameter. In some embodiments, controller can employ hardware, software, or a combination of both to change a parameter such as power, voltage or current.
With reference to FIG. 1, a cross sectional view of tissue layers and ultrasound energy directed to at least one of the tissue layers, according to various embodiments of the present invention, is illustrated. The tissue layers illustrated are skin surface 204, epidermal layer 202, dermis layer 206, fat layer 208, SMAS layer 210, and muscle and connective tissue layer 212. Ultrasound probe 205 transmits ultrasound energy 220 transmitting in ROI 215. In various embodiments, ultrasound probe 205 is capable of transmitting ultrasound energy 220 transmitting at variable depths in ROI 215, such as, for example, the depths described herein. Ultrasound probe 205 is capable of transmitting therapeutic ultrasound energy as a single frequency, variable frequencies, or a plurality of frequencies, such as, for example, within the frequency ranges described herein. Ultrasound probe 205 is capable of transmitting ultrasound energy 220 transmitting for variable time periods or to pulse the transmission over time, such as, for example, those time intervals described herein. Ultrasound probe 205 is capable of providing various energy levels of therapeutic ultrasound energy, such as, for example, the energy levels described herein.
Ultrasound probe 205 may be individual hand-held device, or may be part of a treatment system or part of cosmetic enhancement system. The ultrasound probe 205 can provide both therapeutic ultrasound energy and imaging ultrasound energy. However, ultrasound probe 205 may provide only therapeutic ultrasound energy. Ultrasound probe 205 may comprise a therapeutic transducer and a separate imaging transducer. Ultrasound probe 205 may comprise a transducer or a transducer array capable of both therapeutic and imaging applications. According an alternative embodiment, ultrasound probe 205 is coupled directly to one of the tissue layers, as opposed to skin surface 204 to treat the tissue layer. For example, ultrasound probe 205 can be integrated to or attached to a tool, such as, for example, an arthroscopic tool, laparoscopic tool, or an endoscopic tool that may be inserted into a patient's body with minimal invasiveness.
In various embodiments, the ultrasound energy level is in a range of about 0.1 joules to about 500 joules in order to create an ablative lesion. However, the ultrasound energy 108 level can be in a range of from about 0.1 joules to about 100 joules, or from about 1 joules to about 50 joules, or from about 0.1 joules to about 10 joules, or from about 50 joules to about 100 joules, or from about 100 joules to about 500 joules, or from about 50 joules to about 250 joules.
Further, the amount of time ultrasound energy is applied at these levels varies in the range from approximately 1 millisecond to several minutes. However, a range can be from about 1 millisecond to about 5 minutes, or from about 1 millisecond to about 1 minute, or from about 1 millisecond to about 30 seconds, or from about 1 millisecond to about 10 seconds, or from about 1 millisecond to about 1 second, or from about millisecond to about 0.1 seconds, or about 0.1 seconds to about 10 seconds, or about 0.1 seconds to about 1 second, or from about 1 millisecond to about 200 milliseconds, or from about 1 millisecond to about 0.5 seconds.
The frequency of the ultrasound energy can be in a range from about 0.1 MHz to about 100 MHz, or from about 0.1 MHz to about 50 MHz, or from about 1 MHz to about 50 MHz or about 0.1 MHz to about 30 MHz, or from about 10 MHz to about 30 MHz, or from about 0.1 MHz to about 20 MHz, or from about 1 MHz to about 20 MHz, or from about 20 MHz to about 30 MHz.
The frequency of the ultrasound energy can be in a range from about 1 MHz to about 12 MHz, or from about 5 MHz to about 15 MHz, or from about 2 MHz to about 12 MHz or from about 3 MHz to about 7 MHz.
In some embodiments, the ultrasound energy can be transmitted to depths at or below a skin surface in a range from about 0 mm to about 150 mm, or from about 0 mm to about 100 mm, or from about 0 mm to about 50 mm, or from about 0 mm to about 30 mm, or from about 0 mm to about 20 mm, or from about 0 mm to about 10 mm, or from about 0 mm to about 5 mm. In some embodiments, the ultrasound energy can be transmitted to depths below a skin surface in a range from about 5 mm to about 150 mm, or from about 5 mm to about 100 mm, or from about 5 mm to about 50 mm, or from about 5 mm to about 30 mm, or from about 5 mm to about 20 mm, or from about 5 mm to about 10 mm. In some embodiments, the ultrasound energy can be transmitted to depths below a skin surface in a range from about 10 mm to about 150 mm, or from about 10 mm to about 100 mm, or from about 10 mm to about 50 mm, or from about 10 mm about 30 mm, or from about 10 mm to about 20 mm, or from about 0 mm to about 10 mm.
In some embodiments, the ultrasound energy can be transmitted to depths at or below a skin surface in the range from about 20 mm to about 150 mm, or from about 20 mm to about 100 mm, or from about 20 mm to about 50 mm, or from about 20 mm to about 30 mm. In some embodiments, the ultrasound energy can be transmitted to depths at below a skin surface in a range from about 30 mm to about 150 mm, or from about 30 mm to about 100 mm, or from about 30 mm to about 50 mm. In some embodiments, the ultrasound energy can be transmitted to depths at or below a skin surface in a range from about 50 mm to about 150 mm, or from about 50 mm to about 100 mm. In some embodiments, the ultrasound energy can be transmitted to depths at or below a skin surface in a range from about 20 mm to about 60 mm, or from about 40 mm to about 80 mm, or from about 10 mm to about 40 mm, or from about 5 mm to about 40 mm, or from about 0 mm to about 40 mm, or from about 10 mm to about 30 mm, or from about 5 mm to about 30 mm, or from about 0 mm to about 30 mm.
In various embodiments, a temperature of tissue receiving the ultrasound energy can be in a range from 30° C. to about 100° C., or from 43° C. to about 60° C., or from 50° C. to about 70° C., or from 30° C.; to about 50° C., or from 43° C. to about 100° C., or from 33° C. to about 100° C., or from 30° C. to about 65° C., or from 33° C. to about 70° C., as well as variations thereof.
Also, depending at least in part upon a specific biological effect and the tissue layers that are targeted, temperature of tissue receiving the ultrasound energy within ROI 215 may change in a range from approximately 10° C. to about 15° C. in various embodiments, a temperature of tissue receiving the ultrasound energy is raised to a temperature in a range from about 40° C. to about 55° C., or from about 43° C. to about 48° C., or below a threshold of ablation of the tissue.
Moving to FIG. 2, a graph illustrates efficiency of an ultrasound transducer at specific frequency fc, in accordance with various embodiments. Efficiency of a transducer is defined as the ratio of the power output in the desired form to the total power input. Mathematically, if Pin represents the total power input and Pout represents the power output in the desired form, then the efficiency E, as a ratio between 0 and 1, is given by:

E=Pout/Pin  Equation 1

If E % represents the efficiency as a percentage, then:

E %=100Pout/Pin  Equation 2

In general, a transducer is not 100% efficient and power is typically lost during the operation of the transducer in the form of heat. However, for a high-Q transducer, efficiency can approach 100% and heat generated by the transducer is minimized. A transducer is most efficient at specific frequency fc, as illustrated in FIG. 2. The transducer has the maximum power output at frequency fc.
When a transducer operates, the transducer heats up over time and the temperature of the transducer changes. As the temperature of the transducer changes, the resonant frequency will shift towards frequency ft, as illustrated in FIG. 3. This frequency shift decreases the efficiency of the transducer and, the power output from the transducer is significantly lower in the example of FIG. 3 as compared to the example of FIG. 2.
Transducer efficiency decreases due to changes in temperature of the transducer as a function of time. In addition, a change in temperature of the transducer will cause a frequency shift. The frequency shift changes as a function of increasing temperature of the transducer. A frequency shift decreases efficiency and can cause a system to change total power input to make up for a loss of power applied by the transducer. A frequency shift will change the impedance of the transducer.
In various embodiments, systems and methods, described herein, monitor transducer temperature and report changes in temperature to a controller to modify the frequency generation to the transducer. In various embodiments, systems and methods can monitor transducer temperature and report changes in temperature to a controller to modify the total power input to the transducer. In various embodiments, systems and methods can monitor efficiency and controls transducer temperature to prevent energy transmission from a shift in frequency.
In various embodiments, systems and methods can at least one of monitor transducer temperature and control transducer temperature. In various embodiments, systems and methods can operate the transducer to at or near maximum efficiency of power over a period of time. In various embodiments, systems and methods can operate the transducer to at or near maximum efficiency of power as a temperature of the transducer changes. In various embodiments, systems and methods can modify temperature of the transducer to maintain operation at or near maximum efficiency of power. In various embodiments, systems and methods can prevent a change in impedance of the transducer.
In some embodiments, energy emission, such as, an ultrasound emission, can be directed to targeted tissue to initiate a desired treatment to the targeted tissue. If the power of the energy emission, such as, an ultrasound emission, is too high, the targeted tissue can be permanently damaged, which provide pain to the patient being treated. In addition, if the power of the energy emission such as, an ultrasound emission, is too high, the desired treatment to the targeted tissue may not be effective. If the power of the energy emission, such as, an ultrasound emission, is too low, the desired treatment to the targeted tissue may not be effective.
If the efficiency of the transducer degrades, the power of energy emission decreases. If the temperature of the transducer changes, the efficiency of the transducer changes and the power of energy emission decreases. For the most effective treatment to targeted tissue, power of energy emission is constant. Various embodiments provide methods and systems to provide constant energy emission from transducer 110 that is directed to targeted tissue.
Referring to FIG. 4, system 131 is illustrated, in accordance with some embodiments. System 131 can comprise drivers 102, power sensor 104, transducer 110, controller 115, and oscillator 120. In various embodiments, oscillator 120 generates a frequency which is communicated to drivers 102 to power transducer 110 to produce energy transmission 150 at the frequency. Oscillator 120 can be an oscillator or any frequency generator, now known or later developed. For example, oscillator 120 can be but is not limited to, a function generator, a frequency generator, a waveform generator, a signal generator, pitch generator, a wave generator, or a pulse generator, frequency synthesizer, direct digital synthesizer, or combinations thereof. In some embodiments, oscillator 120 can be combined with or integrated to drivers 102. In some embodiments, oscillator 120 is programmable. In some embodiments, controller 115 can be combined with or integrated to at least one of oscillator 120 and drivers 102. In some embodiments, power sensor 104 can be combined with or integrated to at least one of oscillator 120, controller 115 and drivers 102. In some embodiments, power sensor 104 can be combined with or integrated to at least one of oscillator 120, and drivers 102. In some embodiments, power sensor 104 can be combined with or integrated to at least one of controller 115 and drivers 102. In some embodiments, power sensor 104 can be combined with or integrated to at least one of oscillator 120, and controller 115. In some embodiments, power sensor 104 can be combined with or integrated to drivers 102. In some embodiments, power sensor 104 can be combined with or integrated to oscillator 120. In some embodiments, power sensor 104 can be combined with or integrated to controller 115.
In some embodiments, power sensor 104 monitors power input from drivers 102 to transducer 110. In some embodiments, power sensor 104 communicates with controller 115, which controls oscillator 120. In some embodiments, controller 115 receives signal from power sensor 104 and controls a frequency generated by oscillator 120 based on the received signal. In some embodiments, power sensor 104 communicates a power level of the power input from drivers 102.
As transducer 110 efficiency of energy transmission 150 degrades, for example as illustrated in FIG. 3, drivers 102 changes the power input to transducer 110. In some embodiments, power sensor 104 detects the change in power input to transducer 110 and communicates with controller 115, which controls oscillator 120 to change in the power level of the power input from supply and/or drivers 102. In some embodiments, oscillator 120 generates a correction to the frequency which is communicated to the drivers 102, which is based on the communication from the power sensor 104. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102. In some embodiments, energy transmission 150 is corrected to specific frequency fc as illustrated in FIG. 2. If this correction to specific frequency fc does not lower the power input from the drivers 102 to transducer 110 below a threshold, power sensor 104 communicates this elevated power level to controller 115, which controls oscillator 120 for another generation of a correction to the frequency. In some embodiments, system 131 comprises a shut off power function, which is initiated if power sensor 104 detects a power level that is above a predetermined threshold, in some embodiments, the shut off power function prevents the damaging or destroying of transducer 110.
In some embodiments, the thickness of the transduction element of transducer 110 may be configured to be uniform. That is, the transduction element may be configured to have a thickness that is generally substantially the same throughout. In another exemplary embodiment, the transduction element may also be configured with a variable thickness, and/or as a multiple damped device. For example, the transduction element of transducer 110 may be configured to have a first thickness selected to provide a specific operating frequency of a lower range, for example from approximately 1 kHz to 3 MHz. The transduction element may also be configured with a second thickness selected to provide a specific operating frequency of a higher range, for example from approximately 3 to 100 MHz or other frequency ranges described herein.
In yet another exemplary embodiment, transducer 110 may be configured as a single broadband transducer excited with two or more frequencies to provide an adequate output for raising the temperature within ROI 215 to the desired level. Transducer 110 may also be configured as two or more individual transducers, wherein each transducer 110 may comprise a transduction element. The thickness of the transduction elements may be configured to provide specific-operating frequencies in a desired treatment range. For example, in some embodiments, transducer 110 may comprise a first transducer 110 configured with a first transduction element having a thickness corresponding to a specific frequency range of approximately 1 MHz to 3 MHz, and a second transducer 110 configured with a second transduction element having a thickness corresponding to a specific frequency of approximately 3 MHz to 100 MHz or frequency ranges described herein.
Moreover, in some embodiments, any variety of mechanical lenses or variable focus lenses, e.g. liquid-filled lenses, may also be used to focus and or defocus the energy field. For example, transducer 110 may also be configured with an electronic focusing array in combination with one or more transduction elements to facilitate changed flexibility in treating ROI 215. Array may be configured in a manner similar to transducer 110. That is, array may be configured as an array of electronic apertures that may be operated by a variety of phases via variable electronic time delays. Accordingly, the electronic apertures of array may be manipulated, driven, used, configured to produce and/or deliver energy in a manner corresponding to the phase variation caused by the electronic time delay. For example, these phase variations may be used to deliver defocused beams, planar beams, and/or focused beams, each of which may be used in combination to achieve different physiological effects in ROI 215.
Transduction elements may be configured to be concave, convex, and/or planar. For example, transduction elements can be configured to be concave in order to provide focused energy for treatment of ROI 215. In another exemplary embodiment, transduction elements may be configured to be substantially flat in order to provide substantially uniform energy to ROI 215. In addition, transduction elements may be configured to be any combination of concave, convex, and/or substantially flat structures. For example, a first transduction element may be configured to be concave, while a second transduction element may be configured to be substantially flat.
Moreover, transduction element can be any distance from the skin surface 204. In that regard, it can be far away from the skin surface 204 disposed within a long transducer 110 or it can be just a few millimeters from skin surface 204. In certain exemplary embodiments, positioning the transduction element closer to skin surface 204 is better for transmitting ultrasound at high frequencies. Moreover, both two and three dimensional arrays of transduction elements can be used in various embodiments.
In some embodiments, transducer 110 may also be configured as an annular array to provide planar, focused and/or defocused acoustical energy. For example, in some embodiments, an annular array may comprise a plurality of rings. Rings may be mechanically and electrically isolated into a set of individual elements, and may create planar, focused, or defocused waves. For example, such waves can be specified on-axis, such as by methods of adjusting corresponding phase delays. An electronic focus may be moved along various depth positions in ROI 215, and may enable variable strength or beam tightness, while an electronic defocus may have varying amounts of defocusing. In some embodiments, a lens and/or convex or concave shaped annular array may also be provided to aid focusing or defocusing such that any time differential delays can be reduced. Movement of annular array in one, two or three-dimensions, or along any path, such as through use of probes, motion mechanisms, any conventional robotic arm mechanisms, and the like may be implemented to scan and/or treat a volume or any corresponding space within ROI 215.
In FIG. 5, system 132 is illustrated, in accordance with some embodiments. System 132 can comprise drivers 102, transducer 110, piezoelectric sensor 124, controller 115, and oscillator 120. In some embodiments, piezoelectric sensor 124 can be combined with or integrated to at least one of oscillator 120 and drivers 102. In some embodiments, piezoelectric; sensor 124 can be combined with or integrated into oscillator 1200 in some embodiments, piezoelectric sensor 124 can be combined with into integrated to drivers 102. In various embodiments, oscillator 120 generates a frequency which is communicated to drivers 102 to power transducer 110 to produce energy transmission 150 at the frequency. In some embodiments, piezoelectric sensor 124 monitors heat generated by transducer 110. In some embodiments, piezoelectric sensor 124 is coupled to transducer 110. In some embodiments, piezoelectric sensor 124 is integrated to transducer 110. For example, piezoelectric sensor 124 may be a portion of transducer 110, which that is isolated or insulation from the rest of transducer 110, and may comprise identical materials as transducer 110. However, in one aspect of this example, piezoelectric sensor 124 has the opposite temperature coefficient of transducer (same coefficient but opposite sign) and the piezoelectric sensor 124 changes temperature at the same rate as transducer 110, thus compensating for changes in temperature of transducer 110.
Piezoelectric sensor 124 can comprise ceramic, or any other material or combination of material described herein. In some embodiments, piezoelectric sensor 124 is configured with a temperature coefficient that is lower than the temperature coefficient of transducer 110. In some embodiments, piezoelectric sensor 124 is configured with temperature coefficient, which is negative. In various embodiments, piezoelectric sensor 124 generates an electric potential in response to a temperature change, and communicates this electric potential to controller 115, which controls oscillator 120. In some embodiments, piezoelectric sensor 124 communicates with oscillator 120. In some embodiments, controller 115 receives signal from piezoelectric sensor 124 and controls a frequency generated by oscillator 120 based on the received signal. In some embodiments, piezoelectric sensor 124 communicates the heat generated by transducer 110, which can be communicated using temperature.
As transducer 110 efficiency of energy transmission 150 degrades, for example as illustrated in FIG. 3, heat generated by transducer 110 changes. For example, drivers 102 changes the power input to transducer 110, which can change the heat generated by transducer 110. In some embodiments, piezoelectric sensor 124 detects the change in heat generation by transducer 110 and communicates with controller 115, which controls oscillator 120, the change in heat generation, in some embodiments, oscillator 120 generates a correction to the frequency which is communicated to the drivers 102, which is based on the communication from the piezoelectric device 124. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102, which can lower the amount of heat that is generated by transducer 110. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102. In some embodiments, energy transmission 150 is corrected to specific frequency fc as illustrated in FIG. 2. If this correction to specific frequency fc does not lower the power input from the drivers 102 to transducer 110 below a threshold, piezoelectric sensor 124 communicates this elevated heat generation by transducer 110 to oscillator 124 for another generation of a correction to the frequency. In some embodiments, system 132 comprises a shut off power function, which is initiated if piezoelectric sensor 124 detects a heat generation level or a temperature of transducer 110 is above a predetermined threshold. In some embodiments, the shut off power function prevents the damaging or destroying of transducer 110.
Turning to FIG. 6, system 133 is illustrated, in accordance with some embodiments. System 133 can comprise drivers 102, transducer 110, temperature sensor 127, and oscillator 120. In some embodiments, temperature sensor 127 can be combined with or integrated to at least one of oscillator 120 and drivers 102. In various embodiments, oscillator 120 generates a frequency which is communicated to drivers 102 to power transducer 110 to produce energy transmission 150 at the frequency, in some embodiments, temperature sensor 127 monitors temperature of transducer 110. In some embodiments, temperature sensor 127 coupled to transducer 110, in some embodiments, temperature sensor 127 is integrated to transducer 110. Temperature sensor 127 can be any suitable temperature sensor, now known or later developed. In some embodiments, temperature sensor 127 communicates with controller 115, which communicates with oscillator 120. In some embodiments, temperature sensor 127 communicates with oscillator 120. In some embodiments, controller 115 receives signal from temperature sensor 127 and controls a frequency generated by oscillator 120 based on the received signal. In some embodiments, temperature sensor 127 communicates the temperature of by transducer 110.
As transducer 110 efficiency of energy transmission 150 degrades, for example as illustrated in FIG. 3, heat generated by transducer 110 changes. For example, drivers 102 changes the power input to transducer 110, which can change the heat generated by transducer 110. In some embodiments, temperature sensor 127 detects the change in heat generation by transducer 110 and communicates with controller 115, which controls oscillator 120, the change in heat generation. In some embodiments, oscillator 120 generates a correction to the frequency which is communicated to the drivers 102, which is based on the communication from the piezoelectric device 124. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102, which can lower the amount of heat that is generated by transducer 110. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102. In some embodiments, energy transmission 150 is corrected to specific frequency fc as illustrated in FIG. 2. If this correction to specific frequency fc does not lower the power input from the drivers 102 to transducer 110 below a threshold, temperature sensor 127 communicates this elevated heat generation by transducer 110 to oscillator 124 for another generation of a correction to the frequency. In some embodiments, system 132 comprises a shut off power function, which is initiated if temperature sensor 127 detects a heat generation level or a temperature of transducer 110 is above a predetermined threshold. In some embodiments, the shut off power function prevents the damaging or destroying of transducer 110.
Moving to FIG. 7, system 135 is illustrated, in accordance with some embodiments. System 135 can comprise drivers 102, voltage monitor 105, transducer 110, controller 115, and oscillator 120. In various embodiments, oscillator 120 generates a frequency which is communicated to drivers 102 to power transducer 110 to produce energy transmission 150 at the frequency. Oscillator 120 can be an oscillator or any frequency generator, now known or later developed. For example, oscillator 120 can be but is not limited to, a function generator, a frequency generator, a waveform generator, a signal generator, pitch generator, a wave generator, or a pulse generator, frequency synthesizer, direct digital synthesizer, or combinations thereof. In some embodiments, oscillator 120 can be combined with or integrated to drivers 102. In some embodiments, oscillator 120 is programmable. In some embodiments, controller 115 can be combined with or integrated to at least one of oscillator 120 and drivers 102. In some embodiments, voltage monitor 105 can be combined with or integrated to at least one of oscillator 120, controller 115 and drivers 102. In some embodiments, voltage monitor 105 can be combined with or integrated to at least one of oscillator 120, and drivers 102. In some embodiments, voltage monitor 105 can be combined with or integrated to at least one of controller 115 and drivers 102. In some embodiments, voltage monitor 105 can be combined with or integrated to at least one of oscillator 120, and controller 115. In some embodiments, voltage monitor 105 can be combined with or integrated to drivers 102. In some embodiments, voltage monitor 105 can be combined with or integrated to oscillator 120. In some embodiments, voltage monitor 105 can be combined with or integrated to controller 115. In some embodiments, voltage monitor 105 monitors voltage of power from drivers 102 to transducer 110. In some embodiments, voltage monitor 105 communicates with controller 115, which controls oscillator 120. In some embodiments, controller 115 receives signal from voltage monitor 105 and controls a frequency generated by oscillator 120 based on the received signal, in some embodiments, voltage monitor 105 communicates a voltage level of the voltage of power from drivers 102.
As transducer 110 efficiency of energy transmission 150 degrades, for example as illustrated in FIG. 3, drivers 102 changes the voltage of power to transducer 110. In some embodiments, voltage monitor 105 detects the increase in voltage of power to transducer 110 and communicates with controller 115, which controls oscillator 120 to change in the voltage level of the voltage of power from supply and/or drivers 102. In some embodiments, oscillator 120 generates a correction to the frequency which is communicated to the drivers 102, which is based on the communication from the voltage monitor 105. In some embodiments, the correction to the frequency lowers the voltage level of voltage of power from drivers 102. In some embodiments, energy transmission 150 is corrected to specific frequency fc as illustrated in FIG. 2. If this correction to specific frequency fc does not lower the voltage of power from the drivers 102 to transducer 110 below a threshold, voltage monitor 105 communicates this elevated voltage level to controller 115, which controls oscillator 120 for another generation of a correction to the frequency. In some embodiments, system 135 comprises a shut off power function, which is initiated if voltage monitor 105 detects a voltage level that is above a predetermined threshold. In some embodiments, the shut off power function prevents the damaging or destroying of transducer 110.
FIG. 8 With reference to FIG. 8, system 135 is illustrated, in accordance with some embodiments. System 135 can comprise drivers 102, transducer 110, temperature sensor 127, and oscillator 120. In some embodiments, temperature sensor 127 can be combined with or integrated to at least one of oscillator 120 and drivers 102. In various embodiments, oscillator 120 generates a frequency which is communicated to drivers 102 to power transducer 110 to produce energy transmission 150 at the frequency. In some embodiments, temperature sensor 127 monitors temperature of transducer 110. In some embodiments, temperature sensor 127 coupled to transducer 110. In some embodiments, temperature sensor 127 is integrated to transducer 110. Temperature sensor 127 can be any suitable temperature sensor, now known or later developed. In some embodiments, temperature sensor 127 communicates with controller 115, which communicates with oscillator 120. In some embodiments, temperature sensor 127 communicates with oscillator 120. In some embodiments, controller 115 receives signal from temperature sensor 127 and controls a frequency generated by oscillator 120 based on the received signal. In some embodiments, temperature sensor 127 communicates the temperature of by transducer 110. As transducer 110 efficiency of energy transmission 150 degrades, for example as illustrated in FIG. 3, drivers 102 changes the power to transducer 110, which change the voltage across the transducer 110. In some embodiments, controller 115 detects the change in voltage across transducer 110 and communicates with controller 115. In some embodiments, oscillator 120 generates a correction to the frequency which is communicated to the drivers 102, which is based on the communication from controller 115. In some embodiments, the correction to the frequency lowers the voltage level of voltage across transducer 110, in some embodiments, energy transmission 150 is corrected to specific frequency fc as illustrated in FIG. 2. If this correction to specific frequency fc does not lower the voltage across transducer 110 below a threshold, controller 115 communicates this elevated voltage level to oscillator 120 for another generation of a correction to the frequency.
As transducer 110 efficiency of energy transmission 150 degrades, for example as illustrated in FIG. 3, heat generated by transducer 110 changes. For example, drivers 102 changes the power input to transducer 110 which can change the heat generated by transducer 110. In some embodiments, temperature sensor 127 detects the change in heat generation by transducer 110 and communicates with controller 115, which controls oscillator 120, the change in heat generation. In some embodiments, oscillator 120 generates a correction to the frequency which is communicated to the drivers 102, which is based on the communication from the piezoelectric device 124. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102, which can lower the amount of heat that is generated by transducer 110. In some embodiments, the correction to the frequency lowers the power level of power input from drivers 102. In some embodiments, energy transmission 150 is corrected to specific frequency fc as illustrated in FIG. 2. If this correction to specific frequency fc does not lower the power input from the drivers 102 to transducer 110 below a threshold, temperature sensor 127 communicates this elevated heat generation by transducer 110 to oscillator 124 for another generation of a correction to the frequency. In some embodiments, system 132 comprises a shut off power function, which is initiated if temperature sensor 127 detects a heat generation level or a temperature of transducer 110 is above a predetermined threshold. In some embodiments, the shut off power function prevents the damaging or destroying of transducer 110.
The following patents and patent applications are incorporated by reference: US Patent Application Publication No. 20050256406, entitled “Method and System for Controlled Scanning, Imaging, and/or Therapy” published Nov. 17, 2005; US Patent Application Publication No. 20060058664, entitled “System and Method for Variable Depth Ultrasound Treatment” published Mar. 16, 2006; US Patent Application Publication No. 20060084891, entitled “Method and System for Ultra-High Frequency Ultrasound Treatment” published Apr. 20, 2006; U.S. Pat. No. 7,530,958, entitled “Method and System for Combined Ultrasound Treatment” issued May 12, 2009; US Patent Application Publication No. 2008071255, entitled “Method and System for Treating Muscle, Tendon, Ligament, and Cartilage Tissue” published Mar. 20, 2008; U.S. Pat. No. 6,623,430, entitled “Method and Apparatus for Safely Delivering Medicants to a Region of Tissue Using Imaging, Therapy, and Temperature Monitoring Ultrasonic System,” issued Sep. 23, 2003; U.S. Pat. No. 7,571,336, entitled “Method and System for Enhancing Safety with Medical Peripheral Device by Monitoring if Host Computer is AC Powered” issued Aug. 4, 2009; US Patent Application Publication No. 20080281255, entitled “Methods and Systems for Modulating Medicants Using Acoustic Energy” published Nov. 13, 2008; US Patent Application Publication No. 20060116671, entitled “Method and System for Controlled Thermal Injury of Human Superficial Tissue,” published Jun. 1, 2006; US Patent Application Publication No. 20060111744, entitled “Method and System for Treatment of Sweat Glands,” published May 25, 2006; US Patent Application Publication No. 20080294073, entitled “Method and System for Non-Ablative Acne Treatment and Prevention,” published Oct. 8, 2009; U.S. Pat. No. 8,133,180, entitled “Method and System for Treating Cellulite,” issued Mar. 13, 2012; U.S. Pat. No. 8,066,641, entitled “Method and System for Photoaged Tissue,” issued Nov. 29, 2011; U.S. Pat. No. 7,491,171, entitled “Method and System for Treating. Acne and Sebaceous Glands,” issued Feb. 17, 2009; U.S. Pat. No. 7,615,016, entitled “Method and System for Treating Stretch Marks,” issued Nov. 10, 2009; and U.S. Pat. No. 7,530,356, entitled “Method and System for Noninvasive Mastopexy,” issued May 12, 2009.
It is believed that the disclosure set forth above encompasses at least one distinct invention with independent utility. While the invention has been disclosed herein, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and sub combinations of the various elements, features, functions and/or properties disclosed herein.
Various embodiments and the examples described herein are not intended to be limiting in describing the full scope of systems and methods of this invention. Equivalent changes, modifications and variations of various embodiments, materials, systems, and methods may be made within the scope of the present invention, with substantially similar results.

## Claims

1. A method of providing ultrasound energy having a stable power output, the method comprising:
emitting ultrasound energy from an ultrasound transducer at a specific frequency and at a predetermined power level;
monitoring a power level of the ultrasound energy over a time;
communicating the power level to a controller;
correcting a frequency of the ultrasound energy to the specific frequency upon the power level deviating for the predetermined, power level;
monitoring a temperature of the ultrasound transducer over the time of the emitting ultrasound energy;
communicating the temperature of the ultrasound transducer to the controller; and
correcting the frequency of the ultrasound energy to the specific frequency upon a change in the temperature of the ultrasound transducer, wherein the change of temperature is outside a predetermined temperature range;
thereby maximizing efficiency of the ultrasound transducer emitting the ultrasound energy.

2. The method according to claim 1 further comprising
monitoring a voltage of power driving the ultrasound transducer over time;
communicating the voltage to the controller; and
correcting the frequency to the specific frequency upon a change of voltage of the power driving the ultrasound transducer.

3. The method according to claim further comprising terminating the emitting ultrasound energy upon a change of the power level above a predetermined power level threshold.

4. The method according to claim 1 further comprising terminating the emitting ultrasound energy when the temperature of the ultrasound transducer is above a predetermined temperature threshold.

5. The method according to claim 1 further comprising terminating the emitting ultrasound energy when the temperature of the ultrasound transducer is below a predetermined temperature threshold.

6. The method according to claim 1 further comprising
monitoring the power driving the ultrasound transducer over time;
communicating the voltage to the controller; and
terminating the emitting ultrasound energy when the voltage of the power driving the ultrasound transducer is above a predetermined voltage threshold.

7. The method according to claim 1 further comprising
monitoring a voltage of the power driving the ultrasound transducer over time;
communicating the voltage to the controller; and
terminating the emitting ultrasound energy when the voltage of the power driving the ultrasound transducer is below a predetermined voltage threshold.

8. The method according to claim 1 wherein correcting the ultrasound energy to the specific frequency lowers the temperature of the ultrasound transducer.

9. The method according to claim 1 farther comprising modifying the temperature of the ultrasound transducer to stay within the predetermined temperature range.

10. A method of providing ultrasound energy having a stable power output, the method comprising:
providing ultrasound energy at a center frequency from an ultrasound transducer at a predetermined voltage;
monitoring a voltage level of power driving the ultrasound transducer over time;
communicating the voltage level to a Controller;
correcting the ultrasound energy to the center frequency upon a change in the voltage level of the power driving the ultrasound transducer, as compared to the predetermined voltage;
monitoring a temperature of the ultrasound transducer over time;
communicating the temperature to the controller; and
preventing a shift in the frequency of the ultrasound energy away from the center frequency upon a change in the temperature of the ultrasound transducer over time;
thereby maximizing efficiency of the ultrasound transducer emitting the ultrasound energy.

11. The method according to claim 10 further comprising;
monitoring a power level to the ultrasound transducer over time;
communicating the power level to the controller; and
correcting the ultrasound energy hack to the center frequency upon a change of the power level to the transducer.

12. The method according to claim 10 further comprising terminating the providing ultrasound energy upon a change of the voltage level of the power driving the ultrasound transducer is above a predetermined voltage level threshold.

13. The method according to claim 10, further comprising terminating the emitting ultrasound energy when the voltage level of the power driving the ultrasound transducer is below a predetermined voltage level threshold.

14. The method according to claim 10 further comprising terminating the providing ultrasound energy upon a change of the voltage level of the power driving the ultrasound transducer is below a predetermined voltage level threshold.

15. The method according to claim 10 further comprising terminating the providing ultrasound energy when the temperature of the ultrasound transducer is above a predetermined temperature threshold.

16. The method according to claim 10 further comprising terminating the providing the ultrasound energy when the temperature of the ultrasound transducer is below a predetermined temperature threshold.

17. The method according to claim 10 further comprising terminating the providing the ultrasound energy when the voltage level of the ultrasound transducer is above a predetermined voltage threshold.

18. The method according to claim 10 wherein correcting the ultrasound energy to the center frequency lowers the voltage level of the power driving the ultrasound transducer or lowers the temperature of the ultrasound transducer.

19. The method according to claim 10 further comprising preventing a change in impedance of the ultrasound transducer.