Abstract:
An apparatus for lysing adipose tissue, the apparatus comprising a power source and modulator assembly configured to supply modulated electrical power; an ultrasonic therapeutic transducer connected to said power source and modulator assembly and configured to convert the modulated electrical power to ultrasonic energy directed at a target volume in a region of a body containing adipose and non-adipose tissue, so as to selectively generally lyse the adipose tissue and generally not lyse the non-adipose tissue; an ultrasonic imaging sub-system configured to identify changes in the target volume resulting from the ultrasonic energy; and a lipolysis control computer configured to control said power source and modulator assembly based on the changes identified by said ultrasonic imaging sub-system.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/071,382, filed Feb. 20, 2008, which is a continuation of U.S. patent application Ser. No. 10/021,238, now U.S. Pat. No. 7,347,855, filed Oct. 29, 2001. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to lipolysis generally and more particularly to ultrasonic lipolysis. 
       BACKGROUND OF THE INVENTION 
       [0003]    The following U.S. patents are believed to represent the current state of the art: U.S. Pat. Nos. 4,986,275; 5,143,063; 5,143,073; 5,209,221; 5,301,660; 5,431,621; 5,507,790; 5,526,815; 5,884,631; 6,039,048; 6,071,239; 6,113,558; 6,206,873. 
       SUMMARY OF THE INVENTION 
       [0004]    There is provided, in accordance with an embodiment, an apparatus for lysing adipose tissue, the apparatus comprising: a power source and modulator assembly configured to supply modulated electrical power; an ultrasonic therapeutic transducer connected to said power source and modulator assembly and configured to convert the modulated electrical power to ultrasonic energy directed at a target volume in a region of a body containing adipose and non-adipose tissue, so as to selectively generally lyse the adipose tissue and generally not lyse the non-adipose tissue; an ultrasonic imaging sub-system configured to identify changes in the target volume resulting from the ultrasonic energy; and a lipolysis control computer configured to control said power source and modulator assembly based on the changes identified by said ultrasonic imaging sub-system. 
         [0005]    In some embodiments, said ultrasonic imaging sub-system comprises an ultrasonic imaging transducer and an ultrasonic reflection analyzer. 
         [0006]    In some embodiments, the changes identified by said ultrasonic imaging sub-system comprise cavitation in the target volume. 
         [0007]    In some embodiments, the changes identified by said ultrasonic imaging sub-system comprise lysis of adipose tissue in the target volume. 
         [0008]    In some embodiments, said ultrasonic therapeutic transducer comprises a director configured to vary a focus of the ultrasonic energy directed towards the target volume. 
         [0009]    In some embodiments, the varying of the focus comprises changing a volume of said target volume. 
         [0010]    In some embodiments, the varying of the focus comprises changing a distance of said target volume from said ultrasonic therapeutic transducer. 
         [0011]    There is further provided, in accordance with an embodiment, a method for selectively lysing adipose tissue, the method comprising: generating a time-varying electrical signal having a series of relatively high amplitude portions separated in time by a series of relatively low amplitude portions; converting the electrical signal to a corresponding ultrasonic signal; and directing the ultrasonic signal towards a target volume in a region of a body containing adipose and non-adipose tissue, thereby inducing selective cavitation in the adipose tissue while generally not lysing the non-adipose tissue in the target volume. 
         [0012]    In some embodiments, the series of relatively high amplitude portions comprises: one or more initial portions having amplitude above a cavitation initiation threshold; and later portions having an amplitude above a cavitation maintenance threshold. 
         [0013]    In some embodiments, the series of relatively low amplitude portions comprises portions having amplitude below the cavitation initiation and maintenance thresholds. 
         [0014]    In some embodiments, the series of relatively high amplitude portions comprises between 25-500 relatively high amplitude portions. 
         [0015]    In some embodiments, the generating of the time-varying electrical signal comprises generating the series of the relatively high amplitude portions and the series of relatively low amplitude portions at a duty cycle of between 1:5 and 1:20. 
         [0016]    In some embodiments, the ultrasonic signal has a frequency in the range of 150-1000 KHz. 
         [0017]    There is yet further provided, in accordance with an embodiment, an automatically-positionable adipose tissue lysis apparatus, comprising: an ultrasonic transducer secured to a three-dimensional positioning assembly, said ultrasonic transducer being configured to direct ultrasonic energy at a target volume in a region of a body containing adipose and non-adipose tissue, so as to selectively generally lyse the adipose tissue and generally not lyse the non-adipose tissue; a lipolysis control computer having a video camera connected thereto, said video camera being configured to externally image a portion of the body, and said lipolysis control computer being configured to detect indications on the imaged portion of the body; and a positioning control unit configured to control said three-dimensional positioning assembly so as to automatically position said ultrasonic transducer based on the detected indications. 
         [0018]    In some embodiments, the apparatus further comprises a lipolysis control computer connected to said positioning control unit and configured to control the directing of the ultrasonic energy from said ultrasonic transducer based on the detected indications. 
         [0019]    In some embodiments, the apparatus further comprises an ultrasonic imaging sub-system connected to said lipolysis control computer and configured to identify changes in the target volume resulting from the ultrasonic energy, wherein said lipolysis control computer is further configured to control the directing of the ultrasonic energy from said ultrasonic transducer based on the identified changes. 
         [0020]    In some embodiments, the changes identified by said ultrasonic imaging sub-system comprise cavitation in the target volume. 
         [0021]    In some embodiments, the changes identified by said ultrasonic imaging sub-system comprise lysis of adipose tissue in the target volume. 
         [0022]    In some embodiments, the apparatus further comprises an ultrasonic imaging sub-system connected to said lipolysis control computer and configured to detect thicknesses of tissue layers in the region of the body, wherein said lipolysis control computer is further configured to control the directing of the ultrasonic energy from said ultrasonic transducer based on the detected thicknesses. 
         [0023]    In some embodiments, said lipolysis control computer is further configured to control a focus of said ultrasonic transducer, so as to vary a distance of said target volume from said ultrasonic transducer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
           [0025]      FIG. 1  is a simplified pictorial illustration of the general structure and operation of ultrasonic lipolysis apparatus constructed and operative in accordance with a preferred embodiment of the present invention; 
           [0026]      FIG. 2  is a simplified block diagram illustration of a preferred power source and modulator showing a pattern of variation of ultrasonic pressure over time in accordance with a preferred embodiment of the present invention; 
           [0027]      FIGS. 3A and 3B  are simplified pictorial illustrations of the appearance of an operator interface display during normal operation and faulty operation respectively; 
           [0028]      FIG. 4  is a simplified block diagram illustration of an ultrasonic lipolysis system constructed and operative in accordance with a preferred embodiment of the present invention; and 
           [0029]      FIGS. 5A ,  5 B and  5 C are together a simplified flowchart illustrating operator steps in carrying out lipolysis in accordance with a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Reference is now made to  FIG. 1 , which is a simplified pictorial illustration of the general structure and operation of ultrasonic lipolysis apparatus constructed and operative in accordance with a preferred embodiment of the present invention. As seen in  FIG. 1 , an ultrasonic energy generator and director, such as an ultrasonic transducer  10 , disposed outside a body, generates ultrasonic energy which, by suitable placement of the transducer  10  relative to the body, is directed to a target volume  12  inside the body and is operative to selectively generally lyse adipose tissue and generally not lyse non-adipose tissue in the target volume. 
         [0031]    A preferred embodiment of ultrasonic energy generator and director useful in the present invention comprises an ultrasonic therapeutic transducer  13  including a curved phased array  14  of piezoelectric elements  15 , typically defining a portion of a sphere or of a cylinder, and having conductive coatings  16  on opposite surfaces thereof. The piezoelectric elements  15  may be of any suitable configuration, shape and distribution. An intermediate element  18 , formed of a material, such as polyurethane, which has acoustic impedance similar to that of soft mammalian tissue, generally fills the curvature defined by phased array  14  and defines a contact surface  20  for engagement with the body, typically via a suitable coupling gel (not shown). Contact surface  20  may be planar, but need not be. 
         [0032]    Suitably modulated AC electrical power is supplied by conductors  22  to conductive coatings  16  to cause the piezoelectric elements  15  to provide a desired focused acoustic energy output. 
         [0033]    In accordance with a preferred embodiment of the present invention an imaging ultrasonic transducer subassembly  23  is incorporated within transducer  10  and typically comprises a piezoelectric element  24  having conductive surfaces  26  associated with opposite surfaces thereof. Suitably modulated AC electrical power is supplied by conductors  32  to conductive surfaces  26  in order to cause the piezoelectric element  24  to provide an acoustic energy output. Conductors  32 , coupled to surfaces  26 , also provide an imaging output from imaging ultrasonic transducer subassembly  23 . 
         [0034]    It is appreciated that any suitable commercially available ultrasonic transducer may be employed or alternatively, imaging ultrasonic transducer subassembly  23  may be eliminated. 
         [0035]    It is further appreciated that various types of ultrasonic transducers  10  may be employed. For example, such transducers may include multiple piezoelectric elements, multilayered piezoelectric elements and piezoelectric elements of various shapes and sizes arranged in a phase array. 
         [0036]    In a preferred embodiment of the present invention shown in  FIG. 1 , the ultrasonic energy generator and director are combined in transducer  10 . Alternatively, the functions of generating ultrasonic energy and focusing such energy may be provided by distinct devices. 
         [0037]    In accordance with a preferred embodiment of the present invention, a skin temperature sensor  34 , such as an infrared sensor, may be mounted alongside imaging ultrasonic transducer subassembly  23 . Further in accordance with a preferred embodiment of the present invention a transducer temperature sensor  36 , such as a thermocouple, may also be mounted alongside imaging ultrasonic transducer subassembly  23 . 
         [0038]    Ultrasonic transducer  10  preferably receives suitably modulated electrical power from a power source and modulator assembly  40 , forming part of a control subsystem  42 . Control subsystem  42  also typically includes a lipolysis control computer  44 , having associated therewith a camera  46 , such as a video camera, and a display  48 . A preferred embodiment of power source and modulator assembly  40  is illustrated in  FIG. 2  and described hereinbelow. Ultrasonic transducer  10  is preferably positioned automatically or semi-automatically as by an X-Y-Z positioning assembly  49 . Alternatively, ultrasonic transducer  10  may be positioned at desired positions by an operator. 
         [0039]    In accordance with a preferred embodiment of the present invention, camera  46  is operative for imaging a portion of the body on which lipolysis is to be performed. A picture of the portion of the patient&#39;s body viewed by the camera is preferably displayed in real time on display  48 . 
         [0040]    An operator may designate the outline of a region containing adipose tissue. In accordance with one embodiment of the present invention, designation of this region is effected by an operator marking the skin of a patient with an outline  50 , which outline is imaged by camera  46  and displayed by display  48  and is also employed by the lipolysis control computer  44  for controlling the application of ultrasonic energy to locations within the region. A computer calculated representation of the outline may also be displayed on display  48 , as designated by reference numeral  52 . Alternatively, the operator may make a virtual marking on the skin, such as by using a digitizer (not shown), which also may provide computer calculated outline representation  52  on display  48 . 
         [0041]    In addition to the outline representation  52 , the functionality of the system of the present invention preferably also employs a plurality of markers  54  which are typically located outside the region containing adipose tissue, but may be located inside the region designated by outline  50 . Markers  54  are visually sensible markers, which are clearly seen by camera  46 , captured by camera  46  and displayed on display  48 . Markers  54  may be natural anatomic markers, such as distinct portions of the body or alternatively artificial markers such as colored stickers. These markers are preferably employed to assist the system in dealing with deformation of the region nominally defined by outline  50  due to movement and reorientation of the body. Preferably, the transducer  10  also bears a visible marker  56  which is also captured by camera  46  and displayed on display  48 . 
         [0042]    Markers  54  and  56  are typically processed by computer  44  and may be displayed on display  48  as respective computed marker representations  58  and  60  on display  48 . 
         [0043]      FIG. 1  illustrates the transducer  10  being positioned on the body over a location within the region containing adipose tissue. Blocks designated by reference numerals  62  and  64  show typical portions of a region containing adipose tissue, respectively before and after lipolysis in accordance with a preferred embodiment of the invention. It is seen from a comparison of blocks  62  and  64  that, in accordance with a preferred embodiment of the present invention, within the region containing adipose tissue, the adipose tissue, designated by reference numeral  66 , is lysed, while non-adipose tissue, such as connective tissue, designated by reference numeral  68 , is not lysed. 
         [0044]    Reference is now  FIG. 2 , which is a simplified block diagram illustration of a preferred power source and modulator assembly  40  ( FIG. 1 ), showing a pattern of variation of ultrasonic pressure over time in accordance with a preferred embodiment of the present invention. As seen in  FIG. 2 , the power source and modulator assembly  40  preferably comprises a signal generator  100  which provides a time varying signal which is modulated so as to have a series of relatively high amplitude portions  102  separated in time by a series of typically relatively low amplitude portions  104 . Each relatively high amplitude portion  102  preferably corresponds to a cavitation period and preferably has a decreasing amplitude over time. 
         [0045]    Preferably the relationship between the time durations of portions  102  and portions  104  is such as to provide a duty cycle between 1:2 and 1:250, more preferably between 1:5 and 1:30 and most preferably between 1:10 and 1:20. 
         [0046]    Preferably, the output of signal generator  100  has a frequency in a range of 50 KHz-1000 KHz, more preferably between 100 KHz-500 KHz and most preferably between 150 KHz-300 KHz. 
         [0047]    The output of signal generator  100  is preferably provided to a suitable power amplifier  106 , which outputs via impedance matching circuitry  108  to an input of ultrasonic transducer  10   
         [0048]    ( FIG. 1 ), which converts the electrical signal received thereby to a corresponding ultrasonic energy output. As seen in  FIG. 2 , the ultrasonic energy output comprises a time varying signal which is modulated correspondingly to the output of signal generator  100  so as to having a series of relatively high amplitude portions  112 , corresponding to portions  102 , separated in time by a series of typically relatively low amplitude portions  114 , corresponding to portions  104 . 
         [0049]    Each relatively high amplitude portion  102  preferably corresponds to a cavitation period and has an amplitude at a target volume  12  ( FIG. 1 ) in the body which exceeds a cavitation maintaining threshold  120  and preferably has a decreasing amplitude over time. At least an initial pulse of each relatively high amplitude portion  112  has an amplitude at the target volume  12 , which also exceeds a cavitation initiation threshold  122 . 
         [0050]    Relatively low amplitude portions  114  have an amplitude which lies below both thresholds  120  and  122 . 
         [0051]    Preferably the relationship between the time durations of portions  112  and portions  114  is such as to provide a duty cycle between 1:2 and 1:250, more preferably between 1:5 and 1:30 and most preferably between 1:10 and 1:20. 
         [0052]    Preferably, the ultrasonic energy output of ultrasonic transducer  10  has a frequency in a range of 50 KHz-1000 KHz, more preferably between 100 KHz-500 KHz and most preferably between 150 KHz-300 KHz. 
         [0053]    Preferably, each high amplitude portion  112  is comprised of between 2 and 1000 sequential cycles at an amplitude above the cavitation maintaining threshold  120 , more preferably between 25 and 500 sequential cycles at an amplitude above the cavitation maintaining threshold  120  and most preferably between 100 and 300 sequential cycles at an amplitude above the cavitation maintaining threshold  120 . 
         [0054]    Reference is now made to  FIGS. 3A and 3B , which are simplified pictorial illustrations of the appearance of an operator interface display during normal operation and faulty operation respectively. As seen in  FIG. 3A , during normal operation, display  48  typically shows a plurality of target volumes  12  ( FIG. 1 ) within a calculated target region  200 , typically delimited by outline representation  52  ( FIG. 1 ). Additionally, display  48  preferably provides one or more pre-programmed performance messages  202  and status messages  203 . 
         [0055]    It is seen the various target volumes  12  are shown with different shading in order to indicate their treatment status. For example, unshaded target volumes, here designated by reference numerals  204  have already experienced lipolysis. A blackened target volume  12 , designated by reference numeral  205  is the target volume next in line for lipolysis. A partially shaded target volume  206  typically represents a target volume which has been insufficiently treated to achieve complete lipolysis, typically due to an insufficient treatment duration. 
         [0056]    Other types of target volumes, such as those not to be treated due to insufficient presence of adipose tissue therein or for other reasons, may be designated by suitable colors or other designations, and are here indicated by reference numerals  208  and  210 . 
         [0057]    Typical performance messages  202  may include “CAVITATION IN PROCESS” and “FAT LYSED IN THIS VOLUME”. Typical status messages  203  may include an indication of the power level, the operating frequency, the number of target volumes  12  within the calculated target region  200  and the number of target volumes  12  which remain to undergo lipolysis. 
         [0058]    Display  48  also preferably includes an graphical cross sectional indication  212  derived from an ultrasonic image preferably provided by imaging ultrasonic transducer subassembly  23  ( FIG. 1 ). Indication  212  preferably indicates various tissues in the body in cross section and shows the target volumes  12  in relation thereto. In accordance with a preferred embodiment of the present invention, indication  212  may also provide a visually sensible indication of cavitation within the target volume  12 . 
         [0059]    Turning to  FIG. 3B , it is seen that during abnormal operation, display  48  provides pre-programmed warning messages  214 . 
         [0060]    Typical warning messages may include “BAD ACOUSTIC CONTACT”, “TEMPERATURE TOO HIGH”. The “TEMPERATURE TOO HIGH” message typically relates to the skin tissue, although it may alternatively or additionally relate to other tissue inside or outside of the target volume or in transducer  10  ( FIG. 1 ). 
         [0061]    Reference is now made to  FIG. 4 , which illustrates an ultrasonic lipolysis system constructed and operative in accordance with a preferred embodiment of the present invention. As described hereinabove with reference to  FIG. 1  and as seen in  FIG. 4 , the ultrasonic lipolysis system comprises a lipolysis control computer  44  which outputs to a display  48 . Lipolysis control computer  44  preferably receives inputs from video camera  46  ( FIG. 1 ) and from a temperature measurement unit  300 , which receives temperature threshold settings as well as inputs from skin temperature sensor  34  ( FIG. 1 ) and transducer temperature sensor  36  ( FIG. 1 ). Temperature measurement unit  300  preferably compares the outputs of both sensors  34  and  36  with appropriate threshold settings and provides an indication to lipolysis control computer  44  of exceedance of either threshold. 
         [0062]    Lipolysis control computer  44  also preferably receives an input from an acoustic contact monitoring unit  302 , which in turn preferably receives an input from a transducer electrical properties measurement unit  304 . Transducer electrical properties measurement unit  304  preferably monitors the output of power source and modulator assembly  40  ( FIG. 1 ) to ultrasonic therapeutic transducer  13 . 
         [0063]    An output of transducer electrical properties measurement unit  304  is preferably also supplied to a power meter  306 , which provides an output to the lipolysis control computer  44  and a feedback output to power source and modulator assembly  40 . 
         [0064]    Lipolysis control computer  44  also preferably receives inputs from cavitation detection functionality  308 , tissue layer identification functionality  310  and lysed adipose tissue identification functionality  312 , all of which receive inputs from ultrasonic reflection analysis functionality  314 . Ultrasonic reflection analysis functionality  314  receives ultrasonic imaging inputs from an ultrasonic imaging subsystem  316 , which operates ultrasonic imaging transducer  23  ( FIG. 1 ). 
         [0065]    Lipolysis control computer  44  provides outputs to power source and modulator assembly  40 , for operating ultrasonic therapeutic transducer  13 , and to ultrasonic imaging subsystem  316 , for operating ultrasonic imaging transducer  23 . A positioning control unit  318  also receives an output from lipolysis control computer  44  for driving X-Y-Z positioning assembly  49  ( FIG. 1 ) in order to correctly position transducer  10 , which includes ultrasonic therapeutic transducer  13  and ultrasonic imaging transducer  23 . 
         [0066]    Reference is now made to  FIGS. 5A ,  5 B and  5 C, which are together a simplified flowchart illustrating operator steps in carrying out lipolysis in accordance with a preferred embodiment of the present invention. As seen in  FIG. 4A , initially an operator preferably draws an outline  50  ( FIG. 1 ) on a patient&#39;s body. Preferably, the operator also adheres stereotactic markers  54  ( FIG. 1 ) to the patient&#39;s body and places transducer  10 , bearing marker  56 , at a desired location within outline  50 . 
         [0067]    Camera  46  ( FIG. 1 ) captures outline  50  and markers  54  and  56 . Preferably, outline  50  and markers  54  and  56  are displayed on display  48  in real time. The output of camera  46  is also preferably supplied to a memory associated with lipolysis control computer  44  ( FIG. 1 ). 
         [0068]    A computerized tracking functionality preferably embodied in lipolysis control computer  44  preferably employs the output of camera  46  for computing outline representation  52 , which may be displayed for the operator on display  48 . The computerized tracking functionality also preferably computes coordinates of target volumes for lipolysis treatment, as well as adding up the total volume of tissue sought to undergo lipolysis. 
         [0069]    Preferably, the operator confirms the locations of markers  54  and  56  on display  48  and the computerized tracking functionality calculates corresponding marker representations  58  and  60 . 
         [0070]    In accordance with a preferred embodiment of the present invention the computerized tracking functionality employs markers  54  and marker representations  58  for continuously maintaining registration of outline  50  with respect to outline representation  52 , and thus of target volumes  12  with respect to the patient&#39;s body, notwithstanding movements of the patients body during treatment, such as due to breathing or any other movements, such as the patient leaving and returning to the treatment location. 
         [0071]    The computerized tracking functionality selects an initial target volume to be treated and positioning control unit  318  ( FIG. 4 ), computes the required repositioning of transducer  10 . X-Y-Z positioning assembly  49  repositions transducer  10  to overlie the selected target volume. 
         [0072]    Referring additionally to  FIG. 5B , it is seen that following repositioning of transducer  10 , the lipolysis control computer  44  confirms accurate positioning of transducer  10  with respect to the selected target volume. The ultrasonic imaging subsystem  316  ( FIG. 4 ) operates ultrasonic imaging transducer  23 , causing it to provide an ultrasonic reflection analysis functionality  314  for analysis. 
         [0073]    Based on an output from ultrasonic reflection analysis functionality  314 , the thicknesses of the various tissue layers of the patient are determined. Upon receiving an indication of the tissue layer thicknesses, an operator may approve the selected target volume and activates the power source and modulator assembly  40  ( FIG. 1 ). 
         [0074]    Turning additionally to  FIG. 5C , it is seen that the following functionalities take place: 
         [0075]    Transducer electrical properties measurement unit  304  provides an output to acoustic contact monitoring unit  302 , which determines whether sufficient acoustic contact with the patient is present, preferably by analyzing the current and voltage at therapeutic transducer  13 . 
         [0076]    Transducer electrical properties measurement unit  304  provides an output to power meter  306 , which computes the average electrical power received by the therapeutic transducer  13 . If the average electrical power received by the therapeutic transducer  13  exceeds a predetermined threshold, operation of the power source and modulator assembly  40  may be automatically terminated. 
         [0077]    Skin temperature sensor  34  measures the current temperature of the skin at transducer  10  and supplies it to temperature measurement unit  300 , which compares the skin temperature to the threshold temperature. Similarly, transducer temperature sensor  36  measures the current temperature at transducer  10  and supplies it to temperature measurement unit  300 , which compares the transducer temperature to the threshold temperature. The outputs of temperature measurement unit  300  are supplied to lipolysis control computer  44 . 
         [0078]    The ultrasonic imaging subsystem  316  operates ultrasonic imaging transducer  23  and receives an imaging output, which is analyzed by ultrasonic reflection analysis functionality  314 . The result of this analysis is employed for cavitation detection and a cavitation detection output is supplied to lipolysis control computer  44 . 
         [0079]    Should any of the following four conditions occur, the power source and modulator assembly  40  automatically terminates operation of therapeutic transducer  13 . Should none of the following conditions occur, the automatic operation of power source and modulator assembly  40  continues: 
         [0080]    1. Acoustic contact is insufficient. 
         [0081]    2. Skin temperature exceeds threshold temperature level. 
         [0082]    3. Transducer  13  temperature exceeds threshold temperature level. 
         [0083]    4. Cavitation is not detected. 
         [0084]    Returning to  FIG. 5B , it is noted that during automatic operation of power source and modulator assembly  40 , video camera  46  preferably records the target region and notes whether the transducer  10  remained stationary during the entire treatment duration of the selected target volume  12 . If so, and if none of the aforesaid four conditions took place, lipolysis control computer  44  confirms that the selected target volume was treated. The computerized tracking functionality of lipolysis control computer  44  then proposes a further target volume  12  to be treated. 
         [0085]    If, however, the transducer  10  did not remain stationary for a sufficient duration, the selected target volume is designated by lipolysis control computer  44  as having been insufficiently treated. 
         [0086]    It is appreciated that by using multiple transducers multiplicity of target volumes can be treated at various time patterns such as sequential time patterns or partially overlapping time patterns. 
         [0087]    It is also appreciated that the multiplicity of target volumes may also overlap in space or partially overlap in space. 
         [0088]    The computational tracking functionality is set forth in the Computer Program Listing Appendix of U.S. Pat. No. 7,347,855, which is incorporated herein by reference in its entirety. 
         [0089]    It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.