(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATIONTREATY(PCT)
`
`(19) World Intellectual Property Organization
`International Burcau
`
`(43) International Publication Date
`16 October 2008 (16.10.2008)
`
` (10) International Publication Number
`
`WO 2008/124112 Al
`
`(51)
`
`(21)
`
`(22)
`
`(25)
`
`(26)
`
`(30)
`
`(71)
`(72)
`
`(72)
`(75)
`
`(74)
`
`(81)
`
`International Patent Classification:
`
`A6IF 2/00 (2006.01)
`
`A6OIF 7/00 (2006.01)
`
`International Application Number:
`PCT/US2008/004478
`
`International Filing Date:
`
`7 April 2008 (07.04.2008)
`
`Filing Language:
`
`Publication Language:
`
`Priority Data:
`60/922,249
`
`English
`
`English
`
`6 April 2007 (06.04.2007)
`
`US
`
`Applicant and
`Inventor: FLOCK, Stephen [US/US]; 13379 West 61st
`Street, Arvada, CO 80004 (US).
`
`Inventor; and
`(for US only): MARCHITTO,
`Inventor/Applicant
`Kevin [US/US]; 15403 West 51st Place, Golden, CO
`80403 (US).
`
`Agent: ADLER, Benjamin, A.; Adler & Associated, 8011
`Candle Lane, Houston, TX 77071 (US).
`
`Designated States (unless otherwise indicated, for every
`kind of national protection available): AE, AG, AL, AM,
`
`AO,AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, CA,
`CII, CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE,
`EG,ES,FI, GB, GD, GE, GH, GM, GT, HN, HR, HU,ID,
`IL, IN, IS, JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC,
`LK, LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN,
`MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PG, PH,
`PL, PT, RO, RS, RU, SC, SD, SE, SG, SK, SL, SM, SV,
`SY, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN,
`ZA, ZM, ZW.
`
`(84) Designated States (unless otherwise indicated, for every
`kind of regional protection available): ARIPO (BW, GH,
`GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM,
`ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
`European (AT, BE, BG, CH, CY, CZ, DE, DK,EE,ES, FI,
`FR, GB, GR, HR, HU,IE,IS, IT, LT, LU, LV, MC, MT, NL,
`NO,PL, PT, RO, SE, SI, SK, TR), OAPI (BF, BJ, CF, CG,
`CI, CM, GA, GN, GQ, GW, MI, MR, NE, SN, TD, TG).
`
`Published:
`
`with international search report
`before the expiration of the time limit for amending the
`claims and to be republished in the event of receipt of
`amendments
`
`(54) Title:INDUCTIVE HEATING OF TISSUES USING ALTERNATING MAGNETIC FIELDS AND USES THEREOF
`
` (57) Abstract: With the present invention,
`
`it is possible to im-
`prove the cosmetic appearance of skin by controllably heating a
`superficial layer of skin thereby inducing acute tissue contraction
`or shrinkage and a wound response leading to the production of
`biomolecules, all of which result in improved cosmesis. The inven-
`tion incorporates a source of radio frequency electrical energy cou-
`pled to coil, with requisite impedance matching network, thereby
`resulting in the production of an alternating magnetic field. When
`tissue is brought into proximity of the alternating magnetic field,
`inductive heating of the tissuc results as a consequence ofcither or
`both of dipole formation and oscillation, and eddy current forma-
`tion. Optionally, cooling is provided to remove heat from the coil,
`the source of radio frequency clectrical energy, or the surface of
`the skin alone or in combination. The invention exhibits the sig-
`nificant benefits of, among other things, being non-invasive, not
`requiring electrical contact with the body of the subject, and pro-
`viding controllable heating only to a thin layer of tissue.
`‘The in-
`vention is useful not only for cosmetic procedures such as facial
`rejuvenation, wrinkle treatment, acne treatment, hair removal, vas-
`cular lesion treatment, varicose vein treatment, curing offillers, and
`treatmentof cellulite, but also for surgical procedures such as coag-
`ulation, cauterization or for induction of biomolecular events such
`as a woundresponse, production of heat-shock proteins or an in-
`flammatory responsein tissue.
`
`
`
`
`
`WO2008/124112AdIMITIITIINIITINIMAMERICATAYA
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`INDUCTIVE HEATING OF TISSUES USING ALTERNATING
`
`MAGNETIC FIELDS AND USES THEREOF
`
`BACKGROUND OF THE INVENTION
`
`Field of the invention
`
`The present invention relates generally to the fields of biomedical
`engineering, biochemistry, medical
`treatment, and surgical procedures. More
`specifically, the present invention provides methods, devices, and compositions for
`inducing changesin tissues, biomolecules, and bioactive molecules. These changes
`are notably useful for inducing alterations in tissues, most notably in skin, for
`cosmetic purposes.
`
`Description of the Related Art
`
`Heating of tissue is a fundamental physical event in manydifferent
`medical procedures. Depending on the time-temperature history of the tissue, a
`cascade of physical, chemical, and biological events occurs whentissue is heated.
`These events can lead to a beneficial or deleterious response. One example of a
`beneficial response is the reduction or elimination of the appearanceof skin wrinkles
`as a result of heat induced tissue contraction.
`
`Skin wrinkles
`
`Skin wrinkles are often the consequence of advancing age and sun
`exposure. With increasing age and excessive sun exposure, skin quality
`deteriorates. This is due, in part, to changes in hydration and epidermal thickness,
`and on a molecular scale, to a decrease in the amount of collagen in the dermis.
`Further, subcutaneous fat accumulates or atrophies leading to furrowing of the skin,
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`which produceswrinkles. In today's society, the appearance of skin wrinkles is often
`viewed negatively and so there is a desire in the community for a meansto safely
`reduce or eliminate wrinkles.
`
`Skin Rejuvenation
`
`For many years, wrinkles have been treated with chemical peels or
`mechanical dermabrasion, cosmetic medical procedures in which the surface of the
`epidermis of the skin (the stratum corneum) is removed chemically or by abrasion
`(sanding), respectively.
`In the late 1980s,
`laser ablation procedures for skin
`resurfacing were developed and approved. Today they remain in use, but are being
`replaced by laser procedures that are non- ablative and less damaging to
`surrounding tissues. The goal of these procedures includes tissue contraction, or
`
`skin-tightening, as well as induction of a wound response that leads to the
`
`generation of new collagen, and hence, dermai thickening. In the mid to late 1990s,
`another cosmetic technique for skin was developed that involves a non-ablative
`
`thermal alteration to skin. This procedure, referred to as radiofrequency (RF) skin
`
`rejuvenation, is mediated through capacitive-coupling of radiofrequency energy (e.g.
`
`U.S. Patent No. 7,189,230), using modified electrosurgical devices.
`
`Radiofrequency rejuvenation can result in tissue contraction as tissue
`
`structural proteins and proteoglycans thermally denature and coagulate. A second
`
`effect of this procedure is a beneficial wound response causing the production of
`
`new collagen. More recently, additional devices for skin rejuvenation have been
`
`developed that employ ultrasound, high-temperature plasma directed at the tissue,
`
`or radiofrequency electromagnetic fields.
`
`All of the current technology can result in deleterious effects in patients
`and create problems for the operators. For example,
`laser radiant energy is
`potentially hazardous to the operator and precautions must be madeto safely
`contain it, and patients often report burns resulting from laser treatments.
`
`radiofrequency devices work through capacitive-coupling
`Most
`wherebypotentially hazardous electrical current passes through the patient's body,
`resulting in the creation of radiofrequency electric fields at the interfaces of tissues
`
`

`

`WO 2008/124112
`
`-
`
`PCT/US2008/004478
`
`that are weak- or non-polarity. This effect capacitive coupling can lead to burns at
`electrodes, and inadvertent heating of collateral tissues, such as adiposetissue. This
`heating of collateral tissues is an undesirable consequencefor skin rejuvenation that
`can result in atrophy, particularly in fat layers in skin during cosmetic treatments.
`Further, generation of smoke and charring of tissue is a common consequence of
`the use of electrosurgical devices. For example, during surgery, an "inadvertent
`capacitor" can be created between a laparoscope and the electrosurgical probe,
`resulting in the creation of electrical currents where they are not expected.
`
`The instant invention eliminates the risk of charring and the generation
`of smoke, as it does not rely on capacitive coupling for its effects. The patientis
`isolated from the electrical current in the devices and no electrical current is
`conducted from the applicator or the patient. The invention preferably is used for the
`direct heating of moist conductive tissues, such as the viable dermis during cosmetic
`skin treatment, and less efficiently for tissues of low hydration (e.g. stratum
`corneum), or of low polarity (adipose), thereby providing a safer meansfor treating
`skin.
`
`Skin Cooling
`
`Whenviable tissues reach temperatures of 55C to 60C, tissue necrosis
`may occur. This is one concern during laser and radiofrequency cosmetic skin
`treatments. Thus, various methods of skin cooling are often employed (Anderson,
`RR, 2003), including the spraying of cryogen on the skin surface or on an applicator,
`or applying cold air, water or ice to the skin. One prior art method for the purpose of
`skin cooling is the application of ice cubes to the skin surface prior to laser treatment,
`(Gilchrest et al., 1982). These treatments have not proven entirely satisfactory, nor
`more importantly led to an improved therapeutic response,
`that
`is improved
`blanching of the port wine stain, (nevus flammeus), which is a vascular birthmark
`consisting of superficial and deep dilated capillaries in the skin that produce a
`reddish to purplish discoloration of the skin.
`
`Otherprior art. attempts to provide surface cooling of the epidermis
`using plastic bags filled with ice placed on the skin surface for five minutes,
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`compressed freon gas used during irradiation, or chilled water spread directly on the
`area being irradiated have also been explored, (Welch et al., 1983). However, these
`studies were done with pig cadaver tissue and normally utilized cooling periods of 2
`
`to 14 seconds. The reported results with freon were good in only 28.5 percent of the
`
`cases, in some cases, the skin surface was momentarily frozen, and in others, the
`
`freon jet was found to overcool the skin surface.
`
`Thus, the prior art is deficient in methods and devices for non-invasive
`
`and safer methods of skin rejuvenation induced by high frequency alternating
`magnetic fields that inductively heat skin tissues. The prior art is also deficient in the
`use of alternating magnetic fields to inductively heat conductive dermal tissues with a
`high degree of specificity. The prior art is also deficient in methods and devices to
`target during the skin rejuvenation process only conductive dermal tissue and have
`little effect on fat and skin surface tissues. The present invention fulfills this
`
`longstanding need anddesire in the art.
`
`SUMMARYOF THE INVENTION
`
`The present invention is directed to a method of treatmentof tissues in
`a subject, most notably for cosmetic treatment of skin. The method involves creating
`a high-frequency alternating magnetic field that, when directed in proximity with
`tissue, results in the production of heat through inductive coupling with the tissue
`thus resulting in the desired biologic effect. Representative examples of such
`biologic effects include, but are not limited to coagulation, cauterization, tissue
`contraction or shrinkage, and induction of a wound response that
`leads to
`biomolecular changes such asthe production of collagen bycells.
`
`The present invention also is directed to methods to coagulate tissue.
`The coagulation process may be beneficial in ablating tissue, fusing tissue, and in
`
`improving skin cosmesis.
`
`The present invention is directed furtherstill to a method of monitoring
`the treatment processin tissue. The heating process may be controlled by feedback
`monitoring and adjustment of the heating process in accord to the results. Methods
`
`4
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`of monitoring include, but are not limited to, detection heat generation, monitoring
`eddy current formation in the tissue, ultrasound detection of tissue alterations or
`changesin impedencein tissues that lead to an impedance mis-match between the
`magnetic field applicator and the radiofrequency generator.
`
`The presentinvention is yet directed furtherstill to a method of cooling
`the surface of the skin during a treatment with. The cooling method of the present
`invention preferably involves cooling of a thermally conductive surface in contact with
`the skin. This may be accomplished bycirculating coolant through the componentin
`contact with the surface of the skin, or the contact component may be cooled by
`circulating coolant through the device coil component, or by directing cryogenic liquid
`or gas on the surface of the skin,
`to the contact surface, or the device coil
`component, before, during or after treatment.
`
`The present invention is directed furtherstill to a method of inducing a
`beneficial wound responsein tissue by exposing the tissue to a high-frequency
`alternating magnetic field that induces the movement of charged species within the
`tissue leading to various biologic responses, some of which are induced by the
`concomitant production of heat in the tissue. One beneficial would responseis the
`production of new collagen in the skin and dermal thickening.
`
`The presentinvention is yet directed furtherstill to a device for altering
`tissue incorporating a source of electromagnetic energy, a cooling system, an
`induction coil, an impedence matching network, and optionally, a means of
`controlling the process.
`
`The presentinvention is directed further to a device for treating tissue
`incorporating a hand piece coupled to the energy output of a radiofrequency
`generator, whereby the hand piece incorporates an impedance matching network, a
`cooling system, and optionally a feedback mechanism to ensure propertreatment of
`the tissue. Optionally, a mechanical or pneumatic tissue-shaper, which can
`manipulate the tissue into a beneficial position and shape proximal to the hand piece
`is incorporated.
`
`The present invention is yet directed furtherstill to a device for altering
`tissue incorporating a source of electromagnetic energy, an induction coil, a cooling
`system, an impedance matching network, and a means of controlling the process
`
`5
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`through feedback monitoring by detection of eddy currents, or detection of an
`additional source of radiant energy, plasma energy, acoustic energy, bipolar
`
`electrosurgical energy, or monopolarelectrosurgical energy.
`
`Other and further aspects, features, and advantages of the present
`invention will be apparent from the following description of the presently preferred
`
`embodiments of the invention given for the purpose of disclosure.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`So that the matter in which the above-recited features, advantages and
`
`objects of the invention, as well as others that will become clear, are attained and
`can be understood in detail, more particular descriptions of the invention briefly
`summarized above may be hadby reference to certain embodiments thereof that are
`illustrated in the appended drawings. These drawings form a part of the specification.
`It
`is to be noted, however,
`that the appended drawings illustrate preferred
`embodiments of the invention and therefore are not to be considered limiting in their
`
`scope.
`
`Figure 1 depicts an applicator that transduces radiofrequencyelectrical
`
`energy into a magneticfield.
`
`Figure 2 depicts a hand piece incorporating a magnetic field applicator
`
`with optional cooling system.
`
`Figure 3 depicts the endplate of the hand piece.
`
`Figure 4 depicts a hand piece incorporating a solenoid-type inductor
`
`and positioning of tissue using pneumatic pressure.
`
`Figure 5 depicts a circuit diagram of the applicator.
`
`Figure 6 shows biopsied samples at each time point demonstrating a
`
`thickening of the dermis as compared to untreated controls.
`
`Figure 7 shows biopsied samples at each time point demonstrating a
`production of neo-collagen in treated tissues as compared to the untreated controls.
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`Figure 8 shows a modelof the expected modeof action produced by
`inductive heating on collagen within the treated tissues.
`
`Figure 9 shows measurements taken at 27MHz and 600W. Bovine
`muscle, bovine fat, ovine skin, and human blood were used for comparison. The
`tissues were cut to 2x2x5 cm samples. Each sample wasplaced directly on the cap
`of the 27MHz device and imaged from above with a Raytek IR thermometer. The
`device was activated and the time to heat was recorded. (n=3 for each tissue type).
`
`Figure 10 shows porcine fat, muscle and skin were used for
`comparison. The tissue samples were measuredfor thickness to ensure consistency
`between samples. The samples were between 1.5-2.0mm in thickness. The samples
`were placed on the faceplate which is 4mm thick PVC and imaged from above with a
`Raytek IR thermometer. The device was turned on and the time for the sample to
`reach 70°C was recorded. The IR thermometeris limited to recording the tissue
`surface opposite that which is in contact with the device. Therefore,it is believe that
`the actual temperature of the tissue was greater than indicated on the graph.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`One embodiment of the present invention provides a method of
`treatment for one or more tissue in an individual, comprising positioning an
`alternating magnetic field in proximity of the tissue,
`inducing heat therein, and
`thereby effecting treatment.
`
`Radiofrequency Power Supply
`
`The invention consists of a source of radiofrequency (RF) electrical
`energy, normally a radiofrequency generator such as sold by Comdel, Inc. (e.g.
`CV1000 or CV500, 40.68 MHz; Gloucester, MA). The electrical output of the
`generator is coupled to an applicator consisting of an inductor in the form of a coil
`(for the generation of a magnetic field), which is further part of an impedance
`matching network that may additionally comprise a capacitor.
`In some cases
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`applicator may include an antenna (for the production of an electrical field). The
`source of energy used may be a constant current or a constant voltage power supply
`or may be a modulated current or a modulated voltage power supply. The power-
`supply is able to produce radiofrequency energy with a powerin the range 10-10,000
`W and, depending on the application, may be more preferably in the range of about
`100 to about 1000 W. The power-supply maytypically operate at frequencies of 100
`kHz to 2.4 GHz. Preferably the frequency range is about 100 kHz to about 5.8 GHz
`and, more preferably, the frequency range is at or near, or between 415 kHz to 4
`MHz, 13.56 MHz, 27.12 MHz, 40.68, 67.8 MHz, 95 MHz, 433.92, 915 MHz, 2.4 GHz.
`
`The power-supply may optionally be one used in electrosurgery. Beneficially, the
`radiofrequency generator should be frequency-agile; that is, as the impedance ofthe
`load changes somewhat, the frequency output of the radiofrequency generator
`changesslightly to provide a better impedance match between the load and
`generator and so to maintain the output powerwithin a controllable tolerance.
`
`Applicator
`
`Fig. 1 is a sectional view of an applicator used to produce a magnetic
`field. A center copper tube 2220, which serves to conduct the radiofrequency
`electricity but also as an input for refrigerant, is surrounded by a TEFLON®cylinder
`2240. Endcaps 2230 and 2270 serveto position and hold the copper tube within the
`TEFLON®cylinder. The center copper tube 2220 is formed at the distal end of the
`applicator into a coil, 2280, which thenis fixed paralle] 2320 with the center copper
`tube and directed to an exit 2210 out of the applicator; the coolant is directed out
`through exit 2210.
`In order to provide impedance matching between the
`radiofrequency generator and applicator, a ceramic insulator 2310 is positioned
`around the TEFLON®cylinder 2240. The ceramic insulator has two capacitorrings,
`2330 and 2260, made up of copperpipe. The pipe 2320 is in electrical contact with
`the capacitor rings. By adjusting the spacing 2250 between the two capacitor rings,
`the impedance match between the radiofrequency generator and applicator can be
`effected. The applicator is encased in a copper cylinder 2450 attached to the ground
`shield of the coaxial wire in order to shield any stray radiated radiofrequency.
`
`

`

`WO 2008/124112
`
`Handpiece
`
`PCT/US2008/004478
`
`Fig. 2 shows a view of one design for a hand piece 3300, which is
`madeof an electrically non-conductive material such as plastic, which surrounds the
`applicator. The main housing 3500 is optionally attached to a disposable shield
`3350, which serves to maintain cleanliness of the part of the handpiece which comes
`into contact with the skin 4300. Optionally, the handpiece incorporates a coolant (for
`example, R-134a) contained in a housing 3520 and directed through a solenoid and
`pipe 3560 to an exit nozzle 3600. This coolant can be controllable directed to the
`treated tissue before, during and/or after the treatmentin orderto limit the heating of
`the very superficial skin.
`
`Cooling Endplate
`
`Fig. 3 shows a view of an endplate 3550 on the distal end of the hand
`piece housing 3500. The endplate is in intimate thermal contact with the coil 2280,
`which hascirculating refrigerant within, and so the endplate is cooled. This coolant
`may optionally be supplied from a circulating chiller utilizing water and antifreeze.
`Alternatively, gas such asair, nitrogen, freon, R-12, R-134a, and carbon dioxide
`could serve the purpose of cooling. Keeping in mind that the disposable shield 3350
`is very thin and/or is highly thermally conductive,
`it serves to cool the skin before,
`during and/orafter the treatment in orderto limit the heating of the very superficial
`skin and increase comfort for the subject. Fig. 3 also shows an optional Faraday
`shield 3450, which is a conductive element intended to reduce capacitive coupling of
`coil to the subject, and so to minimize anystray electric field. Note that the cooling
`endplate maybe in intimate contact with the coil in order to provide optimal thermal
`conduction. This may be accomplished by molding or by forming the plate around
`the coil. As shown in Figure 2, cooling of the skin may be realized by spraying the
`skin with a coolant before, during or after treatment.
`
`Pneumatic Applicator
`
`Fig. 4 shows a partial view of an applicator incorporating a two-turn
`solenoid coil 4450, the bore of which surround tissue 4260 which extrudes from the
`
`

`

`WO 2008/124112
`
`:
`
`PCT/US2008/004478
`
`skin 4300 up into the bore as a result of negative pneumatic pressure within the
`housing 3500. As the magnetic field within the turns of a solenoid is very much
`stronger than the field outside of a pancake coil, and the geometry ofthe tissue
`within the bore is different than illustrated in Fig. 2, the power required to obtain an
`effect is reduced andthe effect on tissue can be more beneficial.
`
`Combined Devices
`
`In some aspects of this embodiment, the treatment may be inductive,
`or conductively or radiatively applied in combination with the use of an alternating
`magnetic field. Additionally, the energy may be pulsed in order to improve the
`
`the tissue heating. Examples of applied energy are
`thermal kinetics of
`radiofrequency energy, radiant energy, or vibrational energy. The radiofrequency
`
`energy may have a frequency from about 20 kHz to about 40 GHz, and may be
`applied using coils, electrodes or one or more antennae. The radiant energy may
`have a wavelength from about 600 nm to 11m. The vibrational energy may be sonic
`
`or ultrasonic with a frequency from about 20Hz to 80 MHz. In the case of inductive
`
`heating, the energy may not be incident on the target, but may be induced in the
`
`target to be converted from one form to another.
`
`In certain aspects, combined devices, using induction plus an energy
`
`source (e.g. laser or ultrasound) may enhance the effects or be used to combine
`
`certain treatments. Because the interaction of laser energy and ultrasound waves
`
`with tissue is physically different than the present invention, it is anticipated that a
`
`different effect can be elicited. An applicator of radiant energy may consist of an
`optical assembly, which focuses the radiant energy on the relevant target or below
`the target surface, to get a sub-surface effect sparing the superior surface. A
`pressure-wave applicator may consist of a focused ultrasound transducer, whichis
`
`coupled to the target tissue with an acoustic impedance matching material, such as
`
`gelatin, mineral oil or glycerin.
`
`Feedback Monitoring and Safety Interlocks
`
`in its preferred embodiment (Fig. 1), where a magnetic field is
`
`produced, the heating effect in tissue tends to change the electrical properties of the
`
`10
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`impedance that the radiofrequency
`tissue. As the tissue alters the electrical
`generator sees, it is possible to use this change to monitor the heating process. For
`example, as the impedance of the skin changes, the impedance mismatch between
`the radiofrequency generator and the tissue/applicator increases and so the power
`reflected back into the radiofrequency generator increases.
`It
`is this increase in
`power that can be used as a signal to eventually halt the application of energy.
`Alternatively, the changein tissue can be detected using ultrasound or by detecting
`changesin eddy current formation.
`
`Asthe tissue treatment processis initiated, the applicator (Fig 1) and
`most notably the coil 2280, endplate (Fig. 3, 3550), and tissue heat up; when the
`radiofrequency energy ceases, they cool down. Such temperature changes can
`easily be monitored by devices such as thermocouples or thermistors. As such
`devices can behaveerratically in the presence of strong electromagnetic fields,
`devices such as infrared thermometers may be more suitable to monitor the
`
`temperatures.
`
`Transducers monitoring the temperature and power output of the
`
`radiofrequency generator, the reflected power into the generator, the presence of
`
`waterflow into the applicator (and generator,if it is required), and the presence of a
`
`short-circuit anywhere (indicted by a rapid rise in current in the generator and/or
`
`applicator, are an important safety feature in the present invention. Other optional
`
`safety interlocks include mechanical or electrical
`
`transducers between the
`
`disposable shield (Fig. 3, 3350) and the housing of the hand piece;if a shield is not
`
`present, the RF generator would not engage. Encoding of the interlock in the shield
`
`would ensure that a particular shield is only used on a particular patient. Thermal
`
`switches are incorporated within the device to shut it down if overheating occurs.
`Fast breakers quickly cut off the output if a power-output transient occurs. Multiple
`interlocks are incorporated within the device, which prevents running the device with
`
`the cover removed. A foot pedal optionally is incorporated in order to minimize the
`
`possibility of unintentional activation of the device.
`The induced magnetic field may also be actuated upon detection of a
`load. A relatively small current may be applied to the device while the device is not in
`
`proximity to a tissue target. As the device becomes proximal to the target, the
`
`11
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`change in impedanceis detectable, and this may be used as a signal to increase
`power to the device. This safety feature minimizes the exposure of the handpiece
`componentsto significant power load when the device is not applied to tissue, thus
`
`potentially reducing wear of the device.
`
`Methods of Treatment
`
`The device may be used to induce changesin tissue by applying
`alternating magnetic fields to the tissue such that currents are induced within the
`tissue (eddy currents). These currents encounter resistance and the result is the
`generation of heat. These eddy currents form mostefficiently where there is a moist,
`polar environment, thus enabling electron displacement or ion flow within the target.
`Thus, for example, in skin, the generation of eddy currents in the moist underlying
`dermis is favored over the superficial dehydrated epidermis and stratum corneum
`layers, and the underlying, more non-polar adipose layer. This results in preferable
`heating of conductive tissues over non- or weakly-conductive tissues.
`
`Variations in cooling of the skin surface may be achieved by increasing
`the volume of coolant to the device, or surface of the skin. These variations may be
`optimized to provide additional protection of the tissue proximal to the device from
`
`the effects of heating.
`
`A scaffold or lattice structure may be placed within tissues to provide
`support. The structure may befixed or fused in place using methods described
`herein. For example,
`localizing a scaffold made of polylactic acid, or a similar
`polymerin proximity to fat layers found in or under skin could prove beneficial in the
`treatment of cellulite fat. Cellulite produces an unattractive profile on the surface of
`skin due to the fat being squeezed betweentissue structures resulting in upwelling of
`"fingers" of fat, which then distend the skin surface. Cellulite’s cause is unclear,
`although it may result from fatty distension of the superficial fascia, which connects
`the dermis to the deep fascia. Attachmentpoints to the dermis may be patent while
`surrounding areas lose structure and bulge, producing the "cobblestone" appearance
`on the surface of the skin. By increasing the number of attachmentpoints, or by
`fixing a mesh-like substrate in place to minimize bulge, or by heating the fat to
`
`12
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`achieve melting and flowing into the scaffold, cosmesis may conceivably be
`improved. The devices and methods described herein may be used to heat and melt
`fat layers.
`
`Another embodiment of the present invention allows for treatment of
`
`acne, hair removal or treatment of varicose veins.
`
`It has been determined that the
`
`production of a critical amount of heat in tissue can lead to a cascade of events that
`results in a therapeutic effect. Acne can be treated by causing thermal damage in the
`affected skin, and hair removal can result from thermal damage to the hair follicles.
`The exact biologic mechanism behind these treatments is unclear, but tissue
`tightening mayplay a role. Alternatively, sublethal damage to the hair follicles can
`actually result in stimulating hair growth. Sublethal damage leads to a cascade of
`wound-response events such as the production of cytokines, interleukins and heat-
`shock proteins. These endogenous events can be beneficial and probably underly
`the salient events in, for example, stimulating hair-growth.
`In any case, the instant
`invention can induceall of these events.
`
`Treatment of skin wrinkles can sometimes employ botulism toxin,
`whereupon an injection of toxin in or around the nerves associated with the wrinkle
`
`temporarily relax the muscle leading to reduction in the appearance of the wrinkle.
`Recently, electrosurgical ablation of the nerve has been shownto result in a good
`cosmetic effect and may benefit from being permanent. The problem with
`electrosurgical ablation of the nerves are the same as the problems associated with
`electrosurgical generators in other procedures. The present invention provides a
`
`means with which to ablate the nerve in a non-contact mode.
`
`Coagulation is a very important technique in surgery asit provides a
`meansto kill tissue without dissection, thus eliminating potentially toxic smoke and
`char, and by not removing tissue, allowing for mechanical integrity to be maintained
`for a period of time. Standard electrosurgical and electrocautery devices usually
`produce smoke when used to coagulate tissue (smoke is a potential source of
`
`carcinogensor viruses), and dry tissue tendsto stick to the electrosurgical electrode
`
`which then results in re-bleeding when the electrode is removed from the treatment
`
`site. A non-contact way of coagulating tissue, using the instant invention, would be or
`
`paramount importance in surgery. The instant invention exhibits the benefit and
`
`13
`
`

`

`WO 2008/124112
`
`PCT/US2008/004478
`
`whenthe tissue is heated and dessicates, coupling between the magnetic field and
`
`tissue decreases thus limiting the heating and eliminating the possibility of smoke or
`
`charring.
`
`As described below, the invention provides a number of therapeutic
`advantages and uses, but such advantages and uses are not limited by such
`description. Embodiments of the present
`invention are be