US20070066978A1 - Ultrasound medical devices and related methods - Google Patents

Abstract

Ultrasound medical devices and related methods are described.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of U.S. application Ser. No. 60/714,456, filed on Sep. 6, 2005, which is incorporated by reference herein.
TECHNICAL FIELD
• This description relates to ultrasound medical devices and related methods.
BACKGROUND
• An ultrasound medical device can be used to treat a subject (e.g., a human) having certain conditions. Typically, a portion of the ultrasound medical device is disposed within the subject, and the ultrasound medical device is activated so that the portion of the ultrasound medical device disposed within the subject vibrates at an ultrasonic frequency. The ultrasonic vibrations can treat the condition (e.g., by breaking up tissue in the subject).
• For example, an ultrasound medical device can be used to treat an occluded blood vessel in a subject by disposing a portion of the ultrasound medical device within the blood vessel at a location adjacent the occlusion. The ultrasound medical device is subsequently activated so that the portion of the device adjacent the occlusion vibrates at an ultrasonic frequency, and the ultrasonic vibrations can break up the occlusion.
SUMMARY
• In one aspect of the invention, a method includes operating an ultrasound vibration element having proximal and distal ends so that the distal end of the ultrasound vibration element vibrates in a longitudinal direction of the distal end of the ultrasound vibration element, and a portion of the ultrasound vibration element vibrates in a direction perpendicular to the longitudinal direction of the distal end of the ultrasound vibration element. The portion of the ultrasound vibration element is between the proximal and distal ends of the ultrasound vibration element. The method further includes advancing the vibration element through an occlusion in a body vessel of a subject while the vibration element is being operated.
• In another aspect of the invention, a method includes vibrating a distal end of an ultrasound vibration element in a longitudinal direction, and vibrating a portion of the ultrasound vibration element proximal to the distal end in a direction perpendicular to the longitudinal direction. The distal end of the vibration element is disposed adjacent an occlusion in a body vessel. The method further includes advancing the ultrasound vibration element through the occlusion while vibrating the distal end in the longitudinal direction.
• In an additional aspect of the invention, a method includes advancing an ultrasound vibration element through an occlusion of a body vessel while vibrating a distal end of the ultrasound vibration element in a longitudinal direction.
• Embodiments can include one or more of the following features.
• In some embodiments, the body vessel is a blood vessel.
• In certain embodiments, the method further includes disposing the distal end of the ultrasound vibration element in the occlusion in the blood vessel of the subject.
• In some embodiments, the longitudinal vibration of the distal end of the ultrasound vibration element is used to advance the ultrasound vibration element through the occlusion in the blood vessel of the subject.
• In certain embodiments, the method further includes at least partially breaking up the occlusion in the blood vessel of the subject.
• In some embodiments, the vibration of the portion of the ultrasound vibration element is used to at least partially ablate the occlusion in the blood vessel of the subject.
• In certain embodiments, the vibration element includes a wire.
• In some embodiments, operating the vibration element includes delivering electrical energy to an assembly that is coupled to the vibration element, the assembly being configured to convert electrical energy to mechanical energy.
• In certain embodiments, the assembly includes an acoustic horn.
• In some embodiments, the method is used to treat a chronic total occlusion, to debulk the prostate, to treat gynecological tissue, to remove bone cement, or to perform phacoemulsification.
• In certain embodiments, the method is used to treat deep vein thrombosis, urolithiasis, and/or peripheral arterial disease.
• Embodiments can include one or more of the following advantages.
• Generally, the systems can be designed for relatively safe, easy and effective use.
• The systems can be designed to allow for accurate and dynamic adjustments (e.g., in the output of the power supply) in the vibrational frequency of an acoustic assembly in the system so that the vibrational frequency of the acoustic assembly is appropriately matched to a resonant frequency (e.g., the fudamental resonant frequency or a harmonic of the fundamental resonant frequency) of the acoustic assembly. This can, for example, enhance the safety and/or enhance the efficiency of the systems. As an example, this design can reduce the possibility of the acoustic assembly vibrating at an inappropriate frequency for a given procedure. As another example, this design can reduce inefficiencies associated with a mismatch between the frequency at which the acoustic assembly is driven and the frequency at which the acoustic assembly should be driven to be appropriately matched to its resonant frequency.
• The optional storage of one or more operational parameters in a memory located in the hand piece assembly can, for example, enhance the safety of systems that include the hand piece assembly. As an example, the operational parameters can identify the hand piece assembly and the procedures for which the hand piece assembly is properly used. As another example, the number of operational parameters input by a user can be reduced, thereby reducing the possibility of user error introduced by inputting.
• Other aspects, features, and advantages will be apparent from the description and claims.
DESCRIPTION OF DRAWINGS
• FIG. 1 is a schematic drawing of an ultrasound vibration system.
• FIG. 2 is a schematic diagram of a portion of an ultrasound vibration system when activated.
• FIGS. 3 through 6 are schematic drawings of a method of using an ultrasound vibration system to treat an occluded blood vessel.
• FIGS. 7A and 7B are schematic perspective and top views, respectively, of a hand piece assembly.
• FIG. 8 is a sectional view of the hand piece assembly ofFIGS. 7A and 7B.
• FIGS. 9A to9D are perspective, alternative perspective, side and sectional views, respectively, of an acoustic coupler.
• FIGS. 10A to10C are perspective, alternative perspective, and cross sectional views, respectively, of another acoustic coupler.
• FIGS. 11A to11C are schematic perspective, side, and sectional views, respectively, of a portion of hand piece assembly.
• FIGS. 12A to12C are schematic perspective, side, and sectional views, respectively, of a portion of another hand piece assembly.
• FIGS. 13A and 13B are schematic side and end views, respectively, of a wire.
• FIG. 14 is a schematic view of an acoustic horn as modeled with a finite element analysis.
• FIGS. 15A to15C are graphs showing nodal displacement versus longitudinal position for a proximal portion, a distal portion, and the entire length of the acoustic horn, respectively, for the horn ofFIG. 14 and achieved using finite element analysis.
• FIG. 16 is a schematic drawing of a portion of an ultrasound vibration system.
• FIG. 17 is a flow chart of an initialization and activation/operation process for an ultrasound vibration system.
• FIG. 18 is a flow chart of a process for modifying the vibrational frequency of an acoustic assembly of a handpiece during use of an ultrasound vibration system.
• FIG. 19 is a graph of a voltage signal and a current signal where the phase difference between the signals is non-zero.
• FIG. 20 is a graph of a voltage signal and a current signal where the phase difference between the signals is zero.
• FIG. 21 is a block diagram of a system designed to adjust the vibrational frequency of an acoustic assembly of a handpiece during use of an ultrasound vibration system.
• FIG. 22 shows a process for determining the initial center frequency for the output voltage of a voltage controlled oscillator.
• FIG. 23 shows a maximum range of values for an input voltage for a voltage controlled oscillator.
• FIG. 24 is a flow chart of a process for modifying the center frequency of the output voltage of a voltage controlled oscillator.
• FIG. 25 shows an exemplary process for enabling/disabling a hand piece assembly.
• FIG. 26 shows a process for confirming activation of a hand piece assembly.
• Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
• FIG. 1 shows anultrasound vibration system1000 that includes apower supply2000, ahand piece assembly3000 and an Ti-6Al-4V titanium wire4000.Power supply2000 is in electrical communication withhand piece assembly3000, andhand piece assembly3000 is mechanically coupled withwire4000. As explained in detail below,power supply2000 provides electrical energy (e.g., an oscillating voltage) tohand piece assembly3000, andhand piece assembly3000 converts this electrical energy to mechanical energy in the form of ultrasonic vibrations in an acoustic horn assembly3500 (shown inFIG. 8) of hand piece assembly3000 (e.g., ultrasonic vibrations at a resonant frequency ofacoustic horn assembly3500 of hand piece assembly3000). The ultrasonic vibrations withinacoustic horn assembly3500 ofhand piece assembly3000 are transferred towire4000. Without wishing to be bound by theory, it is believed that the ultrasonic vibrations ofwire4000 can effect biological material (e.g., tissue, plaque, thrombus, kidney stones, biliary stones, etc.) in a subject directly, indirectly or both. It is believed that direct effects ofwire4000 on the biological material can involvewire4000 directly contacting the biological material aswire4000 vibrates, and/orwire4000 creating ultrasonic vibrations in body fluid (e.g., blood)adjacent wire4000 that are directly communicated to the biological material. It is believed that an indirect effect ofwire4000 on the biological material can involve the creation of bubbles in the body fluid (e.g., blood) adjacent the biological material, where the bubbles expand and collapse to create a hydraulic shock in the body fluid that is communicated to the biological material. This expansion and collapse of the bubbles in the body fluid is commonly referred to as cavitation.
• FIG. 2 shows a representation ofwire4000 while vibrating. The vibrations inwire4000 includenodes4050 and anti-nodes4060.Nodes4050 are locations of minimum amplitude vibration ofwire4000, andanti-nodes4060 are locations of maximum amplitude vibration ofwire4000.
• The type of vibrational modes inwire4000 are generally selected based on the intended use of ultrasound vibration system1000 (e.g., the condition to be treated with system1000). In general, the vibrations ofwire4000 can be transverse modes (modes for which the vibration is perpendicular to the longitudinal axis of wire4000), longitudinal modes (modes for which the vibration is parallel to the longitudinal axis of wire4000), or combinations thereof.FIG. 2 shows an embodiment wherewire4000 is undergoing transverse vibration. In some embodiments, however, one or more portions ofwire4000 can undergo transverse vibration while one or more other portions ofwire4000 undergo longitudinal vibration. For example, when breaking up an occlusion in a blood vessel, it may be desirable for the distal end ofwire4000 to undergo longitudinal vibration (to allowwire4000 to penetrate into the occlusion) and for a more proximal portion of wire4000 (e.g., the portion ofwire4000 proximally adjacent the distal end of wire4000) to undergo transverse vibration (to break up the occlusion).
• In general, the spacing ofnodes4050 andanti-nodes4060 is selected based on the intended use of ultrasound vibration system1000 (e.g., the condition to be treated with system1000). Generally,nodes4050 can be evenly spaced or unevenly spaced, andanti-nodes4060 can be evenly spaced or unevenly spaced. In some embodiments, some ofnodes4050 are evenly spaced and some ofnodes4050 are unevenly spaced. In certain embodiments, some ofanti-nodes4060 are evenly spaced, and some ofanti-nodes4060 are unevenly spaced.FIG. 2 shows an embodiment wherenodes4050 are evenly spaced, andanti-nodes4060 are evenly spaced.
• Generally, the number ofnodes4050 andanti-nodes4060 present alongwire4000 is selected based on the intended use of system1000 (e.g., the condition to be treated with system1000). As an example,FIG. 2 shows an embodiment where there are fivenodes4050 and six anti-nodes.4060 present alongwire4000. In some embodiments, there can be fewer than five (e.g., one, two, three, four)nodes4050 or more than five (e.g., six, seven, eight, nine, 10)nodes4050 present alongwire4000. In certain30 embodiments, there can be fewer than six (e.g., one, two, three, four, five)nodes4060 or more than six (e.g., seven, eight, nine, 10)nodes4060 present alongwire4000.
• The amplitude ofanti-nodes4060 is generally selected based on the intended use of system1000 (e.g., the condition to be treated with system1000). In some embodiments, the amplitude ofanti-nodes4060 can be at least about five microns (e.g., at least about 10 microns, at least about 15 microns, at least about 20 microns, at least about 25 microns) and/or at most about 500 microns (e.g., at most about 400 microns, at most about 300 microns, at most about 250 microns). In certain embodiments, the amplitude ofanti-nodes4060 can be from about 10 microns to about 500 microns (e.g., from about 15 microns to about 400 microns, from about 20 microns to about 300 microns, from about 25 microns to about 250 microns).
• In general, the frequency of the vibrations inwire4000 is selected based on the intended use of system1000 (e.g., the condition to be treated with system1000). In some embodiments, the frequency of the vibrations inwire4000 is at least about 10 kHz (e.g., at least about 15 kHz, at least about 20 kHz, at least about 30 kHz) and/or at most about 100 kHz (e.g., at most about 90 kHz, at most about 80 kHz, at most about 70 kHz). In certain embodiments, the frequency of the vibrations inwire4000 is from about 10 kHz to about 100 kHz (e.g., from about 15 kHz to about 90 kHz, from about 20 kHz to about 80 kHz, from about 30 kHz to about 70 kHz, from about 35 kHz to about 45 kHz, from about 37 kHz to about 43 kHz, from about 39 kHz to about 41 kHz, about 40 kHz).
• For a given design ofhand piece assembly3000 and configuration ofwire4000, the type and frequency of vibrations in wire4000 (transverse and/or longitudinal), as well as the spacing, number and amplitude ofanti-nodes4060, is determined by the frequency of the output voltage ofpower supply2000. In general, the frequency of the output voltage ofpower supply2000 is at least about 10 kHz (e.g., at least about 15 kHz, at least about 20 kHz, at least about 30 kHz) and/or at most about 100 kHz (e.g., at most about 90 kHz, at most about 80 kHz, at most about 70 kHz). In some embodiments, the frequency of the output voltage ofpower supply2000 is from about 10 kHz to about 100 kHz (e.g., from about 15 kHz to about 90 kHz, from about 20 kHz to about 80 kHz, from about 30 kHz to about 70 kHz, from about 35 kHz to about 45 kHz, from about 37 kHz to about 43 kHz, from about 39 kHz to about 41 kHz, about 40 kHz).
• Ultrasound vibration system1000 can be used to treat a variety of conditions. For example,FIGS. 3-6 show an embodiment in whichsystem1000 is used to treat anocclusion5000 in ablood vessel6000 of a subject (e.g., a human). Referring toFIG. 3,wire4000 is disposed withinblood vessel6000 at a location that isadjacent occlusion5000.FIG. 4 shows that, afterpower supply2000 is activated to provide electrical energy tohand piece assembly3000, adistal end4001 ofwire4000 undergoes longitudinal vibration, allowingwire4000 to penetrate intoocclusion5000. As shown inFIGS. 5 and 6, aportion4002 ofwire4000 that is proximal todistal end4001 undergoes transverse vibration to break upocclusion5000.
• Referring toFIGS. 7A and 7B,hand piece assembly3000 includes ahand piece body3100 connected topower supply2000 at aproximal end3105 by amulti-wire cable2012 and threadably connected to anose cone3115 at adistal end3120. Anirrigation coupler hub3125 is attached tonose cone3115 and includes anirrigation coupler port3130 for connection to a fluid source (e.g., for use in embodiments where a catheter surroundswire4000 so that a fluid can flow betweenwire4000 and the catheter to irrigate the region adjacent the biological material being treated and/or to cool the wire during use).Wire4000 extends longitudinally fromdistal end3120 ofhand piece assembly3000 through a central bore alongcoupler hub3125.Hand piece body3100 includes apower switch3135 to controlpower supply2000 and an indicator light7140 to indicate the operational status ofsystem1000.Power switch3135 is a touch switch for which a first push places switch3135 in a first state (e.g.,power supply2000 on) and a second push places switch3135 in a second state (e.g.,power supply2000 off).
• FIG. 8 shows the internal components of thehand piece assembly3000 including anacoustic horn assembly3500 generally extending longitudinally fromproximal end3105 ofhand piece body3100 towarddistal end3120 ofhand piece body3100.Acoustic horn assembly3500 includes adistal horn3510, abackmass3515 and a plurality of piezoelectric transducers (e.g., piezoceramic rings)3520 disposed betweenhorn3510 andbackmass3515.Distal horn3510 is mechanically connected (e.g., via a threaded connection) to a proximal side of anacoustic coupler3700, andwire4000 is metallurgically bonded to a distal side ofacoustic coupler3700. With this arrangement, during use ofsystem1000,power supply2000 provides electrical energy in the form of an oscillating voltage topiezoelectric transducers3520, andpiezoelectric transducers3520 convert the electrical energy to mechanical energy in the form of vibrational energy that is transmitted towire4000 viaacoustic coupler3700.
• Acoustic horn assembly3500 is secured toproximal end3105 ofhand piece body3100 by aproximal mount3530 configured to house thebackmass3515. Atapered fitting3535 is attached to theproximal end3105 and extends from theproximal mount3530 to aflexible collar3540 surrounding the terminal end ofcable2012. Aspacer3545 is disposed betweenpiezoelectric transducers3520 and thebackmass3515.Acoustic horn assembly3500 is secured todistal end3120 ofhand piece body3100 by a plurality ofball bearings3550, a mountingring3555 including silicone o-rings3560,3565 along inner and outer surfaces, respectively, and afront retainer ring3570.Ball bearings3550, mountingring3555, andfront retainer ring3570 are all disposed betweenhand piece body3100 anddistal horn3510.Dimples3573 are positioned alongdistal horn3510 and receiveball bearings3550.Front retainer ring3570 includes external threads engaging corresponding internal threads ofhand piece body3100 such that rotation ofretainer ring3570 compressesacoustic horn assembly3500 andpiezoelectric transducers3520.Retainer ring3570 can include spanner wrench holes3575 for receiving a tool to permit rotation ofring3570 to a predetermined torque.
• As noted above,acoustic coupler3700 is metallurgically bonded (e.g., welded) towire4000 to allow vibrational energy to be transmitted frompiezoelectric transducers3520 towire4000. Generally,acoustic coupler3700 andwire4000 can be metallurgically bonded at any desired location withinacoustic coupler3700.
• As an example,FIGS. 9A through 9D show an embodiment in which anacoustic coupler3700ais metallurgically bonded towire4000 at alocation3745aadjacent aproximal end3705aofacoustic coupler3700a.Acoustic coupler3700aincludesexternal threads3710aalong aproximal end3705ato threadably connect to corresponding internal threads of the distal horn3510 (FIG. 8). Alternatively or additionally,acoustic coupler3700acan includeinternal threads3710aalong aproximal end3705ato threadably connect to corresponding external threads of thedistal horn3510.Wrench flats3715apermit rotation ofacoustic coupler3700aagainst thedistal horn3510 to a predetermined torque. Aflange3720aextends around a central portion ofcoupler3700aand engagesdistal horn3510 when attached thereto. Amain bore3725aextends from anopening3730aat adistal end3735aofcoupler3700ato a proximal bore3740a.Wire4000 extends throughbores3725aand3740a, and, as noted above, is bonded withcoupler3700aatlocation3745a.
• As another example,FIGS. 10A through 10C show an embodiment in which anacoustic coupler3700bis metallurgically bonded towire4000 at alocation3745badjacent adistal end3735bofacoustic coupler3700b.Acoustic coupler3700bincludesexternal threads3710bto threadably connect to corresponding internal threads of distal horn3510 (FIG. 8).Wrench flats3715bpermit rotation ofcoupler3700bagainstdistal horn3510 to a predetermined torque. Aflange3720bextends around a central portion ofcoupler3700band engagesdistal horn3510 when attached thereto. Amain bore3725bextends from anopening3730bat aproximal end3705bofcoupler3700bto adistal bore3740b.Wire4000 extends throughbores3725band3740band, as noted above, is bonded withcoupler3700batlocation3745b.
• Typically,wire4000 is metallurgically bonded with the acoustic coupler as follows.Wire4000 is disposed within the acoustic coupler. The acoustic coupler andwire4000 are then heated at a region where the metallurgical bond is desired (e.g., adjacent a proximal end of the acoustic coupler, adjacent a distal end of the acoustic coupler). Heating can be achieved using a variety of techniques, such as, for example, welding (e.g., arc welding). Generally, the heated region ofwire4000 and the acoustic coupler are brought to a temperature sufficient to form a metallurgical bond without substantially altering the physical properties ofwire4000 and the acoustic coupler.
• In some embodiments, locations of bonding3745a,3745bare relatively close to ananti-node4060 of the ultrasonic vibrations ofwire4000 during use ofsystem1000. Without wishing to be bound by theory, it is believed that such an arrangement of a bond location can improve the ultrasonic transfer efficiency ofsystem1000 and/or decrease localized heating in system1000 (e.g., localized heating in the ultrasonic coupler and/or wire40000 during use of system1000).
• In certain embodiments, the diameter ofopenings3730a,3730bincouplers3700a,3700bis about the same as the cross-sectional diameter ofwire4000. For example, in some embodiments, the cross-sectional diameter ofwire4000 is at least about 75% (e.g., at least about 85%, at least about 95%) of the cross-sectional diameter ofopenings3730a,3730b. Without wishing to be bound by theory, it is believed that using a cross-sectional diameter foropenings3730a,3730bthat is similar to the cross-sectional diameter ofwire4000 can improve the ultrasonic transfer efficiency ofsystem1000.
• As used herein, the term “ultrasonic transfer efficiency” is the ratio X:Y, where X is the amount of electrical energy (in the form of an oscillating voltage) output bypower supply2000 tohand piece assembly3000, and Y is the amount of mechanical energy in wire4000 (in the form of ultrasonic vibrations in wire4000). In certain embodiments,system1000 has an ultrasonic transfer efficiency of about 1:10 (or about ten percent) or greater.System1000 can, for example, have an ultrasonic transfer efficiency of about 1:10 (or about ten percent) to about 1:2 (or about 50 percent).
• In some embodiments, after assembly and prior towire4000 being bent, the combined length ofwire4000 and the acoustic coupler in the longitudinal direction of wire4000 (referred to as the relevant length) is equal to about five wavelengths, about 11 wavelengths, or about 13 wavelengths of an ultrasonic vibration. For example, forcoupler3700a, the relevant length is the length ofwire4000 in the longitudinal direction, and, forcoupler3700b, the relevant length is the length fromproximal end3705bto the distal end ofwire4000. In certain embodiments,wire4000 has a length substantially equal to the product of one-quarter wavelength and an odd multiplier (e.g., about 5¼ wavelengths, about 11¼ wavelengths, or about 13¼ wavelengths).
• Typically, part of the path of electrical communication betweenpiezoelectric transducers3520 andpower supply2000 includes one or more electrodes and one or more leads. As an example,FIGS. 11A through 11C showacoustic horn assembly3500 attached tocoupler3700a,electrodes3800 in electrical communication withpiezoelectric transducers3520, and leads3805 in electrical communication withelectrodes3800. As another example,FIGS. 12A though12C showacoustic horn assembly3500 attached tocoupler3700b,electrodes3800 in electrical communication withpiezoelectric transducers3520, and leads3805 in electrical communication withelectrodes3800. As also shown inFIGS. 12A through 12C, in some embodiments, leads3805 connect to amemory3014 inhand piece assembly3000.Memory3014 can transmit information to and frompower supply2000 over cable2012 (see discussion below).
• Examples of materials from whichdistal horn3510 can be formed include metals (e.g., titanium, stainless steel, aluminum) and alloys.
• Examples of materials from which backmass3515 can be formed include metals (e.g., titanium, stainless steel) and alloys.
• Generally, piezoelectric transducers can be formed of any appropriate materials. Examples of materials include piezo-ceramic materials, such as barium titanate and lead-zirconate-titanate. Suitable lead-zirconate-titanates are available commercially in a variety of compositions, including PZT-4 (Navy Type I), PZT-8 (Navy Type III).
• In some embodiments,acoustic coupler3700 is made from a metal (e.g., titanium, stainless steel, aluminum) and/or one or more alloys.
• In general,electrodes3800 can be formed of any sufficiently electrically conductive material. Exemplary materials include metals (e.g., nickel) and alloys (e.g., beryllium copper alloy, phosphor bronze alloy).
• Referring toFIGS. 13A and 13B, (unbent)wire4000 has aproximal end4010, adistal end4020 and alongitudinal axis4015 that extends between ends4010 and4020. Anacoustic coupler3700 is adjacentproximal end4010 ofwire4000.Wire4000 includes a series oftransformer sections4025,4030,4035, and4040, across a plurality oftransitions4050a,4050b,4050c.Transformer sections4025,4030,4035 and4040 have diameters D₁, D₂, D₃and D₄, lengths L₁, L₂, L₃and L₄, and cross-sectional areas A₁, A₂, A₃and A₄, all respectively. The physical properties and dimensions oftransformer sections4025,4030,4035 and4040 impact the characteristics of the ultrasonic vibrations present intransformer sections4025,4030,4035 and4040. As a result, the properties of the ultrasonic vibrations (e.g., type of vibrations, frequency of vibrations, amplitude of vibrations, spacing between nodes, spacing between anti-nodes, number of nodes, number of anti-nodes) in each section ofwire4000 may be the same as or different from the properties of the ultrasonic vibrations in one or more other sections ofwire4000.
• As an example, the ratio of the diameters of adjacent transformer sections ofwire4000 impacts the ratio of the amplitudes of the vibrations in these sections ofwire4000. For example, the ratio D₁:D₂impacts the ratio of the amplitude of the vibrations insection4025 to the amplitude of the vibrations insection4030. In general, as the ratio of adjacent diameters increases (e.g., as the ratio D₁:D₂increases), the ratio of the vibrational amplitude in the adjacent sections (e.g., the ratio of the vibrational amplitude insection4025 to the vibrational amplitude in section4030) also increases, and as the ratio of adjacent diameters decreases (e.g., as the ratio D₁:D₂decreases), the ratio of the vibrational amplitude in the adjacent sections (e.g., the ratio of the vibrational amplitude ofsection4025 to the vibrational amplitude in section4030) also decreases.
• As another example, the ratio A:B, where A is the ratio of the diameter to the length in one section ofwire4000 and B is the ratio of the diameter to the length in an adjacent section ofwire4000, impacts the potential for a transition from a longitudinal vibrational mode to a transverse vibrational when going from one section to the adjacent section. In general, as the ratio A:B increases (e.g., as the ratio A₄₀₂₅:B₄₀₃₀increases), the potential for changing from a longitudinal vibrational mode to a transverse vibrational mode when going from the first section to the adjacent section (e.g., when going fromsection4025 to section4030) also increases, and as the ratio A:B decreases (e.g., as the ratio A₄₀₂₅:B₄₀₃₀decreases), the potential for changing from a longitudinal vibrational mode to a transverse vibrational mode when going from the first section to the adjacent section (e.g., when going fromsection4025 to section4030) also decreases.
• As a further example, the ratio of the flexural stiffness of adjacent transformer sections ofwire4000 also impacts the potential for going from a transverse vibrational mode to a longitudinal vibrational mode when going from one section ofwire4000 to the adjacent section ofwire4000. For example, going from a section ofwire4000 that has a relatively high flexural stiffness to an adjacent section ofwire4000 that has a relatively low flexural stiffness tends to increase the potential for changing from a longitudinal vibrational mode to a transverse vibrational mode, and going from a section ofwire4000 that has a relatively low flexural stiffness to an adjacent section ofwire4000 that has a relatively high flexural stiffness tends to decrease the potential for changing from a longitudinal vibrational mode to a transverse vibrational mode.
• In general, consideration is also given to the intended use of system1000 (e.g., the condition to be treated with system1000) when selecting the dimensions ofsections4025,4030,4035 and4040. As an example, the diameters of the transformer sections of wire should not be so large as to preventwire4000 from being able to fit within a desired portion (e.g., blood vessel) of a subject to be treated. As another example, the dimensions ofwire4000 can be selected so thatwire4000 is sufficiently flexible so thatwire4000 can be navigated through the relevant portions (e.g., the vasculature) of a subject to be treated. As a further example,wire4000 should be sufficiently long so that the length of the portion ofwire4000 that is to undergo ultrasonic vibration during use of system1000 (e.g., the length ofsections4025,4030,4035 and/or4040) can reach a desired portion (e.g., an occlusion in a blood vessel) of a subject to be treated.
• Wire4000, as illustrated inFIGS. 13A and 13B, decreases in diameter from its proximal end toward its distal end. As a result, the amplitude of transverse vibrations inwire4000 generally increase from its proximal end to its distal end, and the amplitude of longitudinal vibrations inwire4000 generally decrease from its proximal end to its distal end. In some embodiments,wire4000 is configured so that distalmost section4040 has the greatest transverse vibrational amplitude alongwire4000 and is sized such thatsection4040 can reach the desired portion of the subject to be treated.
• In general,wire4000 can be prepared as desired. In some embodiments,wire4000 is prepared using a process that involves little or no plastic deformation and/or work hardening of the material that formswire4000. In certain embodiments,wire4000 is prepared using a process that creates little or no change in the mechanical and/or acoustic properties of the material that formswire4000.
• An exemplary process for preparingwire4000 is as follows. The transformer sections ofwire4000 are formed by grinding with a grinding wheel while exposingwire4000 to a lubricant. The grinding wheel is made of a material that is sufficiently hard to reduce the diameter ofwire4000 to form the transformer sections ofwire4000. An example of a grinding wheel material is silicone carbide. Examples of lubricants that can be used include oils (e.g., water soluble oils).
• In some embodiments, designingsystem1000 can involve using finite element analysis to model one or more components insystem1000. For example,FIG. 14 shows anacoustic horn assembly3500aas modeled using finite element analysis.Acoustic horn assembly3500ahas aproximal end3505a, adistal horn3510a, anose cone3115aandtransducers3520a. Anacoustic coupler3700cis attached toacoustic horn assembly3500a. The average distance oftransducers3520afromproximal end3505ais 1.12 inches.Distal horn3510aengages hand piece body at the dimples along ball bearings (see discussion above) at a location that is 3.28 inches fromproximal end3505a. The distance fromproximal end3505aofacoustic horn assembly3500ato a distal end3735cofacoustic coupler3700cis 4.68 inches.Proximal end3505ais 3.507 inches from the proximal end ofnose cone3115ais 3.507.
• FIGS. 15A through 15C are graphs of the longitudinal mode displacement as a function of the position alongacoustic horn assembly3500a, as modeled using finite element analysis and based on the model shown inFIG. 14.FIG. 15A shows that a first node is located 1.12 inches fromproximal end3505a.FIG. 15B shows that a second node is located 3.28 inches fromproximal end3505a.FIG. 15C shows the longitudinal mode displacement along the entire length ofacoustic horn assembly3500a. As shown inFIG. 15C,acoustic horn assembly3500asupports a full wavelength along its length. Thus,FIGS. 14 and 15A through15C show that, based on modeling data, an acoustic horn assembly can be designed that supports a full wavelength along its length, has a first node located at its transducers, and has a second node located where the hand piece body contacts the distal horn.
• Other designs can also be modeled using finite element analysis. For example, without wishing to be bound by theory, it is believed that locating a node at the acoustic coupler can adversely affect the propagation of ultrasonic vibrations along the wire. It is therefore believed that it can be desirable forsystem1000 to be designed so that a node is not present at the acoustic coupler (whetherwire4000 is bent or unbent). In certain embodiments, an acoustic horn assembly can be configured so that modeling using finite element analysis shows that the acoustic horn assembly supports a node at a first location proximal to, but not at, the acoustic coupler when the wire is unbent, and supports a node at a second location (different from the first location) that is proximal to, but not at, the acoustic coupler when the wire is bent (e.g., when the wire is disposed within a tortuous vessel).
• As discussed above,power supply2000 is in electrical communication withhand piece assembly3000.FIG. 16 shows thatpower supply2000 is electrically connected to handpiece assembly3000 bymulti-wire cable2012 so thatpower supply2000 can deliver electrical energy tohand piece assembly3000. In addition to providing an electrical energy path frompower supply2000 tohand piece assembly3000,cable2012 provides a communication path betweenpower supply2000 andhand piece assembly3000 so that information (e.g.,operational parameters3016 for system1000) can be transferred betweenpower supply2000 andhand piece assembly3000. For example, in some embodiments,multi-wire cable2012 includes a first wire for communicating information betweenhand piece assembly3000 andpower supply2000 and a second wire for transmitting power frompower supply2000 to hand piece assembly3000 (e.g., topiezoelectric elements3520 ofacoustic horn assembly3500 of hand piece assembly3000). In addition,multi-wire cable2012 can include a third, ground wire.
• Power supply2000 includes acontrol unit2002, a user interface/display2004, aninput device2006, a voltage controlled oscillator (VCO)2008, and amemory2010.
• Control unit2002 monitors and adjusts the operation of ultrasound vibration system1000 (see discussion below).
• User interface/display2004 provides a visual display onpower supply2000. User interface/display2004 can display various information, such as instructions for a user, status information (e.g., information that indicates whether the ultrasound vibration system1000 is on or off, information that indicates whether power is being supplied to hand piece assembly3000, information that indicates the amount of time left before system1000 will disable hand piece assembly3000), operational parameters (e.g., a voltage output of VCO2008, a current delivered to hand piece assembly3000, a temperature of acoustic horn assembly3500, identification information for hand piece assembly3000, a resonant frequency of acoustic horn assembly3500, a temperature of wire4000, a resonant frequency of wire4000), messages (e.g., a message displaying the company name, a message indicating that a calibration is needed, a message reporting a malfunction, a message indicating a reason for deactivation of hand piece assembly3000, a message reporting the source of an error in system1000, a message requesting action or feedback from an operator, a message displaying a current state of system1000), alarms (e.g., alarms indicating a warning of a failure in the system1000, such as an alarm indicating that a battery is low, an alarm indicating that the temperature of hand piece assembly3000 is above a predetermined value, an alarm indicating a maximum activation period of hand piece assembly3000 has been exceeded, an alarm indicating that a maximum post-activation use period of hand piece assembly3000 has been exceeded), or combinations thereof.
• Input device2006 allows a user to program or modify certain operational parameters ofultrasound vibration system1000.Input device2006 can be, for example, a keyboard, a mouse, a touch screen, one or more control knobs, one or more buttons, one or more switches, or a combination thereof.
• VCO2008 is in electrical communication withhand piece assembly3000 and provides an oscillating voltage (e.g., a sinusoidal voltage) tohand piece assembly3000 that causeswire4000 to vibrate during use. In general, the frequency of the output voltage ofVCO2008 can be changed during use ofultrasound vibration system1000 to respond to changes in a resonant frequency (e.g., the fundamental resonant frequency or a harmonic of the fundamental resonant frequency) ofacoustic horn assembly3500 ofhand piece assembly3000. For example, an input voltage toVCO2008 can be changed during use so that the frequency of the output voltage ofVCO2008 remains substantially equal to the resonant frequency ofacoustic horn assembly3500, as discussed in more detail below.
• Memory2010 stores information (e.g., one or more operational parameters) that is used to operateultrasound vibration system1000.
• Hand piece assembly3000 includesmemory3014, a user interface3018, andsensors3020.
• In general,memory3014 stores information (e.g., one or moreoperational parameters3016 for hand piece assembly3000) that is used to operateultrasound vibration system1000. Generally, the information stored inmemory3014 can be user modifiable or non-user modifiable. In some embodiments, some of the information (e.g., one or more of the operational parameters3016) stored inmemory3014 can be user modifiable, and some of the other information (e.g., one or more of the other operational parameters3016) stored inmemory3014 can be non-user modifiable. Non-user modifiable information can, for example, be stored in a write-protected portion (e.g., a erasable programmable read-only memory (EPROM) portion) ofmemory3014 such that, after this information is initially programmed forhand piece assembly3000, it can not be changed by an operator. As an example, in some embodiments, one or more of the operational parameters3016 (e.g., maximum activation period ofhand piece assembly3000, maximum post-activation use period ofhand piece assembly3000, maximum operational temperature foracoustic horn assembly3500, maximum operational temperature for wire4000) can be pre-programmed intomemory3014 prior to distributinghand piece assembly3000 for use (e.g., during manufacture and/or assembly of hand piece assembly3000).
• Examples ofoperational parameters3016 include an output voltage ofVCO2008, a current inhand piece assembly3000, a temperature of one or more components ofhand piece assembly3000, the maximum activation period ofhand piece assembly3000, the maximum post-activation use period ofhand piece assembly3000, a voltage to be applied toVCO2008, the resonant frequency of acoustic horn assembly3500 (e.g., as determined during the manufacture ofacoustic horn assembly3500, or as determined during the use of system1000), the resonant frequency of wire4000 (e.g., as determined during the manufacture ofwire4000, or as determined during the use of system1000), a temperature ofwire4000, identification information (e.g., forhand piece assembly3000,wire4000, and/or power supply2000), and a medical procedure to be performed with system1000 (e.g., ablating occlusions, removing plaque, removing bone cement, treating gynecological tissue, debulking prostate, treating urolithiasis, reinforcing bone, cleaning a vascular access device, treating deep vein thrombosis (DVT), treating peripheral arterial disease, and treating chronic total occlusions, phacoemulsification and/or treating coronary thrombosis lesions).
• User interface3018 can display information that may be useful for the operator during use ofsystem1000. Examples of such information include one or moreoperational parameters3016, one or more messages (see discussion below), or a combination thereof.
• Sensors3020 are generally used to monitor one or more of the operational parameters3016 (e.g., voltage, current, temperature, stress, strain) of hand piece assembly3000 (e.g., ofacoustic horn assembly3500 of hand piece assembly3000) and/orwire4000 during operation ofultrasound vibration system1000.Sensors3020 provide information topower supply2000 viacable2012, and, in response,power supply2000 can modify the operation of hand piece assembly3000 (e.g., by increasing the frequency of the output voltage ofVCO2008, by decreasing the frequency of the output voltage of VCO2008). Alternatively or additionally, one or more ofoperational parameters3016 can be monitored bypower supply2000. In some embodiments, for example, the voltage and current inhand piece assembly3000 are monitored bypower supply2000 while the temperature of hand piece assembly3000 (e.g., air temperature within hand piece assembly3000) is monitored bysensor3020 inhand piece assembly3000.
• FIG. 17 is a flow chart of an exemplary initialization and activation/operation process7000 forsystem1000.Operational parameters3016 are stored inmemory3014 of hand piece assembly3000 (7010).Hand piece assembly3000 is connected to power supply2000 (7020), and one or more of theoperational parameters3016 are transferred frommemory3014 to memory2010 (7030). Based on the operational parameter(s)3016 transferred tomemory2010,power supply2000 configures the operational parameter(s) (e.g., the amplitude of the output voltage of VCO2008) for initializing system1000 (7040).Operational parameters3016 can also include a frequency range used to sweep the output frequency ofVCO2008 to determine a resonant frequency ofacoustic horn assembly3500. Based onoperational parameters3016, an initial frequency sweep and tuning procedure is performed to configure the frequency of the output voltage ofVCO2008 for initializingsystem1000. After initializingsystem1000,power supply2000 generates a voltage signal that is transferred tohand piece assembly3000 to activate and/or operate hand piece assembly3000 (7050).
• Acoustic horn assembly3500 can be designed to vibrate in a longitudinal vibration mode.Acoustic horn assembly3500 can vibrationally resonate at its fundamental resonant frequency and at harmonics of its fundamental resonant frequency. Excitingacoustic horn assembly3500 at its resonant frequency (e.g., at its fundamental resonant frequency or at a harmonic of its fundamental resonant frequency) can increase the efficacy of converting an electrical input signal to vibration amplitude at the distal end ofacoustic horn assembly3500 where acoustic coupler1700 is located. The particular mode and harmonic frequency of excitation or vibration ofacoustic horn assembly3500 is generally determined by design and can be selected based on the intended use ofsystem1000. The particular mode and harmonic frequency of excitation or vibration ofacoustic horn assembly3500 can, for example, be selected based on the desired mode and frequency of the attachedwire4000. In some embodiments,system1000 is configured so that, during use,acoustic horn assembly3500 vibrates in a longitudinal mode at the second harmonic of its fundamental resonant frequency. However,acoustic horn assembly3500 can be designed to vibrate in other modes and/or at other harmonic frequencies, depending on the intended use ofsystem1000.
• In general, the resonant frequency (e.g., the fundamental resonant frequency or a harmonic of the fundamental resonant frequency) ofacoustic horn assembly3500 depends upon a number of parameters, some of which may be relatively constant during use ofsystem1000 and some of which may change a substantial amount during use ofsystem1000. Typically, the resonant frequency ofacoustic horn assembly3500 depends on one or more physical properties (e.g., length, cross sectional shape, cross sectional area) ofacoustic horn assembly3500 and/or one or more material properties (e.g., yield strength, material modulus) ofacoustic horn assembly3500. Generally, the resonant frequency ofacoustic horn assembly3500 also depends on the temperature ofacoustic horn assembly3500. As an example, as the temperature ofacoustic horn assembly3500 increases, the resonant frequency ofacoustic horn assembly3500 can decrease. As another example as the temperature ofacoustic horn assembly3500 decreases, the resonant frequency ofacoustic horn assembly3500 can increase. Thus, it is generally desirable forpower supply2000 to be capable of modifying the frequency of the output voltage ofVCO2008 tohand piece assembly3000 so that, as the resonant frequency ofacoustic horn assembly3500 changes, the frequency of the output voltage ofVCO2008 also changes to be at about the same frequency as (e.g., identical to) the resonant frequency ofacoustic horn assembly3500.
• In some embodiments, the resonant frequency ofacoustic horn assembly3500 ranges from about ten kHz to about 80 kHz (e.g., about 20 kHz to about 60 kHz, about 40 kHz to about 60 kHz, about 40 kHz).
• Wire4000 can be designed to vibrate in a longitudinal vibration mode.Wire4000 can vibrate at its resonant frequency (e.g., at its fundamental resonant frequency or at a harmonic of its fundamental resonant frequency) or at frequencies other than its resonant frequency. The resonant frequency ofwire4000 generally depends upon a number of parameters, some of which may be relatively constant during use ofsystem1000 and some of which may change a substantial amount during use ofsystem1000. Typically, the resonant frequency ofwire4000 depends on one or more physical properties (e.g., length, cross sectional shape, cross sectional area) ofwire4000 and/or one or more material properties (e.g., yield strength, material modulus) ofwire4000. Generally, the resonant frequency ofwire4000 also depends on the temperature ofwire4000 and/or the mechanical loading of wire4000 (e.g., the degree to whichwire4000 is bent). As an example, as the temperature ofwire4000 increases, the resonant frequency ofwire4000 can make a corresponding change. As another example as the temperature ofwire4000 decreases, the resonant frequency ofwire4000 can make a corresponding change.
• In certain embodiments, the longitudinal resonant frequency (e.g., the fundamental longitudinal resonant frequency or a harmonic of the fundamental longitudinal resonant frequency) ofacoustic horn assembly3500 differs from the longitudinal resonant frequency (e.g., the fundamental longitudinal resonant frequency or a harmonic of the fundamental longitudinal resonant frequency) ofwire4000. The longitudinal resonant frequency ofacoustic horn assembly3500 can, for example, differ from the nearest longitudinal resonant frequency ofwire4000 by about one kHz to about six kHz (e.g., about three kHz).Wire4000 andacoustic horn assembly3500 can, for example, be designed such that their respective longitudinal resonant frequencies differ from one another throughout use ofsystem1000. Maintaining a difference between the longitudinal resonant frequencies ofwire4000 andacoustic horn assembly3500 can helppower supply2000 to lock onto the longitudinal resonant frequency ofacoustic horn assembly3500 during use. The difference between the longitudinal resonant frequencies ofwire4000 andacoustic horn assembly3500 can, for example, help to provide a measurable phase difference between the voltage and current delivered toacoustic horn assembly3500 bypower supply2000 to helppower supply2000 lock onto the longitudinal resonant frequency ofacoustic horn assembly3500 during use.
• In certain embodiments,ultrasound horn assembly3500 has a longitudinal fundamental resonant frequency of about 20 kHz andwire4000 has a fundamental resonant frequency of about 2 kHz. In such embodiments, during use,ultrasound horn assembly3500 can be excited at 40 kHz, which is the second harmonic of its fundamental longitudinal resonant frequency. The vibration ofacoustic horn assembly3500 can causewire4000 to be excited or vibrated at 40 kHz. In some embodiments this is a frequency that lies between the ninth and tenth harmonics of the fundamental longitudinal resonant frequency ofwire4000. This frequency can alternatively fall between the 19^thand 20^thor 24^thand 25^th, harmonics of the fundamental longitudinal resonant frequency ofwire4000. Becausewire4000 is excited at a frequency between harmonics of its longitudinal resonant frequency,wire4000 does not vibrate at its resonant frequency.
• FIG. 18 is a flow chart of anexemplary process8000 for modifying the vibrational frequency ofacoustic horn assembly3500 as the resonant frequency ofacoustic horn assembly3500 changes.Power supply2000 initially determines the resonant frequency ofacoustic horn assembly3500, andpower supply2000 setsVCO2008 to generate an output voltage at a frequency such thatacoustic horn assembly3500 vibrates at a frequency that is about the same as (e.g., identical to) the resonant frequency of acoustic horn assembly3500 (8010). Asultrasound vibration system1000 is being used,power supply2000 determines if the resonant frequency ofacoustic horn assembly3500 has changed (8020). If the resonant frequency ofacoustic horn assembly3500 has not changed,power supply2000 continues to supply the same input voltage toVCO2008, causingVCO2008 to provide the same output voltage (e.g., a voltage having the same frequency) to acoustic horn assembly3500 (8030). If the resonant frequency ofacoustic horn assembly3500 has changed,power supply2000 adjusts the input voltage toVCO2008, changing the frequency of the output voltage ofVCO2008 such thatacoustic horn assembly3500 vibrates at a frequency that is about the same as (e.g., identical to) the new resonant frequency of acoustic horn assembly3500 (8040). As an example, in some embodiments in which the resonant frequency ofacoustic horn assembly3500 decreases during use ofsystem1000,power supply2000 can decrease the frequency of the output voltage ofVCO2008. As another example, in certain embodiments in which the resonant frequency ofacoustic horn assembly3500 increases during use ofsystem1000,power supply2000 can increase the frequency of the output voltage ofVCO2008.
• In general,power supply2000 can determine the resonant frequency ofacoustic horn assembly3500 using any desired method or combination of methods. In some embodiments,power supply2000 determines the resonant frequency ofacoustic horn assembly3500 based on the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500. Typically,power supply2000 determines the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500 via one or more current and voltage sensing devices.
• FIG. 19 shows a graph of avoltage signal9000aand a current signal9010awhere aphase difference9050 between these signals is non-zero, andFIG. 20 shows a graph of avoltage signal9000 and acurrent signal9010 where the phase difference between these signals is zero. InFIG. 19,voltage signal9000ahas aperiod9020a, amaximum value9030a, and aminimum value9040a, and current signal9010bhas aperiod9020b, amaximum value9030b, and aminimum value9040b. InFIG. 20, bothvoltage signal9000 andcurrent signal9010 have aperiod9020, amaximum value9030 and aminimum value9040.
• During use ofsystem1000,power supply2000 monitors both the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500 to determine the size of the phase difference between these signals. If the phase difference is zero,power supply2000 does not change the frequency of the output voltage ofVCO2008. However, if the phase difference is non-zero,power supply2000 changes the frequency of the output voltage ofVCO2008 so thatacoustic horn assembly3500 vibrates at a frequency that is about the same as (e.g., identical to) the resonant frequency ofacoustic horn assembly3500.
• FIG. 21 shows a block diagram of anexemplary control unit10001 designed to monitor the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500, and to modify the frequency of the output voltage ofVCO2008 so that, during use ofsystem1000, the vibrational frequency ofacoustic horn assembly3500 can be adjusted to be about the same as (e.g., identical to) the resonant frequency ofacoustic horn assembly3500.
• Control unit10001 includes ananalog control loop10000 and adigital control loop10010.Analog control loop10000 produces avoltage10060 that is based on the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500.Voltage10060 acts as an input voltage toVCO2008. Similarly,digital control loop10010 produces avoltage10070 that is based on the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500, andvoltage10070 acts as an input tovoltage VCO2008. By providing respective input voltages toVCO2008,analog control loop10000 anddigital control loop10010 determine the frequency of the output voltage ofVCO2008.
• Voltage10060 has a maximum range that is predetermined (e.g., set in memory) based on the expected range for the resonant frequency ofacoustic horn assembly3500 during use ofsystem1000, andvoltage10070 has a maximum range that is predetermined (e.g., set in memory) based on the expected range for the resonant frequency ofacoustic horn assembly3500 during use ofsystem1000. As a result, the maximum amount by whichanalog control loop10000 can adjust the frequency of the output voltage ofVCO2008 is predetermined, and the maximum amount by whichdigital control loop10010 can adjust the frequency of the output voltage ofVCO2008 is predetermined. In general, the maximum range ofvoltage10070 is greater than the maximum range ofvoltage10060. With this arrangement,digital control loop10010 sets a center frequency for the output voltage ofVCO2008, andanalog loop10000 then dynamically implements deviations in the frequency of the output voltage ofVCO2008 about this center frequency (e.g., within about 200 Hz of the center frequency, within about 100 Hz of the center frequency, within about 50 Hz of the center frequency, within about 10 Hz of the center frequency) to maintain a desired phase difference (e.g., about zero phase difference) between the current inhand piece assembly3000 and the voltage inhand piece assembly3000.
• Analog control loop10000 establishes the value ofvoltage10060 as follows. A voltagecurrent phase detector10040 is placed in electrical communication withhand piece assembly3000, andphase detector10040 determines the phase difference between the voltage applied toacoustic horn assembly3500 and the resulting current inacoustic horn assembly3500.Phase detector10040 provides to error integrator10050 a signal that corresponds to the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500.Error integrator10050 producesvoltage10060 based on the signal received fromphase detector10040. Generally, the magnitude ofvoltage10060 is proportional to the magnitude of the phase difference between the current inacoustic horn assembly3500 and the voltage inacoustic horn assembly3500. In other words, if the phase difference is relatively small amount, the magnitude ofvoltage10060 is usually relatively small, and, if the phase difference is relatively large, the magnitude ofvoltage10060 is usually relatively large. In general,integrator10050 is biased such thaterror integrator10050changes voltage10060 only when the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500 is outside a predetermined range. For example,phase error integrator10050 can be configured to changevoltage10060 only when the absolute value of the phase difference between the voltage inhand piece assembly3000 and the current inhand piece assembly3000 is greater than about 5° (e.g., greater than about 10°, greater than about 15°, greater than about 20°). Typically, if the resonant frequency ofacoustic horn assembly3500 decreases,error integrator10050 changes the value ofvoltage10060 to decrease the frequency of the output voltage ofVCO2008, and, if the resonant frequency ofacoustic horn assembly3500 increases,error integrator10050changes voltage10060 to increase the frequency of the output voltage ofVCO2008. In general,error integrator10050 can use any appropriate method to producevoltage10060 based on the signal received fromphase detector10040. As an example, in some embodiments,error integrator10050 can include a look-up table that informserror integrator10050 of the appropriate value forvoltage10060 based on thesignal error integrator10050 receives fromphase detector10040.
• Digital control loop10010 establishes the value ofvoltage10070 as follows. During initialization ofsystem1000, the signal produced byphase detector10040 is the input signal formicrocontroller10020, and during operation ofsystem1000 the signal produced byerror integrator10050 is the input signal formicrocontroller10020. Based on the input signal it receives,microcontroller10020 sends a digital signal to analog toDAC10030.DAC10030 converts the digital signal it receives frommicrocontroller10020 to an analog signal, which isvoltage10070. Thus,microcontroller10020 uses the signal it receives fromphase detector10040, which corresponds to the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500, to determine the signal it should send toDAC10030 so thatvoltage10070 is changed in a manner that achieves the desired corresponding change in the frequency of the output voltage ofVCO2008.Microcontroller10020 can do this, for example, based on the maximum range of the change in the frequency of the output voltage ofVCO2008 thatvoltage10070 can make. Typically,microcontroller10020 sends a signal toDAC10030 so thatDAC10030changes voltage10070 in the appropriate direction (e.g., decreasingvoltage10070 if the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500 is negative, increasingvoltage10070 if the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500 is positive) and by an absolute value that is proportional to the magnitude of the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500.
• FIG. 22 shows aprocess11000 for determining the initial center frequency for the output voltage ofVCO2008.Power supply2000 disables analog control loop10000 (11010). This causesvoltage10060 to be zero volts, and so the frequency of the output voltage ofVCO2008 is determined byoutput voltage10070 ofdigital control loop10010. Whileanalog control loop10010 is disabled, the output signal fromphase detector10040 is the input signal formicrocontroller10020. The amplitude ofvoltage10070 is swept through its maximum range (11020), causing the frequency ofvoltage10080 to be swept through its maximum frequency range. As the amplitude ofvoltage10070 is swept through its maximum range,phase detector10040 monitors the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500, and provides this information tomicrocontroller10020.Microcontroller10020 then determines the frequency for the output voltage ofVCO2008 that results in the smallest phase difference and will causeacoustic horn assembly3500 to vibrate at a frequency that is about the same as (e.g., identical to) the resonant frequency of acoustic horn assembly3500 (11030).Microcontroller10020 then provides the appropriate digital signal toDAC10030, andDAC10030 converts this signal to an analog signal (voltage10070) so that the frequency of the output voltage ofVCO2008 results inacoustic horn assembly3500 vibrating at a frequency that is about the same as (e.g., identical to) the resonant frequency of acoustic horn assembly3500 (11040).Power supply2000 subsequently enables analog control loop10000 (11050), anddigital control loop10010 andanalog control loop10000 are used to dynamically adjust the output frequency ofVCO2008 via the amplitude ofvoltages10060 and10070 applied toVCO2008, as discussed above.
• During operation ofsystem1000, the output of error integrator10050 (i.e., voltage10060) is the input todigital control loop10010. As a result, the output of analog control loop10000 (i.e., voltage10060) determines the output of digital control loop10010 (i.e., voltage10070). Thus,digital control loop10010 dynamically changes the center frequency of the output voltage of VCO.2008 based on voltage10600, which, in turn, is based on the phase difference between the voltage inacoustic horn assembly3500 and the current inacoustic horn assembly3500.
• As noted above, there is a predetermined maximum range of values forvoltage10060. This maximum range of values forvoltage10060 can be divided into multiple regions so that the amount by whichvoltage10060 causesdigital control loop10010 to change the frequency of the output voltage ofVCO2008 depends on the region in whichvoltage10060 is located. For example,FIG. 23 shows amaximum range12000 of values forvoltage10060.Range12000 is divided intoregions12010,12020,12030,1204012050. Whenvoltage10060 is inregion12030,voltage10060 causes relatively little or no change in the frequency of the output voltage ofVCO2008. Whenvoltage10060 is inregion12010,voltage10060 causes its maximum positive change in the frequency of the output voltage ofVCO2008, and, whenvoltage10060 is inregion12050,voltage10060 causes its maximum negative change in the frequency of the output voltage ofVCO2008. Whenvoltage10060 is inregion12020, voltage10600 causes a positive change in the frequency of the output voltage ofVCO2008 that is greater than that caused whenvoltage10060 is inregion12030 but less than whenvoltage10060 is inregion12010. Whenvoltage10060 is inregion12040,voltage10060 causes a negative change in the frequency of the output voltage ofVCO2008 that is greater than that caused whenvoltage10060 is inregion12030 but less than whenvoltage10060 is inregion12050.
• In general, the magnitude ofregions12010,12020,12030,12040,12050 can be selected as desired. For example, in some embodiments, these regions can have the following magnitudes.Region12030 can be centered at the middle ofrange12000, andregion12030 can occupy at most about 70% (e.g., at most about 60%, at most about 50%, at most about 40%) ofrange12000.Region12020 can have a minimum value corresponding to the maximum value ofregion12030, and can occupy at most about 30% (e.g., at most about 25%, at most about 20%, at most about 15%) ofrange12000.Region12040 can have a maximum value corresponding to the minimum value ofregion12030, and can occupy at most about 30% (e.g., at most about 25%, at most about 20%, at most about 15%) ofrange12000.Region12010 can have a minimum value corresponding to the maximum value ofregion12020 and a maximum value corresponding to the maximum value ofvoltage10060.Region12010 can occupy at most about 10% (e.g., at most about 7%, at most about 5%, at most about 3%) ofrange12000.Region12050 can have a maximum value corresponding to the minimum value ofregion12040 and a minimum value corresponding to the minimum value ofvoltage10060.Region12050 can occupy at most about 10% (e.g., at most about 7%, at most about 5%, at most about 3%) ofrange12000.
• FIG. 24 shows a flow chart of anexemplary process13000 for modifying the center frequency of the output voltage ofVCO2008 based on the magnitude ofvoltage10060, usingregions12010,12020,12030,12040 and12050 ofmaximum range12000 forvoltage10060. First,voltage10060 is input to microcontroller10020 (13010).Microcontroller10020 determines the region in whichvoltage10060 is located (13020). Ifvoltage10060 is inregion12030,microcontroller10020 sends a signal toDAC10030 so thatvoltage10070 does not change, resulting in no change in the center frequency of the output voltage of VCO2008 (13030). Ifvoltage10060 is inregion12020 orregion12040,microcontroller10020 sends a signal toDAC10030 so thatvoltage10070 changes but by a relatively small amount (13040). This causes the center frequency of the output voltage ofVCO2008 to change but by a relatively small amount, corresponding to a relatively slow change (e.g., as measured in Hz per second) in the center frequency of the output voltage ofVCO2008. For example,voltage10070 can be adjusted in relatively small frequency increments such that the change in the center frequency of the output voltage ofVCO2008 is relatively slow. Ifvoltage10060 is inregion12010 orregion12050,microcontroller10020 sends a signal toDAC10030 so thatvoltage10070 changes by a relatively large amount (13050). This causes the center frequency of the output voltage ofVCO2008 to change by a relatively large amount, corresponding to a relatively fast change (e.g., as measured in Hz per second) in the center frequency of the output voltage ofVCO2008. For example,voltage10070 can be adjusted in relatively large frequency increments such that the change in center frequency of theoutput voltage VCO2008 is relatively fast.
• In general, for a given region ofvoltage10060, the amount by whichvoltage10070 changes is based on the desired change in the frequency of the output voltage ofVCO2008 for the region ofvoltage10060, bearing in mind that, becausevoltage10070 has a maximum range of values, there is also a corresponding maximum range of change in the frequency of the output voltage ofVCO2008 that can be caused byvoltage10070. As an example, ifvoltage10060 is inregion12010 or12050, thenmicrocontroller10020 can send a signal toDAC10030 so thatvoltage10070 results in a change in the frequency of the output voltage ofVCO2008 that is from about 25% to about 50% of the maximum range of change in the frequency of the output voltage ofVCO2008 that can be caused byvoltage10070. As another example, ifvoltage10060 is inregion12020 or12040, thenmicrocontroller10020 can send a signal toDAC10030 so thatvoltage10070 results in a change in the frequency of the output voltage ofVCO2008 that is from at most about 1% (e.g., about 0.5) of the maximum range of change in the frequency of the output voltage ofVCO2008 that can be caused byvoltage10070.
• In some embodiments, if certain conditions are satisfied, it may be desirable to be able to preventhand piece assembly3000 from being initially enabled and/or to disablehand piece assembly3000 after it has been initially enabled. As an example, in embodiments in whichhand piece assembly3000 has a maximum time period for which it can be activated (maximum activation period),hand piece assembly3000 can be disabled if it has met or exceeded this time period. As another example, in embodiments in whichhand piece assembly3000 has a maximum period time after activation that it can be used (maximum post-activation use period),hand piece assembly3000 can be disabled if it has met or exceeded this time period. As a further example, in embodiments in whichacoustic horn assembly3500 has a temperature that it should not exceed during use ofsystem1000,hand piece assembly3000 can be disabled ifacoustic horn assembly3500 is at or above this temperature. As another example, in embodiments in whichwire4000 has a temperature that it should not exceed during use ofsystem1000,hand piece assembly3000 can be disabled ifwire4000 is at or above this temperature. As an additional example, in embodiments in which there is a maximum frequency difference that should exist between the vibrational frequency ofacoustic horn assembly3500 and the resonant frequency ofacoustic horn assembly3500,hand piece assembly3000 can be disabled if this maximum frequency difference is met or exceeded. In some embodiments, if it is determined thathand piece assembly3000 should be disabled,hand piece assembly3000 is permanently disabled. In certain embodiments, if it is determined thathand piece assembly3000 should be disabled,hand piece assembly3000 is temporarily disabled.
• FIG. 25 shows anexemplary process15000 for enablinghand piece assembly3000 and subsequently disablinghand piece assembly3000 wherehand piece assembly3000 has both a maximum activation period and a maximum post-activation use period. The value of the maximum activation period and the value of the maximum post-activation are stored inmemory3014 in hand piece assembly3000 (15010). In general, the maximum activation period and the maximum post-activation use period can be selected as desired. In some embodiments, the maximum activation period ofhand piece assembly3000 is at most about 10 hours (e.g., at most about five hours, at most about two hours, at most about one hour, at most about 30 minutes, at most about 25 minutes, at most about 20 minutes, at most about 15 minutes, at most about 10 minutes, at most about five minutes). In certain embodiments, the maximum post-activation use period ofhand piece assembly3000 is at most about one week (e.g., at most about five days, at most about two days, at most about one day, at most about 12 hours).Hand piece assembly3000 is connected to power supply2000 (15020), andsystem1000 determines ifhand piece assembly3000 has been used previously (15030). Ifhand piece assembly3000 has not been used before (i.e.,hand piece assembly3000 is being activated for the first time),system1000 stores in memory3014 a value indicating the time the hand piece assembly is first activated (15040).System1000 then compares the amount of time thathand piece assembly3000 has been activated to the maximum activation period of hand piece assembly3000 (15050). If the amount of time thathand piece assembly3000 has been activated is equal to or greater than the maximum activation period ofhand piece assembly3000,system1000 preventshand piece assembly3000 from being enabled (15060). If the amount of time thathand piece assembly3000 has been activated is less than the maximum activation period ofhand piece assembly3000,system1000 compares the period of time sincehand piece assembly3000 was activated to the maximum post-use activation period of hand piece assembly3000 (15070). If the period of time sincehand piece assembly3000 was activated is equal to or greater than the maximum post-activation use period ofhand piece assembly3000,system1000 prevents hand piece assembly3000 (2210) from being enabled (15060). If the period of time sincehand piece assembly3000 was first activated is less than the maximum post-activation use period ofhand piece assembly3000,system1000 enables operation of hand piece assembly3000 (15080).System1000 goes through this loop at predetermined time intervals so that, afterhand piece assembly3000 is enabled,hand piece assembly3000 can be disabled if appropriate. In certain embodiments, the predetermined time interval is at most about five seconds (e.g., at most about four seconds, at most about three seconds, at most about two seconds, at most about one second, at most about 0.5 second, at most about 0.2 second, at most about 0.1 second).
• In some embodiments,system1000 can provide an indication, such as an audio indication (e.g., sounding an alarm) and/or a visual indication (e.g., an LED message on hand piece assembly3000), to a user a given parameter is approaching a critical value. As an example,system1000 can provide an indication to a user asacoustic horn assembly3500 is approaching its maximum use temperature. As an additional example,system1000 can provide an indication to a user aswire4000 is approaching its maximum use temperature. As another example,system1000 can provide an indication to a user ashand piece assembly3000 is approaching its maximum activation period. As a further example,system1000 can provide an indication to a user ashand piece assembly3000 is approaching its maximum post-activation use period. As an additional example,system1000 can provide an indication to a user as the difference between the vibrational frequency ofacoustic horn assembly3500 and the resonant frequency ofacoustic horn assembly3500 is approaching its maximum value.
• While certain embodiments have been described, other embodiments are possible.
• As an example, while embodiments have been described in whichpower switch3135 is a touch switch, more generally,power switch3135 can be any switch that can move between a first state (e.g.,power supply2000 on) and a second state (e.g.,power supply2000 off). In some embodiments,power switch3135 is a slide switch for which displacing the switch to a first position places the switch in the first state and displacing the switch to a second position places the switch in the second state.
• As another example, in someembodiments system1000 can include additional features. In some embodiments,system1000 can include a catheter that surroundswire4000. The catheter can, for example, allow a fluid (e.g., an irrigation fluid, a fluid containing a therapeutic agent, a cooling fluid) to flow betweenwire4000 and the catheter, and/or the catheter can assist insteering wire4000. In embodiments in whichsystem1000 includes a catheter,system1000 may include additional equipment to monitor fluid flow through the catheter. For example,system1000 can include a bubble detector that can detect bubbles in the fluid as it passes through the catheter. The bubble detector can include, for example, an electromagnetic energy emitter (e.g., IR emitter, UV emitter, visible light emitter) and a corresponding detector configured to detect the presence of bubbles in the fluid passing through the catheter. Alternatively or additionally,system1000 can include a flow meter to regulate the flow rate of fluid through the catheter. Regulation of the flow rate of the fluid can, for example, help to regulate the rate at whichwire4000 is cooled during use. In certain embodiments, one or more portions ofsystem1000 that will be disposed within a subject during use (e.g., one or more regions of wire4000) can include a radiopaque material. In certain embodiments, a radiopaque material be disposed at or near the distal end ofwire4000 so that the location of the distal end ofwire4000 can be located within a patient using fluoroscopy. In some embodiments, the radiopaque material can be in the shape of bands disposed on (e.g., painted on, swaged on)wire4000. In certain embodiments, the radiopaque material can be incorporated into (e.g., alloyed with) the material that formswire4000. Examples of radiopaque materials include tungsten, tantalum, rhenium, iridium, silver, gold, bismuth, platinum, molybdenum and alloys thereof. The radiopaque material can, for example, assist in determining the location ofwire4000 within a subject. Examples of the foregoing features are disclosed, for example, in Rabiner et al., U.S. Pat. No. 6,802,835; Rabiner et al. U.S. Pat. No. 6,733,451; and Hare et al., U.S. Pat. No. 6,730,048.
• As a further example, while embodiments have been disclosed in which two piezoelectric transducers are used, in certain embodiments a different number (e.g., one, three, four, five, six, seven, eight, nine, 10) of piezoelectric transducers can be used.
• As still another example, while the piezoelectric transducers have been described as piezoceramic rings, other types of piezoelectric transducers can be used. Moreover, while embodiments have been disclosed in which piezoelectric transducers are used, other types of transducers may be used. Examples of transducers include magnetostrictive transducers, pneumatic transducers and hydraulic transducers. In some embodiments, combinations of types of transducers can be used.
• As an additional example, while embodiments have been described in whichwire4000 is metallurgically bonded with an acoustic coupler, incertain embodiments wire4000 and the acoustic coupler can be coupled using other techniques. For example,wire4000 and the acoustic coupler can be coupled with a mechanical connection. In some embodiments, the acoustic coupler is crimped ontowire4000. For example, the acoustic coupler and wire can be mechanically joined by deforming a cylindrical portion of the coupler around an end region of the wire over a given length. Other mechanical connections are disclosed, for example, in Rabiner et al., U.S. Pat. No. 6,679,873; Ranucci et al., U.S. Pat. No. 6,695,782; and Hare et al., U.S. Patent Application 2003/0065263.
• As another example, while embodiments have been described in which the cross-sectional shape ofwire4000 is circular, other cross-sectional shapes may also be used. For example, the cross-sectional shape ofwire4000 can be triangular, elliptical, or rectangular. In some embodiments, different portions ofwire4000 have different cross-sectional shapes.
• As a further example, while embodiments have been disclosed wherewire4000 is formed of Ti-6Al-4V titanium, in certain embodiments,wire4000 can be formed of a different material. In general,wire4000 can be formed of any material capable of supporting ultrasonic vibrations. In some embodiments,wire4000 is formed of a material having a flexural stiffness of at least about 1×10⁷N/m (e.g., at least about 2.5×10⁷N/m, at least about 4×10⁷N/m) and/or at most about 10×10⁷N/m (e.g., at least about 8.5×10⁷N/m, at least about 7×10⁷N/m). Examples of materials from whichwire4000 can be made include metals (e.g., titanium, stainless steel) and alloys (e.g., titanium alloys other than annealed Ti-6Al-4V titanium, stainless steel alloys).
• As an additional example, while embodiments of an unbentwire4000 have been shown, it is to be understood that, in general, during the use ofsystem1000,wire4000 will be bent. In some embodiments, during use ofsystem1000,wire4000 may have one or more bends. In certain embodiments, when bent,wire4000 may take on a shape that is helical (along axis4015). In some embodiments,wire4000 may bend in multiple planes (e.g., as compared to axis4015).
• As another example, whilepower supply2000 has been described as includinginput device2006 to allow the user to program or modify certain operational parameters ofsystem1000, in some embodiments, power supply includes no such input device. In such embodiments, for example, the user can be prevented from programming or modifying any operational parameters of the system.
• As yet a further example, while embodiments have been described in which a multi-wire cable provides communication betweenpower supply2000 andhand piece assembly3000, other communication devices can be used. In some embodiments, a one-wire cable can provide the communication path betweenpower supply2000 andhand piece assembly3000. An exemplary one-wire cable is described in Dallas Semiconductor Data Sheet DS2436 and Dallas Semiconductor Data Sheet DS2480. In certain embodiments, a single wire of the one-wire cable can be used to transmit both power and information betweenpower supply2000 andhand piece assembly3000. In some embodiments, a wireless communication system can provide the communication path betweenpower supply2000 andhand piece assembly3000 while a wire provides the electrical current path to deliver power frompower supply2000 andhand piece assembly3000. Combinations of devices are also possible.
• As another example, in certain embodiments,hand piece assembly3000 can be labeled to indicate the procedure for whichhand piece assembly3000 is designed to be used. Exemplary labels include stickers applied to thehand piece assembly3000 and/or a package which includes thehand piece assembly3000, a label printed on a package which includes thehand piece assembly3000, a label printed on thehand piece assembly3000, an RFID tag included in thehand piece assembly3000, and an RFID tag included in the package which includes thehand piece assembly3000. The labels can include various information such as the procedure thehand piece assembly3000 is designed to be used for, the length ofwire4000, and/or an expiration date for thehand piece assembly3000. Such labeling can allow for quick and easy selection by a user, and/or can reduce the possibility that improper equipment will be used for a given procedure. In some embodiments, a labeled hand piece assembly can have the appropriate operational parameters stored in its memory so that the ultrasound vibration system operates in appropriate fashion for the given procedure.
• As a further example, while embodiments have been described in whichhand piece assembly3000 automatically transfersoperational parameters3016 topower supply2000 whenhand piece assembly3000 is connected topower supply2000, other methods for transferringoperational parameters3016 fromhand piece assembly3000 topower supply2000 are possible. For example, in some embodiments,power supply2000 detects a connection tohand piece assembly3000 andpower supply2000 sends a request tohand piece assembly3000 foroperational parameters3016.Hand piece assembly3000 receives the request and, in response, sends the requestedoperational parameters3016 topower supply2000.
• As an additional example, while embodiments have been described in whichmemory3014 stores one or moreoperational parameters3016, in someembodiments memory3014 can store one or more identifiers (e.g., character identifiers including letters and/or numbers) corresponding to a particular operational parameter or a particular set of operational parameters in addition to, or instead of, storing operational parameters. In such embodiments,hand piece assembly3000 can transfer the identifier(s) topower supply2000 upon connection ofhand piece assembly3000 topower supply2000.Power supply2000 can use the identifier(s), for example, to determine a set of operational parameters for activation and/or operation ofsystem1000. For example,power supply2000 can include a database or look-up table of operational parameters and associated identifiers which can be used to determine the correct set of one or more operational parameters based on the identifier(s) received frommemory3014. Storing one or more identifiers inmemory3014 can provide the advantage of reducing the size of the memory inhand piece assembly3000 compared to the size of a memory used to store multiple operational parameters. As an example, in some embodiments, the identifier(s) can indicate the length ofwire4000, and the identifier(s) can provide appropriate operational parameters forpower supply2000 to operatesystem1000 given the length ofwire4000. As another example, in certain embodiments, the identifier(s) can indicate a procedure to be performed withsystem1000, and the identifier(s) can provide appropriate operational parameters forpower supply2000 to operatesystem1000 given the procedure to be performed.
• As another example, while embodiments have been described in whichvoltage10060 is divided into five regions, in certainembodiments output voltage10060analog control loop10000 can be divided into fewer regions (e.g., two regions, three regions, four regions) or more regions (e.g., six regions, seven regions, eight regions, nine regions, 10 regions, 11, regions, 12 regions).
• As an additional example, while embodiments have been described in whichvoltage10070 is divided into six bins, incertain embodiments voltage10070 can be divided into fewer bins (e.g., two bins, three bins, four bins, five bins) or more regions (e.g., seven bins, eight bins, nine bins, 10 bins, 11, bins, 12 bins).
• As a further example, in some embodiments,hand piece assembly3000 can include an activation switch that an operator ofsystem1000 can depress to activatehand piece assembly3000. Examples of activation switches include buttons, touch screens and mechanical switches. In certain embodiments, when the user depresses the activation switch,hand piece assembly3000 can send a message topower supply2000 to activatehand piece assembly3000. Optionally,system1000 can be designed to include appropriate circuitry to confirm that the user has actually depressed the activation switch before activating hand piece assembly3000 (e.g., to confirm that the signal received bypower supply2000 was not an error).FIG. 26 shows aprocess17000 for confirming that an activation switch has been pressed prior to activatinghand piece assembly3000. In order to activatehand piece assembly3000, an operator presses the activation switch (17010). In response, a voltage level onhand piece assembly3000 is changed (17020). For example, a voltage level inhand piece assembly3000 can be changed from a system high voltage level to a system low voltage level (e.g., from 8V to 3.5V, from 5V to 0V).Hand piece assembly3000 also sends a serial communication topower supply2000 overcommunication line2012 in response to activation switch being pressed (17030).Power supply2000 determines if both the serial communication has been received and the voltage level inhand piece assembly3000 has dropped (17040). If both the serial communication has been received and the voltage level inhand piece assembly3000 has dropped,hand piece assembly3000 is enabled (17050). Otherwise,hand piece assembly3000 remains disabled (17040).
• While certain embodiments discussed above describeacoustic horn assembly3500 andwire4000 as being designed to vibrate longitudinally, other designs are possible. For example,acoustic horn assembly3500 and/orwire4000 can be designed to vibrate longitudinally, transversely, and/or torsionally.
• Other embodiments are in the claims.

Claims (28)

1. A method, comprising:

operating an ultrasound vibration element having proximal and distal ends so that:

the distal end of the ultrasound vibration element vibrates in a longitudinal direction of the distal end of the ultrasound vibration element; and

a portion of the ultrasound vibration element vibrates in a direction perpendicular to the longitudinal direction of the distal end of the ultrasound vibration element, the portion of the ultrasound vibration element being between the proximal and distal ends of the ultrasound vibration element; and

advancing the vibration element through an occlusion in a body vessel of a subject while the vibration element is being operated.

2. The method ofclaim 1, wherein the body vessel comprises a blood vessel.

3. The method ofclaim 2, further comprising disposing the distal end of the ultrasound vibration element in the occlusion in the blood vessel of the subject.

4. The method ofclaim 3, wherein the longitudinal vibration of the distal end of the ultrasound vibration element is used to advance the ultrasound vibration element through the occlusion in the blood vessel of the subject.

5. The method ofclaim 3, further comprising at least partially breaking up the occlusion in the blood vessel of the subject.

6. The method ofclaim 3, wherein the vibration of the portion of the ultrasound vibration element is used to at least partially ablate the occlusion in the blood vessel of the subject.

7. The method ofclaim 1, wherein the vibration element comprises a wire.

8. The method ofclaim 1, wherein operating the vibration element comprises delivering electrical energy to an assembly that is coupled to the vibration element, the assembly being configured to convert electrical energy to mechanical energy.

9. The method ofclaim 8, wherein the assembly comprises an acoustic horn.

10. The method ofclaim 1, wherein the method is used to treat a chronic total occlusion, to debulk the prostate, to treat gynecological tissue, to remove bone cement, or to perform phacoemulsification.

11. The method ofclaim 1, wherein the method is used to treat a condition selected from the group consisting of deep vein thrombosis, urolithiasis, and peripheral arterial disease.

12. A method, comprising:

vibrating a distal end of an ultrasound vibration element in a longitudinal direction, and vibrating a portion of the ultrasound vibration element proximal to the distal end in a direction perpendicular to the longitudinal direction, the distal end of the vibration element being disposed adjacent an occlusion in a body vessel; and

advancing the ultrasound vibration element through the occlusion while vibrating the distal end in the longitudinal direction.

13. The method ofclaim 12, wherein the body vessel comprises a blood vessel.

14. The method ofclaim 13, further comprising disposing the distal end of the ultrasound vibration element in the occlusion in the blood vessel of the subject.

15. The method ofclaim 14, wherein the longitudinal vibration of the distal end of the ultrasound vibration element is used to advance the ultrasound vibration element through the occlusion in the blood vessel of the subject.

16. The method ofclaim 14, further comprising at least partially breaking up the occlusion in the blood vessel of the subject.

17. The method ofclaim 14, wherein the vibration of the portion of the ultrasound vibration element proximal to the distal end is used to at least partially ablate the occlusion in the blood vessel of the subject.

18. The method ofclaim 12, wherein the vibration element comprises a wire.

19. The method ofclaim 12, wherein vibrating the distal end and the portion proximal to the distal end of the vibration element comprises delivering electrical energy to an assembly that is coupled to the vibration element, the assembly being configured to convert electrical energy to mechanical energy.

20. The method ofclaim 19, wherein the assembly comprises an acoustic horn.

21. A method, comprising advancing an ultrasound vibration element through an occlusion of a body vessel while vibrating a distal end of the ultrasound vibration element in a longitudinal direction.

22. The method ofclaim 21, further comprising vibrating a portion of the ultrasound vibration element proximal to the distal end in a direction perpendicular to the longitudinal direction.

23. The method ofclaim 21, wherein the body vessel comprises a blood vessel.

24. The method ofclaim 23, wherein the longitudinal vibration of the distal end of the ultrasound vibration element is used to advance the ultrasound vibration element through the occlusion in the blood vessel of the subject.

25. The method ofclaim 23, further comprising at least partially breaking up the occlusion in the blood vessel of the subject.

26. The method ofclaim 23, wherein the vibration of the portion of the ultrasound vibration element is used to at least partially ablate the occlusion in the blood vessel of the subject.

27. The method ofclaim 21, wherein the vibration element comprises a wire.

28. The method ofclaim 21, wherein vibrating the vibration element comprises delivering electrical energy to an assembly that is coupled to the vibration element, the assembly being configured to convert electrical energy to mechanical energy.

Images