U.S. patent application number 11/515810 was filed with the patent office on 2007-03-22 for ultrasound medical devices and related methods.
Invention is credited to Douglas Hutchison, Mark E. Schafer.
Application Number | 20070066978 11/515810 |
Document ID | / |
Family ID | 37667292 |
Filed Date | 2007-03-22 |
United States Patent
Application |
20070066978 |
Kind Code |
A1 |
Schafer; Mark E. ; et
al. |
March 22, 2007 |
Ultrasound medical devices and related methods
Abstract
Ultrasound medical devices and related methods are
described.
Inventors: |
Schafer; Mark E.; (Ambler,
PA) ; Hutchison; Douglas; (Winchester, MA) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Family ID: |
37667292 |
Appl. No.: |
11/515810 |
Filed: |
September 5, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60714456 |
Sep 6, 2005 |
|
|
|
Current U.S.
Class: |
606/128 |
Current CPC
Class: |
A61B 2017/00084
20130101; A61B 2017/00132 20130101; A61B 2017/00778 20130101; A61B
2017/0011 20130101; A61M 37/0092 20130101; A61B 2017/22001
20130101; A61B 90/98 20160201; A61B 2017/00119 20130101; A61B
17/22029 20130101; A61B 2017/00482 20130101; B06B 1/0238 20130101;
A61B 2017/00199 20130101; A61B 17/22012 20130101; A61B 2017/22015
20130101; A61B 2017/00017 20130101; A61B 5/02007 20130101; A61B
17/22004 20130101; A61B 2017/00477 20130101; A61B 90/90 20160201;
A61B 2017/00106 20130101; A61B 2090/0803 20160201; A61B 8/485
20130101; A61B 8/56 20130101; H03L 5/02 20130101; A61B 8/0833
20130101; A61B 8/12 20130101; A61B 2017/22018 20130101; H03L 7/10
20130101; A61B 2017/00123 20130101; B06B 1/0253 20130101; A61B
2017/22008 20130101; G10K 11/02 20130101 |
Class at
Publication: |
606/128 |
International
Class: |
A61B 17/22 20060101
A61B017/22 |
Claims
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 of claim 1, wherein the body vessel comprises a blood
vessel.
3. The method of claim 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 of claim 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 of claim 3, further comprising at least partially
breaking up the occlusion in the blood vessel of the subject.
6. The method of claim 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 of claim 1, wherein the vibration element comprises a
wire.
8. The method of claim 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 of claim 8, wherein the assembly comprises an
acoustic horn.
10. The method of claim 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 of claim 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 of claim 12, wherein the body vessel comprises a
blood vessel.
14. The method of claim 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 of claim 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 of claim 14, further comprising at least partially
breaking up the occlusion in the blood vessel of the subject.
17. The method of claim 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 of claim 12, wherein the vibration element comprises
a wire.
19. The method of claim 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 of claim 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 of claim 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 of claim 21, wherein the body vessel comprises a
blood vessel.
24. The method of claim 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 of claim 23, further comprising at least partially
breaking up the occlusion in the blood vessel of the subject.
26. The method of claim 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 of claim 21, wherein the vibration element comprises
a wire.
28. The method of claim 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.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] 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
[0002] This description relates to ultrasound medical devices and
related methods.
BACKGROUND
[0003] 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).
[0004] 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
[0005] 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.
[0006] 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.
[0007] 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.
[0008] Embodiments can include one or more of the following
features.
[0009] In some embodiments, the body vessel is a blood vessel.
[0010] 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.
[0011] 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.
[0012] In certain embodiments, the method further includes at least
partially breaking up the occlusion in the blood vessel of the
subject.
[0013] 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.
[0014] In certain embodiments, the vibration element includes a
wire.
[0015] 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.
[0016] In certain embodiments, the assembly includes an acoustic
horn.
[0017] 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.
[0018] In certain embodiments, the method is used to treat deep
vein thrombosis, urolithiasis, and/or peripheral arterial
disease.
[0019] Embodiments can include one or more of the following
advantages.
[0020] Generally, the systems can be designed for relatively safe,
easy and effective use.
[0021] 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.
[0022] 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.
[0023] Other aspects, features, and advantages will be apparent
from the description and claims.
DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a schematic drawing of an ultrasound vibration
system.
[0025] FIG. 2 is a schematic diagram of a portion of an ultrasound
vibration system when activated.
[0026] FIGS. 3 through 6 are schematic drawings of a method of
using an ultrasound vibration system to treat an occluded blood
vessel.
[0027] FIGS. 7A and 7B are schematic perspective and top views,
respectively, of a hand piece assembly.
[0028] FIG. 8 is a sectional view of the hand piece assembly of
FIGS. 7A and 7B.
[0029] FIGS. 9A to 9D are perspective, alternative perspective,
side and sectional views, respectively, of an acoustic coupler.
[0030] FIGS. 10A to 10C are perspective, alternative perspective,
and cross sectional views, respectively, of another acoustic
coupler.
[0031] FIGS. 11A to 11C are schematic perspective, side, and
sectional views, respectively, of a portion of hand piece
assembly.
[0032] FIGS. 12A to 12C are schematic perspective, side, and
sectional views, respectively, of a portion of another hand piece
assembly.
[0033] FIGS. 13A and 13B are schematic side and end views,
respectively, of a wire.
[0034] FIG. 14 is a schematic view of an acoustic horn as modeled
with a finite element analysis.
[0035] FIGS. 15A to 15C 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 of FIG. 14 and achieved using finite element
analysis.
[0036] FIG. 16 is a schematic drawing of a portion of an ultrasound
vibration system.
[0037] FIG. 17 is a flow chart of an initialization and
activation/operation process for an ultrasound vibration
system.
[0038] 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.
[0039] FIG. 19 is a graph of a voltage signal and a current signal
where the phase difference between the signals is non-zero.
[0040] FIG. 20 is a graph of a voltage signal and a current signal
where the phase difference between the signals is zero.
[0041] 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.
[0042] FIG. 22 shows a process for determining the initial center
frequency for the output voltage of a voltage controlled
oscillator.
[0043] FIG. 23 shows a maximum range of values for an input voltage
for a voltage controlled oscillator.
[0044] FIG. 24 is a flow chart of a process for modifying the
center frequency of the output voltage of a voltage controlled
oscillator.
[0045] FIG. 25 shows an exemplary process for enabling/disabling a
hand piece assembly.
[0046] FIG. 26 shows a process for confirming activation of a hand
piece assembly.
[0047] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0048] FIG. 1 shows an ultrasound vibration system 1000 that
includes a power supply 2000, a hand piece assembly 3000 and an
Ti-6Al-4V titanium wire 4000. Power supply 2000 is in electrical
communication with hand piece assembly 3000, and hand piece
assembly 3000 is mechanically coupled with wire 4000. As explained
in detail below, power supply 2000 provides electrical energy
(e.g., an oscillating voltage) to hand piece assembly 3000, and
hand piece assembly 3000 converts this electrical energy to
mechanical energy in the form of ultrasonic vibrations in an
acoustic horn assembly 3500 (shown in FIG. 8) of hand piece
assembly 3000 (e.g., ultrasonic vibrations at a resonant frequency
of acoustic horn assembly 3500 of hand piece assembly 3000). The
ultrasonic vibrations within acoustic horn assembly 3500 of hand
piece assembly 3000 are transferred to wire 4000. Without wishing
to be bound by theory, it is believed that the ultrasonic
vibrations of wire 4000 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 of wire 4000 on the biological material can involve wire
4000 directly contacting the biological material as wire 4000
vibrates, and/or wire 4000 creating ultrasonic vibrations in body
fluid (e.g., blood) adjacent wire 4000 that are directly
communicated to the biological material. It is believed that an
indirect effect of wire 4000 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.
[0049] FIG. 2 shows a representation of wire 4000 while vibrating.
The vibrations in wire 4000 include nodes 4050 and anti-nodes 4060.
Nodes 4050 are locations of minimum amplitude vibration of wire
4000, and anti-nodes 4060 are locations of maximum amplitude
vibration of wire 4000.
[0050] The type of vibrational modes in wire 4000 are generally
selected based on the intended use of ultrasound vibration system
1000 (e.g., the condition to be treated with system 1000). In
general, the vibrations of wire 4000 can be transverse modes (modes
for which the vibration is perpendicular to the longitudinal axis
of wire 4000), longitudinal modes (modes for which the vibration is
parallel to the longitudinal axis of wire 4000), or combinations
thereof. FIG. 2 shows an embodiment where wire 4000 is undergoing
transverse vibration. In some embodiments, however, one or more
portions of wire 4000 can undergo transverse vibration while one or
more other portions of wire 4000 undergo longitudinal vibration.
For example, when breaking up an occlusion in a blood vessel, it
may be desirable for the distal end of wire 4000 to undergo
longitudinal vibration (to allow wire 4000 to penetrate into the
occlusion) and for a more proximal portion of wire 4000 (e.g., the
portion of wire 4000 proximally adjacent the distal end of wire
4000) to undergo transverse vibration (to break up the
occlusion).
[0051] In general, the spacing of nodes 4050 and anti-nodes 4060 is
selected based on the intended use of ultrasound vibration system
1000 (e.g., the condition to be treated with system 1000).
Generally, nodes 4050 can be evenly spaced or unevenly spaced, and
anti-nodes 4060 can be evenly spaced or unevenly spaced. In some
embodiments, some of nodes 4050 are evenly spaced and some of nodes
4050 are unevenly spaced. In certain embodiments, some of
anti-nodes 4060 are evenly spaced, and some of anti-nodes 4060 are
unevenly spaced. FIG. 2 shows an embodiment where nodes 4050 are
evenly spaced, and anti-nodes 4060 are evenly spaced.
[0052] Generally, the number of nodes 4050 and anti-nodes 4060
present along wire 4000 is selected based on the intended use of
system 1000 (e.g., the condition to be treated with system 1000).
As an example, FIG. 2 shows an embodiment where there are five
nodes 4050 and six anti-nodes. 4060 present along wire 4000. In
some embodiments, there can be fewer than five (e.g., one, two,
three, four) nodes 4050 or more than five (e.g., six, seven, eight,
nine, 10) nodes 4050 present along wire 4000. In certain 30
embodiments, there can be fewer than six (e.g., one, two, three,
four, five) nodes 4060 or more than six (e.g., seven, eight, nine,
10) nodes 4060 present along wire 4000.
[0053] The amplitude of anti-nodes 4060 is generally selected based
on the intended use of system 1000 (e.g., the condition to be
treated with system 1000). In some embodiments, the amplitude of
anti-nodes 4060 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 of anti-nodes 4060 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).
[0054] In general, the frequency of the vibrations in wire 4000 is
selected based on the intended use of system 1000 (e.g., the
condition to be treated with system 1000). In some embodiments, the
frequency of the vibrations in wire 4000 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 in wire 4000 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).
[0055] For a given design of hand piece assembly 3000 and
configuration of wire 4000, the type and frequency of vibrations in
wire 4000 (transverse and/or longitudinal), as well as the spacing,
number and amplitude of anti-nodes 4060, is determined by the
frequency of the output voltage of power supply 2000. In general,
the frequency of the output voltage of power supply 2000 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 of power
supply 2000 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).
[0056] Ultrasound vibration system 1000 can be used to treat a
variety of conditions. For example, FIGS. 3-6 show an embodiment in
which system 1000 is used to treat an occlusion 5000 in a blood
vessel 6000 of a subject (e.g., a human). Referring to FIG. 3, wire
4000 is disposed within blood vessel 6000 at a location that is
adjacent occlusion 5000. FIG. 4 shows that, after power supply 2000
is activated to provide electrical energy to hand piece assembly
3000, a distal end 4001 of wire 4000 undergoes longitudinal
vibration, allowing wire 4000 to penetrate into occlusion 5000. As
shown in FIGS. 5 and 6, a portion 4002 of wire 4000 that is
proximal to distal end 4001 undergoes transverse vibration to break
up occlusion 5000.
[0057] Referring to FIGS. 7A and 7B, hand piece assembly 3000
includes a hand piece body 3100 connected to power supply 2000 at a
proximal end 3105 by a multi-wire cable 2012 and threadably
connected to a nose cone 3115 at a distal end 3120. An irrigation
coupler hub 3125 is attached to nose cone 3115 and includes an
irrigation coupler port 3130 for connection to a fluid source
(e.g., for use in embodiments where a catheter surrounds wire 4000
so that a fluid can flow between wire 4000 and the catheter to
irrigate the region adjacent the biological material being treated
and/or to cool the wire during use). Wire 4000 extends
longitudinally from distal end 3120 of hand piece assembly 3000
through a central bore along coupler hub 3125. Hand piece body 3100
includes a power switch 3135 to control power supply 2000 and an
indicator light 7140 to indicate the operational status of system
1000. Power switch 3135 is a touch switch for which a first push
places switch 3135 in a first state (e.g., power supply 2000 on)
and a second push places switch 3135 in a second state (e.g., power
supply 2000 off).
[0058] FIG. 8 shows the internal components of the hand piece
assembly 3000 including an acoustic horn assembly 3500 generally
extending longitudinally from proximal end 3105 of hand piece body
3100 toward distal end 3120 of hand piece body 3100. Acoustic horn
assembly 3500 includes a distal horn 3510, a backmass 3515 and a
plurality of piezoelectric transducers (e.g., piezoceramic rings)
3520 disposed between horn 3510 and backmass 3515. Distal horn 3510
is mechanically connected (e.g., via a threaded connection) to a
proximal side of an acoustic coupler 3700, and wire 4000 is
metallurgically bonded to a distal side of acoustic coupler 3700.
With this arrangement, during use of system 1000, power supply 2000
provides electrical energy in the form of an oscillating voltage to
piezoelectric transducers 3520, and piezoelectric transducers 3520
convert the electrical energy to mechanical energy in the form of
vibrational energy that is transmitted to wire 4000 via acoustic
coupler 3700.
[0059] Acoustic horn assembly 3500 is secured to proximal end 3105
of hand piece body 3100 by a proximal mount 3530 configured to
house the backmass 3515. A tapered fitting 3535 is attached to the
proximal end 3105 and extends from the proximal mount 3530 to a
flexible collar 3540 surrounding the terminal end of cable 2012. A
spacer 3545 is disposed between piezoelectric transducers 3520 and
the backmass 3515. Acoustic horn assembly 3500 is secured to distal
end 3120 of hand piece body 3100 by a plurality of ball bearings
3550, a mounting ring 3555 including silicone o-rings 3560, 3565
along inner and outer surfaces, respectively, and a front retainer
ring 3570. Ball bearings 3550, mounting ring 3555, and front
retainer ring 3570 are all disposed between hand piece body 3100
and distal horn 3510. Dimples 3573 are positioned along distal horn
3510 and receive ball bearings 3550. Front retainer ring 3570
includes external threads engaging corresponding internal threads
of hand piece body 3100 such that rotation of retainer ring 3570
compresses acoustic horn assembly 3500 and piezoelectric
transducers 3520. Retainer ring 3570 can include spanner wrench
holes 3575 for receiving a tool to permit rotation of ring 3570 to
a predetermined torque.
[0060] As noted above, acoustic coupler 3700 is metallurgically
bonded (e.g., welded) to wire 4000 to allow vibrational energy to
be transmitted from piezoelectric transducers 3520 to wire 4000.
Generally, acoustic coupler 3700 and wire 4000 can be
metallurgically bonded at any desired location within acoustic
coupler 3700.
[0061] As an example, FIGS. 9A through 9D show an embodiment in
which an acoustic coupler 3700a is metallurgically bonded to wire
4000 at a location 3745a adjacent a proximal end 3705a of acoustic
coupler 3700a. Acoustic coupler 3700a includes external threads
3710a along a proximal end 3705a to threadably connect to
corresponding internal threads of the distal horn 3510 (FIG. 8).
Alternatively or additionally, acoustic coupler 3700a can include
internal threads 3710a along a proximal end 3705a to threadably
connect to corresponding external threads of the distal horn 3510.
Wrench flats 3715a permit rotation of acoustic coupler 3700a
against the distal horn 3510 to a predetermined torque. A flange
3720a extends around a central portion of coupler 3700a and engages
distal horn 3510 when attached thereto. A main bore 3725a extends
from an opening 3730a at a distal end 3735a of coupler 3700a to a
proximal bore 3740a. Wire 4000 extends through bores 3725a and
3740a, and, as noted above, is bonded with coupler 3700a at
location 3745a.
[0062] As another example, FIGS. 10A through 10C show an embodiment
in which an acoustic coupler 3700b is metallurgically bonded to
wire 4000 at a location 3745b adjacent a distal end 3735b of
acoustic coupler 3700b. Acoustic coupler 3700b includes external
threads 3710b to threadably connect to corresponding internal
threads of distal horn 3510 (FIG. 8). Wrench flats 3715b permit
rotation of coupler 3700b against distal horn 3510 to a
predetermined torque. A flange 3720b extends around a central
portion of coupler 3700b and engages distal horn 3510 when attached
thereto. A main bore 3725b extends from an opening 3730b at a
proximal end 3705b of coupler 3700b to a distal bore 3740b. Wire
4000 extends through bores 3725b and 3740b and, as noted above, is
bonded with coupler 3700b at location 3745b.
[0063] Typically, wire 4000 is metallurgically bonded with the
acoustic coupler as follows. Wire 4000 is disposed within the
acoustic coupler. The acoustic coupler and wire 4000 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 of wire 4000 and the
acoustic coupler are brought to a temperature sufficient to form a
metallurgical bond without substantially altering the physical
properties of wire 4000 and the acoustic coupler.
[0064] In some embodiments, locations of bonding 3745a, 3745b are
relatively close to an anti-node 4060 of the ultrasonic vibrations
of wire 4000 during use of system 1000. Without wishing to be bound
by theory, it is believed that such an arrangement of a bond
location can improve the ultrasonic transfer efficiency of system
1000 and/or decrease localized heating in system 1000 (e.g.,
localized heating in the ultrasonic coupler and/or wire 40000
during use of system 1000).
[0065] In certain embodiments, the diameter of openings 3730a,
3730b in couplers 3700a, 3700b is about the same as the
cross-sectional diameter of wire 4000. For example, in some
embodiments, the cross-sectional diameter of wire 4000 is at least
about 75% (e.g., at least about 85%, at least about 95%) of the
cross-sectional diameter of openings 3730a, 3730b. Without wishing
to be bound by theory, it is believed that using a cross-sectional
diameter for openings 3730a, 3730b that is similar to the
cross-sectional diameter of wire 4000 can improve the ultrasonic
transfer efficiency of system 1000.
[0066] 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 by power supply 2000 to hand
piece assembly 3000, and Y is the amount of mechanical energy in
wire 4000 (in the form of ultrasonic vibrations in wire 4000). In
certain embodiments, system 1000 has an ultrasonic transfer
efficiency of about 1:10 (or about ten percent) or greater. System
1000 can, for example, have an ultrasonic transfer efficiency of
about 1:10 (or about ten percent) to about 1:2 (or about 50
percent).
[0067] In some embodiments, after assembly and prior to wire 4000
being bent, the combined length of wire 4000 and the acoustic
coupler in the longitudinal direction of wire 4000 (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, for coupler 3700a, the relevant length is the length
of wire 4000 in the longitudinal direction, and, for coupler 3700b,
the relevant length is the length from proximal end 3705b to the
distal end of wire 4000. In certain embodiments, wire 4000 has a
length substantially equal to the product of one-quarter wavelength
and an odd multiplier (e.g., about 51/4 wavelengths, about 111/4
wavelengths, or about 131/4 wavelengths).
[0068] Typically, part of the path of electrical communication
between piezoelectric transducers 3520 and power supply 2000
includes one or more electrodes and one or more leads. As an
example, FIGS. 11A through 11C show acoustic horn assembly 3500
attached to coupler 3700a, electrodes 3800 in electrical
communication with piezoelectric transducers 3520, and leads 3805
in electrical communication with electrodes 3800. As another
example, FIGS. 12A though 12C show acoustic horn assembly 3500
attached to coupler 3700b, electrodes 3800 in electrical
communication with piezoelectric transducers 3520, and leads 3805
in electrical communication with electrodes 3800. As also shown in
FIGS. 12A through 12C, in some embodiments, leads 3805 connect to a
memory 3014 in hand piece assembly 3000. Memory 3014 can transmit
information to and from power supply 2000 over cable 2012 (see
discussion below).
[0069] Examples of materials from which distal horn 3510 can be
formed include metals (e.g., titanium, stainless steel, aluminum)
and alloys.
[0070] Examples of materials from which backmass 3515 can be formed
include metals (e.g., titanium, stainless steel) and alloys.
[0071] 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).
[0072] In some embodiments, acoustic coupler 3700 is made from a
metal (e.g., titanium, stainless steel, aluminum) and/or one or
more alloys.
[0073] In general, electrodes 3800 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).
[0074] Referring to FIGS. 13A and 13B, (unbent) wire 4000 has a
proximal end 4010, a distal end 4020 and a longitudinal axis 4015
that extends between ends 4010 and 4020. An acoustic coupler 3700
is adjacent proximal end 4010 of wire 4000. Wire 4000 includes a
series of transformer sections 4025, 4030, 4035, and 4040, across a
plurality of transitions 4050a, 4050b, 4050c. Transformer sections
4025, 4030, 4035 and 4040 have diameters D.sub.1, D.sub.2, D.sub.3
and D.sub.4, lengths L.sub.1, L.sub.2, L.sub.3 and L.sub.4, and
cross-sectional areas A.sub.1, A.sub.2, A.sub.3 and A.sub.4, all
respectively. The physical properties and dimensions of transformer
sections 4025, 4030, 4035 and 4040 impact the characteristics of
the ultrasonic vibrations present in transformer sections 4025,
4030, 4035 and 4040. 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
of wire 4000 may be the same as or different from the properties of
the ultrasonic vibrations in one or more other sections of wire
4000.
[0075] As an example, the ratio of the diameters of adjacent
transformer sections of wire 4000 impacts the ratio of the
amplitudes of the vibrations in these sections of wire 4000. For
example, the ratio D.sub.1:D.sub.2 impacts the ratio of the
amplitude of the vibrations in section 4025 to the amplitude of the
vibrations in section 4030. In general, as the ratio of adjacent
diameters increases (e.g., as the ratio D.sub.1:D.sub.2 increases),
the ratio of the vibrational amplitude in the adjacent sections
(e.g., the ratio of the vibrational amplitude in section 4025 to
the vibrational amplitude in section 4030) also increases, and as
the ratio of adjacent diameters decreases (e.g., as the ratio
D.sub.1:D.sub.2 decreases), the ratio of the vibrational amplitude
in the adjacent sections (e.g., the ratio of the vibrational
amplitude of section 4025 to the vibrational amplitude in section
4030) also decreases.
[0076] As another example, the ratio A:B, where A is the ratio of
the diameter to the length in one section of wire 4000 and B is the
ratio of the diameter to the length in an adjacent section of wire
4000, 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 A.sub.4025:B.sub.4030 increases), 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 from section 4025 to section
4030) also increases, and as the ratio A:B decreases (e.g., as the
ratio A.sub.4025:B.sub.4030 decreases), 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 from section 4025 to section 4030) also
decreases.
[0077] As a further example, the ratio of the flexural stiffness of
adjacent transformer sections of wire 4000 also impacts the
potential for going from a transverse vibrational mode to a
longitudinal vibrational mode when going from one section of wire
4000 to the adjacent section of wire 4000. For example, going from
a section of wire 4000 that has a relatively high flexural
stiffness to an adjacent section of wire 4000 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 of wire 4000 that has a relatively
low flexural stiffness to an adjacent section of wire 4000 that has
a relatively high flexural stiffness tends to decrease the
potential for changing from a longitudinal vibrational mode to a
transverse vibrational mode.
[0078] In general, consideration is also given to the intended use
of system 1000 (e.g., the condition to be treated with system 1000)
when selecting the dimensions of sections 4025, 4030, 4035 and
4040. As an example, the diameters of the transformer sections of
wire should not be so large as to prevent wire 4000 from being able
to fit within a desired portion (e.g., blood vessel) of a subject
to be treated. As another example, the dimensions of wire 4000 can
be selected so that wire 4000 is sufficiently flexible so that wire
4000 can be navigated through the relevant portions (e.g., the
vasculature) of a subject to be treated. As a further example, wire
4000 should be sufficiently long so that the length of the portion
of wire 4000 that is to undergo ultrasonic vibration during use of
system 1000 (e.g., the length of sections 4025, 4030, 4035 and/or
4040) can reach a desired portion (e.g., an occlusion in a blood
vessel) of a subject to be treated.
[0079] Wire 4000, as illustrated in FIGS. 13A and 13B, decreases in
diameter from its proximal end toward its distal end. As a result,
the amplitude of transverse vibrations in wire 4000 generally
increase from its proximal end to its distal end, and the amplitude
of longitudinal vibrations in wire 4000 generally decrease from its
proximal end to its distal end. In some embodiments, wire 4000 is
configured so that distal most section 4040 has the greatest
transverse vibrational amplitude along wire 4000 and is sized such
that section 4040 can reach the desired portion of the subject to
be treated.
[0080] In general, wire 4000 can be prepared as desired. In some
embodiments, wire 4000 is prepared using a process that involves
little or no plastic deformation and/or work hardening of the
material that forms wire 4000. In certain embodiments, wire 4000 is
prepared using a process that creates little or no change in the
mechanical and/or acoustic properties of the material that forms
wire 4000.
[0081] An exemplary process for preparing wire 4000 is as follows.
The transformer sections of wire 4000 are formed by grinding with a
grinding wheel while exposing wire 4000 to a lubricant. The
grinding wheel is made of a material that is sufficiently hard to
reduce the diameter of wire 4000 to form the transformer sections
of wire 4000. An example of a grinding wheel material is silicone
carbide. Examples of lubricants that can be used include oils
(e.g., water soluble oils).
[0082] In some embodiments, designing system 1000 can involve using
finite element analysis to model one or more components in system
1000. For example, FIG. 14 shows an acoustic horn assembly 3500a as
modeled using finite element analysis. Acoustic horn assembly 3500a
has a proximal end 3505a, a distal horn 3510a, a nose cone 3115a
and transducers 3520a. An acoustic coupler 3700c is attached to
acoustic horn assembly 3500a. The average distance of transducers
3520a from proximal end 3505a is 1.12 inches. Distal horn 3510a
engages hand piece body at the dimples along ball bearings (see
discussion above) at a location that is 3.28 inches from proximal
end 3505a. The distance from proximal end 3505a of acoustic horn
assembly 3500a to a distal end 3735c of acoustic coupler 3700c is
4.68 inches. Proximal end 3505a is 3.507 inches from the proximal
end of nose cone 3115a is 3.507.
[0083] FIGS. 15A through 15C are graphs of the longitudinal mode
displacement as a function of the position along acoustic horn
assembly 3500a, as modeled using finite element analysis and based
on the model shown in FIG. 14. FIG. 15A shows that a first node is
located 1.12 inches from proximal end 3505a. FIG. 15B shows that a
second node is located 3.28 inches from proximal end 3505a. FIG.
15C shows the longitudinal mode displacement along the entire
length of acoustic horn assembly 3500a. As shown in FIG. 15C,
acoustic horn assembly 3500a supports a full wavelength along its
length. Thus, FIGS. 14 and 15A through 15C 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.
[0084] 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 for system 1000 to
be designed so that a node is not present at the acoustic coupler
(whether wire 4000 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).
[0085] As discussed above, power supply 2000 is in electrical
communication with hand piece assembly 3000. FIG. 16 shows that
power supply 2000 is electrically connected to hand piece assembly
3000 by multi-wire cable 2012 so that power supply 2000 can deliver
electrical energy to hand piece assembly 3000. In addition to
providing an electrical energy path from power supply 2000 to hand
piece assembly 3000, cable 2012 provides a communication path
between power supply 2000 and hand piece assembly 3000 so that
information (e.g., operational parameters 3016 for system 1000) can
be transferred between power supply 2000 and hand piece assembly
3000. For example, in some embodiments, multi-wire cable 2012
includes a first wire for communicating information between hand
piece assembly 3000 and power supply 2000 and a second wire for
transmitting power from power supply 2000 to hand piece assembly
3000 (e.g., to piezoelectric elements 3520 of acoustic horn
assembly 3500 of hand piece assembly 3000). In addition, multi-wire
cable 2012 can include a third, ground wire.
[0086] Power supply 2000 includes a control unit 2002, a user
interface/display 2004, an input device 2006, a voltage controlled
oscillator (VCO) 2008, and a memory 2010.
[0087] Control unit 2002 monitors and adjusts the operation of
ultrasound vibration system 1000 (see discussion below).
[0088] User interface/display 2004 provides a visual display on
power supply 2000. User interface/display 2004 can display various
information, such as instructions for a user, status information
(e.g., information that indicates whether the ultrasound vibration
system 1000 is on or off, information that indicates whether power
is being supplied to hand piece assembly 3000, information that
indicates the amount of time left before system 1000 will disable
hand piece assembly 3000), operational parameters (e.g., a voltage
output of VCO 2008, a current delivered to hand piece assembly
3000, a temperature of acoustic horn assembly 3500, identification
information for hand piece assembly 3000, a resonant frequency of
acoustic horn assembly 3500, a temperature of wire 4000, a resonant
frequency of wire 4000), 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 assembly 3000, a message reporting the
source of an error in system 1000, a message requesting action or
feedback from an operator, a message displaying a current state of
system 1000), alarms (e.g., alarms indicating a warning of a
failure in the system 1000, such as an alarm indicating that a
battery is low, an alarm indicating that the temperature of hand
piece assembly 3000 is above a predetermined value, an alarm
indicating a maximum activation period of hand piece assembly 3000
has been exceeded, an alarm indicating that a maximum
post-activation use period of hand piece assembly 3000 has been
exceeded), or combinations thereof.
[0089] Input device 2006 allows a user to program or modify certain
operational parameters of ultrasound vibration system 1000. Input
device 2006 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.
[0090] VCO 2008 is in electrical communication with hand piece
assembly 3000 and provides an oscillating voltage (e.g., a
sinusoidal voltage) to hand piece assembly 3000 that causes wire
4000 to vibrate during use. In general, the frequency of the output
voltage of VCO 2008 can be changed during use of ultrasound
vibration system 1000 to respond to changes in a resonant frequency
(e.g., the fundamental resonant frequency or a harmonic of the
fundamental resonant frequency) of acoustic horn assembly 3500 of
hand piece assembly 3000. For example, an input voltage to VCO 2008
can be changed during use so that the frequency of the output
voltage of VCO 2008 remains substantially equal to the resonant
frequency of acoustic horn assembly 3500, as discussed in more
detail below.
[0091] Memory 2010 stores information (e.g., one or more
operational parameters) that is used to operate ultrasound
vibration system 1000.
[0092] Hand piece assembly 3000 includes memory 3014, a user
interface 3018, and sensors 3020.
[0093] In general, memory 3014 stores information (e.g., one or
more operational parameters 3016 for hand piece assembly 3000) that
is used to operate ultrasound vibration system 1000. Generally, the
information stored in memory 3014 can be user modifiable or
non-user modifiable. In some embodiments, some of the information
(e.g., one or more of the operational parameters 3016) stored in
memory 3014 can be user modifiable, and some of the other
information (e.g., one or more of the other operational parameters
3016) stored in memory 3014 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) of memory 3014 such that, after this
information is initially programmed for hand piece assembly 3000,
it can not be changed by an operator. As an example, in some
embodiments, one or more of the operational parameters 3016 (e.g.,
maximum activation period of hand piece assembly 3000, maximum
post-activation use period of hand piece assembly 3000, maximum
operational temperature for acoustic horn assembly 3500, maximum
operational temperature for wire 4000) can be pre-programmed into
memory 3014 prior to distributing hand piece assembly 3000 for use
(e.g., during manufacture and/or assembly of hand piece assembly
3000).
[0094] Examples of operational parameters 3016 include an output
voltage of VCO 2008, a current in hand piece assembly 3000, a
temperature of one or more components of hand piece assembly 3000,
the maximum activation period of hand piece assembly 3000, the
maximum post-activation use period of hand piece assembly 3000, a
voltage to be applied to VCO 2008, the resonant frequency of
acoustic horn assembly 3500 (e.g., as determined during the
manufacture of acoustic horn assembly 3500, or as determined during
the use of system 1000), the resonant frequency of wire 4000 (e.g.,
as determined during the manufacture of wire 4000, or as determined
during the use of system 1000), a temperature of wire 4000,
identification information (e.g., for hand piece assembly 3000,
wire 4000, and/or power supply 2000), and a medical procedure to be
performed with system 1000 (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).
[0095] User interface 3018 can display information that may be
useful for the operator during use of system 1000. Examples of such
information include one or more operational parameters 3016, one or
more messages (see discussion below), or a combination thereof.
[0096] Sensors 3020 are generally used to monitor one or more of
the operational parameters 3016 (e.g., voltage, current,
temperature, stress, strain) of hand piece assembly 3000 (e.g., of
acoustic horn assembly 3500 of hand piece assembly 3000) and/or
wire 4000 during operation of ultrasound vibration system 1000.
Sensors 3020 provide information to power supply 2000 via cable
2012, and, in response, power supply 2000 can modify the operation
of hand piece assembly 3000 (e.g., by increasing the frequency of
the output voltage of VCO 2008, by decreasing the frequency of the
output voltage of VCO 2008). Alternatively or additionally, one or
more of operational parameters 3016 can be monitored by power
supply 2000. In some embodiments, for example, the voltage and
current in hand piece assembly 3000 are monitored by power supply
2000 while the temperature of hand piece assembly 3000 (e.g., air
temperature within hand piece assembly 3000) is monitored by sensor
3020 in hand piece assembly 3000.
[0097] FIG. 17 is a flow chart of an exemplary initialization and
activation/operation process 7000 for system 1000. Operational
parameters 3016 are stored in memory 3014 of hand piece assembly
3000 (7010). Hand piece assembly 3000 is connected to power supply
2000 (7020), and one or more of the operational parameters 3016 are
transferred from memory 3014 to memory 2010 (7030). Based on the
operational parameter(s) 3016 transferred to memory 2010, power
supply 2000 configures the operational parameter(s) (e.g., the
amplitude of the output voltage of VCO 2008) for initializing
system 1000 (7040). Operational parameters 3016 can also include a
frequency range used to sweep the output frequency of VCO 2008 to
determine a resonant frequency of acoustic horn assembly 3500.
Based on operational parameters 3016, an initial frequency sweep
and tuning procedure is performed to configure the frequency of the
output voltage of VCO 2008 for initializing system 1000. After
initializing system 1000, power supply 2000 generates a voltage
signal that is transferred to hand piece assembly 3000 to activate
and/or operate hand piece assembly 3000 (7050).
[0098] Acoustic horn assembly 3500 can be designed to vibrate in a
longitudinal vibration mode. Acoustic horn assembly 3500 can
vibrationally resonate at its fundamental resonant frequency and at
harmonics of its fundamental resonant frequency. Exciting acoustic
horn assembly 3500 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 of
acoustic horn assembly 3500 where acoustic coupler 1700 is located.
The particular mode and harmonic frequency of excitation or
vibration of acoustic horn assembly 3500 is generally determined by
design and can be selected based on the intended use of system
1000. The particular mode and harmonic frequency of excitation or
vibration of acoustic horn assembly 3500 can, for example, be
selected based on the desired mode and frequency of the attached
wire 4000. In some embodiments, system 1000 is configured so that,
during use, acoustic horn assembly 3500 vibrates in a longitudinal
mode at the second harmonic of its fundamental resonant frequency.
However, acoustic horn assembly 3500 can be designed to vibrate in
other modes and/or at other harmonic frequencies, depending on the
intended use of system 1000.
[0099] In general, the resonant frequency (e.g., the fundamental
resonant frequency or a harmonic of the fundamental resonant
frequency) of acoustic horn assembly 3500 depends upon a number of
parameters, some of which may be relatively constant during use of
system 1000 and some of which may change a substantial amount
during use of system 1000. Typically, the resonant frequency of
acoustic horn assembly 3500 depends on one or more physical
properties (e.g., length, cross sectional shape, cross sectional
area) of acoustic horn assembly 3500 and/or one or more material
properties (e.g., yield strength, material modulus) of acoustic
horn assembly 3500. Generally, the resonant frequency of acoustic
horn assembly 3500 also depends on the temperature of acoustic horn
assembly 3500. As an example, as the temperature of acoustic horn
assembly 3500 increases, the resonant frequency of acoustic horn
assembly 3500 can decrease. As another example as the temperature
of acoustic horn assembly 3500 decreases, the resonant frequency of
acoustic horn assembly 3500 can increase. Thus, it is generally
desirable for power supply 2000 to be capable of modifying the
frequency of the output voltage of VCO 2008 to hand piece assembly
3000 so that, as the resonant frequency of acoustic horn assembly
3500 changes, the frequency of the output voltage of VCO 2008 also
changes to be at about the same frequency as (e.g., identical to)
the resonant frequency of acoustic horn assembly 3500.
[0100] In some embodiments, the resonant frequency of acoustic horn
assembly 3500 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).
[0101] Wire 4000 can be designed to vibrate in a longitudinal
vibration mode. Wire 4000 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 of wire 4000
generally depends upon a number of parameters, some of which may be
relatively constant during use of system 1000 and some of which may
change a substantial amount during use of system 1000. Typically,
the resonant frequency of wire 4000 depends on one or more physical
properties (e.g., length, cross sectional shape, cross sectional
area) of wire 4000 and/or one or more material properties (e.g.,
yield strength, material modulus) of wire 4000. Generally, the
resonant frequency of wire 4000 also depends on the temperature of
wire 4000 and/or the mechanical loading of wire 4000 (e.g., the
degree to which wire 4000 is bent). As an example, as the
temperature of wire 4000 increases, the resonant frequency of wire
4000 can make a corresponding change. As another example as the
temperature of wire 4000 decreases, the resonant frequency of wire
4000 can make a corresponding change.
[0102] In certain embodiments, the longitudinal resonant frequency
(e.g., the fundamental longitudinal resonant frequency or a
harmonic of the fundamental longitudinal resonant frequency) of
acoustic horn assembly 3500 differs from the longitudinal resonant
frequency (e.g., the fundamental longitudinal resonant frequency or
a harmonic of the fundamental longitudinal resonant frequency) of
wire 4000. The longitudinal resonant frequency of acoustic horn
assembly 3500 can, for example, differ from the nearest
longitudinal resonant frequency of wire 4000 by about one kHz to
about six kHz (e.g., about three kHz). Wire 4000 and acoustic horn
assembly 3500 can, for example, be designed such that their
respective longitudinal resonant frequencies differ from one
another throughout use of system 1000. Maintaining a difference
between the longitudinal resonant frequencies of wire 4000 and
acoustic horn assembly 3500 can help power supply 2000 to lock onto
the longitudinal resonant frequency of acoustic horn assembly 3500
during use. The difference between the longitudinal resonant
frequencies of wire 4000 and acoustic horn assembly 3500 can, for
example, help to provide a measurable phase difference between the
voltage and current delivered to acoustic horn assembly 3500 by
power supply 2000 to help power supply 2000 lock onto the
longitudinal resonant frequency of acoustic horn assembly 3500
during use.
[0103] In certain embodiments, ultrasound horn assembly 3500 has a
longitudinal fundamental resonant frequency of about 20 kHz and
wire 4000 has a fundamental resonant frequency of about 2 kHz. In
such embodiments, during use, ultrasound horn assembly 3500 can be
excited at 40 kHz, which is the second harmonic of its fundamental
longitudinal resonant frequency. The vibration of acoustic horn
assembly 3500 can cause wire 4000 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 of wire 4000. This frequency can alternatively fall
between the 19.sup.th and 20.sup.th or 24.sup.th and 25.sup.th,
harmonics of the fundamental longitudinal resonant frequency of
wire 4000. Because wire 4000 is excited at a frequency between
harmonics of its longitudinal resonant frequency, wire 4000 does
not vibrate at its resonant frequency.
[0104] FIG. 18 is a flow chart of an exemplary process 8000 for
modifying the vibrational frequency of acoustic horn assembly 3500
as the resonant frequency of acoustic horn assembly 3500 changes.
Power supply 2000 initially determines the resonant frequency of
acoustic horn assembly 3500, and power supply 2000 sets VCO 2008 to
generate an output voltage at a frequency such that acoustic horn
assembly 3500 vibrates at a frequency that is about the same as
(e.g., identical to) the resonant frequency of acoustic horn
assembly 3500 (8010). As ultrasound vibration system 1000 is being
used, power supply 2000 determines if the resonant frequency of
acoustic horn assembly 3500 has changed (8020). If the resonant
frequency of acoustic horn assembly 3500 has not changed, power
supply 2000 continues to supply the same input voltage to VCO 2008,
causing VCO 2008 to provide the same output voltage (e.g., a
voltage having the same frequency) to acoustic horn assembly 3500
(8030). If the resonant frequency of acoustic horn assembly 3500
has changed, power supply 2000 adjusts the input voltage to VCO
2008, changing the frequency of the output voltage of VCO 2008 such
that acoustic horn assembly 3500 vibrates at a frequency that is
about the same as (e.g., identical to) the new resonant frequency
of acoustic horn assembly 3500 (8040). As an example, in some
embodiments in which the resonant frequency of acoustic horn
assembly 3500 decreases during use of system 1000, power supply
2000 can decrease the frequency of the output voltage of VCO 2008.
As another example, in certain embodiments in which the resonant
frequency of acoustic horn assembly 3500 increases during use of
system 1000, power supply 2000 can increase the frequency of the
output voltage of VCO 2008.
[0105] In general, power supply 2000 can determine the resonant
frequency of acoustic horn assembly 3500 using any desired method
or combination of methods. In some embodiments, power supply 2000
determines the resonant frequency of acoustic horn assembly 3500
based on the phase difference between the voltage in acoustic horn
assembly 3500 and the current in acoustic horn assembly 3500.
Typically, power supply 2000 determines the voltage in acoustic
horn assembly 3500 and the current in acoustic horn assembly 3500
via one or more current and voltage sensing devices.
[0106] FIG. 19 shows a graph of a voltage signal 9000a and a
current signal 9010a where a phase difference 9050 between these
signals is non-zero, and FIG. 20 shows a graph of a voltage signal
9000 and a current signal 9010 where the phase difference between
these signals is zero. In FIG. 19, voltage signal 9000a has a
period 9020a, a maximum value 9030a, and a minimum value 9040a, and
current signal 9010b has a period 9020b, a maximum value 9030b, and
a minimum value 9040b. In FIG. 20, both voltage signal 9000 and
current signal 9010 have a period 9020, a maximum value 9030 and a
minimum value 9040.
[0107] During use of system 1000, power supply 2000 monitors both
the voltage in acoustic horn assembly 3500 and the current in
acoustic horn assembly 3500 to determine the size of the phase
difference between these signals. If the phase difference is zero,
power supply 2000 does not change the frequency of the output
voltage of VCO 2008. However, if the phase difference is non-zero,
power supply 2000 changes the frequency of the output voltage of
VCO 2008 so that acoustic horn assembly 3500 vibrates at a
frequency that is about the same as (e.g., identical to) the
resonant frequency of acoustic horn assembly 3500.
[0108] FIG. 21 shows a block diagram of an exemplary control unit
10001 designed to monitor the voltage in acoustic horn assembly
3500 and the current in acoustic horn assembly 3500, and to modify
the frequency of the output voltage of VCO 2008 so that, during use
of system 1000, the vibrational frequency of acoustic horn assembly
3500 can be adjusted to be about the same as (e.g., identical to)
the resonant frequency of acoustic horn assembly 3500.
[0109] Control unit 10001 includes an analog control loop 10000 and
a digital control loop 10010. Analog control loop 10000 produces a
voltage 10060 that is based on the phase difference between the
voltage in acoustic horn assembly 3500 and the current in acoustic
horn assembly 3500. Voltage 10060 acts as an input voltage to VCO
2008. Similarly, digital control loop 10010 produces a voltage
10070 that is based on the phase difference between the voltage in
acoustic horn assembly 3500 and the current in acoustic horn
assembly 3500, and voltage 10070 acts as an input to voltage VCO
2008. By providing respective input voltages to VCO 2008, analog
control loop 10000 and digital control loop 10010 determine the
frequency of the output voltage of VCO 2008.
[0110] Voltage 10060 has a maximum range that is predetermined
(e.g., set in memory) based on the expected range for the resonant
frequency of acoustic horn assembly 3500 during use of system 1000,
and voltage 10070 has a maximum range that is predetermined (e.g.,
set in memory) based on the expected range for the resonant
frequency of acoustic horn assembly 3500 during use of system 1000.
As a result, the maximum amount by which analog control loop 10000
can adjust the frequency of the output voltage of VCO 2008 is
predetermined, and the maximum amount by which digital control loop
10010 can adjust the frequency of the output voltage of VCO 2008 is
predetermined. In general, the maximum range of voltage 10070 is
greater than the maximum range of voltage 10060. With this
arrangement, digital control loop 10010 sets a center frequency for
the output voltage of VCO 2008, and analog loop 10000 then
dynamically implements deviations in the frequency of the output
voltage of VCO 2008 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
in hand piece assembly 3000 and the voltage in hand piece assembly
3000.
[0111] Analog control loop 10000 establishes the value of voltage
10060 as follows. A voltage current phase detector 10040 is placed
in electrical communication with hand piece assembly 3000, and
phase detector 10040 determines the phase difference between the
voltage applied to acoustic horn assembly 3500 and the resulting
current in acoustic horn assembly 3500. Phase detector 10040
provides to error integrator 10050 a signal that corresponds to the
phase difference between the voltage in acoustic horn assembly 3500
and the current in acoustic horn assembly 3500. Error integrator
10050 produces voltage 10060 based on the signal received from
phase detector 10040. Generally, the magnitude of voltage 10060 is
proportional to the magnitude of the phase difference between the
current in acoustic horn assembly 3500 and the voltage in acoustic
horn assembly 3500. In other words, if the phase difference is
relatively small amount, the magnitude of voltage 10060 is usually
relatively small, and, if the phase difference is relatively large,
the magnitude of voltage 10060 is usually relatively large. In
general, integrator 10050 is biased such that error integrator
10050 changes voltage 10060 only when the phase difference between
the voltage in acoustic horn assembly 3500 and the current in
acoustic horn assembly 3500 is outside a predetermined range. For
example, phase error integrator 10050 can be configured to change
voltage 10060 only when the absolute value of the phase difference
between the voltage in hand piece assembly 3000 and the current in
hand piece assembly 3000 is greater than about 5.degree. (e.g.,
greater than about 10.degree., greater than about 15.degree.,
greater than about 20.degree.). Typically, if the resonant
frequency of acoustic horn assembly 3500 decreases, error
integrator 10050 changes the value of voltage 10060 to decrease the
frequency of the output voltage of VCO 2008, and, if the resonant
frequency of acoustic horn assembly 3500 increases, error
integrator 10050 changes voltage 10060 to increase the frequency of
the output voltage of VCO 2008. In general, error integrator 10050
can use any appropriate method to produce voltage 10060 based on
the signal received from phase detector 10040. As an example, in
some embodiments, error integrator 10050 can include a look-up
table that informs error integrator 10050 of the appropriate value
for voltage 10060 based on the signal error integrator 10050
receives from phase detector 10040.
[0112] Digital control loop 10010 establishes the value of voltage
10070 as follows. During initialization of system 1000, the signal
produced by phase detector 10040 is the input signal for
microcontroller 10020, and during operation of system 1000 the
signal produced by error integrator 10050 is the input signal for
microcontroller 10020. Based on the input signal it receives,
microcontroller 10020 sends a digital signal to analog to DAC
10030. DAC 10030 converts the digital signal it receives from
microcontroller 10020 to an analog signal, which is voltage 10070.
Thus, microcontroller 10020 uses the signal it receives from phase
detector 10040, which corresponds to the phase difference between
the voltage in acoustic horn assembly 3500 and the current in
acoustic horn assembly 3500, to determine the signal it should send
to DAC 10030 so that voltage 10070 is changed in a manner that
achieves the desired corresponding change in the frequency of the
output voltage of VCO 2008. Microcontroller 10020 can do this, for
example, based on the maximum range of the change in the frequency
of the output voltage of VCO 2008 that voltage 10070 can make.
Typically, microcontroller 10020 sends a signal to DAC 10030 so
that DAC 10030 changes voltage 10070 in the appropriate direction
(e.g., decreasing voltage 10070 if the phase difference between the
voltage in acoustic horn assembly 3500 and the current in acoustic
horn assembly 3500 is negative, increasing voltage 10070 if the
phase difference between the voltage in acoustic horn assembly 3500
and the current in acoustic horn assembly 3500 is positive) and by
an absolute value that is proportional to the magnitude of the
phase difference between the voltage in acoustic horn assembly 3500
and the current in acoustic horn assembly 3500.
[0113] FIG. 22 shows a process 11000 for determining the initial
center frequency for the output voltage of VCO 2008. Power supply
2000 disables analog control loop 10000 (11010). This causes
voltage 10060 to be zero volts, and so the frequency of the output
voltage of VCO 2008 is determined by output voltage 10070 of
digital control loop 10010. While analog control loop 10010 is
disabled, the output signal from phase detector 10040 is the input
signal for microcontroller 10020. The amplitude of voltage 10070 is
swept through its maximum range (11020), causing the frequency of
voltage 10080 to be swept through its maximum frequency range. As
the amplitude of voltage 10070 is swept through its maximum range,
phase detector 10040 monitors the phase difference between the
voltage in acoustic horn assembly 3500 and the current in acoustic
horn assembly 3500, and provides this information to
microcontroller 10020. Microcontroller 10020 then determines the
frequency for the output voltage of VCO 2008 that results in the
smallest phase difference and will cause acoustic horn assembly
3500 to vibrate at a frequency that is about the same as (e.g.,
identical to) the resonant frequency of acoustic horn assembly 3500
(11030). Microcontroller 10020 then provides the appropriate
digital signal to DAC 10030, and DAC 10030 converts this signal to
an analog signal (voltage 10070) so that the frequency of the
output voltage of VCO 2008 results in acoustic horn assembly 3500
vibrating at a frequency that is about the same as (e.g., identical
to) the resonant frequency of acoustic horn assembly 3500 (11040).
Power supply 2000 subsequently enables analog control loop 10000
(11050), and digital control loop 10010 and analog control loop
10000 are used to dynamically adjust the output frequency of VCO
2008 via the amplitude of voltages 10060 and 10070 applied to VCO
2008, as discussed above.
[0114] During operation of system 1000, the output of error
integrator 10050 (i.e., voltage 10060) is the input to digital
control loop 10010. As a result, the output of analog control loop
10000 (i.e., voltage 10060) determines the output of digital
control loop 10010 (i.e., voltage 10070). Thus, digital control
loop 10010 dynamically changes the center frequency of the output
voltage of VCO. 2008 based on voltage 10600, which, in turn, is
based on the phase difference between the voltage in acoustic horn
assembly 3500 and the current in acoustic horn assembly 3500.
[0115] As noted above, there is a predetermined maximum range of
values for voltage 10060. This maximum range of values for voltage
10060 can be divided into multiple regions so that the amount by
which voltage 10060 causes digital control loop 10010 to change the
frequency of the output voltage of VCO 2008 depends on the region
in which voltage 10060 is located. For example, FIG. 23 shows a
maximum range 12000 of values for voltage 10060. Range 12000 is
divided into regions 12010, 12020, 12030, 12040 12050. When voltage
10060 is in region 12030, voltage 10060 causes relatively little or
no change in the frequency of the output voltage of VCO 2008. When
voltage 10060 is in region 12010, voltage 10060 causes its maximum
positive change in the frequency of the output voltage of VCO 2008,
and, when voltage 10060 is in region 12050, voltage 10060 causes
its maximum negative change in the frequency of the output voltage
of VCO 2008. When voltage 10060 is in region 12020, voltage 10600
causes a positive change in the frequency of the output voltage of
VCO 2008 that is greater than that caused when voltage 10060 is in
region 12030 but less than when voltage 10060 is in region 12010.
When voltage 10060 is in region 12040, voltage 10060 causes a
negative change in the frequency of the output voltage of VCO 2008
that is greater than that caused when voltage 10060 is in region
12030 but less than when voltage 10060 is in region 12050.
[0116] In general, the magnitude of regions 12010,12020, 12030,
12040, 12050 can be selected as desired. For example, in some
embodiments, these regions can have the following magnitudes.
Region 12030 can be centered at the middle of range 12000, and
region 12030 can occupy at most about 70% (e.g., at most about 60%,
at most about 50%, at most about 40%) of range 12000. Region 12020
can have a minimum value corresponding to the maximum value of
region 12030, and can occupy at most about 30% (e.g., at most about
25%, at most about 20%, at most about 15%) of range 12000. Region
12040 can have a maximum value corresponding to the minimum value
of region 12030, and can occupy at most about 30% (e.g., at most
about 25%, at most about 20%, at most about 15%) of range 12000.
Region 12010 can have a minimum value corresponding to the maximum
value of region 12020 and a maximum value corresponding to the
maximum value of voltage 10060. Region 12010 can occupy at most
about 10% (e.g., at most about 7%, at most about 5%, at most about
3%) of range 12000. Region 12050 can have a maximum value
corresponding to the minimum value of region 12040 and a minimum
value corresponding to the minimum value of voltage 10060. Region
12050 can occupy at most about 10% (e.g., at most about 7%, at most
about 5%, at most about 3%) of range 12000.
[0117] FIG. 24 shows a flow chart of an exemplary process 13000 for
modifying the center frequency of the output voltage of VCO 2008
based on the magnitude of voltage 10060, using regions 12010,
12020, 12030, 12040 and 12050 of maximum range 12000 for voltage
10060. First, voltage 10060 is input to microcontroller 10020
(13010). Microcontroller 10020 determines the region in which
voltage 10060 is located (13020). If voltage 10060 is in region
12030, microcontroller 10020 sends a signal to DAC 10030 so that
voltage 10070 does not change, resulting in no change in the center
frequency of the output voltage of VCO 2008 (13030). If voltage
10060 is in region 12020 or region 12040, microcontroller 10020
sends a signal to DAC 10030 so that voltage 10070 changes but by a
relatively small amount (13040). This causes the center frequency
of the output voltage of VCO 2008 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 of VCO 2008. For example, voltage 10070 can be adjusted in
relatively small frequency increments such that the change in the
center frequency of the output voltage of VCO 2008 is relatively
slow. If voltage 10060 is in region 12010 or region 12050,
microcontroller 10020 sends a signal to DAC 10030 so that voltage
10070 changes by a relatively large amount (13050). This causes the
center frequency of the output voltage of VCO 2008 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 of VCO 2008. For example, voltage 10070 can be
adjusted in relatively large frequency increments such that the
change in center frequency of the output voltage VCO 2008 is
relatively fast.
[0118] In general, for a given region of voltage 10060, the amount
by which voltage 10070 changes is based on the desired change in
the frequency of the output voltage of VCO 2008 for the region of
voltage 10060, bearing in mind that, because voltage 10070 has a
maximum range of values, there is also a corresponding maximum
range of change in the frequency of the output voltage of VCO 2008
that can be caused by voltage 10070. As an example, if voltage
10060 is in region 12010 or 12050, then microcontroller 10020 can
send a signal to DAC 10030 so that voltage 10070 results in a
change in the frequency of the output voltage of VCO 2008 that is
from about 25% to about 50% of the maximum range of change in the
frequency of the output voltage of VCO 2008 that can be caused by
voltage 10070. As another example, if voltage 10060 is in region
12020 or 12040, then microcontroller 10020 can send a signal to DAC
10030 so that voltage 10070 results in a change in the frequency of
the output voltage of VCO 2008 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 of VCO 2008 that can be caused by voltage 10070.
[0119] In some embodiments, if certain conditions are satisfied, it
may be desirable to be able to prevent hand piece assembly 3000
from being initially enabled and/or to disable hand piece assembly
3000 after it has been initially enabled. As an example, in
embodiments in which hand piece assembly 3000 has a maximum time
period for which it can be activated (maximum activation period),
hand piece assembly 3000 can be disabled if it has met or exceeded
this time period. As another example, in embodiments in which hand
piece assembly 3000 has a maximum period time after activation that
it can be used (maximum post-activation use period), hand piece
assembly 3000 can be disabled if it has met or exceeded this time
period. As a further example, in embodiments in which acoustic horn
assembly 3500 has a temperature that it should not exceed during
use of system 1000, hand piece assembly 3000 can be disabled if
acoustic horn assembly 3500 is at or above this temperature. As
another example, in embodiments in which wire 4000 has a
temperature that it should not exceed during use of system 1000,
hand piece assembly 3000 can be disabled if wire 4000 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 of acoustic horn assembly 3500
and the resonant frequency of acoustic horn assembly 3500, hand
piece assembly 3000 can be disabled if this maximum frequency
difference is met or exceeded. In some embodiments, if it is
determined that hand piece assembly 3000 should be disabled, hand
piece assembly 3000 is permanently disabled. In certain
embodiments, if it is determined that hand piece assembly 3000
should be disabled, hand piece assembly 3000 is temporarily
disabled.
[0120] FIG. 25 shows an exemplary process 15000 for enabling hand
piece assembly 3000 and subsequently disabling hand piece assembly
3000 where hand piece assembly 3000 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 in memory 3014 in hand piece assembly
3000 (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 of hand piece
assembly 3000 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 of hand piece assembly 3000 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
assembly 3000 is connected to power supply 2000 (15020), and system
1000 determines if hand piece assembly 3000 has been used
previously (15030). If hand piece assembly 3000 has not been used
before (i.e., hand piece assembly 3000 is being activated for the
first time), system 1000 stores in memory 3014 a value indicating
the time the hand piece assembly is first activated (15040). System
1000 then compares the amount of time that hand piece assembly 3000
has been activated to the maximum activation period of hand piece
assembly 3000 (15050). If the amount of time that hand piece
assembly 3000 has been activated is equal to or greater than the
maximum activation period of hand piece assembly 3000, system 1000
prevents hand piece assembly 3000 from being enabled (15060). If
the amount of time that hand piece assembly 3000 has been activated
is less than the maximum activation period of hand piece assembly
3000, system 1000 compares the period of time since hand piece
assembly 3000 was activated to the maximum post-use activation
period of hand piece assembly 3000 (15070). If the period of time
since hand piece assembly 3000 was activated is equal to or greater
than the maximum post-activation use period of hand piece assembly
3000, system 1000 prevents hand piece assembly 3000 (2210) from
being enabled (15060). If the period of time since hand piece
assembly 3000 was first activated is less than the maximum
post-activation use period of hand piece assembly 3000, system 1000
enables operation of hand piece assembly 3000 (15080). System 1000
goes through this loop at predetermined time intervals so that,
after hand piece assembly 3000 is enabled, hand piece assembly 3000
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).
[0121] In some embodiments, system 1000 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 assembly
3000), to a user a given parameter is approaching a critical value.
As an example, system 1000 can provide an indication to a user as
acoustic horn assembly 3500 is approaching its maximum use
temperature. As an additional example, system 1000 can provide an
indication to a user as wire 4000 is approaching its maximum use
temperature. As another example, system 1000 can provide an
indication to a user as hand piece assembly 3000 is approaching its
maximum activation period. As a further example, system 1000 can
provide an indication to a user as hand piece assembly 3000 is
approaching its maximum post-activation use period. As an
additional example, system 1000 can provide an indication to a user
as the difference between the vibrational frequency of acoustic
horn assembly 3500 and the resonant frequency of acoustic horn
assembly 3500 is approaching its maximum value.
[0122] While certain embodiments have been described, other
embodiments are possible.
[0123] As an example, while embodiments have been described in
which power switch 3135 is a touch switch, more generally, power
switch 3135 can be any switch that can move between a first state
(e.g., power supply 2000 on) and a second state (e.g., power supply
2000 off). In some embodiments, power switch 3135 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.
[0124] As another example, in some embodiments system 1000 can
include additional features. In some embodiments, system 1000 can
include a catheter that surrounds wire 4000. The catheter can, for
example, allow a fluid (e.g., an irrigation fluid, a fluid
containing a therapeutic agent, a cooling fluid) to flow between
wire 4000 and the catheter, and/or the catheter can assist in
steering wire 4000. In embodiments in which system 1000 includes a
catheter, system 1000 may include additional equipment to monitor
fluid flow through the catheter. For example, system 1000 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, system 1000
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 which wire 4000 is cooled
during use. In certain embodiments, one or more portions of system
1000 that will be disposed within a subject during use (e.g., one
or more regions of wire 4000) can include a radiopaque material. In
certain embodiments, a radiopaque material be disposed at or near
the distal end of wire 4000 so that the location of the distal end
of wire 4000 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) wire 4000. In
certain embodiments, the radiopaque material can be incorporated
into (e.g., alloyed with) the material that forms wire 4000.
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 of wire 4000 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.
[0125] 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.
[0126] 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.
[0127] As an additional example, while embodiments have been
described in which wire 4000 is metallurgically bonded with an
acoustic coupler, in certain embodiments wire 4000 and the acoustic
coupler can be coupled using other techniques. For example, wire
4000 and the acoustic coupler can be coupled with a mechanical
connection. In some embodiments, the acoustic coupler is crimped
onto wire 4000. 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.
[0128] As another example, while embodiments have been described in
which the cross-sectional shape of wire 4000 is circular, other
cross-sectional shapes may also be used. For example, the
cross-sectional shape of wire 4000 can be triangular, elliptical,
or rectangular. In some embodiments, different portions of wire
4000 have different cross-sectional shapes.
[0129] As a further example, while embodiments have been disclosed
where wire 4000 is formed of Ti-6Al-4V titanium, in certain
embodiments, wire 4000 can be formed of a different material. In
general, wire 4000 can be formed of any material capable of
supporting ultrasonic vibrations. In some embodiments, wire 4000 is
formed of a material having a flexural stiffness of at least about
1.times.10.sup.7 N/m (e.g., at least about 2.5.times.10.sup.7 N/m,
at least about 4.times.10.sup.7 N/m) and/or at most about
10.times.10.sup.7 N/m (e.g., at least about 8.5.times.10.sup.7 N/m,
at least about 7.times.10.sup.7 N/m). Examples of materials from
which wire 4000 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).
[0130] As an additional example, while embodiments of an unbent
wire 4000 have been shown, it is to be understood that, in general,
during the use of system 1000, wire 4000 will be bent. In some
embodiments, during use of system 1000, wire 4000 may have one or
more bends. In certain embodiments, when bent, wire 4000 may take
on a shape that is helical (along axis 4015). In some embodiments,
wire 4000 may bend in multiple planes (e.g., as compared to axis
4015).
[0131] As another example, while power supply 2000 has been
described as including input device 2006 to allow the user to
program or modify certain operational parameters of system 1000, 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.
[0132] As yet a further example, while embodiments have been
described in which a multi-wire cable provides communication
between power supply 2000 and hand piece assembly 3000, other
communication devices can be used. In some embodiments, a one-wire
cable can provide the communication path between power supply 2000
and hand piece assembly 3000. 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 between power supply 2000 and hand piece assembly 3000.
In some embodiments, a wireless communication system can provide
the communication path between power supply 2000 and hand piece
assembly 3000 while a wire provides the electrical current path to
deliver power from power supply 2000 and hand piece assembly 3000.
Combinations of devices are also possible.
[0133] As another example, in certain embodiments, hand piece
assembly 3000 can be labeled to indicate the procedure for which
hand piece assembly 3000 is designed to be used. Exemplary labels
include stickers applied to the hand piece assembly 3000 and/or a
package which includes the hand piece assembly 3000, a label
printed on a package which includes the hand piece assembly 3000, a
label printed on the hand piece assembly 3000, an RFID tag included
in the hand piece assembly 3000, and an RFID tag included in the
package which includes the hand piece assembly 3000. The labels can
include various information such as the procedure the hand piece
assembly 3000 is designed to be used for, the length of wire 4000,
and/or an expiration date for the hand piece assembly 3000. 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.
[0134] As a further example, while embodiments have been described
in which hand piece assembly 3000 automatically transfers
operational parameters 3016 to power supply 2000 when hand piece
assembly 3000 is connected to power supply 2000, other methods for
transferring operational parameters 3016 from hand piece assembly
3000 to power supply 2000 are possible. For example, in some
embodiments, power supply 2000 detects a connection to hand piece
assembly 3000 and power supply 2000 sends a request to hand piece
assembly 3000 for operational parameters 3016. Hand piece assembly
3000 receives the request and, in response, sends the requested
operational parameters 3016 to power supply 2000.
[0135] As an additional example, while embodiments have been
described in which memory 3014 stores one or more operational
parameters 3016, in some embodiments memory 3014 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 assembly 3000 can transfer the identifier(s) to power
supply 2000 upon connection of hand piece assembly 3000 to power
supply 2000. Power supply 2000 can use the identifier(s), for
example, to determine a set of operational parameters for
activation and/or operation of system 1000. For example, power
supply 2000 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 from memory 3014. Storing one
or more identifiers in memory 3014 can provide the advantage of
reducing the size of the memory in hand piece assembly 3000
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 of wire 4000, and the identifier(s) can
provide appropriate operational parameters for power supply 2000 to
operate system 1000 given the length of wire 4000. As another
example, in certain embodiments, the identifier(s) can indicate a
procedure to be performed with system 1000, and the identifier(s)
can provide appropriate operational parameters for power supply
2000 to operate system 1000 given the procedure to be
performed.
[0136] As another example, while embodiments have been described in
which voltage 10060 is divided into five regions, in certain
embodiments output voltage 10060 analog control loop 10000 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).
[0137] As an additional example, while embodiments have been
described in which voltage 10070 is divided into six bins, in
certain embodiments voltage 10070 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).
[0138] As a further example, in some embodiments, hand piece
assembly 3000 can include an activation switch that an operator of
system 1000 can depress to activate hand piece assembly 3000.
Examples of activation switches include buttons, touch screens and
mechanical switches. In certain embodiments, when the user
depresses the activation switch, hand piece assembly 3000 can send
a message to power supply 2000 to activate hand piece assembly
3000. Optionally, system 1000 can be designed to include
appropriate circuitry to confirm that the user has actually
depressed the activation switch before activating hand piece
assembly 3000 (e.g., to confirm that the signal received by power
supply 2000 was not an error). FIG. 26 shows a process 17000 for
confirming that an activation switch has been pressed prior to
activating hand piece assembly 3000. In order to activate hand
piece assembly 3000, an operator presses the activation switch
(17010). In response, a voltage level on hand piece assembly 3000
is changed (17020). For example, a voltage level in hand piece
assembly 3000 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 assembly 3000 also sends a serial communication to power
supply 2000 over communication line 2012 in response to activation
switch being pressed (17030). Power supply 2000 determines if both
the serial communication has been received and the voltage level in
hand piece assembly 3000 has dropped (17040). If both the serial
communication has been received and the voltage level in hand piece
assembly 3000 has dropped, hand piece assembly 3000 is enabled
(17050). Otherwise, hand piece assembly 3000 remains disabled
(17040).
[0139] While certain embodiments discussed above describe acoustic
horn assembly 3500 and wire 4000 as being designed to vibrate
longitudinally, other designs are possible. For example, acoustic
horn assembly 3500 and/or wire 4000 can be designed to vibrate
longitudinally, transversely, and/or torsionally.
[0140] Other embodiments are in the claims.
* * * * *