U.S. patent application number 14/630317 was filed with the patent office on 2015-06-18 for intracooled percutaneous microwave ablation probe.
The applicant listed for this patent is COVIDIEN LP. Invention is credited to KENLYN S. BONN, STEVEN E. BUTCHER.
Application Number | 20150164587 14/630317 |
Document ID | / |
Family ID | 40584703 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150164587 |
Kind Code |
A1 |
BONN; KENLYN S. ; et
al. |
June 18, 2015 |
INTRACOOLED PERCUTANEOUS MICROWAVE ABLATION PROBE
Abstract
A device for the treatment of tissue with microwave energy
includes an antenna assembly including outer and inner conductors,
a sealing barrier, and a cooling system. The outer and inner
conductors have a dielectric material interposed therebetween. The
cooling system minimizes the likelihood that the antenna assembly
will overheat.
Inventors: |
BONN; KENLYN S.; (LAKEWOOD,
CO) ; BUTCHER; STEVEN E.; (BERTHOUD, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COVIDIEN LP |
Mansfield |
MA |
US |
|
|
Family ID: |
40584703 |
Appl. No.: |
14/630317 |
Filed: |
February 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12395034 |
Feb 27, 2009 |
8965536 |
|
|
14630317 |
|
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|
|
61033196 |
Mar 3, 2008 |
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Current U.S.
Class: |
606/33 |
Current CPC
Class: |
A61B 18/18 20130101;
A61B 2018/00577 20130101; A61B 2017/00084 20130101; A61B 18/1815
20130101; A61B 2018/00023 20130101 |
International
Class: |
A61B 18/18 20060101
A61B018/18 |
Claims
1-20. (canceled)
21. An antenna assembly, comprising: an elongate member; an outer
conductor positioned within the elongate member; a dielectric
material disposed within the outer conductor and defining: a lumen;
a first longitudinal channel including an inlet conduit extending
therethrough; and a second longitudinal channel including an outlet
conduit extending therethrough; an inner conductor at least
partially disposed within the lumen of the dielectric material; and
a distal radiating portion extending distally from the elongate
member and defining a cooling chamber therein, wherein the inlet
and outlet conduits are configured to circulate a fluid within the
cooling chamber, the dielectric material configured to separate the
first and second longitudinal channels from the lumen to insulate
the inlet and outlet conduits from the inner conductor.
22. The antenna assembly according to claim 21, wherein the lumen
is centrally disposed within the dielectric material, and the first
and second longitudinal channels are disposed about the lumen.
23. The antenna assembly according to claim 21, further comprising
a connecting hub that defines: a first conduit coupled to the inlet
conduit; a second conduit coupled to the outlet conduit; and a
third conduit having a proximal end of the elongate member disposed
therein.
24. The antenna assembly according to claim 23, wherein the inlet
and outlet conduits extend through the first and second
longitudinal channels of the dielectric material and are coupled to
the first and second conduits of the connecting hub.
25. The antenna assembly according to claim 24, wherein the
proximal end of the elongate member includes: a first aperture
extending transversely from an outer surface of the elongate member
to the first longitudinal channel of the dielectric material; and a
second aperture extending transversely from the outer surface of
the elongate member to the second longitudinal channel of the
dielectric material.
26. The antenna assembly according to claim 25, wherein the inlet
conduit includes an inlet curved portion extending from the first
longitudinal channel of the dielectric material, through the first
aperture, and into the first conduit of the connecting hub, and the
outlet conduit includes an outlet curved portion extending from the
second longitudinal channel of the dielectric material, through the
second aperture, and into the second conduit of the connecting
hub.
27. The antenna assembly according to claim 21, further comprising
a penetrating member supported at a distal end of the elongate
member.
28. A microwave treatment system, comprising: a power supply; a
feedline coupled to the power supply, the feedline including: an
elongate member; an outer conductor positioned within the elongate
member; a dielectric material disposed within the outer conductor
and defining: a lumen; a first longitudinal channel; and a second
longitudinal channel; an inner conductor at least partially
disposed within the lumen of the dielectric material; a distal
radiating portion extending distally from the elongate member and
defining a cooling chamber therein, the cooling chamber in
communication with the first and second longitudinal channels; and
a cooling system including: a pump configured to circulate fluid;
an inlet conduit coupled to the pump and extending through the
first longitudinal channel; and an outlet conduit coupled to the
pump and extending through the second longitudinal channel, the
inlet and outlet conduits configured to circulate the fluid from
the pump to the cooling chamber, wherein the dielectric material is
configured to separate the first and second longitudinal channels
from the lumen to insulate the inlet and outlet conduits from the
inner conductor.
29. The microwave treatment system according to claim 28, wherein
the lumen is centrally disposed within the dielectric material and
the first and second longitudinal channels are disposed about the
lumen.
30. The microwave treatment system according to claim 28, further
comprising a connecting hub that defines: a first conduit coupled
to the inlet conduit of the cooling system; a second conduit
coupled to the outlet conduit of the cooling system; and a third
conduit having a proximal end of the elongate member disposed
therein.
31. The microwave treatment system according to claim 30, wherein
the inlet and outlet conduits of the cooling system extend through
the first and second longitudinal channels of the dielectric
material and are coupled to the first and second conduits of the
connecting hub.
32. The microwave treatment system according to claim 31, wherein
the proximal end of the elongate member includes: a first aperture
extending transversely from an outer surface of the elongate member
to the first longitudinal channel of the dielectric material; and a
second aperture extending transversely from the outer surface of
the elongate member to the second longitudinal channel of the
dielectric material.
33. The microwave treatment system according to claim 32, wherein
the inlet conduit of the cooling system includes an inlet curved
portion extending from the first longitudinal channel of the
dielectric material, through the first aperture, and into the first
conduit of the connecting hub, and the outlet conduit of the
cooling system includes an outlet curved portion extending from the
second longitudinal channel of the dielectric material, through the
second aperture, and into the second conduit of the connecting
hub.
34. The microwave treatment system according to claim 28, further
comprising a penetrating member supported at a distal end of the
elongate member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 12/395,034 filed on Feb. 27, 2009,
which claims the benefit of and priority to U.S. Provisional
Application Ser. No. 61/033,196 filed on Mar. 3, 2008, the entire
contents of each of which are incorporated by reference herein.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates generally to microwave
antennas for use in therapeutic or ablative tissue treatment
applications. More particularly, the present disclosure relates to
devices and methods for regulating, maintaining, and/or controlling
the temperature of microwave antennas used in such treatment
applications.
[0004] 2. Background of the Related Art
[0005] Many procedures and devices employing microwave technology
are well known for their applicability in the treatment,
coagulation, and targeted ablation of tissue. During such
procedures, a microwave probe antenna of the monopole, dipole, or
helical variety, as is conventional in the art, is typically
advanced into the patient, either laparoscopically or
percutaneously, to reach target tissue.
[0006] Following introduction of the microwave probe, microwave
energy is transmitted to the target tissue, which may cause the
outer surface of the antenna to sometimes reach unnecessarily high
temperatures via ohmic heating. Additionally, or alternatively,
losses in the feedline, through which energy is communicated to the
antenna from a power source, may contribute to heating in the
antenna. When exposed to such temperatures, the treatment site, as
well as the surrounding tissue, may be undesirably effected.
[0007] To prevent unnecessarily high temperatures, and the
corresponding undesirable effects upon the tissue, several
different cooling methodologies are conventionally employed. For
example, microwave probes may include external cooling jackets.
However, employing these jackets increases the overall size, i.e.,
the gauge size of the instrument, and consequently, the
invasiveness of the procedure. As such, there exists a continuing
need in the art for an improved microwave tissue treatment device
that includes a cooling system to avoid the realization of
unnecessarily high temperatures during treatment, as well as the
gauge size of the device, and thereby minimize undesirable effects
on the tissue.
SUMMARY
[0008] In one aspect of the present disclosure, a microwave tissue
treatment device for the therapeutic treatment or ablation of
tissue is disclosed. The microwave tissue treatment device includes
an antenna assembly having proximal and distal ends. The antenna
assembly includes an elongate member, an outer conductor positioned
within the elongate member, a dielectric material disposed within
the outer conductor and defining a lumen and one or more
longitudinally extending channels, an inner conductor including a
distal radiating section and being at least partially disposed
within the lumen, a sealing barrier disposed adjacent a distal end
of the outer conductor, a radiating portion, and a cooling
system.
[0009] The radiating portion is disposed adjacent the sealing
barrier, and includes the radiating section of the inner conductor
as well as a sheath with proximal and distal ends that is at least
partially disposed about the radiating section to define at least
one cavity. The at least one cavity may include two or more
regions, e.g., proximal, intermediate, and distal regions. In one
embodiment, the regions of the cavity may be at least partially
defined by one or more baffle members that are disposed within the
cavity. Additionally, the baffle member(s) will also define, at
least partially, two or more axial dimensions within the
cavity.
[0010] The cooling system includes inlet and outlet conduits that
are configured and dimensioned to circulate a fluid through the
antenna assembly. In one embodiment of the present disclosure, the
fluid may be a heat dissipative fluid that is selected from the
group consisting of water, saline, ammonium chloride, sodium
nitrate, and potassium chloride. The inlet and outlet conduits are
at least partially disposed within the channel or channels of the
dielectric material, and are in communication with the at least one
cavity such that at least a portion of the radiating section is in
contact with the fluid.
[0011] It is envisioned that the channel(s) extending through the
dielectric material may include at least a first channel and a
second channel. In one embodiment, the inlet member(s) may be at
least partially disposed in the first channel, and the outlet
member(s) may be at least partially disposed in the second
channel.
[0012] It is further envisioned that the microwave tissue treatment
device may also include a penetrating member that is disposed at
the distal end of the antenna assembly. The antenna assembly may
further include a connecting hub that is positioned proximally of
the sealing barrier and at least partially about the elongate
member. The connecting hub includes at least one conduit that is
configured and dimensioned to receive the inlet and outlet
member(s) of the cooling system.
[0013] In one embodiment of the antenna assembly, the outer
conductor may include one or more apertures that are configured and
dimensioned to receive the inlet and outlet member(s) of the
cooling system. Additionally, or alternatively, the microwave
tissue treatment may also include at least one temperature sensor
that is operatively connected to the radiating section.
[0014] In another aspect of the present disclosure, an improved
microwave tissue treatment device is disclosed. The improved
microwave tissue treatment device includes an outer conductor, an
inner conductor with a radiating section, and a radiating portion
that includes the radiating section of the inner conductor and a
sheath that is at least partially disposed thereabout to define at
least one cavity. The device also includes a cooling system with
inlet and outlet conduits that are in fluid communication with the
radiating section, and a dielectric material that is disposed
within the outer conductor. The dielectric material includes a
lumen and one or more channels that extend therethrough. The lumen
extending through the dielectric material is configured and
dimensioned to at least partially receive at least a portion of the
inner conductor, and the channel(s) extending through the
dielectric material are configured and dimensioned to at least
partially receive the inlet and outlet conduits.
[0015] In one embodiment, the cooling system includes first and
second channels that extend longitudinally through the dielectric
material. The first and second channels at least partially
accommodate the inlet and outlet conduits, respectively.
[0016] In another embodiment, the at least one cavity defined by
the sheath may include at least two regions. In this embodiment,
the improved microwave tissue treatment may further including one
or more baffle members that are disposed within the at least one
cavity to thereby divide the cavity into at least two regions.
[0017] In yet another aspect of the present disclosure, a method of
cooling a microwave antenna including an inner conductor, an outer
conductor, and a dielectric material is disclosed. The disclosed
method includes the steps of (i) providing a cooling system with
one or more inlet and outlet conduits disposed within the
dielectric material and in fluid communication with the microwave
antenna; and (ii) circulating a cooling fluid through the cooling
system such that the cooling fluid is in fluid communication with
at least a portion of the inner conductor.
[0018] In alternative embodiments, the disclosed method may further
comprise the step of monitoring the temperature of the inner
conductor with at least one temperature sensor operatively
connected thereto, and/or regulating the circulation of the cooling
fluid with a pump that is in communication with the cooling
system.
[0019] These and other features of the presently disclosed
microwave tissue treatment device, and corresponding method of use,
will become more readily apparent to those skilled in the art from
the following detailed description of various embodiments of the
present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Various embodiments of the present disclosure are described
hereinbelow with references to the drawings, wherein:
[0021] FIG. 1 is a schematic illustration of a microwave tissue
treatment system including a microwave tissue treatment device, in
accordance with an embodiment of the present disclosure;
[0022] FIG. 2A is a transverse, cross-sectional view of a feedline
of the microwave tissue treatment device of FIG. 1, as taken
through 2A-2A of FIG. 1;
[0023] FIG. 2B is a longitudinal, cross-sectional view of a
proximal portion of the feedline of the microwave tissue treatment
device of FIG. 1, as taken through 2B-2B of FIG. 1;
[0024] FIG. 3 is a schematic, perspective view of a proximal
portion of an antenna assembly of the microwave tissue treatment
device of FIG. 1;
[0025] FIG. 4A is a schematic, perspective view of a connecting hub
for use with the antenna assembly of the microwave tissue treatment
device of FIG. 1;
[0026] FIG. 4B is a longitudinal, cross-sectional view of the
connecting hub, as taken through 4B-4B of FIG. 3;
[0027] FIGS. 5A-5C are transverse, cross-sectional views of various
embodiments of a dielectric for use in the microwave tissue
treatment device of FIG. 1;
[0028] FIG. 6 is a schematic, cross-sectional, perspective view of
a sealing barrier for use in the microwave tissue treatment device
of FIG. 1, as taken through 6-6 of FIG. 1;
[0029] FIGS. 7A-7F are schematic, cross-sectional, perspective
views of various embodiments of a radiating portion of the
microwave tissue treatment of FIG. 1, as taken through 6-6 of FIG.
1;
[0030] FIG. 8 is a schematic, cross-sectional view of distal and
radiating portions of a microwave tissue treatment device, in
accordance with an embodiment of the present disclosure;
[0031] FIG. 9 is a schematic, cross-sectional, perspective view of
distal and radiating portions of a microwave tissue treatment
device including a cooling system, in accordance with another
embodiment of the present disclosure;
[0032] FIG. 10 is a schematic, cross-sectional, perspective view of
an embodiment of distal and radiating portions of the microwave
tissue treatment device of FIG. 9;
[0033] FIG. 11 is a schematic, cross-sectional, perspective view of
distal and radiating portions of an antenna assembly of a microwave
tissue treatment device in accordance with another embodiment of
the present disclosure;
[0034] FIG. 12 is a schematic, cross-sectional, perspective view of
distal and radiating portions of an antenna assembly of a microwave
tissue treatment device in accordance with yet another embodiment
of the present disclosure; and
[0035] FIG. 13 is a schematic, cross-sectional, perspective view of
distal and radiating portions of an antenna assembly of a microwave
tissue treatment device in accordance with still another embodiment
of the present disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0036] Specific embodiments of the presently disclosed microwave
tissue treatment device, and corresponding method of use thereof,
will now be described in detail with reference to the foregoing
figures wherein like reference characters identify similar or
identical elements. In the drawings and in the description which
follows, the term "proximal" will refer to the end of the microwave
tissue treatment device, or component thereof, that is closest to
the clinician during proper use, while the term "distal" will refer
to the end that is furthest from the clinician, as is conventional
in the art.
[0037] Referring now to FIGS. 1-4B, a microwave tissue treatment
system 10 is disclosed. System 10 includes a microwave tissue
treatment device 20 having an antenna assembly 100 connected to a
power supply 40 through a feedline 60. Power supply 40 may be any
power generating device suitable for the intended purpose of
energizing tissue treatment device 20, e.g., a microwave or RF
generator. Microwave tissue treatment device 20 may include one or
more pumps 80, e.g., a peristaltic pump or the like, as a mechanism
for circulating a cooling or heat dissipative fluid through antenna
assembly 100, as described below.
[0038] Feedline 60 may range in length from about 7 feet to about
10 feet, but may be either substantially longer or shorter if
required in a particular application. Feedline 60 may be composed
of any suitable conductive lead capable of transferring an
electrical current to tissue treatment device 20. In the embodiment
seen in FIG. 2A, feedline 60 includes an elongate member 62
disposed about a coaxial cable having an inner conductor 64, an
outer conductor 66, and a dielectric 68 interposed therebetween.
The dielectric 68 includes respective proximal and distal portions
60a, 60b, and electrically separates and/or isolates the inner
conductor 64 from the outer conductor 66. Elongate member 62
includes respective proximal and distal ends 62a, 62b, and may be
any sleeve, tube, jacket, or the like formed of any conductive or
non-conductive material.
[0039] Proximal portion 60a of feedline 60 is disposed proximally
of antenna assembly 100 and is operatively connected to, or
connectable to, power supply 40. As seen in FIG. 2B, proximal
portion 60a includes and defines proximal portions 64a, 66a, and
68a of inner conductor 64, outer conductor 66, and dielectric 68,
respectively. Distal portion 60b (FIG. 1) of feedline 60 forms a
component of antenna assembly 100, and includes and defines
respective distal portions 64b, 66b, 68b of inner conductor 64,
outer conductor 66, and dielectric 68. Alternatively, however, it
is envisioned that the feedline 60 may be separable from, and
connectable to, the antenna assembly 100. Reference may be made to
commonly owned U.S. Pat. No. 7,311,703 to Turovskiy, et al., filed
Jan. 20, 2005, for further discussion of the structure of feedline
60.
[0040] The respective inner and outer conductors 64, 66 are each
formed, at least in part, of a conductive material or metal, such
as stainless steel, copper, or gold. In certain embodiments, the
respective inner and outer conductors 64, 66 of feedline 60 may
include a conductive or non-conductive substrate that is plated or
coated with a suitable conductive material. In contrast, dielectric
68 is formed of a material having a dielectric value and tangential
loss constant of sufficient value to electrically separate and/or
isolate the respective inner and outer conductors 64, 66 from one
another, including but not being limited to, expanded foam
polytetrafluoroethylene (PTFE), polymide, silicon dioxide, or
fluorpolymer. However, it is envisioned that dielectric 68 may be
formed of any non-conductive material capable of maintaining the
desired impedance value and electrical configuration between the
respective inner and outer conductors 64, 66. In addition, it is
envisioned that dielectric 68 may be formed from a combination of
dielectric materials.
[0041] Antenna assembly 100 (FIG. 1) of microwave tissue treatment
device 10 will now be discussed. Antenna assembly 100 includes a
proximal portion 110, a distal or radiating portion 120, a sealing
barrier 140 disposed therebetween, and a cooling system 180.
[0042] Proximal portion 110 of antenna assembly 100 includes a
connecting hub 160 and distal portion 60b of feedline 60. As seen
in FIGS. 4A-4B, connecting hub 160 defines a first conduit 162
configured and dimensioned to receive distal portion 60b (FIG. 1)
of feedline 60, additional conduits 164a, 164b configured and
dimensioned to receive respective inlet and outlet conduits 182,
184 of cooling system 180, which is discussed in detail below, and
one or more apertures 166 formed in an internal surface thereof
that are configured and dimensioned to receive inlet and outlet
conduits 182, 184, respectively. Connecting hub 160 may be formed
of any suitable material including, but not limited to, polymeric
materials.
[0043] Distal portion 68b of dielectric 68 defines a lumen 70 and a
series of channels 72a-72d disposed thereabout, each extending
through dielectric 68. Lumen 70 is configured and dimensioned to
receive distal portion 64b of the inner conductor 64, and channels
72a-72d are configured and dimensioned to receive the respective
inlet and outlet conduits 182, 184 of cooling system 180. Lumen 70
and channels 72a-72d may be formed in dielectric 68 through any
suitable manufacturing method including, but not limited to
extrusion, injection molding, or drilling.
[0044] Although the embodiment of the microwave tissue treatment
device 10 discussed with respect to FIGS. 1-5B is illustrated as
including a distal portion 68b of dielectric 68 with a single lumen
70 and four channels, i.e., channels 72a, 72b, 72c, and 72d, that
are substantially circular in cross-sectional configuration, it
should be appreciated that the number and/or configuration of the
lumen 70 and the channels extending through dielectric 68 may be
varied depending on the air/polymer/cooling fluid ratio to match
the desired impedance, e.g., 50 ohms. For example, lumen 70 and
channels 72a-72d may be present in any number suitable for the
intended purpose of accommodating the respective inlet and outlet
conduits 182, 184 of cooling system 180, and may exhibit any
suitable geometrical configuration, such as that seen in the
embodiment illustrated in FIG. 5C. With reference to FIGS. 5A and
5B in particular, it is envisioned that channels 72a-72d may be
oriented such that they are completely or partially defined within
the perimeter "P" of distal portion 68b of dielectric 68.
[0045] Referring now to FIGS. 1, 3, and 6, sealing barrier 140 will
be discussed. Sealing barrier 140 is disposed between the
respective proximal and radiating portions 110, 120 (FIG. 3) of
antenna assembly 100. Sealing barrier 140 has proximal and distal
ends 142, 144 (FIG. 6), respectively, and may be connected to
proximal portion 110 of antenna assembly 100 in any suitable manner
including, but not limited to, a snap-fit arrangement, adhesives,
or a screw-type fit. Sealing barrier 140 defines a lumen 146 and
one or more channels 148 that extend axially therethrough. Lumen
146 is adapted to at least partially receive distal portion 64b of
inner conductor 64, and channels 148 are adapted to at least
partially receive the respective inlet and outlet conduits 182, 184
of cooling system 180. Lumen 146 and channels 148 are respectively
aligned with lumen 70 and channels 72a-72d (only channels 72a and
72c being shown) formed in distal portion 68b of dielectric 68 such
that distal portion 64b of inner conductor 64 and the respective
inlet and outlet conduits 182, 184 of cooling system 180 may extend
into radiating portion 120 of antenna assembly 100.
[0046] Sealing barrier 140 may be formed of any biocompatible
material suitable for the intended purpose of preventing the escape
of fluids into the proximal portion 110 of antenna assembly 100, as
described below. Sealing barrier 140 may be formed either of a
conductive or non-conductive material, and may be either
substantially rigid or substantially non-rigid in character.
Sealing barrier 140 inhibits fluid from contacting both the inner
conductor 64b and the outer conductor 66b, thus substantially
reducing the likelihood of an electrical short. Additionally,
sealing barrier 140 serves as a dielectric break allowing for the
dipole construction of the microwave tissue treatment device 10
(FIG. 1).
[0047] Referring now to FIG. 7A, as discussed above, radiating
portion 120 of antenna assembly 100 is disposed adjacent distal end
144 of sealing barrier 140. Radiating portion 120 includes a
radiating section 122 of inner conductor 64, a sheath 124 that is
at least partially disposed thereabout, and a penetrating member
126 supported on a distal end 124b of sheath 124.
[0048] Radiating section 122 of inner conductor 64 serves to
transmit the microwave energy supplied by power supply 40 (FIG. 1)
to a target area or target tissue (not shown). Radiating section
122 defines an axial dimension "L" and a radial dimension "D". As
would be appreciated by one of ordinary skill in the art, by
varying the axial and radial dimensions of the radiating section
122, the amount of microwave energy that can be transmitted to the
target tissue therethrough can be regulated or controlled.
[0049] In one embodiment, as seen in FIG. 7A, radiating section 122
of inner conductor 64 may be entirely formed of a conductive
material. In an alternative embodiment, as seen in FIG. 7B,
radiating section 122 may only be partially formed of a conductive
material. In this embodiment, radiating section 122 includes one or
more conductive surfaces 150 disposed on a non-conductive substrate
152. Conductive surface, or surfaces, 150 may have a particular
pattern or distribution for focusing or dispersing the energy
transmitted into the radiating section 122. For example, conductive
surfaces 150 may only be present on one side, or in one particular
area or region of radiating section 122. Conductive surfaces 150
may be integrally formed with substrate 152, or may be fixedly or
removably attached thereto.
[0050] Referring back to FIG. 7A, sheath 124 has respective
proximal and distal ends 124a, 124b, and is disposed at least
partially about radiating section 122 in such a manner so as to
define a cavity 128. At its proximal end 124a, sheath 124 may be
fixedly, releasably, and/or slidably connected to sealing barrier
140, elongate member 62, or any other suitable surface of antenna
assembly 100 in any appropriate manner including, but not being
limited to, the use of welds or adhesives, as would be appreciated
by one skilled in the art. In the embodiment seen in FIG. 7A,
distal end 124b of sheath 124 is open and configured for coupling
to penetrating member 126 such that cavity 128 is defined by the
penetrating member 126, sheath 124, and sealing barrier 140. In
this embodiment, sheath 124 may be connected to penetrating member
126 in any suitable manner including, but not limited to, a
screw-type fit, as seen in FIG. 7A, via a snap-fit arrangement, or
through the use of adhesives.
[0051] In another embodiment, as seen in FIG. 7C, distal end 124b
of sheath 124 is closed or sealed such that cavity 128 is defined
by sheath 124 and sealing barrier 140 only.
[0052] In yet another embodiment, as seen in FIG. 7D, distal end
124b of sheath 124 is closed and formed integrally with penetrating
member 126 such that cavity 128 is defined by sheath 124, sealing
barrier 140, and penetrating member 126.
[0053] In still another embodiment, as best seen in FIG. 7E, a
distal-most tip 130 of radiating section 122 of inner conductor 64
extends beyond distal end 124b of sheath 124. In this embodiment,
penetrating member 126 may be connected directly to radiating
section 122.
[0054] As seen in FIG. 7F, sheath 124 may also be connected
directly to radiating section 122 of inner conductor 64 at its
distal-most tip 130. In this embodiment, penetrating member 126 is
connected either to sheath 124 or to radiating section 122.
[0055] With respect to each of the aforementioned embodiments,
sheath 124 may be formed of any biocompatible material suitable for
the intended purpose of retaining a fluid therein while allowing
for the dispersion of microwave energy. It is contemplated that the
sheath 124 may be formed, in whole or in part, of a substantially
rigid or a substantially non-rigid material. For example, in those
embodiments wherein the inner conductor 64b is electrically
connected to sheath 124, sheath 124 can be formed from stainless
steel. Additionally, the connection between penetrating member 126
may be either releasably or fixedly coupled with antenna assembly
100 in any suitable manner.
[0056] Referring now to FIG. 8, cavity 128 may include one or more
internal baffle members 132, 134 that divide radiating portion 120
into respective proximal, intermediate, and distal regions 120a,
120b, and 120c. Additionally, the baffle members 132, 134 act to
divide cavity 128 into respective proximal, intermediate, and
distal cells 128a, 128b, 128c, and radiating section 122 into
respective first, second, and third segments 122a, 122b, 122c.
Although the particular embodiment shown in FIG. 8 includes two
baffle members, any suitable number of baffle members may be
employed to divide radiating portion 120, cavity 128, and radiating
section 122 into any suitable number of regions, cells, and
segments, respectively.
[0057] Proximal cell 128a of cavity 128, and consequently, first
segment 122a of radiating section 122 of inner conductor 64,
exhibit a first axial dimension L.sub.1, and are defined by first
baffle member 132 and the location where proximal end 124a of the
sheath 124 meets sealing barrier 140. Intermediate cell 128b of
cavity 128, and consequently, second segment 122b of radiating
section 122 exhibit a second axial dimension L.sub.2, and are
defined by the location of first baffle member 132 and second
baffle member 134. Distal cell 128c of cavity 128 and third segment
122c of radiating section 122 exhibit a third axial dimension
L.sub.3, and are defined by the location of second baffle member
134 and distal end 126c of sheath 124.
[0058] First and second baffle members 132, 134, respectively,
serve not only to partially define the metes of the three cells
128a, 128b, 128c of cavity 128 defined by sheath 124, but also to
substantially prevent any co-mingling of fluid or fluids (not
shown) that may be circulated throughout each of the respective
proximal, intermediate, and distal regions 120a, 120b, 120c of the
radiating portion 120, as discussed in further detail herein
below.
[0059] With continued reference to FIG. 8, distal region 120c of
radiating portion 120 of antenna assembly 100 may comprise the area
of active heating during tissue treatment or ablation. It may be
desirable, therefore, to prevent the temperature in distal region
120c from reaching excessively high temperatures in order to
maintain optimal energy delivery and to maintain optimal thermal
therapy of the tissue. Intermediate region 120b may also become hot
due to ohmic and conductive heating from distal region 120c. Since
intermediate region 120b may be in contact with the tissue
surrounding the target site, it may be desirable to allow
intermediate region 120b to achieve a particular temperature
profile dependent upon the nature of the surgical procedure being
performed.
[0060] As an illustrative example, where coagulation of the
insertion tract may be desirable, the clinician may want to allow
intermediate region 120b of radiating portion 120 to attain a
particular predetermined temperature capable of creating a
coagulation effect in the insertion tract. In other applications,
it may also be desirable, to prevent the temperature in
intermediate region 120b from rising beyond a particular threshold
level to protect surrounding sensitive tissue structures from
undesired effects.
[0061] During use, proximal region 120a of radiating portion 120
may also come into contact with the skin or tissue of a patient. As
proximal region 120a may also be subject to ohmic and/or conductive
heating, it may be desirable to maintain the temperature of
proximal region 120a below a specific temperature, particularly in
percutaneous or laparoscopic procedures, to mitigate or
substantially prevent any undesired effects upon the patient's
tissue. In other procedures, such as in applications where lesions
are located deep within the tissue, it may be desirable to allow
the proximal region 120a to become heated to allow for the
coagulation of the insertion tract.
[0062] Referring now to FIG. 1 as well, the specific components and
features of the presently disclosed cooling system 180 reduce the
radial or transverse dimensions of antenna assembly 100, thereby
potentially improving the performance of the antenna assembly 100.
However, reducing the dimensions of antenna assembly 100 may
necessitate an increase in the amount of energy flowing through
antenna assembly 100 to achieve the same therapeutic effect that
could otherwise be achieved by using a larger, more conventional
antenna assembly and lower energy levels. The presently disclosed
cooling system 180 reduces the likelihood that the increased amount
of energy flowing through antenna assembly 100 will have negative
results, e.g., losses, overheating, and potential failure of
microwave tissue treatment device 20, and counteracts the impact of
any such results should they occur.
[0063] Referring now to FIGS. 1 and 9, cooling system 180 will be
discussed. Cooling system 180 is adapted to circulate a fluid "F",
either constantly or intermittently, throughout radiating portion
120 (FIG. 1) of antenna assembly 100. Fluid "F" may be a liquid,
e.g., water, saline, liquid chlorodifluoromethane, perfluorocarbon,
such as Fluorinert.RTM., distributed commercially by Minnesota
Mining and Manufacturing Company (3M), St. Paul, Minn., USA, or any
combination thereof. In various embodiments, gases, such as air,
nitrous oxide, nitrogen, carbon dioxide, etc., may be utilized as
an alternative to, or in conjunction with, any of the
aforementioned liquids. The composition of fluid "F" may be varied
depending upon the desired cooling rate and the desired impedance
of the feedline 60.
[0064] Cooling system 180 includes an inlet conduit 182 having a
proximal end 182a (FIG. 1) and a distal end 182b (FIG. 9), and an
outlet conduit 184 having a proximal end 184a (FIG. 1) and a distal
end 184b (FIG. 9). Proximal ends 182a, 184a of inlet and outlet
conduits 182, 184, respectively, are connected to, and are in fluid
communication with, pump 80 (FIG. 1), and distal ends 182b, 184b of
inlet and outlet conduits 182, 184, respectively, are in fluid
communication with cavity 128 (FIG. 9) defined by sheath 124. Inlet
and outlet conduits 182, 184, respectively, act in concert with
pump 80 to circulate fluid "F" through cavity 128, thereby cooling
radiating section 122 of inner conductor 64 (see, e.g., FIG. 2A).
Cooling system 180 may include any number of inlet and outlet
conduits 182, 184 suitable for the intended purpose of circulating
dissipative fluid "F" throughout cavity 128.
[0065] With additional reference to FIGS. 3 and 4A-4B, the
respective inlet and outlet conduits 182, 184 extend from pump 80
and enter conduits 164a, 164b of connecting hub 160. The respective
inlet and outlet conduits 182, 184 pass through elongate member 62
and enter channels 72a-72d formed in distal portion 68b of
dielectric 68 through apertures 166 formed in connecting hub 160.
The respective inlet and outlet conduits 182, 184 extend distally
through channels 148 (FIG. 9) formed in sealing barrier 140 and
into radiating portion 120 (FIG. 1) of antenna assembly 100,
thereby facilitating the circulation of fluid "F" within the
radiating portion 120
[0066] Including a cooling system 180, e.g., the respective inlet
and outlet conduits 182, 184, that extends through the dielectric
68, as opposed a cooling system that includes an external cooling
chamber that is positioned about the antenna assembly 100, creates
a size reduction benefit. That is, by eliminating the need for an
external cooling chamber, the transverse outer dimension of the
outer conductor 66b will constitute the transverse outer dimension
of the antenna assembly 100. This allows for the employment of
larger inner and outer conductors 64b, 66b, respectively, which
reduces loss effects, without increasing the overall transverse
dimension of the antenna assembly 100.
[0067] As seen in FIG. 10, in one embodiment, the number of
respective inlet and outlet conduits 182, 184 corresponds to the
number of regions, segments, and cells of the radiating portion 120
of antenna assembly 100, radiating section 122 of inner conductor
64, and cavity 128, respectively. In particular, inlet and outlet
conduits 182', 184' circulate fluid "F" throughout proximal cell
128a of cavity 128 such that fluid "F" may contact proximal segment
122a of radiating section 122, and thereby cool proximal region
120a of radiating portion 120 of assembly 100. In likewise fashion,
respective inlet and outlet conduits 182'', 184'' circulate fluid
"F" throughout intermediate cell 128b of cavity 128 such that fluid
"F" may contact intermediate segment 122b of radiating section 122,
and thereby cool intermediate region 120b of radiating portion 120
of antenna assembly 100, and respective inlet and outlet conduits
182''', 184''' circulate fluid "F" throughout distal cell 128c of
cavity 128 such that fluid "F" may contact distal segment 122c of
radiating section 122, and thereby cool distal region 120c of
radiating portion 120 of antenna assembly 100. While FIG. 10
depicts each cell 128a-128c in contact with fluid "F," the present
disclosure also envisions, the alternative, that fluid "F" may not
be circulated through one or more of cells 128a-128c.
[0068] Referring still to FIG. 10, upon entering proximal cell 128a
through inlet conduit 182', i.e., in the direction of arrows "A",
fluid "F" comes into direct contact with proximal segment 122a of
radiating section 122 of inner conductor 64, allowing for the
direct convective cooling thereof. As the fluid "F" cools proximal
segment 122a, pump 80 (FIG. 1) removes fluid "F" from proximal cell
128a, in the direction of arrows "B", through outlet conduit 184'.
In so doing, the heat generated by proximal segment 122a during the
operation of antenna assembly 100 may be regulated and/or
dissipated. Accordingly, the temperature of proximal region 120a of
radiating portion 120 may be controlled.
[0069] As with proximal cell 128a, fluid "F" may be circulated into
and out of intermediate cell 128b by pump 80 (FIG. 1) through inlet
and outlet conduits 182'', 184'', respectively, thereby dissipating
the heat generated by the intermediate segment 122b during the
operation of antenna assembly 100 through fluid "F".
[0070] Similarly, fluid "F" may be circulated into and out of the
distal cell 128c by pump 80 (FIG. 1) through inlet and outlet
conduits 182''', 184''', respectively, thereby dissipating the heat
generated by the distal segment 122c during the operation of
antenna assembly 100 through fluid "F".
[0071] To circulate fluid "F" through proximal cell 128a of cavity
128, inlet and outlet conduits 182', 184' pass through
corresponding channels 148 (FIGS. 6, 9) in sealing barrier 140. To
circulate fluid "F" through intermediate cell 128b, inlet and
outlet conduits 182'', 184'' pass through channels 148, as well as
through apertures 136 in first baffle member 132. To circulate
fluid "F" through distal cell 128c, inlet and outlet conduits
182''', 184''' pass through channels 148, through apertures 136 in
first baffle member 132, through intermediate cell 128b, and
finally through apertures 136 in second baffle member 134.
[0072] Sealing barrier 140, first baffle member 132, and second
baffle member 134 may each include seal members (not shown)
respectively associated with channels 148 and apertures 136 to
substantially prevent fluid "F" from commingling between cells
128a-128c of cavity 128, and the seal members may be any member
suitable for this intended purpose including but not being limited
to seals, gaskets, or the like. The seal members may be formed of
any suitable material, including but not being limited to, a
polymeric material.
[0073] Referring still to FIG. 10, given the desirability of
controlling heating and temperature regulation within the
individual segments 122a-122c of radiating section 122 (FIG. 9) of
inner conductor 64 (see, e.g., FIG. 2A), and the corresponding
regions 120a-120c of radiating portion 120 of antenna assembly 100,
the axial locations of baffle members 132, 134 within cavity 128
may be varied as desired or necessary such that the respective
axial dimensions L.sub.1, L.sub.2, and L.sub.3 of the proximal,
intermediate, and distal cells 128a-128c of cavity 128 may also be
varied. In varying the axial length of a particular cell of cavity
128, the overall volume of that cell may be varied, and
consequently, so too may the volume of fluid "F" circulated
therein. As would be appreciated by one of ordinary skill in the
art, an inverse relationship exists between the volume of fluid "F"
within a particular cell of cavity 128 and the temperature of the
corresponding region of radiating portion 120, in that as the
volume of fluid "F" is increased, the temperature of the region
will decrease.
[0074] Baffle members 132, 134 may be located at any suitable or
desired point within the cavity 128. In one embodiment, baffle
members 132, 134 may be positioned such that the respective first,
second and third axial dimensions, L.sub.1, L.sub.2, and L.sub.3 of
proximal, intermediate, and distal cells 128a-128c are
substantially equivalent. In another embodiment, baffle members
132, 134 are positioned such that the first axial dimension L.sub.1
of proximal cell 128a is greater than the respective second and
third axial dimensions L.sub.2 and L.sub.3 of intermediate and
distal cells 128b, 128c. In yet another embodiment, baffle members
132, 134 may be positioned such that the third axial dimension
L.sub.3 of distal cell 128c is greater than the respective first
and second axial dimensions L.sub.1 and L.sub.2 of proximal and
intermediate cells 128a, 128b. In alternative embodiments, baffle
members 132, 134 may be located such that the overall volume of the
cavity 128 may be distributed amongst any individual cells thereof
in any suitable manner.
[0075] With reference now to FIG. 11, in another embodiment,
proximal, intermediate, and distal cells 128a, 128b, 128c of cavity
128 define respective first, second, and third radial dimensions
D.sub.1, D.sub.2, and D.sub.3. As shown, radial dimension D.sub.1
is greater than radial dimension D.sub.2, which is in turn greater
than radial dimension D.sub.3. However, the respective first,
second, and third radial dimensions D.sub.1, D.sub.2, and D.sub.3
may also be substantially equivalent.
[0076] The respective radial dimensions D.sub.1, D.sub.2, and
D.sub.3 of proximal, intermediate, and distal cells 128a, 128b,
128c may be varied in any suitable manner so as to regulate the
volume thereof, and consequently, the volume of fluid "F" that may
be circulated therethrough. By varying the volume of fluid "F"
circulated through each cell 128a-128c of cavity 128, the
temperature of each corresponding region 120a-120c of radiating
portion 120 of antenna assembly 100 may be substantially regulated,
as discussed above.
[0077] As seen in FIG. 12, in another embodiment, cavity 128
defines a radial dimension D that is varied in a continuously
decreasing manner over the axial length thereof, such that a
generally tapered profile is exhibited. The tapered profile
exhibited in this embodiment may also be applied to any of the
embodiments disclosed herein above.
[0078] FIG. 13 illustrates yet another embodiment in which antenna
assembly 100 includes one or more temperature sensors 190 adapted,
coupled, or operatively connected to segments 122a-122c of
radiating section 122 of inner conductor 64. Temperature sensors
190 may be used to monitor any fluctuation in temperature in
regions 120a-120c of radiating portion 120. It may be desirable to
monitor the temperature of the radiating portion 120, and/or the
tissue that may come into contact therewith, in an effort to guard
against over heating and/or any unintended therapeutic effects on
the tissue. This may be particularly useful in applications where
microwave energy is used for treating or ablating tissue around the
radiating portion. In alternative embodiments, temperature sensors
190 may be adapted, coupled, operatively connected, or incorporated
into antenna assembly 100 at any suitable location, including, but
not being limited to on sheath 124. Temperature sensors 190 may be
located on or within the sheath 124 using any conventional means,
e.g., adhesives. Temperature sensors 190 may also be located on one
or more baffle members, e.g., baffle member 132, 134, if any.
Temperature sensors 190 may be configured and adapted for
electrical connection to a power supply 40 (FIG. 1).
[0079] Temperature sensors 190 may be a semiconductor-based sensor,
a thermister, a thermal couple or other temperature sensor that
would be considered as suitable by one skilled in the art. An
independent temperature monitor (not shown) may be connected to the
temperature sensor, or alternatively, power supply 40 (FIG. 1) may
include an integrated temperature monitoring circuit (not shown),
such as one described in U.S. Pat. No. 5,954,719, to modulate the
microwave power output supplied to antenna assembly 100. Other
physiological signals, e.g. EKG, may also be monitored by
additional medical instrumentation well known to one skilled in the
art and such data applied to control the microwave energy delivered
to the antenna assembly 100.
[0080] A closed loop control mechanism, such as a feedback
controller with a microprocessor, may be implemented for
controlling the delivery of energy, e.g., microwave energy, to the
target tissue based on temperature measured by temperature sensors
190.
[0081] The above description, disclosure, and figures should not be
construed as limiting, but merely as exemplary of particular
embodiments. It is to be understood, therefore, that the disclosure
is not limited to the precise embodiments described, and that
various other changes and modifications may be effected therein by
one skilled in the art without departing from the scope or spirit
of the disclosure. Additionally, persons skilled in the art will
appreciate that the features illustrated or described in connection
with one embodiment may be combined with those of another, and that
such modifications and variations are also intended to be included
within the scope of the present disclosure.
* * * * *