INTRACOOLED PERCUTANEOUS MICROWAVE ABLATION PROBE
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.
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.
BACKGROUND1. Technical Field
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.
2. Background of the Related Art
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.
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.
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.
SUMMARYIn 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein:
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.
Referring now to
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
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
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.
Antenna assembly 100 (
Proximal portion 110 of antenna assembly 100 includes a connecting hub 160 and distal portion 60b of feedline 60. As seen in
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.
Although the embodiment of the microwave tissue treatment device 10 discussed with respect to
Referring now to
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 (
Referring now to
Radiating section 122 of inner conductor 64 serves to transmit the microwave energy supplied by power supply 40 (
In one embodiment, as seen in
Referring back to
In another embodiment, as seen in
In yet another embodiment, as seen in
In still another embodiment, as best seen in
As seen in
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.
Referring now to
Proximal cell 128a of cavity 128, and consequently, first segment 122a of radiating section 122 of inner conductor 64, exhibit a first axial dimension L1, 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 L2, 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 L3, and are defined by the location of second baffle member 134 and distal end 126c of sheath 124.
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.
With continued reference to
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.
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.
Referring now to
Referring now to
Cooling system 180 includes an inlet conduit 182 having a proximal end 182a (
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 (
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.
As seen in
Referring still to
As with proximal cell 128a, fluid “F” may be circulated into and out of intermediate cell 128b by pump 80 (
Similarly, fluid “F” may be circulated into and out of the distal cell 128c by pump 80 (
To circulate fluid “F” through proximal cell 128a of cavity 128, inlet and outlet conduits 182′, 184′ pass through corresponding channels 148 (
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.
Referring still to
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, L1, L2, and L3 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 L1 of proximal cell 128a is greater than the respective second and third axial dimensions L2 and L3 of intermediate and distal cells 128b, 128c. In yet another embodiment, baffle members 132, 134 may be positioned such that the third axial dimension L3 of distal cell 128c is greater than the respective first and second axial dimensions L1 and L2 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.
With reference now to
The respective radial dimensions D1, D2, and D3 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.
As seen in
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 (
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.
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.
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.
Type: Application
Filed: Feb 24, 2015
Publication Date: Jun 18, 2015
Inventors: KENLYN S. BONN (LAKEWOOD, CO), STEVEN E. BUTCHER (BERTHOUD, CO)
Application Number: 14/630,317