Microwave antenna

Information

  • Patent Grant
  • 8251987
  • Patent Number
    8,251,987
  • Date Filed
    Thursday, August 28, 2008
    16 years ago
  • Date Issued
    Tuesday, August 28, 2012
    12 years ago
Abstract
According to one aspect of the present disclosure, a microwave antenna assembly is disclosed. The antenna assembly includes a feedline having an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna having a proximal portion and a distal portion. The antenna assembly also comprises a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion. The chamber is adapted to circulate coolant fluid therethrough. The antenna assembly further includes a connection hub having cable connector coupled to the feedline, an inlet fluid port and an outlet fluid port. The connection hub includes a bypass tube configured to provide for flow of the coolant fluid from the cable connector directly to the outlet fluid port.
Description
BACKGROUND

1. Technical Field


The present disclosure relates generally to microwave antennas used in tissue ablation procedures. More particularly, the present disclosure is directed to a microwave antenna having a coolant assembly for circulating a dielectric coolant fluid through the microwave antenna.


2. Background of Related Art


Treatment of certain diseases requires destruction of malignant tissue growths (e.g., tumors). It is known that tumor cells denature at elevated temperatures that are slightly lower than temperatures injurious to surrounding healthy cells. Therefore, known treatment methods, such as hyperthermia therapy, heat tumor cells to temperatures above 41° C., while maintaining adjacent healthy cells at lower temperatures to avoid irreversible cell damage. Such methods involve applying electromagnetic radiation to heat tissue and include ablation and coagulation of tissue. In particular, microwave energy is used to coagulate and/or ablate tissue to denature or kill the cancerous cells.


Microwave energy is applied via microwave ablation antennas that penetrate tissue to reach tumors. There are several types of microwave antennas, such as monopole and dipole in which microwave energy radiates perpendicularly from the axis of the conductor. A monopole antenna includes a single, elongated microwave conductor whereas a dipole antenna includes two conductors. In a dipole antenna, the conductors may be in a coaxial configuration including an inner conductor and an outer conductor separated by a dielectric portion. More specifically, dipole microwave antennas may have a long, thin inner conductor that extends along a longitudinal axis of the antenna and is surrounded by an outer conductor. In certain variations, a portion or portions of the outer conductor may be selectively removed to provide more effective outward radiation of energy. This type of microwave antenna construction is typically referred to as a “leaky waveguide” or “leaky coaxial” antenna.


Conventional microwave antennas have a narrow operational bandwidth, a wavelength range at which optimal operational efficiency is achieved, and hence, are incapable of maintaining a predetermined impedance match between the microwave delivery system (e.g., generator, cable, etc.) and the tissue surrounding the microwave antenna. More specifically, as microwave energy is applied to tissue, the dielectric constant of the tissue immediately surrounding the microwave antenna decreases as the tissue is cooked. The drop causes the wavelength of the microwave energy being applied to tissue to increase beyond the bandwidth of the antenna. As a result, there is a mismatch between the bandwidth of conventional microwave antenna and the microwave energy being applied. Thus, narrow band microwave antennas may detune hindering effective energy delivery and dispersion.


SUMMARY

According to one aspect of the present disclosure, a microwave antenna assembly is disclosed. The antenna assembly includes a feedline having an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna having a proximal portion and a distal portion. The antenna assembly also comprises a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion. The chamber is adapted to circulate coolant fluid therethrough. The antenna assembly further includes a connection hub having cable connector coupled to the feedline, an inlet fluid port and an outlet fluid port. The connection hub includes a bypass tube configured to provide for flow of the coolant fluid from the cable connector directly to the outlet fluid port.


According another aspect of the present disclosure, a microwave antenna assembly is disclosed. The antenna assembly includes a feedline having an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna having a proximal portion and a distal portion. The antenna assembly also comprises a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion. The chamber is adapted to circulate coolant fluid therethrough. The antenna assembly further includes a three-branch connection hub including a first branch having a cable connector coupled to the feedline at a junction point, a second branch having an outlet port, a third branch having an inlet port, and a bypass tube in fluid communication with a proximal end of the first branch and the outlet port, wherein one end of the bypass tube is in proximity with the junction point to provide for flow of the coolant fluid therethrough.


A method for manufacturing a microwave antenna assembly is also contemplated by the present disclosure. The antenna assembly includes a feedline including an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna having a proximal portion and a distal portion. The method includes the step of enclosing the feedline and the radiating portion in a sheath to define a chamber around the feedline and the radiating portion. The chamber is adapted to circulate coolant fluid therethrough. The method also includes the step of coupling a three-branch connection hub to the feedline and the sheath. The three-branch connection hub including a first branch having a cable connector coupled to the feedline at a junction point, a second branch having an outlet port, a third branch having an inlet port. A step of interconnecting a proximal end of the first branch and the outlet port via a bypass tube is also provided by the method. One end of the bypass tube is in proximity with the junction point to provide for flow of the coolant fluid therethrough





BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which:



FIG. 1 is a schematic diagram of the microwave ablation system according to an embodiment of the present disclosure;



FIG. 2 is a perspective, internal view of the microwave antenna assembly according to the present disclosure;



FIGS. 3 and 4 are enlarged, cross-sectional views of a portion of the microwave antenna assembly of FIG. 1;



FIG. 5 is a side view of an interchangeable tip (or a sheath and a tip assembly) for use with the microwave antenna assembly of FIG. 1;



FIG. 6 is a schematic, top view of a connection hub of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIG. 7 a cross-sectional view of a series of inflow tubes of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIG. 8 is a topside view of a proximal portion of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIG. 9 is a side view of a proximal end of the feedline of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIG. 10 is a side view of a cable connector of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIG. 11 is a top view of a connection hub of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIGS. 12A and B are perspective and side views of the connection hub of the microwave antenna assembly of FIG. 1 according to the present disclosure;



FIG. 13 is a top view of a connection hub of the microwave antenna assembly of FIG. 1 with parts disassembled according to the present disclosure;



FIG. 14 is a top view of a connection hub of the microwave antenna assembly of FIG. 1 according to one embodiment of the present disclosure; and



FIG. 15 is a top view of a connection hub of the microwave antenna assembly of FIG. 1 with parts disassembled according to one embodiment of the present disclosure.





DETAILED DESCRIPTION

Particular embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.



FIG. 1 shows a microwave ablation system 10 that includes a microwave antenna assembly 12 coupled to a microwave generator 14 via a flexible coaxial cable 16. The generator 14 is configured to provide microwave energy at an operational frequency from about 500 MHz to about 5000 MHz although other suitable frequencies are also contemplated.


The antenna assembly 12 includes a radiating portion 18 connected by feedline 20 (or shaft) to the cable 16. More specifically, the antenna assembly 12 is coupled to the cable 16 through a connection hub 22 having an outlet fluid port 30 and an inlet fluid port 32 that are connected in fluid communication with a sheath 38. The sheath 38 encloses radiating portion 18 and feedline 20 allowing a coolant fluid 37 to circulate from ports 30 and 32 around the antenna assembly 12. The ports 30 and 32 are also coupled to a supply pump 34 that is, in turn, coupled to a supply tank 36 via supply line 86. The supply pump 34 may be a peristaltic pump or any other suitable type. The supply tank 36 stores the coolant fluid 37 and in one embodiment, may maintain the fluid at a predetermined temperature. More specifically, the supply tank 36 may include a coolant unit that cools the returning liquid from the antenna assembly 12. In another embodiment, the coolant fluid 37 may be a gas and/or a mixture of fluid and gas.



FIG. 2 illustrates the radiating portion 18 of the antenna assembly 12 having a dipole antenna 40. The dipole antenna 40 is coupled to the feedline 20 that electrically connects antenna assembly 12 to the generator 14. As shown in FIGS. 3-4, the feedline 20 includes an inner conductor 50 (e.g., wire) surrounded by an inner insulator 52, which is surrounded by an outer conductor 56 (e.g., cylindrical conducting sheath). The inner and outer conductors 50 and 56 respectively, may be constructed of copper, gold, stainless steel or other conductive metals with similar conductivity values. The metals may be plated with other materials, e.g., other conductive materials, to improve their properties, e.g., to improve conductivity or decrease energy loss, etc. In one embodiment, the feedline 20 may be formed from a coaxial semi-rigid or flexible cable having a wire with a 0.047″ outer diameter rated for 50 Ohms.


The dipole antenna 40 includes a proximal portion 42 and a distal portion 44 interconnected at a feed point 46. The distal portion 44 and the proximal portion 42 may be either balanced (e.g., of equal lengths) or unbalanced (e.g., of unequal lengths). The proximal portion 42 is formed from the inner conductor 50 and the inner insulator 52 which are extended outside the outer conductor 56, as shown best in FIG. 4. In one embodiment, in which the feedline 20 is formed from a coaxial cable, the outer conductor 56 and the inner insulator 52 may be stripped to reveal the inner conductor 50, as shown in FIG. 3.



FIG. 3 illustrates the distal portion 44 attached to the proximal portion 42. The distal portion 44 may be soldered to the inner conductor 50 of the proximal portion 42 to establish electromechanical contact therebetween. A portion of the distal end of the inner conductor 50 is inserted into the distal portion 44 such that a dipole feed gap “G” remains between the proximal and distal portions 42 and 44 at the feed point 46. The gap “G” may be from about 1 mm to about 3 mm. In one embodiment, the gap “C” may be thereafter filled with a dielectric material at the feed point 46. In another embodiment, the inner insulator 52 is extended into the feed point 46. The dielectric material may be polytetrafluoroethylene (PTFE), such as Teflon® sold by DuPont of Wilmington, Del. In another embodiment, as shown in FIG. 3, the gap “G” may be coated with a dielectric seal coating as discussed in more detail below.


With reference to FIGS. 2 and 4, the antenna assembly 12 also includes a choke 60. The choke 60 is disposed around the feedline 20 and includes an inner dielectric layer 62 and an outer conductive layer 64. The choke 60 may be a quarter-wavelength shorted choke and is shorted to the outer conductor 56 of the feedline 20 at the proximal end (not illustrated) of the choke 60 by soldering or other suitable methods. In one embodiment, the dielectric layer 62 is formed from a fluoropolymer, such as tetrafluorethylene, perfluorpropylene, and the like, and has a thickness of about 0.005 inches. The dielectric of dielectric layer 62 may extend past the choke conductor layer 64 toward the distal end of the assembly 12, as shown in FIG. 2.


Since the radiating portion 18 and the feedline 20 are in direct contact with the coolant fluid 37 these components of the assembly 12 are sealed by a protective sleeve 63 (FIG. 3) to prevent any fluid seeping therein. This may be accomplished by applying any type of melt-processible polymers using conventional injection molding and screw extrusion techniques. In one embodiment, a sleeve of fluorinated ethylene propylene (FEP) shrink wrap may be applied to the entire assembly 12, namely the feedline 20 and the radiating portion 18, as shown in FIGS. 3 and 4. The protective sleeve 63 is then heated to seal the feedline 20 and radiating portion 18. The protective sleeve 63 prevents any coolant fluid 37 from penetrating into the assembly 12. The protective sleeve 63 may be applied either prior to or after applying the outer conductive layer 64. In addition, protective sleeve 63 may also be applied at the point where the inner conductor 50 and the inner insulator 52 are extended past the outer conductor 56, thereby creating a vacuum 53 as shown in FIG. 3.


Assembly 12 also includes a tip 48 having a tapered end 24 that terminates, in one embodiment, at a pointed end 26 to allow for insertion into tissue with minimal resistance at a distal end of the radiating portion 18. In those cases where the radiating portion 18 is inserted into a pre-existing opening, tip 48 may be rounded or flat.


The tip 48, which may be formed from a variety of heat-resistant materials suitable for penetrating tissue, such as metals (e.g., stainless steel) and various thermoplastic materials, such as poletherimide, polyamide thermoplastic resins, an example of which is Ultem® sold by General Electric Co. of Fairfield, Conn. The tip 48 may be machined from various stock rods to obtain a desired shape. The tip 48 may be attached to the distal portion 44 using various adhesives, such as epoxy seal. If the tip 48 is metal, the tip 48 may be soldered to the distal portion 44.



FIG. 5 illustrates various shapes and forms of the tip 48, namely a stainless steel tip 48a and a dielectric tip 48b. Both tips 48a and 48b include an insertion base 51 having an external diameter that is smaller than diameter of the tips 48a and 48b allowing for easier insertion into the sheath 38. This configuration also provides for a better seal between the tip 48 and the sheath 38. The sheath 38 encloses the feedline 20, the radiating portion 18 from the tip 48 to the base 81 (FIG. 6). The sheath 38 is also secured to the base 81 of the connection hub 22 and the tip 48 such that the sheath 38 is in fluid communication with the connection hub 22 and defines a chamber 89 (FIG. 3) between the base 81 and the tip 48. The coolant fluid 37 is supplied by the pump 34 and is circulated in the chamber 89 between the radiating portion 18, the feedline 20 and the sheath 38. The sheath 38 may be any type of rigid tube, such as a catheter manufactured from polyimide and other types of polymers. The sheath 38 may be assembled by initially securing the tip 48 to the distal end of the sheath 38 and then inserting the combined sheath and tip assembly onto the assembly 12.


The assembly 12 also includes the connection hub 22, as shown in more detail in FIG. 6. The connection hub 22 includes a cable connector 79 and fluid ports 30 and 32. The connection hub 22 may include a three-branch luer type connector 72, with a first branch 74 being used to house the cable connector 79 and the second and third branches 76 and 78 to house the outlet and inlet fluid ports 30 and 32, respectively. In one embodiment, the connection hub 22 may include only the first branch 74 or two of the branches 74, 76, 78 and have the fluid ports 30 and 32 disposed directly on the first branch 74.


The connection hub 22 also includes a base 81 disposed at a distal end of the first branch 74. More than one inflow 86 and outflow 88 tube may be used. The outflow tube 88 is coupled to the second branch 76 and is in fluid communication with the bypass tube 80 through the second branch 76. In one embodiment, the assembly 12 includes one or more inflow tubes 86a and 86b that are fed through the third branch 78 as shown in FIG. 6.


In one embodiment, the second and third branches 76 and 78 may include various types of female and/or male luer connectors adapted to couple inflow and outflow tubes 86 and 88, respectively, from the pump 34 to the assembly 12. FIG. 7 shows the assembly 12 including two inflow tubes 86a and 86b. The inflow tubes 86a and 86b may be any type of flexible tube having an external diameter sufficient to fit inside a chamber 89 between the feedline 20 and the sheath 38. The inflow tubes 86a and 86b are inserted through the inlet fluid port 32. More specifically, as illustrated in FIG. 8, a female connector 102 may be coupled to the inlet port 32 either directly or to an intermediate male luer connector 104. The distal ends of the tubes 86a and 86b are inserted through an internal support member 103 of the female connector 102, which secures the tubes 86a and 86b thereto. The female and male connectors 102 and 104 allow for easy coupling of the assembly 12 to the coolant fluid system. The inflow tubes 86a and 86b may be secured to the third branch 78 via a glue plug 105, which may be formed by flowing glue into the third branch 78 and curing the glue via an ultraviolet source or other way known in the art.


The inflow tube 86a is inserted into the distal end of the distal portion 44 and the inflow tube 86b is inserted at a point proximate the midpoint of the assembly 12 (e.g., the feed point 46), as shown in FIG. 7. The inflow tubes 86a and 86b are then secured to the radiating portion 18 (e.g., using epoxy, glue, etc.). The inflow tubes 86a and 86b are positioned in this configuration to provide optimal coolant flow through the sheath 38. The fluid flow from the inflow tube 86a is directed into the tip 48 and reflected in the proximal direction. The fluid flow from the inflow tube 86b provides the coolant fluid 37 along the radiating portion 18. During operation, the pump 34 supplies fluid to the assembly 12 through the inflow tubes 86a and 86b, thereby circulating the coolant fluid 37 through the entire length of the assembly 12 including the connection hub 22. The coolant fluid 37 is then withdrawn from the first branch 74 and the second branch 76 through the outlet fluid port 30.


The above-discussed coolant system provides for circulation of dielectric coolant fluid 37 (e.g., saline, deionized water, etc.) through the entire length of the antenna assembly 12. The dielectric coolant fluid 37 removes the heat generated by the assembly 12. In addition, the dielectric coolant fluid 37 acts as a buffer for the assembly 12 and prevents near field dielectric properties of the assembly 12 from changing due to varying tissue dielectric properties. For example, as microwave energy is applied during ablation, desiccation of the tissue around the radiating portion 18 results in a drop in tissue complex permittivity by a considerable factor (e.g., about 10 times). The dielectric constant (er′) drop increases the wavelength of microwave energy in the tissue, which affects the impedance of un-buffered microwave antenna assemblies, thereby mismatching the antenna assemblies from the system impedance (e.g., impedance of the cable 16 and the generator 14). The increase in wavelength also results in a power dissipation zone which is much longer in length along the assembly 12 than in cross sectional diameter. The decrease in tissue conductivity (er″) also affects the real part of the impedance of the assembly 12. The fluid dielectric buffering according to the present disclosure also moderates the increase in wavelength of the delivered energy and drop in conductivity of the near field, thereby reducing the change in impedance of the assembly 12, allowing for a more consistent antenna-to-system impedance match and spherical power dissipation zone despite tissue behavior.


Referring to FIGS. 9 and 10, the cable connector 79 is coupled to the inner conductor 50 and outer conductor 56. More specifically, the inner conductor 50 and the inner insulator 52 extend outside the outer conductor 56 at the proximal end of the feedline 20 and the cable connector 79 is coupled to the inner and outer conductors 50 and 56. The cable connector 79 may be any type of threaded or snap connector adapted to contact the outer conductor 56 and the inner conductor 50. In one embodiment, the cable connector 79 may be an SMA type connector having an outer conductor 91, an insulator (not explicitly shown), and an inner conductor 92, which may be a hollow pin. The inner conductor 92 of the cable connector 79 fits about the inner conductor 50 and the outer conductor 91 thereof contacts the outer conductor 56, with the insulator spacing the outer and inner conductors 91 and 92 apart. Cable connector 79 may be secured to the inner and outer conductors 50 and 56 using soldering, laser welding and other suitable ways, which provide electromechanical contact therebetween at a junction point 93.


Laser welding allows coupling the cable connector 79 to the feedline 20. However, care must be exercised to avoid damaging the outer conductor 56 by the laser. Soldering avoids this issue, but at higher power levels (e.g., about 90 or more Watts) the soldering connection may begin to reflow due to the excessive heat generated by increased power. Embodiments of the present disclosure also provide for a system and method to alleviate the solder reflow by circulating a dielectric coolant fluid through the entire length of the assembly 12 up to the cable connector 79 such that the junction point 93 of the connector 79 to the inner and outer conductors 50 and 56 is cooled.


The connector 79 includes a threaded portion 94 that couples to the distal end of the cable 16, which may also have a corresponding SMA male connector. The connection hub 22 is inserted onto the distal end of the feedline 20 and is slid toward the distal end thereof. The cable connector 79 is then coupled to the proximal end of the first branch 74 thereby securing the connector hub 22 to the feedline 20 (e.g., gluing the connector hub 22 to the cable connector 79).



FIGS. 11 and 12 illustrate one embodiment wherein the first and second branches 74 and 76 are interconnected via a bypass tube 80. A beveled opening 82 is formed in the wall of the second branch 76 and is angled toward the outlet fluid port 30, as shown in FIG. 11. This configuration provides easier insertion of the bypass tube 80 into the second branch 76 as shown in FIGS. 12A-B and 13. An outlet opening 84 is also formed in the first branch 74, at approximately the proximal end thereof such that the outlet opening 84 is proximate the junction point 93 of the connector 79 and the feedline 20 allowing the coolant fluid 37 to contact the connector 79. The outlet opening 84 may be formed at any angle suitable for providing fluid flow between the first branch 74 and the second branch 76. A first end of the bypass tube 80 is attached to the outlet opening 84 such that the first end of the bypass tube 80 is proximate to the junction point 93. A second end of the bypass tube 80 is thereafter inserted through the second branch 76 and the outlet port 30 and is coupled to a male luer type connector 100, which provides for quick coupling and decoupling to the outflow tube 88, as shown in FIG. 13. The bypass tube 80 may be attached to the openings 82 and 84 using a variety of adhesives and other means suitable for sealing any gaps between the openings 82 and 84 and the bypass tube 80. The bypass tube 80 may be compression fit into the male connector 100 and/or glued thereto. The outlet port 30 is sealed via a glue plug or other means around the bypass tube 80, thereby limiting the coolant fluid 37 to outflow through the bypass tube 80. This configuration allows the coolant fluid to flow from the assembly 12 only through the opening 84.


In conventional designs, vapor pockets form at the junction between the connector 79 and the feedline 20 and prevent the coolant fluid 37 from reaching the connector 79, thereby preventing any cooling to take place. As a result, the connector 79 continues to heat up and solder attaching the coupling the connector 79 melts. The bypass tube 80 provides for unrestricted flow of the coolant fluid from the proximal end of the first branch 74 and the connector 79. The bypass tube 80 provides for flow of the coolant fluid directly from the cable connector 79 to the outlet port 30 without withdrawing fluid through the second branch 76. This configuration removes the fluid from the assembly 12 at a rate sufficient to prevent vaporization of the fluid as it comes in contact with the junction point 93 of the connector 79, thereby preventing formation of vapor pockets. In other words, the bypass tube 80 allows for the coolant fluid to circuit to the connector 79 without restrictions caused by pressure build-up resulting from the heat generated at the junction point 93.


The above-discussed coolant system provides circulation of dielectric coolant fluid 37 (e.g., saline, deionized water, etc.) through the entire length of the antenna assembly 12. In addition, the coolant is also brought in contact with the cable connector 79 allowing use of a conventional solder connection to attach the connector 79 to the feedline 20. The fluid provides cooling and enhances dielectric matching properties of the assembly 12. The coolant fluid 37 supplied to the cable connector 79 prevents solder re-flow, allowing the assembly 12 to operate at higher power levels (e.g., 150 watts). The coolant fluid 37 circulated through the sheath 38 also wicks heat away from the feedline 20, which allows delivery of high power signals to the antenna radiating section.



FIGS. 14 and 15 illustrate another embodiment of the connection hub 22 having a bifurcated outflow path configuration, in which the second branch 76 also acts as an outflow path. The connection hub 22 as shown in FIG. 14 does not include the beveled opening 82 since the bypass tube 80 is coupled to the opening 84 within the first branch 74 and is fed directly into a bifurcated coupler 106. The bifurcated coupler 106 includes a male luer connector 108 at a proximal end thereof and a bifurcated port 110 at a distal end thereof. The bifurcated port 110 includes a first port 112 and a second port 114 which are separated by a member 113 at the distal end of the bifurcated port 110 such that the first and second ports 112 and 114 then meet at a chamber 115. The first port 112 is coupled to the second branch 76 through the connector 100 and the second port 114 is coupled to bypass tube 80. This configuration provides for a dual outflow of the coolant fluid 37, from the second branch 76 and the bypass tube 80 and allows for an increased flow rate through the assembly 12.


The described embodiments of the present disclosure are intended to be illustrative rather than restrictive, and are not intended to represent every embodiment of the present disclosure. Embodiments of the present disclosure may also be implemented in a microwave monopolar antenna or other electrosurgical devices. Various modifications and variations can be made without departing from the spirit or scope of the disclosure as set forth in the following claims both literally and in equivalents recognized in law.

Claims
  • 1. A microwave antenna assembly, comprising: a feedline including an inner conductor, an outer conductor and an inner insulator disposed therebetween;a radiating portion including an antenna; a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion, the chamber adapted to circulate coolant fluid therethrough; anda connection hub including a cable connector coupled to the feedline, an inlet fluid port and an outlet fluid port, the connection hub further including a bypass tube configured to provide for flow of the coolant fluid to the outlet fluid port, wherein the bypass tube is disposed distally of the cable connector.
  • 2. A microwave antenna assembly according to claim 1, wherein the sheath is a polyimide catheter.
  • 3. A microwave antenna assembly according to claim 1, further comprising: a tip having an insertion base, a tapered end and a pointed end, wherein the tip is coupled to a distal end of the antenna.
  • 4. A microwave antenna assembly according to claim 3, wherein the sheath is coupled to the connection hub and the tip.
  • 5. A microwave antenna assembly according to claim 1, furthering comprising: at least one inflow tube coupled to the inlet fluid port and disposed within the chamber for supplying the coolant fluid thereto; andat least one outflow tube coupled to the outlet fluid port and in fluid communication with the chamber for withdrawing the coolant fluid therefrom.
  • 6. A microwave antenna assembly according to claim 1, wherein the connection hub is a three-branch connector having a first branch coupled to the cable connector, a second branch coupled to the outlet port and a third branch coupled to the inlet port.
  • 7. A microwave antenna assembly according to claim 6, wherein the bypass tube is in fluid communication with a proximal end of the first branch and the outlet port.
  • 8. A microwave antenna assembly according to claim 7, wherein the bypass tube is inserted into the second branch through a beveled opening and the outlet port is sealed around the bypass tube.
  • 9. A microwave antenna assembly according to claim 7, wherein the connection hub further includes a bifurcated coupler having a first port and a second port in fluid communication with each other, wherein the second port is coupled to second branch and the first port is coupled to the bypass tube.
  • 10. A microwave antenna assembly, comprising: a feedline including an inner conductor, an outer conductor and an inner insulator disposed therebetween;a radiating portion including a dipole antenna having a proximal portion and a distal portion;a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion, the chamber adapted to circulate coolant fluid therethrough; anda three-branch connection hub including a first branch having a cable connector coupled to the feedline at a junction point, a second branch having an outlet port, a third branch having an inlet port, and a bypass tube external to the three-branch connection hub and in fluid communication with a proximal end of the first branch and the outlet port and in proximity with the junction point to provide for flow of the coolant fluid from the cable connector directly to the outlet fluid port.
  • 11. A microwave antenna assembly according to claim 10, wherein the bypass tube is inserted into the second branch through a beveled opening and the outlet port is sealed around the bypass tube.
  • 12. A microwave antenna assembly according to claim 10, wherein the connection hub further includes a bifurcated coupler having a first port and a second port in fluid communication with each other, wherein the second port is coupled to second branch and the first port is coupled to the bypass tube.
  • 13. A microwave antenna assembly according to claim 10, wherein the sheath is a polyimide catheter.
  • 14. A microwave antenna assembly according to claim 10, further comprising: a tip having an insertion base, a tapered end and a pointed end, wherein the tip is coupled to the distal end of the dipole antenna.
  • 15. A microwave antenna assembly according to claim 14, wherein the sheath is coupled to the connection hub and the tip.
  • 16. A microwave antenna assembly according to claim 10, furthering comprising: at least one inflow tube coupled to the inlet fluid port and disposed within the chamber for supplying the coolant fluid thereto; andat least one outflow tube coupled to the outlet fluid port and in fluid communication with the chamber for withdrawing the coolant fluid therefrom.
  • 17. A microwave antenna assembly, comprising: a feedline including an inner conductor, an outer conductor and an inner insulator disposed therebetween;a radiating portion including an antenna;a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion, the chamber adapted to circulate coolant fluid therethrough; anda connection hub including a cable connector coupled to the feedline, an inlet fluid port and an outlet fluid port, the connection hub further including a bypass tube configured to provide for flow of the coolant fluid proximate the cable connector to the outlet fluid port,wherein the connection hub is a three-branch connector having a first branch coupled to the cable connector, a second branch coupled to the outlet port and a third branch coupled to the inlet port, and wherein the bypass tube is in fluid communication with a proximal end of the first branch and the outlet port, and wherein the bypass tube is inserted into the second branch through a beveled opening and the outlet port is sealed around the bypass tube.
  • 18. A microwave antenna assembly, comprising: a feedline including an inner conductor, an outer conductor and an inner insulator disposed therebetween;a radiating portion including a dipole antenna having a proximal portion and a distal portion;a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion, the chamber adapted to circulate coolant fluid therethrough; anda three-branch connection hub including a first branch having a cable connector coupled to the feedline at a junction point, a second branch having an outlet port, a third branch having an inlet port, and a bypass tube in fluid communication with a proximal end of the first branch and the outlet port and in proximity with the junction point to provide for flow of the coolant fluid from the cable connector directly to the outlet fluid port;wherein the bypass tube is inserted into the second branch through a beveled opening and the outlet port is sealed around the bypass tube.
US Referenced Citations (85)
Number Name Date Kind
3631363 Miller Dec 1971 A
4140130 Storm, III Feb 1979 A
4375220 Matvias Mar 1983 A
4397313 Vaguine Aug 1983 A
4462412 Turner Jul 1984 A
4572190 Azam et al. Feb 1986 A
4658836 Turner Apr 1987 A
4662383 Sogawa et al. May 1987 A
4798215 Turner Jan 1989 A
4823812 Eshel et al. Apr 1989 A
5097844 Turner Mar 1992 A
5234004 Hascoet et al. Aug 1993 A
5344435 Turner et al. Sep 1994 A
5370676 Sozanski et al. Dec 1994 A
5413588 Rudie et al. May 1995 A
5417210 Funda et al. May 1995 A
5417686 Peterson et al. May 1995 A
5464445 Rudie et al. Nov 1995 A
5480417 Hascoet et al. Jan 1996 A
5509929 Hascoet et al. Apr 1996 A
5545137 Rudie et al. Aug 1996 A
5599295 Rosen et al. Feb 1997 A
5628770 Thome et al. May 1997 A
5755754 Rudie et al. May 1998 A
5775338 Hastings Jul 1998 A
5776176 Rudie Jul 1998 A
5800486 Thome et al. Sep 1998 A
5829519 Uthe Nov 1998 A
5843144 Rudie et al. Dec 1998 A
5861021 Thome et al. Jan 1999 A
5904709 Arndt et al. May 1999 A
5916240 Rudie et al. Jun 1999 A
5916241 Rudie et al. Jun 1999 A
5931860 Reid et al. Aug 1999 A
5938692 Rudie Aug 1999 A
5944749 Fenn Aug 1999 A
5951546 Lorentzen Sep 1999 A
6007571 Neilson et al. Dec 1999 A
6031375 Atalar et al. Feb 2000 A
6032078 Rudie Feb 2000 A
6059780 Gough et al. May 2000 A
6097985 Kasevich et al. Aug 2000 A
6134476 Arndt et al. Oct 2000 A
6161049 Rudie et al. Dec 2000 A
6181970 Kasevich Jan 2001 B1
6230060 Mawhinney May 2001 B1
6233490 Kasevich May 2001 B1
6275738 Kasevich et al. Aug 2001 B1
6289249 Arndt et al. Sep 2001 B1
6364876 Erb et al. Apr 2002 B1
6375606 Garibaldi et al. Apr 2002 B1
6440158 Saab Aug 2002 B1
6470217 Fenn et al. Oct 2002 B1
6496737 Rudie et al. Dec 2002 B2
6512956 Arndt et al. Jan 2003 B2
6592579 Arndt et al. Jul 2003 B2
6603994 Wallace et al. Aug 2003 B2
6610054 Edwards et al. Aug 2003 B1
6675050 Arndt et al. Jan 2004 B2
6725080 Melkent et al. Apr 2004 B2
6725095 Fenn et al. Apr 2004 B2
6847848 Sterzer et al. Jan 2005 B2
6849063 Eshel et al. Feb 2005 B1
6866624 Chornenky et al. Mar 2005 B2
6944504 Arndt et al. Sep 2005 B1
7244254 Brace et al. Jul 2007 B2
7271363 Lee et al. Sep 2007 B2
7276061 Schaer et al. Oct 2007 B2
7311703 Turovskiy et al. Dec 2007 B2
7387627 Erb et al. Jun 2008 B2
7439736 Meaney et al. Oct 2008 B2
7467015 Van der Weide Dec 2008 B2
7565207 Turner et al. Jul 2009 B2
20020022836 Goble et al. Feb 2002 A1
20040097805 Verard et al. May 2004 A1
20040133254 Sterzer et al. Jul 2004 A1
20040242992 Hareyama Dec 2004 A1
20050113893 Saab May 2005 A1
20050149010 Turovskiy et al. Jul 2005 A1
20050245920 Vitullo et al. Nov 2005 A1
20060259024 Turovskiy et al. Nov 2006 A1
20070016180 Lee, Jr. et al. Jan 2007 A1
20070016181 Van Der Weide et al. Jan 2007 A1
20070203551 Cronin et al. Aug 2007 A1
20080308256 Deborski et al. Dec 2008 A1
Foreign Referenced Citations (99)
Number Date Country
390937 Mar 1924 DE
1099658 Feb 1961 DE
1139927 Nov 1962 DE
1149832 Jun 1963 DE
1439302 Jan 1969 DE
2439587 Feb 1975 DE
2455174 May 1975 DE
2407559 Aug 1975 DE
2415263 Oct 1975 DE
2429021 Jan 1976 DE
2460481 Jun 1976 DE
2602517 Jul 1976 DE
2504280 Aug 1976 DE
2627679 Jan 1977 DE
2540968 Mar 1977 DE
2820908 Nov 1978 DE
2803275 Aug 1979 DE
2823291 Nov 1979 DE
2946728 May 1981 DE
3143421 May 1982 DE
3045996 Jul 1982 DE
3120102 Dec 1982 DE
3510586 Oct 1986 DE
3604823 Aug 1987 DE
8712328 Mar 1988 DE
3711511 Jun 1988 DE
3904558 Aug 1990 DE
3942998 Jul 1991 DE
4238263 May 1993 DE
4303882 Aug 1994 DE
4339049 May 1995 DE
29616210 Jan 1997 DE
19608716 Apr 1997 DE
19751106 May 1998 DE
19717411 Nov 1998 DE
19751108 May 1999 DE
19801173 Jul 1999 DE
19848540 May 2000 DE
10224154 Dec 2003 DE
10328514 Mar 2005 DE
102004022206 Dec 2005 DE
202005015147 Mar 2006 DE
0 246 350 Nov 1987 EP
0 481 685 Apr 1992 EP
0 521 264 Jan 1993 EP
0 541 930 May 1993 EP
0 556 705 Aug 1993 EP
0 558 429 Sep 1993 EP
0 572 131 Dec 1993 EP
0 836 868 Apr 1998 EP
1 159 926 May 2001 EP
1 278 007 Jan 2003 EP
1 810 627 Jul 2007 EP
179607 Nov 1906 FR
1 275 415 Sep 1960 FR
1 347 865 Nov 1963 FR
2 276 027 Jun 1974 FR
2 235 669 Jan 1975 FR
2 313 708 Dec 1976 FR
2 502 935 Oct 1982 FR
2 517 953 Jun 1983 FR
2 573 301 Nov 1984 FR
2 862 813 May 2005 FR
2 864 439 Jul 2005 FR
2415630 Jan 2006 GB
5-5106 Jan 1993 JP
05-40112 Feb 1993 JP
06343644 Dec 1994 JP
07265328 Oct 1995 JP
08056955 Mar 1996 JP
08252263 Oct 1996 JP
09010223 Jan 1997 JP
11244298 Sep 1999 JP
2000342599 Dec 2000 JP
2000350732 Dec 2000 JP
2001008944 Jan 2001 JP
2001029356 Feb 2001 JP
2001128990 May 2001 JP
166452 Nov 1964 SU
401367 Nov 1974 SU
WO9618349 Jun 1996 WO
WO9741924 Nov 1997 WO
WO9743971 Nov 1997 WO
WO9748449 Dec 1997 WO
WO9748450 Dec 1997 WO
WO9748451 Dec 1997 WO
WO0048672 Aug 2000 WO
WO0051513 Sep 2000 WO
WO0057811 Oct 2000 WO
WO0101847 Jan 2001 WO
WO0174252 Oct 2001 WO
WO0245790 Jun 2002 WO
WO02061880 Aug 2002 WO
WO2004112628 Dec 2004 WO
WO2005011049 Feb 2005 WO
WO2005016119 Feb 2005 WO
WO2007024878 Mar 2007 WO
WO2007076924 Jul 2007 WO
WO2007112081 Oct 2007 WO
Related Publications (1)
Number Date Country
20100053015 A1 Mar 2010 US