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Publication numberUS20040260282 A1
Publication typeApplication
Application numberUS 10/775,747
Publication date23 Dec 2004
Filing date9 Feb 2004
Priority date15 Aug 1995
Also published asUS6689127, US8734439, US20080154259
Publication number10775747, 775747, US 2004/0260282 A1, US 2004/260282 A1, US 20040260282 A1, US 20040260282A1, US 2004260282 A1, US 2004260282A1, US-A1-20040260282, US-A1-2004260282, US2004/0260282A1, US2004/260282A1, US20040260282 A1, US20040260282A1, US2004260282 A1, US2004260282A1
InventorsEdward Gough, Alan Stein
Original AssigneeRita Medical Systems, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Multiple antenna ablation apparatus and method with multiple sensor feedback
US 20040260282 A1
Abstract
An ablation apparatus includes an ablation energy source producing an electromagnetic energy output. A monopolar multiple antenna device is included and has a primary antenna with a longitudinal axis, a central lumen and a distal end, and a secondary antenna with a distal end. The secondary antenna is deployed from the primary antenna central lumen in a lateral direction relative to the longitudinal axis. The primary antenna and secondary antennas are each electromagnetically coupled to the electromagnetic energy source.
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Claims(28)
What is claimed is:
1. An ablation treatment apparatus, comprising:
an introducer having a distal portion and a proximal portion: and at least one antenna positioned in the introducer as the introducer is introduced through tissue and exhibiting a changing direction of travel when deployed from the introducer at a selected tissue mass, said at least one antenna being operatively coupled to a microwave energy source; and
at least one thermal sensor coupled to at least one of (i) the introducer. or (ii) at least one of the at least one antennas.
2. The apparatus of claim 1, wherein at least a portion of a distal end of the at least one antenna is constructed to be structurally less rigid than the introducer, and the introducer is constructed to be rigid enough to be introduced through tissue.
3. The apparatus of claim 1, further comprising:
a feedback control system operatively coupled to the at least one sensor and the microwave energy source.
4-6. (canceled)
7. The apparatus of claim 1, wherein said at least one antenna comprises at least two antennas, each of the antennas having an energy delivery surface to create an ablation volume between the energy delivery surfaces.
8. The apparatus of claim 1, wherein each antenna includes at least one thermal sensor to measure temperature.
9. The apparatus of claim 1, wherein said at least one antenna comprises at least three antennas, each of the antennas having an energy delivery surface to create an ablation volume between the energy delivery surfaces.
10. (canceled)
11. The apparatus of claim 1, further comprising:
an insulation sleeve positioned in a surrounding relationship around at least a portion of at least one of (i) the introducer, or (ii) the at least one antenna.
12. The apparatus of claim 11, wherein the insulation sleeve is adjustably moveable along an exterior of the introducer or the at least one antenna.
13-14. (canceled)
15. The apparatus of claim 1, further including a ground pad electrode.
16-17. (canceled)
18. The apparatus of claim 1, wherein the introducer is hollow and coupled to an infusion medium source to receive an infusion medium.
19. The apparatus of claim 1, further comprising: a cooling element coupled to the introducer.
20. A method for creating an ablation volume in a selected tissue mass, comprising:
providing an ablation device with an introducer at least one antenna with a distal end and being operatively coupled to a microwave energy source, and at least one thermal sensor coupled to at least one of (i) the introducer, or (ii) at least one of the at least one antennas;
inserting the introducer into the selected tissue mass with the at least one antenna distal end positioned in the introducer lumen;
advancing the at least one antenna distal end out of the introducer lumen and into the selected tissue mass;
delivering electromagnetic energy from the microwave energy source to the at least one antenna; and
creating an ablation volume in the selected tissue mass.
21. The method of claim 20, wherein said at least one antenna comprises at least two antennas, each having an energy delivery surface, are advanced from the primary antenna, and an ablation volume is created between the two antennas energy delivery surfaces.
23. The method of claim 21, wherein the at least two antennas are advanced out of a distal end of the introducer
24. The method of claim 21, wherein the at least two antennas are advanced out of separate ports formed in the introducer.
25-29. (canceled)
30. The method of claim 20, wherein the introducer is operatively coupled to an energy source and has an energy delivery surface.
31. The apparatus of claim 3, wherein the feedback control adjusts at least one of (i) a power level, (ii) a duty cycle, and (iii) an energy delivery in response to the temperature measured at the at least one sensor.
32. The apparatus of claim 1, further comprising:
a display for displaying temperature values measured at the at least one sensor.
33. The apparatus of claim 1, wherein said introducer is an antenna operatively coupled to an energy source.
34. The apparatus of claim 33, wherein said introducer is coupled to a RF energy source.
35. The apparatus of claim 1, wherein the introducer includes a tissue piercing distal end.
36. The apparatus of claim 3, further comprising:
a controller coupled to the energy source and at least one of (i) the at least one thermal sensor and (ii) the feedback control to adjust the energy supplied to the antennas in response to the temperature measured at the at least one sensor.
37. The apparatus of claim 20, further comprising:
adjusting the energy supplied to the at least one antenna in response to a temperature measured at the at least one sensor.
Description
    REFERENCE TO RELATED APPLICATION
  • [0001]
    This application is a continuation-in-part of U.S. patent application Ser. No. 08/515,379, filed Aug. 15, 1995, entitled “Multiple Antenna Ablation Apparatus”, incorporated herein by reference.
  • BACKGROUND OF THE INVENTION
  • [0002]
    1. Field of the Invention
  • [0003]
    This invention relates generally to a treatment and ablation apparatus that includes a primary antenna inserted into or adjacent to a selected body mass, such as a tumor, with one or more side deployed secondary antennas which are actively coupled to the primary antenna, and more particularly to a multiple antenna RF treatment and ablation apparatus with one or more secondary antennas actively coupled to the primary antenna, with the primary antenna coupled to a feedback control device and energy source.
  • [0004]
    2. Description of the Related Art
  • [0005]
    Current open procedures for treatment of tumors are extremely disruptive and cause a great deal of damage to healthy tissue. During the surgical procedure, the physician must exercise care in not cutting the tumor in a manner that creates seeding of the tumor, resulting in metastasis. In recent years, development of products has been directed with an emphasis on minimizing the traumatic nature of traditional surgical procedures.
  • [0006]
    There has been a relatively significant amount of activity in the area of hyperthermia as a tool for treatment of tumors. It is known that elevating the temperature of tumors is helpful in the treatment and management of cancerous tissues. The mechanisms of selective treatment are not completely understood. However, four cellular effects of hyperthermia on cancerous tissue have been proposed, (i) changes in cell or nuclear membrane permeability or fluidity, (ii) cytoplasmic lysomal disintegration, causing release of digestive enzymes, (iii) protein thermal damage affecting cell respiration and the synthesis of DNA or RNA and (iv) potential excitation of immunologic systems. Treatment methods for applying heat to tumors include the use of direct contact radio-frequency (RF) applicators, microwave radiation, inductively coupled RF fields, ultrasound, and a variety of simple thermal conduction techniques.
  • [0007]
    Among the problems associated with all of these procedures is the requirement that highly localized heat be produced at depths of several centimeters beneath the surface of the skin. RF applications may be used at depth during surgery. However, the extent of localization is generally poor, with the result that healthy tissue may be harmed.
  • [0008]
    With RF lesion making, a high frequency alternating current flows from the electrode into the tissue. Ionic agitation is produced in the region of tissue about the electrode tip as the ions attempt to follow the directional variations of the alternating current. This agitation results in frictional heating so that the tissue about the electrode, rather than the electrode itself, is the primary source of heat. Tissue heat generated is produced by the flow of current through the electrical resistance offered by the tissue. The greater this resistance, the greater the heat generated.
  • [0009]
    Lesion size ultimately is governed by tissue temperature. Some idea of tissue temperature can be obtained by monitoring the temperature at an electrode or probe tip, usually with a thermistor. RF lesion heat is generated within the tissue, the temperature monitored will be the resultant heating of the electrode by the lesion. RF lesion heat is generated within the tissue, the temperature monitored is the resultant heating of the probe by the lesion. A temperature gradient extends from the lesion to the probe tip, so that the probe tip is slightly cooler than the tissue immediately surrounding it, but substantially hotter than the periphery of the lesion because of the rapid attenuation of heating effect with distance.
  • [0010]
    Current spreads out radially from the electrode tip, so that current density is greatest next to the tip, and decreases progressively at distances from it. The frictional heat produced from ionic agitation is proportional to current, i.e., ionic density. Therefore, the heating effect is greatest next to the electrode and decreases with distance from it. One consequence of this is that lesions can inadvertently be made smaller than anticipated for a given electrode size if the RF current level is too high. There must be time for equilibrium heating of tissue to be reached, especially at the center of the desired lesion volume. If the current density is too high, the tissue temperature next to the electrode rapidly exceeds desired levels and carbonization and boiling occurs in a thin tissue shell surrounding the electrode tip.
  • [0011]
    A need exists for an ablation apparatus with an electromagnetic energy source and a monopolar multiple antenna device. There is a further need for a monopolar multiple antenna device with a primary antenna, and one or more secondary antennas that are positioned in a lumen of the primary antenna, laterally deployable from the primary antenna into a selected tissue mass, with both antennas electromagnetically coupled to an electromagnetic energy source. It would be desirable to provide a monopolar method to ablate a selected tissue mass by introducing the primary antenna into the selected mass, deploying a distal end of the secondary antenna into the selected mass, and applying electromagnetic energy to the primary and secondary antennas.
  • SUMMARY OF THE INVENTION
  • [0012]
    Accordingly, it is an object of the invention to provide an ablation device which includes a monopolar multiple antenna.
  • [0013]
    Another object of the invention is to provide an ablation apparatus with a monopolar multiple antenna device including a primary antenna that pierces and advances through tissue, a secondary electrode positioned in a primary antenna lumen that is laterally deployable from the primary antenna into a selected tissue mass.
  • [0014]
    Yet another object of the invention is to provide an ablation apparatus with a monopolar multiple antenna device, including primary and secondary antennas that are each electromagnetically coupled to an electromagnetic energy source.
  • [0015]
    A further object of the invention is to provide a method for ablating a selected tissue mass utilizing a monopolar multiple antenna device.
  • [0016]
    These and other objectives are achieved in an ablation treatment apparatus. The apparatus includes an ablation energy source producing an electromagnetic energy output. A monopolar multiple antenna device is included and has a primary antenna with a longitudinal axis, a central lumen and a distal end, and a secondary antenna with a distal end. The secondary antenna is deployed from the primary antenna central lumen in a lateral direction relative to the longitudinal axis. The primary antenna and secondary antennas are each electromagnetically coupled to the electromagnetic energy source.
  • [0017]
    In another embodiment, a method of ablating a selected tissue mass is provided utilizing a monopolar multiple antenna device.
  • [0018]
    The monopolar multiple antenna device can be an RF antenna, a microwave antenna, a short wave antenna and the like. At least two secondary antennas can be included and laterally deployed from the primary antenna. The secondary antenna is retractable into the primary antenna, permitting repositioning of the primary antenna. When the multiple antenna is an RF antenna, it can be operated in monopolar or bipolar modes, and is capable of switching between the two.
  • [0019]
    One or more sensors may be positioned at an interior or exterior of the primary or secondary antennas to detect impedance or temperature. A feedback control system is coupled to each of the sensors, the electromagnetic energy source and the primary and secondary antennas.
  • [0020]
    An insulation sleeve can be positioned around the primary and secondary antennas. Another sensor is positioned at the distal end of the insulation sleeve surrounding the primary antenna.
  • [0021]
    The feedback control device can detect impedance or temperature at a sensor. In some embodiments, the feedback control system can include a multiplexer. Further, the feedback control system can provide an ablation energy output for a selected length of time, adjust ablation energy output and reduce or cut off the delivery of the ablation energy output to the antennas. The feedback control system can include a temperature detection circuit which provides a control signal representative of temperature or impedance detected at any of the sensors. The feedback control system can also include a microprocessor connected to the temperature detection circuit. Initially, temperature, ablation duration and energy level are selected and manually input into the feedback control system. As process parameters change, the initial manually input values are then automatically modified by the feedback control system to achieve the desired level of ablation without impeding out, and minimize the ablation of non-targeted tissue.
  • [0022]
    Further, the multiple antenna device can be a multi-modality apparatus. One or all of the antennas can be hollow to receive an infusion medium from an infusion source and introduce the infusion medium into the targeted tissue mass.
  • BRIEF DESCRIPTION OF THE FIGURES
  • [0023]
    [0023]FIG. 1 is a perspective view of the multiple antenna ablation apparatus of the present invention illustrating a primary antenna and a single laterally deployed secondary antenna.
  • [0024]
    [0024]FIG. 2 is a perspective view of a conic geometric ablation achieved with the apparatus of FIG. 1.
  • [0025]
    [0025]FIG. 3 is a perspective view of the multiple antenna ablation apparatus of the present invention with two secondary antennas.
  • [0026]
    [0026]FIG. 4 is a perspective view illustrating the adjacent positioning of the multiple antenna ablation apparatus next to a selected tissue mass.
  • [0027]
    [0027]FIG. 5 is a perspective view illustrating the positioning of the multiple antenna ablation apparatus in the center of a selected tissue mass, and the creation of a cylindrical ablation.
  • [0028]
    [0028]FIG. 6(a) is a perspective view of the multiple antenna ablation of the present invention illustrating two secondary antennas which provide a retaining and gripping function.
  • [0029]
    [0029]FIG. 6(b) is a perspective view of the multiple antenna ablation of the present invention illustrating three secondary antennas which provide a retaining and gripping function.
  • [0030]
    [0030]FIG. 6(c) is a cross-sectional view of the apparatus of FIG. 6(b) taken along the lines 6(c)-6(c).
  • [0031]
    [0031]FIG. 7 is a perspective view of the multiple antenna ablation of the present invention illustrating the deployment of three secondary antennas from a distal end of the insulation sleeve surrounding the primary antenna.
  • [0032]
    [0032]FIG. 8 is a perspective view of the multiple antenna ablation of the present invention illustrating the deployment of two secondary antennas from the primary antenna, and the deployment of three secondary antennas from the distal end of the insulation sleeve surrounding the primary antenna.
  • [0033]
    [0033]FIG. 9 is a block diagram illustrating the inclusion of a controller, energy source and other electronic components of the present invention.
  • [0034]
    [0034]FIG. 10 is a block diagram illustrating an analog amplifier, analog multiplexer and microprocessor used with the present invention.
  • DETAILED DESCRIPTION
  • [0035]
    The present invention provides an ablation treatment apparatus which includes an ablation energy source producing an electromagnetic energy output. A monopolar multiple antenna device is included and has a primary antenna with a longitudinal axis, a central lumen and a distal end, and a secondary antenna with a distal end. The secondary antenna is deployed from the primary antenna central lumen in a lateral direction relative to the longitudinal axis. The primary antenna and secondary antennas are each electromagnetically coupled to the electromagnetic energy source.
  • [0036]
    As shown in FIG. 1, an ablation treatment apparatus 10 includes a monopolar multiple antenna device 12. Monopolar multiple antenna device 12 includes a primary antenna 14, and one or more secondary antennas 16, which are typically electrodes. Secondary antennas 16 are initially positioned in a primary antenna lumen when primary antenna 14 is advanced through tissue. When primary antenna 14 reaches a selected tissue ablation site in a selected tissue mass, including but not limited to a solid lesion, secondary antennas 16 are laterally deployed from the primary antenna lumen and into the selected tissue mass. Ablation proceeds from the interior of the selected tissue mass in a direction towards a periphery of the selected tissue mass.
  • [0037]
    Each primary and secondary antenna 14 and 16 has an exterior ablation surface which delivers electromagnetic energy to the selected tissue mass. The length and size of each ablation surface can be variable. The length of primary antenna ablation surface relative to secondary antenna ablation surface can be 20% or greater, 33 and ⅓% or greater, 50% or greater, 75% or greater, about the same length, or greater than the length of secondary electrode ablation surface. Lengths of primary and secondary antennas 14 and 16 can be adjustable. Primary antenna 14 can be moved up and down, rotated about its longitudinal axis, and moved back and forth, in order to define, along with sensors, the periphery or boundary of the selected tissue mass, including but not limited to a tumor. This provides a variety of different geometries, not always symmetrical, that can be ablated. The ablation can be between the ablation surfaces of primary and secondary antennas 14 and 16 when operated in a mono-polar mode with a ground pad.
  • [0038]
    Primary antenna 14 is constructed so that it can be introduced percutaneously or laparoscopically through tissue without an introducer. Primary antenna 14 combines the function of an introducer and an electrode.
  • [0039]
    In one embodiment, primary antenna 14 can have a. sharpened distal end 14′ to assist introduction through tissue. Each secondary antenna 16 has a distal end 16′ that is constructed to be less structurally rigid than primary antenna 14. Distal end 16′ is that section of secondary antenna 16 that. is advanced from the lumen antenna 14 and into the selected tissue mass. Distal end is typically less structurally rigid that primary antenna 14. However, even though sections of secondary antenna 16 which are not advanced through the selected tissue mass may be less structurally rigid than primary antenna 14.
  • [0040]
    Structurally rigidity is determined by, (i) choosing different materials for antenna 14 and distal end 16′ or some greater length of secondary antenna 16, (ii) using the same material but having less of it for secondary antenna 16 or distal end 16′, e.g., secondary antenna 16 or distal end 16′ is not as thick as primary electrode 14, or (iii) including another material in one of the antennas 14 or 16 to vary their structural rigidity. For purposes of this disclosure, structural rigidity is defined as the amount of deflection that an antenna has relative to its longitudinal axis. It will be appreciated that a given antenna will have different levels of rigidity depending on its length.
  • [0041]
    Primary and secondary antennas 14 and 16 can be made of a variety of conductive materials, both metallic and non-metallic. One suitable material is type 304 stainless steel of hypodermic quality. In some applications, all or a portion of secondary electrode 16 can be made of a shaped memory metal, such as NiTi, commercially available from Raychem Corporation, Menlo Park, Calif.
  • [0042]
    Each of primary or secondary antennas 14 or 16 can have different lengths. The lengths can be determined by the actual physical length of an antenna, the amount of an antenna that has an ablation delivery surface, and the length of an antenna that is not covered by an insulator. Suitable lengths include but are not limited to 17.5 cm, 25.0 cm. and 30.0 cm. The actual length of an antenna depends on the location of the selected tissue mass to be ablated, its distance from the skin, its accessibility as well as whether or not the physician chooses a laproscopic, percutaneous or other procedure. Further, ablation treatment apparatus 10, and more particularly multiple antenna device 12, can be introduced through a guide to the desired tissue mass site.
  • [0043]
    An insulation sleeve 18 may be positioned around an exterior of one or both of the primary and secondary antennas 14 and 16 respectively. Preferably, each insulation sleeve 18 is adjustably positioned so that the length of an antenna ablation surface can be varied. Each insulation sleeve 18 surrounding a primary antenna 14 can include one or more apertures. This permits the introduction of a secondary antenna 16 through primary antenna 14 and insulation sleeve 18.
  • [0044]
    In one embodiment, insulation sleeve 18 can comprise a polyamide material. A sensor 24 may be positioned on top of polyimide insulation sleeve 18. The polyamide insulation sleeve 18 is semi-rigid. Sensor 24 can lay down substantially along the entire length of polyamide insulation sleeve 18. Primary antenna 14 is made of a stainless-steel hypodermic tubing with 2 cm of exposed ablation surface. Secondary antennas 16 have distal ends 16′ that are made of
  • [0045]
    NiTi hypodermic tubing. A handle is included with markings to show the varying distance of secondary antennas 16 from primary antenna 14. Fluid infusion is delivered through a Luer port at a side of the handle. Type-T thermocouples are positioned at distal ends 16′.
  • [0046]
    An energy source 20 is connected to multiple antenna device 12 with one or more cables 22. Energy source 20 can be an RF source, microwave source, short wave source, laser source and the like. Multiple antenna device 12 can be comprised of primary and secondary antennas 14 and 16 that are RF electrodes, microwave antennas, as well as combinations thereof. Energy source 20 may be a combination RF/microwave box. Further a laser optical fiber, coupled to a laser source 20 can be introduced through one or both of primary or secondary antennas 14 and 16. One or more of the primary or secondary antennas 14 and 16 can be an arm for the purposes of introducing the optical fiber.
  • [0047]
    Antennas 14 and 16 are each electromagnetically coupled to energy source 20. The coupling can be direct from energy source 20 to each antenna 14 and 16, or indirect by using a collet, sleeve and the like which couples antennas 14 and 16 to energy source 20.
  • [0048]
    One or more sensors 24 may be positioned on at least a portion of interior or exterior surfaces of primary antenna 14, secondary antenna 16 or insulation sleeve 18. Preferably sensors 24 are positioned at primary antenna distal end 14′, secondary antenna distal end 16′ and insulation sleeve distal end 18′. Sensors 24 permit accurate measurement of temperature at a tissue site in order to determine, (i) the extent of ablation, (ii) the amount of ablation, (iii) 25 whether or not further ablation is needed and (iv) the boundary or periphery of the ablated mass. Further, sensors 24 prevent non-targeted tissue from being destroyed or ablated.
  • [0049]
    Sensors 24 are of conventional design, including but not limited to thermistors, thermocouples, resistive wires, and the like. Suitable thermal sensors 24 include a T type thermocouple with copper constantene, J type, E type, K type, fiber optics, resistive wires, thermocouple IR detectors, and the like. It will be appreciated that sensors 24 need not be thermal sensors.
  • [0050]
    Sensors 24 measure temperature and/or impedance to permit monitoring and a desired level of ablation to be achieved without destroying too much tissue. This reduces damage to tissue surrounding the targeted mass to be ablated. By monitoring the temperature at various points within the interior of the selected tissue mass, a determination of the selected tissue mass periphery can be made, as well as a determination of when ablation is complete. If at any time sensor 24 determines that a desired ablation temperature is exceeded, then an appropriate feedback signal is received at energy source 20 which then regulates the amount of energy delivered to primary and/or secondary antennas 14 and 16.
  • [0051]
    Thus the geometry of the ablated mass is selectable and controllable. Any number of different ablation geometries can be achieved. This is a result of having variable lengths for primary antenna 14 and secondary antenna 16 ablation surfaces as well as the inclusion of sensors. 24.
  • [0052]
    Preferably, distal end 16′ is laterally deployed relative to a longitudinal axis of primary antenna 14 out of an aperture 26 formed in primary antenna 14. Aperture 26 is at distal end 14′ or formed in a side of an exterior of antenna 14.
  • [0053]
    In one embodiment, a method for creating an ablation volume in a selected tissue mass includes; providing a monopolar ablation device with a primary antenna, a secondary antenna with a distal end, and an energy source electromagnetically coupled to both antennas. A ground pad electrode is also included. The primary antenna is inserted into the selected tissue mass with the secondary antenna distal end positioned in the primary antenna lumen. The secondary antenna distal end is advanced out of the primary antenna lumen into the selected tissue mass in a lateral direction relative to a longitudinal axis of the primary antenna. Electromagnetic energy is delivered from one of a primary antenna ablation surface, a secondary antenna ablation surface or both to the selected tissue mass. This creates an ablation volume in the selected tissue mass.
  • [0054]
    There is wide variation in the amount of deflection of secondary antenna 16. For example, secondary antenna 16 can be deflected a few degrees from the longitudinal axis of primary antenna 14, or secondary antenna can be deflected in any number of geometric configurations, including but not limited to a “J” hook. Further, secondary antenna 16 is capable of being introduced from primary antenna 14 a few millimeters from primary antenna, or a much larger distance. Ablation by secondary antenna 16 can begin a few millimeters away from primary antenna 14, or secondary electrode 16 can be advanced a greater distance from primary antenna 14 and at that point the initial ablation by secondary antenna 16 begins.
  • [0055]
    A number of parameters permit ablation of selected tissue masses, including but not limited to tumors, of different size and shapes including, a series of ablations having primary and secondary antennas 14 and 16 with variable length ablation surfaces, the use of sensors 24 and the use of the feedback control system.
  • [0056]
    As illustrated in FIG. 2, primary antenna 14 has been introduced into a selected tissue mass 28. One or more secondary antennas are positioned within a primary antenna lumen as primary antenna 14 is introduced into and through the selected tissue mass. Subsequently, secondary antenna distal end 16′ is advanced out of aperture 26 and into selected tissue mass 28. Insulation sleeves 18 are adjusted for primary and secondary antennas 14 and 16 respectively. RF, microwave, short wave and the like energy is delivery to antenna 16 in a monopolar mode (RF), or alternatively, multiple antenna device 12 can be operated in a bipolar mode (RF). Multi antenna device 12 can be switched between monopolar and bipolar operation and has multiplexing capability between antennas 14 and 16. Secondary antenna distal end 16′ is retracted back into primary antenna 14, and primary antenna is then rotated. Secondary antenna distal end 16′ is then introduced into selected tissue mass 28. Secondary antenna may be introduced a short distance into selected tissue mass 28 to ablate a small area. It can then be advanced further into any number of times to create more ablation zones. Again, secondary antenna distal end 16′ is retracted back into primary antenna 14, and primary antenna 14 can be, (i) rotated again, (ii) moved along a longitudinal axis of selected tissue mass 28 to begin another series of ablations with secondary antenna distal end 16′ being introduced and retracted in and out of primary antenna 14, or (iii) removed from selected tissue mass 28. A number of parameters permit ablation of selected tissue masses 28 of different sign and shapes including a series of ablations having primary and secondary antennas 14 and 16 with variable length ablation surfaces and the use of sensor 24.
  • [0057]
    In FIG. 3, two secondary antennas 16 are each deployed out of distal end 14′ and introduced into selected tissue mass 28. Secondary antennas 16 form a plane and the area of ablation extends between the ablation surfaces of primary and secondary antennas 14 and 16. Primary antenna 14 can be introduced in an adjacent relationship to selected tissue mass 28. This particular deployment is particularly useful for small selected tissue masses 28, or where piercing selected tissue mass 28 is not desirable. Primary antenna 14 can be rotated, with secondary antennas 16 retracted into a central lumen of primary antenna 14, and another ablation volume defined between the two secondary antennas 16 is created. Further, primary electrode 14 can be withdrawn from its initial position adjacent to selected tissue mass 28, repositioned to another position adjacent to selected tissue mass 28, and secondary antennas 16 deployed to begin another ablation cycle. Any variety of different positionings may be utilized to create a desired ablation geometry for selected tissue mass of different geometries and sizes.
  • [0058]
    In FIG. 4, three secondary antennas 16 are introduced into selected tissue mass 28. The effect is the creation of an ablation volume without leaving non-ablated areas between antenna ablation surfaces. The ablation is complete.
  • [0059]
    Referring now to FIG. 5, a center of selected tissue mass 28 is pierced by primary antenna 14, secondary antennas 16 are laterally deployed and retracted, primary antenna 14 is rotated, secondary antennas 16 are deployed and retracted, and so on until a cylindrical ablation volume is achieved. Multiple antenna device 12 can be operated in the bipolar mode between the two secondary antennas 16, or between a secondary antenna 16 and primary antenna 14. Alternatively, multiple antenna device 12 can be operated in a monopolar mode.
  • [0060]
    Secondary antennas 16 can serve the additional function of anchoring multiple antenna device 12 in a selected mass, as illustrated in FIGS. 6(a) and 6(b). In FIG. 6(a) one or both secondary antennas 16 are used to anchor and position primary antenna 14. Further, one or both secondary antennas 16 are also used to ablate tissue. In FIG. 6(b), three secondary antennas are deployed and anchor primary antenna 14.
  • [0061]
    [0061]FIG. 6(c) illustrates the infusion capability of multiple antenna device 12. Three secondary antennas 16 are positioned in a central lumen 14″ of primary antenna 14. One or more of the secondary antennas 16 can also include a central lumen coupled to an infusion source. Central lumen 14″ is coupled to an infusion source and delivers a variety of infusion mediums to selected places both within and outside of the targeted ablation mass. Suitable infusion mediums include but are not limited to, therapeutic agents, conductivity enhancement mediums, contrast agents or dyes, and the like. An example of a therapeutic agent is a chemotherapeutic agent.
  • [0062]
    As shown in FIG. 7 insulation sleeve 18 can include one or more lumens for receiving secondary antennas 16 which are deployed out of an insulation sleeve distal end 18′. FIG. 8 illustrates two secondary antennas 16
  • [0063]
    being introduced out of insulation sleeve distal end 18′, and two secondary antennas 16 introduced through apertures 26 formed in primary antenna 14. As illustrated, the secondary electrodes introduced through apertures 26 provide an anchoring function. It will be appreciated that FIG. 8 illustrates how secondary antennas 16 can have a variety of different geometric configurations in multiple antenna device 12.
  • [0064]
    A feedback control system 29 is connected to energy source 20, sensors 24 and antennas 14 and 16. Feedback control system 29 receives temperature or impedance data from sensors 24 and the amount of electromagnetic energy received by antennas 14 and 16 is modified from an initial setting of ablation energy output, ablation time, temperature, and current density (the “Four Parameters”). Feedback control system 29 can automatically change any of the Four Parameters. Feedback control system 29 can detect impedance or temperature and change any of the Four Parameters. Feedback control system can include a multiplexer to multiplex different antennas, a temperature detection circuit that provides a control signal representative of temperature or impedance detected at one or more sensors 24. A microprocessor can be connected to the temperature control circuit.
  • [0065]
    The following discussion pertains particularly to the use of an RF energy source and RF multiple antenna device 12. It will be appreciated that devices similar to those associated with RF multiple antenna device 12 can be utilized with laser optical fibers, microwave devices and the like.
  • [0066]
    Referring now to FIG. 9, all or portions of feedback control system 29 are illustrated. Current delivered through primary and secondary antennas 14 and 16 is measured by current sensor 30. Voltage is measured by voltage sensor 32. Impedance and power are then calculated at power and impedance calculation device 34. These values can then be displayed at user interface and display 36. Signals representative of power and impedance values are received by controller 38. A control signal is generated by controller 38 that is proportional to the difference between an actual measured value, and a desired value. The control signal is used by power circuits 40 to adjust the power output in an appropriate amount in order to maintain the desired power delivered at the respective primary and/or secondary antennas 14 and 16.
  • [0067]
    In a similar manner, temperatures detected at sensors 24 provide feedback for maintaining a selected power. The actual temperatures are measured at temperature measurement device 42, and the temperatures are displayed at user interface and display 36. A control signal is generated by controller 38 that is proportional to the difference between an actual measured temperature, and a desired temperature. The control signal is used by power circuits 40 to adjust the power output in an appropriate amount in order to maintain the desired temperature delivered at the respective sensor 24. A multiplexer can be included to measure current, voltage and temperature, at the numerous sensors 24, and energy is delivered between primary antenna 14 and secondary antennas 16.
  • [0068]
    Controller 38 can be a digital or analog controller, or a computer with software. When controller 3 8 is a computer it can include a CPU coupled through a system bus. On this system can be a keyboard, a disk drive, or other non-volatile memory systems, a display, and other peripherals, as are known in the art. Also coupled to the bus are a program memory and a data memory.
  • [0069]
    User interface and display 36 includes operator controls and a display. Controller 38 can be coupled to imaging systems, including but not limited to ultrasound, CT scanners, X-ray, MRI, mammographic X-ray and the like. Further, direct visualization and tactile imaging can be utilized.
  • [0070]
    The output of current sensor 30 and voltage sensor 32 is used by controller 38 to maintain a selected power level at primary and secondary antennas 14 and 16. The amount of RF energy delivered controls the amount of power. A profile of power delivered can be incorporated in controller 38, and a preset amount of energy to be delivered can also be profiled.
  • [0071]
    Circuitry, software and feedback to controller 38 result in process control, and the maintenance of the selected power, and are used to change, (i) the selected power, including RF, microwave, laser and the like, (ii) the duty cycle (on-off and wattage), (iii) bipolar or monopolar energy delivery and (iv) infusion medium delivery, including flow rate and pressure. These process variables are controlled and varied, while maintaining the desired delivery of power independent of changes in voltage or current, based on temperatures monitored at sensors 24.
  • [0072]
    Referring now to FIG. 10, current sensor 30 and voltage sensor 32 are connected to the input of an analog amplifier 44. Analog amplifier 44 can be a conventional differential amplifier circuit for use with sensors 24. The output of analog amplifier 44 is sequentially connected by an analog multiplexer 46 to the input of A/D converter 48. The output of analog amplifier 44 is a voltage which represents the respective sensed temperatures. Digitized amplifier output voltages are supplied by A/D converter 48 to a microprocessor 50. Microprocessor 50 may be Model No. 68HCII available from Motorola. However, it will be appreciated that any suitable microprocessor or general purpose digital or analog computer can be used to calculate impedance or temperature.
  • [0073]
    Microprocessor 50 sequentially receives and stores digital representations of impedance and temperature. Each digital value received by microprocessor 50 corresponds to different temperatures and impedances.
  • [0074]
    Calculated power and impedance values can be indicated on user interface and display 36. Alternatively, or in addition to the numerical indication of power or impedance, calculated impedance and power values can be compared by microprocessor 50 with power and impedance limits. When the values exceed predetermined power or impedance values, a warning can be given on user interface and display 36, and additionally, the delivery of RF energy can be reduced, modified or interrupted. A control signal from microprocessor 50 can modify the power level supplied by energy source 20.
  • [0075]
    The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4016886 *26 Nov 197412 Apr 1977The United States Of America As Represented By The United States Energy Research And Development AdministrationMethod for localizing heating in tumor tissue
US4043342 *26 Feb 197623 Aug 1977Valleylab, Inc.Electrosurgical devices having sesquipolar electrode structures incorporated therein
US4074718 *17 Mar 197621 Feb 1978Valleylab, Inc.Electrosurgical instrument
US4080959 *18 Jun 197628 Mar 1978Leveen Robert FMethod for detection of tumors of the breast
US4095602 *27 Sep 197620 Jun 1978Leveen Harry HMulti-portal radiofrequency generator
US4140130 *31 May 197720 Feb 1979Storm Iii Frederick KElectrode structure for radio frequency localized heating of tumor bearing tissue
US4154246 *25 Jul 197715 May 1979Leveen Harry HField intensification in radio frequency thermotherapy
US4285346 *14 Mar 197925 Aug 1981Harry V. LeVeenElectrode system
US4290435 *7 Sep 197922 Sep 1981Thermatime A.G.Internally cooled electrode for hyperthermal treatment and method of use
US4346715 *13 May 198031 Aug 1982The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationHyperthermia heating apparatus
US4375220 *9 May 19801 Mar 1983Matvias Fredrick MMicrowave applicator with cooling mechanism for intracavitary treatment of cancer
US4565200 *4 May 198221 Jan 1986Cosman Eric RUniversal lesion and recording electrode system
US4574782 *21 Nov 198311 Mar 1986Corning Glass WorksRadio frequency-induced hyperthermia for tumor therapy
US4586490 *27 Feb 19846 May 1986Katz Harry RNeedle inserting instrument means for interstitial radiotherapy
US4601296 *7 Oct 198322 Jul 1986Yeda Research And Development Co., Ltd.Hyperthermia apparatus
US4676258 *5 Jun 198630 Jun 1987Kureha Kagaku Kogyo Kabushiki KaishaDevice for hyperthermia
US4763671 *25 Apr 198616 Aug 1988Stanford UniversityMethod of treating tumors using selective application of heat and radiation
US4800899 *29 Oct 198631 Jan 1989Microthermia Technology, Inc.Apparatus for destroying cells in tumors and the like
US4813429 *5 May 198721 Mar 1989Biodan Medical Systems Ltd.Catheter and probe
US4823791 *8 May 198725 Apr 1989Circon Acmi Division Of Circon CorporationElectrosurgical probe apparatus
US4860744 *2 Nov 198729 Aug 1989Raj K. AnandThermoelectrically controlled heat medical catheter
US4920978 *31 Aug 19881 May 1990Triangle Research And Development CorporationMethod and apparatus for the endoscopic treatment of deep tumors using RF hyperthermia
US4931047 *30 Sep 19875 Jun 1990Cavitron, Inc.Method and apparatus for providing enhanced tissue fragmentation and/or hemostasis
US4945912 *25 Nov 19887 Aug 1990Sensor Electronics, Inc.Catheter with radiofrequency heating applicator
US4947842 *13 Feb 198914 Aug 1990Medical Engineering And Development Institute, Inc.Method and apparatus for treating tissue with first and second modalities
US4983159 *17 Sep 19868 Jan 1991Rand Robert WInductive heating process for use in causing necrosis of neoplasms at selective frequencies
US5003991 *24 Mar 19882 Apr 1991Olympus Optical Co., Ltd.Hyperthermia apparatus
US5007908 *29 Sep 198916 Apr 1991Everest Medical CorporationElectrosurgical instrument having needle cutting electrode and spot-coag electrode
US5009656 *17 Aug 198923 Apr 1991Mentor O&O Inc.Bipolar electrosurgical instrument
US5010897 *26 Apr 198930 Apr 1991Leveen Harry HApparatus for deep heating of cancer
US5047027 *20 Apr 199010 Sep 1991Everest Medical CorporationTumor resector
US5078717 *10 Sep 19907 Jan 1992Everest Medical CorporationAblation catheter with selectively deployable electrodes
US5085659 *21 Nov 19904 Feb 1992Everest Medical CorporationBiopsy device with bipolar coagulation capability
US5099756 *1 Jun 198931 Mar 1992Harry H. LeveenRadio frequency thermotherapy
US5100423 *21 Aug 199031 Mar 1992Medical Engineering & Development Institute, Inc.Ablation catheter
US5122137 *27 Apr 199016 Jun 1992Boston Scientific CorporationTemperature controlled rf coagulation
US5125928 *19 Feb 199130 Jun 1992Everest Medical CorporationAblation catheter with selectively deployable electrodes
US5190517 *6 Jun 19912 Mar 1993Valleylab Inc.Electrosurgical and ultrasonic surgical system
US5190541 *17 Oct 19902 Mar 1993Boston Scientific CorporationSurgical instrument and method
US5197466 *7 Jan 199230 Mar 1993Med Institute Inc.Method and apparatus for volumetric interstitial conductive hyperthermia
US5197963 *2 Dec 199130 Mar 1993Everest Medical CorporationElectrosurgical instrument with extendable sheath for irrigation and aspiration
US5197964 *12 Nov 199130 Mar 1993Everest Medical CorporationBipolar instrument utilizing one stationary electrode and one movable electrode
US5203782 *26 Mar 199120 Apr 1993Gudov Vasily FMethod and apparatus for treating malignant tumors by local hyperpyrexia
US5217458 *9 Apr 19928 Jun 1993Everest Medical CorporationBipolar biopsy device utilizing a rotatable, single-hinged moving element
US5236410 *11 Mar 199117 Aug 1993Ferrotherm International, Inc.Tumor treatment method
US5246438 *9 Jan 199221 Sep 1993Sensor Electronics, Inc.Method of radiofrequency ablation
US5275162 *25 Nov 19924 Jan 1994Ep Technologies, Inc.Valve mapping catheter
US5277696 *13 Oct 199211 Jan 1994Delma Elektro- Und Medizinische Apparatebau Gesellschaft MbhMedical high frequency coagulation instrument
US5281217 *13 Apr 199225 Jan 1994Ep Technologies, Inc.Steerable antenna systems for cardiac ablation that minimize tissue damage and blood coagulation due to conductive heating patterns
US5281218 *5 Jun 199225 Jan 1994Cardiac Pathways CorporationCatheter having needle electrode for radiofrequency ablation
US5282797 *28 May 19911 Feb 1994Cyrus ChessMethod for treating cutaneous vascular lesions
US5290286 *9 Dec 19921 Mar 1994Everest Medical CorporationBipolar instrument utilizing one stationary electrode and one movable electrode
US5293869 *25 Sep 199215 Mar 1994Ep Technologies, Inc.Cardiac probe with dynamic support for maintaining constant surface contact during heart systole and diastole
US5295955 *14 Feb 199222 Mar 1994Amt, Inc.Method and apparatus for microwave aided liposuction
US5309910 *25 Sep 199210 May 1994Ep Technologies, Inc.Cardiac mapping and ablation systems
US5313943 *25 Sep 199224 May 1994Ep Technologies, Inc.Catheters and methods for performing cardiac diagnosis and treatment
US5314466 *13 Apr 199224 May 1994Ep Technologies, Inc.Articulated unidirectional microwave antenna systems for cardiac ablation
US5328467 *8 Nov 199112 Jul 1994Ep Technologies, Inc.Catheter having a torque transmitting sleeve
US5334193 *13 Nov 19922 Aug 1994American Cardiac Ablation Co., Inc.Fluid cooled ablation catheter
US5342357 *13 Nov 199230 Aug 1994American Cardiac Ablation Co., Inc.Fluid cooled electrosurgical cauterization system
US5348554 *1 Dec 199220 Sep 1994Cardiac Pathways CorporationCatheter for RF ablation with cooled electrode
US5383917 *5 Jul 199124 Jan 1995Jawahar M. DesaiDevice and method for multi-phase radio-frequency ablation
US5385544 *14 May 199331 Jan 1995Vidamed, Inc.BPH ablation method and apparatus
US5398683 *16 Jul 199321 Mar 1995Ep Technologies, Inc.Combination monophasic action potential/ablation catheter and high-performance filter system
US5403311 *29 Mar 19934 Apr 1995Boston Scientific CorporationElectro-coagulation and ablation and other electrotherapeutic treatments of body tissue
US5409453 *19 Aug 199325 Apr 1995Vidamed, Inc.Steerable medical probe with stylets
US5417687 *30 Apr 199323 May 1995Medical Scientific, Inc.Bipolar electrosurgical trocar
US5421819 *13 May 19936 Jun 1995Vidamed, Inc.Medical probe device
US5423807 *24 Jan 199413 Jun 1995Implemed, Inc.Cryogenic mapping and ablation catheter
US5423808 *29 Nov 199313 Jun 1995Ep Technologies, Inc.Systems and methods for radiofrequency ablation with phase sensitive power detection
US5423811 *16 Mar 199413 Jun 1995Cardiac Pathways CorporationMethod for RF ablation using cooled electrode
US5431649 *27 Aug 199311 Jul 1995Medtronic, Inc.Method and apparatus for R-F ablation
US5433708 *7 Jun 199318 Jul 1995Innerdyne, Inc.Method and device for thermal ablation having improved heat transfer
US5435805 *13 May 199325 Jul 1995Vidamed, Inc.Medical probe device with optical viewing capability
US5437662 *17 Feb 19941 Aug 1995American Cardiac Ablation Co., Inc.Fluid cooled electrosurgical cauterization system
US5484400 *23 Mar 199416 Jan 1996Vidamed, Inc.Dual channel RF delivery system
US5486161 *8 Nov 199323 Jan 1996Zomed InternationalMedical probe device and method
US5505730 *24 Jun 19949 Apr 1996Stuart D. EdwardsThin layer ablation apparatus
US5507743 *16 Aug 199416 Apr 1996Zomed InternationalCoiled RF electrode treatment apparatus
US5509419 *16 Dec 199323 Apr 1996Ep Technologies, Inc.Cardiac mapping and ablation systems
US5514130 *11 Oct 19947 May 1996Dorsal Med InternationalRF apparatus for controlled depth ablation of soft tissue
US5514131 *23 Sep 19947 May 1996Stuart D. EdwardsMethod for the ablation treatment of the uvula
US5531676 *27 Sep 19942 Jul 1996Vidamed, Inc.Medical probe device and method
US5531677 *11 Apr 19952 Jul 1996Vidamed, Inc.Steerable medical probe with stylets
US5536240 *27 Sep 199416 Jul 1996Vidamed, Inc.Medical probe device and method
US5536267 *12 Aug 199416 Jul 1996Zomed InternationalMultiple electrode ablation apparatus
US5540655 *5 Jan 199530 Jul 1996Vidamed, Inc.PBH ablation method and apparatus
US5542915 *12 Jan 19946 Aug 1996Vidamed, Inc.Thermal mapping catheter with ultrasound probe
US5542916 *28 Sep 19946 Aug 1996Vidamed, Inc.Dual-channel RF power delivery system
US5542928 *27 Jun 19946 Aug 1996Innerdyne, Inc.Method and device for thermal ablation having improved heat transfer
US5545161 *7 Oct 199413 Aug 1996Cardiac Pathways CorporationCatheter for RF ablation having cooled electrode with electrically insulated sleeve
US5545171 *22 Sep 199413 Aug 1996Vidamed, Inc.Anastomosis catheter
US5545193 *22 Aug 199513 Aug 1996Ep Technologies, Inc.Helically wound radio-frequency emitting electrodes for creating lesions in body tissue
US5546267 *8 Dec 199413 Aug 1996Illinois Tool Works Inc.Communication circuit protector
US5549108 *1 Jun 199427 Aug 1996Ep Technologies, Inc.Cardiac mapping and ablation systems
US5549644 *2 Feb 199427 Aug 1996Vidamed, Inc.Transurethral needle ablation device with cystoscope and method for treatment of the prostate
US5855576 *12 Dec 19965 Jan 1999Board Of Regents Of University Of NebraskaMethod for volumetric tissue ablation
US5868740 *24 Mar 19959 Feb 1999Board Of Regents-Univ Of NebraskaMethod for volumetric tissue ablation
USRE32066 *30 Jun 198221 Jan 1986 Method for treating benign and malignant tumors utilizing radio frequency, electromagnetic radiation
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US944586112 Apr 201220 Sep 2016Thermedical, Inc.Methods and devices for controlling ablation therapy
US961039615 Mar 20134 Apr 2017Thermedical, Inc.Systems and methods for visualizing fluid enhanced ablation therapy
US973074810 Mar 201415 Aug 2017Thermedical, Inc.Devices and methods for shaping therapy in fluid enhanced ablation
US974398411 Aug 201629 Aug 2017Thermedical, Inc.Devices and methods for delivering fluid to tissue during ablation therapy
US20110213356 *5 Nov 20101 Sep 2011Wright Robert EMethods and systems for spinal radio frequency neurotomy
US20110288540 *4 May 201124 Nov 2011Nimbus Concepts, LlcSystems and methods for tissue ablation
US20120277737 *12 Apr 20121 Nov 2012Thermedical, Inc.Devices and methods for remote temperature monitoring in fluid enhanced ablation therapy
US20150141977 *14 May 201321 May 2015National University Corporation Shiga University Of Medical ScienceOrgan Resection Tool
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