U.S. patent application number 11/034503 was filed with the patent office on 2005-09-15 for infusion array ablation apparatus.
This patent application is currently assigned to RITA Medical Systems, Inc.. Invention is credited to Baker, James, Edwards, Stuart D., Lax, Ronald G., Sharkey, Hugh.
Application Number | 20050203503 11/034503 |
Document ID | / |
Family ID | 46279618 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050203503 |
Kind Code |
A1 |
Edwards, Stuart D. ; et
al. |
September 15, 2005 |
Infusion array ablation apparatus
Abstract
An infusion array ablation apparatus includes an elongated
delivery device having a lumen and an infusion array positionable
in the lumen. The infusion array includes an RF electrode and at
least a first and a second infusion member. Each infusion member
has a tissue piercing distal portion and an infusion lumen. At
least one of the first or second infusion members is positionable
in the elongated delivery device in a compacted state and
deployable from the elongated delivery device with curvature in a
deployed state. Also, at least one of the first or second infusion
members exhibits a changing direction of travel when advanced from
the elongated delivery device to a selected tissue site. At least
one infusion port is coupled to one of the elongated delivery
device, the infusion array, the first infusion member or the second
infusion member.
Inventors: |
Edwards, Stuart D.; (Los
Altos, CA) ; Baker, James; (Palo Alto, CA) ;
Sharkey, Hugh; (Redwood Shores, CA) ; Lax, Ronald
G.; (Grass Valley, CA) |
Correspondence
Address: |
PERKINS COIE LLP
P.O. BOX 2168
MENLO PARK
CA
94026
US
|
Assignee: |
RITA Medical Systems, Inc.
|
Family ID: |
46279618 |
Appl. No.: |
11/034503 |
Filed: |
January 12, 2005 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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11034503 |
Jan 12, 2005 |
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10700605 |
Nov 3, 2003 |
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10700605 |
Nov 3, 2003 |
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09513725 |
Feb 24, 2000 |
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6641580 |
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09513725 |
Feb 24, 2000 |
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09383166 |
Aug 25, 1999 |
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6471698 |
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09383166 |
Aug 25, 1999 |
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08802195 |
Feb 14, 1997 |
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6071280 |
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08802195 |
Feb 14, 1997 |
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08515379 |
Aug 15, 1995 |
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5683384 |
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08515379 |
Aug 15, 1995 |
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08290031 |
Aug 12, 1994 |
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5536267 |
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08290031 |
Aug 12, 1994 |
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08148439 |
Nov 8, 1993 |
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5458597 |
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09513725 |
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09364203 |
Jul 30, 1999 |
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6663624 |
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09364203 |
Jul 30, 1999 |
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08623652 |
Mar 29, 1996 |
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5935123 |
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08623652 |
Mar 29, 1996 |
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08295166 |
Aug 24, 1994 |
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5599345 |
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08295166 |
Aug 24, 1994 |
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08148439 |
Nov 8, 1993 |
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5458597 |
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Current U.S.
Class: |
606/33 ;
606/41 |
Current CPC
Class: |
A61N 1/06 20130101; A61B
2018/00023 20130101; B22F 2999/00 20130101; A61B 2018/00779
20130101; A61B 18/1477 20130101; A61B 18/1492 20130101; A61B
2017/00026 20130101; A61B 2018/1472 20130101; A61B 2018/00273
20130101; A61B 18/1482 20130101; A61B 18/14 20130101; A61B
2018/00678 20130101; A61B 2018/00196 20130101; A61B 2018/00791
20130101; A61B 2018/00821 20130101; A61B 2218/002 20130101; A61M
25/007 20130101; A61N 1/403 20130101; A61N 5/04 20130101; A61B
2018/143 20130101; A61B 18/18 20130101; A61B 2018/162 20130101;
B22F 3/1216 20130101; A61B 18/1485 20130101; A61B 2017/00101
20130101; C22C 33/0285 20130101; A61B 2018/00761 20130101; A61B
2018/00827 20130101; A61B 18/1815 20130101; A61B 2018/00726
20130101; A61B 2018/1861 20130101; A61N 5/02 20130101; A61B
2018/00642 20130101; A61B 2018/00702 20130101; A61B 2018/00708
20130101; A61B 2018/1253 20130101; A61B 2018/1435 20130101; C22C
14/00 20130101; A61B 2018/126 20130101; A61B 2018/1432 20130101;
A61B 2018/00577 20130101; A61B 2018/00892 20130101; A61B 18/1206
20130101; A61B 2018/1425 20130101; A61B 2018/00476 20130101; A61N
5/045 20130101; A61B 2017/00084 20130101; C22C 1/0491 20130101;
A61B 2018/124 20130101; A61B 2018/00666 20130101; A61B 2018/00452
20130101; A61B 2018/00011 20130101; A61B 2018/00744 20130101; A61B
2018/00875 20130101; C22F 1/183 20130101; A61B 2018/00797 20130101;
A61B 18/1402 20130101; B22F 2999/00 20130101 |
Class at
Publication: |
606/033 ;
606/041 |
International
Class: |
A61B 018/18 |
Claims
What is claimed is:
1. A tissue ablation apparatus comprising: a delivery catheter
having a distal end and a proximal end; an electrode deployment
device positioned at least partially in the elongate member and
including at least one retractable electrode that is adapted to be
inserted into tissue, is adapted to penetrate tissue, and is
adapted to extend to a selected tissue site, said at least one
retractable electrode having a non-deployed state when positioned
in the elongate member, and being preformed to assume a curved
shape when deployed, and being operatively connected to a microwave
power source; and wherein the at least one electrode is advanceable
in and out of the distal most end of the elongate member.
2. The apparatus of claim 1, wherein the delivery catheter is
operatively coupled to an RF or a microwave power source.
3. The apparatus of claim 1, wherein the at least one electrode is
operatively coupled to an RF and a microwave power source or a
power source switchable between RF and microwave.
4. The apparatus of claim 3, wherein one of the delivery catheter
or the at least one electrode is operatively coupled to the RF
power source and the other is operatively coupled to the microwave
power source.
5. The apparatus of claim 1, further comprising: at least one
thermal sensor coupled to at least one of the at least one
electrodes.
6. The apparatus of claim 5, further comprising: a display for
displaying temperature values measured at the at least one
sensor.
7. The apparatus of claim 5, further comprising: a feedback control
system operatively coupled to the at least one sensor and the RF or
microwave power source.
8. The apparatus of claim 7, 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.
9. The apparatus of claim 7, 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 at least one electrode in response to the
temperature measured at the at least one sensor.
10. The apparatus of claim 1, wherein said at least one electrode
comprises at least two electrodes, each being operatively coupled
to the microwave power source, each of the at least two electrodes
having an energy delivery surface to create an ablation volume
between the energy delivery surfaces.
11. The apparatus of claim 1, wherein each of the at least one
electrodes include at least one thermal sensor.
12. The apparatus of claim 1, further comprising: an insulation
sleeve positioned in a surrounding relationship around at least a
portion of the at least one electrode.
13. The apparatus of claim 12, wherein the insulation sleeve is
adjustably moveable along an exterior of the at least one
electrode.
14. The apparatus of claim 1, wherein the at least one electrode is
hollow and coupled to an infusion medium source to receive an
infusion medium.
15. A method for creating an ablation volume in a selected tissue
mass, comprising: providing an ablation device with a delivery
catheter, at least one electrode being operatively coupled to a
microwave energy source, and at least one thermal sensor coupled to
at least one of the at least one electrodes; inserting the delivery
catheter into the selected tissue mass with the at least one
electrode distal end positioned in the delivery catheter lumen;
advancing the at least one electrode distal end out of the delivery
catheter lumen and into the selected tissue mass; delivering
electromagnetic energy from the microwave energy source to the at
least one electrode; and creating an ablation volume in the
selected tissue mass.
16. The method of claim 15, wherein said at least one electrode
comprises at least two electrodes, each having an energy delivery
surface, are advanced from the delivery catheter, and an ablation
volume is created between the two electrodes energy delivery
surfaces.
17. The method of claim 16, wherein the at least two electrodes are
advanced out of a distal end of the delivery catheter.
18. The method of claim 16, wherein the at least two electrodes are
advanced out of separate ports formed in the delivery catheter.
19. The method of claim 16, further comprising: delivering energy
from an energy source to the delivery catheter, wherein the
delivery catheter is operatively coupled to an energy source and
has an energy delivery surface.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to an apparatus for the
treatment and ablation of body masses, such as tumors, and more
particularly, to an RF treatment system suitable for multi-modality
treatment with an infusion delivery and a retractable multiple
needle electrode apparatus that surrounds an exterior of a tumor
with a plurality of needle electrodes and defines an ablative
volume. The system maintains a selected power at an electrode that
is independent of changes in current or voltage.
[0003] 2. Description of Related Art
[0004] 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 manor 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.
[0005] 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 cancer cell eradication by hyperthermia 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.
[0006] 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 body. Certain
techniques have been developed with microwave radiation and
ultrasound to focus energy at various desired depths. 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. Induction heating gives rise to poor
localization of the incident energy as well. Although induction
heating may be achieved by placing an antenna on the surface of the
body, superficial eddy currents are generated in the immediate
vicinity of the antenna. When it is driven using RF current
unwanted surface heating occurs diminishing heating to the
underlying tissue.
[0007] Thus, non-invasive procedures for providing heat to internal
tumors have had difficulties in achieving substantial specific and
selective treatment.
[0008] Hyperthermia, which can be produced from an RF or microwave
source, applies heat to tissue but does not exceed 45 degrees C. so
that normal cells survive. In thermotherapy, heat energy of greater
than 45 degrees C. is applied, resulting in histological damage,
desiccation and the denaturization of proteins. Hyperthermia has
been applied more recently for therapy of malignant tumors. In
hyperthermia, it is desirable to induce a state of hyperthermia
that is localized by interstitial current heating to a specific
area while concurrently insuring minimum thermal damage to healthy
surrounding tissue. Often, the tumor is located subcutaneously and
addressing the tumor requires either surgery, endoscopic procedures
or external radiation. It is difficult to externally induce
hyperthermia in deep body tissue because current density is diluted
due to its absorption by healthy tissue. Additionally, a portion of
the RF energy is reflected at the muscle/fat and bone interfaces
which adds to the problem of depositing a known quantity of energy
directly on a small tumor.
[0009] Attempts to use interstitial local hyperthermia have not
proven to be very successful. Results have often produced
nonuniform temperatures throughout the tumor. It is believed that
tumor mass reduction by hyperthermia is related the thermal dose.
Thermal dose is the minimum effective temperature applied
throughout the tumor mass for a defined period of time. Because
blood flow is the major mechanism of heat loss for tumors being
heated, and blood flow varies throughout the tumor, more even
heating of tumor tissue is needed to ensure more effective
treatment.
[0010] The same is true for ablation of the tumor itself through
the use of RF energy. Different methods have been utilized for the
RF ablation of masses such as tumors. Instead of heating the tumor
it is ablated through the application of energy. This process has
been difficult to achieve due to a variety of factors including,
(i) positioning of the RF ablation electrodes to effectively ablate
all of the mass, (ii) introduction of the RF ablation electrodes to
the tumor site and (iii) controlled delivery and monitoring of RF
energy to achieve successful ablation without damage to non-tumor
tissue.
[0011] There have been a number of different treatment methods and
devices for minimally invasively treating tumors. One such example
is an endoscope that produces RF hyperthermia in tumors, as
disclosed in U.S. Pat. No. 4,920,978. A microwave endoscope device
is described in U.S. Pat. No. 4,409,993. In U.S. Pat. No.
4,920,978, an endoscope for RF hyperthermia is disclosed.
[0012] In U.S. Pat. No. 4,763,671, a minimally invasive procedure
utilizes two catheters that are inserted interstitially into the
tumor. The catheters are placed within the tumor volume and each is
connect to a high frequency power source.
[0013] In U.S. Pat. No. 4,565,200, an electrode system is described
in which a single entrance tract cannula is used to introduce an
electrode into a selected body site.
[0014] However, as an effective treatment device, electrodes must
be properly positioned relative to the tumor. After the electrodes
are positioned, it is then desirable to have controlled application
and deposition of RF energy to ablate the tumor. This reduces
destruction of healthy tissue.
[0015] There is a need for a RF tumor treatment apparatus that is
useful for minimally invasive procedures. It would be desirable for
such a device to surround the exterior of the tumor with treatment
electrodes, defining a controlled ablation volume, and subsequently
the electrodes deliver a controlled amount of RF energy.
Additionally, there is a need for a device with infusion
capabilities during a pre-ablation step, and after ablation the
surrounding tissue can be preconditioned with electromagnetic
("EM") energy at hyperthermia temperatures less than 45 degrees.
This would provide for the synergistic affects of chemotherapy and
the instillation of a variety of fluids at the tumor site after
local ablation and hyperthermia.
SUMMARY OF THE INVENTION
[0016] In an embodiment of the invention, an infusion array
ablation apparatus includes an elongated delivery device having a
lumen and an infusion array positionable in the lumen. The infusion
array includes an RF electrode and at least a first and a second
infusion member. Each infusion member has a tissue piercing distal
portion and an infusion lumen. At least one of the first or second
infusion members is positionable in the elongated delivery device
in a compacted state and deployable from the elongated delivery
device with curvature in a deployed state. Also, at least one of
the first or second infusion members exhibits a changing direction
of travel when advanced from the elongated delivery device to a
selected tissue site. At least one infusion port is coupled to one
of the elongated delivery device, the infusion array, the first
infusion member or the second infusion member.
[0017] In another embodiment, a tissue ablation apparatus includes
a delivery catheter, with distal and proximal ends. A handle is
attached to the proximal end of the delivery catheter. An electrode
deployment apparatus is positioned at least partially in the
delivery catheter. It includes a plurality of electrodes that are
retractable in and out of the catheter's distal end. The electrodes
are in a non-deployed state when they are positioned within the
delivery catheter. As they are advanced out the distal end of the
catheter they become deployed, and define an ablation volume. Each
electrode has a first section with a first radius of curvature, and
a second section, extending beyond the first section, having a
second radius of curvature or a substantially linear geometry.
Alternatively, each deployed electrode has at least two radii of
curvature that are formed when the needle is advanced through the
delivery catheter's distal end and becomes positioned at a selected
tissue site. Also each deployed electrode can have at least one
radius of curvature in two or more planes. Further, the electrode
deployment apparatus can include at least one deployed electrode
having at least radii of curvature, and at least one deployed
electrode with at least one radius of curvature in two or more
planes.
[0018] In a further embodiment, the electrode deployment apparatus
has at least one deployed electrode with at least one curved
section that is located near the distal end of the delivery
catheter, and a non-curved section which extends beyond the curved
section of the deployed electrode. The electrode deployment
apparatus also has at least one deployed electrode with at least
two radii of curvature.
[0019] In another embodiment of the invention, each deployed
electrode has at least one curved section located near the distal
end of the delivery catheter, and a non-curved section that extends
beyond the curved section of the deployed electrode.
[0020] An electrode template can be positioned at the distal end of
the delivery catheter. It assists in guiding the deployment of the
electrodes to a surrounding relationship at an exterior of a
selected mass in a tissue. The electrodes can be hollow. An
adjustable electrode insulator can be positioned in an adjacent,
surrounding relationship to all or some of the electrodes. The
electrode insulator is adjustable, and capable of being advanced
and retracted along the electrodes in order to define an electrode
conductive surface.
[0021] The electrode deployment apparatus can include a cam which
advances and retracts the electrodes in and out of the delivery
catheter's distal end. Optionally included in the delivery catheter
are one or more guide tubes associated with one or more electrodes.
The guide tubes are positioned at the delivery catheter's distal
end.
[0022] Sources of infusing mediums, including but not limited to
electrolytic and chemotherapeutic solutions, can be associated with
the hollow electrodes. Electrodes can have sharpened, tapered ends
in order to assist their introduction. through tissue, and
advancement to the selected tissue site.
[0023] The electrode deployment apparatus is removable from the
delivery catheter. An obturator is initially positioned within the
delivery catheter. It can have a sharpened distal end. The delivery
catheter can be advanced percutaneously to an internal body organ,
or site, with the obturator positioned in the delivery catheter.
Once positioned, the obturator is removed, and the electrode
deployment apparatus is inserted into the delivery catheter. The
electrodes are in non-deployed states, and preferably compacted or
spring-loaded, while positioned within the delivery catheter. They
are made of a material with sufficient strength so that as the
electrodes emerge from the delivery catheter's distal end they are
deployed three dimensionally, in a lateral direction away from the
periphery of the delivery catheter's distal end. The electrodes
continue their lateral movement until the force applied by the
tissue causes the needles to change their direction of travel.
[0024] Each electrode now has either, (i) a first section with a
first radius of curvature, and a second section, extending beyond
the first section, having a second radius of curvature or a
substantially linear section, (ii) two radii of curvature, (iii)
one radius of curvature in two or more planes, or (iv) a
combination of two radii of curvature with one of them in two or
more planes. Additionally, the electrode deployment apparatus can
include one or more of these deployed geometries for the different
electrodes in the plurality. It is not necessary that every
electrode have the same deployed geometry.
[0025] After the electrodes are positioned around a mass, such as a
tumor, a variety of solutions, including but not limited to
electrolytic fluids, can be introduced through the electrodes to
the mass in a pre-ablation step. RF energy is applied, and the mass
is desiccated. In a post-ablation procedure, a chemotherapeutic
agent can then be introduced to the site, and the electrodes are
then retracted back into the introducing catheter. The entire
ablative apparatus can be removed, or additional ablative
treatments be conducted.
BRIEF DESCRIPTION OF THE FIGURES
[0026] FIG. 1 is a perspective view of the tissue ablation
apparatus of the invention, including a delivery catheter, handle,
and deployed electrodes.
[0027] FIG. 2 is a cross-sectional view of the tissue ablation
apparatus of the invention illustrated in FIG. 1.
[0028] FIG. 3 is a perspective view of an electrode of the
invention with two radii of curvature.
[0029] FIG. 4 is a perspective view of an electrode of the
invention with one radius of curvature in three planes.
[0030] FIG. 5 is a perspective view of an electrode of the
invention with one curved section, positioned close to the distal
end of the delivery catheter, and a linear section.
[0031] FIG. 6 is a perspective view of an electrode of the
invention with one curved section, positioned close to the distal
end of the delivery catheter, a generally first linear section, and
then a second linear section that continues laterally with regard
to the first linear section.
[0032] FIG. 7 is a cross-section view of a delivery catheter
associated with the invention, with guide tubes positioned at the
distal end of the delivery catheter.
[0033] FIG. 8 is a cross-sectional view of an electrode of the
invention.
[0034] FIG. 9 is a perspective view of the tissue ablation
apparatus of the invention shown in FIG. 1, with the delivery
catheter being introduced percutaneously through the body and
positioned at the exterior, or slightly piercing, a liver with a
tumor to be ablated.
[0035] FIG. 10 is a perspective view of the tissue ablation
apparatus of the invention with an obturator positioned in the
delivery catheter.
[0036] FIG. 11 is a perspective view of the tissue ablation
apparatus of the invention shown in FIG. 10, positioned in the body
adjacent to the liver, with the obturator removed.
[0037] FIG. 12 is a perspective view of the tissue ablation
apparatus of the invention shown in FIG. 10, positioned in the body
adjacent to the liver, and the electrode deployment apparatus, with
an electrode template, is positioned in the delivery catheter in
place of the obturator.
[0038] FIG. 13 is a perspective view of the ablation apparatus of
the invention, with deployed electrodes surrounding a tumor and
defining an ablation volume.
[0039] FIG. 14 is a perspective view of the tissue ablation
apparatus of the invention shown in FIG. 10, positioned in the body
adjacent to the liver, with deployed electrodes surrounding a tumor
and infusing a solution to the tumor site during a pre-ablation
procedure.
[0040] FIG. 15 is a perspective view of the tissue ablation
apparatus of the invention shown in FIG. 10, illustrating
application of RF energy to the tumor.
[0041] FIG. 16 is a perspective view of the tissue ablation
apparatus of the invention, illustrating the electro-desiccation of
the tumor.
[0042] FIG. 17 is a perspective view of the tissue ablation
apparatus of the invention, illustrating the instillation of
solutions to the tumor site during a post-ablation procedure.
[0043] FIG. 18 illustrates bipolar ablation between electrodes of
the invention.
[0044] FIG. 19 illustrates monopolar ablation between electrodes of
the invention.
[0045] FIG. 20 is a perspective view of an ablation system of the
invention, including RF and ultrasound modules, and a monitor.
[0046] FIG. 21 is a block diagram of the ablation system of the
invention.
[0047] FIG. 22(a) is a cross-sectional view of an RF treatment
apparatus of the invention.
[0048] FIG. 22(b) is a close up cross-sectional view of the distal
end of the RF treatment apparatus of FIG. 22(a).
[0049] FIG. 22(c) is a close up cross-sectional view of the RF
treatment apparatus of FIG. 22(a), illustrating the proximal end of
the insulation sleeve and a thermocouple associated with the
insulation sleeve.
[0050] FIG. 22(d) is a close up cross-sectional view of the RF
treatment apparatus of FIG. 22(a), illustrating the proximal end of
the RF treatment apparatus of FIG. 22(a).
[0051] FIG. 23 is an exploded view of an RF treatment apparatus of
the invention.
[0052] FIG. 24 is a cross-sectional view of the RF treatment
apparatus of the invention illustrating the electrode, insulation
sleeve and the associated thermal sensors.
[0053] FIG. 25(a) is a perspective view of the RF treatment
apparatus of the invention with the infusion device mounted at the
distal end of the catheter.
[0054] FIG. 25b is a perspective view of the RF treatment apparatus
of FIG. 25(a) illustrating the removal of the catheter, and
electrode attached to the distal end of the electrode, from the
infusion device which is left remaining in the body.
[0055] FIG. 26(a) is a perspective view of the RF treatment
apparatus of the invention with the electrode mounted at the distal
end of the catheter.
[0056] FIG. 26(b) is a perspective view of the RF treatment
apparatus of FIG. 26(a) illustrating the removal of the introducer
from the lumen of the electrode.
[0057] FIG. 27(a) is a perspective view of the RF treatment
apparatus of the invention with the introducer removed from the
lumen of the electrode.
[0058] FIG. 27(b) is a perspective view of the apparatus of FIG.
27(a) illustrating the removal of the electrode from the catheter,
leaving behind the insulation sleeve.
[0059] FIG. 28(a) is a perspective view of the RF ablation
apparatus of the invention with the insulation sleeve positioned in
a surrounding relationship to the electrode which is mounted to the
distal end of the catheter.
[0060] FIG. 28(b) is a perspective view of the RF ablation
apparatus of FIG. 28(a) illustrating the removal of the insulation
sleeve from the electrode.
[0061] FIG. 28(c) is a perspective view of the insulation sleeve
after it is removed from the electrode.
[0062] FIG. 29(a) is a perspective view illustrating the attachment
of a syringe to the device of FIG. 27(a).
[0063] FIG. 29(b) is a perspective view of a syringe, containing a
fluid medium such as a chemotherapeutic agent, attached to the RF
ablation apparatus of FIG. 27(a).
[0064] FIG. 30 is a block diagram of an RF treatment system of the
invention.
[0065] FIG. 31(a) is a schematic diagram of a power supply suitable
useful with the invention.
[0066] FIG. 31(b) is a schematic diagram of a voltage sensor
suitable useful with the invention.
[0067] FIG. 31(c) is a schematic diagram of a current sensor
suitable useful with the invention.
[0068] FIG. 31(d) is a schematic diagram of power computing
circuits suitable useful with the invention.
[0069] FIG. 31(e) is a schematic diagram of an impedance computing
circuit suitable useful with the invention.
[0070] FIG. 31(f) is a schematic diagram of a power control device
suitable useful with the invention.
[0071] FIG. 31(g) is a schematic diagram of an eight channel
temperature measurement suitable useful with the invention.
[0072] FIG. 31(h) is a schematic diagram of a power and temperature
control circuit useful with the invention.
[0073] FIG. 32 is a block diagram of an embodiment of the invention
which includes a microprocessor.
[0074] FIG. 33 illustrates the use of two RF treatment apparatus,
such as the one illustrated in FIG. 22(a), that are used in a
bipolar mode.
DETAILED DESCRIPTION
[0075] A tissue ablation apparatus 10 of the invention is
illustrated in FIG. 1. Ablation apparatus 10 includes a delivery
catheter 12, well known to those skilled in the art, with a
proximal end 14 and a distal end 16. Delivery catheter 12 can be of
the size of about 5 to 16 F. A handle 18 is removably attached to
proximal end 14. An electrode deployment device is at least
partially positioned within delivery catheter 12, and includes a
plurality of electrodes 20 that are retractable in and out of
distal end 16. Electrodes 20 can be of different sizes, shapes and
configurations. In one embodiment, they are needle electrodes, with
sizes in the range of 27 to 14 gauge. Electrodes 20 are in
non-deployed positions while retained in delivery catheter. In the
non-deployed positions, electrodes 20 may be in a compacted state,
spring loaded, generally confined or substantially straight if made
of a suitable memory metal such as nitinol. As electrodes 20 are
advanced out of distal end 16 they become distended in a deployed
state, which defines an ablative volume, from which tissue is
ablated as illustrated more fully in FIG. 2. Electrodes 20 operate
either in the bipolar or monopolar modes. When the electrodes are
used in the bipolar mode, the ablative volume is substantially
defined by the peripheries of the plurality of electrodes 20. In
one embodiment, the cross-sectional width of the ablative volume is
about 4 cm. However, it will be appreciated that different ablative
volumes can be achieved with tissue ablation apparatus 10.
[0076] The ablative volume is first determined to define a mass,
such as a tumor, to be ablated. Electrodes 20 are placed in a
surrounding relationship to a mass or tumor in a predetermined
pattern for volumetric ablation. An imaging system is used to first
define the volume of the tumor or selected mass. Suitable imaging
systems include but are not limited to, ultrasound, computerized
tomography (CT) scanning, X-ray film, X-ray fluoroscopy, magnetic
resonance imaging, electromagnetic imaging, and the like. The use
of such devices to define a volume of a tissue mass or a tumor is
well known to those skilled in the art.
[0077] With regard to the use of ultrasound, an ultrasound
transducer transmits ultrasound energy into a region of interest in
a patient's body. The ultrasound energy is reflected by different
organs and different tissue types. Reflected energy is sensed by
the transducer, and the resulting electrical signal is processed to
provide an image of the region of interest. In this way, the
ablation volume is then ascertained, and the appropriate electrode
deployment device is inserted into delivery catheter 12.
[0078] The ablative volume is substantially defined before ablation
apparatus 10 is introduced to an ablative treatment position. This
assists in the appropriate positioning of ablation apparatus 10. In
this manner, the volume of ablated tissue is reduced and
substantially limited to a defined mass or tumor, including a
certain area surrounding such a tumor, that is well controlled and
defined. A small area around the tumor is ablated in order to
ensure that all of the tumor is ablated.
[0079] With reference again to FIG. 2, electrode sections 20(a) are
in deployed states when they are introduced out of distal end 16.
Although electrodes 20 are generally in a non-distended
configuration in the non-deployed state while positioned in
delivery catheter 12, they can also be distended. Generally,
electrode sections 20(b) are in retained positions while they are
non-deployed. This is achieved by a variety of methods including
but not limited to, (i) the electrodes are pre-sprung, confined in
delivery catheter 12, and only become sprung (expanded) as they are
released from delivery catheter 12, (ii) the electrodes are made of
a memory metal, as explained in further detail below, (iii) the
electrodes are made of a selectable electrode material which gives
them an expanded shape outside of delivery catheter 12, or (iv)
delivery catheter 12 includes guide tubes which serve to confine
electrodes 12 within delivery catheter 12 and guide their direction
of travel outside of the catheter to form the desired, expanded
ablation volume. As shown in FIG. 2, electrodes 20 are pre-sprung
while retained in delivery catheter 12. This is the non-deployed
position. As they are advanced out of delivery catheter 12 and into
tissue, electrodes 20 become deployed and begin to "fan" out from
distal end 16, moving in a lateral direction relative to a
longitudinal axis of delivery catheter 12. As deployed electrodes
20 continue their advancement, the area of the fan increases and
extends beyond the diameter of distal end 16.
[0080] Significantly, each electrode 20 is distended in a deployed
position, and collectively, the deployed electrodes 20 define a
volume of tissue that will be ablated. As previously mentioned,
when it is desired to ablate a tumor, either benign or malignant,
it is preferable to ablate an area that is slightly in excess to
that defined by the exterior surface of the tumor. This improves
the chances that all of the tumor is eradicated.
[0081] Deployed electrodes 20 can have a variety of different
deployed geometries including but not limited to, (i) a first
section with a first radius of curvature, and a second section,
extending beyond the first section, having a second radius of
curvature or a substantially linear geometry, (ii) at least two
radii of curvature, (iii) at least one radius of curvature in two
or more planes, (iv) a curved section, with an elbow, that is
located near distal end 16 of delivery catheter, and a non-curved
section that extends beyond the curved section, or (v) a curved
section near distal end 16, a first linear section, and then
another curved section or a second linear section that is angled
with regard to the first linear section. Deployed electrodes 20
need not be parallel with respect to each other. The plurality of
deployed electrodes 20, which define a portion of the needle
electrode deployment device, can all have the same deployed
geometries, i.e., all with at least two radii of curvature, or a
variety of geometries, i.e., one with two radii of curvature, a
second one with one radius of curvature in two planes, and the rest
a curved section near distal end 16 of delivery catheter 12 and a
non-curved section beyond the curved section.
[0082] A cam 22, or other actuating device, can be positioned
within delivery catheter and used to advance and retract electrodes
20 in and out of delivery catheter 12. The actual movement of cam
can be controlled at handle 18. Suitable cams are of conventional
design, well known to those skilled in the art.
[0083] The different geometric configurations of electrodes 20 are
illustrated in FIGS. 3 through 6. In FIG. 3, electrode 20 has a
first radius of curvature 20(c) and a second radius of curvature
20(d). It can include more than two radii of curvature. As shown in
FIG. 4, electrode 20 has at least one radius of curvature which
extends to three planes. In FIG. 5, each electrode has a first
curved section 20(e) which is near distal end 16 of delivery
catheter 12. A first generally linear section 20(f) extends beyond
curved section 20(e), and the two meet at an elbow 20(g). The
electrodes 20 can serve as anodes and cathodes. The plurality of
electrodes 20 can have linear sections 20(f) that are generally
parallel to each other, or they can be non-parallel. FIG. 6
illustrates an electrode 20 that includes a first curved section
20(e) positioned near distal end 16 of delivery catheter 12, a
first linear section 20(f), and a second linear section 20(h) which
extends beyond first linear section 20(f). Section 20(h) can be
linear, curved, or a combination of the two. The plurality of
electrodes 20 illustrated in FIG. 6 can have parallel or
non-parallel first linear sections 20(f).
[0084] In one embodiment of the invention, electrodes 20 are
spring-loaded, and compacted in their non-deployed positions. As
electrodes 20 are advanced out of distal end 16 of delivery
catheter 12, they become deployed and fan out. Electrodes 20
continue this fanning out direction until the resistance of the
tissue overcomes the strength of the material forming electrode 20.
This causes electrode 20 to bend and move in a direction inward
relative to its initial outward fanning direction. The bending
creates curved sections 20(c) and 20(d) of FIG. 3, and can also
result in the formation of the other electrode 20 geometries of
FIGS. 4, 5 and 6. The extent of electrode 20 fan like travel is
dependent on the strength of the material from which it is made.
Suitable electrode materials include stainless steel, platinum,
gold, silver, copper and other electromagnetic conducting materials
including conductive polymers. Preferably, electrode 20 is made of
stainless steel or nickel titanium and has dimensions of about 27
to 14 gauge.
[0085] In one embodiment, electrode 20 is made of a memory metal,
such as nickel titanium, commercially available from Raychem
Corporation, Menlo Park, Calif. Additionally, a resistive heating
element can be positioned in an interior lumen of electrode 20.
Resistive heating element can be made of a suitable metal that
transfers heat to electrode 20, causing deployed electrode 20 to
become deflected when the temperature of electrode 20 reaches a
level that causes the electrode material, such as a memory metal,
to deflect, as is well known in the art. Not all of electrode 20
need be made of a memory metal. It is possible that only that
distal end portion of electrode 20, which is introduced into
tissue, be made of the memory metal in order to effect the desired
deployed geometrical configuration. Additionally, mechanical
devices, including but not limited to steering wires, can be
attached to the distal end of electrode 20 to cause it to become
directed, deflected and move about in a desired direction about the
tissue, until it reaches its final resting position to ablate a
tissue mass.
[0086] Optionally included in the delivery catheter are one or more
guide tubes 24, FIG. 7, which serve to direct the expansion of
electrodes 20 in the fan pattern as they are advanced out of distal
end 16 of the delivery catheter 12. Guide tubes 24 can be made of
stainless steel, spring steel and thermal plastics including but
not limited to nylon and polyesters, and are of sufficient size and
length to accommodate the electrodes to a specific site in the
body.
[0087] FIG. 8 illustrates one embodiment of electrode 20 with a
sharpened distal end 24. By including a tapered, or piercing end
24, the advancement of electrode 20 through tissue is easier.
Electrode 20 can be segmented, and include a plurality of fluid
distribution ports 26, which can be evenly formed around all or
only a portion of electrode 20. Fluid distribution ports 26 are
formed in electrode 20 when it is hollow and permit the
introduction and flow of a variety of fluidic mediums through
electrode 20 to a desired tissue site. Such fluidic mediums
include, but are not limited to, electrolytic solutions, pastes or
gels, as well as chemotherapeutic agents. Examples of suitable
conductive gels are carboxymethyl cellulose gels made from aqueous
electrolyte solutions such as physiological saline solutions, and
the like.
[0088] The size of fluid distribution ports 26 can vary, depending
on the size and shape of electrode 20. Also associated with
electrode 20 is an adjustable insulator sleeve 28 that is slidable
along an exterior surface of electrode 20. Insulator sleeve 28 is
advanced and retracted along electrode 20 in order to define the
size of a conductive surface of electrode 20. Insulator sleeve 28
is actuated at handle 18 by the physician, and its position along
electrode 20 is controlled. When electrode 20 moves out of delivery
catheter 12 and into tissue, insulator sleeve 28 can be positioned
around electrode 20 as it moves its way through the tissue.
Alternatively, insulator sleeve 28 can be advanced along a desired
length of electrode 20 after electrode 20 has been positioned
around a targeted mass to be ablated. Insulator sleeve is thus
capable of advancing through tissue along with electrode 20, or it
can move through tissue without electrode 20 providing the source
of movement. Thus, the desired ablation volume is defined by
deployed electrodes 20, as well as the positioning of insulator
sleeve 28 on each electrode. In this manner, a very precise
ablation volume is created. Suitable materials that form insulator
sleeve include but are not limited to nylon, polyimides, other
thermoplastics, and the like.
[0089] FIG. 9 illustrates a percutaneous application of tissue
ablation apparatus 10. Tissue ablation apparatus 10 can be used
percutaneously to introduce electrodes 20 to the selected tissue
mass or tumor. Electrodes 20 can remain in their non-deployed
positions while being introduced percutaneously into the body, and
delivered to a selected organ which contains the selected mass to
be ablated. Delivery catheter 12 is removable from handle 18. When
it is removed, electrode deployment device (the plurality of
electrodes 20) can be inserted and removed from delivery catheter
12. An obturator 30 is inserted into delivery catheter 12 initially
if a percutaneous procedure is to be performed. As shown in FIG.
10, obturator 30 can have a sharpened distal end 32 that pierces
tissue and assists the introduction of delivery catheter 12 to a
selected tissue site. The selected tissue site can be a body organ
with a tumor or other mass, or the actual tumor itself.
[0090] Obturator 30 is then removed from delivery catheter 12 (FIG.
11). Electrode deployment device is then inserted into delivery
catheter 12, and the catheter is then reattached to handle 18 (FIG.
12). As illustrated in FIG. 12, electrode deployment device can
optionally include an electrode template 34 to guide the deployment
of electrodes 20 to a surrounding relationship at an exterior of a
selected mass in the tissue.
[0091] Electrodes 20 are then advanced out of distal end 16 of
delivery catheter 12, and become deployed to form a desired
ablative volume which surrounds the mass. In FIG. 13, delivery
catheter 12 is positioned adjacent to the liver. Electrode
deployment device is introduced into delivery catheter 12 with
electrode template 34. Electrode deployment device now pierces the
liver, and cam 22 advances electrodes 20 out of delivery catheter
12 into deployed positions. Each individual electrode 20 pierces
the liver and travels through it until it is positioned in a
surrounding relationship to the tumor. The ablative volume is
selectable, and determined first by imaging the area to be ablated.
The ablative volume is defined by the peripheries of all of the
deployed electrodes 20 that surround the exterior of the tumor.
Once the volume of ablation is determined, then an electrode set is
selected which will become deployed to define the ablation volume.
A variety of different factors are important in creating an
ablation volume. Primarily, different electrodes 20 will have
various degrees of deployment, based on type of electrode material,
the level of pre-springing of the electrodes and the geometric
configuration of the electrodes in their deployed states. Tissue
ablation apparatus 10 permits different electrode 20 sets to be
inserted into delivery catheter 12, in order to define a variety of
ablation volumes.
[0092] Prior to ablation of the tumor, a pre-ablation step can be
performed. A variety of different solutions, including electrolytic
solutions such as saline, can be introduced to the tumor site, as
shown in FIG. 14. FIG. 15 illustrates the application of RF energy
to the tumor. Electrode insulator 28 is positioned on portions of
electrodes 20 where there will be no ablation. This further defines
the ablation volume. The actual electro-desiccation of the tumor,
or other targeted masses or tissues, is shown in FIG. 16. Again,
deployed electrodes 20, with their electrode insulators 28
positioned along sections of the electrodes, define the ablation
volume, and the resulting amount of mass that is desiccated.
[0093] Optionally following desiccation, electrodes 20 can
introduce a variety of solutions in a post-ablation process. This
step is illustrated in FIG. 17. Suitable solutions include but are
not limited to chemotherapeutic agents.
[0094] FIG. 8 illustrates tissue ablation apparatus 10 operated in
a bipolar mode. Its monopolar operation is shown in FIG. 19. Each
of the plurality of electrodes 20 can play different roles in the
ablation process. There can be polarity shifting between the
different electrodes.
[0095] A tissue ablation system 36, which can be modular, is shown
in FIG. 20 and can include a display 38. Tissue ablation system 36
can also include an RF energy source, microwave source, ultrasound
source, visualization devices such as cameras and VCR's,
electrolytic and chemotherapeutic solution sources, and a
controller which can be used to monitor temperature or impedance.
One of the deployed electrodes 20 can be a microwave antenna
coupled to a microwave source. This electrode can initially be
coupled to RF power source 42 and is then switched to the microwave
source
[0096] Referring now to FIG. 21, a power supply 40 delivers energy
into RF power generator (source) 42 and then to electrodes 20 of
tissue ablation apparatus 10. A multiplexer 46 measures current,
voltage and temperature (at numerous temperature sensors which can
be positioned on electrodes 20). Multiplexer 46 is driven by a
controller 48, which can be a digital or analog controller, or a
computer with software. When controller 48 is a computer, it can
include a CPU coupled through a system bus. This system can include
a keyboard, disk drive, or other non-volatile memory systems, a
display, and other peripherals, as known in the art. Also coupled
to the bus are a program memory and a data memory.
[0097] An operator interface 50 includes operator controls 52 and
display 38. Controller 48 is coupled to imaging systems, including
ultrasound transducers, temperature sensors, and viewing optics and
optical fibers, if included.
[0098] Current and voltage are used to calculate impedance.
Diagnostics are done through ultrasound, CT scanning, or other
methods known in the art. Imaging can be performed before, during
and after treatment.
[0099] Temperature sensors measure voltage and current that is
delivered. The output of these sensors is used by controller 48 to
control the delivery of RF power. Controller 48 can also control
temperature and power. The amount of RF energy delivered controls
the amount of power. A profile of power delivered can be
incorporated in controller 38, as well as a pre-set amount of
energy to be delivered can also be profiled.
[0100] Feedback can be the measurement of impedance or temperature,
and occurs either at controller 48 or at electromagnetic energy
source 42, e.g., RF or microwave, if it incorporates a controller.
For impedance measurement, this can be achieved by supplying a
small amount of non-ablation RF energy. Voltage and current are
then measured.
[0101] Circuitry, software and feedback to controller 48 result in
process control and are used to change, (i) power, including RF,
ultrasound, and the like, (ii) the duty cycle (on-off and wattage),
(iii) monopolar or bipolar energy delivery, (iv) and electrolytic
solution delivery, flow rate and pressure and (v) determine when
ablation is completed through time, temperature and/or impedance.
These process variables can be controlled and varied based on
temperature monitored at multiple sites, and impedance to current
flow that is monitored, indicating changes in current carrying
capability of the tissue during the ablative process.
[0102] Referring now to FIGS. 22(a)) 22(b), 22(c), 22 and 24 an RF
treatment apparatus 110 is illustrated which can be used to ablate
a selected tissue mass, including but not limited to a tumor, or
treat the mass by hyperthermia. Treatment apparatus 110 includes a
catheter 112 with a catheter lumen in which different devices are
introduced and removed. An insert 114 is removably positioned in
the catheter lumen. Insert 114 can be an introducer, a needle
electrode, and the like.
[0103] When insert 114 is an introducer, including but not limited
to a guiding or delivery catheter, it is used as a means for
puncturing the skin of the body, and advancing catheter 112 to a
desired site. Alternatively, insert 114 can be both an introducer
and an electrode adapted to receive RF current for tissue ablation
and hyperthermia.
[0104] If insert 114 is not an electrode, then a removable
electrode 116 is positioned in insert 114 either during or after
treatment apparatus 110 has been introduced percutaneously to the
desired tissue site. Electrode 116 has an electrode distal end that
advances out of an insert distal end. In this deployed position, RF
energy is introduced to the tissue site along a conductive surface
of electrode 116.
[0105] Electrode 116 can be included in treatment apparatus 110,
and positioned within insert 114, while treatment apparatus 110 is
being introduced to the desired tissue site. The distal end of
electrode 116 can have substantially the same geometry as the
distal end of insert 114 so that the two ends are essentially
flush. Distal end of electrode 116, when positioned in insert 114
as it is introduced through the body, serves to block material from
entering the lumen of insert 114. The distal end of electrode 116
essentially can provide a plug type of function.
[0106] Electrode 116 is then advanced out of a distal end of insert
114, and the length of an electrode conductive surface is defined,
as explained further in this specification. Electrode 116 can
advance out straight, laterally or in a curved manner out of distal
end of insert 114. Ablative or hyperthermia treatment begins when
two electrodes 116 are positioned closely enough to effect bipolar
treatment of the desired tissue site or tumor. A return electrode
attaches to the patients skin. Operating in a bipolar mode,
selective ablation of the tumor is achieved. However, it will be
appreciated that the present invention is suitable for treating,
through hyperthermia or ablation, different sizes of tumors or
masses. The delivery of RF energy is controlled and the power at
each electrode is maintained, independent of changes in voltage or
current. Energy is delivered slowly at low power. This minimizes
desiccation of the tissue adjacent to the electrodes 116,
permitting a wider area of even ablation. In one embodiment, 8 to
14 W of RF energy is applied in a bipolar mode for 10 to 25
minutes. An ablation area between electrodes 116 of about 2 to 6 cm
is achieved.
[0107] Treatment apparatus 110 can also include a removable
introducer 118 which is positioned in the insert lumen instead of
electrode 116. Introducer 118 has an introducer distal end that
also serves as a plug, to minimize the entrance of material into
the insert distal end as it advances through a body structure.
Introducer 118 is initially included in treatment apparatus, and is
housed in the lumen of insert 114, to assist the introduction of
treatment apparatus 110 to the desired tissue site. Once treatment
apparatus 110 is at the desired tissue site, then introducer 118 is
removed from the insert lumen, and electrode 116 is substituted in
its place. In this regard, introducer 118 and electrode 116 are
removable to and from insert 114.
[0108] Also included is an insulator sleeve 120 coupled to an
insulator slide 122. Insulator sleeve 120 is positioned in a
surrounding relationship to electrode 116. Insulator slide 122
imparts a slidable movement of the insulator sleeve along a
longitudinal axis of electrode 116 in order to define an electrode
conductive surface what begins at an insulator sleeve distal
end.
[0109] A thermal sensor 124 can be positioned in or on electrode
116 or introducer 118. A thermal sensor 126 is positioned on
insulator sleeve 120. In one embodiment, thermal sensor 124 is
located at the distal end of introducer 118, and thermal sensor 126
is located at the distal end of insulator sleeve 120, at an
interior wall which defines a lumen of insulator sleeve 120.
Suitable thermal sensors include a T type thermocouple with copper
constantene, J type, E type, K type, thermistors, fiber optics,
resistive wires, thermocouples IR detectors, and the like. It will
be appreciated that sensors 124 and 126 need not be thermal
sensors. Catheter 112, insert 114, electrode 116 and introducer 118
can be made of a variety of materials. In one embodiment, catheter
112 is black anodizid aluminum, 0.5 inch, electrode 116 is made of
stainless steel, 18 gauge, introducer 118 is made of stainless
steel, 21 gauge, and insulator sleeve 120 is made of polyimide.
[0110] By monitoring temperature, RF power delivery can be
accelerated to a predetermined or desired level. Impedance is used
to monitor voltage and current. The readings of thermal sensors 124
and 126 are used to regulate voltage and current that is delivered
to the tissue site. The output for these sensors is used by a
controller, described further in this specification, to control the
delivery of RF energy to the tissue site. Resources, which can be
hardware and/or software, are associated with an RF power source,
coupled to electrode 116 and the return electrode. The resources
are associated with thermal sensors 124 and 125, the return
electrode as well as the RF power source for maintaining a selected
power at electrode 116 independent of changes in voltage or
current. Thermal sensors 124 and 126 are of conventional design,
including but not limited to thermistors, thermocouples, resistive
wires, and the like.
[0111] Electrode 116 is preferably hollow and includes a plurality
of fluid distribution ports 128 from which a variety of fluids can
be introduced, including electrolytic solutions, chemotherapeutic
agents, and infusion media.
[0112] A specific embodiment of the RF treatment device 110 is
illustrated in FIG. 23. Included is an electrode locking cap 128,
an RF coupler 310, an introducer locking cap 312, insulator slide
122, catheter body 112, insulator retainer cap 134, insulator
locking sleeve 136, a luer connector 138, an insulator elbow
connector 140, an insulator adjustment screw 142, a thermocouple
cable 144 for thermal sensor 126, a thermocouple cable 46 for
thermal sensor 124 and a luer retainer 148 for an infusion device
150.
[0113] In another embodiment of RF treatment apparatus 110,
electrode 116 is directly attached to catheter 112 without insert
114. Introducer 118 is slidably positioned in the lumen of
electrode 116. Insulator sleeve 120 is again positioned in a
surrounding relationship to electrode 116 and is slidably moveable
along its surface in order to define the conductive surface.
Thermal sensors 124 and 126 are positioned at the distal ends of
introducer 118 and insulator sleeve 120. Alternatively, thermal
sensor 124 can be positioned on electrode 116, such as at its
distal end. The distal ends of electrode 16 and introducer 118 can
be sharpened and tapered. This assists in the introduction of RF
treatment apparatus to the desired tissue site. Each of the two
distal ends can have geometries that essentially match.
Additionally, distal end of introducer 118 can an essentially solid
end in order to prevent the introduction of material into the lumen
of catheter 116.
[0114] In yet another embodiment of RF treatment apparatus 110,
infusion device 150 remains implanted in the body after catheter
112, electrode 116 and introducer 118 are all removed. This permits
a chemotherapeutic agent, or other infusion medium, to be easily
introduced to the tissue site over an extended period of time
without the other devices of RF treatment apparatus 10 present.
These other devices, such as electrode 116, can be inserted through
infusion device 150 to the tissue site at a later time for
hyperthermia or ablation purposes. Infusion device 150 has an
infusion device lumen and catheter 112 is at least partially
positioned in the infusion device lumen. Electrode 116 is
positioned in the catheter lumen, in a fixed relationship to
catheter 112, but is removable from the lumen. Insulator sleeve 120
is slidably positioned along a longitudinal axis of electrode 116.
Introducer 118 is positioned in a lumen of electrode 116 and is
removable therefrom. A power source is coupled to electrode 116.
Resources are associated with thermal sensors 124 and 126, voltage
and current sensors that are coupled to the RF power source for
maintaining a selected power at electrode 116.
[0115] The distal end of RF treatment apparatus 110 is shown in
FIG. 22(b). Introducer 118 is positioned in the lumen of electrode
116, which can be surrounded by insulator sleeve 120, all of which
are essentially placed in the lumen of infusion device 150. It will
be appreciated, however, that in FIG. 22(b) insert 114 can take the
place of electrode 116, and electrode 116 can be substituted for
introducer 118.
[0116] The distal end of insulator sleeve 120 is illustrated in
FIG. 22(c). Thermal sensor 126 is shown as being in the form of a
thermocouple. In FIG. 22(d), thermal sensor 124 is also illustrated
as a thermocouple that extends beyond a distal end of introducer
118, or alternative a distal end of electrode 116.
[0117] Referring now to FIGS. 25(a) and 25(b), infusion device 150
is attached to the distal end of catheter 112 and retained by a
collar. The collar is rotated, causing catheter 112 to become
disengaged from infusion device 150. Electrode 116 is attached to
the distal end of catheter 112. Catheter 112 is pulled away from
infusion device 150, which also removes electrode 116 from infusion
device 150. Thereafter, only infusion device 150 is retained in the
body. While it remains placed, chemotherapeutic agents can be
introduced through infusion device 150 to treat the tumor site.
Additionally, by leaving infusion device 150 in place, catheter 112
with electrode 116 can be reintroduced back into the lumen of
infusion device 150 at a later time for additional RF treatment in
the form of ablation or hyperthermia.
[0118] In FIG. 26(a), electrode 116 is shown as attached to the
distal end of catheter 112. Introducer 118 is attached to
introducer locking cap 132 which is rotated and pulled away from
catheter 112. As shown in FIG. 26(b) this removes introducer 118
from the lumen of electrode 116.
[0119] Referring now to FIG. 27(a), electrode 116 is at least
partially positioned in the lumen of catheter 112. Electrode
locking cap 128 is mounted at the proximal end of catheter 112,
with the proximal end of electrode 116 attaching to electrode
locking cap 128. Electrode locking cap 128 is rotated and unlocks
from catheter 112. In FIG. 27(b), electrode locking cap 128 is then
pulled away from the proximal end of catheter 112, pulling with it
electrode 116 which is then removed from the lumen of catheter 112.
After electrode 116 is removed from catheter 112, insulator sleeve
120 is locked on catheter 112 by insulator retainer cap 134.
[0120] In FIG. 28(a), insulator retainer cap 134 is unlocked and
removed from catheter 112. As shown in FIG. 28(b), insulator sleeve
120 is then slid off of electrode 116. FIG. 28(c) illustrates
insulator sleeve 120 completely removed from catheter 112 and
electrode 116.
[0121] Referring now to FIGS. 29(a) and 29(b), after introducer 118
is removed from catheter 112, a fluid source, such as syringe 151,
delivering a suitable fluid, including but not limited to a
chemotherapeutic agent, attaches to luer connector 138 at the
proximal end of catheter 112. Chemotherapeutic agents are then
delivered from syringe 151 through electrode 116 to the tumor site.
Syringe 151 is then removed from catheter 112 by imparting a
rotational movement of syringe 151 and pulling it away from
catheter 112. Thereafter, electrode 116 can deliver further RF
power to the tumor site. Additionally, electrode 116 and catheter
112 can be removed, leaving only infusion device 150 in the body.
Syringe 151 can then be attached directly to infusion device 150 to
introduce a chemotherapeutic agent to the tumor site.
Alternatively, other fluid delivery devices can be coupled to
infusion device 150 in order to have a more sustained supply of
chemotherapeutic agents to the tumor site.
[0122] Once chemotherapy is completed, electrode 116 and catheter
112 can be introduced through infusion device 150. RF power is then
delivered to the tumor site. The process begins again with the
subsequent removal of catheter 112 and electrode 116 from infusion
device 150. Chemotherapy can then begin. Once it is complete,
further RF power can be delivered to the tumor site. This process
can be repeated any number of times for an effective multi-modality
treatment of the tumor site.
[0123] Referring now to FIG. 30, a block diagram of power source
152 is illustrated. Power source 152 includes a power supply 154,
power circuits 156, a controller 158, a power and impedance
calculation device 160, a current sensor 162, a voltage sensor 164,
a temperature measurement device 166 and a user interface and
display 168.
[0124] FIGS. 31(a) through 31(g) are schematic diagrams of power
supply 154, voltage sensor 164, current sensor 162, power computing
circuit associated with power and impedance calculation device 160,
impedance computing circuit associated with power and impedance
calculation device 160, power control circuit of controller 158 and
an eight channel temperature measurement circuit of temperature
measure device 166, respectively.
[0125] Current delivered through each electrode 116 is measured by
current sensor 162. Voltage between the electrodes 116 is measured
by voltage sensor 164. Impedance and power are then calculated at
power and impedance calculation device 160. These values can then
be displayed at user interface 168. Signals representative of power
and impedance values are received by controller 158.
[0126] A control signal is generated by controller 158 that is
proportional to the difference between an actual measured value,
and a desired value. The control signal is used by power circuits
156 to adjust the power output in an appropriate amount in order to
maintain the desired power delivered at the respective electrode
116.
[0127] In a similar manner, temperatures detected at thermal
sensors 124 and 126 provide feedback for maintaining a selected
power. The actual temperatures are measured at temperature
measurement device 166, and the temperatures are displayed at user
interface 168. Referring now to FIG. 31(h), a control signal is
generated by controller 159 that is proportional to the difference
between an actual measured temperature, and a desired temperature.
The control signal is used by power circuits 157 to adjust the
power output in an appropriate amount in order to maintain the
desired temperature delivered at the respective sensor 124 or
126.
[0128] Controller 158 can be a digital or analog controller, or a
computer with software. When controller 158 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.
[0129] User interface 168 includes operator controls and a display.
Controller 158 can be coupled to imaging systems, including but not
limited to ultrasound, CT scanners and the like.
[0130] Current and voltage are used to calculate impedance.
Diagnostics can be performed optically, with ultrasound, CT
scanning, and the like. Diagnostics are performed either before,
during and after treatment.
[0131] The output of current sensor 162 and voltage sensor 164 is
used by controller 158 to maintain the selected power level at
electrodes 116. The amount of RF energy delivered controls the
amount of power. A profile of power delivered can be incorporated
in controller 158, and a pre-set amount of energy to be delivered
can also be profiled.
[0132] Circuitry, software and feedback to controller 158 result in
process control, and the maintenance of the selected power that is
independent of changes in voltage or current, and are used to
change, (i) the selected power, including RF, ultrasound and the
like, (ii) the duty cycle (on-off and wattage), (iii) bipolar
energy delivery and (iv) fluid delivery, including chemotherapeutic
agents, 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 thermal sensors 124 and 126 at multiple
sites.
[0133] Controller 158 can be microprocessor controlled. Referring
now to FIG. 32, current sensor 162 and voltage sensor 164 are
connected to the input of an analog amplifier 170. Analog amplifier
170 can be a conventional differential amplifier circuit for use
with thermal sensors 124 and 126. The output of analog amplifier
170 is sequentially connected by an analog multiplexer 172 to the
input of analog-to-digital converter 174. The output of analog
amplifier 170 is a voltage which represents the respective sensed
temperatures. Digitized amplifier output voltages are supplied by
analog-to-digital converter 174 to a microprocessor 176.
Microprocessor 176 may be a type 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.
[0134] Microprocessor 176 sequentially receives and stores digital
representations of impedance and temperature. Each digital value
received by microprocessor 176 corresponds to different
temperatures and impedances.
[0135] Calculated power and impedance values can be indicated on
user interface 168. Alternatively, or in addition to the numerical
indication of power or impedance, calculated impedance and power
values can be compared by microprocessor 176 with power and
impedance limits. When the values exceed predetermined power or
impedance values, a warning can be given on interface 168, and
additionally, the delivery of RF energy can be reduced, modified or
interrupted. A control signal from microprocessor 176 can modify
the power level supplied by power supply 154.
[0136] An imaging system can be used to first define the volume of
the tumor or selected mass. Suitable imaging systems include but
are not limited to, ultrasound, CT scanning, X-ray film, X-ray
fluoroscope, magnetic resonance imaging, electromagnetic imaging
and the like. The use of such devices to define a volume of a
tissue mass or a tumor is well known to those skilled in the
art.
[0137] Specifically with ultrasound, an ultrasound transducer
transmits ultrasound energy into a region of interest in a
patient's body. The ultrasound energy is reflected by different
organs and different tissue types. Reflected energy is sensed by
the transducer, and the resulting electrical signal is processed to
provide an image of the region of interest. In this way, the volume
to be ablated is ascertained.
[0138] Ultrasound is employed to image the selected mass or tumor.
This image is then imported to user interface 168. The placement of
electrodes 116 can be marked, and RF energy delivered to the
selected site with prior treatment planning. Ultrasound can be used
for real time imaging. Tissue characterization of the imaging can
be utilized to determine how much of the tissue is heated. This
process can be monitored. The amount of RF power delivered is low,
and the ablation or hyperthermia of the tissue is slow. Desiccation
of tissue between the tissue and each needle 116 is minimized by
operating at low power.
[0139] The following examples illustrate the use of the invention
with two RF treatment apparatus with two electrodes shown in FIG.
33, or a pair of two electrodes, that are used in a bipolar mode to
ablate tissue.
EXAMPLE 1
[0140]
1 Exposed electrode length: 1.5 cm Distance between electrodes: 1.5
cm Power setting: 5 W Ablation time: 10 min. Lesion size: width: 2
cm length: 1.7 cm depth: 1.5 cm
EXAMPLE 2
[0141]
2 Exposed electrode length: 1.5 Distance between electrodes: 2.0
Power setting: 7.0 Ablation time: 10 min. Lesion size: width: 2.8
cm length: 2.5 cm depth: 2.2 cm
EXAMPLE 3
[0142]
3 Exposed electrode length: 2.5 cm Distance between electrodes: 2.0
cm Power setting: 10 W Ablation time: 10 min Lesion size: width:
3.0 cm length: 2.7 cm depth: 1.7 cm
EXAMPLE 4
[0143]
4 Exposed electrode length: 2.5 cm Distance between electrodes: 2.5
cm Power setting: 8 W Ablation time: 10 min. Lesion size: width:
2.8 cm length: 2.7 cm depth: 3.0 cm
EXAMPLE 5
[0144]
5 Exposed electrode length: 2.5 cm Distance between electrodes: 2.5
cm Power setting: 8 W Ablation time: 12 min. Lesion size: width:
2.8 cm length: 2.8 cm depth: 2.5 cm
EXAMPLE 6
[0145]
6 Exposed electrode length: 2.5 cm Distance between electrodes: 1.5
cm Power setting: 8 W Ablation time: 14 min. Lesion size: width:
3.0 cm length: 3.0 cm depth: 2.0 cm
EXAMPLE 7
[0146]
7 With return electrode at 1.5 cm Exposed electrode length: 2.5 cm
Distance between electrodes: 2.5 cm Power setting: 8 W Ablation
time: 10 min. Lesion size: width: 3.0 cm length: 3.0 cm depth: 3.0
cm
EXAMPLE 8
[0147]
8 Exposed electrode length: 2.5 cm Distance between electrodes: 2.5
cm Power setting: 10 W Ablation time: 12 min. Lesion size: width:
3.5 cm length: 3.0 cm depth: 2.3 cm
EXAMPLE 9
[0148]
9 Exposed electrode length: 2.5 cm Distance between electrodes: 2.5
cm Power setting: 11 W Ablation time: 11 min. Lesion size: width:
3.5 cm length: 3.5 cm depth: 2.5 cm
EXAMPLE 10
[0149]
10 Exposed electrode length: 3.0 cm Distance between electrodes:
3.0 cm Power setting: 11 W Ablation time: 15 min. Lesion size:
width: 4.3 cm length: 3.0 cm depth: 2.2 cm
EXAMPLE 11
[0150]
11 Exposed electrode length: 3.0 cm Distance between electrodes:
2.5 cm Power setting: 11 W Ablation time: 11 min. Lesion size:
width: 4.0 cm length: 3.0 cm depth: 2.2 cm
EXAMPLE 12
[0151]
12 Exposed electrode length: 4.0 cm Distance between electrodes:
2.5 cm Power setting: 11 W Ablation time: 16 min. Lesion size:
width: 3.5 cm length: 4.0 cm depth: 2.8 cm
EXAMPLE 13
[0152]
13 Two pairs of electrodes (Four electrodes) Exposed electrode
length: 2.5 cm Distance between electrodes: 2.5 cm Power setting:
12 W Ablation time: 16 min. Lesion size: width: 3.5 cm length: 3.0
cm depth: 4.5 cm
EXAMPLE 14
[0153]
14 Two pairs of electrodes (Four electrodes) Exposed electrode
length: 2.5 cm Distance between electrodes: 2.5 cm Power setting:
15 W Ablation time: 14 min. Lesion size: width: 4.0 cm length: 3.0
cm depth: 5.0 cm
[0154] The foregoing description of preferred embodiments of the
present invention has been provided for the 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, variations and different
combinations of embodiments will be apparent to practitioners
skilled in this art. Also, it will be apparent to the skilled
practitioner that elements from one embodiment can be recombined
with one or more other embodiments. It is intended that the scope
of the invention be defined by the following claims and their
equivalents.
* * * * *