U.S. patent application number 12/193949 was filed with the patent office on 2009-02-12 for cryogenic system.
This patent application is currently assigned to ENDOCARE, INC.. Invention is credited to JOHN G. BAUST, ROY CHEEKS.
Application Number | 20090043297 12/193949 |
Document ID | / |
Family ID | 35376193 |
Filed Date | 2009-02-12 |
United States Patent
Application |
20090043297 |
Kind Code |
A1 |
BAUST; JOHN G. ; et
al. |
February 12, 2009 |
CRYOGENIC SYSTEM
Abstract
A cryosurgical system and method for supplying cryogen to a
probe. The system including a container filled with cryogen and
having bellows of a pump submerged within said cryogen. Conduits
fluidly interconnect the bellows and a probe that is outside the
container to permit the cryogen to be forced from the bellows to
the probe upon activation of pump. A pressure relief valve is
fluidly coupled to the conduits and positioned between the bellows
and the probe. After initially forcing cryogen to the probe at a
pressure that establishes a colligative-based sub-cooling of the
liquid cryogen, the pressure relief valve is activated to lower the
pressure of the cryogen to a running pressure.
Inventors: |
BAUST; JOHN G.; (Candor,
NY) ; CHEEKS; ROY; (Harpers Ferry, NY) |
Correspondence
Address: |
LAWRENCE N. GINSBERG
ENDOCARE, INC., 201 TECHNOLOGY DRIVE
IRVINE
CA
92618
US
|
Assignee: |
ENDOCARE, INC.
Irvine
CA
|
Family ID: |
35376193 |
Appl. No.: |
12/193949 |
Filed: |
August 19, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11688007 |
Mar 19, 2007 |
7416548 |
|
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12193949 |
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10478937 |
May 14, 2004 |
7192426 |
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PCT/US02/17104 |
May 31, 2002 |
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11688007 |
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60294256 |
May 31, 2001 |
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Current U.S.
Class: |
606/23 |
Current CPC
Class: |
A61B 18/02 20130101 |
Class at
Publication: |
606/23 |
International
Class: |
A61B 18/02 20060101
A61B018/02 |
Claims
1. A cryosurgical system, comprising: a container having cryogen
within said container; a pump having a piston, said piston being
submerged within said cryogen within said container; a probe
outside the container for use in cryosurgical procedures; and, a
system of conduits fluidly interconnecting said piston and said
probe permitting said cryogen to be forced from said piston to said
probe upon activation of said piston.
2. A system according to claim 1, wherein said cryogen is liquid
nitrogen.
3. A system according to claim 1, wherein said piston is a
bellows.
4. A pump assembly for a cryosurgical system, comprising: a driving
mechanism coupled to an elongated drive shaft; a bellows coupled to
said drive shaft and adapted to be submersed in cryogen, said
bellows formed from metal; a one-way inlet valve fluidly coupled to
said bellows; and a one-way outlet valve fluidly coupled to said
bellows.
5. A pump assembly according to claim 4, further comprising: a
supply manifold fluidly coupled with said outlet valve, said supply
and manifold having a plurality of ports.
6. A method of delivering cryogen to a surgical device, comprising:
providing a container having cryogen within the container;
providing a pump having a piston within a cylinder, said piston
being submerged within the cryogen within said container; providing
a surgical instrument outside the container for use in cryosurgical
procedures; providing a system of conduits fluidly interconnecting
the piston and the surgical device permitting the cryogen to be
forced from the piston to the probe upon activation of the piston;
activating the piston to pull cryogen within the cylinder; and,
activating the piston to pull the cryogen from the cylinder to the
surgical device to an initial predetermined pressure.
7. A method according to claim 6 wherein the activating the piston
to push the cryogen from the cylinder to the surgical device to an
initial predetermined pressure includes pushing the cryogen to the
surgical instrument at a pressure of between approximately 250
pounds per square inch and approximately 400 pounds per square
inch.
8. A method according to claim 6 wherein after pushing the cryogen
to the surgical device at the initial predetermined pressure,
activating the pressure release device to decrease the pressure of
the cryogen to a lower pressure that is below the predetermined
pressure.
9. A system according to claim 1, further including a pressure
relief device fluidly coupled to said systems of conduits and
positioned between said pump and said probe.
10. A method according to claim 6, further including the step of:
providing a pressure relief device fluidly coupled to the systems
of conduits and positioned between the bellows and the probe.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. Ser. No. 11/688,007 entitled
Cryogenic System, filed Mar. 19, 2007, which claims benefit of U.S.
Ser. No. 10/478,937 (now U.S. Pat. No. 7,192,426) entitled
Cryogenic System, filed May 14, 2004, which claims the benefit of
PCT Application No. PCT/US02/17104, filed May 31, 2002, which
claims the benefit of U.S. Provisional Application Ser. No.
60/294,256, filed on May 31, 2001. The entire contents of U.S. Ser.
No. 10/478,937, PCT Application No. PCT/US02/17104 (WO 02/096270),
and U.S. Ser. No. 60/294,256 are incorporated herein by reference
thereto.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a cryogenic system. More
specifically, illustrative embodiments of the present invention
relate to a cryogenic system for use in cryosurgical
procedures.
[0004] 2. Description of the Related Art
[0005] The distribution of boiling (liquid) cryogens, such as
liquid nitrogen, is problematic due to the parasitic heat load
provided by a cryosurgical device's plumbing or transport circuit,
which is maintained at ambient temperature. Pre-cooling the
plumbing circuit, even if adequately insulated, causes two-phase
flow (liquid-gas mixtures), cryogen boil-off, and choking flow due
to gas expansion in the transport circuit. As a result, target
temperatures at the distal end of the flow path (i.e., cryoprobe
tip) are not reached for many minutes.
[0006] Some prior cryogenic systems and devices are disclosed in
U.S. Pat. No. 4,345,598 to Zobac et al.; U.S. Pat. No. 4,472,946 to
Zwick; U.S. Pat. No. 4,860,545 to Zwick et al.; U.S. Pat. No.
4,946,460 to Merry et al.; U.S. Pat. No. 5,254,116 to Baust et al.;
U.S. Pat. No. 5,257,977 to Eshel; U.S. Pat. No. 5,334,181 to
Rubinsky et al.; U.S. Pat. No. 5,400,602 to Chang et al.; U.S. Pat.
No. 5,573,532 to Chang et al.; and U.S. Pat. No. 5,916,212 to Baust
et al., the entire contents of each being hereby incorporated
herein by reference thereto, respectively.
SUMMARY OF THE INVENTION
[0007] The present invention can be embodied in a cryosurgical
system, comprising a container having cryogen within the container;
a pump having a piston submerged within the cryogen; a probe
outside the container for use in cryosurgical procedures; a system
of conduits fluidly interconnecting the piston and the probe
permitting the cryogen to be forced from the piston to the probe
upon activation of the piston; and a pressure relief device fluidly
coupled to the systems of conduits and positioned between the
bellows and the probe.
[0008] The present invention may also be embodied in a pump
assembly for a cryosurgical system, comprising a driving mechanism
coupled to an elongated drive shaft; a bellows coupled to the drive
shaft and adapted to be submersed in cryogen, the bellows formed
from metal; a one-way inlet valve fluidly coupled to the bellows;
and a one-way outlet valve fluidly coupled to the bellows.
[0009] The present invention may also be embodied in a method of
delivering cryogen to a surgical device, comprising providing a
container having cryogen within the container; providing a pump
having a piston within a cylinder and submerged within the cryogen;
providing a surgical instrument outside the container for use in
cryosurgical procedures; providing a system of conduits fluidly
interconnecting the piston and the surgical instrument permitting
the cryogen to be forced from the piston to the probe upon
activation of the piston; providing a pressure relief device
fluidly coupled to the systems of conduits and positioned between
the bellows and the probe; activating the piston to pull cryogen
within the cylinder; activating the piston to push the cryogen from
the cylinder to the surgical instrument at an initial predetermined
pressure.
[0010] Other aspects, features, and advantages of the present
invention will become apparent from the following detailed
description of the illustrated embodiments, the accompanying
drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a system in accordance with an embodiment
of the present invention and includes a cross-sectional view
through a container holding cryogen;
[0012] FIG. 2 is an enlarged, elevational view of the container of
FIG. 1 and its contents;
[0013] FIG. 3 is an enlarged, top view of the assembly within the
container of FIG. 1;
[0014] FIG. 4 is a top view of a valve used in the system
illustrated in FIGS. 1-3;
[0015] FIG. 5 is an elevational view of the valve of FIG. 4;
[0016] FIG. 6 is a schematic view of the system illustrated in FIG.
1 and showing the system as the bellows pulls cryogen within the
cylinder;
[0017] FIG. 7 is a schematic view similar to FIG. 6 but showing the
system as the bellows initially pushes cryogen to the probe;
and
[0018] FIG. 8 is a schematic view similar to FIGS. 6 and 7 but
showing the system as the bellows pushes cryogen to the probe and
with the pressure relief valve activated to control the fluid
pressure.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIGS. 1-8 illustrate a preferred embodiment of a cryogenic
pump, system, and method according to the present invention. The
system 10 provides instantaneous sub-cooling of liquid cryogen 14,
thereby creating a cryogen state characterized by an excess
capacity to absorb heat without boiling. By manipulating the
pressure relationships in the plumbing circuit 26, sub-cooled
liquid 214 is transported to the distal cryoprobe tip 130 in 1-20
seconds allowing near instantaneous freezing at the probe tip 130.
This rate of cooling is faster and the attainable low temperature
is lower than comparable Joule-Thompson-based cryogenic
devices.
[0020] The illustrated system 10 includes a container or dewar 12
containing cryogen 14, such as liquid nitrogen. A support 16 is
positioned within the container 12 and submerged within the cryogen
14. A pump 18 is coupled to the container 12 such that the piston
56, illustrated in the form of a bellows, is also submerged within
the cryogen 14. By way of a conduit system 26, the bellows 56 is
fluidly coupled to an output manifold 20, a pressure release valve
22, and a surgical probe 24. A control system 28 monitors the
temperature of the probe tip 130 and adjusts the system components
as necessary to maintain the desired temperature at probe tip
130.
[0021] The container 12 is of substantially conventional design,
except that it is appropriately adapted to support pump 18. Pump 18
includes a linear drive motor 52 mounted outside the container 12
and, preferably mounted to the top of the container 12. A drive
shaft 54 extends down from the motor 52, through the cryogen 14 and
couples to the bellows 56. The bellows 56 is appropriately
constructed to fit within a cylinder 58. Bellows 56 is preferably
formed from stainless steel. Also, although the figures illustrate
a system 10 with two bellows 56, any appropriate number of bellow
systems may be employed. The cylinder 58 has a one-way inlet valve
60 coupled to an inlet conduit 62, and a one-way outlet valve 64
coupled to an outlet conduit. The cylinder 58 and bellows 56
assembly is rigidly secured to the support 16 along with manifold
20.
[0022] Manifold 20 has an inlet conduit 80 fluidly coupled to the
outlet valves 64 of the bellows 56. Manifold 20 also has outlet
conduits 82 fluidly coupled to the probe 24. Although five outlet
conduits 82 are illustrated it should be understood that the number
of outlet conduits 82 is dependent on the system requirements, and
that more or fewer outlet conduits 82 may be used. The manifold 20
also has an outlet port 84 for coupling with the pressure relief
valve 22.
[0023] Pressure relief valve 22 is preferably mounted outside the
container 12 and is coupled to the manifold by inlet conduit 100.
The valve 22 also has an outlet conduit that leads back into the
cryogen 14 in container 12 to return, to the container 12, the
cryogen 14 that has been released from the conduit system 26 to
lower the pressure as desired.
[0024] The surgical apparatus illustrated is shown as probe 24 with
its corresponding tip 130 and is intended to represent any
appropriate cryosurgical device, including probe tips, such as
those known in the prior art. Examples of prior art probes are
disclosed in the patents incorporated herein as set forth
above.
[0025] Thus, the illustrated embodiment includes a reciprocating
stainless steel bellows pump 18 that operates while submerged in
liquid cryogen 14 and that causes instantaneous sub-cooling of the
liquid cryogen 14 during the compression stroke of the bellows 56,
thereby creating a cryogen state characterized by an excess
capacity to absorb heat without boiling. Further, by manipulating
the pressure relationships in the plumbing circuit 26, sub-cooled
liquid 214 is transported to the distal cryoprobe tip 130 in 1-20
seconds allowing near instantaneous freezing at the probe tip
130.
[0026] In the illustrated embodiment, one or more stainless steel
bellows "pistons" 56 are driven by a surface mounted linear drive
system 52 capable of pressure regulation. The reciprocating action
of each bellows piston 56 a) sequentially produces a negative
pressure to draw in liquid cryogen 14 on the fill stroke through a
one-way check valve 60 and b) sequentially discharge liquid cryogen
214 at a prescribed pressure profile out through a second one-way
check valve 64 to a pressure manifold 20 connected to the probe 24
plumbing circuitry. The preferred, prescribed profile is a range of
between 250 pounds per square inch (psi) and 400 pounds per square
inch (psi).
[0027] The pressure pulse profile establishes an initial high,
transient pressure spike that causes a colligative-based
sub-cooling of the liquid cryogen 14, which establishes a boiling
point differential of approximately 30-40 degrees Celsius, thereby
establishing an excess temperature capacity (the level of
temperature rise that can be allowed before boiling of the cryogen
14) supporting the instantaneous distribution of sub-cooled cryogen
214 in the plumbing circuit 26. Following the transient pressure
spike, pressure is reduced to a base level to sustain the desired
rate of ice growth a the distal end of the circuit, that is, at the
probe 24. Conventional control system technology can be employed in
controlling the interaction between the probe 24 and the pressure
relief valve 22 and/or the pump 18, that is, in producing the
control system 28.
[0028] Pressure relief and control is provided by an appropriately
designed pressure transducer-valve interface 22 outside the
cryogen-containing dewar 12.
[0029] Thus, while the invention has been disclosed and described
with reference with a limited number of embodiments, it will be
apparent that variations and modifications may be made thereto
without departure from the spirit and scope of the invention and
various other modifications may occur to those skilled in the art.
Therefore, the following claims are intended to cover
modifications, variations, and equivalents thereof.
* * * * *