U.S. patent number 6,741,884 [Application Number 09/389,342] was granted by the patent office on 2004-05-25 for infrared endoscopic balloon probes.
This patent grant is currently assigned to HyperMed, Inc.. Invention is credited to Jenny E. Freeman, Michael J. Hopmeier, Charles R. Lambert.
United States Patent |
6,741,884 |
Freeman , et al. |
May 25, 2004 |
Infrared endoscopic balloon probes
Abstract
Balloon probes, adapted for use in endoscopy and other medical
procedures, are useful to obtain spectroscopic information
reflected or emitted from a tissue of interest in the infrared
spectral region. The information collected by the probe is useful
in the diagnosis and treatment of disease. The invention also
relates to methods utilizing these probes to analyze a surface of
interest, in a minimally invasive manner, in connection with the
diagnosis and treatment of disease.
Inventors: |
Freeman; Jenny E. (Chestnut
Hill, MA), Lambert; Charles R. (Melbourne, FL), Hopmeier;
Michael J. (Mary Esther, FL) |
Assignee: |
HyperMed, Inc. (Weston,
MA)
|
Family
ID: |
32314255 |
Appl.
No.: |
09/389,342 |
Filed: |
September 2, 1999 |
Current U.S.
Class: |
600/473; 600/116;
600/178; 600/182 |
Current CPC
Class: |
A61B
5/0086 (20130101); A61B 5/6853 (20130101); A61B
5/6885 (20130101); A61B 5/0075 (20130101) |
Current International
Class: |
A61B
5/00 (20060101); A61B 005/00 () |
Field of
Search: |
;600/473,476,310,478,109,116,160,178,182 ;606/15,16 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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EP |
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0783867 |
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Jul 1997 |
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EP |
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2300045 |
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Oct 1996 |
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GB |
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WO9215008 |
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Sep 1992 |
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WO |
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WO9607889 |
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Mar 1996 |
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WO |
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9620638 |
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Jul 1996 |
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WO |
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Other References
Prahl, S. A. et al, "Determination of optical properties of turbid
media using pulsed photothermal radiometry", Phys. Med. Biol.,
1992, vol. 37, No. 6, 1203-1217, Bristol, UK. .
International Search Report for PCT/US98/22961 dated Jul. 6,
1999..
|
Primary Examiner: Smith; Ruth S.
Attorney, Agent or Firm: Morrison & Foerster LLP
Parent Case Text
REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent
Application Serial No. 60/098,957 filed Sep. 3, 1998.
Claims
We claim:
1. A probe, comprising: one or more infrared transparent fibers,
each fiber comprising: a proximal end; a collection end opposite
the proximal end; and a conductive core which is conductive to
radiation and located between the proximal end and the collection
end; a balloon positioned relative to the one or more fibers and
proximate the collection end of the one or more fibers; a source of
infrared lucent fluid; and a detector responsive to radiation from
the proximal end of the one or more fibers.
2. The probe of claim 1, wherein the balloon is toroidally
shaped.
3. The probe of claim 1, wherein the balloon comprises a thin layer
of material that is infrared lucent when inflated with a nitrogen
gas.
4. The probe of claim 1, wherein the collection end of the one or
more fibers is positioned inside the balloon such that said
collection end presses against a wall of the balloon.
5. The probe of claim 1, wherein the conductive core further
comprises a turn for changing a direction of radiation along said
conductive core wherein the turn comprises a bend, mirror, crystal
or prism.
6. The probe of claim 1, wherein the one or more fibers comprise a
material that is transparent to radiation between 0.8 and 25
microns.
7. The probe of claim 1, further comprising a source of infrared
radiation.
8. The probe of claim 1, further comprising an optical coupler for
optically coupling said one or more infrared transparent fibers to
a spectrometer.
9. The probe of claim 8, wherein the optical coupler comprises a
lens.
10. The probe of claim 1, wherein the one or more infrared
transparent fibers are flexible.
11. The probe of claim 1, further comprising means proximate to
said collection end to orient said collection end in a radial
direction with respect to a longitudinal axis of said conductive
core.
12. The probe of claim 11, where the one or more infrared
transparent fibers are moveably disposed in a sheath and said means
proximate to said collection end comprises a bend in said
conductive core, and wherein said bend deploys radially when said
collection end is advanced through a hole in said sheath.
13. The probe of claim 1, further comprising means for orienting
collection of infrared radiation by the one or more infrared
transparent fibers, said means selected from the group consisting
of a bend, a mirror, and a crystal.
14. The probe of claim 1, further comprising a detector element
functionally coupled to said one or more infrared transparent
fibers to detect infrared radiation from said proximal end of said
one or more infrared transparent fibers, wherein said detector
element is disposed at or near the collection end of the one or
more infrared transparent fibers.
15. The probe of claim 1, wherein the balloon has a diameter of
greater than 1 cm when said balloon is maximally inflated.
16. The probe of claim 1, wherein the balloon has a diameter of
less than 4 mm when said balloon is maximally inflated.
17. The probe of claim 1, wherein the collection end of said one or
more infrared transparent fibers is positioned in direct contact
with a wall of said balloon.
18. The probe of claim 1, wherein the collection end of said one or
more infrared transparent fibers is positioned adjacent to the
outside of a wall of said balloon.
19. A probe comprising: one or more infrared transparent fibers in
the form of a bundle, said bundle comprising: a proximal end; a
distal collection end opposite said proximal end adapted to collect
infrared radiation; and an infrared conductive core located between
said proximal end and said distal collection end; a sheath for
receiving at least a portion of said bundle, wherein said sheath
has a distal portion extending beyond said distal collection end of
said bundle; a first anchoring balloon disposed on said sheath
between said proximal end and said distal collection end of said
bundle; a second anchoring balloon disposed on said distal portion
of said sheath; and a cavity between said first and second
anchoring balloons, wherein said distal collection end is disposed
in said cavity.
20. The probe of claim 19, further comprising an opening in said
sheath between said first and said second anchoring balloons.
21. The probe of claim 19, wherein the first or second anchoring
balloon further comprises a proximate end and a distal end, and a
passage through said balloon to allow fluid communication between
said proximate end and said distal end.
22. The probe of claim 19, further comprising a plurality of
collecting fibers disposable at least partly in said sheath for
collecting infrared radiation.
23. The probe of claim 19, further comprising an interactive
coating on said first or second balloon.
24. The probe of claim 23, wherein the coating is selected from the
group consisting of proteins, antigens, stimulants, effector
molecules and chemicals.
25. The probe of claim 19, further comprising a display wherein
radiation collected by each of said one or more infrared
transparent fibers provides a single pixel for incorporation into
said display.
26. The probe of claim 19, further comprising an image display
wherein radiation collected by the plurality of one or more
infrared transparent fibers is translated into an image on said
image display.
27. The probe of claim 19, wherein the fiber bundle is
flexible.
28. The probe of claim 19, further comprising means proximate to
said distal collection end of at least one of said one or more
fibers to orient said distal collection end in a radial direction
with respect to a longitudinal axis of the conductive core.
29. The probe of claim 28, wherein the means proximate to said
distal collection end to orient said distal collection end in a
radial direction comprises a bend in said conductive core.
30. The probe of claim 29, wherein the bend in said conductive core
orients said plurality of one or more infrared transparent fibers
in at least two different directions.
31. The probe of claim 19, further comprising a detector which
optionally comprises a focal plane detector array.
32. A probe comprising: one or more infrared transparent fibers,
said one or more infrared transparent fibers comprising: a proximal
end; a distal collection end opposite said proximal end for
collection of infrared radiation; and an infrared conductive core
located between said proximal end and said distal collection end; a
sheath for receiving at least a portion of said one or more
infrared transparent fibers; an anchoring and protective balloon
disposed on said sheath, wherein said balloon is infrared lucent
and toroidally shaped, and protects said distal collection end from
infrared contaminants; an illumination fiber having a distal
illumination end adjacent said distal collection end of said one or
more infrared transparent fibers and a proximate end coupled to an
illumination source; and a passage through said balloon to allow
fluid communication between a proximal end and distal end of said
balloon.
33. The probe of claim 32, wherein the sheath surrounds a portion
of said one or more infrared transparent fibers and a portion of
said illumination fiber.
34. A method for obtaining information about a surface of interest
comprising the steps of: positioning a probe adjacent to said
surface of interest, said probe comprising: a collection fiber,
said collection fiber comprising a proximal end, a distal
collection end opposite said proximal end for collection of
infrared radiation; and an infrared conductive core located between
said proximal end and said distal collection end; a first anchoring
balloon disposed therein which is infrared lucent; and a sheath
surrounding a portion of said collection fiber wherein said first
anchoring balloon is disposed on said sheath between said proximal
end and said distal collection end, and said sheath extends
distally past said distal collection end and wherein said probe
further comprises a second anchoring balloon disposed on said
sheath distal to said distal collection end, and wherein said
surface of interest is disposed in a lumen; inflating said first
anchoring balloon and said second anchoring balloon to create an
enclosed volume defined by said first anchoring balloon, said
second anchoring balloon and said lumen; filling said volume with a
fluid; collecting infrared radiation from said surface with said
probe; transmitting infrared radiation collected from said surface
to analyzing means; and analyzing the infrared radiation with said
analyzing means to determine one or more properties of said
surface.
35. The method of claim 34, further comprising the step of
distending the surface of interest by inflating said first
anchoring balloon to optimize analysis of the surface.
36. The method of claim 34, wherein the first and second anchoring
balloons are inflated sequentially.
37. The method of claim 34, wherein the fluid comprises an infrared
lucent gas.
38. The method of claim 34, wherein the fluid comprises an infrared
lucent liquid.
39. The method of claim 34, further comprising the step of
inserting said distal collection end of said collection fiber into
the enclosed volume after inflating said first and second anchoring
balloons and filing the volume with said fluid.
40. A probe comprising: one or more infrared transparent fibers,
each fiber comprising: a proximal end; a collection end opposite
the proximal end; and a conductive core which is conductive to
radiation and located between the proximal end and the collection
end; a balloon with a first opening along its length and a second
opening midway along the length of the first opening, and extending
from the midway point of the first opening to outside the balloon,
and positioned at and covering the collection end wherein the one
or more fibers at the collection end of the probe enter an end of
the first opening of the balloon and exit the second opening to
contact a sample surface adjacent to the balloon surface; a source
of a fluid to expand the balloon; and a detector responsive to
radiation from the proximal end of the one or more fibers.
41. The probe of claim 40, wherein the balloon comprises a thin
layer of material that is infrared lucent when inflated with
atmospheric gas.
42. The probe of claim 40, further comprising a turn for changing
the direction of radiation wherein the turn comprises a bend,
mirror, or crystal.
43. The probe of claim 40, wherein the one or more fibers comprises
a material that is transparent to radiation between 3 and 14
microns.
44. A probe comprising: one or more infrared transparent fibers,
each fiber comprising: a proximal end; a collection end opposite
the proximal end; and a conductive core which is conductive to
radiation and located between the proximal end and the collection
end; a balloon with an opening along its length to allow passage of
body fluids wherein the one or more fibers at the collection end of
the probe is attached to and located at the outer surface of a
portion of the balloon without extending into the balloon; a source
of a fluid to expand the balloon; and a detector responsive to
radiation from the proximal end of the one or more fibers.
45. The probe of claim 44, wherein the balloon is toroidally
shaped.
46. The probe of claim 44, wherein the conductive core further
comprising a turn for changing the direction of radiation along
said core wherein the turn comprises a bend, mirror, crystal or
prism.
47. The probe of claim 44, wherein the one or more fibers comprises
a material that is transparent to radiation between 6 and 12
microns.
48. The probe of claim 44, wherein the balloon comprises an
infrared translucent material.
49. A method for obtaining spectral information from a body surface
inside a lumen of the body using an infrared probe, the probe
comprising: one or more infrared transparent fibers, each fiber
comprising: a proximal end; a collection end opposite the proximal
end; a conductive core which is conductive to radiation and located
between the proximal end and the collection end; and a balloon with
a first opening along its length and a second opening midway along
the length of the first opening, and extending from the midway
point of the first opening to outside the balloon, and positioned
at and covering the collection end, wherein the one or more fibers
at the collection end of the probe enter an end of the first
opening of the balloon and exit the second opening to contact a
sample surface adjacent to the balloon surface, and a fluid to
expand the balloon, comprising: positioning the probe inside the
lumen and adjacent to the body surface; and collecting radiation
from the surface using the probe.
50. The method of claim 49, further comprising the step of
distending the surface by inflating the balloon with the fluid.
51. A method for obtaining spectral information from a body surface
inside a lumen of the body using a probe comprising: one or more
infrared transparent fibers, each fiber including: a proximal end;
a collection end opposite the proximal end; a conductive core which
is conductive to radiation and located between the proximal end and
the collection end; a balloon with an opening along its length to
allow passage of body fluids, wherein the one or more fibers at the
collection end of the probe are attached to and located at the
outer surface of a portion of the balloon without extending into
the balloon; and a source of a fluid to expand the balloon,
comprising: positioning the probe inside the lumen and adjacent to
the body surface; and collecting radiation from the surface using
the probe.
52. The method of claim 51, further comprising the step of
distending the surface by inflating the balloon with the fluid.
Description
BACKGROUND
1. Field of the Invention
The present invention relates to probes useful in endoscopy and
other procedures, and more particularly to balloon probes adapted
to obtain spectroscopic information in the infrared spectral
region. The invention also relates to methods that utilize these
probes to analyze a surface of interest in connection with the
diagnosis and treatment of disease.
2. Description of the Background
Numerous minimally-invasive diagnostic and treatment devices and
methods of using them have been developed. Two such categories of
devices are endoscopes and balloon catheters.
Endoscopes have proved useful in the examination of internal
surfaces, in connection with various surgical and diagnostic
procedures. However, conventional endoscopes, such as colonoscopes,
gastroscopes, bronchoscopes, and angioscopes, are limited in their
ability to detect all pathology present or provide unequivocal
identification of abnormalities. These devices typically collect
reflected visible light from a lumen, which may be expanded with
water or gas, for simple visual evaluation of the tissue surface of
interest. If a definitive diagnosis of the type of pathology or
disease present in the tissue is needed, a tissue specimen is
typically removed or biopsied and submitted for pathologic testing.
Unfortunately, the biopsy process increases the risk of
complications to the patient, such as hemorrhage, infection, and
possible perforation of the organ or vessel under examination.
In addition to endoscopic devices that collect reflected visible
light to produce an image allowing for simple visual evaluation,
endoscopes that detect fluorescence emitted following excitation of
tissue with a radiation source have also been described. One such
device includes a visible light source, an optional endoscopic
probe, optical sensors, a filter, a detector, and a display
monitor. One or two wavelengths of visible light, preferably blue
and red/near-infrared light, is directed to the tissue of interest,
and remittance and autofluorescence is then detected,
integrated/processed and displayed (U.S. Pat. No. 5,590,660 to
MacAulay). This device does not incorporate balloons into the
probes to facilitate optical coupling, to allow infrared-based
evaluation of the diseased tissue.
Another device, useful for diagnosing the condition of GI tissue,
utilizes fiber optics to detect emitted fluorescence following
excitation radiation treatment (U.S. Pat. No. 5,421,337 to
Richards-Kortum). In addition, devices which detect precancerous
lesions using a mercury arc lamp endoscope (U.S. Pat. No. 5,647,368
to Zeng), devices which monitor and determine pre-existing physical
properties of an organ by excitation with UV light (U.S. Pat. No.
5,456,252 to Vari), and devices which determine bilirubin
concentration in tissue using reflectance spectroscopy (U.S. Pat.
No. 5,353,790 to Jacques) have also been described. However, these
devices do not combine balloon endoscopes with infrared radiation
to detect diseased tissue.
Balloon catheters, like endoscopes, have been routinely used for
diagnostics and treatment. Typical uses of conventional balloon
catheters include procedures such as angioplasty and embolectomy.
However, prior to the present invention, these conventional balloon
devices could not be used in procedures in which infrared light is
emitted in close proximity or directly onto a tissue surface,
followed by collection of the light reflected or emitted from the
tissue of interest, due to moisture and fluids in the surrounding
environment.
The use of infrared radiation in catheters and endoscopic devices
is complicated by the fact that water and most bodily fluids are
opaque to infrared light. Consequently, even the slightest amount
of moisture on the collection end of an endoscopic probe impairs
the collection of infrared light. As a result, conventional
endoscopes and balloon catheters cannot be used in infrared
procedures where moisture or bodily fluids are present.
Fiber optic laser catheters and endoscopes having a protective
shield over the probe tip have been described as useful in
connection with the diagnosis and removal of atherosclerosis. In
one such device, an optical fiber(s) carrying laser radiation is
mounted in a catheter having a transparent protective optical
shield over its distal end (U.S. Pat. Nos. 5,318,024 and 5,125,404
to Kittrell). The fiber(s) is anchored within the catheter so that
there is an appropriate distance or space between the output end of
the fiber(s) and the tip of the shield. The intervening space may
be filled with fluid, optical surfaces may be optically contacted,
or they may be anti-reflection coated to reduce reflections and
maximize transmitted light. The catheter may be inserted into a
blood vessel and the shield brought into contact with a plaque or
obstruction site.
In this device, the protective optical shield mechanically
displaces blood at the region to be analyzed and also protects the
distal tip of the optical fiber(s) from intra-arterial contents. By
locally displacing blood, the shield allows viewing of the tissue
of interest without the need for a purge or flush. The optical
shield may be in the form of glass, fused silica, sapphire or other
optically transparent material. A flexible balloon over the tip of
the probe may also be used as an optical shield. A different
balloon may be used to provide an anchor point for positioning the
catheter during use.
Although the shields of these devices protect a probe tip from
blood contaminants, the use of a single balloon to both anchor and
protect the tip of the probe from infrared opaque contaminants,
which simultaneously allows optical coupling in the infrared region
between the probe tip and the tissue surface has not previously
been described. The Kittrel devices are designed for use with
visible light. In addition, probes incorporating two anchoring
balloons which allow the evacuation of a lumen and its subsequent
filling with an infrared lucent coupling fluid are also not
described.
As can be seen, because of the challenges posed by the effect of
moisture on infrared light transmission, available endoscopic
devices and catheters are limited in their ability to access and
evaluate tissue and/or the lumen of vessels and organs using
infrared light. There is therefore a need for a relatively
non-invasive device which allows for optical coupling of a probe to
the tissue or surface of interest, thereby allowing thorough
evaluation and diagnosis of tissues and/or the lumen of vessels and
organs using infrared radiation.
SUMMARY OF THE INVENTION
The invention overcomes the problems and disadvantages associated
with current strategies and designs and provides new devices and
methods for obtaining diagnostic information through the use of
endoscopic balloon probes, particularly those utilizing infrared
(IR) spectroscopy.
Probes according to a preferred embodiment of the present invention
include an IR-transmitting single or multiple fiber endoscope,
which is connected to a high resolution spectrometer. Infrared
spectra are collected and used for diagnosis. The use of
spectroscopy with a fiberoptic endoscope allows the collection of
high resolution information in the infrared spectral region from
diseased tissue. The present invention allows for rapid and
accurate analysis of an organ, despite the presence of moisture,
without the need for a tissue biopsy and its potential
complications, such as hemorrhage, perforation and infection. In
addition, by using the anchoring balloons in conjunction with the
endoscopic probes, collection of diagnostic spectra, particularly
infrared radiation, in the lumen of a vessel or organ is even
further enhanced. The novel balloon configurations displace any
opaque fluids which may be present and allow optical coupling of
the probe to the tissue of interest.
In addition, multiple fibers may be paired with hyperspectral
imaging techniques. Each fiber's data may be processed to provide a
single pixel. The pixels produced by each individual fiber may be
incorporated into an imaging array and/or translated into an image
or other display optimized so that it may be readily interpreted or
read by the user.
Accordingly, one embodiment of the invention is directed to a probe
device which is useful for collecting infrared radiation from a
surface of interest. The collected radiation is analyzed to provide
information about the tissue surface. The probe device of this
embodiment comprises a collection fiber which has a proximal end, a
distal collection end opposite the proximal end adapted to collect
infrared radiation, and an infrared conductive core located between
the proximal end and the distal collection end. A sheath surrounds
a portion of the collection fiber. A first anchoring balloon is
preferably disposed on the sheath. The distal collection end of the
collection fiber may be nested inside or disposed inside the
balloon. This configuration displaces the opaque fluids which may
be present, optically couples the probe to the tissue when the
balloon is inflated, and protects the collection end of the probe
from contamination.
Alternately, the first anchoring balloon may be disposed on the
sheath between the proximal end and the distal collection end of
the fiber and a second anchoring balloon may be disposed on a
portion of the sheath that extends distally past the distal
collection end of the collection fiber. When the two balloons are
inflated, the void created between the balloons and the lumen wall
may be filled with an infrared lucent fluid, displacing any
infrared opaque fluids. This allows optical coupling of the
collection end of the probe to the tissue surface, and protects the
end of the probe from contamination.
Another embodiment is directed to a probe device having a plurality
of collection fibers adapted to collect light, which is preferably
infrared light. The probe device of this embodiment comprises an
imaging collection fiber bundle comprising a plurality of
collection fibers, each of the plurality of collection fibers
comprising a proximal end, a distal collection end opposite the
proximal end, and a conductive core located between the proximal
end and the distal collection end. A first anchoring balloon is
disposed on the fiber bundle; preferably it is disposed so that the
distal collection ends of the plurality of collection fibers are
disposed inside the balloon. Alternately, it may have the two
balloon configuration previously described.
Another embodiment is directed to an endoscopic probe having a
collection fiber which has a proximal end, a distal collection end
opposite the proximal end adapted to collect infrared light, and a
conductive core located between the proximal end and the collection
end. The probe also has an illumination fiber having a distal
illumination end adjacent the distal collection end of the
collection fiber, and a proximate end coupled to the illumination
source. An infrared lucent anchoring balloon is positioned on the
probe such that the distal collection end of the collection fiber
and the illumination end of the illumination fiber is disposed in
the balloon. The illumination fiber preferably provides infrared
light.
Another embodiment of the invention is directed to an endoscopic
probe comprising a toroidally-shaped anchoring balloon, having a
central hole or bore therethrough, and a collection fiber adapted
to collect infrared radiation. The fiber has a distal collection
end disposed inside the central hole of the balloon.
The present invention is also directed to methods for obtaining
information about a surface of interest. One such method comprises
the steps of positioning a probe adjacent to the surface of
interest, collecting infrared light using the probe, transmitting
the infrared light from the surface to analyzing means, and
analyzing the infrared light to determine one or more properties of
the surface. In this embodiment, the probe preferably comprises a
collection fiber, the collection fiber comprising a proximal end, a
distal collection end opposite the proximal end adapted to collect
infrared light, and an infrared conductive core located between the
proximal end and the distal collection end, and at least one
anchoring balloon disposed on the probe.
Another embodiment is directed to a method for obtaining
information about a surface of interest, comprising the steps of
positioning a probe adjacent to the surface of interest, collecting
infrared light using the probe, transmitting the infrared light
from the surface to analyzing means, and analyzing the light to
determine one or more properties of the surface. In this
embodiment, the probe preferably comprises a light collection fiber
bundle comprising a plurality of collection fibers adapted to
collect infrared light, each of the plurality of collection fibers
having a proximal end, a distal collection end opposite the
proximal end, and a conductive core located between the proximal
end and the distal collection end. A first balloon may be
positioned on a sheath between the proximal end and the collection
end of the plurality of collection fibers and a second balloon
disposed on the sheath distal to the collection ends. Alternately,
a balloon may be disposed on the probe such that the distal
collection ends of the fibers lie inside the balloon.
Still another embodiment is directed to a method for obtaining
information about a tissue surface, comprising the steps of
collecting infrared radiation from the tissue surface using a probe
placed proximate to the tissue surface, the probe having a
longitudinal axis, transmitting the infrared radiation from the
tissue surface to a remote analyzer, and analyzing the infrared
information to determine properties of the tissue. The remote
analyzer may comprise a spectrometer and detector array.
Although preferred embodiments of the invention are directed to
probes having fibers and optical coupling means uniquely suited for
the collection and analysis of infrared wavelengths, as will be
clear to those of skill in the art, in other embodiments,
additional fibers may be incorporated into the probes, so that
other wavelengths (in addition to infrared) may be collected and
analyzed.
Other objects and advantages of the invention are set forth in part
in the description which follows, and in part, will be obvious from
this description, or may be learned from the practice of the
invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 Longitudinal cross-section of a probe device according to a
first embodiment of the present invention, showing an illumination
fiber in phantom.
FIG. 2 Longitudinal cross-section of a probe device according to a
second embodiment of the present invention, showing a multi-fiber
configuration in phantom.
FIG. 3 Longitudinal cross-section of a probe device according to a
third embodiment of the present invention.
FIG. 4 Longitudinal cross-section of a probe device according to a
fourth embodiment of the present invention.
DESCRIPTION OF THE INVENTION
As embodied and broadly described herein, the present invention is
directed to probe devices useful in a wide variety of medical and
other procedures, including, but not limited to, endoscopic
procedures such as thoracoscopy, laparoscopy, angioscopy and
biopsy. Specifically, the present invention relates to balloon
probes adapted to obtain spectroscopic information in a desirable
spectral range, such as in the infrared spectral region. The
invention also relates to methods that utilize these probes to
analyze a surface of interest, such as in connection with the
diagnosis and treatment of disease.
The present invention overcomes the problems inherent in the use of
infrared radiation in a moist environment by providing novel means
for bringing the collection end of the optic fiber into
unobstructed optical contact with the tissue surface. The novel
balloon configurations prevent interference with infrared
excitation and collection due to moisture, which has made the use
of infrared radiation in conventional scopes impossible.
Probes according to the present invention are advantageous in that
they may be used to detect the composition or other qualities of a
tissue surface in a non-invasive manner. For example, by detecting
the frequencies and intensities of infrared light reflected or
emitted from the wall, information about chemical bond energies can
be obtained in a non-invasive manner. This bond energy information
can then be translated into information about the composition of
the wall and used as a diagnostic aid.
The probe devices and methods of the present invention can be used
to determine tissue viability (i.e., whether tissue is dead or
living, and whether it is predicted to remain living), detecting
tissue ischemia (e.g., in heart, or in leg after a gunshot wound),
differentiating between normal and malignant cells and tissues
(e.g., delineating tumors, dysplasias and precancerous tissue,
detecting metastasis), differentiating between infected and normal
(but inflamed) tissue (e.g., extent of aortic root infection),
quantification and identification of pathogens, and differentiating
and delineating other pathologic states. Applications further
include evaluation of tissue and blood chemistry, as well as
examining the chemistry of blood vessel walls, including lipid and
plaque characteristics and determining effects of lipid-lowering
agents.
The probes and apparatus of the present invention may also be
applied by veterinarians to animals, by dentists to dental
applications, such as periodontal disease, and by pathologists in
connection with forensic evaluation of a tissue of interest.
In addition, instruments according to the invention permit a
surgeon or a physician to diagnose a medical condition or develop a
surgical strategy based on real-time spectroscopic information
obtained during surgery or in the course of performing clinical
procedures or other medical evaluations. As a result, the physician
is able to readily obtain significantly more information about a
patient's condition than he or she might otherwise have been able
to obtain. This additional information may permit a given surgical
procedure to be carried out more efficiently, leading lead to more
successful surgical results.
The general-purpose nature of instruments according to the present
invention can help a surgeon develop significant amounts of medical
information in time-critical surgical situations. For example, a
patient may undergo surgery during which the surgeon may wish to
evaluate a tumor, an area of blood vessel abnormality, or another
pathological condition. Using the present invention, the physician
can quickly determine the nature and extent of the pathology while
the patient is still under anesthesia. This is particularly
beneficial during major surgery, where significantly extending
surgery duration increases morbidity and mortality risk. Because
the devices of the present invention allow for rapid and minimally
invasive procedures, the patient's overall risk is reduced. The
immediate diagnosis and evaluation possible using the devices of
the present invention provide significant benefits to the
patient.
A preferred embodiment of one probe device according to the present
invention is depicted in FIG. 1. In the figures, like reference
numerals refer to like features or elements so that a further
description thereof is omitted. Referring to FIG. 1, probe or probe
device 10 includes a sheath 12, an optical fiber 14, and a balloon
16. Balloon 16 has a wall 17. Sheath 12 is a flexible hollow tube
that allows optical fiber 14 of probe 10 to be threaded along a
guide wire inserted by a physician, although rigid or semi-rigid
probes that do not require a guiding mechanism may also be used. A
needle or other suitable means may also be used to guide the probe
into place.
Suitable optical fibers useful in the present invention include,
but are not limited to infrared fibers, such as fluoride-based
glasses, chalcogenide glass fibers, sulfide-based fibers and
telluride-based fibers. In a preferred embodiment, fluoride-based
glass fibers are used. In another embodiment, chalcogenide glass
fibers with low optical loss in the 2-11 .mu.m wavelength region
are used. Another embodiment of the invention may incorporate
sulfide-based fibers, which transmit in the 1-6 .mu.m region.
Alternately, another embodiment may use telluride-based fibers
which transmit in the 2-11 .mu.m region. In yet another embodiment,
mixtures of fibers may be used. Current minimal optical loss for
glass cladded sulfide fibers is 0.4 dB/m at 2.6 .mu.m. The minimal
optical loss for telluride fibers is 0.7 dB/m at 6.6 .mu.m. An
anti-reflection (AR) coating may be applied to fiber end faces to
increase transmission.
Optical fiber 14 includes a distal optical collection end 20 and a
proximal optical end 26, and may include a bend 22. Distal
collection end 20 is responsive to a surface of tissue of a
patient. Bend 22 is preferably disposed proximate to collection end
20, between collection end 20 and proximal optical end 26. Proximal
optical end 20 is optically coupled to spectrometer 32, such as by
lens 28. Spectrometer 32 is coupled to optical detector 30.
Spectrometer 32 is used to select one or more desired wavelengths
which are transmitted to an optical detector 30 for
measurement.
In the embodiment of FIG. 1, balloon 16 may be a standard
angioplasty balloon designed for application to blood vessels.
However, balloons of other sizes and shapes may also be employed
depending on the intended application. Preferably, the balloon is
infrared lucent or virtually infrared lucent when inflated. For
example, teflon may be used to make a suitable balloon. By making
the balloon very thin when inflated, any minor opacity to infrared
light may be digitally subtracted from the signal using known
techniques.
As shown in FIG. 1, when inserted, collection end 20 of the optical
fiber 14 is disposed inside the lumen of balloon 16. Collection end
20 may directly contact the balloon wall. Alternately, there may be
a gap between collection end 20 and the balloon wall 17 when the
balloon is inflated.
In operation, probe 10 is inserted into an opening, such as an
orifice or incision in a patient, and it is threaded until
collection end 20 of the fiber is positioned (inside balloon 16)
proximate or adjacent to the exposed tissue surface of interest.
Balloon 16 is then inflated, such as via an inflation channel in
sheath 12 with an infrared lucent gas or liquid. A preferred
infrared lucent fluid is dry nitrogen gas. However, the media or
medium chosen may be determined by the specific purpose and
location of the procedure. Following inflation, collection end 20
is brought into close proximity or is optically coupled to the
exposed tissue wall or surface of interest 18.
The optical coupling provided by the balloons of the invention
allows the collection end of the probe to emit and collect infrared
light unimpeded by infrared opaque fluids, such as water, blood or
other bodily fluids. For example, the surface may be a lumen wall
such as the wall of a blood vessel, the lining of an intestine, a
chamber of the heart (e.g., to look for signs of rejection), or
other appropriate lumen wall in the patient. The surface to be
examined can also be created by an incision, such as an incision in
the breast. The probes of the present invention may be used in
procedures examining body cavities or any type of lumen, including
fetoscopic and laparoscopic procedures.
Bend 22 in the fiber permits collection end 20 to collect light
from a radial direction with respect to the longitudinal axis of
the core of fiber 14. In radial-looking embodiments, a mirror or
prism may optionally be used to collect light at an angle to the
longitudinal axis of the fiber core. Alternately, a fiber with a
straight end may be used to collect light from a direction aligned
with the longitudinal axis of the fiber.
By inflating the balloon with an infrared lucent fluid, collection
end 20 of fiber 14 is optically coupled to the tissue surface 18.
Light, including, but not limited to, infrared radiation emitted
from or reflected by the wall, is thus transmitted along fiber 14
to the spectrometer and detector by total internal reflection
(TIR). In a preferred embodiment, detector 30 is sensitive in the
infrared spectral regions, allowing spectrometer 32 to present an
infrared image or spectrum to the surgeon. Detector 30 is
preferably sensitive to wavelengths of at least 800-25,000
nanometers (nm) and more preferably, to wavelengths ranging from
3,000-14,000 nm, and most preferably, to wavelengths of
6,000-12,000 nm. The acquired spectrum may be presented directly to
a physician or it may be analyzed by a computer to assist in
identifying attributes of the tissue surface.
The light received by collection end 20 of fiber 14 may be supplied
to the area of interest from source 34 through illumination fiber
36. Illumination fiber 36 has a proximate end 39 optically coupled
to light source 34, and a distal illumination end 41 adjacent to
collection end 20. The light may also be emitted from within the
tissue surface itself (e.g., bioluminescence), or it may be
transmitted through the tissue surface from the other side of the
tissue surface. By using fibers which are transparent in the
ultraviolet region, further spectral information, including
information attributable to fluorescence, may be obtained.
Optionally, as will be clear to those of skill in the art, a single
fiber may be used to both illuminate and collect, for example, by
using a beam splitter to allow both excitation and collection with
a single fiber.
Spectrometers useful in the present invention include dispersive,
fixed or tunable bandpass devices. Preferred spectrometers include
Fourier transform interferometers or dispersive monochromators.
Useful imaging spectrometers include dielectric bandpass filters
and liquid crystal tunable filters (LCTFs). The spectrometer and
detector may be incorporated into a single device. Preferred
illumination sources include infrared ceramic sources, such as a
globar, or tunable infrared lasers. Other illumination sources
include quartz tungsten halogen (QTH) bulbs (near infrared) and
broad band visible bulbs.
FIG. 2 depicts a second embodiment of the present invention.
Referring to FIG. 2, second probe device or probe 40 includes
sheath 42, optical fiber 44, proximate balloon 46 and distal
balloon 48. Optical fiber 44 includes distal optical collection end
50, proximal optical end 56, and bend 52 disposed proximate to
collection end 50. Probe 40 may differ from probe 10 in that the
collection end 50 is not in apposition with or disposed inside the
balloon, but instead sits between the distal and proximate
balloons. The collection ends of probe 40 may or may not be in
apposition with tissue surface 18. Sheath or conduit 42 also
includes opening 65 which connects or allows communication between
the inside of sheath 42 with volume 64. Volume 64 is defined by
proximate balloon 46, distal balloon 48, and tissue surface 18.
Proximal optical end 56 of fiber 44 is functionally coupled to
detector 58, such as a detector array, via a spectrometer.
Probe 40, like probe 10 of the first embodiment, may be implemented
as a single-fiber or multi-fiber probe by providing one or more
additional fibers 54 that run next to first fiber 44 in a bundle.
Fibers 54 may each include a bend 62 in a different plane causing
fibers 54 to diverge radially from first fiber 44 and from each
other. Alternately, the fibers may have axially offset bends 62 in
the same plane. Each of the fibers 54 has a distal collecting end
60 and a proximate end 66, which may be coupled to an additional
detector 68 via a spectrometer. The first detector 58 and the
additional detector(s) 68 may form part of a detector array, such
as a focal plane array (FPA). Alternately, the multiple fibers in
this embodiment may be serviced by a single detector and an optical
multiplexer.
In operation, probe 40 is positioned in the area of interest, and
distal and proximate balloons 46 and 48 are inflated. This creates
cavity or enclosed volume 64 between the two balloons 46 and 48 and
lumen wall 18. In a lumen where there is fluid flow, such as a
blood vessel, the upstream balloon is preferably inflated first.
With both balloons inflated and in place, an infrared transparent
coupling fluid (i.e., a gas or liquid) may be introduced into the
cavity 64 via opening 65 in sheath 42. This optically couples the
collection end 50 or ends 50, 60 to surface 18 of the lumen wall.
Radiation received at each fiber can then be transmitted to its
respective detector 58, 68, and the signals received by the
different detectors can be displayed, such as a linear
circumferential image of the lumen wall 18, or otherwise
processed.
FIG. 3 depicts a third embodiment of the present invention.
Referring to FIG. 3, probe or probe device 70 includes sheath 72,
balloon 76 and fiber 74. Fiber 74 has a distal collection end 77
and a proximal end 79. In this embodiment, the fiber or fibers may
be, but need not be, fixed to an outer surface 73 of balloon 76.
Probe 70 may further include a bend 75, or a reflector that
redirects light from collection end 77 into the fiber 74. The fiber
or fibers may be introduced separately from the balloon using a
guidewire. Apposition to the wall may be accomplished by simple
inflation of balloon 76.
Although probes 10, 40 and 70 are occlusive, probes 10 and 70 may
employ an autoperfusion balloon to allow antegrade blood flow
during inflation. The balloon may be toroidally shaped. The balloon
may have a passage 78 that is either centrally located or offset
from the center. For example, as depicted in FIG. 3, passage 78
allows fluid communication between proximate end 71a and distal end
71b of balloon 70. Probe 40 is less conducive to the addition of a
passage, although a rigid sheath section may be provided that
begins at the distal end of the distal balloon and ends at the
proximate end of the proximal balloon.
FIG. 4 depicts a fourth embodiment of the present invention.
Referring to FIG. 4, probe or probe device 80, which may be used as
an angioscope, includes collection fiber 84, illumination fiber 86,
and sheath 82. The two fibers 84 and 86 are arranged generally in
parallel. Collection fiber 84 has a collection end 90, a bend 92,
and a proximal end 96. Illumination fiber 86 has a distal end 100,
a bend 102 and a proximate end 106. The two fibers are also
surrounded by a flexible sheath 82 that is preferably smaller than
the diameter of the lumen of interest, and includes a bend 112 that
generally follows bends 82 and 92 in the two fibers. Like the other
embodiments, probe 80 may include more than one collection fiber.
In a preferred embodiment, probe 80 does not occupy the entire
diameter of the lumen of interest, and therefore allows fluids such
as blood to pass through the lumen while the assessment is being
made. Alternately, this embodiment may be designed with an
occlusion balloon or balloons and a perfusion lumen.
The embodiments described above preferably employ bends to orient
the collection ends of the fibers, causing the light to be
redirected by total internal reflection. However, any other
suitable means for orienting the collection ends may be substituted
for these bends. For example, in addition to bends, the means for
orienting the collection of light may include mirrors, prisms or
crystals to orient light collection by the fibers. Different
coupling methods may also be employed to couple the light to the
tissue surface and to couple light from the tissue surface into the
fiber, such as lenses, prisms, or waveguides. For example, in one
embodiment, an assembly made up of a looped fiber with a crystal
tip at a bend in the loop is used to acquire light energy.
In various embodiments of the invention described herein which
incorporate bends in the fibers, the probe may be inserted without
the fiber or with the fiber retracted so that the area of the fiber
with the bend lies within the sheath or analogous structure. After
the probe is in position, the fiber may then be advanced out of the
sheath (i.e., through a hole in the wall or an opening in the end
of the sheath), causing the bend to deploy radially. For example,
in one embodiment, a probe may comprise a collection fiber having
an intrinsic bend. The fiber is moveably disposed in a sheath, such
that the bend deploys as the distal end of the fiber is advanced
through a hole in the sheath.
As will be clear to those of skill in the art, in the embodiment of
FIG. 1, the balloon and fluid in the balloon function as part of
the total optic system. The balloon is made so that it is
preferably infrared lucent when inflated with infrared lucent
fluid. As such, the illumination and collection of infrared light
is virtually unimpeded. The balloons in the embodiments of both
FIGS. 1 and 2 also function in preventing fouling of the optic
fiber(s).
Balloons of the present invention may have a coating on their
exterior surface that contacts the tissue of interest and interacts
with said tissue. The balloon coating may comprise agents such as,
for example, proteins, antigens, tissue stimulants, effector
molecules and chemicals. The effect of contacting the tissue of
interest with the balloon coating can then be analyzed according to
the methods of the invention. The use of a coated balloon allows
for a defined area to be impacted. Balloons of the present
invention may also be useful in actively exciting or affecting a
tissue of interest through effects such as changing the temperature
of the tissue, or by distending, stretching or otherwise
mechanically interacting with the tissue. By stretching or
distending tissue, examination of tissue can be further
optimized.
Preferably, the probes of the present invention are adapted to
collect and analyze infrared light and preferably process images
from image planes acquired at wavelengths in the infrared region.
Optionally, the probe devices, including their detectors, may be
sensitive to and capable of detecting and analyzing other spectra
of light. For example, probes may alternately or additionally be
sensitive to the visible and/or near infrared regions. The devices
may operate in multispectral, and hyperspectral, or even
ultraspectral imaging modes.
Multispectral modes involve image processing derived from a
relatively small number of spectral image planes (two wavelengths
to about twenty wavelengths). Hyperspectral and ultra spectral
imaging modes involve at least twenty image planes and can produce
significantly more accurate and informative results. Ultraspectral
modes involve hundreds of wavelengths, and may be able to produce
even further information about the surface under analysis.
Hyperspectral imaging may include selecting specific wavelength
bands for discrimination of a particular diseased state, or it may
also allow the instrument to scan for multiple conditions at the
same time.
The probe devices of the present invention, which are designed to
collect and analyze specific wavelengths, have a number of
potential applications. For example, wavelengths of about 550 and
wavelengths of about 575 associated with oxy- and deoxy-hemoglobin
may be collected and evaluated to determine blood oxygenation. The
relationship between these wavelengths is described in "Hemoglobin:
Molecular Genetics and Clinical Aspects," by H. Franklin Bunn and
Bernard Forget, W. B. Sanders, 1986. Another example would involve
the collection and analysis of the Fourier transform infra-red
spectra of the colon and rectum as described in "Human Colorectal
Cancers Display Abnormal Fourier Transform Spectra," by Basil Rigas
et al., Proceedings of the National Academy of Science, pp.
8140-8144, 1987. As will be clear to those of skill in the art, the
probe devices of the present invention may be designed to collect
and analyze other wavelengths, depending on the intended
application.
One embodiment of the present invention is directed to a probe
device adapted to collect and analyze infrared radiation. The probe
device comprises a collection fiber, the collection fiber
comprising a proximal end, a distal collection end opposite the
proximal end adapted to collect infrared radiation, and an infrared
conductive core located between the proximal end and the collection
end. Preferably, the fiber is flexible. A sheath surrounds a
portion of the collection fiber, and a first anchoring balloon is
disposed on the sheath. The probe device may further comprise a
spectrometer optically coupled to the proximal end of the
collection fiber and a detector, such as a detector array,
functionally coupled to the spectrometer, to detect infrared
radiation from the proximal end of the collection fiber. For
example, a detector such as a mercury cadmium telluride (MCT)
detector may be optically coupled to the spectrometer. Alternately,
if the light is predispersed (i.e., the spectrometer is on the
source rather than the detector), a detector element functionally
coupled to the proximal end of the collection fiber may be disposed
at or near the collection end of the collection fiber, and may even
contact the surface of interest.
The instrument may further include a processing circuit
functionally connected to the radiation detector. The processing
circuit is preferably operative to translate the level of detected
radiation into a measurable signal that is indicative of the level
of damage or disease in the tissue. The signal may be directly
evaluated, or it may be compared to stored reference profiles, to
provide an indication of changes from previous levels or trends in
the patient's health or disease state.
The probe preferably has an illumination fiber which has a distal
illumination end adjacent or in close proximity to the distal
collection end of the collection fiber and a proximate end
optically coupled to an illumination source. Preferably, the
illumination fiber is an infrared transmitting fiber, and the
illumination source is an infrared source such as a globar. The
sheath preferably surrounds a portion of both the collection fiber
and the illumination fiber. Alternately, the collection fiber may
comprise a beam splitter, which allows both excitation and
collection of infrared light by a single collection fiber.
Rather than the use of an illumination fiber and remote
illumination source, the probes of the present invention may
alternately comprise a light source attached at the end of the
probe or otherwise contained within the balloon. The balloon may
also serve as an optical filter for both the illumination light as
well as the collected light. Alternately, a light source may be
provided from a separate source located on one side of the tissue
of interest, while the probe is located on the other side of the
tissue. In this embodiment, the probe and the light source
effectively create a sandwich, with the tissue of interest in the
middle, thereby allowing transmitted light to be collected by the
probe. This sandwich embodiment also allows for volumetric analyses
to be carried out on the tissue, in addition to surface
assessment.
An optical coupler, such as a curved or focusing mirror or a lens
may be used to optically couple the proximal end of the collection
fiber to the spectrometer. The spectrometer is used to select one
or more wavelengths which are transmitted to a detector, such as a
detector array.
The collection end of the fiber is preferably adapted to collect
light radiating or reflecting in a radial direction with respect to
the longitudinal axis of the fiber. To accomplish this, the probe
device preferably includes means proximate the collection end to
orient the collection end in a radial direction with respect to a
longitudinal axis of the fiber core. This may be accomplished, for
example, by a bend in the fiber core. Other means for orienting the
collection of infrared light by the fiber, in addition to bends,
include mirrors, prisms and crystals.
An advantage of the present invention is the ability to obtain
information in a lumen or other area where space is restricted. In
one embodiment, the total diameter of the collection fiber, sheath
and balloon are small enough to permit them to be inserted into
mammalian blood vessels. For example, the total diameter of the
collection fiber, sheath and balloon may have a diameter of less
than 4 mm, and more preferably, less than 2 mm when the first
balloon is maximally inflated. Alternately, the balloons may be
designed so that they can be used in the lumen of a larger organ,
such as intestine. For example, the balloon or balloons may have a
diameter greater than 1-5 cm.
The collection fiber may be disposed in a variety of ways with
respect to the first balloon. For example, in one embodiment, the
collection fiber penetrates the wall of the balloon between the
collection end and the proximal end such that the distal collection
end lies inside the balloon. Alternately, the collection end of the
collection fiber may be positioned adjacent to the outside of the
wall of the balloon. A plurality of collecting fibers may be
disposed in the sheath and used to collect radiation. In
embodiments involving multiple collecting fibers, the fibers may
surround the balloon, or the collection ends may be disposed inside
the balloon. In embodiments where the collection end or ends lie
inside the balloon, the balloon and the liquid or gas used to
inflate the balloon are preferably infrared lucent.
The probe device may alternately include a second anchoring balloon
disposed on a portion of the sheath that extends distally past the
collection end of the collection fiber (i.e., it extends in a
direction opposite the proximal end of the probe device). In this
embodiment, the first balloon is disposed on the sheath between the
proximal end and the collection end of the collection fiber and the
second balloon is disposed on the distal portion of the sheath. An
opening may be disposed in the sheath between the first and the
second balloons. When this probe device is disposed in a lumen, the
balloons may be inflated, and a fluid, preferably an infrared
transparent or lucent fluid, is infused through the opening in the
sheath to fill the void defined by the first and second balloons
and the wall of the lumen.
As noted, it may be desirable to allow fluid flow past the probe
device. In such instances, for example, those with a single
balloon, a passage may be provided through the balloon to allow
fluid communication between the proximate end and the distal end of
the balloon.
Another embodiment of the present invention is directed to a probe
device having an imaging collection fiber bundle comprising a
plurality of collection fibers, each of the plurality of collection
fibers comprising a proximal end, a distal collection end opposite
the proximal end, and a conductive core located between the
proximal end and the collection end. A first anchoring balloon is
disposed on the fiber bundle. The probe device may further comprise
a spectrometer and a detector, such as a detector array, responsive
to the proximal end of the plurality of collection fibers to
acquire an image. The collection fibers preferably conduct infrared
light, but other fibers may be used which conduct other wavelengths
of light such as visible, UV and/or near infrared light. As with
the previous embodiment, the probe device may include an
illumination fiber having a distal illumination end adjacent the
collection ends of the collecting fibers.
In one embodiment of a multi-fiber probe, there may be a central
illumination fiber surrounded by multiple collection fibers. For
example, six collection fibers (or any desired number) may be
placed circumferentially around a center illumination fiber in a
hexagonal configuration, and may be oriented to efficiently collect
the light. In another embodiment, a multi-fiber probe may comprise
a plurality of collection fibers and a plurality of illumination or
excitation fibers; in this embodiment each of the collection fibers
may be associated with or disposed adjacent to its respective
excitation fiber.
With respect to multi-fiber embodiments, the light or data
collected by each fiber may provide a single pixel of information
for incorporation into an image or other display. The image is
preferably optimized to facilitate interpretation. For example, a
two dimensional planar image may be produced from circumferential
data.
A novel feature of balloon probes according to various embodiments
of the invention relates to the incorporation of the balloon into
the actual optical path. For example, in one embodiment, the distal
collection ends are disposed inside the wall of the balloon. This
balloon is made of an infrared lucent material (or is virtually
infrared lucent due to its thickness when inflated) and filled with
an infrared lucent fluid to form a part of the optical path in a
single fiber probe. In multiple fiber probes, this balloon may be
compartmentalized. In the latter embodiment, the balloon may be
partitioned into a plurality of different or separate sacs or
compartments. The collection ends of the collection fibers are each
disposed in a separate compartment.
In multi-fiber embodiments incorporating two anchoring balloons,
the first balloon may be disposed between the proximal and distal
collection ends of the collection fibers. Further, a conduit may be
provided, which passes through a first anchoring balloon, and has a
portion which extends distally past the distal collection end of
the plurality of collection fibers. This embodiment has a second
anchoring balloon attached to the portion of the conduit that
extends distally past the distal collection end of the plurality of
collection fibers. An opening may be provided in the conduit
between the first and second balloons allowing fluid communication
with the space between the first and second balloons.
With respect to single balloon embodiments, the plurality of
collection fibers in the fiber bundle may be positioned adjacent to
the outside of the wall of the balloon, and may form a bundle that
surrounds the balloon. Alternately, the distal collection ends of
the plurality of fibers may be disposed inside the wall of the
balloon, and the balloon may serve as part of the coupler and
collection device. In this embodiment, the collection ends are
preferably close to or contact the balloon wall in operation. The
balloon may be partitioned into a plurality of separate
compartments with the collection ends each disposed in a separate
compartment.
The fiber bundle may be flexible, and may include means proximate
the collection end of each fiber to orient the collection ends in a
radial direction with respect to the axis of the core of the
fibers, such as bends in the fiber cores. Mirrors, prisms and
crystals may also be used as a means for orienting collection of
light. In a preferred embodiment, the bends in the fiber cores
orient the plurality of collection fibers in at least two different
directions.
In this embodiment, the detector may comprise a focal plane array
such as a mercury cadmium telluride plane array or a microbolometer
array. The device may further comprise an optical multiplexer such
as a digital micro mirror array.
Instruments according to the present invention may also include
imaging optic means within the probe, a spectral separator
optically responsive to the imaging optic means, and an imaging
sensor optically responsive to the spectral separator. The spectral
separator may be a tunable filter and the imaging sensor may be a
two-dimensional imaging array, such as a focal plane array. The
instrument may optionally comprise a diagnostic processor having an
image acquisition interface responsive to the imaging sensor. The
diagnostic processor may also have a filter control interface to
which the spectral separator is responsive.
The diagnostic processor may also include a general-purpose
processing module and diagnostic protocol modules, which may each
include filter transfer functions and an image processing protocol.
The general-purpose processing module may be operative to instruct
the filter to successively apply the filter transfer functions to
light collected from the patient, to acquire from the imaging
sensor a number of images of the collected light each obtained
after one of the filter transfer functions is applied, and to
process the acquired images according to the image processing
protocol to obtain a processed display image. The general-purpose
processor may be a real-time processor operative to generate a
processed display image within a time period on the order of the
persistence of human vision. It may also be operative to acquire
some images more slowly depending on the number of wavelengths and
complexity of diagnostic processing protocol. The sensor and filter
may be operative in the visible, infra-red, and UV regions.
In embodiments involving multiple fibers, light from each fiber may
be processed to generate an individual pixel for that fiber. The
pixels may then be arranged so that they form an image or display
which can be readily interpreted or read by the user.
Another embodiment of the invention is directed to an endoscopic
balloon probe having an infrared light source. This embodiment
includes a collection fiber, the collection fiber comprising a
proximal end, a distal collection end opposite the proximal end
adapted to collect infrared light, and a conductive core located
between the proximal end and the distal collection end, an
illumination fiber having a distal illumination end adjacent the
distal collection end of the collection fiber, and a proximate end
coupled to an infrared illumination source such as globar or other
means to orient image collection. An anchoring balloon is disposed
on the probe such that the distal collection end of the collection
fiber and the distal illumination end of the illumination fiber are
disposed inside the balloon. Preferably the balloon is infrared
lucent. A sheath may surround a portion of the collection fiber and
a portion of the illumination fiber. The collection fiber may have
a bend to orient the collection end in a radial direction with
respect to the axis of the conductive core, or may use other means
to orient image collection.
The present invention is also directed to novel methods for
analyzing or obtaining information about the properties of a tissue
or other surface of interest. One such method for obtaining
information about a surface of interest comprises the steps of
positioning a probe adjacent to the surface of interest, collecting
infrared light using the probe, transmitting the infrared light
from the surface to analyzing means, and analyzing the light to
determine one or more properties of the surface. The probe
preferably comprises a collection fiber, the collection fiber
comprising a proximal end, a distal collection end opposite the
proximal end adapted to collect infrared light, and an infrared
conductive core located between the proximal end and the distal
collection end, and a first anchoring balloon disposed on the
probe. The step of collecting infrared light preferably comprises
collecting infrared light in the vicinity of the collection end of
the probe that shines or radiates in a direction generally or
substantially perpendicular to the longitudinal axis of the probe.
The step of analyzing preferably comprises spectroscopic analysis.
More preferably, the step of analyzing comprises imaging
spectroscopy.
In a preferred method, the distal collection end of the probe lies
inside the balloon, and the balloon protects the collection end of
the probe from moisture and fouling. Alternately, the probe further
comprises a sheath which surrounds a portion of the collection
fiber. A first anchoring balloon is disposed on the sheath between
the proximal and distal collection end of the collection fiber. The
sheath has a portion that extends distally past the collection end
of the collection fiber, and the probe further comprises a second
anchoring balloon disposed on the portion of the sheath distal to
the collection end. When the tissue of interest is disposed in a
lumen, the method may further comprise the steps of inflating the
first balloon and the second balloon to create an enclosed volume
defined by the first balloon, the second balloon and the lumen, and
completely or partially filling the volume with a fluid, such as
dry nitrogen gas. The balloons may be inflated sequentially to
facilitate this process. For example, when the probe is inserted in
a blood vessel, the upstream balloon may be inflated first,
followed by the downstream balloon. The upstream balloon may be the
first or the second balloon, depending on whether the probe is
inserted antegrade or retrograde into the vessel. The fluid used to
fill the volume may be an infrared lucent gas or liquid, including
optical coupling fluids such as dry nitrogen gas. In a preferred
embodiment of the method, the distal collection end of the
collection fiber is inserted into the enclosed volume after the
balloons are inflated and the volume is filled with liquid.
Another embodiment is directed to a method for obtaining
information about a surface of interest comprising the steps of
positioning a probe adjacent to the surface of interest, collecting
light using the probe, transmitting the light from the surface to
analyzing means, and analyzing the light to determine one or more
properties of the surface. Preferably, the probe comprises a light
collection fiber bundle comprising a plurality of collection fibers
adapted to collect infrared light, each of the plurality of
collection fibers comprising a proximal end, a distal collection
end opposite the proximal end, and a conductive core located
between the proximal end and the distal collection end. The probe
is preferably adapted to collect infrared light. The step of
collecting light preferably comprises collecting light in the
vicinity of the collection end of the probe that radiates or shines
in a direction generally or substantially perpendicular to the
longitudinal axis of the probe. The step of analyzing preferably
comprises spectroscopic analysis, such as imaging spectroscopy,
standard or otherwise. Preferably, an anchoring balloon is disposed
on the probe such that the distal collection ends are disposed
inside the wall of the balloon.
Alternately, the probe may further comprise a sheath disposed
around the fiber bundle, a first anchoring balloon disposed on the
sheath between the collection ends and the proximal ends of the
plurality of fibers, and a second anchoring balloon disposed on the
sheath distal to the collection ends of the plurality of fibers. As
with the previous method, when the tissue of interest is disposed
in a lumen, the method may further comprise the steps of inflating
the first balloon and the second balloon to create an enclosed
volume defined by the first balloon, the second balloon and the
lumen, and emptying the volume or filling the volume with a fluid.
The fluid is preferably infrared lucent. In a preferred embodiment
of the method, the distal collection ends are inserted into the
enclosed volume after the balloons are inflated and the volume is
filled with the fluid.
Another embodiment of the invention is directed to a probe in which
the distal collection end of one or more collection fibers is
disposed in the central hole of a toroidally-shaped anchoring
balloon. This embodiment may optionally comprise one or more
illumination or excitation fibers disposed so that the distal
illumination end of the fiber or fibers are also disposed in the
central hole of the balloon. In these embodiments, excitation light
from the distal illumination end of the illumination fiber passes
through the inner wall of the balloon, the coupling fluid and the
outer wall of the balloon to reach the tissue surface. Likewise,
light coming from the tissue surface passes through the outer wall
of the balloon, the coupling fluid and the inner wall of the
balloon to reach the distal collection end of the probe.
Another embodiment of the present invention is directed to a method
for obtaining information about a tissue surface, comprising the
steps of collecting infrared radiation from the tissue surface
using a probe placed proximate to the tissue surface, the probe
having a longitudinal axis, transmitting the infrared radiation
from the tissue surface to a remote analyzer, and analyzing the
infrared information to determine properties of the tissue surface.
The step of analyzing may comprise spectroscopic analysis, such as
imaging spectroscopy, standard or otherwise. In addition, the step
of collecting and transmitting may be performed using multiple
fibers in the probe. The step of collecting infrared radiation may
comprise collecting infrared light in the vicinity of a collection
end of the probe that radiates or shines in a direction generally
or substantially perpendicular to the longitudinal axis of the
probe. Preferably, the probe has means for optically coupling the
collection end of the probe to the tissue surface. Such means
include all of the various balloon configurations previously
described. For example, the means for optically coupling may
comprise an anchoring balloon disposed around a collection end of
said probe. Alternately, the means may comprise a first anchoring
balloon and a second anchoring balloon disposed on said probe such
that a collection end of said probe is positioned between said
first and said second anchoring balloons. The two balloons may be
inflated as previously described, thereby removing or minimizing
the presence of infrared opaque substances between the tissue
surface and probe tip.
In one embodiment, the method further comprises the step of
providing a source of infrared radiation adjacent to the opposing
surface of the tissue surface being analyzed, and the step of
collecting comprises collecting the radiation transmitted through
the tissue to the probe.
Although the preferred embodiments disclosed herein are directed to
probes collecting infrared light, as will be clear to those of
skill in the art, other forms of electromagnetic radiation,
including but not limited to visible light, near-infrared light, or
any desired wavelength may be collected by appropriate
modifications to the probe. The balloons, sheaths, collection
fibers and/or illumination fibers described herein may be
disposable. In addition, although the probes of the invention have
been described primarily as useful in connection with medical
procedures, they may be used to evaluate any other desired
surface.
Other embodiments and uses of the invention will be apparent to
those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. All references
cited herein, including all U.S. and foreign patents and patent
applications, including, but not limited to, U.S. Provisional
Patent Application Serial No. 60/098,957 and U.S. application Ser.
No. 09/182,898, are specifically and entirely incorporated by
reference. The specification and examples should be considered
exemplary only with the true scope and spirit of the invention
indicated by the following claims.
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