U.S. patent application number 11/139904 was filed with the patent office on 2005-11-24 for multisensor probe for tissue identification.
This patent application is currently assigned to BioLuminate, Inc.. Invention is credited to Chase, Charles, Da Silva, Luiz, Hular, Richard.
Application Number | 20050261568 11/139904 |
Document ID | / |
Family ID | 25485656 |
Filed Date | 2005-11-24 |
United States Patent
Application |
20050261568 |
Kind Code |
A1 |
Hular, Richard ; et
al. |
November 24, 2005 |
Multisensor probe for tissue identification
Abstract
A multisensor probe for continuous real-time tissue
identification. The multisensor probe includes a tissue penetrating
needle, a plurality of sensors useful in characterizing tissue and
a position sensor to measure the depth of the needle into the
tissue being diagnosed. The sensors include but are not limited to
an optical scattering and absorption spectroscopy sensor, an
optical coherence domain reflectometry sensor, an electrical
impedance sensor, a temperature sensor, a pO.sub.2 sensor, a
chemical sensor and other sensors useful in identifying tissue. The
sensors may take the form of a plurality of optical fibers
extending through said needle. A retractable sheath may be disposed
around the distal section of the needle to protect the needle when
not in use. The sheath retracts when the probe is inserted into
tissue and the position of the sheath relative to the needle may be
measured to determine the needle's depth. Systems and methods for
tissue identification are also provided.
Inventors: |
Hular, Richard; (San Carlos,
CA) ; Da Silva, Luiz; (Danville, CA) ; Chase,
Charles; (Dublin, CA) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
755 PAGE MILL RD
PALO ALTO
CA
94304-1018
US
|
Assignee: |
BioLuminate, Inc.
San Carlos
CA
|
Family ID: |
25485656 |
Appl. No.: |
11/139904 |
Filed: |
May 26, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11139904 |
May 26, 2005 |
|
|
|
09947171 |
Sep 4, 2001 |
|
|
|
Current U.S.
Class: |
600/407 |
Current CPC
Class: |
A61B 2562/0242 20130101;
A61B 5/061 20130101; A61B 5/0084 20130101; A61B 2090/062 20160201;
A61B 5/0071 20130101; A61B 5/145 20130101; A61B 5/0075 20130101;
A61B 2017/00796 20130101; A61B 5/0066 20130101; A61B 5/6885
20130101; A61B 5/6848 20130101 |
Class at
Publication: |
600/407 |
International
Class: |
A61B 005/05; A61B
010/00 |
Claims
1. A multisensor probe for tissue identification comprising: an
elongate body having a distal section, a distal tip, and a lumen
extending through said elongate body to said distal tip; an optical
scattering and absorption spectroscopy sensor configured to deliver
and receive light from said distal tip of said elongate body; and a
position sensor incorporated into said probe and configured to
measure the depth said distal tip is inserted into said tissue.
2. The multisensor probe of claim 1 further comprising a slideable
sheath coaxially disposed over the distal section of said probe,
said sheath being retractable from said distal section as said
distal section of said elongate body is inserted into said
tissue.
3. The multisensor probe of claim 1 wherein said position sensor is
selected from the group consisting of an optical sensor, capacitive
sensor, resistive sensor, laser ranging, sonic sensor, and a
camera.
4. The multisensor probe of claim 1 wherein said position sensor is
an optical encoder.
5. The multisensor probe of claim 2 wherein the position sensor is
configured to read the position of said sheath relative to said
elongate body.
6. The multisensor probe of claim 1 further comprising a handle for
manipulating said multisensor probe.
7. The multisensor probe of claim 1 further comprising a marking
switch to identify a location in said tissue as said distal section
is inserted into said tissue.
8. The multisensor probe of claim 2 further comprising a spring to
urge the sheath over the distal section such that when said probe
is not in use, said sheath encloses said distal section of said
elongate body.
9. The multisensor probe of claim 1 further comprising a electrical
sensor for measuring electrical properties of said tissue.
10. The multisensor probe of claim 9 wherein the electrical sensor
comprises a first electrically conducting element and a second
electrically conducting element, said first and second electrically
conducting elements extending to the distal tip of said elongate
body.
11. The multisensor probe according to claim 10 wherein said first
electrically conductive element is said elongate body.
12. The multisensor probe of claim 11 wherein the elongate body is
a material selected from the group consisting of stainless steel,
aluminum, titanium, gold, and silver.
13. The multisensor probe of claim 12 wherein said second
electrically conductive element extends through said lumen.
14. The multisensor probe of claim 1 further comprising a memory
device capable of storing useful information about the probe.
15. The multisensor probe of claim 1 further comprising an OCDR
sensor, said OCDR sensor comprising an optical fiber extending
through said lumen to said distal tip.
16. The multisensor probe of claim 15 wherein the optical
scattering and absorption spectroscopy sensor includes at least
three optical fibers extending through said lumen to said distal
tip.
17. The multisensor probe of claim 16 wherein the elongate body has
an outer diameter less than or equal to that of a 18 gauge
needle.
18. The multisensor probe of claim 1 further comprising a P.sup.02
sensor.
19. The multisensor probe of claim 18 further comprising a
temperature sensor.
20. The multisensor probe of claim 19 wherein the temperature
sensor and pO.sub.2 sensor utilize a single fiber optic.
21. The multisensor probe of claim 1 wherein the distal tip of the
elongate body is sharp.
22. The multisensor probe of claim 21 wherein the distal tip
defines a plane and the plane forms an angle with an axis of said
elongate body, said angle ranging from 30 to 70 degrees.
23. A multisensor probe for tissue identification, said probe
connectable to a controller via a cable, said probe comprising: a
needle having a distal tip and a lumen extending through said
needle to said distal tip; and a plurality of optical fibers
extending from said controller, through said cable, through said
lumen, to said distal tip of said needle when said probe is
connected to said controller, wherein at least two of said
plurality of optical fibers are optical scattering and absorption
spectroscopy fiber optics and wherein at least one of said
plurality of optical fibers is an OCDR fiber optic, and wherein a
position sensor is incorporated into said probe, said position
sensor adapted to measure depth the needle is inserted into the
tissue.
24. The multisensor probe of claim 23 wherein the position sensor
is a sensor selected from the group consisting of a resistive
sensor and a linear optical encoder.
25. The multisensor probe of claim 23 having a conducting element
extending through said lumen.
26. The multisensor probe of claim 23 further comprising a
slideable sheath coaxially disposed over a distal section of said
needle, said sheath being retractable from said distal section as
said needle is inserted into said tissue.
27. The multisensor probe of claim 26 wherein the position sensor
is configured to read the position of said sheath relative to said
needle.
28. A method for identifying tissue comprising: manually inserting
a multisensor probe as recited in claim 1 into said tissue.
29. A tissue detection system comprising: a probe, said probe
comprising a multisensor needle comprising a plurality of optical
fibers, said probe further comprising a position sensor adapted to
sense depth of the needle into said tissue; and a controller
configured to deliver and collect light through said plurality of
optical fibers wherein at least one of said fibers is utilized as
an OCDR sensor configured for measuring backscattered and reflected
light as a function of depth into the tissue and wherein at least
one said optical fibers is utilized for optical scattering and
absorption.
30. The system of claim 29 further comprising at least one
electrode for sensing electrical information about the tissue.
31. The system of claim 29 further comprising a sheath which
retracts when the needle is inserted into said tissue.
32. The system of claim 31 wherein said position sensor measures
said position of said sheath relative to said needle.
33. A multisensor probe for tissue identification, said probe
connected to a controller via a cable, said probe comprising: a
handle to manipulate said probe; a needle joined to said handle,
said needle having a distal section, a distal tip and a lumen
extending through said needle to said distal tip; a plurality of
optical fibers extending from said controller, through said cable,
through said lumen, to said distal tip of said needle; a sheath
slideably disposed around said distal section of said needle, said
sheath being retractable into said handle when said distal section
of said needle is inserted into said tissue; and an optical
position sensor coupled to said sheath to measure position of said
retractable sheath relative to said handle, said position
corresponding to the depth of insertion of said needle into said
tissue.
34. The multisensor probe of claim 23 comprising a first light
collecting fiber extending to a first point and a second light
collecting fiber extending to second point wherein each of said
first collecting fiber and second light collecting fiber is useful
in optical scattering and absorption spectroscopy and wherein said
first point is proximal to said second point.
35. The multisensor probe of claim 34 wherein said first point is
proximal to said second point from 100 to 700 um.
36. The multisensor probe of claim 23 comprising a light collecting
fiber having a center and a light emitting fiber having a center
wherein said center of said light collecting fiber is separated
from said center of said light emitting fiber by 175 to 500 um.
37. The multisensor probe of claim 36 wherein said center of said
light collecting fiber is separated from said center of said light
emitting fiber by 300 to 500 um.
38. The multisensor probe of claim 10 wherein said elongate body is
made of a conducting polymer.
39. The multisensor probe of claim 14 wherein said memory device is
configured to detect whether said probe has been previously used in
a tissue identification procedure.
40. The multisensor probe of claim 39 wherein said memory device is
configured to prevent said probe from being used more than
once.
41. The multisensor probe of claim 1 wherein said position sensor
is a resistive sensor.
42. The multisensor probe of claim 1 wherein said position sensor
is configured to detect movement of a component of the probe that
is displaced as said distal tip is inserted into said tissue.
43. The multisensor probe of claim 16 wherein said optical fibers
include at least one multimode fiber and at least one single mode
fiber.
44. A multisensor probe for tissue identification comprising: a
handle; an elongate body extending from the handle, said elongate
body having a distal section, a distal tip, and a lumen extending
through said elongate body to said distal tip; an optical
scattering and absorption spectroscopy sensor configured to deliver
and receive light from said distal tip of said elongate body; and a
position sensor incorporated into said handle and configured to
measure the depth said distal tip is inserted into said tissue.
45. The multisensor probe of claim 1, wherein the position sensor
is configured to generate a measurement of the depth said distal
tip is inserted into said tissue.
46. The multisensor probe of claim 1, wherein the position sensor
comprises an electronic position sensor.
47. The multisensor probe of claim 23, wherein the position sensor
is configured to generate a measurement of the depth said distal
tip is inserted into said tissue.
48. The multisensor probe of claim 23, wherein the position sensor
comprises an electronic position sensor.
49. The method of claim 28, further comprising electronically
measuring the depth the distal tip of the probe is inserted into
the tissue.
50. The multisensor probe of claim 44, wherein the position sensor
is adapted to generate a measurement of the depth said distal tip
is inserted into said tissue.
51. The multisensor probe of claim 44, wherein the position sensor
comprises an electronic position sensor.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Ser. No.
09/947,171, filed Sep. 4, 2001, the entire disclosure of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] This invention is directed to tissue identification and in
particular, to a multisensor probe for identifying cancerous tissue
in vivo.
BACKGROUND
[0003] Every week in the United States about 19,000 open surgical
breast biopsies are performed on women. Only about 3000 cancers
will be found. Thus, about 85% of the biopsies are unnecessary.
This means about 16,000 women will needlessly undergo open surgical
breast biopsies in the U.S. every week because of the inaccuracy in
diagnosing cancerous tissue in the breast.
[0004] Open surgical breast biopsies are highly undesirable because
they are invasive and traumatic to the patient. In a surgical
biopsy, the suspected location of the abnormality would be marked
with a thin, hooked guide wire. The surgeon tracts the guide wire
to the location of the suspected abnormality and the suspect area
is excised. The open surgical biopsy is the most common form of
biopsy and is invasive, painful and undesirable to the patient. The
open surgical biopsies may also leave scar tissue which may obscure
the diagnostic ability of future mammograms, creating a major
handicap for the patient.
[0005] Another form of biopsy is a large-core needle biopsy (14
gauge needle). The standard core biopsies remove a 1 mm.times.17 mm
core of tissue. The large core needle biopsy is less invasive than
a surgical biopsy but still removes an undesirable amount of
tissue.
[0006] Still another form of biopsy is the stereo tactic fine
needle aspiration biopsy. In this type of biopsy, a small amount of
the cells are aspirated for cytological analysis. This procedure is
minimally invasive. A shortcoming, however, with stereo tactic
biopsies is poor accuracy. The poor accuracy is a result of the
small sample size which makes accurate cytology difficult.
[0007] Another drawback of typical biopsy procedures is the length
of time required for the laboratory to review and analyze the
excised tissue sample. The wait can take, on average, approximately
two months from the first exam to final diagnosis. Consequently,
many women may experience intense anxiety while waiting for a final
determination.
[0008] Various methods and devices have been developed to measure
physical characteristics of tissue in an effort to distinguish
between cancerous and non-cancerous tissue. For example, U.S. Pat.
No. 5,303,026 to Strobl et al. (the Strobl patent) describes an
apparatus and method for spectroscopic analysis of scattering media
such as biological tissue. More specifically, the Strobl patent
describes an apparatus and method for real-time generation and
collection of fluorescence, reflection, scattering, and absorption
information from a tissue sample to which multiple excitation
wavelengths are applied.
[0009] U.S. Pat. No. 5,349,954 to Tiemann et al. also describes an
instrument for characterizing tissue. The instrument includes,
amongst other things a hollow needle for delivering light from a
monochromator through the needle to a desired tissue region.
Mounted in the shaft of the needle is a photodiode having a light
sensitive surface facing outward from the shaft for detecting
back-scattered light from the tissue region.
[0010] U.S. Pat. No. 5,800,350 to Coppleson et al. discloses an
apparatus for tissue type recognition. In particular, an apparatus
includes a probe configured to contact the tissue and subject the
tissue to a plurality of different stimuli such as electrical,
light, heat, sound, magnetic and to detect plural physical
responses to the stimuli. The apparatus also includes a processor
that processes the responses in combination in order to categorize
the tissue. The processing occurs in real-time with an indication
of the tissue type (e.g. normal, pre-cancerous/cancerous, or
unknown) being provided to an operator of the apparatus.
[0011] U.S. Pat. No. 6,109,270 to Mah et al. (the Mah patent)
discloses a multimodality instrument for tissue characterization.
In one configuration shown in the Mah patent, a system with a
multimodality instrument for tissue identification includes a
computer-controlled motor driven heuristic probe with a
multisensory tip.
[0012] Notwithstanding the above, there still exists a need for a
convenient and reliable multisensor probe that can provide real
time analysis of multiple tissue properties. In particular, a
multisensor probe and system in accordance with the present
invention is desirable.
SUMMARY OF THE INVENTION
[0013] The present invention includes a multisensor probe for
tissue identification comprising an elongate body having a distal
section, a distal tip, and a lumen extending through the elongate
body to the distal tip. The probe further includes an optical
scattering and absorption spectroscopy (OSAS) sensor configured to
deliver and receive light from the distal tip of the elongate body
and a position sensor configured to measure the depth the distal
tip is inserted into the tissue. Suitable position sensors include
but are not limited to an optical sensor, capacitive sensor, or a
resistive sensor.
[0014] A variation of the present invention includes the
multisensor probe as described above wherein the probe further
includes a slideable sheath coaxially disposed over the distal
section of the elongate body. The sheath is retractable from the
distal section as the distal section of the elongate body is
inserted into the tissue. In a variation, the position sensor is
configured to read the position of the sheath relative to the
elongate body.
[0015] Another variation of the present invention includes the
multisensor probe as described above wherein the probe further
includes an electrical sensor. The electrical sensor is configured
to measure electrical properties of the tissue. The electrical
sensor includes a first electrically conducting element and a
second electrically conducting element. The first and second
electrically conducting elements extend to the distal tip of the
elongate body. In a variation, the elongate body is the first
conducting element. Suitable materials for the first conducting
element are stainless steel, aluminum, titanium, gold, silver, and
other electrically conducting materials.
[0016] Another variation of the present invention includes a
multisensor probe as described above wherein the probe further
includes a memory device capable of storing useful information
about the probe.
[0017] Another variation of the present invention includes the
multisensor probe described above wherein the probe further
includes a switch or push button for marking a location in the
tissue as the distal section is inserted into the tissue.
[0018] Another variation of the present invention includes the
probe as described above wherein the probe further includes
additional sensors. In this variation, the multisensor probe
additionally includes an optical coherence domain reflectometry
(OCDR) sensor having an optical fiber extending through the lumen
to the distal tip. In another variation, the probe further includes
a pO.sub.2 sensor and a temperature sensor. In one variation, the
temperature sensor and pO.sub.2 sensor utilize a single fiber
optic.
[0019] Another variation of the present invention includes the
multisensor probe as described above wherein the probe further
includes a form of a 18-21 gauge needle. In one variation, the
needle is blunt. In another variation the needle is sharp. In still
another variation the needle is cut and polished at an angle less
than 70 degrees and preferably ranging from 40 to 60 degrees.
[0020] Another variation of the present invention includes a
multisensor probe for tissue identification. The probe is connected
to a controller via a cable. The probe comprises a handle to
manipulate the probe and a needle joined to the handle. A plurality
of optical fibers extend from the controller, through the cable,
through the lumen, to the distal tip of the needle. The probe also
features a sheath slideably disposed around the distal section of
the needle. The sheath is retractable into the handle when the
distal section of the needle is inserted into the tissue. In this
variation, the probe includes an optical position sensor coupled to
the sheath to measure position of the retractable sheath relative
to the handle.
[0021] Another variation of the present invention includes a
multisensor probe for tissue identification. The probe includes a
needle having a distal tip and a lumen extending through the needle
to the distal tip and a plurality of optical fibers extending from
the controller, through the cable, through the lumen, to the distal
tip of the needle. In this variation, at least two of the plurality
of optical fibers are optical scattering and absorption fiber
optics and at least one of the plurality of optical fibers is an
OCDR fiber optic. In a variation, the multisensor probe further
comprises a linear optical encoder coupled to the needle to measure
position of the distal tip relative to the tissue.
[0022] Another variation of the present invention includes a
multisensor probe having a plurality of sensors configured as shown
in any one of FIGS. 5A-5H. This variation may also feature a
slideable sheath coaxially disposed over a distal section of the
needle. The sheath is retractable from the distal section as the
needle is inserted into the tissue. This variation also includes a
position sensor configured to read the position of the sheath
relative to the needle.
[0023] Another variation of the present invention includes a method
for identifying tissue comprising manually inserting a multisensor
probe as recited in any one of the above described probes.
[0024] Still another variation of the present invention is a tissue
detection system comprising a multisensor needle comprising a
plurality of optical fibers and a position sensor for determining
position of the needle relative to the tissue. The system also
includes a controller configured to deliver and collect light
through the plurality of optical fibers wherein at least one of the
fibers is utilized as an OCDR sensor and wherein at least one the
optical fibers is utilized for optical scattering and
absorption.
[0025] Additional aspects and features of the invention will be set
forth in part in the description which follows, and in part will
become apparent to those skilled in the art upon examination of the
following or may be learned by practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIGS. 1A and 1B are illustrations of a multisensor probe in
accordance with the present invention in an application.
[0027] FIG. 1C is a graph of a tissue property versus position for
the application illustrated in FIGS. 1A and 1B.
[0028] FIG. 2A is a partial perspective view of a distal section of
a multisensor probe in accordance with the present invention.
[0029] FIG. 2B is an end view of the multisensor probe shown in
FIG. 2A.
[0030] FIG. 3 is a schematic illustration of an optical scattering
and absorption spectroscopy system in accordance with the present
invention.
[0031] FIG. 4 is a schematic illustration of an OCT system in
accordance with the present invention.
[0032] FIGS. 5A-5H are cross sectional views of various multisensor
probes in accordance with the present invention.
[0033] FIG. 6 shows an exploded view of a multisensor probe in
accordance with the present invention.
[0034] FIG. 7 is a schematic illustration of a position sensor
system in accordance with the present invention.
[0035] FIG. 8 is a schematic illustration of a multisensor system
in accordance with the present invention.
[0036] FIG. 9 is a schematic illustration of a multisensor system
having a reference optical fiber.
[0037] FIG. 10 is another schematic illustration of a system in
accordance with the present invention.
[0038] FIGS. 11A and 11B are measured spectra for normal and
malignant tissue respectively using a probe in accordance with the
present invention.
DETAILED DESCRIPTION
[0039] The present invention includes a multisensor probe and
system for identifying tissue such as cancerous tissue. The
multisensor probe may be inserted into tissue and continuously
measure a plurality of properties of the tissue while penetrating
the tissue. A processing module may be provided to characterize the
tissue based on information including but not limited to
information received from the probe. The present invention may
further include a graphical interface to conveniently display (in
real time) results to a doctor while the doctor is inserting the
probe into the tissue.
First Embodiment
[0040] FIGS. 1A-1C illustrate an embodiment of the present
invention in an application. Referring to FIG. 1A, a multisensor
probe 10 is shown inserted in breast tissue 20. The multisensor
probe 10 includes a handle 14 for manually manipulating the probe
and a needle 16 extending from the handle. The distal tip of the
needle is shown at location A and is directed towards a suspicious
lesion 30. FIG. 1B shows the distal tip of the needle within the
suspicious lesion 30 at location C.
[0041] The probe 10 includes a plurality of sensors to measure
tissue properties which are useful in identifying tissue such as
cancerous tissue. The sensors may take many forms including, for
example, optical fibers for receiving and transmitting light to and
from the probe tip. The probe's position or depth is also measured
as the probe 10 is inserted into the tissue 20. These measurements
are preferably taken and processed continuously and in real time as
the probe penetrates the tissue.
[0042] FIG. 1C shows graphical output 40 from the procedure
illustrated in FIGS. 1A and 1B. In particular, graph 40 shows
continuous measurement of a tissue property as a function of depth
(or position). Location A corresponds to normal tissue; location B
corresponds to a lesion boundary or margin; location C corresponds
to the center of the lesion 30; and location D corresponds to
normal tissue distal to lesion 30. A review of graphical output 40
enables a doctor to diagnose a suspicious lesion in breast tissue
in real time.
[0043] FIGS. 2A and 2B show an enlarged view of a distal section of
a probe in accordance with the present invention. Referring to FIG.
2A, probe 100 is shown having an elongate body 200 and a lumen 205
extending therethrough. A plurality of optical fibers extend
through the lumen 205 to the distal end of the elongate body.
Preferably, the optical fibers are flush with the distal end of the
elongate body. It is preferred that the fibers or sensors contact
or nearly contact the tissue as the probe penetrates tissue to be
identified. Hereinafter, sensors include but are not limited to one
or more optical fibers and conductors used for sensing.
[0044] The elongate body 200 may be, for example, an 18 to 21 gauge
hypodermic type needle. The elongate body may have a length in the
range of 0.5 to 20 cm., more preferably between 4 and 10 cm.
Suitable materials for the elongate body are metals and plastics. A
preferred material for the elongate body or needle is stainless
steel. Suitable stainless steel tubing is available from Vita
Needle, Needham, Mass. However, the elongate body 200 may be
comprised of other materials and may have other sizes.
[0045] The needle 200 shown in FIG. 2A features a sharp distal end.
The distal end is preferably cut and polished after the optical
fibers and other sensors are positioned within the needle. Cutting
the needle after the optical fibers are positioned within the
needle allows the optical fibers to be cut flush with the distal
tip of the needle. Preferably, the needle end is cut and polished
at an angle .theta. less than 70 degrees, usually between 30 and 70
degrees and most preferably between 40 and 60 degrees. Angles less
than 70 degrees are preferred because a sharp end more easily
penetrates tissue. However, the distal end of the elongate body may
also be blunt. Blunt tips may be suitable for penetrating soft
tissue such as brain tissue.
[0046] The needle or elongate body may include outer markings which
can be read or otherwise detected to determine the position or
depth of the probe as it is inserted into tissue. Markings may be
read by a camera or a technician examining the procedure. Suitable
markings include but are not limited to bar code, magnetic codes,
resistive codes, and any other code which can provide position
information of a moving device.
[0047] FIG. 2B shows an end view of the needle 200 and is
illustrative of one sensor configuration in accordance with the
present invention. In particular, a conductor 250 is centrally
positioned in lumen 205 and a plurality of optical fibers 210, 220,
230, 240 are shown circumferencially positioned about the conductor
250. The optical fibers may be single mode or multimode depending
on their use, as will be discussed further below.
[0048] The optical fibers and conductor are preferably bonded
within lumen 205 using a biocompatible compound such as, for
example, F114 epoxy manufactured by TRA-CON, Inc. Bedford, Mass.
Filling the lumen with a bonding compound prevents tissue from
entering the needle tip as the probe is inserted into tissue.
[0049] Alternatively, the sensors may be molded or formed in the
probe. For example, a biocompatible polymeric material may be
coaxially formed around the individual sensors to form a solid
polymer needle having the fiber optics bonded therein.
[0050] The optical fibers are also preferably coated with a
reflective or metallic layer that prevents stray light from
entering the fibers. A suitable coating is, for example, a 2000A
aluminum coating.
[0051] The optical fibers are used to measure tissue properties as
the needle 200 is inserted into tissue. For example, optical fibers
210, 220, and 230 may be used as an optical scattering and
absorption spectroscopy (OSAS) sensor and optical fiber 240 may be
used as an optical coherence domain reflectometry (OCDR) sensor.
While OCDR optical fiber 240 is shown at the apex 255 of the
needle, the present invention is not so limited. For example, a
fiber optic used in an OSAS sensor may be positioned at the apex
255 of the needle. For some applications, it may be desirable to
have one fiber optic or wire positioned at the apex and
consequently extend deeper into the tissue than the other
sensors.
[0052] Optical Scattering and Absorption Spectroscopy
[0053] Optical fibers 210, 220 and 230 may be configured as an
optical scattering and absorption spectroscopy (OSAS) sensor. It is
to be understood that optical scattering and absorption
spectroscopy includes various optical measurement techniques which
use light scattering and absorption data to measure a target
sample. Non-limiting examples of OSAS techniques include elastic
scattering spectroscopy and inelastic scattering spectroscopy.
[0054] FIG. 3 is a schematic illustration of one exemplary optical
scattering and absorption spectroscopy system. In the optical
system shown in FIG. 3, two optical fibers within the probe needle
are present for measurement of the scattered light: an illumination
fiber to deliver light from one or more light sources to the
tissue, and a collection fiber to receive the scattered photons
from the tissue and deliver them to a detector. Light from the
fiber at the probe tip enters the tissue and is absorbed and
scattered. After multiple scattering events within the tissue, a
fraction of the incident light enters the collection fiber, which
is located near the illumination fiber. The collected light is
transported by the fiber back to the instrument body where a
grating spectrometer and CCD detector measures the scattered light
intensity as a function of wavelength. This measured intensity can
then be compared with the measured intensity for normal-tissue
scattered light. Instead of using a grating and CCD detector, the
scattered light may be measured with a series of detectors that use
optical filters to separate the different light signals. If the
light source includes multiple LED's or lasers then conventional
modulation techniques can be employed to separate the different
colors with electronic filters.
[0055] Each light source can provide light at a single wavelength
(e.g., a laser), a narrow band wavelength (e.g., a LED), or a broad
band wavelength (e.g., a xenon flash lamp) which is believed to be
differentially absorbed by malignant tissue relative to normal or
benign tissue. For example, it has been shown recently that some
malignant breast tumors absorb relatively less light in the
spectral range of 450-500 nm than normal breast tissue. See, for
example, Bigio et al., Diagnosis Of Breast Cancer Using
Elastic-Scattering Spectroscopy. Preliminary Clinical Results,
Jour. Biomed. Optics 5, 221-228 (2000) and U.S. Pat. No. 5,303,026.
Similarly, differential absorption in the region of 660 or 940 nm
is indicative of deoxygenated hemoglobin, which is believed to be
another indicator of malignancy.
[0056] The combination of three optical fibers (210, 220, and 230)
as shown in FIG. 2B thus can estimate the optical absorption and
scattering properties of tissue near the distal tip. In the
configuration shown in FIG. 2B, optical fiber 210 may be a
multimode optical fiber for emitting and collecting electromagnetic
radiation typically in the spectral range of 200 nm to 2000 nm.
Optical fibers 220 and 230 may also be multimode optical fibers for
collecting light propagating through the tissue in the vicinity of
the fibers. Fibers that can support multiple modes are preferred
because they are easier to align and are more effective at
collecting and transporting spatially incoherent light.
[0057] Note that the probe depicted in FIG. 2A shows OSAS light
collecting fiber 230 extending to a point proximal to light
collecting fiber 220. The present invention is not so limited and
includes extending multiple light collecting or other optical
fibers to identical or different points within the elongate body
200. A suitable configuration, for example, includes a first light
collecting fiber extending to a first point along the needle and a
second light collecting fiber extending to a second point wherein
the first point is proximal to the second point from 100 to 700 um
and more preferably from 100 to 400 um. Likewise, one or more light
collecting fibers may extend to a point equal, proximal or distal
to the tip of a light emitting fiber. When not extending to equal
locations, the separation distances can be from 100 to 700 um and
more preferably from 100 to 400 um. The above described fibers thus
can extend to (and be flush with) the distal tip of an angled or
"sharp" needle as well as a blunt needle. Staggering the optical
fibers as described above may also increase the path length of
photons traveling to the collecting fiber(s). This creates a longer
mean free path and may make the instrument more sensitive to low
concentrations where absorption is an important factor.
[0058] Note also the collecting fibers 220 and 230 are spaced apart
in the radial direction from emitting fiber 210. A suitable (center
to center) distance D.sub.1 for light collecting fiber 230 to light
emitting fiber 210 is from about 175 to 400 um. A suitable (center
to center) distance D.sub.2 for light collecting fiber 220 to light
emitting fiber 210 is about 300 to 500 um. Of course, when using a
needle having a larger inner diameter, fibers may be separated
greater distances.
[0059] Optical Coherence Domain Reflectometry
[0060] The multisensor probe 100 of FIG. 2B also features an
optical fiber 240 which can be used for performing optical
coherence domain reflectometry (OCDR). OCDR is an optical technique
which can be used to image 1-3 mm into highly scattering tissue.
The technique may use a bright, low coherence source in conjunction
with a Michelson interferometer to accurately measure backscattered
(or transmitted) light as a function of depth into the media. A
suitable interferometer is, for example, model 510 manufactured by
Optiphase, Van Nuys, Calif.
[0061] A schematic illustration of one OCDR system 400 which may be
used with the present invention is shown in FIG. 4. Optical output
from a low coherence super luminescent diode 410 is split in a
fiber optic coupler 420 and directed toward the sample 430 and
reference arms of the interferometer. Reflections from the
reference mirror 440 and backscattered light from the sample are
recombined at the splitter and propagated to the detector 450.
Constructive interference at the detector produces a signal when
the sample and reference optical path lengths are within the
longitudinal coherence length of the optical source (typically
<15 microns). The scanning mirror in the reference arm is used
to scan the detection point within the sample thereby generating a
single line scan analogous to the A-scan in ultrasound. This single
line scan is sometimes referred to as optical coherence domain
reflectometry (OCDR).
[0062] The fiber optic 240 used for OCDR is preferably a single
mode fiber. A suitable inner diameter for the fiber optic 240 is
125 microns. An OCDR sensor can provide information about the
optical properties of tissue along a single line defined by the
optical fiber 240 cone of optical emission. The axial spatial
resolution along this line is determined by the spatial coherence
of the optical source and is typically less than 15 microns. The
transverse spatial resolution is determined by the fiber optic and
tissue index of refraction and can vary from five microns near the
fiber tip to hundreds of microns several mm into the tissue.
[0063] In addition to single line scans as described above, a
cross-sectional or optical coherence tomography (OCT) image is
produced by scanning the optical fiber across the sample and
collecting an axial scan at each location. OCT techniques are
discussed in D. Huang, et al., Optical Coherence Tomography,
Science 254,1178(1991) and Swanson, et al., Optics Letters
17,151(1992).
[0064] Other OCDR and OCT systems which can be used with the
present invention are described in Colston et al., Imaging Of Hard
And Soft Tissue Structure In The Oral Cavity By Optical Coherence
Tomography, Appl. Optics 37, 3582(1998); Sathyam et al., Evaluation
Of Optical Coherence Quantitation Of Analytes In Turbid Media Using
Two Wavelengths, Applied Optics, 38, 2097(1999); and U.S. Pat. Nos.
5,459,570; 6,175,669; and 6,179,611.
[0065] Electrical Impedance
[0066] Probe 100 depicted in FIGS. 2A and 2B additionally includes
an electrical impedance sensor. Electrical impedance sensor in this
embodiment includes electrically conducting elongate body 200 and
conductor 250. Suitable materials for the elongate body in this
configuration include electrically conducting metals as well as
electrically conducting polymers. The distal tip of the elongate
body 200 and conductor 250 contact the tissue when the probe is
inserted into tissue. The impedance sensor can thus measure various
electrical properties including electrical impedance of the tissue
near the probe tip.
[0067] In a preferred embodiment the electrical impedance is
measured at multiple frequencies that can range from 1 kHz to 4
MHz, and preferably at 5, 10, 50, 100, 200, 500, 1000 kHz.
Electrical impedance is another measurement which is believed to be
useful in characterizing tissue, especially when combined with
other tissue properties.
[0068] In summary, FIGS. 2A and 2B illustrate a multisensor probe
100 having an OSAS sensor, an OCDR sensor, and an electrical
impedance sensor in accordance with the present invention.
[0069] Other Sensor Configurations
[0070] The sensor configurations of the present invention may vary
widely and may incorporate more or less sensors than those
described above.
[0071] FIGS. 5A to 5H illustrate cross sectional views of a
multisensor probe having various sensor configurations in
accordance with the present invention. The configurations shown in
these figures are exemplary and not intended to limit the present
invention which is defined by the appended claims.
[0072] In each of FIGS. 5A-5H, the needle or elongate body 500
circumferentially surrounds a plurality of sensors including OSAS
fiber optics 510; OCDR fiber optics 520; electrical impedance
electrodes 530; pO.sub.2 fiber optics 554; combination temperature
and pO.sub.2 fiber optics 550; temperature sensors 560; chemical
sensors 570.
[0073] Referring to FIGS. 5A-5C, the needle includes one or more
OSAS fiber optics 510, one or more OCDR fiber optics 520, and one
or more electrical conductors 530 for measuring electrical
properties such as electrical impedance. In each of FIGS. 5A-5C,
the elongate body 500 is electrically conducting and also used as
one of the conducting elements for the impedance sensor.
Consequently, the electrical impedance sensor in FIG. 5C includes 3
conducting elements.
[0074] The probe illustrated in FIG. 5D is identical to that shown
in FIG. 5C except that the elongate body 500 is not a conductor
used in sensing electrical impedance. The elongate body 500 may be
made of non-electrically conducting material in this configuration
such as a polymeric material.
[0075] As shown in FIGS. 5E-5G, other sensors may be included
within elongate body 500. The probes shown in FIGS. 5E-5G
additionally include a pO.sub.2 sensor 540, a temperature/pO.sub.2
sensor 550, and temperature sensor 560 respectively.
[0076] Temperature and pO.sub.2 measurements are believed to be
useful in identifying abnormal tissue. Malignant tumors are
frequently characterized by reduced pO.sub.2 and elevated
temperature levels relative to adjacent normal tissue or benign
tumors. One convenient all-optical way to measure pO.sub.2 is by
means of fluorescence of a dye that is quenched by the presence of
oxygen. In this approach, the tip of an optical fiber contained
within a probe needle is coated with a thin layer of an appropriate
fluorescent material. The tip of the fiber is at the tip of the
needle, and is in direct contact with the tissue. The fluorescent
material is excited by means of, for example, a blue LED located in
the instrument body at the proximal end of the fiber and, for
example, a red fluorescent light emitted by the material is
collected by the fiber and returned to the proximal end of the
fiber where it is spectrally or otherwise separated from the
excitation light. The fluorescence lifetime of the dye depends
inversely on the amount of oxygen that diffuses into the material
from the surrounding tissue.
[0077] The lifetime can be accurately measured by a technique in
which the excitation light is modulated at a convenient frequency
and the phase of the fluorescence signal is measured relative to
the phase of excitation. See Hoist et al., A Microoptode Array For
Fine-Scale Measurements Of Oxygen Distribution, Sensors and
Actuators B 38-39, 122-129 (1997). Since the phase of the
fluorescence signal depends on the lifetime, the phase measurement
provides a convenient way to measure P.sup.02 that is not affected
by coating uniformity or fiber transmission losses. Suitable oxygen
sensors which may be incorporated into the present invention are,
for example, fiber optic oxygen microsensors manufactured by
PreSens, GmbH.
[0078] Temperature may also be measured by an all-optical technique
that is essentially identical to the method used to measure
pO.sub.2. See Klimant et al., Optical Measurement Of Oxygen And
Temperature In Microscale: Strategies And Biological Applications,
Sensors and Actuators B 00 1-9 (1996). In the case of temperature,
a different fluorescent material whose lifetime is related to
temperature is coated on the fiber tip. A phase-fluorescence
detection scheme similar to the phase-fluorescence detection scheme
for detecting oxygen can be used for the temperature detection
sensor with, perhaps, a different excitation wavelength and a
different modulation frequency.
[0079] The temperature and oxygen sensors may be incorporated into
one optical fiber. This is illustrated in the probe shown in FIG.
5G. The combined oxygen and temperature sensor 560 could have, for
example, a tip coated with two dyes: one dye corresponding to the
oxygen and one dye corresponding to the temperature. The other
aspects of the temperature and oxygen detection would be similar to
the detection and processing techniques described above.
[0080] The multisensor probes depicted in FIGS. 5E-5G also include
an OSAS sensor 510, and OCDR sensor 520, and an impedance sensor
530. In FIGS. 5E-5G, the elongate body 500 is electrically
conducting and used as one of the conductors in an electrical
impedance sensor.
[0081] FIG. 5H illustrates yet another sensor configuration having
a chemical sensor. Suitable chemical sensors may include materials
(e.g., catalyst) which react to the tissue being penetrated and ion
sensors. The multisensor probe of FIG. 5H also includes an OSAS
sensor 510, an OCDR sensor 520, and an impedance sensor 530. The
elongate body acts as a second conductor element for the impedance
sensor.
[0082] While not shown, other sensors may be incorporated into the
elongate body 500 such as stiffness/elasticity sensors,
fluorescence sensors, velocity and accelerometer sensors, pressure
transducer or tube sensors, and any other sensor or tool so long as
it may fit within the lumen of the elongate body.
Second Embodiment
[0083] Another multisensor probe 600 in accordance with the present
invention is shown in FIG. 6. The multisensor probe 600 includes a
handle 610 and an elongate body or needle 620 extending from the
distal end of the handle. The needle 620 is shown within a
slideable sheath 630.
[0084] Sheath 630 is configured such that it retracts into the
handle 610 when the needle is inserted into tissue. When not
retracted, the slideable sheath 630 covers the needle 620 to
protect against accidental needle exposure. The sheath 630 is urged
over the needle using a resilient member 660 such as a spring. The
spring connects to the sheath and applies a force urging the sheath
over the full length of the needle. The force supplied by the
resilient member 660, however, is not so great that it inhibits
manipulation of the needle into the tissue. The resilient member is
thus selected or adjusted to allow the sheath to easily retract as
the needle is inserted into tissue. Suitable materials for the
sheath include polymeric materials, preferably hard.
[0085] The multisensor probe 600 may also include a locking member
such as a locking ring 665. The locking ring 665 may be set such
that movement of the sheath is prevented until the locking ring is
rotated. Locking the sheath over the needle is helpful to prevent
accidental needle exposure.
[0086] The multisensor probe shown in FIG. 6 features a shaft 640
inside the handle 610. The shaft is affixed within the handle and
provides a surface for the sheath to slide over when the sheath
retracts into the handle. The shaft may coaxially surround the
fiber optics, conductors and any other sensors to be used in the
multisensor probe. The needle 620 is aligned and attached to the
shaft such that the needle extends from the handle. The sensors and
optics within the shaft continue through the shaft and into the
needle. The sensor configurations may be similar to the sensor
configurations described above.
[0087] The fiber optic, electrical conductors and other sensors may
connect to a controller (not shown) which drives the sensors and
receives signals from the sensors. The sensor optics and wiring may
extend from the handle to the processor within a flexible cable
650. The flexible cable 650 holds and provides protection to the
sensors.
[0088] The flexible cable includes a proximal end (not shown) and a
distal end 653. The distal end of the cable 650 is joined to the
proximal end of the probe handle. In particular, FIG. 6 shows the
distal end of the cable joined to the proximal end of shaft 640.
While not shown, resilient members or connectors may be deployed at
the proximal end of the probe handle (i.e., the interface between
the cable to the handle) to prevent bending moments from damaging
the sensors within the cable.
[0089] The proximal end of the cable 650 (not shown) preferably
terminates at a optical connector or coupling. The coupling can be
removably connected to the processor. The connector, for example,
may be similar to a fiber optic ST connector. Thus, the multisensor
probe and flexible cable may be easily connected to the processor
prior to a procedure and removed from the processor following the
procedure. The multisensor probe 600 is, in this sense, disposable
after a use.
[0090] A memory device may also be incorporated into the probe or
the connector section of cable 650. The memory device could contain
information about the probe including calibration parameters.
Calibration parameters are useful for data analysis. In addition,
the memory device can be used to detect and prevent multiple uses
of the device. A suitable memory device that can be integrated with
the control electronics is GemWave.TM. C220 available from
GEMPLUS.
[0091] Position Sensor
[0092] The multisensor probe shown in FIG. 6 also includes a
position sensor 670. The position sensor 670 can be an optical
position sensor that measures light reflected off an encoded
surface of the sheath 630. Alternatively, the position sensor 670
could be a resistive or capacitive sensor that couples to a
conductor within the sheath 630.
[0093] Also, position sensor 670 can be a fiber optic that delivers
light from an external light source onto the sheath 630 and returns
the reflected light back to an external detector. The external
light source could have multiple wavelengths (e.g. red and green);
a color-coded pattern on the sheath having at least three different
colors would allow for detecting a change in position and direction
(e.g. red, green, black).
[0094] FIG. 7 is a schematic of an optical position sensing system
700 in accordance with the present invention. In FIG. 7, two
colored light emitting diodes (LEDs) 760 and 765 are powered by a
power supply 770. The power supply 770 may, for example, modulate
LEDs 760 and 765 at two different frequencies to allow electronic
separation of the two colors.
[0095] Light from the LEDs 760 and 765 is combined at fiber optic
slitter 775. The light then propagates through a second fiber optic
splitter 780 to fiber tip 785 where the light exits. The light
emitted from the fiber tip 785 reflects off color coded bar 790 and
returns through the splitter 780 to the optical detector 795.
[0096] Coded bar or encoder 790 may have various configurations. In
one variation, the color bar 790 has a repeated three-color pattern
(e.g., red, green, blue). As the color bar 790 moves past the fiber
tip 785 the relative amplitude of the two colors is decoded to
determine the bar color. By counting the number of bars and the
direction the control electronics can keep track of the bar
position relative to the initial starting point. The direction is
calculated by noting the sequence of color bars. In another
variation, color bar 790 has a continuous transition between two
different colors that each correspond to a signal maximum for each
LED color. The absolute position along the bar can be determined
form the relative intensity of each LED 760 and 765 of the optical
detector 795.
[0097] In another optical sensor in accordance with the present
invention, only one color LED is used and the color bar is selected
to produce at least three reflected intensity levels. This approach
may work with a continuous and a noncontinuous transition between
the color bars. However, this approach may be more susceptible to
noise than using multiple LEDs.
[0098] The above mentioned optical position sensors are described
in connection with a sheath 630 or like component. When the sheath
or other component is retracted as the needle is inserted, an
encoder on the sheath moves relative to a detection point on the
handle of the multisensor probe. However, the present invention is
not limited to the above noted position sensors. Any suitable
position sensor may be used and incorporated with the multisensor
probe of the present invention. For example, the depth of the
needle may be measured using a form of ranging technology wherein a
laser beam is emitted from the handle 610 to the tissue surface.
For example, the position of the handle relative to the tissue
surface may be determined based on the reflected signal of the
laser beam. Sonic and ultrasonic sensors may also be employed to
determine the position or depth of insertion of the needle.
[0099] Another position sensor in accordance with the present
invention is to provide visual marks on the needle. A person
watching the procedure could record the number of marks remaining
outside the surface as the needle is inserted into the tissue. Or,
a person may record the number of marks on the needle covered by
tissue as the needle is inserted into the tissue. A camera may be
provided to image the marked needle as it is pushed into tissue.
Image analysis would provide depth as a function of time. However,
one disadvantage of position sensors using ranging or imaging
techniques is that the user would have to avoid blocking the sensor
or camera.
[0100] Selected positions may be identified by pressing a button or
switch 680 of FIG. 6. When activated (e.g., pressed), the button
would identify or mark selected positions during insertion of the
probe. For example, the physician may press a switch or button when
the needle probe hits a suspect lesion boundary. The selected
position is marked and its location can be used later by analysis
software to distinguish normal tissue from suspicious tissue.
Suitable forms of markers include but are not limited to a lever,
button, voice recognition or foot switch.
[0101] Tissue Identification Systems
[0102] The multisensor probe of the present invention may be used
in conjunction with various tissue identification systems.
Typically, a tissue identification system would include a
multisensor needle probe, a control module and a flexible cable
that connects the probe to the control module. The control module
typically includes electromagnetic radiation sources, optical
detectors, electrical impedance measurement electronics, and
control electronics. Computer software may analyze data collected
during the procedure (e.g., continuously and in real time) and then
provide information about the tissue type.
[0103] A tissue identification system 800 in accordance with the
present invention is illustrated in FIG. 8. The system 800 includes
a multisensor probe 810, a cable 820, a measurement package 830, a
computer 840, and various I/O devices 850 connected to the
computer.
[0104] The measurement package 830 drives various sensors of the
probe and measures their responses. As discussed above, there may
be five sensors to the measurement package including: an optical
scattering and absorption spectroscopy instrument; an Optical
Coherence Domain Reflectometry instrument (OCDR); an Oxygen Partial
Pressure instrument (pO.sub.2); a temperature measurement
instrument (T); an electrical impedance measurement instrument (Z).
The measurement package may additionally feature, but need not to,
an Artificial Intelligence--Pattern Recognizer Engine (AIP)
860.
[0105] Digital Signal Processors (DSP) 870 can be used to control
and pre-process signals which are then fed into the Artificial
Intelligence--Pattern Recognizer Engine (AIP) along with the other
signals. The AIP 860 may be a specialized processor to perform
pattern matching on the data received from the other components of
the instrument package. Both artificial neural networks and
hierarchical cluster analysis can be employed to classify the data
against other data sets such as data sets generated during, for
example, clinical trials. Data can also be compared to normal
tissue samples at another location within the patient.
[0106] The electronics and processor are preferably configured to
take measurements continuously and in real time. Preferably, the
electronics and processor are configured to take measurements of
the tissue every 1 mm for an needle insertion speed of 1 cm/s and
more preferably, every 0.2 mm. This corresponds to sampling rate of
at least about 10 Hz and 50 Hz respectively. The above sampling
rate provides for determining tissue structure on a microscopic and
macroscopic scale (i.e., 10 micron to 10 centimeters).
[0107] The Control Computer 840 can provide a convenient human
interface and data management system. It may include, for example,
various input/output (I/O) devices such as but not limited to: a
graphics display for presenting data in real time, and prompting
the operator for inputs; a keyboard for the operator to control the
system and input information; a speaker for audible feedback; a
microphone for the operator to annotate readings; a foot switch for
the operator to tell the system to "tag" or mark specific data
points; a printer for hard copy results; a bar code scanner for
inputting patient ID; and a communication port to interface with
hospital or laboratory information systems and internet.
[0108] FIG. 9 shows a schematic of another tissue identification
system 900 in accordance with the present invention. The system 900
includes a multisensor probe 910, a cable 920 that connects the
probe to a connector 930 located on the control module 940. The
control module 940 includes electromagnetic radiation sources 950
which may be, for example, multiple lasers or white light sources
(e.g. "X-strobe" sold by Perkin Elmer Optoelectronics, Inc. Salem,
Mass.).
[0109] A fiber optic splitter 960 splits light from sources 950
into an emission fiber 970 and a reference fiber 975A. In this
embodiment, a reference fiber 975B goes to the probe and returns to
a detector 980. The reference fiber 975B preferably extends into
the handle of the probe and not into the needle.
[0110] By measuring signals of the reference fiber, fluctuations in
light delivery to the tip of the device due to cable motion may be
partly accounted for. Fluctuations may occur for a variety of
reasons including losses through the fiber due to bends in the
fiber. Each of the optical fibers in the probe likely experience
similar losses as the reference fiber. This assumption is more
accurate if the fibers have a similar numerical aperture, material
properties and are tightly packed and possibly bonded within the
cable. The fibers can be bonded using a soft polymer compound or
silicone.
[0111] The detection system shown in FIG. 9 features an OSAS sensor
and light is delivered to the sample via fiber 970. Light is
collected by two collection fibers 995, 1010 and is delivered from
the connector 930 to separate optical detectors 990, 1000.
[0112] Additionally, light from collection fiber 1010 is split at
splitter 1020 to deliver light to a fluorescence optical detector
1030. The fluorescence detector 1030 may be filtered with, for
example, notch filters (available from CVI Laser corp. Albuquerque,
N. Mex.) to block out the excitation laser light.
[0113] Optical detectors within the control module can be a grating
spectrometer (e.g. S2000 fiber optic spectrometer, sold by Ocean
Optics Inc., Dunedin, Fla.). Alternatively, the light sources may
be modulated (e.g. PMA Laser Diode Modules, supplied by Power
Technology Inc., Little Rock, Ark.) and electronic filters can be
used to measure the optical signal at each modulation frequency
which is different for each wavelength. When the light sources are
modulated, an optical detector can be a silicon photo detector
(e.g. PDA55, supplied by ThorLabs Inc. Newton, N.J.).
[0114] The tissue identification system 900 may also include an
OCDR sensor. The OCDR sensor preferably includes an optical fiber
extending to the distal tip of the needle probe 910. Additionally,
the control module preferably features an OCDR light source,
detector and measurement electronics 1040 (e.g. OCDR system
available from OptiPhase Inc., Van Nuys, Calif.). The OCDR fiber
1050 is used to both deliver and collect light from the needle
probe 910.
[0115] The tissue identification system 900 shown in FIG. 9 also
features an electrical impedance sensor. The electrical impedance
sensor operates with an electronics module 1060 and may include a
three-conductor cable 1070 extending to the distal tip of the probe
910.
[0116] A main electronics control module 1100 may power and control
the various components and acquire data from the detectors.
Analysis software may process the data and displays results on
display 1110. A variety of analysis techniques can be applied
including, for example, neural networks as described in U.S. Pat.
No. 6,109,270 to Mah et al. and hierarchical (and nonhierarchical)
cluster analysis as described, for example, in papers by I. J.
Bigio, et al, "Diagnosis of breast cancer using elastic-scattering
spectroscopy: preliminary clinical results" in Journal of
Biomedical Optics, 5(2), 221-228, (April 2000) and Multivariate
Data Analysis, Fifth Edition, by Hair, et al, (1998).
[0117] A preferred algorithm includes comparing measurements from
normal tissue to measurements of a suspect tissue area. This can be
carried out in real time as the probe is inserted. In particular,
tissue proximal to the target tissue provides a baseline value to
the suspect tissue. For example, when inserting the probe into the
breast to identify suspect tissue, the needle is inserted into the
breast in a direction towards the suspect tissue. The breast tissue
penetrated proximal to the suspect tissue may be used as a baseline
to compare to measurements of the suspect tissue.
[0118] Another procedure includes comparing probe measurements of
the suspect or target tissue to probe measurements taken from
another body location. For example, the probe may be inserted into
left breast tissue to provide a baseline. The probe may then be
inserted into the right breast having the suspect lesion.
Comparison of the baseline to the suspect tissue indicates whether
the suspect tissue is normal.
[0119] Additional information may be used in an analysis to
identify the suspect tissue. Additional information (e.g., patient
history) may be used to weight or affect measured values to make
the diagnosis more accurate. Further, any combination of useful
algorithms may be employed with tissue identification system of the
present invention so long as one algorithm does not exclude use of
another algorithm. Non limiting examples of other algorithms
include but are not limited to multiple regression analysis,
multiple discriminant analysis and multi-variable pattern
recognition.
[0120] FIG. 10 shows a schematic of another tissue identification
system 1200 in accordance with the present invention. The system
1200 includes a multisensor probe 1210 coupled to four sensor
modules which could be housed in a single control unit module (not
shown). In particular, the system 1200 includes an OCDR sensor, an
optical pO.sub.2 and temperature sensor, an electrical impedance
sensor, and an OSAS sensor. The OCDR sensor, an optical pO.sub.2
and temperature sensor and electrical impedance sensor may be
configured similar to the sensors described above.
[0121] The OSAS sensor includes a control module 1220, a light
emitting fiber 1230, and a light collecting fiber 1240. The control
module 1220 includes electromagnetic radiation sources 1250 which
may be, for example, multiple LEDs (e.g., five different wavelength
LEDs), white light sources, or lasers. Light emitted from radiation
sources 1250 is coupled into one fiber at first splitter 1260. The
light is delivered from first splitter 1260 to a second splitter
1270 where it splits into two optical fibers. One fiber leads to
reference detector 1290, and one fiber leads to the sample via
emitting source fiber 1230. Back scattered and fluorescence
generated at the tissue returns through fiber 1230 and at splitter
1270 couples into a fiber that leads to fluorescence detector 1280.
The light delivered to the fluorescence detector 1280 may be
filtered with, for example, notch filters (available from CVI Laser
Corp., Albuquerque, N. Mex.) to block out the excitation laser
light.
[0122] Light delivered to the sample reflects, transmits and is
absorbed by the sample. A collection fiber 1240 collects radiation
from the sample. Light collected in the collector fiber 1240 is
then delivered to a third optic splitter 1300 which splits the
light into two optics. One optic delivers light to a first detector
1310 which measures, for example, an OSAS signal and one optic
delivers light to a second detector 1320 which includes a filter to
measure fluorescence. The light delivered to the fluorescence
detector 1320 may be filtered with, for example, notch filters
(available from CVI Laser corp. Albuquerque, N. Mex.) to block out
the excitation laser light.
[0123] Applications
[0124] Applications for the present invention can vary widely. For
example, the present invention may be used to detect cancerous
tissue in the breast. The multisensor probe of the present
invention may also be used to characterize other types of
abnormalities found in other locations of the body. The probe of
the present invention may be used in vivo as described above or
alternatively, the probe may be used to identify tissue in vitro.
Preferably, the probe of the present invention is configured to
measure tissue properties in real-time and continuously as the
probe tip is inserted into a tissue sample. The probe of the
present invention is thus effective beneath the surface of an organ
or tissue sample (e.g., subcutaneously) and is not limited to
merely contacting a surface or surface area of tissue to be
diagnosed. While penetrating the tissue sample, signals from the
multiple sensors of the probe are immediately processed to quickly
diagnosis, identify or characterize the tissue.
[0125] The device of the present invention may also be used in
combination with other medical devices. For example, the needle of
the multisensor probe may be inserted through a cannula or other
tubular structure used in medical procedures.
[0126] The present invention also includes a method and device for
determining the approximate size of an abnormality such as a tumor.
The size of the tumor could be calculated based on marking the
boundaries of the suspicious lesion as discussed above. The
distance between the first and second boundary could be stored and
used in an algorithm to determine an approximate size of the
suspicious lesion.
EXAMPLES
[0127] A multisensor probe in accordance with the present invention
was built and tested. The probe featured a needle, a handle for
manipulating the handle, an OSAS sensor, and OCDR sensor, and an
impedance sensor. The OSAS sensor included a source fiber and two
collection fibers. The OCDR sensor included a single mode fiber.
The electrical impedance sensor included a central conductor as one
electrode and the outer needle wall as the second electrode.
[0128] A xenon flash lamp was used as a light source for the test
probe. FIGS. 11A and 11B show the spectrum of light collected by
two OSAS fibers during in-vitro testing for normal and malignant
tissue respectively. The line or "signature" represented by
"channel 2" represents light collected from one optical fiber and
the line represented by "channel 3" represents light collected from
another optical fiber. The "channel 2" optical fiber was closer
(center to center) to the light emitting fiber than the "channel 3"
fiber.
[0129] Amplitude as a function of lambda (nm) is plotted in FIGS.
11A and 11B. As evidenced by the data, significant differences in
tissue optical properties between normal and malignant tissue are
observed. In particular, data corresponding to the malignant tissue
(FIG. 11B) differs significantly from the data corresponding to the
normal tissue (FIG. 11A). The differences include but are not
limited to the amplitude as well as the slope of the amplitude.
Further, the data lines differ at various wavelength ranges such
as, for example, from 450 to 550 nm. Accordingly, the test probe of
the present invention may be used to detect or differentiate
malignant tissue from normal tissue.
[0130] All publications, patent applications, patents, and other
references mentioned hereinafter are incorporated by reference in
their entirety. To the extent there is a conflict in a meaning of a
term, or otherwise, the present application will control.
[0131] All of the features disclosed in the specification
(including any accompanying claims, abstract and drawings), and/or
all of the steps of any method or process disclosed, may be
combined in any combination, except combinations where at least
some of such features and/or steps are mutually exclusive. Each
feature disclosed, in this specification (including any
accompanying claims, abstract and drawings), may be replaced by
alternative features serving the same, equivalent or similar
purpose, unless expressly stated otherwise. Thus, unless expressly
stated otherwise, each feature disclosed is one example only of a
generic series of equivalent or similar features. The invention is
not restricted to the details of the foregoing embodiments. The
invention extends to any novel one, or any novel combination, of
the features disclosed in this specification (including any
accompanying claims, abstract and drawings), or to any novel one,
or any novel combination, of the steps of any method or process so
disclosed.
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