U.S. patent application number 14/301357 was filed with the patent office on 2014-12-04 for vessel imaging system and method.
The applicant listed for this patent is Technion Research and Development Foundation LTD.. Invention is credited to Dvir Yelin.
Application Number | 20140354789 14/301357 |
Document ID | / |
Family ID | 41347805 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140354789 |
Kind Code |
A1 |
Yelin; Dvir |
December 4, 2014 |
VESSEL IMAGING SYSTEM AND METHOD
Abstract
A system and a method for acquiring an image of a particle
flowing in a vessel, the system comprising a light source for
generating an illuminating light, an imaging probe for laterally
statically illuminating at least a portion of said vessel with the
illuminating light, a detection unit for detecting emitted light
from an illuminated portion of said particle, and a processor unit
for reproducing an image of the illuminated portion of said
particle from the emitted light.
Inventors: |
Yelin; Dvir; (Haifa,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Technion Research and Development Foundation LTD. |
Haifa |
|
IL |
|
|
Family ID: |
41347805 |
Appl. No.: |
14/301357 |
Filed: |
June 11, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12461558 |
Aug 17, 2009 |
8780176 |
|
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14301357 |
|
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61089132 |
Aug 15, 2008 |
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Current U.S.
Class: |
348/68 |
Current CPC
Class: |
G01J 3/0208 20130101;
A61B 1/00096 20130101; A61B 5/0068 20130101; G01J 3/02 20130101;
A61B 1/043 20130101; A61B 1/00165 20130101; A61B 1/05 20130101;
A61B 5/0075 20130101; G01N 21/65 20130101; G01J 3/443 20130101;
A61B 5/418 20130101; A61B 1/07 20130101; H04N 5/2256 20130101; A61B
5/0084 20130101; G01J 3/44 20130101; G01N 2021/653 20130101; A61B
5/0066 20130101; G01N 21/64 20130101; A61B 5/14546 20130101; G01J
3/10 20130101; A61B 5/02007 20130101; G01J 3/0218 20130101; A61B
1/06 20130101 |
Class at
Publication: |
348/68 |
International
Class: |
A61B 1/04 20060101
A61B001/04; A61B 1/06 20060101 A61B001/06; A61B 1/05 20060101
A61B001/05; H04N 5/225 20060101 H04N005/225 |
Claims
1. A method for acquiring an image of a particle flowing in a
vessel, the method comprising: laterally statically illuminating at
least a portion of said vessel with an illuminating light;
detecting emitted light from an illuminated portion of said
particle; and reproducing an image of the illuminated portion of
said particle from the emitted light.
2. The method of claim 1 wherein the image of the illuminated
portion of said particle is a two-dimensional (2D) image.
3. The method of claim 1 further comprising acquiring an image of a
cross-section of the portion of the vessel.
4. The method of claim 3 wherein the image of the cross-section of
the vessel comprises a cross-section of one or more particles in
the portion of the vessel.
5. The method of claim 1 further comprising spectrally dispersing
the illuminating light along an axis.
6. The method of claim 1 further comprising collimating the
illuminating light prior to spectrally dispersing the light.
7. The method of claim 1 wherein the illuminated portion of said
particle comprises a distinct spectral band.
8. The method of claim 1 wherein detecting light from the
illuminated portion of said particle comprises measuring a spectrum
of the emitted light.
9. The method of claim 1 further comprising creating interference
between the emitted light and a reference light to determine axial
location of the illuminated portion of said particle.
10. The method of claim 9 comprising reproducing a
three-dimensional (3-D) image of the illuminated portion of said
particle.
11-18. (canceled)
19. A system for acquiring an image of a particle flowing in a
vessel, the system comprising: a light source for generating an
illuminating light; an imaging probe for laterally statically
illuminating at least a portion of said vessel with the
illuminating light; a detection unit for detecting emitted light
from an illuminated portion of said particle; and a processor unit
for reproducing an image of the illuminated portion of said
particle from the emitted light.
20. The system of claim 25 wherein the imaging probe captures the
emitted light from the illuminated portion of said particle.
21. The system of claim 25 wherein the imaging probe is an
endoscope.
22. The system of claim 25 wherein the imaging probe is a
catheter.
23. The system of claim 25 wherein the image of the illuminated
portion of said particle is a two-dimensional (2D) image.
24. The system of claim 25 wherein the processor unit reproduces an
image of a cross-section of the portion of the vessel.
25. The system of claim 25 wherein the image of the cross-section
of the portion of the vessel comprises a cross-section of one or
more particles in the portion of the vessel.
26. The system of claim 25 wherein the detection unit comprises a
spectrometer for measuring a spectrum of the emitted light, a
camera for capturing a single shot of the emitted light, or a
single detector for measuring a wavelength of the emitted light, or
any combination thereof.
27. The system of claim 25 further comprising a diffraction grating
to spectrally disperse the illuminating light along an axis.
28. The system of claim 25 wherein the illuminated portion of said
particle comprises a distinct spectral band.
29-38. (canceled)
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/089,132, filed on Aug. 15, 2008, the
disclosure of which is incorporated herein by reference in its
entirety.
FIELD AND BACKGROUND OF THE INVENTION
[0002] The present invention, in some embodiments thereof, relates
to imaging devices and, more particularly, but not exclusively, to
imaging systems and methods for medical and scientific
applications.
[0003] Endoscopic confocal microscopy devices are extensively used
in minimally invasive medical diagnosis to look below tissue
surfaces and for intervention purposes. Confocal microscopy is a
technique generally used to acquire an image of a specimen and is
based on focusing illuminating light from a point source to a point
on the specimen, and focusing emitted light (responsive to the
illuminating light) from the illuminated point on the specimen unto
a small pinhole in an opaque screen. As only the emitted light from
the illuminated point is focused unto the hole, the emitted light
passes through the pinhole while all other light not emitted by the
point is substantially blocked out. A detector on the other side of
the screen detects the amount of emitted light passing through the
pinhole and quantifies the amount for image reproduction purposes.
As only one point in the specimen is illuminated at a time,
two-dimensional (2D) or three-dimensional (3D) imaging generally is
done by scanning over a regular raster (a rectangular pattern of
parallel scanning lines) in the specimen.
[0004] A technique generally used to integrate confocal microscopy
inside probes used in medical and scientific applications such as,
for example, endoscopic probes and catheters, is spectrally encoded
confocal microscopy (SECM). In SECM, the specimen is generally
scanned line by line, with illuminating light at a different
wavelength hitting each point along a line (each point on a line is
"encoded" by a different wavelength). Emitted light from each point
(each point emitting light at a different wavelength) is detected
by a detector and, spatial information of the specimen along the
line may be decoded by measuring the detected wavelengths. A 2D
image may be reproduced by relatively slowly scanning the encoded
lines mechanically within the probe.
[0005] An alternative technique to SECM is spectrally encoded
endoscopy (SEE). SEE described in "Volumetric sub-surface imaging
using spectrally encoded endoscopy", by D. Yelin et al, Optics
Express 1750/Vol. 16, No. 3/4 Feb. 2008; as follows: "Spectrally
encoded endoscopy (SEE) [7] is a recently developed technique that
utilizes wavelength to encode transverse image information. The SEE
probe, comprising a single optical fiber, a diffraction grating,
and a low NA lens, focuses spectrally dispersed light onto the
sample. In turn, each point along this line is illuminated by a
distinct spectral band. Each line of the image is acquired by
measuring the spectrum of light reflected from the sample and
returned back through the SEE probe using a high-speed spectrometer
that resides outside the body. The second dimension of the image is
obtained by moving the fiber at slow rates (e.g. 30 Hz). Without
the need for rapid transverse scanning at the distal end of the
endoscope, SEE allows video rate imaging to be performed through a
miniature (i.e. 350 .mu.m diameter) endoscopic device [13]. When
the SEE probe is placed in the sample arm of an interferometer, it
additionally can achieve three-dimensional topological, surface
imaging in real-time, by use of time [14] and spectral [13, 15]
domain low coherence interferometry."
SUMMARY OF THE INVENTION
[0006] According to an aspect of some embodiments of the present
invention there is provided a method for acquiring an image of a
particle flowing in a vessel, the method comprising laterally
statically illuminating at least a portion of the vessel with an
illuminating light, detecting emitted light from an illuminated
portion of the particle, and reproducing an image of the
illuminated portion of the particle from the emitted light.
Optionally, the image of the illuminated portion of the particle is
a two-dimensional (2D) image. Optionally, detecting light from the
illuminated portion of the particle comprises measuring a spectrum
of the emitted light. Optionally, detecting emitted light comprises
detecting fluorescence, second harmonic generation, third harmonic
generation, luminescence, Coherent anti-Stokes Raman scattering,
Raman scattering, multi-photon fluorescence, or phosphorescence, or
any combination thereof. Optionally, the method comprises confocal
gating of the emitted light.
[0007] According to some embodiments of the invention, the method
further comprises acquiring an image of a cross-section of the
portion of the vessel. Optionally, the image of the cross-section
of the vessel comprises a cross-section of one or more particles in
the portion of the vessel.
[0008] According to some embodiments of the invention, the method
further comprises spectrally dispersing the illuminating light
along an axis. Optionally, the method further comprises collimating
the illuminating light prior to spectrally dispersing the
light.
[0009] According to some embodiments of the invention, the method
further comprises creating interference between the emitted light
and a reference light to determine axial location of the
illuminated portion of said particle. Optionally, the method
comprises reproducing a three-dimensional (3-D) image of the
illuminated portion of the particle.
[0010] According to some embodiments of the invention, the method
comprises creating interference between the emitted light and a
reference light to determine an axial component of a speed of the
particle in the vessel.
[0011] According to some embodiments of the invention, the method
comprises sending the illuminating light through a single mode
optical fiber. Optionally, the method comprises sending the
illuminating light through a multi-mode optical fiber. Optionally,
the method comprises receiving the emitted light through a single
mode optical fiber. Optionally, the method comprises receiving the
emitted light through a multi-mode optical fiber.
[0012] According to some embodiments of the invention, the method
comprises varying the wavelength of the illuminating light.
Optionally, the illuminating light is a broad bandwidth light.
[0013] According to some embodiments of the invention, the method
comprises counting a number of particles in the vessel. Optionally,
the method comprises determining a location, a speed of flow, a
size, a length, a shape, a color, or a brightness of a particle, or
any combination thereof, in the vessel.
[0014] According to some embodiments of the invention, the method
further comprises acquiring the image of the particle in-vivo.
Optionally, the method comprises acquiring the image of the
particle ex-vivo (outside the body).
[0015] According to an aspect of some embodiments of the present
invention there is provided a system for acquiring an image of a
particle flowing in a vessel, the system comprising a light source
for generating an illuminating light, an imaging probe for
laterally statically illuminating at least a portion of the vessel
with the illuminating light, a detection unit for detecting emitted
light from an illuminated portion of the particle, and a processor
unit for reproducing an image of the illuminated portion of the
particle from the emitted light. Optionally, the image of the
illuminated portion of said particle is a two-dimensional (2D)
image. Optionally, the detection unit detects fluorescence, second
harmonic generation, third harmonic generation, luminescence,
Coherent anti-Stokes Raman scattering, Raman scattering,
multi-photon fluorescence, or phosphorescence, or any combination
thereof. Optionally, the imaging probe includes confocal gating of
the emitted light.
[0016] According to some embodiments of the invention, the imaging
probe captures the emitted light from the illuminated portion of
the particle. Optionally, the imaging probe is an endoscope.
Optionally, the imaging probe is a catheter. Optionally, the
imaging probe illuminates a portion of the particle in-vivo.
Additionally or alternatively, the imaging probe illuminates a
portion of the particle ex-vivo (outside of the body).
[0017] According to some embodiments of the invention, the
processor unit reproduces an image of a cross-section of the
portion of the vessel. Optionally, the image of the cross-section
of the portion of the vessel comprises a cross-section of one or
more particles in the portion of the vessel. Additionally or
alternatively, the processor unit counts a number of particles in
the vessel. Optionally, the processor unit determines a location, a
speed of flow, a size, a length, a shape, a color, or a brightness
of a particle, or any combination thereof, in the vessel.
[0018] According to some embodiments of the invention, the
detection unit comprises a spectrometer for measuring a spectrum of
the emitted light. Optionally, the detection unit comprises a
camera for capturing a single shot of the emitted light.
Optionally, the detection unit comprises a single detector for
measuring a wavelength of the emitted light.
[0019] According to some embodiments of the invention, the light
source transmits a broad bandwidth light. Optionally, the light
source transmits a wavelength swept light.
[0020] According to some embodiments of the invention, the system
further comprises a diffraction grating to spectrally disperse the
illuminating light along an axis. Optionally, the system further
comprises a collimator to collimate the illuminating light prior to
spectrally dispersing the light.
[0021] According to some embodiments of the invention, the system
further comprises a reference arm for creating interference between
the emitted light and a reference light to determine axial location
of the illuminated portion of the particle. Optionally, the
acquired image is a three-dimensional (3-D) image of the
illuminated portion of the particle. Optionally, the reference arm
creates interference between the emitted light and the reference
light to determine an axial component of a speed of the particle in
the vessel.
[0022] According to some embodiments of the invention, the system
comprises a single mode optical fiber for sending a single ray of
illuminating light from the light source to the imaging probe.
Optionally, the system comprises a multi-mode optical fiber for
sending multiple rays of illuminating light from the light source
to the imaging probe. Optionally, the system comprises a single
mode optical fiber for carrying a single ray of emitted light from
the imaging probe to the detection unit. Optionally, the system
comprises a multi-mode optical fiber for carrying multiple rays of
emitted light from the imaging probe to the detection unit.
[0023] According to some embodiments of the invention, the system
comprises a dichroic mirror to collect the fluorescence into an
optical fiber.
[0024] According to some embodiments of the invention, the system
further comprises a display unit for displaying the acquired
image.
[0025] According to some embodiments of the invention, the
illuminated portion of the particle comprises a distinct spectral
band.
[0026] According to some embodiments of the invention, a coherency
between the emitted light and a reference light is not less than 1
.mu.m and not greater than 10 mm.
[0027] Unless otherwise defined, all technical and/or scientific
terms used herein have the same meaning as commonly understood by
one of ordinary skill in the art to which the invention pertains.
Although methods and materials similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the invention, exemplary methods and/or materials
are described below. In case of conflict, the patent specification,
including definitions, will control. In addition, the materials,
methods, and examples are illustrative only and are not intended to
be necessarily limiting.
[0028] Implementation of the method and/or system of embodiments of
the invention can involve performing or completing selected tasks
manually, automatically, or a combination thereof. Moreover,
according to actual instrumentation and equipment of embodiments of
the method and/or system of the invention, several selected tasks
could be implemented by hardware, by software or by firmware or by
a combination thereof using an operating system.
[0029] For example, hardware for performing selected tasks
according to embodiments of the invention could be implemented as a
chip or a circuit. As software, selected tasks according to
embodiments of the invention could be implemented as a plurality of
software instructions being executed by a computer using any
suitable operating system. In an exemplary embodiment of the
invention, one or more tasks according to exemplary embodiments of
method and/or system as described herein are performed by a data
processor, such as a computing platform for executing a plurality
of instructions. Optionally, the data processor includes a volatile
memory for storing instructions and/or data and/or a non-volatile
storage, for example, a magnetic hard-disk and/or removable media,
for storing instructions and/or data. Optionally, a network
connection is provided as well. A display and/or a user input
device such as a keyboard or mouse are optionally provided as
well.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Some embodiments of the invention are herein described, by
way of example only, with reference to the accompanying drawings.
With specific reference now to the drawings in detail, it is
stressed that the particulars shown are by way of example and for
purposes of illustrative discussion of embodiments of the
invention. In this regard, the description taken with the drawings
makes apparent to those skilled in the art how embodiments of the
invention may be practiced.
[0031] In the drawings:
[0032] FIG. 1 schematically illustrates a functional block diagram
of an exemplary system for imaging a vessel, in accordance with an
embodiment of the present invention;
[0033] FIG. 2 schematically illustrates a functional block diagram
of an exemplary system for imaging a vessel using a broadband light
source, in accordance with some embodiments of the present
invention;
[0034] FIG. 3 schematically illustrates a functional block diagram
of an exemplary system for imaging a vessel using a broadband light
source and low coherence interferometry, in accordance with some
embodiments of the present invention;
[0035] FIG. 4 schematically illustrates a functional block diagram
of an exemplary system for imaging a vessel using a
wavelength-swept light source, in accordance with some embodiments
of the present invention;
[0036] FIG. 5 schematically illustrates a functional block diagram
of an exemplary system for imaging a vessel using a
wavelength-swept light source, and single mode and multi-mode
optical fibers including a beam splitter, in accordance with some
embodiments of the present invention;
[0037] FIG. 6 schematically illustrates a functional block diagram
of an exemplary system for imaging a vessel using a
wavelength-swept light source and single mode and multi-mode
optical fibers, in accordance with some embodiments of the present
invention;
[0038] FIG. 7A schematically illustrates an exemplary single-event
histogram from a cytometer, as known in the art;
[0039] FIG. 7B schematically illustrates an exemplary
cross-sectional image acquired by any exemplary system shown in
FIGS. 1-6, in accordance with an embodiment of the present
invention; and
[0040] FIG. 8 illustrates a flow chart of a method for acquiring an
image of a particle in a vessel, in accordance with an embodiment
of the present invention.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0041] The present invention, in some embodiments thereof, relates
to imaging devices and, more particularly, but not exclusively, to
imaging systems and methods for medical and scientific
applications.
[0042] An aspect of some embodiments of the present invention
relates to a system and a method for acquiring an image of a
particle (or more particles) flowing in a vessel by laterally
statically illuminating at least a portion of the vessel with an
illuminating light and reproducing the image of a portion of the
particle(s) included in the illuminated portion of the vessel by
detecting an emitted light produced by the particle(s) responsive
to the illuminating light. As used herein, the term "laterally
statically illuminating" refers to illuminating from a position
external to the vessel with an imaging probe which does not include
mechanical moving parts". For example, mechanical moving optical
elements are not used. The illuminated light is spectrally
dispersed along an axis of the portion of the vessel, and a
spectrum of the emitted light is measured. The emitted light may
include, but not be limited to, fluorescence, second harmonic
generation, third harmonic generation, luminescence, Coherent
anti-Stokes Raman scattering, Raman scattering, multi-photon
fluorescence, phosphorescence, or any combination thereof. The
method may include, but not be limited to, a use of a technique
such as SEE. Optionally, SECM is used.
[0043] The reproduced image may be a cross-sectional 2D image, or
optionally a 3D image, of the portion of the particle(s) included
in the illuminated portion of the vessel. For convenience
hereinafter, the term "portion of the particle(s) included in the
illuminated portion of the vessel" may be interchangeably used with
"illuminated particle" or "illuminated portion of the particle".
The reproduced image may additionally comprise a cross-sectional 2D
image, or optionally a 3D image, of the illuminated portion of the
vessel. For convenience hereinafter, the term "illuminated portion
of the vessel" may be interchangeably used with "illuminated
vessel".
[0044] A further aspect of some embodiments of the present
invention relates to performing in vivo, and optionally ex vivo,
flow cytometry wherein a plurality of particles in the vessel may
be substantially simultaneously counted and optionally examined
based on the acquired image. The term "in vivo" as used herein in
this disclosure, refers to inside a body, for example the body of a
patient. The term "ex vivo", as used herein in this disclosure,
refers to outside of the body, for example, as in vessels and/or
organs externally connected to the body (optionally artificial), as
in cultures, as in samples used in hydrodynamic-based flow
cytometry, and/or as in blood samples extracted from the body. The
system may determine a number of particles of different types in
the vessel, and optionally, their location, speed of flow, size,
length, shape, color, or brightness, or any combination thereof.
These particles may include, but not be limited to, red blood
cells, white blood cells, virus cells, amoeba, germ cells,
bacteria, toxins, medicines, nano-particles, DNA, RNA, among other
microscopic particles visible in light. The term "number" refers to
a discrete quantity, and may optionally be a statistic or a
relative number.
[0045] Current methods for detecting and quantifying various types
of cells circulating within a blood stream typically involve
extraction of blood from the subject (a patient or an animal)
followed by labeling and ex vivo detection. For example, in
standard flow cytometry, specific cell populations in a blood
sample, drawn from a subject and fluorescently labeled, are passed
in a flow stream to be interrogated by a light source (usually a
laser). Fluorescence and light scattering signals emitted, or
remitted, by the cells in response to the light source can be
employed to determine the types and the number of the cells. These
techniques suffer from a number of shortcomings. It is difficult to
use these techniques to obtain a valid population profile for a
cell type of interest that varies with time. These techniques can
also suffer from a significant time delay between sample collection
and analysis, leading to potential measurement inaccuracies.
[0046] Some in vivo techniques for detection of static and
circulating fluorescently labeled cells are also known. However,
these techniques typically show difficulty, or simply fail, in
tracking cells flowing at a high velocity, especially in the
arterial circulation, even when they capture images at video rates.
In addition, employing these techniques for extracting quantitative
information about the number and flow characteristics of a specific
cell population can be very tedious.
[0047] In addition, conventional techniques for detecting and
monitoring tumor progression and its response to available
treatment modalities suffer from similar shortcomings. Methods such
as histopathology and standard flow cytometry require taking tissue
biopsies or blood samples from the patient. Further, some
conventional non-invasive techniques, such as computed tomography,
magnetic resonance imaging, and ultrasound, can typically detect
only late-stage anatomical abnormalities.
[0048] Recently, confocal microscopy was demonstrated for in vivo
flow cytometry, by using a slit confocal apparatus. While this
technique allows fast acquisition times in vivo, cells are detected
by their fluorescence signals and not through confocal imaging.
[0049] In an embodiment of the present invention, the system
comprises a light source for generating the illuminating light; an
imaging probe which may be an endoscope, optionally a catheter, for
laterally illuminating the portion of the vessel and for capturing
the emitted light from the illuminated particle; a detection unit
for detecting the emitted light; a processing unit for reproducing
the image of the illuminated particle, and optionally, of the
illuminated vessel; and a display for displaying the 2D
cross-sectional image of the illuminated particle and/or
illuminated vessel, and optionally the 3D image. The processing
unit additionally performs all computations associated with flow
cytometry optionally displayed on the display.
[0050] The system may further include a reference arm for
interferometry to improve signal-to-noise ratio (S/N) and to create
interference between the emitted light and a low coherence
reference light so that an axial location of the illuminated
particle (for 3D imaging) may be determined. Coherency may range,
for example, from 1 .mu.m-10 mm, inclusively. Optionally, an axial
component of a speed of the illuminated particle is determined.
Optionally, Doppler imaging is used to determine the axial
component of the speed.
[0051] In some embodiments of the present invention, the light
source produces a broadband illuminating light. Optionally, the
light source produces a varying wavelength (wavelength-swept)
illuminating light. The illuminating light may comprise a
wavelength in the range from 600 nm-1.3 .mu.m. A potential
advantage of using light of greater wavelength is a reduction in
scattering and an increase in depth range.
[0052] In some embodiments of the present invention, the detection
unit may include a spectrometer for measuring a distinct spectral
band in the emitted light. Optionally, the detection unit is a CCD
(charge-coupled device) camera for capturing a single shot of the
emitted light. Optionally, the detection unit is a single detector
for measuring a (discrete) wavelength of the emitted light.
[0053] In some embodiments of the present invention, the imaging
probe is connected to the light source and to the detection unit
through a single-mode optical fiber. Optionally, the connection is
of the imaging probe to the light source is through a multi-mode
optical fiber. Optionally, the connection of the imaging probe to
the detection unit is through a multi-mode optical fiber.
[0054] In some embodiments of the present invention, broad
bandwidth light is coupled to a fiber coupler, collimated,
diffracted by a diffraction grating and focused onto a transverse
line within the flow, where each resolvable point includes a
limited range of wavelengths, optionally a single wavelength. Light
that is scattered back from the focal line is collected by an
objective lens, coupled back into the fiber, and then measured by a
fast spectrometer. This optical configuration permits a single-shot
line imaging, allowing fast confocal imaging across a vessel
without any scanning mechanism.
[0055] In some embodiments of the present invention, low coherence
interferometry is used to achieve depth information. By adding the
reference arm, emitted light interferes with a reference light,
which allow determining an axial location (along a z-axis) of the
illuminated particle, as well as increase sensitivity and speed of
the system. Using the coherence gate allows using a lower
numerical-aperture lens which simplifies the system and provide
larger depth range.
[0056] In some embodiments of the present invention, the system
uses a rapid wavelength-swept source and a single photo detector.
Potential advantages to this approach include simpler, more compact
detection scheme that is less sensitive to misalignments, easier
fluorescence detection, and/or more efficient signal collection
using a double clad fiber or other incoherent waveguide.
[0057] In some embodiments of the present invention, the system
includes separate illumination and emitting light collection
channels. A single-mode fiber is optionally used for
high-resolution illumination while a multimode fiber with larger
core is optionally used to collect the backscattered and/or
fluorescence light after passing through a beam splitter. This
technique potentially improves one or more of signal efficiency,
depth of field, speckle noise and reduces undesired back
reflections from the optical setup. This configuration may also be
useful for fluorescence detection, where the multimode fiber
collects the fluorescence using a dichroic mirror instead of a beam
splitter. A separation in space between the fluorescence and the
excitation light is optionally provided and used to enable signal
collection without a beam splitter.
[0058] A potential main benefit of spectrally encoded imaging for
flow cytometry include imaging probes is that they are extremely
compact and simple with no scanning or moving parts, and high
spatial and temporal resolution imaging of the flowing particles or
cells. The system can be constructed in a single unit using
free-space optics or fiber optic, or in two units wherein one
contains the light source, detection, analysis and display
subsystems, and the other contains the compact probe with the
distal optics. The two units are connected by only one or a few
optical fibers. Potential applications include in vivo and ex vivo
flow cytometry for industrial and for clinical applications. For in
vivo applications, compactness of the probe, its simplicity, and
its, lack of moving parts, may allow for performing endoscopic flow
cytometry in various locations in the body. Exemplary dimensions
for the imaging probe may be, but not be limited to, 20 mm.times.5
mm.times.5 mm; 15 mm.times.7 mm.times.5 mm; and 20 mm.times.6
mm.times.5 mm.
[0059] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not
necessarily limited in its application to the details of
construction and the arrangement of the components and/or methods
set forth in the following description and/or illustrated in the
drawings and/or the Examples. The invention is capable of other
embodiments or of being practiced or carried out in various
ways.
[0060] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not
necessarily limited in its application to the details set forth in
the following description or exemplified by the Examples. The
invention is capable of other embodiments or of being practiced or
carried out in various ways.
[0061] Referring now to the drawings, FIG. 1 schematically
illustrates a functional block diagram of an exemplary system 100
for imaging a vessel 116, in accordance with an embodiment of the
present invention. System 100 includes a light source 102, an
imaging probe 106 including optical elements 107, a detection unit
110, a processor unit 112, and a display unit 114.
[0062] According to an embodiment of the present invention, system
100 acquires an image of one or more of a same type, or optionally
a different type, of particles flowing in vessel 116, for example
as shown by particles 120, 122 and 124 in body fluid 118, by
laterally statically illuminating a portion of the vessel with an
illuminating light 108 produced by light source 102, and detecting
an emitted light (not shown) produced by the particles. Optionally,
system 100 acquires an image of vessel 116. Optionally, system 100
includes a use of SEE. Optionally, system 100 includes a use of
SECM. Particles 120-124 may include red blood cells, white blood
cells, virus cells, amoeba, germ cells, bacteria, toxins,
medicines, nano-particles, DNA, RNA, among other microscopic
particle visible in lights. Vessel 116 may include veins, arteries,
capillaries, artificial vessels, lymph, urinary tract, and other
ducts internal, or optionally external, to the body and which may
carry body fluids and particles.
[0063] Illuminating of the portion of vessel 116 may be performed
by imaging probe 106, which may include for example, an endoscope,
optionally a catheter. Illuminating light 108, which may include a
broadband illuminating light or a wavelength-swept illuminating
light, is guided from light source 102 to imaging probe 106 by an
optical waveguide 104, which may include, for example a single
optical fiber, or optionally, multiple optical fibers. Optical
fiber 104 may be a single-mode optical fiber or optionally, a
multi-mode optical fiber. Optionally, optical waveguide 104 may
comprise reflecting mirrors and/or other optical elements suitable
for directing light. Illuminating light 108 is spectrally dispersed
along an x-axis and a y-axis of vessel 116 by optical elements 107
in imaging probe 106 which include a diffraction grating.
Optionally, illuminating light 108 is spectrally dispersed along a
z-axis. Illumination light 108 may comprise a wavelength in the
range from 600 nm-1.3 .mu.m. A potential advantage of using light
of greater wavelength is a reduction in scattering and an increase
in depth range.
[0064] Imaging probe 106 additionally collects the emitted light
from particles 120-124, and optionally from vessel 116, and
optically converts the emitted light using optical elements 107 for
guiding to detection unit 110. The emitted light may include, but
not be limited to, fluorescence, second harmonic generation, third
harmonic generation, luminescence, Coherent anti-Stokes Raman
scattering, Raman scattering, multi-photon fluorescence,
phosphorescence, or any combination thereof. Optionally, capturing
of emitted light is done by a second light capturing probe. Guiding
of the emitted light from imaging probe 106 to detection unit 110
is done through optical fiber 104. Optionally, guiding is done
through a second optical fiber, which may be a single-mode optical
fiber, or optionally, a multi-mode optical fiber.
[0065] Emitted light captured by imaging probe 106 is detected by
detection unit 110, and an output associated with a measure of a
spectrum of the emitted light is generated for processing by
processing unit 112. Detection unit 110 is selected according to
the emitted light to be detected, and may include a spectrometer
for measuring a distinct spectral band in the emitted light, a CCD
camera for capturing a single shot of the emitted light, or a
single detector for measuring a discrete wavelength of the emitted
light, or any combination thereof. The emitted light may also be
subject to low coherence interferometry with a reference light in
reference arm 115 so that an axial (z-axis) location of particles
120-124 may be determined and used to obtain a 3D image.
Optionally, an axial component of a speed of particles 120-124 is
determined. Optionally, Doppler imaging is used to acquire the
axial component of the speed of the particle.
[0066] According to an embodiment of the present invention,
processing unit 112 processes the output from detection unit 110
and reproduces the acquired image of particles 120-124, and
optionally vessel 116 and/or body fluid 118, for display on display
unit 114. The reproduced image may be a cross-sectional 2D image
along an x-axis and a y-axis, or optionally a 3D image (depth along
a z-axis), of particles 120-124. The reproduced image may
additionally comprise a cross-sectional 2D image, or optionally a
3D image, of the portion of vessel 116 and/or body fluid 118.
Optionally, the reproduced image may include information related to
the velocity of the particles.
[0067] According to an embodiment of the present invention, system
100 performs in vivo, and optionally ex vivo, flow cytometry. Based
on the output of detection unit 110, processing unit 112 may
simultaneously count, and optionally examine, particle 120-124, and
may compute a number of particles of different types in vessel 116,
and optionally, their location, speed of flow, length, shape,
color, or brightness, or any combination thereof. The results of
the computation may be displayed in display unit 114. Optionally,
the results may be stored in magnetic media or other data storage
means, printed, displayed by means other than display unit 114, or
any combination thereof.
[0068] Reference is made to FIG. 2 which schematically illustrates
a functional block diagram of an exemplary system 200 for imaging a
vessel 216 using a broadband light source 202, in accordance with
some embodiments of the present invention. Vessel 216 is shown
under tissue 217, and comprises body fluid 218 and particles 220,
222 and 224, which may be similar to that shown in FIG. 1 at 116,
118, 120, 122, and 124.
[0069] System 200, which may be similar to that shown in FIG. 1 at
100, comprises broadband light source 202 which may include a
super-luminescent diode array; an optical waveguide 204 which may
include an optical fiber; an imaging probe 206 including optical
elements comprising a diffraction grating 207A for diffracting
illuminating light 208, a collimator 207B for collimating the
illuminating light, and a high NA focusing lens 207C for focusing
the illuminating light; a spectrometer 210 including a CCD camera
210A, a collimator 210A for collimating an emitted light 209 and a
diffraction grating 210B for diffracting the emitted light; a
processing unit 212; and a display unit 214. Broadband light source
202; optical waveguide 204; imaging probe 206 including diffraction
grating 207A, collimator 207B, and lens 207C; CCD camera 210 with
collimator 210A and diffraction grating 210B; processing unit 212;
and display unit 214; may be similar to that shown in FIG. 1 at
102, 104, 106 including 107, 110 ,112, and 114.
[0070] According to some embodiments of the present invention,
single-shot line imaging, and fast confocal imaging across vessel
216 is performed, without any scanning mechanism. Broad bandwidth
illuminating light from light source 202 is coupled to optical
fiber 204, collimated, spectrally diffracted and focused onto a
transverse line (focal line) within a flow of body fluid 218 and
particles 220-224 inside vessel 216, where each resolvable point on
the line contains a single wavelength (each point is illuminated by
a distinct spectral band). Emitted light 209 from each lines is
collected by imaging probe 206, coupled back into fiber 204, and
measured by fast spectrometer 210. An output of spectrometer 210 is
processed by processing unit 212 and displayed on display unit
214.
[0071] FIG. 3 schematically illustrates a functional block diagram
of an exemplary system 300 for imaging a vessel 316 using a
broadband light source 302 and a reference arm 315, in accordance
with some embodiments of the present invention. Vessel 316 is shown
under tissue 317, and comprises body fluid 318 and particles 320,
322 and 324, which may be similar to that shown in FIG. 1 at 116,
118, 120, 122, and 124.
[0072] System 300, which may be similar to that shown in FIG. 1 at
100, comprises broadband light source 302 which may include a
super-luminescent diode array; an optical waveguide 304 which may
include an optical fiber; an imaging probe 306 including optical
elements comprising a diffraction grating 307A for diffracting
illuminating light 308, a collimator 307B for collimating the
illuminating light, and a focusing lens 307C for focusing the
illuminating light; a spectrometer 310; a processing unit 312; a
display unit 314; and reference arm 315. Broadband light source
302; optical waveguide 304; imaging probe 306 including diffraction
grating 307A, collimator 307B, and lens 307C; spectrometer 310;
processing unit 312; display unit 314; and reference arm 315; may
be similar to that shown in FIG. 1 at 102, 104, 106 including 107,
110, 112, 114, and 115.
[0073] According to some embodiments of the present invention, low
coherence interferometry in the range of 1 .mu.m-10 mm,
inclusively, is used to achieve depth information (3D topological
information). The interferometry may be in the time domain and/or
spectral domain. Reference arm 315, which may be included in a
single-mode Michelson interferometer, creates interference between
emitted light (not shown) from illuminated particles 320-324, and
optionally from vessel 316 and/or body fluid 318, and a reference
light, which allows for processing unit 312 determination of an
axial (z-axis) location of the particles. Optionally, reference arm
315 may be included in a multi-mode Michelson interferometer.
Optionally, reference arm 315 may be included in any other type of
interferometer suitable for creating the interference. Optionally,
system 300 sensitivity is increased. Optionally, system 300 imaging
speed is increased. Optionally, a lower numerical aperture lens
307C may be used, reducing a complexity of system 300 and
increasing a depth range. Optionally, Doppler imaging is used to
determine the axial component of the velocity of the particle.
[0074] Broad bandwidth illuminating light from light source 302 is
coupled to optical fiber 304, collimated, diffracted and focused
within a flow of body fluid 318 and particles 320-324 inside vessel
316, where each resolvable point on the line contains a single
wavelength. Emitted light 309 is collected by imaging probe 306,
coupled back into fiber 304 and into reference arm 315, and
measured by spectrometer 310. An output of spectrometer 310 is
processed by processing unit 312 and displayed on display unit 314,
and may include a 3D image or particles 320-324, vessel 316, or
body fluid 318, or any combination thereof.
[0075] FIG. 4 schematically illustrates a functional block diagram
of an exemplary system 400 for imaging a vessel 416 using a
wavelength-swept light source 402, in accordance with some
embodiments of the present invention. Vessel 416 is shown under
tissue 417, and comprises body fluid 418 and particles 420, 422 and
424, which may be similar to that shown in FIG. 1 at 116, 118, 120,
122, and 124. System 400, which may be similar to that shown in
FIG. 1 at 100, comprises a wavelength-swept light source 402 for
producing illumination light of varying discrete wavelengths; an
optical waveguide 404 which may include an optical fiber; an
imaging probe 406 including optical elements comprising a
diffraction grating 407A for diffracting illuminating light 408, a
collimator 407B for collimating the illuminating light, and a
focusing lens 407C for focusing the illuminating light; a detection
unit 410 which may include a single-element photo detector; a
processing unit 412; and a display unit 414. Wavelength-swept light
source 402; optical waveguide 404; imaging probe 406 including
diffraction grating 407A, collimator 407B, and lens 407C; photo
detector 410; processing unit 412; and display unit 414; may be
similar to that shown in FIG. 1 at 102, 104, 106 including 107,
110, 112, and 114.
[0076] According to some embodiments of the present invention,
confocal imaging of a diffracted wavelength-swept illumination
light 408 is done by relatively rapidly changing the wavelength of
the light such that every point along a focal line in vessel 416 is
illuminated (encoded) with a different wavelength while scanned one
point at a time. By using point-by-point illumination, a need for
spectral detection of the emitted light is eliminated and detection
may be performed by a single-element photo detector 410.
[0077] Wavelength-swept illuminating light from light source 402 is
coupled to optical fiber 404, collimated, diffracted and focused
point-by-point within a flow of body fluid 418 and particles
420-424 inside vessel 416 such that each point is illuminated
one-at-a-time by light of a single wavelength (by scanning one at a
time). Emitted light 409 from each point in each line is collected
one-by-one by imaging probe 406, coupled back into fiber 404, and
measured by single-element photo detector 410. An output of photo
detector 410 is processed by processing unit 412 and displayed on
display unit 414.
[0078] FIG. 5 schematically illustrates a functional block diagram
of an exemplary system 500 for imaging a vessel (not shown) using a
wavelength-swept light source 502, and a single-mode optical
waveguide 504A and a multi-mode optical waveguide 504B for guiding
an illumination light 508A and an emitting light 508B,
respectively, in accordance with some embodiments of the present
invention.
[0079] System 500, which may be similar to that shown in FIG. 1 at
100, comprises wavelength-swept light source 502 for producing
illumination light of varying discrete wavelengths; single-mode
optical waveguide 504A and multi-mode optical waveguide 504B which
may each include an optical fiber; an imaging probe 506 including
optical elements comprising a diffraction grating 507A for
diffracting illuminating light 508A, a collimator 507B for
collimating the illuminating light, a focusing lens 507C for
focusing the illuminating light, a coupler 507D for coupling
emitting light 508B to optical fiber 504B, and a beam splitter 507E
for splitting the emitted light; a detection unit 510 which may be
a single-element photo detector; a processing unit 512; and a
display unit 514. Optionally, beam splitter 507E may be a dichroic
mirror for fluorescence detection. Wavelength-swept light source
502; optical waveguides 504A and 504B; imaging probe 506 including
diffraction grating 507A, collimator 507B, lens 507C, coupler 507D,
and beam splitter 507E; photo detector 510, processing unit 512,
and display unit 514, may be similar to that shown in FIG. 1 at
102, 104, 106 including 107, 110, 112, and 114.
[0080] System 500 is configured such that a proximal unit 501
includes light source 502, photo detector 510, processing unit 512,
and display unit 514 with imaging probe (distal unit) 506 distally
located. Connection of imaging probe 506 to proximal unit 501 is
through optical fibers 504A and 504B.
[0081] According to some embodiments of the present invention,
single-mode optical fiber 504A is used for high-resolution
illumination while multi-mode optical fiber 504B with a larger core
collects a backscattered/fluorescence emitted light 508B after
passing through beam splitter 507E, optionally the dichroic mirror.
Wavelength-swept illuminating light from light source 502 is
coupled to optical fiber 504A, collimated, diffracted and focused
onto a transverse line (focal line) in a vessel (not shown), where
each resolvable point on the line contains a single wavelength
(each point is illuminated by one by one by scanning one at a
time). Emitted light 509 from each point in each line is collected
one-by-one by imaging probe 506, split into separate beams by beam
splitter 507E, optionally the dichroic mirror, and coupled into
multi-mode optical fiber 504B. The beams are measured by
single-element photo detector 510 and an output of the photo
detector is processed by processing unit 512 and displayed on
display unit 514.
[0082] FIG. 6 schematically illustrates a functional block diagram
of an exemplary system 600 for imaging a vessel (not shown) using a
wavelength-swept light source 602, and a single-mode optical
waveguide 604A and a multi-mode optical waveguide 604B for guiding
an illumination light 608A and an emitting light 608B,
respectively, in accordance with some embodiments of the present
invention.
[0083] According to some embodiments of the present invention,
spatially separating between fluorescence in the illuminated
particle and/or illuminated vessel, and an illuminating light 608A,
allows for using system 500 shown in FIG. 5 without a beam
splitter. Therefore, system 600 may be similar to system 500 with
the exception that the system does not include beam splitter 507E
shown in FIG. 5.
[0084] System 600 comprises wavelength-swept light source 602 for
producing illumination light of varying discrete wavelengths;
single-mode optical waveguide 604A and multi-mode optical waveguide
604B which may each include an optical fiber; an imaging probe 606
including optical elements comprising a diffraction grating 607A
for diffracting illuminating light 608A, a collimator 607B for
collimating the illuminating light, a focusing lens 607C for
focusing the illuminating light, and a coupler 607D for coupling
emitting light 608B to optical fiber 604B; a detection unit 610
which may be a single-element photo detector; a processing unit
612; and a display unit 614. Wavelength-swept light source 602;
optical waveguides 604A and 604B; imaging probe 606 including
diffraction grating 607A, collimator 607B, lens 607C, and coupler
607D; photo detector 610, processing unit 612, and display unit
614, may be similar to that shown in FIG. 5 at 502; 504A; 504B; 506
including 507A, 507B, 507C, and 507D; 510, 512, and 514.
[0085] System 600 is configured such that a proximal unit 601
includes light source 602, photo detector 610, processing unit 612,
and display unit 614 with imaging probe (distal unit) 606 distally
located. Connection of imaging probe 606 to proximal unit 601 is
through optical fibers 604A and 604B.
[0086] Reference is made to FIG. 7A which schematically illustrates
an exemplary single-event histogram from a cytometer, as known in
the art, and to FIG. 7B which schematically illustrates an
exemplary cross-sectional image along an x-axis and a y-axis of the
of a vessel acquired by any one of system 100-600 shown in FIGS.
1-6, in accordance with an embodiment of the present invention. The
single-event histogram shown in FIG. 7A is based on a use of a
single laser beam aimed at a hydrodynamically-focused stream of
fluid for counting particles one-by-one. From the cross-sectional
image shown in FIG. 7B, additional information on particles aside
from their number, such as for example, type, size, shape, location
in the vessel, color, brightness, and the like, may be readily
obtained. The additional information may be used to increase the
speed of measurement by increasing the flow rate, its accuracy, and
for the implementation of new cell collection systems that may use
this information for more efficient and accurate cell sorting.
[0087] Reference is made to FIG. 8 which illustrates a flow chart
of an exemplary method for acquiring an image of a particle in a
vessel, in accordance with an embodiment of the present invention.
Reference is also made to FIG. 1. It should be evident to a person
skilled in the art that the exemplary method described herein may
be implemented in other ways, forms, and/or manners, and is
therefore not intended to be limiting to the method described.
[0088] At 801, illumination light 108 is produced by light source
102 and sent over optical waveguide 104 to imaging probe 106 which
may include an endoscope or a catheter. Illumination light 108 may
be a broadband light or a wavelength-swept light. Optical waveguide
104 may be a single-mode optical fiber. Optionally, waveguide 104
may be a multi-mode optical fiber.
[0089] At 802, illumination light 108 is received by imaging probe
106 where the light is collimated by a collimator and spectrally
diffracted by a diffracted grating in optical element 107.
Optionally, illumination light 108 is not collimated.
[0090] At 803, a portion of vessel 116 is illuminated by
illumination light 108, the light spectrally dispersed along the
x-axis of the vessel.
[0091] At 804, particles 120-124, and optionally illuminated vessel
116 and/or body fluids 118, produce emitted light responsive to
being illuminated by illumination light 108. Imaging probe 106
collects (captures) the emitted light which is optically processed
by optical element 107 for sending through optical fiber 104 to
detection unit 110. Optionally, the emitted light may be sent to
reference arm 115 for creating an interference with a reference low
coherency light for obtaining axial information (along a z-axis) on
the illuminated particle 120-124 and/or illuminated vessel 116, for
reproduction of a 3D image. Optionally, the axial component of the
speed of the particle is determined.
[0092] At 805, emitted light is detected by detection unit 110.
Detection unit 110 may include a spectrometer for measuring a
distinct spectral band in the emitted light, a CCD camera for
capturing a single-shot image of the emitted light, a
single-element photo detector for measuring a discrete wavelength
of the emitted light, or any combination thereof. Detection unit
110 generates an output to processing unit 112 based on the
measurements.
[0093] At 806, processing unit 112 processes the output received
from detection unit 110 and reproduces the image of illuminated
particle 120-124 and/or illuminated vessel 116. Processing unit 112
performs all computations associated with flow cytometry, including
substantially simultaneous determination of a number of particles,
and other characteristics such as their type, size, shape, color,
brightness, and the like.
[0094] At 807, display unit 114 displays information from
processing unit 112. The information may be the 2D cross-sectional
image of illuminated particle 120-124, illuminated vessel 116, body
fluid 118, or any combination thereof, and optionally the 3D image.
Optionally, flow cytometry information computed by processing unit
112 is displayed.
[0095] It is expected that during the life of a patent maturing
from this application many relevant systems and/or methods will be
developed and the scope of the term system and/or method is
intended to include all such new technologies a prior.
[0096] As used herein the term "about" refers to .+-.10%.
[0097] The terms "comprises", "comprising", "includes",
"including", "having" and their conjugates mean "including but not
limited to". This term encompasses the terms "consisting of" and
"consisting essentially of".
[0098] The phrase "consisting essentially of" means that the
composition or method may include additional ingredients and/or
steps, but only if the additional ingredients and/or steps do not
materially alter the basic and novel characteristics of the claimed
composition or method.
[0099] As used herein, the singular form "a", "an" and "the"
include plural references unless the context clearly dictates
otherwise. For example, the term "a compound" or "at least one
compound" may include a plurality of compounds, including mixtures
thereof.
[0100] The word "exemplary" is used herein to mean "serving as an
example, instance or illustration". Any embodiment described as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other embodiments and/or to exclude the
incorporation of features from other embodiments.
[0101] The word "optionally" is used herein to mean "is provided in
some embodiments and not provided in other embodiments". Any
particular embodiment of the invention may include a plurality of
"optional" features unless such features conflict.
[0102] Throughout this application, various embodiments of this
invention may be presented in a range format. It should be
understood that the description in range format is merely for
convenience and brevity and should not be construed as an
inflexible limitation on the scope of the invention. Accordingly,
the description of a range should be considered to have
specifically disclosed all the possible subranges as well as
individual numerical values within that range. For example,
description of a range such as from 1 to 6 should be considered to
have specifically disclosed subranges such as from 1 to 3, from 1
to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as
well as individual numbers within that range, for example, 1, 2, 3,
4, 5, and 6. This applies regardless of the breadth of the
range.
[0103] Whenever a numerical range is indicated herein, it is meant
to include any cited numeral (fractional or integral) within the
indicated range. The phrases "ranging/ranges between" a first
indicate number and a second indicate number and "ranging/ranges
from" a first indicate number "to" a second indicate number are
used herein interchangeably and are meant to include the first and
second indicated numbers and all the fractional and integral
numerals therebetween.
[0104] As used herein the term "method" refers to manners, means,
techniques and procedures for accomplishing a given task including,
but not limited to, those manners, means, techniques and procedures
either known to, or readily developed from known manners, means,
techniques and procedures by practitioners of the chemical,
pharmacological, biological, biochemical and medical arts.
[0105] As used herein, the term "treating" includes abrogating,
substantially inhibiting, slowing or reversing the progression of a
condition, substantially ameliorating clinical or aesthetical
symptoms of a condition or substantially preventing the appearance
of clinical or aesthetical symptoms of a condition.
[0106] It is appreciated that certain features of the invention,
which are, for clarity, described in the context of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention, which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable subcombination
or as suitable in any other described embodiment of the invention.
Certain features described in the context of various embodiments
are not to be considered essential features of those embodiments,
unless the embodiment is inoperative without those elements.
[0107] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims.
[0108] All publications, patents and patent applications mentioned
in this specification are herein incorporated in their entirety by
reference into the specification, to the same extent as if each
individual publication, patent or patent application was
specifically and individually indicated to be incorporated herein
by reference. In addition, citation or identification of any
reference in this application shall not be construed as an
admission that such reference is available as prior art to the
present invention. To the extent that section headings are used,
they should not be construed as necessarily limiting.
* * * * *