U.S. patent number 6,021,344 [Application Number 08/984,391] was granted by the patent office on 2000-02-01 for fluorescence scope system for dermatologic diagnosis.
This patent grant is currently assigned to Derma Technologies, Inc.. Invention is credited to Harvey Lui, Calum E. MacAulay, David I. McLean, Branko Palcic, Haishan Zeng.
United States Patent |
6,021,344 |
Lui , et al. |
February 1, 2000 |
Fluorescence scope system for dermatologic diagnosis
Abstract
Apparatus for the diagnosis of a skin disease site by visual
fluorescence inspection comprising an excitation light source for
illuminating the disease site, a light guide for transmitting the
excitation light directly to the disease site to generate
fluorescence light and viewing goggles for processing the
excitation light reflected and the fluorescence light emitted from
the disease site to provide a fluorescence image of the disease
site to a user. The fluorescence image is used to aid the medical
assessment of skin conditions and the diagnosis of cutaneous
diseases by supplementing the visual assessment of skin lesions
made by the naked eye. The apparatus can be used in several modes
of operation that permit the viewing of full color fluorescence
images and enhanced two color images. The apparatus can also use
image intensifying equipment to amplify fluorescence light so that
even very weak fluorescing objects can be seen. A method for
acquiring and viewing the fluorescence images is also
disclosed.
Inventors: |
Lui; Harvey (Vancouver,
CA), Zeng; Haishan (Delta, CA), MacAulay;
Calum E. (Vancouver, CA), Palcic; Branko
(Vancouver, CA), McLean; David I. (Vancouver,
CA) |
Assignee: |
Derma Technologies, Inc.
(Vancouver, CA)
|
Family
ID: |
4159378 |
Appl.
No.: |
08/984,391 |
Filed: |
December 3, 1997 |
Foreign Application Priority Data
Current U.S.
Class: |
600/476;
351/159.3; 600/473 |
Current CPC
Class: |
A61B
5/0059 (20130101); A61B 5/0071 (20130101); A61B
5/444 (20130101); A61B 2090/502 (20160201) |
Current International
Class: |
A61B
5/00 (20060101); A61B 5/103 (20060101); A61B
19/00 (20060101); A61B 005/00 () |
Field of
Search: |
;600/476,473,475,477,478,310,317 ;351/163,165 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0113152 |
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Jul 1984 |
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EP |
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0783867 |
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Jul 1997 |
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EP |
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WO 94/16622 |
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Aug 1994 |
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WO |
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WO 96/08201 |
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Mar 1996 |
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WO |
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WO 96/36273 |
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Nov 1996 |
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WO |
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WO 96/39925 |
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Dec 1996 |
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WO |
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1997..
|
Primary Examiner: Kamm; William E.
Assistant Examiner: Shaw; Shawna J
Attorney, Agent or Firm: King; Joshua
Claims
We claim:
1. A binocular viewing apparatus comprising a frame adapted to be
worn on the head of a user, the frame comprising first and second
light filters fixedly mounted on either side of the frame, the
first filter positioned to transmit a first independent
fluorescence image to a first eye of the user and the second filter
positioned to transmit a second independent fluorescence image to a
second eye of the user, wherein each filter blocks at least light
having a wavelength of about 442 nm or less and each filter is a
band pass filter that passes the fluorescence light in at least two
different selected wavelength bands.
2. Apparatus as claimed in claim 1 in which the frame is an
eyeglass frame.
3. Apparatus as claimed in claim 1 in which the frame is a goggle
frame.
4. Apparatus as claimed in claim 1 in which the first and second
light filters comprise two identical light filters.
5. Apparatus as claimed in claim 1 in which the at least one filter
blocks light having a wavelength of less than about 475 nm.
6. Apparatus as claimed in claim 1 in which the at least two
selected wavelength bands are green light and red light.
7. Apparatus as claimed in claim 6 in which the green light is from
about 480 nm to about 560 nm and the red light is from about 620 nm
to about 700 nm.
8. Apparatus as claimed in claim 1 in which the apparatus further
comprises at least one image intensifier that intensifies the light
passing through at least one of the first and second light
filters.
9. Apparatus as claimed in claim 8 in which the apparatus further
comprises at least two image intensifiers, one for each of the
first and second light filters.
10. Apparatus as claimed 9 in which the first and second light
filters comprise first and second band pass filters, the first band
pass filter passing fluorescence light at a first wavelength band
to the first image intensifier and the second band pass filter
passing fluorescence light at a second wavelength band to the
second image intensifier.
11. Apparatus as claimed in claim 10 further comprising an adjuster
that adjusts the color of the fluorescence image transmitted to
each eye.
12. Apparatus as claimed in claim 11 in which the adjuster
comprises color filters located between the image intensifiers and
the eyes of the user.
13. Apparatus as claimed in claim 1 in which the apparatus further
comprises an excitation light source attached to the frame, the
excitation light source able to induce fluorescence in human skin
in front of the first and second light filters.
14. Apparatus as claimed in claim 13 in which the apparatus further
comprises a light guide that transmits the excitation light from
the excitation light source to the skin.
15. Apparatus as claimed in claim 14 in which the light guide
comprises an optic fiber having a microlens on an end of the fiber
located near the skin.
16. Apparatus as claimed in claim 15 in which the light guide
comprises an optic fiber bundle.
17. Apparatus as claimed in claim 15 in which the light guide
comprises a liquid light guide.
18. Apparatus as claimed in claim 13 in which the excitation light
source comprises a laser light source.
19. Apparatus as claimed in claim 13 in which the excitation light
source comprises an arc lamp selected from the group consisting of
a Mercury arc lamp, a Xenon arc lamp, and a metal halide lamp.
20. Apparatus as claimed in claim 13 in which the excitation light
source is selected from the group consisting of a LED panel and a
fluorescent UV lamp for direct illumination of the skin.
21. Apparatus as claimed in claim 13 in which the apparatus further
comprises at least one image intensifier that intensifies the light
passing through at least one of the first and second light
filters.
22. Apparatus as claimed in claim 21 in which the excitation light
source comprises a pulsed light source and the at least one image
intensifier acquires an image only when the pulsed light source is
activated.
23. Apparatus for diagnosis of skin disease sites by visual
fluorescence inspection comprising:
an excitation light source for providing excitation light for
illuminating the disease site;
means for transmitting the excitation light directly to the disease
site to generate fluorescence light; and
means for processing the excitation light reflected and the
fluorescence light emitted from the disease site to provide a
fluorescence image of the disease site to a user, wherein the means
for processing comprises first and second band pass filters, each
filter blocking the excitation light and passing the fluorescence
light in at least two different preselected wavelength bands,
wherein each filter is arranged in either side of binocular frames
to transmit an independent fluorescence image to each eye of the
user.
24. Apparatus as claimed in claim 23 in which the binocular frames
are eyeglass frames.
25. Apparatus as claimed in claim 23 in which the binocular frames
are goggle frames.
26. Apparatus as claimed in claim 23 in which the two or more light
filters comprise two identical light filters.
27. Apparatus as claimed in claim 23 in which the means for
processing the light includes image intensifying means associated
with the two or more light filters.
28. Apparatus as claimed in claim 27 further comprising an adjuster
that adjusts the color of the fluorescence image transmitted to
each eye.
29. Apparatus as claimed in claim 28 in which the adjuster
comprises color filters located between the image intensifiers and
the eyes of the user.
30. Apparatus as claimed in claim 23 in which the excitation light
source comprises a pulsed light source and the image intensifying
means acquires an image only when the pulsed light source is
activated.
31. Apparatus as claimed in any one of claims 1, 2 or 23 in which
the apparatus does not comprise an image intensifier.
32. A method of evaluating a potential human skin disease site by
visual inspection comprising the steps of:
illuminating the disease site with a excitation light under
conditions suitable and for a time sufficient to generate
fluorescence light in the skin disease site;
passing the fluorescence light through at least one band pass light
filter that passes the fluorescence light in at least two different
selected wavelength bands, the at least one filter mounted in a
binocular frame that is adapted to be disposed on the head of a
user, the at least one filter blocking at least light having a
wavelength of about 442 nm or less, thereby blocking the excitation
light reflected from the disease site and transmitting the
fluorescence light emitted from the disease site to at least one
eye of the user to provide a transmitted fluorescence image;
and
viewing and evaluating the transmitted fluorescence image.
33. A method as claimed in claim 32 in which the at least two
different wavelength bands are green light and red light.
34. A method as claimed in claim 33 in which the green light is
from about 480 nm to about 560 nm and the red light is from about
620 nm to about 700 nm.
35. A method as claimed in claim 32 in which the method does not
comprise passing the image that is transmitted to the eyes of the
user through an image intensifier.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority from Canadian Patent Application
No. 2,192,036, filed Dec. 4, 1996, which application is hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
This invention relates to a method and apparatus for viewing
fluorescence emissions from skin disease sites to assist in
diagnosis of the site.
BACKGROUND OF THE INVENTION
Currently, the clinical diagnosis of skin disease is generally
accomplished by visual inspection under white light illumination.
In this process, the reflectance pattern of a skin lesion is
examined. Visual diagnosis alone may not be particularly accurate
for the early detection of skin cancer since many skin conditions
have a similar appearance under white light. Therefore, when a
suspect lesion is identified by visual examination, a biopsy is
often performed for a definitive diagnosis. Not only is it crucial
to diagnose skin pre-cancer or cancer at its early stage when it is
curable, it is also important to improve the clinical diagnosis of
suspect skin lesions so as to avoid unnecessary skin biopsies.
Several approaches have been tried to improve dermatologic
diagnosis. Digital processing of reflectance images has been
intensively investigated recently. Although reflectance imaging has
led to improvements in registration, recording, and documentation
of skin lesions, there has been little improvement in the
diagnostic accuracy. The foregoing approach does not provide any
additional data to the physician making the visual assessment
because it is still based on the reflectance pattern of a lesion
under white light illumination which is essentially the same
pattern a human observer sees.
An alternative approach is ultraviolet UV or infrared IR
photography which extends the visual perception of a physician to
UV or IR reflectance patterns. However, the inconvenience due to
delays in film image processing renders this technique impractical
for everyday use.
A further alternative approach that is already in widespread
medical use involves a "Wood's lamp" which consists of a mercury
discharge lamp equipped with a filter that absorbs visible light,
and transmits UVA light with a 365 nanometer peak. When using this
device to assist in skin diagnosis, the eye serves as both the
detector and the long pass filter. The eye is not sensitive to UV
light, but is sensitive to visible fluorescent light. The "Wood's
lamp" must be used in a darkened room, where the physician can see
an image of a fluorescing disease site. The "Wood's lamp" is useful
for the diagnosis of skin conditions such as tinea capitis, tinea
versicolor erythrasma, and some pseudomonas infections, as well as
aiding in the detection and diagnosis of hypopigmented lesions.
SUMMARY OF THE INVENTION
The apparatus and method of the present invention permit viewing of
fluorescence emission images of skin to aid in the medical
assessment of skin conditions and the diagnosis of cutaneous
diseases by supplementing the visual assessment of skin lesions.
Effectively, the apparatus and method of the present invention
extend the vision of a physician to fluorescence images generated
by any preselected UV wavelength light or visible wavelength light
in order to assist in an accurate visual diagnosis.
Accordingly, the present invention provides apparatus for the
diagnosis of a skin disease site by visual inspection
comprising:
an excitation light source for illuminating the disease site;
means for transmitting the excitation light directly to the disease
site to generate fluorescence light;
means for processing the excitation light reflected and the
fluorescence light emitted from the disease site to provide a
fluorescence image of the disease site to a user.
Using the apparatus of the present invention, both full color
images and optically enhanced two color images over two specific
wavelength bands of a fluorescing site can be viewed by a
physician. An image intensifier version of the apparatus allows the
physician to view even very weakly fluorescing sites.
In a further aspect, the present invention provides a method of
diagnosing a skin disease site in low ambient light environment by
visual inspection comprising the steps of:
illuminating the disease site with a preselected excitation light
source to generate fluorescence light;
processing the excitation light reflected and the fluorescence
light emitted from the disease site to generate processed
fluorescence images; and
viewing and evaluating the processed fluorescence images to permit
visual diagnosis of the disease site.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the present invention are illustrated, merely by way of
example, in the accompanying drawings in which:
FIG. 1 is a schematic diagram showing an embodiment of the
apparatus of the present invention;
FIG. 2 is a detail view of an embodiment of the present invention
that uses spectacles;
FIG. 3 is a detail view of an alternative embodiment that uses
image intensifying means to enhance the fluorescence images
transmitted to the user; and
FIG. 4 is a table illustrating the visual appearance of three types
of skin lesions when viewed under normal white light and using the
apparatus and method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown a schematic block diagram of a
preferred embodiment of the apparatus of the present invention
useful for dark room diagnosis of a skin disease site 3 by visual
inspection. The apparatus includes an excitation light source 1 for
illuminating disease site 3 and a light guide 2 for transmitting
the excitation light directly to the disease site in order to
generate fluorescence light. The apparatus also includes means for
processing the reflected excitation light and the emitted
fluorescence light from the disease site in the form of binocular
viewing apparatus 4 adapted to be worn by a user such that
fluorescence images are transmitted to the user's eyes 5. The
foregoing apparatus is best operated under low ambient light
conditions so as to minimize interference with the relatively weak
fluorescence signals.
Light source 1 is selected to provide excitation light (either
ultraviolet or visible light) for the disease site. The excitation
light is conducted by light guide 2 to illuminate the skin at the
disease site of a patient. Endogenous fluorophores such as
tryptophan, collagen cross-links, collagen, elastin, NADH and
others in the illuminated skin tissue are excited by the photons of
the excitation light and emit fluorescence light. This fluorescence
light is processed by the binocular viewing apparatus 4 for viewing
by both eyes 5 of the user. The fluorescence emissions from the
skin are very sensitive to the composition and structural changes
of the tissue under examination. Different skin diseases or
different prognostic stages of one lesion may show different
composition and structural changes. Therefore, the cutaneous
fluorescence emissions that the apparatus of the present invention
permits to be observed provide more information about the skin
under examination than would reflected light pattern is under white
light. Thus, using the apparatus of the present application to
perform fluorescence examination of the disease site in combination
with conventional white light reflectance examination will permit
better diagnostic accuracy.
Light source 1 is selected to provide excitation light that will
generate tissue fluorescence. For example, a laser source such as a
helium-cadmium (He--Cd) laser provides 442 nm blue light that
generates fluorescence. Alternatively, a Mercury arc lamp light
source can be used which provides UV and visible light at specific
wavelengths, for example, a 365 nm UV line, a 405 nm blue line and
a 436 nm blue line. Other types of lamp light sources may be used,
such as a Wood's lamp, for illumination.
When a laser is used as a light source 1, light guide 2 is
preferably an optic fiber. It has been determined that a fiber with
a core diameter of about 400 .mu.m and a micro lens attached at the
fiber end adjacent the disease site works well as a light guide.
Laser light is easily focused into the fiber and the microlens
generates a uniform illumination spot. The diameter of the spot can
be varied by changing the distance between the microlens tip and
the skin surface.
If the light source is a Mercury arc lamp or other arc lamp such as
a Xenon or metal halide arc lamp, an optic fiber bundle or liquid
light guide of approximately 5 mm diameter is preferable as the
light guide since it is impractical to focus light from an arc lamp
into a single fiber. A 5 mm diameter fiber bundle or liquid light
guide is adequate to capture sufficient light from the source for
transmission to the disease site. A liquid light guide has better
transmittance than a fiber bundle and thus more light is
transmitted by a liquid light guide. However, this advantage is
offset by the greater expense of the liquid light guide. The
diameter of the light spot is varied in a similar manner as with
the optic fiber by varying the distance between the end of the
light guide and the skin surface.
Illumination may also be achieved without using a light guide. For
example, LED (light emitting diode) panels and UV fluorescent lamps
such as a Wood's lamp can be used to directly illuminate the
skin.
An example of a binocular viewing apparatus 4 is shown in FIG. 2
and comprises eye glass frames 20 with special light filters 6 and
7 mounted in either side of the frames to allow the transmission of
an independent fluorescence image to each eye of the user. In an
alternative arrangement, binocular viewing apparatus 4 comprises a
set of goggles (not shown) to house light filters 6 and 7. The eye
glass frames are preferably worn by users who do not normally wear
eye glass, while the goggles arrangement can be worn over a user's
conventional eye glasses.
There are a number of arrangements of light filters 6 and 7 in the
apparatus of the present invention.
In a first embodiment, filters 6 and 7 are identical long pass
filters selected to block the shorter wavelength excitation light
and pass the longer wavelength emitted fluorescence light for
viewing. In this manner, a full color fluorescence image of the
disease site is transmitted to the user. By way of example, if a
442 nm He--Cd laser is used as light source 1 for fluorescence
excitation, a 475 nm long pass filter (Scott glass GG475) can be
used as filters 6 and 7.
In a second embodiment, filters 6 and 7 are selected to provide an
enhanced two color image of the fluorescing disease site to the
eyes of the user. Filters 6 and 7 are two different band pass
filters, each filter being chosen to block the 'short wavelength
excitation light and pass longer wavelength fluorescence light with
set efficiencies for different wavelength bands to each eye.
Therefore, each eye 5 sees an image of the fluorescing disease site
in a color determined by the band pass filter in front of the
particular eye. In addition to being different colors, the two
images seen by the two eyes have different fluorescence intensity
distributions. It has been determined experimentally that the brain
of a user is able to compose the individual color images observed
by each eye to form a single two color image of the fluorescing
disease site that contains information in respect of the intensity
variation and the color variation of the disease site as compared
to the surrounding normal skin. The composed color at a particular
location in the image is determined by the ratio of the integral
fluorescence intensities over the two selected wavelength bands
passed by filters 6 and 7. Therefore, the composed image perceived
by the brain when using the apparatus of the present embodiment is
a two dimensional distribution of the fluorescence intensity and
the fluorescence ratio over two different wavelength bands. It is
an enhanced two color image of the fluorescing disease which
provides valuable information for skin disease diagnosis. Our
studies have shown that the wavelength bands of filters 6 and 7 can
be selected in response to fluorescence spectral studies of
diseased skin to provide characteristic two color images that
permit accurate diagnosis of a disease site condition.
In a third embodiment, filters 6 and 7 comprise two identical
customised band pass filters, each filter being designed to block
the excitation light and pass the emitted fluorescence light in at
least two preselected wavelength bands. The two wavelength bands
passed by filter 6 are identical to the two bands passed by filter
7 so that the viewing apparatus of the third embodiment permits the
examination of two color enhanced fluorescence images as described
above in relation to the second embodiment. The image perceived by
the brain using the customised identical filters of the present
embodiment is identical to the image perceived when using the two
different band pass filters of the second embodiment.
Although the binocular viewing apparatus 4 of the second and third
embodiments provide the same information regarding a disease site
under examination, each embodiment has its own advantages and
disadvantages. The different band pass filters 6 and 7 used in the
second embodiment are easy to design and make. The disadvantage
with using the two different band pass filters is that each eye is
shown a different image and some training is necessary for a user
to become comfortable with mentally combining the two different
images. This is similar to the training that is necessary in order
to view prepared photographs using special viewing glasses and be
able to perceive a three dimensional image. In contrast, the
disadvantage of using the same customised band pass filters in the
third embodiment is that the filters are more difficult to design
and manufacture and hence much more expensive. However, using a
viewing apparatus fitted with the customised filters requires no
special training as the same two color image is transmitted to each
eye. Both eyes see both wavelength bands, and, therefore, the
brightness of the perceived image will be approximately twice that
perceived using the viewing apparatus of the second embodiment
where each eye sees only one of the two wavelength bands.
FIG. 3 is a schematic view of a further embodiment of the present
invention involving another variation in the viewing apparatus 4.
In this case, the viewing apparatus is provided with image
intensifying means associated with the light filters comprising
image intensifier 10 and 11. The principle of operation is the same
as with the second embodiment of the viewing apparatus except that
image intensifiers 10 and 11 are used to amplify the fluorescence
light so that very faint fluorescing disease sites can be
viewed.
The intensified viewing apparatus comprises a pair of tubular
housings mounted in a binocular frame for presenting simultaneous
images to each eye. Each tubular housing comprises a band pass
filter 6 or 7, a first lens 8 or 9, an image intensifier 10 or 11,
a second lens 12 or 13 and a final filter 14 or 15. Fluorescence
light from the disease site is filtered by filters 6 or 7 which are
preferably two different band pass filters. The filtered
fluorescence light is then focused by lens 8 or 9 to form an image
on the photocathode of the image intensifier 10 or 11. As is
conventional, the photocathode converts photons into electrons. The
number of electrons corresponding to each image pixel is then
multiplied by a multi-channel microplate with high voltages at its
two ends. The multiplied electrons exit from the microplate and
collide with a phosphor screen to form an optical image again. Lens
12 or 13 focuses the images for transmittal to the eye. Filter 14
or 15 provides a means to adjust the color of the image presented
to the eye. In combination with filter 14 or 15, different colored
phosphors can be used in each of the phosphor screens of the image
intensifiers 10 or 11 to create different colored images that are
presented to each eye. In this manner, an optically enhanced two
color image of the fluorescing disease site is presented to the two
eyes of the user. As described previously, the two images are
composed by the brain and perceived as a two dimensional
distribution of the fluorescing intensity and the fluorescence
ration over two different wavelength bands.
In association with the intensified viewing apparatus, light source
1 can be a pulsed source (flash lamp or pulsed laser), and
intensifiers 10 and 11 can be gated to acquire images only when the
skin is being exposed to the light pulses. An intense pulse light
source with pulse width in the microsecond to nanosecond domain
will generate cutaneous fluorescence that is much brighter than the
ambient light. The image intensifiers are gated on during this
period to acquire the fluorescence image. Outside of the pulse
duration, the intensifiers are gated off, and the ambient reflected
light images are not acquired. In this way, the cutaneous
fluorescence images can be viewed with the ambient light on.
In order to demonstrate the use of the apparatus and method of the
present invention, FIG. 4 is provided. FIG. 4 is a table showing in
columns the visual appearance of three types of skin conditions,
seborrheic keratosis, compound nevus and basal cell carcinoma, when
viewed under different light. Each row of the table shows the skin
conditions under a different light condition.
The first row is the reflectance images under white light of the
three skin sites. These images show substantially what a physician
sees with the naked eye. All three skin conditions can appear
substantially the same: a reddish, brown area surrounded by
generally white skin. Distinguishing between the various conditions
is sometimes difficult.
Row 2 and 3 show the appearance of the skin lesions and their
surrounding skin when view using 442 nm He--Cd laser excited
fluorescence light. It is apparent that the coloring of the various
lesions tends to be distinctive which greatly aids a user in
differential diagnosis of the three different lesions.
Row 4 of FIG. 4 shows the fluorescence spectra, fluorescence
wavelength plotted against fluorescence intensity, for the disease
sites illuminated by the 442 nm He--Cd laser.
Row 2 contains full color fluorescence images of the sites using
the apparatus of the first embodiment of the present invention
where filters 6 and 7 are identical 475 nm long pass filters. The
full color fluorescence images all have a yellowish background
(normal skin). The seborrheic keratosis looks bright yellow since
its spectrum has a higher intensity surrounding normal skin (see
row 4). Both the compound nevus and bagel cell carcinoma look
darker than the surrounding skin since their spectra have lower
intensities than the surrounding skin. Therefore, the full color
fluorescence images are useful for differentiating the seborrheic
keratosis from the other two lesions.
In row 3, the images are optically enhanced two color images
acquired using the apparatus of the second or third embodiments or
the image intensified apparatus. In this particular example, the
two wavelength bands selected are green (480 nm to 560 nm) and red
(620 nm to 700 nm). The two color images have a greenish background
identifying normal skin. The seborrheic keratosis looks bright
green since its spectrum has higher intensities in the green band
than surrounding normal skin. The transmittance of the two
wavelength bands are selected so that the basal cell carcinoma
looks reddish, the compound nevus looks dark grey and normal skin
appears greenish. This is due to the fact that the ratio of the
spectral maximum intensity of normal skin to that of the compound
nevus is 4 while the ratio for basal cell carcinoma is 3.
The images of FIG. 4 are only a few examples of the differential
diagnosis capabilities of the apparatus and method of the present
invention which provide new information for skin diagnosis.
The present invention provides a number of important technical
advantages that can be summarised as follows:
1. The apparatus of the present invention provides new information
for skin diagnosis as compared to conventional white light
examination.
2. In comparison to a Wood's lamp, different excitation wavelengths
including visible light can be used for fluorescence examination.
The enhanced two color fluorescence examination mode is a totally
different mode than Wood's lamp, and it enhances the color ratio
over two wavelength bands to provide more powerful discrimination
capabilities.
3. The image intensified embodiment of the present invention allows
very weak fluorescing disease sites to be view and diagnosed.
4. The apparatus of the present invention are relatively
inexpensive and easy to use.
5. The apparatus and method of the present invention provides a
new, non-invasive system for performing more accurate dermatologic
diagnosis.
Although the present invention has been described in some detail by
way of example for purposes of clarity and understanding, it will
be apparent that certain changes and modifications may be practiced
within the scope of the appended claims.
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