WO1994016622A1

WO1994016622A1 - Diagnostic imaging method and device

Info

Publication number: WO1994016622A1
Application number: PCT/US1994/000702
Authority: WO
Inventors: Yoram Tsivion; Menashe Shachar
Original assignee: Computer Aided Medical U.S.A. Inc.
Priority date: 1993-01-19
Filing date: 1994-01-19
Publication date: 1994-08-04
Also published as: IL108350A0; ZA94343B; AU6230994A

Abstract

The present invention relates to the field of diagnostic imaging devices for the primary care physician and general practitioner. The apparatus and method of the present invention produces a diagnostic image by exposing the live tissue specimen in situ to a primary light; selecting particular wavelengths of secondary light returned from the examined tissue; and obtaining one or more sequential images of the examined tissue. The image is displayed so that abnormal tissue may be differentiated from healthy tissue by visual inspection of the display.

Description

DIAGNOSTIC IMAGING METHOD AND DEVICE

This application is a continuation-in-part of U.S. Serial No. 08/004,894, filed January 19, 1993, now pending. FIELD OF THE INVENTION The present invention relates to diagnostic imaging devices, primarily for use by a primary care physician or general practitioner.

Primary care physicians presently rely on relatively unsophisticated and inconsistent technology to diagnose, distinguish, and stage abnormal tissue types, including diseased and particularly malignant tissue types. Currently, the non-specialist physician typically performs diagnostics with only an ordinary source of light, the physician's visual perception, and the physician's expertise in tissue morphology identification.

The present invention provides a relatively consistent and discriminating diagnostic method which utilizes specially selected frequencies of light to highlight factors typically observed in evaluating abnormalities or diseases such as malignancies. These factors include the darkness of the lesion, the regularity of its outline, and the variability or texture of its appearance.

BACKGROUND OF THE INVENTION

Typical unaided visual examination of tissue specimens is of limited effectiveness and reliability because of the limited capability of unaided human vision to perceive the different wavelengths that comprise sensed light such as those wavelengths of light returned from the specimen. For instance, this may result in the mistaken perception of a light as a specific color even though that light includes different radiant energy inputs each having distinct spectral frequencies or wavelengths. Thus, a physician may conclude that two distinct tissue types are indistinguishable because they appear to be the same "color" to his eye, while in actuality, the "color" of each tissue is spectrally distinct. This, in turn, may result in an erroneous diagnosis.

Another limitation of traditional methods of observation is that the radiant energy that is received by the physician's eye, including radiant energy of the wavelengths from which different tissue types could be visually differentiated, may be diluted or, in effect, partially masked by ambient radiant energy of other wavelengths under normal examination conditions. This may result in the perception of an indistinct image by the physician, thereby increasing the possibility of misdiagnosis.

Furthermore, the greater the amount of light directed to an examiner's eye, the more the iris of the examining physician's eye will contract. If this light includes non-informative wavelength components, the amount of the significant light components that may enter the eye may be diminished. This may result in a less distinct perception of the observed tissue and misdiagnoses.

Additionally, human memory is unreliable in its recollection over time of different color hues and intensities. Human vision perception (including color) may also be affected by environmental factors. Thus, an erroneous recollection of the exact color of a particular malignancy for comparison purposes may also result in adverse medical consequences. Kenet et al., U.S. Patent No. 5,016,173, broadly discloses in vivo monitoring of visually accessible body surfaces by stimulating the surface with light and analyzing the images of reflected or emitted light. However, Kenet et al. does not recognize any advantages achieved by specific illumination wavelengths or by imaging specific wavelengths of returned light. The present invention overcomes the drawbacks of these examination techniques by illuminating a specimen suspected of containing a lesion, with primary radiant energy of a desired wavelength or range of wavelengths without causing undue stress to the tissue, selecting the wavelengths or range of wavelengths of secondary radiant energy returned from the specimen at which a particular tissue type can be differentiated from the surrounding tissue environment, and displaying an image derived from one or more of the selected component (s) of secondary light from which the physician can discern the nature of the examined tissue. This information and any output image can be stored for record and comparison purposes or can be transmitted to remote viewing stations, thereby facilitating consultations or specialist reviews. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a primary care physician with a diagnostic device to facilitate the detection of abnormal tissue in situ.

Another object is to provide an imaging diagnostic device by which abnormal tissue can be more readily identified by visual means.

A further object of the invention is to provide a resulting diagnostic image of the examined specimen within a short time period. In accordance with the present invention, there is provided a method for analyzing tissue by

(a) exposing a tissue suspected of including a lesion having (i) darkness, (ii) outline, (iii) texture, (iv) other morphological features or (v) any combination thereof, to a primary light comprising at least one spectral component of white light, to yield a secondary light from the tissue, the secondary light being comprised of at least one wavelength component, and the wavelengths of the secondary light being the same as or different from those of the primary light;

(b) selecting at least one component of the secondary light selected from the group consisting of (i) those having a wavelength at least as long as the wavelength of red light and (ii) those having a wavelength at least as long as the wavelength of green light; and

(c) displaying an image of the lesion derived from the selected secondary light components, whereby the lesion is capable of being distinguished from normal tissue due to a difference between the lesion and normal tissue as to (i) darkness, (ii) outline, (iii) texture, (iv) other morphological features, or (v) any combination thereof. In a further contemplated embodiment, the suspect tissue is exposed to an ultraviolet primary light, this light being comprised of at least one wavelength component, to yield a secondary light from the tissue. At least one component of the secondary light having a wavelength at least as long as the wavelength of green light is selected, and an image of the lesion derived from the selected secondary light components is displayed.

Preferably, these methods are non-invasive, and the lesion to be detected is a skin or a cervical lesion. Alternatively, the selected components can be digitized before imaging.

In another contemplated embodiment, an apparatus for analyzing tissue illuminated by a primary light is provided. The apparatus comprises (a) a primary light source, (b) a filter for selecting at least one component of the secondary light from the tissue in a band of wavelengths correlated to the type of tissue and type of lesions suspected, and finally (c) a display device for displaying a visual image derived from selected secondary light. An optional image receiving device for producing separate digitized data representing a digitized image of the selected component (s) , and means for processing the digital data to produce digitized images of red, green, and blue components of the selected component(s) can be incorporated, and the visual image can be derived from one or more of the red, green, or blue selected components. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of an imaging device according to the invention.

Figure 2 is a block diagram of another form of imaging device incorporating a filter wheel. Figure 3 is a block diagram of a further form of imaging device incorporating a beam splitter. DETAILED DESCRIPTION OF THE INVENTION

Abnormal or diseased tissues, including, but not limited to, malignant tissues, can be visually distinguished from normal tissues by their preferential absorption, reflection, emittance, and/or fluorescence of radiant energies having particular electromagnetic frequencies or wavelengths. A particular abnormal tissue or lesion may completely, or to a certain extent, absorb, reflect, emit, or fluoresce radiant energy of a specific wavelength while a different type of lesion or normal tissue may do so to a different extent or not at all. For example, it has been discovered that healthy skin tissue can be visually differentiated from deviant skin tissue when examined under red light, while healthy cervix tissue is visually distinguishable from unhealthy tissue when observed under green light.

The methods and apparatus of the present invention can be used to analyze any tissues. However, the methods of the present invention are particularly well suited for non- invasive use where a primary light can most easily be directed to the tissue suspected of including a lesion. Suitable tissues include, but are not limited to, skin tissues and cervical tissues, and diagnosable lesions include, but are not limited to, malignant lesions. The present invention can also be used in an invasive procedure to analyze tissues such as cardiac tissue and the like during operations or in invasive or non-invasive biopsies.

In the methods of the present invention, a tissue or a specimen suspected of including a lesion is exposed, and preferably illuminated, by a source of primary light.

The primary light source may be a white light source such as ambient light, incandescent lights, discharge lamps such as an electronic camera flash, or spotlights. Alternatively, the primary light source may be an ultraviolet light source. Preferably, the ultraviolet light emitted from the primary light source is ultraviolet light in the UV-A region, which is also known as long wave UV, near UV or black light. This region includes light of wavelengths ranging from about 320 nm to about 400 nm. Preferably, the primary light source generates radiant energy of a sufficient intensity at the particular wavelengths being used to facilitate a high signal-to-noise ratio. However, the intensity of the radiation should not be so high as to harm a live specimen, such as the skin or other exposed area of a person. Examples of such harmful radiation include, but are not limited, to short wavelength ultra-violet light such as the UV-C region.

Secondary light is returned or emanates from the tissue that is exposed to the primary light, by reflection, emission, fluorescence, or any combination thereof. One or more wavelength components of the secondary light returned from the exposed or illuminated specimen are selected, preferentially by passing the secondary light through a selecting device which permits only specific light wavelengths or ranges of wavelengths to pass, and an image of the lesion is derived from the selected secondary light.

The selection of the desired component of the secondary light or radiant energy may be accomplished by any known means for the selective transmission of light. These may include filters, including, but not limited to, polarizing light filters, color filters, staining, etc. Special mention is made of a selection means that utilizes a color wheel having filters located about its perimeter or of a prism.

The selected secondary light is not limited to a single wavelength in the electromagnetic spectrum. Bands of wavelengths corresponding to a particular region of the electromagnetic spectrum may yield desirable results. For example, when the primary light is white light, the preferred range of wavelengths of secondary light for the visualization of several skin tissue types corresponds to the red region, i.e. those radiant energies having wavelengths at least as long as that of red light of the visible spectrum or about 610 nm or greater. Therefore, preferred selecting means for use in examination of skin tissue with primary white light would include, for example, a red light passing filter such as Schott Models OG570, RG610, or RG630 filter which pass a band of light of wavelengths greater than about 570 nm, 610 nm or 630 nm respectively. A red narrow pass band filter would additionally minimize those components having wavelengths sufficiently shorter than red light, such as blue and violet components.

Similarly, when the primary light is white light, the green, yellow and orange regions of the secondary light, i.e. those radiant energies having wavelengths at least as long as that of green light or about 520 to about 570 nm, is preferred for the analysis of cervical tissue. Therefore, preferred selecting means for use in examination of cervical tissue with primary white light would include, for example, green light passing filters such as Schott filters GG435, GG495, and green narrow band filters.

Although all of the secondary light may be selected when an ultraviolet or near ultraviolet primary light is used, preferred selecting means for use in examination of tissue and particularly skin tissue with primary ultraviolet or near ultraviolet light include, for example, a green light passing filter as described above, and particularly those such as a Schott OG570 which passes wavelengths greater than about 570 nm. A high pass or a band pass filter that cuts off below or within the green region would additionally minimize those components having wavelengths significantly shorter than green light, such as blue and violet components.

It should be noted that when a filter is used as a selecting means, it is recognized that the filter may not completely block all of the components having a non-selected wavelength. It is only necessary that a sufficient amount of non-selected components are blocked so that the non- selected components do not interfere with the image. For example, a typical 3 millimeters thick OG570 green filter will allow 46% of the light having a wavelength of 570 nm to pass, 9% of the light having a wavelength of 560 nm to pass, 4x10^% of light having a wavelength of 550 nm to pass, and lxl0^"5% of the light having a wavelength of 360 nm to pass.

Two or more separate filters may be used together or sequentially as well. A rotatable filter wheel can be incorporated. The wheel carries a plurality of filter sectors, each separately and selectively interposable between the specimen and the following light sensor. By rapid rotation of filter wheel, the successive images will represent the exact same specimen area, substantially at the same instant and in the same condition, permitting a comparison of two or more images derived from two different types of secondary light taken through different zones of the filter wheel.

In an alternate embodiment, the primary light source may be limited to only the desired secondary light wavelength bands and the selecting device can be eliminated or a selecting device, such as for example a prism, may be interposed between the primary light source and the specimen. However, the method whereby the secondary light components are selected is more desirable to provide higher signal-to-noise values and to inhibit variable effects of ambient light. Additionally, it should be noted that in comparing the different spectral qualities of the specimen, it is of course desirable that the different spectral versions correspond to the same geometric area or posture of the subject. For example, the light from the illuminated specimen may pass to a conventional optical beam splitter which divides the image into several beams. Each beam then passes through a respective filter.

However, selection of the specific desired wave band component of the secondary light is preferably made near the point where the radiant energy is imaged or digitized.

The secondary light is received by a light sensing or an image capture device to provide an image, which may be of the lesion, from the selected components of the secondary light. Preferably, the image is in digital form, i.e. a digitized image. The image derived from the selected secondary light component(s) is displayed either directly or indirectly, and is displayed immediately or is stored. The display is derived from secondary light components that are either imaged, imaged and digitized, or digitized and imaged. Typically, the selected secondary light will be imaged on a photographic film such as, for example Fuji 400 film. By examining the displayed image, the physician may note the darkness or gray level of the suspected lesion, irregularities of its outline, and/or the texture or variability of its surface, all of which are indicative of possible malignancy or disease. In particular, abnormal tissues or lesions exhibit non-uniform surfaces, irregular outlines, or abrupt changes in the image intensity of certain areas relative to other areas.

If the selected radiant energy is to be digitized, it is converted into digital format by suitable light sensing and digitizing means. It will be understood that by a "digitized image" is meant a representation of the specimen in the form of a matrix of pixels (e.g., 1800 pixels wide by 1200 pixels high) , where each pixel is represented by a binary number which includes data as to the position of the pixel in the image and at least one intensity value (e.g., 8 bits to provide 256 gray levels). The necessary functions entail sensing the pattern of different light intensities within a given area at a specific time and converting that pattern into a "digitized image" by assigning for each point of the area (pixel) a digital (preferably binary) value corresponding to the light intensity received from that particular image point at the specified time.

For example, the photograph, illuminated under normal conditions, can be scanned by a conventional digitizing scanner (such as Scanmaster produced by Microtek Inc.) which provides a digitized image of the photograph, as a matrix array of pixels, each pixel being constituted by digital data defining its position in the matrix array, and additional data representing the filtered light intensity of the individual pixel. If a filter wheel or other sequential secondary light output manipulator is used, each filtered output can be supplied to an electronic light sensor connected to respective conventional frame grabbers or image digitizers synchronized to the position of the wheel to provide respective filtered digitized images of the specimen, for subsequent processing. Each of these images may be processed and displayed by an appropriate computerized processor as described above or with another multi-spectral analyzer. Frame grabbers may be used in conjunction with video or high definition video cameras to provide the digitized images.

In one embodiment of the invention, the digitized radiant energy image is converted into a diagnostic image for viewing by utilizing a multi-spectral image-processing algorithm that can normalize the data and separate the data corresponding to pertinent tissue features. Generally, one form of multispectral image processing algorithm operates by comparing two different digitized images of the same subject matter, derived by sensing different spectral components of the same object. In another embodiment, a digitized image of one color component (such as red) is compared to the digitized image of another color component (such as blue) or to an unfiltered version of the same specimen region.

The algorithm derives from the respective pixels at each pixel position, a resultant pixel value. The matrix of such resultant pixel values forms a diagnostic image whereby different tissue types may be visually distinguished. The preferred means to process the digitized data into an output image utilizes a desktop computer running software incorporating multi-spectral image processing algorithms. A preferred means to carry out the digitizing of the selected radiant energy is a digital image sensor or video camera coupled to a digitizer, such as a conventional electronic or video camera.

One suitable digitizing image capture device is a Kodak Professional DC 200 Digital Camera having a conventional Nikon camera body and optics incorporating a CCD image sensor and memory, or other electronic camera using an Eastman Kodak KAF-4200 chip such as Photometric Series 200 which interfaces directly with a PC. Such a device provides a digitized image of the specimen, suitable for further processing and display.

A digital electronic camera provides a signal for each pixel, which signal includes separate data for the usual three primary color (red, green, blue) components of the light at that pixel position. For example, the digitized pixel signal may have 24 bits devoted to pixel value, with 8 bits for the red component and 8 bits for the green component level and 8 bits for the blue component level. As a further wavelength-restricting process, the data processing software may be used to pass only bits representing the desired color component, for example, red or green, thereby restricting the displayed image to only the desired color component. That image is then processed in a light data processor, and is supplied to a display device to provide the examining physician with an image for interpretation. In an alternative arrangement, the image capture device may be a video or high definition television camera, in association with a conventional frame grabber circuit to provide the desired digital representation of the restricted-light-band image of the tissue specimen. The resultant image may be displayed by means of a suitable conventional computer peripheral image device, such as a CRT monitor, printer, video screen, etc. Delays in developing and scanning photographs are avoided in a system that provides a substantially immediate display. The preferred means for displaying the digitized output image is a CRT monitor which may be monochrome or polychrome. The digitized image data and the resultant output image may be stored by means of any conventional digital data storage device such as a computer hard disk, a magnetic tape, or an optical disk.

The data processor may have conventional image processing means for aiding examination (such as brightening and/or magnification) of selected areas of the input image. PhotoStyler desktop software of U-lead Systems Inc. may be used with a computer, such as a 486 processor based PC with adequate memory. The output of the processor is made visually accessible to the physician by the display device which may be a conventional black and white monitor or a personal computer. A display device of at least 1024x1024 pixels is preferred.

A multi-spectral analysis of two or more of these different digitized images will provide more significant displayed images for diagnosis. By way of example, a separate digitized image matrix may be obtained for each of two different filter bands. Then, by conventional algorithms, the intensity value of each pixel from one image is compared in the data processor 9 with the intensity value of the correspondingly located pixel of the other image, to provide a composite value (e.g. a ratio of intensities) . These composite values may then be displayed by false-color imaging on a color monitor or computer (rather than a monochrome display) to yield color patterns indicative of malignancy or disease distinguishable from similar patterns for healthy tissue.

In one such arrangement, if the ratio is less than a fixed value (such as one) , the displayed pixel is given one color (e.g. green) while if the ratio is greater than the fixed value, the displayed pixel is given a distinctive color (e.g. red) . The resulting displayed pattern (like a bit map) may be compared with similar patterns for known malignancies or healthy tissue to provide diagnosis of possible malignancy or disease.

As an alternate procedure, a color-restricted digitized image of a specimen may be compared by such multispectral analysis with a concurrent non-color- restricted image of the same tissue specimen, to reduce or eliminate factors which may tend to distort data derived from ambient-illuminated skin or tissue. This permits comparing a selected specimen area with adjoining or background areas, to distinguish them as to malignancy or abnormality. Apparatus for practicing the invention are illustrated in Figures 1-3. In Figure 1, the specimen 3 is exposed to the primary light source 1. Secondary light from the specimen 3 passes through the filtering device 5 and to the image capturing device 7. The image from the image capturing device 7 is received by a digital data processor 9 and is displayed by the display device 11 or is recorded by the recording device 13.

Figure 2 illustrates the use of a color wheel having a plurality of filter segments 17, each of appropriate light-transmitting characteristics. Secondary light from the specimen 3 passes through the revolving color wheel segments 17. The light data transmitted through each segment of the filter wheel is supplied to respective conventional frame grabbers FG 1-5, which provide respectively filtered digitized images of the specimen 3. Each frame grabber data may be passed to a multi-spectral analyzer for processing and display as described above.

Figure 3 illustrates the incorporation of a beam splitter 19 in place of the color wheel. Secondary light from the specimen 3 passes through the beam splitter 19. The light components transmitted by the beam splitter 19 are passed through respective filters 21a-c, and the filtered light is passed to a digitizing data processing and display device as described above.

The apparatus of the present invention can be used under normal light conditions. It includes a primary light source, means for selecting particular wavelengths of light reflected or secondary light from the examined tissue, such as by using light filters that transmit the desired range of light wavelengths; means for obtaining one or more sequential images of the examined tissue, each taken under different light wavelengths, in rapid sequence so that the multiple images are, for the practical purposes of this invention, equivalent as to space and time, such as by a color light filter wheel attachment on an electronic image sensor; means for converting the various light intensities derived from the specimen into a digital form in a specified format, preferably utilizing an electronic image sensor or capture device; means for processing the digital information according to an appropriate image processing algorithm, preferably utilizing a computer with appropriate software; means for storing the processed results in an image memory device, preferably utilizing computer memory; and means for displaying the resulting output image, whereby abnormal diseased or cancerous tissue may be differentiated from healthy tissue by ordinary visual inspection of the display, preferably using a conventional computer peripheral display. Imaging devices include, but are not limited to an image capturing device (camera) for a color-restricted image, an image digitizing device, an image-processing device and a display device, and which enhance the details of tissue under examination by computerized color separation, to provide a diagnostic aid suitable for primary care physicians.

The present invention thereby provides an apparatus and methods for the non-invasive screening of body surface tissues to aid in determination of malignancies and other abnormalities, suitable for use by primary care physicians and general practitioners. DESCRIPTION OF ILLUSTRATIVE EXAMPLES Example 1

A suspected cheek skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be a dysplastic pig ented lesion.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

Outline of the lesion was determined to be very regular. Visible darkness of the lesion was determined to be dark. Texture of the lesion was determined to be variable.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. However, secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was determined to be slightly visible in parts.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as dark- variable.

Finally, the skin lesion was analyzed by again exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was filtered through a Schott OG570 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Image tone was observed as dark-regular.

Loose follow-up was proposed as case management, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses correctly indicated that tissue excision was unnecessary. Results are illustrated in Table 1.

Example 2

A suspected back skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be dysplastic.

Outline of the lesion was determined to be irregular. Visible darkness of the lesion was determined to be dark. Texture of the lesion was determined to be variable. The skin lesion was also analyzed by exposing, in situ, the suspect tissue to primary white light from the same source. However, secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not readily visible. The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a

Minolta X-700 camera. Image tone was observed as medium- dark.

Removal of the lesion was proposed as case management, and subsequent pathological studies identified the lesion as a junctional lesion. The light analyses incorrectly indicated that tissue excision was desirable. Results are illustrated in Table 1. Example 3

A suspected neck skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of a pigmented lesion was made.

Outline of the lesion was determined to be rather regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be variable.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. However, secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as light.

Loose follow-up was proposed as case management, and subsequent pathological studies identified the lesion as BCC. The light analyses correctly dismissed the possibility of malignant melanoma in this case. BCC's, although considered to be very mold cancers, are however, treated by excision. Results are illustrated in Table 1. Example 4 A suspected back skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be Bowen's disease.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electronic flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

Outline of the lesion was determined to be irregular. Visible darkness of the lesion was determined to be light. Texture of the lesion was determined to be even.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as light and peculiarly shaped.

The lesion was not a malignant melanoma, and subsequent pathological studies identified the lesion as a crust with formation and fibroblastic proliferation of the upper dermis. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 5

A suspected scalp skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of seborrheic keratosis was made. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be slightly irregular. Visible darkness of the lesion was determined to be very dark. Texture of the lesion was determined to be variable.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was visible in parts.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a

Minolta X-700 camera. Image tone was observed as dark- variable.

Finally, the skin lesion was analyzed by again exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was filtered through a Schott OG570 filter. and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Image tone was observed as very dark.

It was proposed to remove the suspected malignant melanoma, and subsequent pathological studies identified the lesion as pigmented BCC. The light analyses correctly indicated that the tissue should be excised although the lesion was not a melanoma.

Results are illustrated in Table 1. Example 6

A suspected umbilical region skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be an umbilical region papillary pigmented nevus.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be very regular. Visible darkness of the lesion was determined to be light. Texture of the lesion was determined to be even.

The skin lesion was also analyzed by again exposing, n situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

Minolta X-700 camera. The lesion disappeared on the image. The lesion was evaluated as harmless, and subsequent pathological studies identified the lesion as a compound lesion.

Results are illustrated in Table 1. Example 7

A suspected cheek skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of a pigmented lesion was made. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be variable.

Minolta X-700 camera. Image tone was observed as medium.

Loose follow-up was the proposed case management, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 8

A suspected abdominal skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of a blue lesion was made.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be dark in the center and lighter elsewhere.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was determined to be visible in the center.

Minolta X-700 camera. Image tone was observed as very dark. Removal was proposed, and subsequent pathological studies identified the lesion as a junctional dysplastic lesion. Results are illustrated in Table 1.

Example 9

A suspected neck skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of a suspicious recent growth nevus was made.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be light.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible. The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as light.

The lesion was believed to be harmless and subsequent pathological studies identified the lesion as an intradermal lesion. The light analyses correctly indicated that tissue excision was unnecessary. Results are illustrated in Table 1.

Example 10

A suspected back skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be a dysplastic, pigmented lesion.

Outline of the lesion was determined to be irregular. Visible darkness of the lesion was determined to be dark. Texture of the lesion was determined to be variable.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was visible in parts . The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as medium.

Finally, the skin lesion was analyzed by again exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was filtered through a Schott OG570 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Image tone was observed as medium.

Removal was proposed, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses incorrectly indicated that tissue excision was desirable.

Results are illustrated in Table 1. Example 11 A suspected thigh skin lesion was evaluated, in situ, by a skill practitioner by unaided visual observation under ambient light. The lesion was observed to be dysplastic.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash/ambient light source. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be even.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was nearly invisible.

Minolta X-700 camera. Image tone was observed as medium.

Outline was observed as regular. The lesion was believed harmless, and subsequent pathological studies identified the lesion as an intradermal lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 12

A suspected elbow skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of a changing pigmented lesion was made. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Visible darkness of the lesion was determined to be dark. Texture of the lesion was determined to be variable. The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Outline was observed as irregular. Finally, the skin lesion was analyzed by again exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was filtered through a Schott OG570 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Image tone was observed as very dark.

Removal of the suspected malignant melanoma was proposed as case management, and subsequent pathological studies identified the lesion as lentigo maligna. Results are illustrated in Table 1.

Example 13

A suspected ear skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be a non-malignant nevus. The lesion had changed rapidly and was bleeding.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be almost regular. Visible darkness of the lesion was determined to be light. Texture of the lesion was determined to be even. The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

Minolta X-700 camera. Image tone was observed as not dark.

The lesion was believed to be harmless, papilla or intradermal nevus and subsequent pathological studies identified the lesion as an intradermal lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 14

A suspected abdominal skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The patient was a multiple lesion case, and the most suspicious specimen was studied. The lesion was observed to be a dysplastic pigmented lesion. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be dark. Texture of the lesion was determined to be variable. The skin lesion was also analyzed by exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was visible.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as dark/medium.

Finally, the skin lesion was analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm. The secondary light returned from the tissue was filtered through a Schott OG570 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Image tone was observed as dark medium.

Removal of the most suspicious specimen was proposed as case management, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses incorrectly indicated that tissue excision was desirable.

Results are illustrated in Table l. Example 15

A suspected back skin lesion was evaluated, in situ, by a dermatologist or a plastic surgeon by unaided visual observation under ambient light. The back lesion was observed to be dysplastic.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be even.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was barely visible.

Loose follow-up was proposed as case management, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 16

A suspected abdominal skin lesion was evaluated, in situ, by a skilled practitioner by marked visual observation under ambient light. A clinical diagnosis of a pigmented lesion was made. The lesion had been stable for several years.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash/ambient light source. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be variable.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was visible. The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as dark- medium. Outline regularity was observed as variable.

Example 17

A suspected forearm skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be a keratosis or a malignant melanoma. The patient was stable.

Outline of the lesion was determined to be irregular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be variable.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as medium- dark.

The lesion was then believed to be non-malignant and loose follow-up was proposed as case management. Subsequent pathological studies identified the lesion as a seborrheic keratosis reticulated lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 18

A suspected nose skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The recent lesion was observed to be dysplastic pigmented lesion.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be light. Variability of the lesion was determined to be even.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as not dark.

The lesion was believed to be harmless, and subsequent pathological studies identified the lesion as an intradermal lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 19

A suspected neck skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be an intradermal lesion.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be light. Texture of the lesion was determined to be even. The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

The skin lesion was further analyzed by again exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as not dark.

Results are illustrated in Table 1. Example 20

A suspected neck skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be a dysplastic papillary pigmented nevus.

Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be variable. The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

Results are illustrated in Table 1. Example 21

A suspected back skin lesion that caused itching was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. A clinical diagnosis of a malignant melanoma was made. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as dark variable.

Removal was proposed as case management, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses incorrectly indicated that tissue excision was desirable.

Results are illustrated in Table 1. Example 22

A suspected back skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The back lesion was observed to be a papillary nevus. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

Outline of the lesion was determined to be slightly irregular. Visible darkness of the lesion was determined to be dark in parts. Texture of the lesion was determined to be variable.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as dark. Outline was observed as irregular.

Tight follow-up was proposed as case management, and subsequent pathological studies identified the lesion as a compound lesion. The light analyses correctly indicated that tissue excision was unnecessary Results are illustrated in Table 1.

Example 23

A suspected wrist skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The lesion was observed to be a blue nevus.

The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be regular. Visible darkness of the lesion was determined to be light. Texture of the lesion was determined to be even. The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was not visible.

Minolta X-700 camera. Image tone was observed as light.

Finally, the skin lesion was analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm. The secondary light returned from the tissue was filtered through a Schott OG570 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Image tone was observed as dark. The lesion was believed to be harmless and subsequent pathological studies identified the lesion as a blue lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 24

A suspected cheek skin lesion was evaluated, in situ, by a skilled practitioner by marked visual observation under a bright light. A clinical diagnosis of a recent lentigo maligna was made. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera.

Outline of the lesion was determined to be slightly irregular. Visible darkness of the lesion was determined to be light. Texture of the lesion was determined to be dark in parts.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as medium variable.

Removal was proposed as case management, and subsequent pathological studies identified the lesion as resembling lentigo maligna but lacking essential features like back to back melanocytic hyperplasia. Results are illustrated in Table 1.

Example 25

A suspected neck skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. This recent lesion was observed to be a papillary nevus.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as medium. The lesion was believed to be harmless and subsequent pathological studies identified the lesion as an intradermal lesion. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Example 26

A suspected back skin lesion was evaluated, in situ, by a skilled practitioner by unaided visual observation under ambient light. The slightly changed lesion was observed to be a papillary pigmented nevus. The same skin lesion was analyzed by exposing, in situ, the tissue suspected of including the lesion to primary white light from an electric flash. The secondary light returned from the tissue was imaged on Fuji 400 RH color film with a Minolta X-700 camera. Outline of the lesion was determined to be very regular. Visible darkness of the lesion was determined to be medium. Texture of the lesion was determined to be even.

The skin lesion was also analyzed by again exposing, in situ, the suspect tissue to primary white light from the same source. Secondary light returned from the tissue was filtered through a Schott RG630 filter, and the selected secondary light was imaged on Fuji 400 RH color film with a Minolta X-700 camera. The lesion was visible.

The skin lesion was further analyzed by exposing, in situ, the suspect tissue to near ultraviolet light (SPECTRALINE Black Light - Black Light Eastern Corp. - average wavelength = 366 nm) . The secondary light returned from the tissue was imaged on Fuji 400 RH film with a Minolta X-700 camera. Image tone was observed as very regular. The lesion was believed to be a benign pigmented nevus, and subsequent pathological studies identified the lesion as a seborrheic keratosis. The light analyses correctly indicated that tissue excision was unnecessary.

Results are illustrated in Table 1. Summary

Thus in 17 cases, excision was found to be unnecessary. In only 5 cases, light-based analysis suggested removal whereas histo-pathological analysis dismissed the cases as non-malignant.

Primary white light. Secondary light filtered through Schott RG630 filter.

Primary light.

Primary white light.

Primary near uv light; unfiltered secondary light.

Primary white light. Secondary light filtered through Schott RG630 filter.

Primary light.

Primary white light.

Primary near uv light; unfiltered secondary light.

Primary near UV light; secondary light filtered through Schott OG570 filter.

Primary white light. Secondary light filtered through Schott RG630 filter.

Primary light.

Primary white light.

Primary near uv light; unfiltered secondary light.

Primary near UV light; secondary light filtered through Schott OG570 filter.

All patents and test methods above are hereby incorporated by reference.

Many variations of the present invention will suggest themselves to those skilled in the art in light of the above detailed description. Such obvious variations are within the full intended scope of the appended claims.

Claims

WHAT IS CLAIMED IS; 1. A method of analyzing tissue, said method comprising (a) exposing a tissue suspected of including a lesion, said lesion having (i) darkness, (ii) outline, (iii) texture, (iv) other morphological features, or (v) any combination thereof, to a primary light comprising at least one wavelength component of white light, to yield a secondary light from said tissue, said secondary light being comprised of at least one wavelength component; the wavelengths of said secondary light being the same as or different from those of said primary light, and (b) selecting at least one component of said secondary light, said component being selected from the group consisting of (i) those having a wavelength at least as long as the wavelength of red light and (ii) those having a wavelength at least as long as the wavelength of green light; and (c) displaying an image of said lesion derived from said selected secondary light components, whereby said lesion is capable of being distinguished from a normal tissue due to a difference in (i) darkness, (ii) outline, (iii) texture, (iv) other morphological features, or (v) any combination thereof, between said lesion and a normal tissue.

2. A method as defined in claim 1 which is non- invasive.

3. A method as defined in claim 1, wherein said lesion comprises a skin lesion.

4. A method as defined in claim 3, wherein said skin lesion comprises a malignant skin lesion.

5. A method as defined in claim 1, wherein said lesion comprises a cervical lesion.

6. A method as defined in claim 5, wherein said cervical lesion comprises a malignant cervical lesion.

7. A method as defined in claim 1, wherein said primary light comprises ambient light.

8. A method as defined in claim 1, wherein said selecting comprises filtering said secondary light to select each component of said secondary light having a wavelength at least as long as red light.

9. A method as defined in claim 1, wherein said selecting comprises filtering said secondary light to select each component of said secondary light having a wavelength at least as long as green light.

10. A method as defined in claim 1, wherein said displayed image comprises a photographic image.

11. A method as defined in claim 1, wherein said displaying comprises (1) digitizing said selected secondary light components; and (2) displaying an image of said lesion with said digitized components.

12. A method as defined in claim 1, wherein said displaying comprises (1) digitizing said selected secondary light components; and (2) displaying an image of said lesion with digitized components of said selected secondary light having a wavelength of red light.

13. A method of analyzing tissue, said method comprising (a) exposing a tissue suspected of including a lesion, said lesion having (i) darkness, (ii) outline, (iii) texture, (iv) other morphological features, or (v) any combination thereof, to a primary light comprising at least one wavelength component of ultraviolet light, to yield a secondary light from said tissue, said secondary light being comprised of at least one wavelength component, and the wavelengths of said secondary light being the same as or different from those of said primary light; (b) selecting at least one component of said secondary light having a wavelength at least as long as the wavelength of green light; and (c) displaying an image of said lesion derived from selected secondary light components, whereby said lesion is capable of being distinguished from a normal tissue due to a difference in (i) darkness, (ii) outline, (iii) texture, (iv) other morphological features, or (v) any combination thereof, between said lesion and a normal tissue.

14. A method as defined in claim 13, wherein said selected components comprise all of the components of said secondary light.

15. A method as defined in claim 13, wherein said selected components comprise all of the components having a wavelength at least as long as the wavelength of green light.

16. A method as defined in claim 13 which is non- invasive.

17. A method as defined in claim 13, wherein said lesion comprises a skin lesion.

18. A method as defined in claim 17, wherein said skin lesion comprises a malignant skin lesion.

19. A method as defined in claim 13, wherein said lesion comprises a cervical lesion.

20. A method as defined in claim 19, wherein said cervical lesion comprises a malignant cervical lesion.

21. A method as defined in claim 13, wherein said ultraviolet light comprises long wave ultraviolet light.

22. A method as defined in claim 13, wherein said selecting comprises filtering said secondary light to select each component of said secondary light having a wavelength at least as long as the wavelength of green light.

23. A method as defined in claim 13, wherein said displayed image comprises a photographic image.

24. A method as defined in claim 13, wherein said displaying comprises (1) digitizing said selected components; and (2) displaying an image of said lesion with said digitized components of said selected secondary light having a wavelength of green light. i

25. A method as defined in claim 13, wherein said displaying comprises (1) digitizing said selected secondary light components; and (2) displaying an image of said lesion with digitized components of said selected secondary light having a wavelength of green light.

26. A non-invasive method of aiding the detection of malignant skin lesions of a subject comprising the steps of (A) illuminating said subject with light, (B) selectively passing reflected light components of said subject of wavelengths only in the red portion of the visible spectrum, (C) digitizing said selectively passed light components, and (D) displaying an image of said digitized components, whereby malignant lesions may be distinguished from healthy tissue.

27. A non-invasive method of aiding the detection of surface tissue abnormalities of a subject comprising the steps of (A) illuminating the subject tissues by radiant energy in the visible light range, (B) deriving from the subject a digitized image of reflected spectral components of wavelengths only in the green range of the visible spectrum, and (C) displaying said digitized image.

28. A non-invasive apparatus for aiding the detection of malignancies of tissues of a subject illuminated by visible light, said apparatus comprising a filter for passing light reflected from said tissues in a band of wavelengths correlated to the type of tissue, an image sensing device for producing separate digital data representing a digitized image of said passed light, means for processing said digital data to produce digitized images of the red, green and blue components of said passed light, and a display device for displaying a visual image of one of said red, green or blue components, correlated to said tissue type, whereby presence of malignancy may be detected from characteristics of said visual image.