WO2012048890A1

WO2012048890A1 - Probe head device and method for enhanced diagnostics

Info

Publication number: WO2012048890A1
Application number: PCT/EP2011/005169
Authority: WO
Inventors: Sune Svanberg; Mikkel Brydegaard
Original assignee: Spectracure AB
Current assignee: Spectracure AB
Priority date: 2010-10-14
Filing date: 2011-10-14
Publication date: 2012-04-19
Anticipated expiration: 2013-04-14

Abstract

A probe head for topical illumination of a tissue sample and collection of backscattered light therefrom. The probe head comprising, a body having a distal end and a proximal end, the distal end arranged for apposition to a surface of the sample for covering a surface area thereof, a light source mounted elevated and inclined in said body for seguentially illuminating a central portion of the surface area, a detector at the proximal end perpendicularly positioned to detect backscattered light from the central portion.

Description

TITLE: Probe head device and method for enhanced

diagnostics

BACKGROUND OF THE INVENTION

Field of the Invention

This invention pertains in general to the field of non-invasive diagnosis of suspected dermatology lesions, such as skin neoplasms, neurodegeneration, diabetes, chronic kidney disease or premature aging of skin. More particularly the invention relates obtaining and analysing multispectral images or spectral databases from

illumination of a skin tissue. Even more particularly the invention relates to a hand-held probe head to covering a surface area to be investigated using multi-spectral imaging .

Description of the Prior Art

It is known that optical spectroscopy is an effective method for characterisation of composition of material. It also known that spectroscopy is can be used for diagnosis of various conditions, for example of medical nature.

If spectral data can be collected from a number of points, sequentially or at the same time, multi-spectral imaging may be performed. By using multispectral imaging analysis relevant information may be extracted and shown, for example as a false-colour image. Two phenomena may be used for multi-spectral imaging either reflectance where the objects colours are measured or fluoresces.

In the articles:S. Andersson-Engels et al, "Clinical recording of laser induced fluorescence spectra evaluation of tumour demarcation feasibility in selected clinical specialities2, Laser Med. Sci. 6, 415 (1991); U. Gustafsson et al, "Compact Fiber-optic Fluorosensor using a

Continuous-wave Violet Diode Laser", Rev. Sci. Instr. 71, 3004 (2000); C. af Klinteberg et al, "Compact Medical Fluorosensor for Minimally Invasive Tissue Characterization", Review of Scientific Instruments 76, 034303 (2005) and S. Ek et al, "Compact Fibre-Optic

Fluorosensor Employing Light-Emitting Ultraviolet Diodes as Excitation Sources", Spectrochimica Acta B63, 349 (2008), discloses different systems and devices for diagnosis of lesions, i.e. skin cancer, employing optical fibres wherein the illumination and the collected light are transmitted in the same optical fibre or in a bundle of optical fibres.

In K. Svanberg et al, "Clinical Multi-colour Fluorescence Imaging of Malignant Tumours - Initial

Experience", Acta Radiol, 38, 2 (1998) a cancer detector employing multi-spectral imaging is disclosed based on laser induced fluoresces.

An important application is to diagnose human skin tissue to discover lesions e.g. rodent ulcer or squamous cell carcinoma. Changes may be discovered using auto- fluorescence or by employing more specific spectroscopic signals from supplied photosensitizers .

Newly studies of auto-fluorescence have been

conducted collecting spectral signals from substances such as Advanced glycinated end products (AGE) . These studies have indicated that AGE-signals are related to a number of illnesses, such as neurodegeneration and/or diabetes and/or chronic kidney disease.

The diagnostics of malignant tumours is a clinical challenge - frequently a tissue sample (biopsy) has to be taken for microscopic evaluation by an experienced

pathologist. This is a both expensive and slow process with the outcome often delivered with a week, delay or more. In dermatology lesions and structures suspected to be

dangerous by the patient are removed in clinics without prior pathology - most frequently later pathologically found to be benign and resulting in a very large cost to the health care system. This state of matters to a large extent is due to the risk of missing a life-threatening malignant melanoma, which is hard to diagnose even with a very trained dermatologist^'s eye.

Thus, there is a need for a new device and method to enhance diagnostics. Preferably performed by a small, handheld device non-invasively would be an advantage over the systems and methods used today.

Recently, light emitting diodes (LEDs) have become readily available at low cost. Unfortunately, such light sources are known to have an emission profile being temperature dependent (i.e. unstable) which may cause issues with artefacts which is an issue when used for diagnosis .

Hence, an improved device wherein the advantage of the low costs and smallness of LEDs could be exploited would be advantageous .

In particular a hand held device allowing for increased flexibility, cost-effectiveness, rapid and/or reliably diagnosis would be advantageous.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing a device and a method that may be used to investigate or diagnosing suspected lesions, according to the appended patent claims.

The invention is designed for non-invasive

investigation and diagnosis of suspected lesions located at an easily accessible locations, such as a location on human skin. The invention measures the surface optical

characteristic for an unaffected state or a present state by using a hand held probe head. The hand held probe head is configured to detect backscattered spectra from sequentially illumination of a surface or detect the backscattered light using multispectral imaging. This could be conducted either separately or in combination.

According to aspects of the invention, a probe head is provided for topical illumination of a tissue sample and collection of backscattered light therefrom. The probe head comprising, a body having a distal end and a proximal end, the distal end arranged for apposition to a surface of the sample for covering a surface area thereof, a light source mounted elevated and inclined in the body for sequentially illuminating a central portion of the surface area, and a detector at said proximal end perpendicularly positioned to detect backscattered light from the central portion.

According to another aspect of the invention, a method is provided for topical illumination of a tissue sample and collection of backscattered light therefrom. The method comprising, providing a body comprising a light source and a detector, positioning the body apposition to the sample for covering a surface area thereof,

illuminating sequentially a central portion of the surface area in an angle using the light source, and detecting backscattered light using the detector perpendicularly positioned related to the surface area.

According to yet a further aspect of the invention, provides for use of the invented device or the method, for detection of a dermatology lesion, such as neoplasms and/or neurodegeneration and/or diabetes and/or chronic kidney disease and/or premature aging of skin.

Further embodiments of the invention are defined in the dependent claims, wherein features for the second and subsequent aspects of the invention are as for the first aspect mutatis mutandis.

Some embodiments of the invention provide for a hand held device for cheap and fast non-invasive

investigation/diagnosing of suspected dermatology lesions, thereby avoiding the need of biopsy.

Some embodiments of the invention also provide for a hand device wherein optical fibers are not employed for transmitting light to and from a tissues site. Instead the light sources and preferably the detector are integrated into the hand-held device. This will lead to less intensity losses than if fibers were being used.

Some embodiments of the invention also provide for a hand held device wherein the illumination and detection of light is performed without being in contact with the sample. This is especially an advantage when investigating or diagnosing skin tissue, since artifacts and/or

interferences of a signal may be caused by fibers pressing away the blood, resulting in large changes in the spectral signal . Some embodiments of the invention also provide for a hand-held device utilizing temperature stabilization of a LED emission profile from the current-voltage

characteristics of the LED. Thereby making LED a viable option for a hand-held spectroscopic device.

Some embodiments of the invention also provide for a hand-held device able to investigate or diagnosing for example a suspected dermatology lesion in a present state. It should be emphasized that the term

"comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

Fig. la and b illustrate that a LED diode's

temperature may be established from its current-voltage characteristic- Fig. 2 is showing a vertical cross-section of an exemplary embodiment of a probe head;

Fig.3 is showing a horizontal cross-section of an exemplary embodiment of a probe head; and

Fig. 4 is showing a 3D illustration of an exemplary body of a probe head. DESCRIPTION OF THE PREFERRED EMBODIMENTS

Specific embodiments of the invention now will be described with reference to the accompanying drawings.

This invention may, however, be embodied in many different forms and should not be construed as limited to the

embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements .

The following description focuses on an embodiment of the present invention applicable to a hand held probe head for non-invasive diagnosis of suspected dermatology lesions and in particular to a multi spectral imaging device.

However, it will be appreciated that the invention is not limited to this application but may be applied to many other type of organic tissues including for example

detection of forgery in forensic sciences, visualize early signs of agricultural diseases, such as of leaves.

In an embodiment of the invention according to Fig. 2-4, a probe head having illuminating and detecting

function for increased efficiency for handling of light is illustrated. The probe head may be used to non-invasive measure a skin surface' s real optical characteristic in its present state. The probe head may be used to investigate or diagnosing easily accessible locations, such as human skin. For the invented probe head there are no fibres being in contact with the tissue surface (i.e. skin) for

illumination or detection of light. Thereby may no signal artefacts arise in the detected signal as otherwise being common. Artefacts of the signal may be due to the fibres pressing away the blood from the site, resulting in large changes in the spectral signal . Interferences or

distortions in the spectral signal may also originate from skin humidity which may change the coupling of a spectral signal, especially utilizing fibres in contact with a skin surface .

In Fig. 2 a vertical cross-section of an exemplary embodiment of a probe head 1 is illustrated. The probe head is made of a body 19 being cupped to create an open-end cavity 8. When holding the body 19 of probe head 1 against a surface of a sample 17, the cavity 8 becomes an enclosed space. The surface area 7 being covered by the cavity 8 is the surface area 7 to be investigated or diagnosed.

The body 10 is having bores 9 to hold light sources 13, 20. Light source 13 is here illustrating a LED or laser diode and light source 20 is illustrating a broad banded light source for reflectance measurements. The light source 13 may be a narrow banded light-source having an emission of from 245 nm and up to about 7 micrometres and an emission width preferable of 10 to 20 nm. For example, the narrow emission may be at 355, 375 or 395 nm.

A probe head 1 may in some embodiments only comprise of one or a plurality of narrow light sources 13.

Additionally and/or alternatively, in some embodiments, the probe head 1, may comprise of only one or a plurality of broad banded light sources 20. Additionally and/or

alternatively, in some embodiments, the probe head 1 may comprise any combinations thereof.

The detector 11 is here illustrated as a fibre connectable to an external spectrometer or detector.

Optionally, the detector may be connected to the body 19 using a contact 12, such as a SMA contact. Additionally and/or alternatively, in some embodiments, the detector 11 may be an integrated to the body 19. The integrated detector may for example be a CCD or CMOS for multispectral imaging. Additionally and/or alternatively, in some embodiments, the detector 11 may be an integrated LED or diode detector.

In some embodiments of the invention a layer 18 being a thermal and/or electric isolating material may be arranged between the body 19 and the surface of sample 17. Layer 18 may be a changeable contact matrix.

The light sources 13, 20 are arranged elevated and inclined or angled in relation to the surface area 7. Thereby may at least a portion 16 of the surface area 7 be illuminated by the light sources 13, 20. Portion 16 may be a central part of the surface 7. The detector 11 may be arranged perpendicular to collect backscattered light from the illuminated portion 16. This arrangement is an

advantage, since specular reflected light may not be detected by the detector, because the angle of the

illuminating light may cause the specular light to not hit the detection surface of the detector.

Alternatively and/or additionally, in some embodiment the narrow banded light sources 13 may be used as an excitation source to obtain fluorescence. When used as an excitation source for fluorescence a short-pass filter 14 may be fitted in front of the light source 13. The short pass filter may eliminate emission components in the light source 13 which may fall within the wavelength range of the detected backscattered fluorescence light.

Alternatively and/or additionally, in some

embodiment, a long-pass filter may be fitted in front of the detector to block excitation light, such as Ultraviolet light, but permit fluorescence light to pass.

Additionally and/or alternatively, polarisation filter may be used in front of lights sources and/or detector .

In Fig. 3 a horizontal cross-section of an exemplary embodiment of a probe head 1 is illustrated. As illustrated a probe head 1 may have more than one narrow-band light 13a-c sources and/or more than one broadband light source 20a-c. If more than one narrow band light source 13a-c is used, each may have a different narrow emission.

Additionally and or alternatively, if more than one broad band light source 20a-c is used, each may cover different broad emission of wavelengths. Each narrow band light source 13a-c may be fitted with an optical filter 14a-c.

Lights sources 13a-c, 20a-c may be arranged elevated and inclined or angled in a "ceiling" of a cavity. The Light sources 13a-c, 20a-c should preferably be configured to direct emission of light towards the same portion 16 of the sample area 7 (for reference see Fig 2) . A detector 11 is centrally and perpendicularly arranged to detect the backscattered light from the illuminated portion of the surface being covered by body 19.

Alternatively and/or additionally, in some

embodiments of the invention, the body 11 may be fitted with a heat sink 23 for temperature stabilisation of the probe head 1. Alternatively and/or additionally to a heat sink 23, a Peltier cooling element may also be mounted for increasing the temperature stabilisation of the probe head 1.

In Fig. 3, a 3D illustration of an exemplary body 49 of a probe head 1 is shown. A detector may be fitted in a central bore 41. The central bore 41 may in some

embodiments also be configured with an element 51 for positioning a long-pass optical filter in front of the detector. The body 49 may also have bores for receiving light sources 43, 50. The light source receiving bores 43, 50 may be arranged around central bore 41. The light source receiving bores 43, 50 may be configured to direct the emitted light to the same spot being a portion of a surface area covered by the body 49.

Alternatively and/or additionally, the bores 43 for receiving narrow banded light sources may be configured with an element 44 for positioning a short-pass optical filter in front of the light source. Alternatively and/or additionally, in some

embodiments the body 49 may be configured to hold a heat sink at position 53.

LEDs are a cheap but there emission spectra may be affected by the temperature of the diode. This may give difficulties to evaluate data. One way of overcome this is to mount the LEDs on a temperature stabilising heat sink. Another alternative is to monitor the real light emission which may be used for a compensation of the spectral shift.

The inventor has shown (illustrated in fig. la and lb) that a diode's temperature and thereby the real

emission profile may be established from a diode's current- voltage characteristic. The plots 5 and 6 in fig la and b illustrates how the current-voltage characteristics change for a LED having different temperatures T. Thus this current voltage characteristic may be used for

stabilisation for a diode such as a LED. The current- voltage characteristic may easily be determined from the drive circuit of the diode. Thus, making LEDs a viable option as a preferred light-source in a hand held device, such at the present invention.

For the application of the invention it has been established that LED with an emission width of 10-20nm may replace relatively expensive narrow laser diodes .

Especially for human tissue, where rarely structures exist being sharper than on the lOnm scale. The low cost of LEDs make it possible to employ a number of LEDS as light sources for sequentially excitation of fluorescence using a plurality of various wavelengths. By using more than one LED each with a different emission wavelength, more

diagnostic information will be obtained (registration of Excitation-Emission Matrices). Another possibility with LEDS is to employ broad-banded white-light LEDS for investigation of reflection characteristics (colour- characteristics) by using spectroscopy.

In the present invention at least a portion of the surface covered by the probe head is illuminated with light in an oblique angle. Thereby may specular reflexions

(direct reflexions from the surface) be directed away from the detector and not interfere or disturb the collection of light which have interacted with the sample. Specular reflexions are tangible when surfaces are humid.

A plurality of light sources may be used sequentially where backscattered light may be collected for each of the light sources. The collection of light may be conducted in a spectral mode using a detector. Alternatively, more than one detector may be used to collect the backscattered light. The detector may be at least one fibre connected to the entrance slit of an external spectrometer.

Alternatively and/or additionally, the detection may be conducted in a multi-spectral mode using a CCD or CMOS detector, such as a camera. By using multi-spectral mode, the detector may register backscattered light from

different parts of the illuminated portion of a sample.

The collected backscattered light may be reflected light. Alternatively and/or additionally, the collected backscattered light may be fluorescence light.

In some embodiments, laser diodes or LEDs may be modulated very fast using their drive current. Phase-shifts and demodulation of the detected light may then be employed to investigate the life-time of studied molecules' excited states. Further, diffusion processes within a sample may be investigated which may enhance diagnostic and

differentiation . The body of the probe head is configured to

positioning the compact light sources for illuminating a portion of a surface to be investigated. The shape and/or configuration of the body ensure that background light or ambient light is debarred from the enclosed cavity which is obtained when the body is positioned to cover an area of a surface to be investigated.

The light sources may illuminate the portion of the surface area to be investigated from the "ceiling" and/or the walls of the cavity.

In some embodiments the body of the probe may be made of a material having optical characteristics to allow an investigator (i.e. a medical practitioner) to see through the body of the probe head while the body still debar interfering background light or ambient light.

The contact surface between the body of the probe head and the surface may in some embodiments be a layer of a thermal and/or electrical isolating material to isolate the body of the probe head from the surface. This may increase the temperature stability of the emission profile of the light sources. The layer may be a contact matrix which may be exchanged between each investigation.

Alternatively and/or additionally, the layer may be of a material easy to clean or made aseptic. If necessary the material of the isolating layer may be of a material which could be sterilised.

In a similar way as discussed in an article by M. Brydegaard, et al, "Broad-band Multi-Spectral Microcopy Imaging Transmission Spectroscopy Employing an Array of Light-Emitting Diods (LEDs, American J. Phys . 77, 104 (2009) the inventors propose to use a plurality of LEDs . The LEDs may have emission wavelengths ranging from 330 nm to 1.2 micrometers to illuminate a surface where for example a suspected tumor is located.

The surface may be sequentially imaged from reflected light by activating LEDs, one after the other. For each LED recording an image using a suitable imaging system with a suitable detector. A normal digital camera operating in black-and white mode, optionally with the IR filter removed, may be used. The LEDs may irradiate the surface to be studied inside a small enclosure or cavity, typically an openen-ended can-shaped enclosure or cupped body, where the opening is pressed against the tissue to block out ambient light. A rubber or disposable cushion material may provide the light-tight coupling to the tissue.

The detector (i.e. a camera) may be placed with its optical aperture in the opposite end of the enclosure or cavity. The LEDs should be appropriately shielded to avoid stray light from the LEDs entering the detector directly. Preferably only light reflection from the surface should be collected by the detector.

Compared to a normal color assessment with the naked eye, this type of image recording would extend the spectral range of the eye (400-700 nm) substantially both towards short wavelengths, and in particular to near-IR

wavelengths. The latter is particularly interesting for improved diagnostics of malignant melanoma, which appear very black and unstructured in the visible region due to heavy contents of melanin. However, in the near-IR region this absorption is strongly reduced and new features of diagnostic value for discrimination of malignant melanoma against other tumor types of less lethal lesions may be performed .

A plurality of images may be treated using

multivariate analysis methods, such as principal component analysis, to create a contrast function which after the application of a suitable threshold may yield a false- colour image. The false-colour image may display the presence of a selected feature (such as malignant melanoma) only. UV-LEDs may also be used in combination with

appropriate long-pass filters, arranged in front of the detector, to record fluorescence images using different excitation wavelengths. Such fluorescence images may be included in the analysis to isolate the sought after features .

By obtaining a number of spectra using sequential illumination a spectral dataset is created.

Preferably, the multispectral imaging device as described herein may be incorporated in a hand-held unit, which the dermatologist may hold against a suspicious skin area .

Additionally and/or alternatively, a device according to the present invention may in some

configurations also be used for other tasks, such as industrial inspection, detection of forgery in forensic sciences, to visualize early signs of agricultural diseases in leaves, components for circuit cards etc.

The invented device may be coupled to a compact separate computer for image analyses. Alternatively the device may have an integrated dedicated processor in the hand-held unit, providing real-time display of the features being under investigation. While LED:s are very suitable devices for the illumination of the sample, other light sources such as filtered incandescent lamps, diode lasers, semiconductor laser etc may be anticipated for the illumination .

The present invention has been described above with reference to specific embodiments. However, other

embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above, performing the method by hardware or software, may be provided within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.

Claims

A probe head for topical illumination of a tissue sample and collection of backscattered light therefrom, said probe head comprising: a body having a distal end and a proximal end, said distal end arranged for apposition to a surface of said sample for covering a surface area thereof; a light source mounted elevated and inclined in said body for sequentially illuminating a central portion of said surface area; a detector at said proximal end perpendicularly positioned to detect backscattered light from said central portion.

The probe head according to claim 1, wherein said body is cupped-shaped .

The probe head according to claim 1 or 2, wherein said body has an open-ended cavity arranged to be directed with said open-end towards said sample.

The probe head according to any preceding claims, wherein said body comprises a bore to hold said light source.

The probe head according to any preceding claims, wherein said body is at least partly made of a thermal and/or electric isolating material. The probe head according to any preceding claims wherein said body comprises a contact matrix to be arranged between said body and said sample.

The probe head according to claim 6, wherein sai contact matrix is exchangeable.

The probe head according to any preceding claims wherein said detector comprises a fibre arranged at said proximal end perpendicularly positioned and connectable to an external detector .

The probe head according to any preceding claims wherein said detector is an imaging system.

The probe head according to any preceding claims wherein said detector comprises a fibre arranged at said proximal end perpendicularly positioned and connectable to an external spectrometer having a detector.

The probe head according to any preceding claims wherein said detector comprises CCD or CMOS arranged at said proximal end perpendicularly positioned .

The probe head according to any preceding claims wherein said detector comprises a digital camera arranged at said proximal end perpendicularly positioned .

The probe head according to claim 12, wherein said digital camera is configured for a black an white mode.

The probe head according to any preceding claims wherein said probe head comprises a changeable optical filter element fitted before said

detector and/or said light source.

15. The probe head according to any preceding claims, wherein said detector is configured to detect a spectral sequence of sequentially illumination of said central portion of said surface area.

16. The probe head according to claim 15, wherein

said spectral sequence is a spectral dataset.

17. The probe head according to any preceding claims, wherein said detector is configured to detect a multispectral image of said central portion of said surface area.

18. The probe head according to any preceding claims, wherein said backscattered light is reflected light from said surface area.

19. The probe head according to any preceding claims, wherein said backscattered light is fluorescence light from said surface area.

20. The probe head according to any preceding claims, wherein said backscattered light is fluorescence light and reflected light from said surface area.

21. The probe head according to any of claims 1-7, wherein said detector is a LED based detector or diode based detector arranged at said proximal end perpendicularly positioned.

22. The probe head according to any preceding claims, wherein said light sources are modulated for time resolved detection of a phase-shift.

23. The probe head according to any preceding claims wherein said light source and/or said detect are arranged in relation to each other such that specular reflection are not detectable.

24. The probe head according to any preceding claims comprising an analysing unit configured for multivariate analysis methods.

25. The probe head according to claim 24, wherein said analysing unit is configured to create a contrast function from said backscattered light detected .

26. The probe head according to claim 24 or 25,

wherein said analysing unit is an external unit connectable to said probe head; and/or an integrated unit.

27. The probe head according to any preceding claims wherein said light source is a white light source .

The probe head according to any preceding claims wherein said light source is a LED, laser diode, semiconductor laser.

29. The probe head according to any preceding claims wherein said light source comprises a fibre connectable to an external light source.

The probe head according to any preceding claims wherein said body comprises at least two light sources configured to sequentially illuminate said surface area. The probe head according to any preceding claims, wherein said probe head is a handheld device.

The probe head according to any of claims 24 to 26, wherein said analysing unit is configured for providing a display of a feature under

investigation .

The probe head according to claim 32, wherein said display is provided in real-time.

The probe head according to any preceding claims, wherein a temperature emission profile of said light source is established from a current- voltage characteristic of said light source.

A method for topical illumination of a tissue sample and collection of backscattered light therefrom, said method comprising: providing a body comprising a light source and a detector; positioning said body apposition to said sample for covering a surface area thereof; illuminating seguentially a central portion of said surface area in an angle using said light source; detecting backscattered light using said detector perpendicularly positioned related to said surface area.

36. The method according to claim 35, comprising

obtaining a spectral dataset by detecting backscattered light of said sequentially

illumination .

. The method according to claim 35, comprising detecting a multi-spectral imaging.

. The method according to any preceding claims, comprising analysing said detected backscattered light using multivariate analysis methods.

. The method according to any preceding claims, comprising creating a contrast function by

detecting backscattered light of said sequentiall illumination .

40. The method according to any preceding claims, comprising temperature stabilisation of said light source by establishing an emission profile of said light-source from an obtained current-voltage characteristic of said light source.

41. Use of the device according to any of claims 1 to 34 or the method according to any of claims 35 to 40, for detection of a dermatology lesion, such as neoplasms and/or neurodegeneration and/or diabetes and/or chronic kidney disease and/or premature aging of skin.