Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
  • A61B5/0075—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
  • A61B5/0077—Devices for viewing the surface of the body, e.g. camera, magnifying lens
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
  • A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
  • A61B5/441—Skin evaluation, e.g. for skin disorder diagnosis
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/47—Scattering, i.e. diffuse reflection
  • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
  • G01N21/474—Details of optical heads therefor, e.g. using optical fibres
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/47—Scattering, i.e. diffuse reflection
  • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/47—Scattering, i.e. diffuse reflection
  • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
  • G01N21/474—Details of optical heads therefor, e.g. using optical fibres
  • G01N2021/4742—Details of optical heads therefor, e.g. using optical fibres comprising optical fibres

Definitions

• the invention describes a method for the qualification of cosmetics and sunscreens for which a sun protection factor (SPF) or a protection factor still to be redefined is specified.
• SPF sun protection factor
• ISO 24444 defines a method for the in vivo determination of SPF.
• the basis of the method is the generation of erythema on the skin of subjects by radiation in the UVB range. Therefore, the process is harmful.
• the procedure In order to reduce the dependency of the result of interindividual variations of the skin characteristics, the procedure must be carried out on several subjects.
• ISO 24443 defines an in vitro method for determining the UVA protection factor (UVAPF).
• UVAPF UVA protection factor
• the sunscreen is applied to a plastic plate so that a transmission spectrum of the sunscreen can be measured. Due to uncontrollable variations of the procedure, the transmission spectrum is scaled to the result of the erythema test according to ISO 24444 and thus depends on its performance.
• the plastic plate used with a roughened surface is a relatively unrealistic skin model.
• ISO 24442 defines an in vivo method in which the UVA protection factor is determined by means of the minimum dose of UVA to produce an irreversible pigmentation (tan) the skin is determined. This procedure also causes a change in the skin of the subject.
• the sum of the light powers from the detection fibers is detected, so there is no defined distance between the illumination surface and the detection surface, but rather a summation of all distances.
• the backscattering is measured at several well-defined intervals.
• the error of such a measurement is strongly dependent on the used layer thickness (thickness of the separated layer of the pig's ear) and the surface roughness relative to the change by the (identical, normalized) amount of sunscreen and is in the measurements of the publication only against the ISO 24444 : 2010 evaluated in vivo evaluated SPF, not with each other. Also, only one type of sunscreen (oil-in-water) has been used, which has specific high scattering properties due to oil droplet formation, making the surface changes less effective.
• UVB radiation solar simulator, ie "solar simulator” with predetermined wavelength-specific intensity between 290 to 400 nm corresponding to solar radiation at sea level
• UVA radiation should be extended without restriction to the UVA, UVB, the visible and near-infrared or infrared range for the determination of corresponding sun protection factors with the solution according to the invention.
• the method according to the invention is not only desirable but urgently required for a number of important reasons:
• the UVA-PF method is based on "Minimal Erythematous Responses" and persistent pigmentation caused by UVA
• a detailed compilation of the PPD and erythema action spectra as well as the UVA and UV-SSR (ultraviolet solar simulated light) spectral irradiance in the 290- 373 nm offer the COLIPA Guidelines from 2009.
• DIN 67502 UVA balance
• the method is based on that described in the German Standard DIN 67502.
• the SPF is determined using the values provided in the CIE.
• the SPF is applied in order to correct the values obtained in vitro.
• the PPD are derived by applying the values from the PPD Action Spectrum given in the Standard.
• UVAPF UVAPF / SPF Ratio and Critical Wavelength
• Radical Protection Factor is the determination of the free radicals generated by solar radiation in human skin.
• this method again has the disadvantage that it can only be carried out in vivo using solar simulators, since in vitro samples which are not perfused have a significantly lower oxygen concentration.
• oxygen is the basis for the formation of free radicals.
• the radical protection factor and the sun protection factor differ.
• Tissue samples must be laboriously prepared for measurement in thin layers. Changes in the sample due to thermal or chemical preparation are to be expected and there is poor repeatability due to handling difficulties.
• crosstalk With the design options on the fiber applicator (crosstalk), the one (metallized fibers, recording plate with light barriers) and clear SRR measurement of handling (defined contact pressure), this can be disturbing. be minimized. Residual crosstalk can be detected and subtracted, if constant) with the measurement of a dark standard.
• the signals are large by varying the integration time of the measurement, an SPF can be too small and the very wide dynamic range can be detected because the required dynamics of the detector signals are linear with the integration time.
• the SPF is too heterogeneous locally. Due to the redundant measurement with several fibers for the same distance r, averaging can lead to a stable statement. In addition, some heterogeneity is physiologically realistic and is to be reproduced by the tissue model.
• the degree of heterogeneity can also be measured spatially resolved and provide valuable information about the distribution behavior of the sunscreen.
• Fig. 1 shows the measuring method according to the invention
• FIG. 2 shows the explanations for the derivation of the backscatter measurement according to the invention
• FIG. 3 shows model calculations on a skin model for the correlation of protection factor and backscatter. The registered line corresponds to equation (4).
• Fig. 4 shows the simultaneous measurement of the backscatter at several intervals
• FIG. 5 shows an embodiment of the backscatter measurement according to the invention, each having a lighting and detection fiber
• FIG. 6 shows embodiments according to the invention of fiber end surfaces of fiber bundles for the backscatter measurement
• the object is achieved by a method according to claim 1 and an apparatus according to claim 15.
• the measuring method according to the invention enables the damage-free determination of protective factors of formulations for light or radiation protection on tissue (skin) in vivo or in vitro or also on skin models (animal skin models or artificial materials). This is achieved by evaluating two measurements of the light backscatter on the skin surface before and after applying the radiation protection agent to the skin. In contrast to previous methods, the distance between the illumination surface and the detection surface on the skin is determined with the beam path of the measuring method (error! Reference source could not be found). The exposure dose of the skin used in the measurement is below the damage limit, which is usually indicated as MED for the UVB range or by means of MZB values for the other wavelength ranges.
• the illumination takes place with at least one radiation source which emits relevant radiation at least in the wavelength range for which the protective effect or the SPF is to be defined.
• the radiation source can emit only a smaller wavelength range of the radiation relevant for the protective effect and determine the existing radiation protection or sun protection factor by means of correlation measurements which precede the determination according to the invention.
• the emitted radiation is detected by at least one detector, wherein the detection area at the measuring location of the Einstrahlort the radiation source has a defined distance.
• the measuring cycle for determining the existing radiation protection or SPF consists of at least 2 individual measurements in which the radiation emitted by the radiation source of the illumination is transmitted through the measuring body (in addition to the layer modified by the applied radiation protection means) and hits the detector, the distance between the illumination surface and the detection surface on the measuring body being between the Measurements are predetermined, but different.
• a downstream device detects the at least two detector signals, amplifies these possibly with different degrees of gain, and analyzes the signal level with an algorithm that determines a sun protection factor.
• the advantages of this method lie in the lack of damage to the subject in in vivo measurements, in the simple recalculation without consideration of the incident light power must be constant only in the measurements with / without radiation protection, and also in the independence of the chosen distance between irradiation / Illumination and detection, and the existing under the radiation protection skin or optical properties of the measuring body or skin model used.
• Advantage of the measurement is the use of any spectral intensities in the radiation sources, which no longer require a calibrated "solar simulator".
• the detection can be carried out with simple detectors, which only have to output a signal above the noise depending on the definition of the sun protection factor for the transmitted radiation in the worst case of the greatest light attenuation by radiation protection means and measuring body.
• the method according to the invention gives the best results if the radiation protection agent to be investigated is present as a thin layer and weakens the transmitted radiation (see point 1 below).
• the attenuation by the radiation protection means can be approximately described by a scalar transmission factor T in this case.
• T transmission factor
• Pin denotes the illumination power, L (z) the path length-dependent light attenuation of the radiation through the skin.
• the sun protection factor (PF) is defined by the z-independent attenuation of the radiation density in the skin:
• the approach for the determination of the PF is to determine the transmission factor T with backscatter measurements, since the transmission through the skin with and without protective agent layer can not be detected directly.
• light is irradiated locally into a limited exposure surface of the skin surface. A portion of the light is remitted by scattering processes of the skin and measured in the area of a detection area (error! Reference source could not be found.).
• a distance r which, according to the invention, is chosen to be substantially greater than the layer thickness formed by the radiation protection agent. If the distance r is greater than the layer thickness formed by the radiation protection agent, the radiation transport from the illumination position to the detection surface can be described approximately by three sequential processes:
• the sun protection factor PF can be calculated from backscatter measurements before and after application of the radiation protection agent:
• the ratio R 0 hne / Rmit is independent of the distance r and z he qu.
• the backscatter is measured spectrally resolved.
• the resulting spectrum of the transmission factor ⁇ ( ⁇ ) can then be used to derive protection factors corresponding to the existing standards.
• ⁇ ( ⁇ ) is the intensity spectrum of the sun and ⁇ ( ⁇ ) the erythema spectrum, ie the spectra with an intensity sufficient for erythema to use.
• Other Light sources with an illumination spectrum ⁇ ( ⁇ ) or a wavelength range ⁇ ( ⁇ ) to be protected by the radiation protection agents result analogously in protective factors, which can likewise be determined according to the invention.
• backscatter and protection factor according to equation (4) can be confirmed with model calculations for UV light on a skin model. Error! Reference source could not be found, showing corresponding results of Monte Carlo calculations for the radiative transfer equation. Radiation protection agents with varying scattering and absorption properties were assumed, furthermore the melanin content of the epidermis was varied. It turns out that the backscatter measurement described here is approximately independent of the special properties of the radiation protection agent, this is not the case for the methods of backscatter measurement described in the prior art.
• a maximum value for r is due to the amount of radiation still striking the detector, that is to say the effect of the light attenuation by the radiation protection means AND of the underlying skin.
• a practical value of 1 mm will be an upper limit for UV irradiation / protection formulation.
• Particularly preferred is a value of r ⁇ 200 ⁇ .
• the attenuation T is independent of r, so that the measurements can be detected with too small a distance and excluded from the evaluation in order to avoid a wrong determination of the PF.
• Equation (4) can be calculated using this measurement a correction term g can be extended, which reduces errors in the prediction of the PF.
• the formula for determining a corrected sun protection factor is:
• the skin has furrows and crevices, which lead to a laterally inhomogeneous application of the radiation protection agent and thus to a location-dependent fluctuation of the sun protection factor and also influence the backscatter by different formation of the skin in this area. These influences are only recorded when taking measurements on the skin.
• the methods mentioned in the prior art and based on PMMA substrates do not detect this, or restrict them in the case of embossed structures.
• a localized remission measurement is carried out with which this heterogeneity of the transmission can be determined by multiple measurements at adjacent positions. This can be determined on the one hand from a suitable averaging a mean attenuation and thus a mean PF.
• the variance of the damping can be determined, so that properties of the radiation protection agent with respect to the application to the skin can be examined.
• the abrasion behavior and in the distribution of the radiation protection agent over the service life can thus be provided by the measuring method described a method for further qualification.
• the method described here has a wider range of applications compared to the existing methods which use erythema, pigment or radical formation.
• the existing procedures can be measured repeatedly on a sample; once induced erythema or pigmentation can not be repeatedly generated.
• the sun protection factor can be detected spectroscopically in all required wavelength ranges.
• the measurements are sequentially at the same location on the measuring body, z. As the skin performed. This is done by measuring continuously for short periods of time and for longer ones Time intervals with measurement pauses, in which the optical interface of the measuring device is removed from the measuring location and periodically replaced at the same location. Since the measurement does not change the skin (redness) or measuring body, the advantage of the method is that it can be performed several times at the same measuring location without distorting the measured values. If multiple measurements are made, on the one hand the progress of the protective effect can be observed, which is not carried out with previous MED-based methods for ethical reasons due to the large number of sample sites / sites with invasive measurement.
• the MED-based procedure can not be used because the determination is based on the appearance of redness, but it does not (as in sunburn) decrease in relevant protection periods (hours). Furthermore, the skin is pre-damaged at the site and does not provide reliable information on the duration until a complete regeneration (days) until damage occurs.
• the measurement is carried out at measuring sites loaded with different amounts and / or types of radiation protection agent, or after interaction with the applied radiation protection agent at the same measuring location. This is done by the optical interface of the measuring device removed, an application of further radiation protection agent or an interaction takes place at the measuring location (wiping / rubbing with a defined procedure, rinsing with water or the like, bleaching with light, etc.) and then another measurement takes place, which is based on the original measurement without radiation protection. It is also conceivable to refer the measurement to the measurement carried out before the interaction.
• the advantage of the method is the detection of mechanical effects on the radiation protection and the possibility at the same measuring location (for example spine as usual or forehead) to quantify these influences more easily.
• the measurement takes place at different measuring locations with the same distance from the illumination surface to the detection surface.
• a sun protection factor which is usually collected on the back with more practice-relevant sites for radiation protection, such as the face or forehead or the bald head in the case of sun protection or in other radiation protection situations, for example, exposed to radiation hands.
• This is done by the optical interface of the measuring device is positioned at these locations. There must be no change in the measurement procedure or on the device. So far, a measurement with the "solar simulator" for ethical and cosmetic reasons (there remains a rectangular redness) not at naturally exposed sites.
• the inventive method is due to the low illumination dose without damage or redness and can also be placed on almost any location on the skin of a subject or other skin models, also due to the geometry of the optical interface.
• a plurality of detectors are arranged such that they have the same distance to one of the radiation sources.
• the measurement is carried out several times without removing the optical interface of the measuring device, and analyzes the temporally successive measurements.
• the successively determined sun protection factors are also analyzed and the measurement is ended when the successive sun protection factors differ less than a standard deviation of 1 ⁇ from one another, ie assume a stable value.
• Other stability criteria are also in accordance with the invention. Deviations of the determined sun protection factors can result from the bleaching behavior, the penetration behavior into the measuring body or the skin or technical influences in the measuring device.
• the method allows, without limitation, the multiple measurement and the analysis is not time-consuming, since the measured values are calculated by a pre-established algorithm from the detector-derived, wavelength-resolved signals.
• a plurality of measurement projects are carried out.
• the measurement projects are carried out at different positions on the measuring body.
• the measured values obtained at the different positions are averaged.
• the measurement projects are also repeated.
• the measurement bodies acted upon by the radiation protection agent are measured a first time between the individual measurement projects. After this first measurement the measuring body may be exposed to the protective effect of the radiation protection agent. Subsequent to this, the measurement project is then repeated. This happens at best with the same parameters and at the same position we the first measuring project.
• the influences acting externally on the protective effect of the radiation protection agent can be time, water, abrasion, the action of the radiation or other influences. Measurements before and after exposure to the effects can be used to determine the effects on the protective effect. This makes it possible to optimize the protective agent in terms of resistance to the influences and thus to ensure the best possible protection.
• a measurement can be carried out on the measuring body before the radiation protection agent has been applied to the measuring body.
• the radiation is detected spectrally separated for wavelengths or wavelength ranges and then analyzed for the separate wavelengths or wavelength ranges.
• the spectrally separated wavelengths or wavelength ranges may include UV-A, UV-B and / or the visible light.
• the spectral separation can be done directly behind the radiation source and before the penetration of radiation into the measuring body.
• the radiation backscattered by the measuring body can be spectrally separated into a plurality of wavelengths or wavelength ranges.
• characteristic values of different types are determined from the measured values. These characteristics are based on different damage functions. These damage functions can be the effect of UV-A radiation or completely different wavelength ranges on the skin or in continuation on other biological materials (eg wood for wood preservatives) by acute reactions or other damage (eg DNA strand breaks in living biological material ).
• this procedure has the advantage that the locally acting radiation dose can be reduced if the spectral separation takes place before penetration of the radiation into the measuring body.
• this approach has the advantage that the calculation of the sun protection factor can be independent of the respective spectrum and also independent of the detector characteristic.
• the radiation is irradiated to a limited area. This area is separated from the detector area.
• the sun protection factor of the radiation protection agent according to the formula
• the measuring head is cleaned before the measurement project.
• the cleaning is preferably carried out by means which leave no residue and / or have no influence on the characteristic of the radiation. This has the advantage that all measurement projects can be carried out under the same optimal conditions. In this way, the radiation dose can be lowered further, since no contamination for the intensity of the radiation falling on the measuring body has to be taken into account.
• the individual measurements are carried out for a plurality of distances between the detector and the radiation source.
• the distances are in this case in a range of 0 mm to 1 mm, preferably from 20 ⁇ to 0.5 mm and more preferably from 60 ⁇ to 200 ⁇ be varied.
• the method can be used for a very large wavelength range, not limited by lamp spectra, erythem spectrum, reactions of the measuring body, or the like.
• the method according to the invention also offers the possibility of the spectral range (SPF is defined only for UVB) for the measurement expand, since only with UVB skin reactions (MED) are to be found.
• SPDF spectral range
• MED UVB skin reactions
• the influence of substances on the measurement according to the invention is avoided, which influences skin rash or UV-induced erythema.
• the inventive method is simpler and more meaningful than the previously known methods and associated with lower costs.
• a device for non-invasive determination of the sun protection factor of a radiation protection agent comprising a sensor unit, wherein the sensor unit comprises at least one radiation source and two detectors, wherein the detectors have different distances to the radiation source, or either at least two radiation sources and a detector, wherein the radiation sources have different distances to the detector, or a radiation source and a detector, wherein the distance between the radiation source and the detector is variable.
• the radiation source is suitable for emitting light in the region in which the protective effect is to be defined, the distances between the individual radiation sources and the detectors being determined. This range includes in particular the visually visible light (VIS) as well as the UV-B and the UV-AB range.
• the radiation source can emit light.
• the device according to the invention has a controller for controlling the radiation source, wherein the controller is adapted to control the radiation source such that the radiation source emits a maximum light dose of small MED and / or MZB, via an analysis unit which is suitable, the detected radiation taking into account respective distances between the radiation source and the detector to analyze and an output unit that outputs the determined value.
• the radiation sources and detectors are arranged in sudstreuan angel.
• the device according to the invention has the possibility of changing test parameters such as wavelength, distance r between radiation source and detector and / or spot sizes. This offers the possibility to adapt the measuring parameters and in particular the light dose to the measuring conditions in such a way that the measurements on the Measuring body radiated light dose can be minimized without affecting the quality of the analysis.
• the distance of a radiation source and a detector is selected so that the detected radiation has passed completely through the layer of the measuring body in which the applied radiation protection agent is located.
• the distance between one or more radiation sources and one or more detectors between 0 and 1 mm, wherein the distance is selected so that the penetration depth of the radiation greater than the layer thickness and / or penetration depth of the radiation protection agent in the Skin is. This ensures that the relevant for the determination of the sun protection factor areas of the measuring body are completely irradiated.
• the device has one or more radiation sources and at least one illumination surface, wherein the illumination surface of the radiation sources between a circle with 07 ⁇ and 1 mm 2 , preferably between a circle with 0100 ⁇ and 250 ⁇ 2 and more preferably between a circle with 0 200 ⁇ and a circle with 0 400 ⁇ lies.
• An optional embodiment of the invention has one or more detectors and at least one detection surface, wherein the detection surface between a circle with 07 ⁇ and 1 mm 2 , preferably between a circle with 0100 ⁇ and 250 ⁇ 2 and more preferably between a circle with 0 200 ⁇ and a circle with 0 400 ⁇ lies.
• the advantage is achieved that the illumination surface of the radiation sources on the one hand is large enough to bring in enough light, but not too large, that from a certain size only edge region is effective and increases the etendue. This also limits the light dose required for the analysis.
• the radiation source emits light in accordance with the solar spectrum.
• the analysis unit resolves the measurement spectrally with subsequent weighting according to the typical solar spectrum. This corresponds to the product of light intensity of the radiation source and detector sensitivity to the product of solar spectrum and Wirk upon. Damage spectrum.
• This has the advantage that no special radiation sources or detectors for the device must be used because the weighting is done later in the analyzer and can be adapted to the given from the existing procedures for determining a sun protection factor product of solar spectrum and effect or damage spectrum or also other rules for the determination of a sun protection factor.
• the device for measuring the measured quantities has fiber arrangements or optically imaging systems with reducing optics. This ensures that the spatial resolution can be significantly improved, or inexpensive components can be used, which can produce the same illumination or detection surface through the reduction optics.
• the distance-dependent backscattering it is possible to select fiber arrangements or also optical systems which image light sources and detectors on the skin surface.
• the light from one or more light sources is radiated into the skin over a limited illumination surface, light backscattered from one or more detection surfaces of the skin is detected by detectors or by a spectrometer.
• the backscatter must be measured before and after the application of the radiation protection agent at the same position on the skin. To find the measuring position with the least possible error, a positioning aid is favorable.
• the spectrally resolved backscatter first results in a spectrum ⁇ ( ⁇ ) of the transmission factor (equation (4)), from which, for example, for sunscreen formulations with equation (5), a standard-compliant protection factor is calculated.
• the spectrum of the light source and the spectral sensitivity of the detectors can be chosen so that the measured detector signal is proportional to the integral in equation (5).
• a simple arrangement consists, for example, of an illumination fiber and a detection fiber, which are placed on the skin surface at a suitable distance from each other (error! Reference source could not be found) and thus determine the illumination and detection area.
• Detection fibers with the same distance to the illumination fiber are combined on the output side and coupled to a detector. Instead of the detectors, an imaging spectrometer can be used to simultaneously measure the backscatter spectrum for each distance. In an extended embodiment, the backscatter signal is measured in each detection fiber. The variance of the signals allows conclusions to be drawn about the inhomogeneity of the protective properties of the investigated radiation protection agent erroneous measurements or incorrect application of the radiation protection agent can be detected.
• the transmission factor can be averaged over a larger spatial area, or its variance can be determined.
• Outlier or erroneous measurements can be detected by comparing the measurements at different distances r and at different positions of the skin and excluded from the evaluation.
• b) configuration can also be several units of error! Reference source not found.
• a) sketched configuration are combined into a fiber bundle. B here denotes the illumination fiber, 1 to 4, the different fibers at certain intervals (1 near, 4 maximum removed). a. Repetitive measurements at different measuring points either by automatic shifting of the measuring arrangement or by manual displacement further increase the statistical accuracy.
• cans can be used, which are below a possible damage.
• a stable measurement can take place with a defined spot size in the contact and a defined numerical aperture or defined light propagation.
• a pressure measurement or also a support aid with an enlarged surface the pressure dependence of the measurement can be reduced and the vertical support controlled, the latter prevents the optical crosstalk of illumination and detection.
• absorbent or reflective materials between the fibers optical crosstalk can be reduced, thus further improving channel separation.
• low-fluorescence materials incorrect measurements are prevented.
• Interchangeable films which are attached by means of a fiber applicator or window can prevent the spread of radiation protection agents and ensure sterile use ((also used in the method described in the literature by Ruvolo et al., See page 3) )).
• a suitable cleaning must be carried out between the measurements at different measuring locations or test persons.
• the contamination of the sensor can be detected by the measuring arrangement itself, for example, by taking a measurement in the free space or in a dark measuring chamber inside.
• the spectral dependence of the remission can be determined by using a spectrometer or by illuminating the skin with multiple light-emitting diodes.
• the measurement for different spectral ranges can be done simultaneously or sequentially to either adjust the amount of light for a good signal-to-noise ratio on the detector side or to allow the spectral resolution.
• the measuring head is positioned perpendicular to the sample surface before the measurement.
• the disturbance light is filtered out by modulation techniques, eg lock-in techniques.
• a correction of the measured data is carried out taking into account the backscatter at the illumination position.
• the detected radiation is analyzed separately for individual radiation source / detector pairs.
• Wavelength ranges light from the spectra UV-A and / or UV-B and / or VIS VIS and / or IR includes.
• the device according to the invention is furthermore distinguished by the following features which can be combined with one another independently of one another:
• the distance 0 measurement between the radiation source and the detector is used for calibration.
• the calibration is only necessary with respect to the spectral position, an intensity does not have to be calibrated, since the relative measurements with / without radiation protection mean that the measurements of the irradiated intensity are independent of the measurements, provided that they do not change appreciably between the measurements.
• Devices which shield the detectors from radiation that has not been transmitted through the protective cream and / or skin or measuring body.
• the analysis unit of the device is suitable for detecting outliers and erroneous measurements.
• a point on the inside of the lower arm is first subjected to a formulation similar to the radiation protection agent but without a light-damping effect. This serves to compare the measurements with / without radiation protection agent and increases the accuracy, but is not mandatory for carrying out the method or determining a sun protection factor. Thereafter, this location is measured with the measuring device by light at a defined area of about 200 ⁇ diameter - generated, for example by placing an optical fiber (illumination fiber) with a core diameter of
• 1 MED equals the lowest irradiation dose which, when read after 24 hours, caused a sharply limited erythema (redness) of the skin. This dose varies greatly even among people with the same skin type. In fair-skinned people of skin type II 1 MED equals about 250-400 J / m 2 (25-40 mJ / cm 2 ). Damage can also be prevented by falling below the MZB values.
• MZB are in the DIN EN 60825-1 "Safety of laser equipment - Part 1: Classification of equipment, requirements and user guidelines", the international standard IEC 60825-
• BGV B 2 The accident prevention regulation "Laser Radiation” (BGV B 2) also contains these values, additions and changes, in particular on the basis of DIN EN 60825-1: 2001-1 1, are listed in BG Information 832 "Operation of Lasers".
• the underlying limit values come from the ICNIRP (International Commission on Non-Ionizing Radiation Protection).
• This light passes through the skin of the sample and passes at a predefined distance - for example, 60 ⁇ - from a detection surface, which in turn may consist of a patch optical fiber (detection fiber), which has a core diameter of 200 ⁇ .
• a detection fiber detection fiber
• a plurality of detection fibers can be arranged equidistant from the edge of the illumination fiber in an optical measuring head, which is in direct contact with the measuring location, and be guided together to a detection device and thus the intensity can be measured .
• the signal generated by the radiation is amplified by a defined factor, which also provides a signal above the noise for the subsequent measurement of the weaker intensity.
• the detection is carried out with wavelength resolution.
• the resolution may be, for example, 1 nm and should be selected depending on the definition of the sun protection factor.
• the standards provide for a procedure that can be followed or deviated from without affecting the performance of the measurement process. Only the meaning of the determined sun protection factor for the application scenarios of the radiation protection agent is dependent on the type of exposure.
• a further measurement of the same type is carried out at the same measuring location. This completes the measuring cycle after two individual measurements.
• This similar second measurement is charged with the first measurement, for example, according to the above equation (4). This calculation is carried out with wavelength resolution for the area in which the SPF is to be defined.
• An SPF for example, is the SPF, which is valid for sunscreen in the UV-B range.
• the individual measurements are averaged or added up (accumulated).
• the measurement cycle thus includes, for example, 10 to 50 individual measurements without radiation protection agent (or without light attenuation in the radiation protection agent) and an equal number of measurements after application of the radiation protection agent.
• the measurements after application of the radiation protection agent can be detected only after a waiting time after the application of, for example, 2 minutes.
• Other types of analysis are also conceivable wherein the wavelength resolved signal values of the individual measurements are all taken into account without being contracted to a wavelength resolved value prior to analysis (equation (4)).
• a modification of one of the preceding embodiments is also a measurement cycle only with a limited wavelength range, for example with illumination by coupling a 365nm LED into the illumination fiber.
• preliminary work is required, which takes place with the radiation protection agent and a broader wavelength range and forms a basis for correlating the values in the restricted wavelength range with an SPF. It must be ensured as a prerequisite for a correlation that the measurement at 365 nm does not show different spectral light attenuation compared to the comparative measurements for the type of radiation protection agent used in the case of preliminary work and measurement.
• the preceding determination of the sun protection factors is assigned to a measured light attenuation at 365 nm.
• the light protection factors are then determined by comparison with previously known values in the analysis apparatus via this assignment (correlation).
• a third measurement after an interaction of the same type is also to be carried out at the same measuring location.
• the measuring device is used similarly.
• the interaction may be, for example, ten times light pressure wiping and a wet terry towel, or other light, mechanical, or moisture or combination effects.
• This third measurement is evaluated against the first measurement according to equation (4) and gives a 'sun protection factor after interaction' which is compared to the 'sun protection factor without interaction' (determined from the first and second measurements) and from this the effect of the interaction on the protective effect can be determined. It makes sense to use such a method with interaction in tests for water resistance of the radiation protection agent and in statements on the change of the sun protection factor by mechanical effects by dressing and changing, which should be part of a product information.
• the interaction may also be to detect the change of the radiation protection agent over time by measurement after a short period of time - for example during the first minutes after exposure - or over a longer period of time - for example 2 hours after exposure.
• the procedure is the same.
• chemical changes of the radiation protection agents can be detected or the pull-in behavior and its effect on the sun protection factor.
• the individual measurement takes a few seconds, the analysis either takes place immediately (several hundred milliseconds) or the measuring signals of the detectors are buffered.
• third measurements are carried out periodically, for example every 5 seconds, and analyzed until the deviation of the successive values lies below the simple standard deviation, ie shows stable values. Such an evaluation takes place in the analysis device, which ends the measurement when the stable values are reached and signals this to the user.
• a further measurement is also to be carried out at another measuring location in the same way.
• the SPF of the same radiation protection can be compared with similar job at different locations.
• a first measurement (individual measurement without radiation protection agent) at the additional measuring location is used as the basis for the analysis of the further measurement.
• UVAPF UVA protection factor according to the in vitro method according to ISO 24443
• MED minimal erythema-producing dose corresponds to the minimum dose until it reaches a reddening of the skin
• MZB maximum allowable irradiation e.g. determined by regulations or by a radiation protection commission
• UVA wavelength range of light from 380 nm to 315 nm
• UVB wavelength range of light from 315 nm to 280 nm
• VIS wavelength range of light from 380 nm to 780 nm
• NIR wavelength range of light from 780 nm to 1400 nm
• IR wavelength range of light from 780 nm to 1 mm
• T scalar transmission factor (wavelength dependent) characterizes the

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