Application of fiber optic spectroscopy in disease diagnosis based on skin reflectance and fluorescence

Equipment and methods:

AvaSpec-2048-2 dual-channel spectrometer from AVANTES was used, with two input fibers covering the 250-1100nm band and a resolution of 2nm. A laptop was used to display, store and process data. Four light sources were used - AVANTES's AVALIGHT-HAL as a high-stability, broadband spectral output light source for reflectance spectroscopy and colorimetry research; the other three light sources were used to excite fluorescence - blue and green lasers and AVANTES's blue LED light source (AVALIGHT-LED-400). All light sources used SMA fiber connectors to facilitate connection with optical fibers.

Figure 1

The three probes for fiber optic detection of the skin shown in Figure 1 have been mature and tested in practice. Solution A is a Y-shaped fiber bundle, which consists of a detection fiber (connected to the spectrometer) surrounded by 6 illumination fibers, all of which have a core diameter of 200 μm and are made of quartz. This probe can be used to measure diffuse reflectance directly in contact with the skin, or it can be fixed on a cylindrical fixture tilted at a certain angle (Figure 1, view A) to measure skin color and surface reflectance at a certain distance. The fiber separation distance of this probe cannot exceed 1 mm, so the detection in contact mode can only obtain the reflectance ratio of the surface layer of the skin. To obtain deeper light, a dual-fiber probe with a variable internal fiber distance (2-6 mm) can be used (view B). In order to improve the quality of skin fluorescence spectra, a dual-tilted probe (view C) was also designed, which contains a groove with filters for laser and LED wavelengths.

Conclusion

To verify the performance of this system, some data of healthy skin areas and diseased skin areas of the same patient were collected, as shown in Figures 2 to 4. Figure 5 shows the fluorescence obtained by exciting healthy skin with blue and green lasers.

In summary

, portable and versatile fiber optic spectroscopy detection technology has a good application prospect in the rapid and non-invasive diagnosis of skin diseases.

Common configurations of skin spectroscopy: