Mechanism of action & application

UV-Phothotherapy

Properties of optical radiation
The spectrum of optical radiation is between 100nm (UV) and 1 million nm (IR)

Optical properties of the skin
The illustration below shows the effect of optical radiation on the skin. In this context, the skin is seen as a non-homogeneous medium consisting of four layers:

stratum corneum & stratum spinosum = epidermis (50-150µm thick incl. stratum basale)
Dermis (0.8-1mm)
Subcutis (1-3mm)

The named layers have a different chromophore distribution, so that the reflection, transmission and scattering properties are different depending on the wavelength. The figure illustrates the respective penetration depth of the wavelength.