Optical Coherence Tomography OCT

Non-invasive technology that was originally used in ophthalmology, but has also gained importance in dermatological diagnostics since 1997. Physically, OCT is based on the principle of interferometry: coherent light waves are projected onto a tissue, in this case the skin - the delay or intensity of the reflections is measured based on the interference behavior at the various layers. In contrast to laser scanning microscopy, OCT uses an infrared laser beam (wavelength 1300 nm) to scan the skin. A three-dimensional image of the skin can be generated in real time by delaying and intensifying the reflection of the coherent light waves at interfaces of different structures with correspondingly different refractive indices. This reconstruction is called tomography. The infrared signal penetrates up to 1.5 mm into the skin, i.e. much deeper than with laser scanning microscopy.

In dermatology, OCT is mainly used for the early diagnosis of small, non-specific skin tumors (e.g. in the differential diagnosis of basal cell carcinoma), both pigmented and non-pigmented skin tumors. It is also useful for therapy planning - either spreading the tumor before surgery or monitoring conservative therapy measures.

Dermatological: mainly skin tumors, nail pigmentation, also mycoses, vascular processes.