Penetration of the laser light into the skin in vitro.

BACKGROUND AND OBJECTIVE

Knowledge of the optical parameters of the skin is important for all kinds of phototherapy. We analyzed penetration of laser light and proved different optical properties of in vitro specimens of normal skin and granular tissue from skin ulcers.

STUDY DESIGN/MATERIALS AND METHODS: An He-Ne laser (lambda = 632.8 nm, output 50 mW) and a semiconductor laser (lambda = 675 nm, output 21 mW) were used. The distribution of laser radiation was detected by a CCD camera and evaluated by the image analysis software DIPS.

RESULTS

Transmittance in granular tissue was about 2.5 times higher than that in normal skin. In the thickest skin sample (2 cm), approximately 0.3% of He-Ne laser and 2.1% of semiconductor laser light penetrated.

CONCLUSIONS

The results demonstrate the percentage of incident light penetrating the individual skin layers in different localizations on the skin surface, which is a decisive factor for the selection of the radiation dose.