Copper-bromide laser system for treatment of dermatological malformations

摘要

The work presents a cosmetic CuBr laser system for treatment of various cutaneous vascular malformations and pigmented lesions with output power 3 W at 578.2 nm and 6 W at 511 nm. The system is provided with a fiberoptic delivery system and a hand-piece, which forms a convergent beam with a diameter of the laser spot 0.4 mm in the focal plane. A built-in CPU sets and controls all operational modes by using an intracavity polychromatic acousto-optic modulator or a mechanical shutter. The laser irradiation can be emitted within a preset temporal interval with variable duration from 15 to 950 ms. The controllable interval for thermal relaxation of the irradiated tissue can be varied from 20 to 1000 ms. The controllable radiant exposures vary from 5 to 100 J/cm~2 for the yellow light and from 10 to 100 J/cm~2 for the green light. A 3D Monte-Carlo modeling has been used to compare the volumetric energy deposition at 532, 578.2 and 585 nm. The model simulates photon migration for the case of embedded cylindrical small blood vessels of varying size, which are randomly distributed within a skin layer at different depths. To simplify the task, the vessels were modeled as parallel to each other and to the tissue surface. Optical properties (absorption coefficient, scattering coefficient, anisotropy factor, and index of refraction) of epidermal tissue, dermis and blood were chosen from the literature.