PORT WINE STAINS TREATMENT SKIN
Laser treatment parameters are based on several factors, including lesion location, lesion morphology, and patient skin type.Light energy emitted by the flashlamp-pumped PDL is primarily absorbed by oxyhemoglobin contained within blood vessels, thus minimising thermal damage to other structures.
PDL is useful in the treatment of port wine stains ( vascular malformation), superficial haemangiomas and a variety of acquired cutaneous vascular lesions, including telangiectasis, cherry angiomas and poikiloderma of Civatte.The following skin disorders may be treated with pulsed dye laser (PDL) beams using an US Federal Drug Agency (FDA)-approved machine such as Vbeam Perfecta® (Candela Corporation, Massachusetts, USA) or flashlamp pulsed dye laser (Cynosure VLS, Massachusetts, USA). Complications result when energy intended for the target chromophore is non-selectively diffused and absorbed by surrounding tissues and structures.The skin chromophores commonly targeted by the pulsed dye laser is haemoglobin in blood.Absorbed energy is most responsible for the clinical effect because it is converted to thermal energy (heat) by the intended targets (chromophores), thereby killing the diseased cells.When pulsed dye laser light hits the skin, it is reflected, transmitted, or absorbed.This ensures that the impact of thermal energy is limited to the target structure and does not affect the surrounding tissue.The pulse duration of laser energy is shorter than the target structure’s thermal relaxation time, which is the time taken for the target to cool by 50% of its peak temperature after irradiation.The selected wavelength of laser light is absorbed to a high degree by the target structure (called chromophores) compared to surrounding tissue.The pulsed dye laser, when used for dermatological applications, works on the principle of selective thermolysis.Pulsed dye laser treatment can be combined with radiofrequency to enhance effects lower PDL doses possible with the combination can reduce adverse effects.Pulsed dye lasers produce pulses of visible light at a wavelength of 585 or 595 nm with pulse durations of the order of 0.45–40 ms.The incoming light excites the dye molecules into the state of being ready to emit stimulated radiation.The dye solution is usually circulated at high speeds, to help avoid triplet absorption and to decrease degradation of the dye.
A high energy source of light such as a fast discharge flashlamp or an external laser (eg, ruby laser or ND:YAG laser) is needed to "pump" the liquid beyond its lasing threshold.Some of the solvents used include water, glycol, ethanol, methanol, hexane, cyclohexane and cyclodextrin.Some of the laser dyes include rhodamine, fluorescein, coumarin, stilbene, umbelliferone, tetracene and malachite green.A dye laser is a laser which uses an organic dye mixed in a solvent as the lasing medium.Each of the different types of lasers has a specific range of utility, depending on its wavelength and penetration. Various kinds of lasers are available they are differentiated by the medium that produces the laser beam. LASERs (light amplification by stimulated emission of radiation) are sources of high-intensity monochromatic (single wave length) coherent light that can be used for the treatment of various dermatologic conditions depending on the wavelength, pulse characteristics, and fluence (energy output) of the laser being used and the nature of the condition being treated.
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