Laser treatment of leg veins: Physical mechanisms and theoretical considerations

BACKGROUND AND OBJECTIVES: A discussion of laser treatment of leg veins is based on a review of the literature, theoretical analysis, and the clinical experiences of the authors. Theoretical computations are discussed within the context of clinical observations. STUDY DESIGN/MATERIALS AND METHODS: A Monte Carlo model is used to examine volumetric heat production, fluence rate, and temperature profiles in blood vessels at 1,064 and 532 nm wavelengths with various beam diameters, vessel diameters, and pulse durations. RESULTS: Clinical observations, Monte Carlo results, and a review of the literature suggest that longer wavelengths and longer pulses durations favor vessel contraction over intraluminal thrombosis. Monte Carlo simulations show that longer wavelengths are more likely to uniformly heat the vessel compared to highly absorbing wavelengths. Methemoglobin production causes deeply penetrating wavelengths to generate more volumetric heat for the same input radiant exposure. CONCLUSIONS: Clinical observations and models support the role of long wavelengths and long pulses in optimal clearance of most leg telangiectasias.