ABSTRACT
Laser-Doppler flowmetry (LDF) is a method able to provide continuous noninvasive measurements related to changes in microvascular perfusion, in terms of relative changes of blood volume and velocity. The method is based on the effect of the light on moving (mainly erythrocytes) and nonmoving components of a limited volume of tissue. Unlike ultrasound Doppler, for which one might establish the velocity of the blood and its flow within a single vessel if a relatively limited number of factors related to the structure to be investigated are known (incidence angle, vessel diameter, velocity profile), in LDF methodology the extraction of red blood cell velocity and volume cannot be obtained directly. The backscattered light is detected and transformed into an electric signal by solid-state miniature devices, photodiodes, or phototransistors.
