Path length resolved optical Doppler flowmetry

The readings in laser Doppler perfusion monitoring are affected by the optical properties of the tissue in which the microvasculature is embedded, through their effect on the optical path lengths. Thus for a constant perfusion, the LDF output signal is affected by the variance in individual photon path lengths due to the changes in tissue optical properties and probe geometry. We will present efforts to render blood flow measurements independent of the tissue optical properties by using low coherence interferometry. We will give evidence of the improvement in quantification of our approach. In particular we show that low coherence interferometry can measure dynamic properties of particles in Brownian motion, independent of optical properties of the surrounding tissue matrices. Furthermore, demonstration is given of the applicability of the method in vivo