A New Scheme for Time-Resolved Diffusing Wave Spectroscopy

摘要

Diffusing Wave Spectroscopy (DWS) consists in the measurement of temporal correlation of the electromagnetic field in the diffusion regime, allowing a scan of dynamical properties deep inside a medium. DWS is of special interest in biomedical optics, as it is sensitive to blood circulation in capillaries inside the tissue.rnHowever one main difficulty of this technique concerns data extraction which implies to perform an inverse problem taking into account the geometry and the optical coefficients of the medium. The use of time-resolved detection has been proved to be an efficient tool to discriminate the DWS information, but the photon path lengths were up to now limited to a few tens mean free paths.rnIn order to perform time-resolved DWS for much longer photon paths, we used a new method, based on the use of an interferometer and a wavelength modulated source. We have already demonstrated that this method, in addition to its lower cost, was very efficient to perform time-resolved measurements of the light scattered by a thick scattering medium. We will show in this poster some measurements performed by transillumination through a thick medium (4cm), opening the possibility of Time-Resolved DWS measurements in the human breast.