Problem of macroinhomogeneity detectability in optical tomography studies of strongly scattering media

Murzin, V. B. Volkonsky, 0. V. KravtsenvukResearch Institute for Laser Physics, Science Center' S.I.Vavilov State Optics Institute", 199034 St.Petersburg, RussiaPh: +7 812 2185594, fax: +7 812 2185891, E-mail: somsi1ph.spb.suABSTRACTIn the diffusion equation approximation, the photon mean trajectory (PMT) and photon path deviation werecalculated in relation to scattering medium optical characteristics and methods of measurements (time- or frequency-domain).It was shown that in macroinhomogeneity detection there exists an optimum combination between the spatialresolution (which is defined by photon path standart deviations from PMT) and the value of signal perturbationinduced by inhomogeneities.One can evaluate this optimum by the scale matching of photon path rms deviations and macroinhomogeneitysize. In turn, such a matching can be realized by the proper choice of the source and detector mutual positions and thevalues of temporal delay in time-domain or modulation frequency in frequency-domain measurements.Key words: diffusion approximation, statistical characteristics ofphoton paths. arbitrary shadow1. 1TTRODUCTION .