Tissue characterization with ballistic photons

摘要

We propose tissue characterization with ballistic photons, those whose direction or propagation speed is not affected by the presence of tissue. The most critical aspect of the tissue characterization problem is calibration of experimental measurements. The calibration method relates the fringe irradiance (power modulation in one interferometer arm) with the sample concentration under controlled conditions. During this step, the absorption and scattering indices β_a and β_(SC) are determined as a function of concentration for each material or tissue of interest, using a set of containers to vary travel distance D. It is assumed that linear scattering coefficient, k_(SC) (absorption coefficient, α_a), is proportional to the number of scattering particles per unit volume, or particle concentration, c, in [ml/1]. Attenuation is proportional to concentration of scattering (absorption) centers and the sample length. The sensitivity of method is estimated at 10"'9 with uncoated plate beam-splitters and intensified photon-counting detector.