Comparison of a finite-element forward model with experimental phantom results: a

摘要

Abstract: We present a finite element (FE) model for calculation of photon propagation in highly scattering tissues. The model can either be used for time domain measurements, where the temporal distribution of transmitted light after an ultra short input pulse is measured, or for frequency domain measurements, where the input is a frequency modulated light source, and the phase shift and modulation depth between the input and output signal are measured. The FE model is used on inhomogeneous objects to investigate the effect of scattering and absorbing inhomogeneities on boundary measurements in both the time and frequency domain. The time and frequency versions are validated by comparing the results with data from analytical calculations and from a Monte-Carlo model. By comparing data from a two- dimensional and a three-dimensional FE model we derive a conversion factor for integrated intensity and mean time of flight that will permit the reconstruction of 3D data from a cylinder using a 2D FE model. The reconstruction is demonstrated on data generated with the FE forward model. !21