Non-Invasive Imaging and Characterization of Human Thorax Tissues by Non-Contact Scanning Multi-Probe Laser Reflectometry and Monte Carlo Simulation

The normalized back-scattered intensity (NBI) profiles at various locations on the human thorax of a subject were obtained by multi-probe laser reflectometer. The laser radiations are guided by an optical fiber onto the human thorax tissues and the backscattered radiations are collected by three optical fibers placed at distance of 2 mm, 4 mm and 6 mm from the input fiber. The data collection of the human thorax tissue is carried out using an automatic non-contact scanning system controlled by the personal computer. The data after digitization, interpolation and filtering, are color-coded and displayed on the outline of the human thorax. These NBI pattern vary depending on the muscular, anatomical and vascular compositions and also on percentage of fat composition at various locations. For optical characterization the optical parameters, scattering (mu_s) and absorption (mu_a) coefficients and the anisotropy parameter (g) at each location on the human thorax, by matching of reflectance profiles with that as simulated by a Monte Carlo simulation (MCS) procedure were determined. The point-to-point variations of the optical parameters and NBI variations at various regions of the human thorax tissues are studied