Laser reflectance imaging of human chest for localization of internal organs.

The normalized backscattered intensity (NBI) profiles at various locations of human thorax by multiprobe laser reflectometer are obtained. These data after digitization, interpolation, and filtering are color-coded and displayed as images on the outline of the human thorax. For optical characterization of tissues in terms of their parameters, scattering and absorption coefficients and the anisotropy parameter (g) are obtained by matching the measured NBI profile with that as obtained by Monte Carlo simulation procedure. Corresponding to the variation of the NBI over the various regions, the optical parameters show their respective changes. The maximum absorption and minimum scattering coefficients are observed at the areola, clavicle, sternum, scapula, and vertebral column. The minimum absorption and maximum scattering coefficients are observed at the pectoralis major of chest and rectus abdominis of abdomen regions, as compared to the other regions, attributed to their tissue compositional variations. To visualize the various tissues in lower regions of the thorax, the color-coded scheme of the NBI variation, as measured by the third fiber, is further expanded. By this procedure, the outlines of the heart and lungs, as detected through intercostals regions, are observed, which is in good agreement with that as determined by the chest radiograph of the same subject taken in PA position. Similarly the lower sections of the liver and stomach, due to their distinct optical parameters, are also observed.