ANALYSIS OF LAYERED SCATTERING MATERIALS BY PULSED PHOTOTHERMAL RADIOMETRY - APPLICATION TO PHOTON PROPAGATION IN TISSUE

A model of pulsed photothermal radiometry (PPTR) based on optical diff usion theory is presented for a turbid, two-layer, semi-infinite mediu m containing a surface layer whose optical absorption and scattering p roperties differ from that of the underlying layer. Assuming one-dimen sional geometry, we develop expressions for the depth-dependent fluenc e distributions and radiant-energy-density profiles and for the time d ependence of the PPTR signal. Experimental tests of the PPTR model in a series of layered phantoms of varying optical properties are describ ed. The results of these tests are consistent with the model predictio ns.