Experimental study of the effect of absorbing and transmitting inclusions in highly scattering media

Experimental results are presented for the cw reflected signal from a dense random medium containing inclusions of absorbing material or glass. It is shown that a glass inclusion is more difficult to detect than an absorbing one. A glass rod has two effects on the reflected signal: a waveguiding effect that reduces the signal and a transmission effect that increases it. The overall effect of the glass rod depends strongly on the distribution of light inside the sample around the inclusion and hence on the scattering liquid itself. This implies that for experiments modeling tissue interactions the parameters of scatterers used should be as close as possible to the tissue parameters.