Transmission measurements on tissue-like phantoms: a simple system for optical parameter determination

In last years NIR radiation was extensively used to detect targets hidden in optically turbid media. We performed transillumination measurements on tissue-like phantoms (absorbing objects embedded in Intralipid and black ink solutions) to determine the intensity of transmitted radiation. The experimental apparatus include a diode laser ((lambda) emiss equals 820 nm, CW power equals 250 mW), a detection fiber (diameter equals 600 mm), a PMT and a Digital Signal Analyzer (bandwidth equals 1 GHz). At variance of very complex systems that reject highly scattered photons by time-resolved detection, the developed system performs this selection by collimation. The experimental data were compared with diffusion approximation predictions.