DETERMINATION OF THE OPTICAL-PROPERTIES OF THE HUMAN UTERUS USING FREQUENCY-DOMAIN PHOTON MIGRATION AND STEADY-STATE TECHNIQUES

The optical properties (absorption and transport scattering coefficients) of freshly excised, bulk human uterine tissues were measured at 630 nm using frequency-domain and steady-state photon migration techniques. Measurements were made on both normal (pre- and post-menopausal) and non-neoplastic fibrotic tissues. The absorption coefficient of normal postmenopausal tissue (approximately 0.06 mm-1) was found to be significantly greater than that of normal pre-menopausal tissue (0.02-0.03 mm-1) and pre-menopausal fibrotic tissue (0.008 mm-1). The transport scattering coefficient was similar in all three tissue types considered (0.6-0.9 mm-1). From the preliminary results presented here, we conclude that optical properties can be reliably calculated either from the frequency-dependent behaviour of diffusely propagating photon density waves or by combining the frequency-independent photon density wave phase velocity with steady-state light penetration depth measurements. Instrument bandwidth and tissue absorption relaxation time ultimately determine the useful frequency range necessary for frequency-domain photon migration (FDPM) measurements. Based on the optical properties measured in this study, we estimate that non-invasive FDPM measurements of normal uterine tissue require modulation frequencies in excess of 350 MHz.