On the potential of human sinus cavity diagnostics using diode laser gas spectroscopy

A method for studying human sinus cavities and inflammation status is described. Diode laser spectroscopy of molecular oxygen gas in the cavity is performed at 760 nm through the strongly scattering facial tissue in a backscattering geometry. Model experiments on tissue-like scattering plastics were made to elucidate the possible penetration depths and the expected signal levels. Measurements on the frontal sinuses of a healthy volunteer verify the viability of the technique. The potential for dynamic gas measurements of the possible occlusion of the channels connecting the sinuses with the nasopharyngeal cavity are discussed, and demonstrated in model experiments using a gas with a composition different from that of the ambient air. Extensions to other biomedical diagnostics arenas are discussed. The results obtained suggest that a complementary method for real-time and non-intrusive medical diagnostics using compact instrumentation could be developed.