Abstract

A multiwavelength, high bandwidth frequency-domain photon migration instrument has been developed for quantitative, non-invasive measurements of tissue optical and physiological properties. The instrument produces 300 kHz to 1 GHz photon density waves in optically turbid media using a network analyzer, an avalanche photodiode detector and four amplitude-modulated diode lasers. The frequency-dependence of PDW phase and amplitude is measured and compared to analytically derived model functions in order to calculate absorption, μ, and reduced scattering, μ, parameters. The wavelength-dependence of absorption is used to determine tissue haemoglobin concentration, oxygen saturation and water concentration. We present preliminary results of non-invasive FDPM measurements obtained from normal and turnout-containing human breast tissue. Our data clearly demonstrate that physiological changes caused by the presence of small palpable lesions can be detected using a handheld FDPM probe.