EVALUATION OF SPATIAL-RESOLUTION AS A FUNCTION OF THICKNESS FOR TIME-RESOLVED OPTICAL IMAGING OF HIGHLY SCATTERING MEDIA

Previous experimental and theoretical investigations of the utility of time-resolved methods as a means of optical imaging through the human breast have indicated that a spatial resolution of approximately 1 cm is achievable by isolating the shot-test path length photons which pr opagate through the tissue. Studies have also shown that resolution ma y be improved further by extrapolating the measured distribution using an appropriate model of photon transport. The experiments described h ere were performed in order to observe the relationship between achiev able spatial resolution and the thickness of the medium. For a given t ime gate, an improvement in the spatial resolution was observed as the object thickness was reduced. Overall, the results indicate that a br east compression of about 1 cm may improve the limiting spatial resolu tion by as much as 7 mm. Less encouraging is the implication that temp oral extrapolation over several orders of magnitude in intensity is re quired to achieve a comparable improvement in spatial resolution. (C) 1997 American Association of Physicists in Medicine.