Pickering J W
Laser Centre, Academic Medical Centre, Amsterdam, Netherlands.
J Photochem Photobiol B. 1992 Oct 30;16(2):101-11. doi: 10.1016/1011-1344(92)80002-d.
Heat-induced changes in the scattering and absorbing properties of tissue begin with the denaturation of protein. Using egg albumen and egg yolk as tissue phantoms, the changes in absorption and scattering coefficients and the average cosine of the scattering angle have been quantified from 350 to 850 nm for heating corresponding to an empirical damage parameter from 3.7 to 1430 (albumen) and from 0.067 to 28 (yolk). In addition to being useful for modelling the response of tissue to laser light, the changes in optical properties yield information on the particle size distribution in the phantoms. For a low damage parameter the albumen has a large percentage of small, so-called Rayleigh scattering, particles owing to the initial denaturation of the protein. As the damage parameter increases, the percentage of these particles decreases. In the yolk, the effect of denaturation of proteins on the scattering characteristics is still present but less pronounced, because of the initial highly scattering nature of the tissue and perhaps to other rate processes that also occur.
