Comparison of entropy and polarization memory rate behaviors through a study of weakly-anisotropic depolarizing biotissues

Polarization measurements 70 days after irradiation of a living pig allowed us to distinguish between a healthy skin sample and a 15 Gy- or 20 Gy-irradiated one. In this way, polarization characteristics based on Mueller's matrix formalism for depolarizing media such as biological tissues can be analyzed via the entropy factor. But, in the case of a weakly-anisotropic depolarization like the one observed with cobalt-irradiated samples of skin, such an analysis is no longer applicable. We show, here, that another parameter called the polarization memory rate can highlight a quantitative evolution in the depolarization anisotropy of the irradiated samples under study. This potentially provides an interesting insight into the differences between the scattering properties of tissues and tissues phantoms.