title: Polarized light imaging specifies the anisotropy of light scattering in the superficial layer of a tissue.
abstract: This report describes how optical images acquired using linearly polarized light can specify the anisotropy of scattering (g) and the ratio of reduced scattering [μs′=μs(1−g)] to absorption (μa), i.e., N′=μs′/μa. A camera acquired copolarized (HH) and crosspolarized (HV) reflectance images of a tissue (skin), which yielded images based on the intensity (I=HH+HV) and difference (Q=HH−HV) of reflectance images. Monte Carlo simulations generated an analysis grid (or lookup table), which mapped Q and I into a grid of g versus N′, i.e., g(Q,I) and N′(Q,I). The anisotropy g is interesting because it is sensitive to the submicrometer structure of biological tissues. Hence, polarized light imaging can monitor shifts in the submicrometer (50 to 1000 nm) structure of tissues. The Q values for forearm skin on two subjects (one Caucasian, one pigmented) were in the range of 0.046±0.007 (24), which is the mean±SD for 24 measurements on 8 skin sites×3 visible wavelengths, 470, 524, and 625 nm, which indicated g values of 0.67±0.07 (24).
authors.affiliation: Oregon Health & Science University, Biomedical Engineering, 3303 SW Bond Avenue, Portland, Oregon 97239, United States.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Jacques
authors.affiliation: Université Paris Saclay, Polytech Paris-Sud, 300 Rue du Château, 91400 Orsay, France; LPICM, CNRS, Ecole Polytechnique, 91128 Palaiseau, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Roussel
authors.affiliation: Oregon Health & Science University, Biomedical Engineering, 3303 SW Bond Avenue, Portland, Oregon 97239, United States.
authors.forename: Ravikant
authors.initials: R
authors.lastname: Samatham
mesh_terms: D016880:Anisotropy; D003199:Computer Systems; D006801:Humans; D008027:Light; D009010:Monte Carlo Method; D012542:Scattering, Radiation; D012867:Skin / Q000000981:diagnostic imaging*