Conclusion

A generic optical fiber probe with a source fiber and a collection fiber can be modeled by a transport function T(u_a, u_s') where u_a is the absorption coefficient and u_s' is the reduced scattering coefficient.

The absorption u_a is modeled as the superposition of contributions from blood, water, bilirubin, and background protoporphyrin IX.

The scattering is modeled as u_s' = a nm^-b.

The behavior of T(u_a, u_s') is well characterized by Mexp(-u_aL), where M and L are functions of u_s'.

For skin sites, the role of epidermal melanin is modeled such that measurement = exp(-f_melu_a.melL_epiT(u_a, u_s'), where f_mel is the volume fraction of melanosomes in the epidermis, u_a.mel is the absorption coefficient of a melanosome, and L_epi is twice the epidermal thickness.

This general scheme appears to work for probes of varying geometries. The details of the transport function will vary, but the general form is the same.

Hence, it is possible to specify meaningful parameters characterizing a tissue from spectra acquired with a simple optical fiber spectrophotometer.

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