Recovery of layered tissue optical properties from spatial frequency-domain spectroscopy and a deterministic radiative transport solver

Abstract

We present a method to recover absorption and reduced scattering spectra for each layer of a twolayer turbid media from spatial frequency-domain spectroscopy data. We focus on systems in which the thickness of the top layer is less than the transport mean free path ð0.1 − 0.8l à Þ. We utilize an analytic forward solver, based upon the N'th-order spherical harmonic expansion with Fourier decomposition ðSHEF N Þ method in conjunction with a multistage inverse solver. We test our method with data obtained using spatial frequency-domain spectroscopy with 32 evenly spaced wavelengths within λ ¼ 450 to 1000 nm on six-layered tissue phantoms with distinct optical properties. We demonstrate that this approach can recover absorption and reduced scattering coefficient spectra for both layers with accuracy comparable with current Monte Carlo methods but with lower computational cost and potential flexibility to easily handle variations in parameters such as the scattering phase function or material refractive index. To our knowledge, this approach utilizes the most accurate deterministic forward solver used in such problems and can successfully recover properties from a two-layer media with superficial layer thicknesses.

Quantifying the confounding effect of pigmentation on measured skin tissue optical properties: a comparison of colorimetry with spatial frequency domain imaging

“…Many groups have taken significant strides in developing and applying such models, based in part on simulation. 15 , 24 – 26 , 29 , 31 , 32 Schmitt et al. used a layered diffusion model to simulate optical properties from a single point for a given source–detector separation.…”

“…detailed a method for measuring optical properties in a two-layered tissue-simulating phantom using an ’th-order spherical harmonic expansion with Fourier decomposition forward solver over a 450 to 1000 nm wavelength range. 32 Saager et al. used simulated optical property values generated through Monte Carlo modeling to build a two-layer model.…”

Quantifying the confounding effect of pigmentation on measured skin tissue optical properties: A comparison of colorimetry with Spatial Frequency Domain Imaging

“…Many groups have taken significant strides in developing and applying such models, based in part on simulation. 15,[24][25][26]29,31,32 Schmitt et al used a layered diffusion model to simulate optical properties from a single point for a given source-detector separation. 24 They used reference values for μ a and μ s 0 from previous reports to model the epidermis, dermis, and subcutaneous layers at 660 and 950 nm.…”

Dental lasers applications in visible wavelength operational band

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