14 July 2017 Determining the light scattering and absorption parameters from forward-directed flux measurements in cardiac tissue
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Abstract
We describe a method to accurately measure the light scattering model parameters from forward-directed flux (FDF) measurements carried out with a fiber-optic probe (optrode). Improved determination of light scattering parameters will, in turn, permit better modeling and interpretation of optical mapping in the heart using voltage-sensitive dyes. Using our optrode-based system, we carried out high spatial resolution measurements of FDF in intact and homogenized cardiac tissue, as well as in intralipid-based tissue phantoms. The samples were illuminated with a broad collimated beam at 660 and 532 nm. Measurements were performed with a plunge fiber-optic probe (NA=0.22) at a spatial resolution of up to 10  μm. In the vicinity of the illuminated surface, the FDF consistently manifested a fast decaying exponent with a space constant comparable with the decay rate of ballistic photons. Using a Monte Carlo model, we obtained a simple empirical formula linking the rate of the fast exponent to the scattering coefficient, the anisotropy parameter g, and the numerical aperture of the probe. The estimates of scattering coefficient based on this formula were validated in tissue phantoms. Potential applications of optical fiber-based FDF measurements for the evaluation of optical parameters in turbid media are discussed.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Anthony J. Costantino, Anthony J. Costantino, Christopher J. Hyatt, Christopher J. Hyatt, Michaela C. Kollisch-Singule, Michaela C. Kollisch-Singule, Jacques Beaumont, Jacques Beaumont, Bradley John Roth, Bradley John Roth, Arkady M. Pertsov, Arkady M. Pertsov, } "Determining the light scattering and absorption parameters from forward-directed flux measurements in cardiac tissue," Journal of Biomedical Optics 22(7), 076009 (14 July 2017). https://doi.org/10.1117/1.JBO.22.7.076009 . Submission: Received: 6 February 2017; Accepted: 15 June 2017
Received: 6 February 2017; Accepted: 15 June 2017; Published: 14 July 2017
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