4. Experimental Results

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The experimental results are shown for 5 mouse tissues and a gel with polystyrene microsphere:

  • brain (white matter)
  • brain (gray matter)
  • skin
  • muscle
  • liver
  • 0.1-μm-dia. polystyrene microspheres (μs = 97 cm-1, g = 0.11)

As the scattering becomes stronger and more backward directed, both the reflectivity (ρ [dimensionless]) and the attenuation (μ [cm-1]) increase. It makes sense that if more light is backreflected, less light can transmit to be scattered by deeper depths, hence the attenuation increases.

To cause a comparable change in observed backreflected confocal SIGNAL, either a comparable change in A may occur, or a much smaller change in μ can occur since μ is in the exponent of the expression ρ exp(-μ zf). So it is not suprising to see the roughly linear relation between μ and log(ρ) in the data shown.

SIGNAL(zf) = ρ exp(-μ zf)
ρ [dimensionless] = reflectivity (x axis),
μ [cm-1] = attenuation (y axis)

(click on figure to expand)

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