7. Conclusions

Previous page | Table of Contents

(1) An axial scan of a homogeneous tissue by a confocal microscope yields experimental data that behaves as a single exponential: ρ exp(-μ z_f).

(2) The values of ρ and μ uniquely map to a pair of optical property values, μ_s and g. Such confocal reflectance measurements allows separate meaurement of these two properties rather than measurement of the lumped parameter μ_s' = μ_s(1-g) as is obtained with optical measurements based on multiply scattered light in the diffusion regime (where photons move down concentration gradients).

(3) The variety of mouse tissues examined showed values of μ_s for the 488 nm wavelength of these experiments to be in the range of 300-600 cm^-1. The values of g varied quite strongly (0.90-0.99) and demonstrated a strong effect on the confocal signal.

(4) This work is preliminary and there is still room for adjustments in the analysis.

• Our current work is pursuing the behavior of the analysis grid using Monte Carlo simulations which should improve on the approximate analytic expression used in this report.
   
• More work is in progress on calibrating the system with polystyrene microspheres of various sizes.
   
• The assumption of tissue homogeneity is another factor that can frustrate such experiments. But we note that analyzing the average behavior of an ensemble of neighboring pixels versus depth appears to overcome the effect of small scale heterogeneities.

(5) There is great opportunity in using anisotropy as a contrast agent since g is sensitive to the apparent particle size of scatterers that characterize the ultrastructure of a tissue (nuclei, mitochondria, collagen fibers, etc.).

Previous page | Table of Contents