PREPARATION OF SOLID PHANTOMS WITH DEFINED SCATTERING AND ABSORPTION PROPERTIES FOR OPTICAL TOMOGRAPHY

We have developed diffusely scattering solid phantoms with optical (sc attering) properties amenable to theoretical calculations. Monodispers e quartz glass spheres were used as scatterers embedded in polyester r esin. An infrared dye was added to simulate absorption by biological t issue. Solid phantoms were tested for their macroscopic homogeneity. S everal phantoms were built with well-defined spatial variations in the ir transport scattering and absorption coefficients to be used for opt ical tomography. Scattering, transport scattering, and absorption coef ficients of solid, homogeneous phantoms and of aqueous suspensions of monodisperse quartz glass spheres were derived from measurements of ti me-integrated collimated transmittance and time-resolved diffuse trans mittance. For aqueous suspensions of monodisperse quartz glass spheres at known number density scattering and transport scattering coefficie nts calculated by Mie theory are in quantitative agreement with experi mentally derived values. In addition, diffuse reflectance and diffuse transmittance of aqueous suspensions at various number densities were measured and found to be in excellent agreement with results of Monte Carlo calculations using theoretical values for the scattering coeffic ients and anisotropy parameters.