We present experiments designed to test the applicability of the frequency-domain semi-infinite multi-distance method to cylindrical boundaries. Material with absorption and reduced scattering coefficients similar to those of tissue exposed to nearinfrared light was cast into five cylindrical phantoms ranging in diameter from 4.2 to 10.2 cm, and also into a semi-infinite control. Measurements performed along the long axis of symmetry on the larger diameter cylinders reliably recovered both the absorption and the reduced scattering coefficients within 10% of the control values. Measurements performed along the circumference yielded values for these optical coefficients that differed significantly from the control values. These findings are explained by observing the measured frequency-domain parameters as functions of source-detector separation.

© 1996 Optical Society of America

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