NONUNIQUENESS IN DIFFUSION-BASED OPTICAL TOMOGRAPHY

A condition on nonuniqueness in optical tomography is stated. The main result applies to steady-state (dc) diffusion-based optical tomograph y, wherein we demonstrate that simultaneous unique recovery of diffusi on and absorption coefficients cannot be achieved. A specific example of two images that give identical de data is presented. If the refract ive index is considered an unknown, then nonuniqueness also occurs in frequency-domain and time-domain optical tomography, if the underlying model of the diffusion approximation is employed. (C) 1998 Optical So ciety of America.