Evaluation of the spatial resolution of passive acoustic thermal tomography

Possible spatial resolution of a passive acoustic thermal tomograph is evaluated in numerical experiments. A criterion for the evaluation of this parameter is proposed. The criterion is based on the formation of a dip between two reconstructed temperature peaks with increasing distance between the thermal sources in the region under investigation. The spatial resolution depends on the positions of a pair of temperature peaks relative to the body surface and on the algorithm used for the reconstruction of the temperature distribution. An algorithm version providing an adequate reconstruction of the heights of the distribution peaks is suggested. It takes into account a priori information on the ultrasonic absorption coefficient and also the characteristics of the heat-transfer processes and the presence of blood circulation in a human body. In the case of lateral positions of the pair of temperature peaks relative to the surface, the spatial resolution is approximate to1.7 cm. The prospects for the improvement of the spatial resolution of a passive acoustic thermal tomographs are discussed. (C) 2002 MAN "Nauka/Interperiodica".