Account of frequency dependence of the acoustic absorption coefficient in solving problems of acoustic-brightness thermometry

We perform a comparative analysis of the estimate bias in measuring the internal thermodynamic temperature and time of thermal destruction of biological tissue using the acoustothermometry method based on the model of recording of thermoacoustic radiation from a temperature-inhomogeneous medium with allowance for frequency dependence of the acoustic absorption coefficient. An expression for acoustic-brightness temperature is obtained in the case of reception of radiation by a broadband acoustothermograph. The possibilities of using the described method for determining the thermal destruction threshold of biological tissue under hyperthermia are studied. The parameter range in which frequency dependence of the acoustic absorption coefficient can be neglected is found. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 6, pp. 478–488, June 2006.