Potentialities of passive thermoacoustic tomography in hyperthermia

Abstract

The potentiality of passive thermoacoustic tomography (PTT) is considered theoretically. The problem is formulated to reconstruct the distribution of the thermodynamic temperature at a depth from the acoustic radiation generated by thermal noise and measured by a set of piezotransducers on the body surface. The 2-D inverse problem has been studied. Three mathematical methods of reconstruction were investigated: (1) the least squares method; (2) Tikhonov's regularization method; and (3) the method of elimination of non-physical solutions. The reconstruction in square as well as in rectangular areas was studied. If one uses the least squares method the square area can be separated into 5 5 subareas, the typical dimension of every one is 0.5-2 cm for measurements conducted in the frequency range 2-0.5 MHz. The precision deltaT in temperature reconstruction in different layers is about 0.1-0.2 K for smooth distributions of the thermodynamic temperature and 0.1-0.4 K for abrupt distributions, if the number of different scans is about 102 and the time of data collecting is about 1 min.

• Passive Tomography Non-invasive Thermometry Hyperthermia