Amplitude characteristics of microwave induced thermoacoustic signals

When pulsed radio-frequency (RF) or pulsed microwave irradiation is absorbed by biological tissue, the expansion of the heated tissue, derived from the absorption of electromagnetic energy, leads to an instantaneous acoustic stress or pressure distribution inside the tissue, which prompting wave propagation toward the surface of the tissue. In this paper, we present a theoretical analysis of the amplitude characteristics of microwave induced thermoacoustic (MITA) signals based on the thermal equation and dynamical equation. Then a brief introduction to the prototype of MITA tomography experimental system is given. And two groups of experiment have been carried out. The experimental results are used to validate the theoretical analysis and also may be employed to evaluate the limitation of microwave power for safety reasons as well as the availability of signals for reconstruction.