Applied current thermoacoustic imaging for biological tissues.

BACKGROUND: The large differences of electrical characteristics can be used to reflect the physiological and pathological changes about biological tissues, and it can provide evidence for the early diagnosis and treatment of cancer in potential applications. OBJECTIVE: This paper describes a method called Applied Current Thermoacoustic Imaging (ACTAI) and explores the theory and demonstrates a low conductivity numerical simulation and fresh pork experimental studies. METHODS: In this paper, firstly, the principle of ACTAI is studied. In ACTAI, a target is applied with a microsecond width Gaussian pulse current. Then the target absorbs Joule heat and expands instantaneously, sending out thermoacoustic waves. The waves contain the conductivity information of the target. The waves received by sound transducers are processed by the time inversion method to reconstruct the sound source distribution of the target to illustrate the conductivity information of the target. Secondly, a square model with low conductivity was used as a target to conduct numerical simulation of ACTAI. Lastly, a fresh pork experiment study was conducted. RESULTS: The presented experimental results suggest that ACTAI can identify the conductivity changes information of the target with perfect imagery contrast and deep penetration. CONCLUSION: The ACTAI modality would benefit from the noncontact measurement and can be convenient for clinical application.