Real-time in-situ monitoring of electrotherapy process using electric pulse-induced acoustic tomography (EpAT)

The use of electrical energy in applying reversible or irreversible electropermobilization for biomedical therapies is growing rapidly. This technique uses an ultra-short and high-voltage electric pulse (μs-to-nsEP) to improve the permeability of cell membranes, thus allowing drug delivery to the cytosol via nanopores in the membrane. Since the treatment subject varies in size, location, shape and tissue environment, it is necessary to visualize this mechanism by monitoring electric field distributions in real-time. Previous studies suggested various techniques for monitoring electroporation, however, none of these techniques are so far capable for real-time monitoring of the electric field. In this study, we propose an innovative real-time, monitoring technique of electric field distributions based on electric field-induced acoustic emissions. For the first time, we demonstrate the capability of an electric field that used in electrotherapy to induce acoustic waves, which can be suggested for realtime monitoring. We tested this technique by generating a variety of electric field distributions (μs-to-nsEP with intensity up to 120V/cm) to energize two electrodes in a bi-polar configuration (d1=100μm and d2=200μm). The electric field transmits a short burst of ultrasonic energy. We used ultrasonic receivers for collecting acoustic signals around the subject under test. Acoustic signals were collected through different intensities of electric field distributions and repositioning the electric field from the receiver in 3D structure. An electric field utilized in electrotherapy produces high resolution images that directly can improve the efficiency of electrotherapy treatments in real-time.