Scalable magnetically mediated thermoacoustic imaging through coil tailoring

Microwave induced thermoacoustic imaging suffers limited penetration for high water content tissues and its system design is difficult to scale for different applications. To provide an alternative solution, magnetically mediated thermoacoustic imaging (MMTI) method is proposed here, which exploits alternating magnetic field of tens MHz to map the dielectric property of matter at ultrasonic resolution. Delivering energy via magnetic field emitting from a coil enables greater penetration as human body is non-magnetic and, the near field energy coupling nature further endows it with good scalability: by tailoring the coil, it allows the penetration and field of view to be scaled from imaging deep laid regions with large view to probing superficial ones within a small area. The coil design is thus critical for achieving scalable MMTI system, apart from affecting the system performance. We demonstrate here experimentally the signal generation performances of three different kinds of coils and showcase the scalable imaging capability of MMTI under two different scales. Furthermore, a 3 D imaging of a phantom using a small coil and mechanical scanning is presented.