Prospects of microwave-induced thermoacoustic imaging

Microwave-induced thermoacoustic imaging (MTAI) has advantages including the large imaging depth, high imaging resolution, high imaging contrast, and fast imaging speed. The thermoacoustic (TA) group of South China Normal University has dedicated to developing TA imaging for more than a decade and has made many breakthroughs. This review introduces these breakthroughs from two aspects including the improvement in techniques and the exploration of applications. On the technological level, there are ultrashort microwave pulse (USMP)-induced TA imaging that can improve the imaging resolution, nonlinear thermoacoustic imaging (NTAI) that can improve the imaging contrast, polarized microwave-induced thermoacoustic imaging (P-MTAI) that can obtain cellular-level alignment information, and more convenient and accurate handheld and multimodal probes. On the application side, the optimization and expansion have been carried out, mainly concentrating on breast and myocardial imaging. Finally, several current research directions are introduced, including the application of P-MTAI on joint imaging and research on whole-body imaging of small animals.