Microwave Thermoacoustic Imaging (MTAI) is an exciting imaging technique rooted in the underlying principle of exploiting the distinct electrical properties of biological tissues. By harnessing short-pulsed microwaves as a stimulation source and leveraging their interaction with the human body, MTAI has paved the way for revolutionary advancements in medical imaging. When microwaves are absorbed by polar molecules and ions within the tissues, an ingenious thermoelastic effect gives rise to ultrasound waves. These ultrasound waves, brimming with invaluable pathological and physiological insights, propagate outward, carrying the essence of the biological tissue's composition and functionality. Through a meticulous collection of ultrasound signals from all directions surrounding the tissue, it becomes possible to reconstruct intricate internal structures and visualize the tissue's functional dynamics. MTAI excels in non-invasiveness, capable of delving several centimeters beneath the surface with a microscopic resolution on the order of micrometers. The magic lies in the transformative conversion of microwave energy into ultrasound waves, tapping into the tissue's hidden depths without causing harm. This groundbreaking imaging modality unlocks a realm of possibilities for acquiring profound insights into the intricate structures and functionality of deep-seated tissues. Furthermore, the inherent polarization characteristics of microwaves empower MTAI to capture additional dimensions of information, unraveling the intricate polarization properties and illuminating a richer understanding of the tissue's complexity. The immense potential of MTAI extends far and wide within the realm of medicine. It has already demonstrated remarkable achievements in non-invasively imaging brain structures, screening for breast tumors, visualizing arthritis in human joints, and detecting liver fat content. These accomplishments have laid a solid foundation, firmly establishing MTAI as a trailblazing medical imaging technique. This article offers a comprehensive and in-depth exploration of the physical principles underpinning MTAI, the sophisticated system devices involved, and the recent groundbreaking research breakthroughs. Moreover, it delves into the exciting prospects and challenges that lie ahead in the future development of MTAI. As the technology continues to progress by leaps and bounds, MTAI is poised to shatter barriers, ushering in a new era of unrivaled imaging quality and performance. This, in turn, will open the floodgates for transformative innovation and application in the realms of medical diagnosis and treatment. The anticipation is palpable as MTAI strives to make substantial contributions to the ever-evolving field of medical imaging, bestowing upon humanity more precise, reliable, and life-enhancing diagnostic capabilities.
