Time-division multiplexed microwave-induced thermoacoustic and ultrasound tomography for complementary structural and dielectric imaging

Simultaneous acquisition of high-resolution anatomical and high-sensitivity dielectric-contrast information remains a fundamental challenge in biomedical imaging. Here, we propose a bimodal tomography approach that integrates microwave-induced thermoacoustic imaging (MTAI) and ultrasound imaging (USI) via a time-division multiplexing synchronization strategy. This method enables co-registered, real-time dual-modality imaging using a shared semicircular transducer array. Both modalities achieve submillimeter spatial resolution and maintain favorable signal-to-noise ratios across the field of view. We validate the system on ex vivo tissues, living small animals, and human digits. USI delivers precise anatomical localization, while MTAI provides high-contrast mapping based on intrinsic dielectric properties, together offering remarkable complementarity. This integrated structural–dielectric imaging strategy holds strong potential for biomedical diagnosis and physiological monitoring.