Unified linear-concave transducer enabling 100 Hz plane-wave ultrasound and photoacoustic dynamic imaging.

Dual-modal ultrasound (US) and photoacoustic (PA) imaging with linear-array transducers offers clinically relevant imaging depths and flexible access to anatomical sites, while enhancing optical contrast. By integrating anatomical detail from US with the molecular specificity of PA, this approach provides complementary information that supports more accurate and comprehensive diagnostics than either modality alone. Despite its promise, high-quality video-rate dual-modal imaging remains hindered by two longstanding challenges. Conventional linear-array transducers, optimized for US by suppressing grating and side lobes, inherently limit the wide field of view (FOV) and broad fractional bandwidth necessary for effective PA detection. In contrast, concave arrays extend the FOV for PA but introduce substantial grating artifacts in US imaging, compromising structural fidelity. To overcome these constraints, we engineered a unified linear-concave transducer (ULC-T) that enables synchronized video-rate (100 Hz) plane-wave US and multispectral PA imaging on a standard 128-channel acquisition platform. The ULC-T integrates linear and concave segments into a unified array architecture. A spatial correction algorithm compensates for segmentation misalignments, reducing fabrication constraints, while a customized transmit-receive scheme enhances imaging performance. Validated across phantom, small animal, and human studies, the system demonstrates high imaging speed and deep tissue penetration, offering a practical solution to persistent dual-modal integration challenges and showing strong potential for clinical translation.