Slit-based photoacoustic tomography with co-planar light illumination and acoustic detection for high-resolution vascular imaging in human using a linear transducer array.

Slit-based photoacoustic tomography is a high-resolution three-dimensional imaging technique for linear transducer array. The system was based on acoustic diffraction through a thin slit to increase the elevation coverage and spatial resolution. In this study, we introduce the third-generation slit-based photoacoustic tomography system with co-planar light illumination and acoustic detection. The new system possesses several innovations. First, we utilized an optically transparent slit, which enables both light illumination and acoustic diffraction. Second, we used a combination of cold and hot mirrors to provide co-planar light illumination and acoustic detection. Third, we designed a waterproof transducer array with a long acoustic focus tailored for the co-planar setup. Compared to the previous generations, which used side-illumination and metal slit, the new system provides a larger field of view and deeper imaging depth in a more compact manner. We tested the system in both phantoms and in vivo imaging. Detailed vascular structures from different regions can be clearly revealed, making the system valuable for translational imaging applications.