Low-cost fast photoacoustic computed tomography: phantom study

Photoacoustic tomography (PAT) is an emerging modality for imaging living biological tissue. Being label free, non-invasive, and having comparable resolution to ultrasound, PAT has many medical translations. This paper demonstrates our development of a low-cost 16 element transducer array for rapid imaging (1 frame per second) of biological samples. For the first time we demonstrate quality images obtained with a completely low-cost system. A rotatable platform houses our 16 equidistant Technisonic transducers, which is rotated 22.5° to acquire a full 360° field of view. We use Ekspla NL200 series Q-switched laser at 532 nm illumination wavelength with coupled optical fiber for overhead illumination. Our transducers send data to a National Instrument data acquisition system, triggered by the previously mentioned laser for efficient detection of photoacoustic signal. We have characterized this system through the imaging of complex optical absorbing lead phantoms. Thin lead has been imaged to demonstrate the spatial resolution of the system using the point spread function. Characterization of this system will allow us to move to ex-vivo imaging. We aim to develop this system as a platform for quality small animal functional brain imaging.