Fig. 2: Common PACT excitation and detection configurations.
From: Deep tissue photoacoustic imaging with light and sound
a PACT with a focused single-element transducer. By sweeping or scanning the single-element transducer, a synthetic 1D or 2D detection aperture can be made for 2D or 3D PACT, respectively. b PACT with a linear-array transducer, which allows for parallel detection of ultrasound along one dimension, providing real-time 2D imaging. c PACT with a full ring-array transducer. By providing surrounding ultrasound detection, limited-view artifacts are reduced. d PACT with a rotating half ring-array transducer, which can achieve a 4\(\pi\)-steradians detection coverage, making it a full-view detection method. e, f PACT with 2D transducer arrays such as the matrix-array (e) or the hemispherical-array (f), which can provide real-time 3D imaging by detecting along a 2D surface in parallel. g, h PACT with optics-based ultrasound detectors such as the micro-ring resonator (MRR) (g) or the Fabry-Perot interferometer (h), which can provide broad detection bandwidths, wide detection angles, and improved SNR compared with traditional piezoelectric-based transducers. Note that all detection configurations here can be translated or rotated to expand the effective detection aperture and field-of-view, at the expense of imaging time.
