Fig. 4.
(a) Schematic of 128-element hemisphere array-based PAT.52 The pulsed laser beam was expanded by a concave lens at the bottom of the imaging bowl, and then irradiated on the object. 128 single transducers were spirally located on the hemispherical surface to collect PA signals. (b) Lateral MIP image of a human breast using hemisphere array PAT.53 (c) Anterior–posterior MIP image of the human breast using hemisphere array PAT.53 Image area: ~9 × 9 cm2.