Fig. 1. (Color online) MC light transport model for an artificial blood vessel. The target location and beam pattern are at the (a) longitudinal and (d) tangential direction. The corresponding fluence distribution and the absorbed energy density are (b, c) along the x–z slice (y=0  cm) and (e, f) at the y–z slice (x=0  cm).

Fig. 2. (Color online) Numerical simulation configurations (a) x–z and (b) y–z direction of the PA wave propagation and detection.

Fig. 3. (Color online) Conventional BP reconstructed PA images (a) and (c), and conventional BP reconstructed PA images (b) and (d) with the fluence compensation from the MC light transport model.

Fig. 4. PAT setup based on the linear array transducer.

Fig. 5. (Color online) Phantom study of an artificial blood vessel. (a) The photograph of the phantom. (b) The fluence map at the axis view. (c) and (d) are the co-registered US and PA images separately recovered from the BP and the fluence-compensated BP method. (e)–(g) are the results in the same order at the lateral view.

Fig. 6. (Color online) In vivo study of a human forearm vessel. (a) The photograph of the vessel. (b) and (d) are the co-registered US and PA images separately recovered from the BP and the fluence-compensated BP method. (c) The fluence map at the axis view. (e)–(g) are the results in the same order at the lateral view.