Fig. 7.

Simulated (left column) and experimental (right column) PAT results for the described phantom: (a,i) Objects imaged by detector without an acoustic lens attached, (b,j) by detector with PMMA lens and (c, k) with Stycast 1090SI lens. Each image is normalized to its maximum intensity. (d, l) Axial intensity profiles along the trajectory indicated by dashed black line from (a)-(c). (e, m) Lateral intensity profiles indicated by dashed gray line from (i)-(k). (a)-(h) are simulation results, (i)-(p) are measurement results. Lateral resolution is improved by using both PMMA and Stycast lenses as expected, while axial resolution remains constant for all three cases. Due to limited bandwidth of the detector, ring-shape artifacts are presented around the objects. Those ring-shape artifacts are enhanced for objects imaged by detector with PMMA lens due to the ultrasound trapped inside the lens (indicated by arrows), while for the objects imaged by the detector with Stycast 1090SI lens, much weaker such artifacts are presented due to the tissue-like acoustic impedance of the lens material.