Fig. 9.

a Illustration of the PLD based PA/PUS dual-modality system. Here PBS - phosphate-buffered-saline solution, PA - photoacoustic, and PUS - pulsed ultrasound. The imaging probe was positioned in the cross-section of the sample for PA imaging. b Pictures of histology sections and the corresponding cross-sections in overlaid PA/PUS images of plaques. Gray colour represents the ultrasound signals and overlaid red colour represent the PA signals. The red arrows indicate the blood content inside the plaques in the histology pictures and the corresponding PA signals in overlaid PA/PUS images. Reprinted from Ref [82]