Quantitative photoacoustic imaging utilizing a reference absorber as a fluence marker

Accurate characterization of carotid plaque composition is essential to identify vulnerable plaque that often leads to stroke. Photoacoustic imaging, which combines optical absorption contrast with ultrasonic imaging depth, shows promise for quantitative examination of carotid plaque. However, unknown light fluence in the tissue makes quantitative photoacoustic imaging challenging. We propose utilizing a known chromophore as a light fluence marker. The feasibility of the approach was tested using simulations on digital phantoms and experiments using tissue-mimicking phantoms. The results show agreement with the actual concentrations, supporting our hypothesis. We intend to extend the approach to ex vivo plaque imaging.