Abstract

Photoacoustic (PA) imaging using pump-probe excitation has been shown to detect fluorophores with high specificity. By varying the delay between the two excitation pulses and their wavelengths, the PA signal amplitude can be modulated, yielding three different and fluorophore-specific contrast mechanisms. In this study, PA images were obtained in tissue phantoms containing purified protein solutions using a ring array tomograph and a dual-OPO laser system. The results show that pump-probe excitation can detect multiple fluorescent reporters simultaneously. The method has the potential to recover biophysical parameters, such as pH and ion concentrations.

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