Functional photoacoustic microscopy in vivo

Functional photoacoustic microscopy is a hybrid imaging technique that detects laser induced photoacoustic waves to image biological tissues in three dimensions. Its imaging depth exceeds the fundamental depth limit of the existing high resolution optical imaging modalities while maintaining a comparable ratio of imaging depth to axial resolution. The amplitude of photoacoutic waves is related to tissue's optical absorption and, therefore, functional imaging can be achieved by acquiring spectroscopic information. We demonstrate here the capabilities of functional photoacoustic microscopy by volumetric imaging a skin melanoma tumor and functional imaging of hemoglobin oxygen saturation in single vessels in vivo.