In vivo three-dimensional photoacoustic tomography of a whole mouse head

An in vivo photoacoustic imaging system was designed and implemented to image the entire small animal head. A special scanning gantry was designed to enable in vivo imaging in coronal cross sections with high contrast and good spatial resolution for the first time to our knowledge. By use of a $2.25\mathrm{MHz}$ ultrasonic transducer with a $6\mathrm{mm}$ diameter active element, an in-plane radial resolution of $\sim 312\mu \mathrm{m}$ was achieved. Deeply seated arterial and venous vessels in the head measuring up to $1.7\mathrm{cm}$ in diameter were simultaneously imaged in vivo with $804\mathrm{nm}$ wavelength laser excitation of photoacoustic waves.