Ultrasound imaging employs sound waves with frequencies >20 kHz. These waves are pulsed through internal structures and the resulting ‘echo’ is used to generate an image of the internal structures. Optoacoustic or photoacoustic imaging is an imaging technique which detects ultrasound waves following light absorption from specific molecules. This technique allows molecules with different spectral profile to be detected. Advancements in the development of nanoparticles and infrared fluorescent reporters that are detectable by optoacoustics have also increased the possibilities of molecular imaging.