The photoacoustic effect in which sound is generated due to absorption of light by a material provides access to a type of medical imaging with unique characteristics. These images can represent both physiological events in the body, indicating the molecular composition of tissue, and are usually coupled to the anatomical images from ultrasonography. The use of photoacoustic images has proved effective in identifying tumors, atherosclerotic plaque, tissue microvasculature, among others.

More information at Pavan, TZ; Carneiro, AAO; Emelianov, SY Photoacoustic: images of the interaction of light and sound on the human body. Science Today, vol. 50, p. 38-42, 2012