broader bandwidth are chosen to obtain high axial resolution. The lateral resolution is determined by the focal diameter of the transducer. For instance, a 50 MHz ultrasonic transducer provides 15 micrometre axial and 45 micrometre lateral resolution with ~3 mm imaging depth. Photoacoustic microscopy has multiple important applications in functional imaging: it can detect changes in oxygenated/deoxygenated hemoglobin in small vessels. Other applications Photoacoustic imaging was introduced recently in the context of artwork diagnostics with emphasis on the uncovering of hidden features such as underdrawings or original sketch lines in paintings. Photoacoustic images, collected from miniature oil paintings on canvas, illuminated with a pulsed laser on their reverse side, revealed clearly the presence of pencil sketch lines coated over by several paint layers. Advances in photoacoustic imaging Photoacoustic imaging has seen recent advances through the integration of deep learning principles and compressed sensing. For more information on the deep learning applications in photoacoustic imaging, see Deep learning in photoacoustic imaging. See also Multispectral optoacoustic tomography Photoacoustic microscopy Deep learning in photoacoustic imaging Photoacoustic effect References External links Recent advances in application of acoustic, acousto-optic and photoacoustic methods in biology and medicine Medical imaging