Imaging through highly scattering human skulls with ultrasound-modulated optical tomography

Advances in human brain imaging technologies are critical to understanding how the brain works and the diagnosis of brain disorders. Existing technologies have different drawbacks, and the human skull poses a great challenge for pure optical and ultrasound imaging technologies. Here we demonstrate the feasibility of using ultrasound-modulated optical tomography, a hybrid technology that combines both light and sound, to image through human skulls. Single-shot off-axis holography was used to measure the field of the ultrasonically tagged light. This Letter paves the way for imaging the brain noninvasively through the skull, with optical contrast and a higher spatial resolution than that of diffuse optical tomography.