Abstract

Local optical properties of a biological tissue, like its absorption coefficient, can yield valuable information for medical diagnosis. Extracting such information from deep inside the tissue is, however, a challenging task, due to strong light scattering, resulting in low-resolution image at depths larger than a few mm. Combining optical imaging with ultrasound (US) – the latter propagating ballistically inside the tissue, is a promising approach to solve this problem. There is indeed the example of photoacoustic imaging - where one collects US generated following light absorption to map the absorption coefficient, with successful clinical trials. Concurrently, ultrasound-modulated optical tomography (UOT) - where one collects the light scattered due to the propagation of US in the tissue (“tagged light”), can also be used to perform deep-tissue imaging. However, due to a poor signal-to-noise ratio (SNR), the latter is yet to be tested on an in vivo subject.

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