Transient optoelastography in optically diffusive media

The authors present a camera-based optical detection scheme designed to detect the transient motion created by the acoustic radiation force in soft elastic media. An optically diffusive tissue-mimicking phantom was illuminated with coherent laser light, and a high speed camera (2kHz frame rate) was used to acquire and cross-correlate consecutive speckle patterns. Time-resolved transient decorrelation of the optical speckle was measured as the result of localized motion induced by the radiation force and the associated propagating shear waves. The proposed technique is sensitive only to the low frequency transient motion induced in the medium by the radiation force.