Optical Coherence Tomography Detection of Shear Wave

In this work, we explored the potential of measuring shear wave propagation using Optical Coherence Elastography (OCE). Shear waves were generated using a 20 MHz piezoelectric transducer transmitting sine-wave bursts of 400 μs, synchronized with the OCT swept source wavelength sweep. The acoustic radiation force was applied to two gelatin phantoms (differing in gelatin concentration by weight, 8% vs 14%, respectively). Differential OCT phase maps, measured with and without the acoustic radiation force, demonstrate microscopic displacement generated by shear wave propagation in these phantoms of different stiffness. The shear wave speeds for the 14% and 8% gelatin-titanium dioxide phantoms were 2.24 0.06 m/s and 1.49 0.05 m/s and also the shear modulus estimated using SW-OCE was 5.3±0.2 kPa and 2.3±0.1 kPa for the 14% and 8% gelatin-titanium dioxide phantoms, respectively. The results demonstrate the feasibility of this technique for measuring the mechanical properties of tissue.