Phase Velocity Dispersion Curve and Elastography Based on SAWs Induced by HIFU in Tissue Mimicking Phantoms

Surface acoustic waves (SAWs) is a non-invasive and nondestructive method to detect elastic property of materials in industrial and medical field. Elastography derived from SAWs has been proved to be efficient for reconstructing the elasticity distribution map. Current SAWs elastography applied in tissues provides lower lateral resolution as the SAW impulse was detected in larger distance interval (millimeter level). Therefore, a new protocol to form elastography with higher lateral resolution was proposed in this paper. Phase sensitive optical coherence tomography (PhS-OCT) with high spatial resolution was employed to monitor SAWs impulse stimulated by HIFU transducer. Tissue-mimicking phantoms were tested in this experiment. SAWs dispersion curve was retrieved through processing wave signal with 2D fast Fourier transform based algorithm. Consequently, elastography of double layered phantom was constructed by combining SAWs dispersion curve and specific penetration depth. The results revealed feasibility for HIFU transducer acting as an ideal stimulation source for SAWs, and the elastography performed higher lateral resolution than that of other SAWs elastography techniques. Thus, the method raised in this paper showed a significant potential to be utilized in the clinical for skin disease diagnosis and assist monitoring treatment efficacy.