In this report we present a scanning system and signal processing for three-dimensional strain mapping based on opticalcoherence tomography. This approach allows evaluating the tissue deformation in 3D for both quasistatic elastography(OCE) and monitoring of slowly relaxing strains (mechanical relaxations, creeps, etc.). Experimental demonstrations of3D OCE are performed using a silicone layer with known structure located on excised breast cancer tissue. It isimportant to note that in the described variant of OCE we perform aperiodic loading of the tissue not-synchronized withscanning. Because entire 3D datasets are acquired only twice (before and after deformation) it is crucial to ensure thatthere is already no tissue creep in the deformed state. Experimental demonstrations of monitoring of slow processes areperformed for visualization of cartilaginous-sample drying. Slow deformation may be undetectable on inter-B-scanintervals because such strain values may be well below minimal detectable level. However, for wider intervals (typicalfor 3D datasets acquisition), strains can attain an order of magnitude higher level that can be detectable and used forfurther calculations of relaxation parameters. We discuss the applicable scanning patterns and signal processingoptimizations.
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