Spatial-temporal correlations in the speckle pattern for the characterization of cellular motion within a 3D object.

Dynamic light scattering analysis has been demonstrated recently to be a promising tool for the assessment of structural changes taking place inside opaque tissue samples. Specifically, quantification of velocity and direction of cellular motion inside spheroids and organoids has attracted much attention as a potent indicator in personalized therapy research. Here, we propose a method for the quantitative extraction of cellular motion, velocity, and direction, by applying a concept of speckle spatial-temporal correlation dynamics. Numerical simulations and experimental results obtained on phantom and biological spheroids are presented.