Frequency-dependent diffusion inside (A) the intracellular space for various cell radii (numerical calcul, Rcell = 1/4/10 μm, blue/green/black circles) and (B) extracellular space in the long / intermediate / short time regime. A. Oscillation frequencies fOGSE in the range [0–225] Hz are best suited to detect time-dependent changes from the intracellular compartment in cancer cells (Rcell = 4 μm). B. The analytical expression for diffusion in the ECS in the intermediate time domain is in general unknown (second column). Outside the short-time regime (i.e. within the grey area), small time-dependent variations are expected from the extracellular compartment (double arrow), compared to intracellular diffusivity changes inside cancer cells (Fig. 1A, green).