The diffuse near infrared spectroscopy (DNIRS) and diffuse correlation spectroscopy (DCS) are the contemporary non-invasive optical methods which are now among the most required tools for assessing tissue health, in regards to mammography, brain, and particularly to pressure injuries and suspected deep tissue injury. We present results of numerical simulations of the photon diffusion and temporal correlations underlying these techniques in spatially restricted bio models containing static and moving scatterers. The calculations are performed for a tissue occupying a half-space as well as for multi-layered models, in particular for backscattering from a finite-thick scull layer localized above the semi-infinite brain model.