This paper generalizes well-established derivations of the radiative transfer equation from first principles to model the energy density of time-dependent and monochromatic high frequency waves propagating in a random medium composed of localized scatterers. The correlation length of the random scatterers is small compared to the overall distance of propagation so that ensemble averaging may take place. The correlation length may be either comparable to the typical wavelength in the system (the weak-coupling regime) or larger than the wavelength (the low-density regime). The paper also considers the detection and imaging of inclusions buried in highly scattering random media. In such multiple scattering environments, the coherent wave fields may be too weak to be used for imaging purposes. We thus propose to model the inclusions as parameters in the macroscopic radiative transfer equations and consider the imaging problem as an inverse transport problem. Numerical simulations address ...