1. A method of reconstructing a multi-dimensional data set representing a dynamic sample at a series of reconstruction instants, the multi-dimensional data set comprising a static component and a dynamic component, the method comprising: acquiring a plurality of projection images of the dynamic sample; reconstructing the static component of the multi-dimensional data set from the acquired projection images; acquiring a further plurality of projection images of the dynamic sample; and reconstructing the dynamic component of the multi-dimensional data set at each reconstruction instant from the further plurality of acquired projection images using a priori information about the dynamic sample, the multi-dimensional data set being the sum of the static component and the dynamic component at each reconstruction instant.