In a method for reconstructing a three-dimensional subject a number of projections of a three-dimensional subject is acquired by an acquisition arrangement. Each projection is a dataset of spatially contiguous data values. The projections are provided to a computer. A first part of the data values of the projections is replaced by new data values, and a second part of the data values of the projections remains unchanged. Thus changed projections are generated, using which a reconstruction of an image of the subject is determined by the computer.