The present invention relates to X-ray generating technology in general. It is desirable to perform an X-ray image acquisition with a minimal required dosage for obtaining a desired image quality. Accordingly, a method for simulating reduction of acquisition dosage of an X-ray image, a computer system, an X-ray system, a computer-readable medium and a program element is provided. The method (30) for simulating reduction of acquisition dosage of an X-ray system comprises providing (32) first X-ray image information comprising first noise, the first X-ray image information having been acquired with a first dosage setting providing (34) a second dosage setting determining (36) a noise difference for obtaining simulated second X-ray image information acquired with the second dosage setting and applying (38) the noise difference to the first X-ray image information for obtaining the simulated second X-ray image information comprising second noise. The noise difference is at least partly dependent on at least one of a coloring of the first noise, a noise power spectra of the first noise, a coloring of the noise difference, a power spectra of the noise difference, an intensity distribution of the first X-ray image information and a local intensity distribution of the first X-ray image information.