A read-out device reads out X-rays stored in phosphor layers. To improve image quality, the read-out device is controlled such that an X-ray of a first body part, e.g. of a limb, stored in a phosphor layer is read out by the read-out device controlled in a first read-out mode, and an X-ray of a second, different body part, e.g. of a thorax, stored in the phosphor layer is read out by the read-out device controlled in a second read-out mode. The scan parameters of the read-out device set in the first read-out mode are different from the scan parameters set in the second read-out mode in at least one scan parameter. The scan parameters include, but are not limited to, the size of the pixels, the intensity and/or the width of a focus range of stimulation light on the phosphor layer, the sampling rate of a detector, and a speed of the phosphor layer in relative movement to the read-out device.