An envelope of a voltage may be extracted using an operator to calculate a position and speed of a rotor. Substantially, the entire medium is scanned by X-ray beams, and the X-rays passing through the medium are detected for a plurality of areas of the medium. The invention further relates to methods for treating the side-effects of inhibitors of nucleic acid biosynthesis or their precursors using the aforementioned active ingredients, in particular pyrimidine nucleosides andor prodrugs produced therefrom, or the aforementioned combinations or products and to corresponding pharmaceutical preparations. Filtering can also be implemented on the antenna structure.