There is provided the use of a low molecular weight thrombin inhibitor for the manufacture of a medicament for the treatment by dialysis, particularly haemodialysis, of a patient in need of such treatment, in which the thrombin inhibitor is provided in the dialysing solution, as well as dialysing solutions and concentrates including low molecular weight thrombin inhibitors, such as melagatran. The grooves are arranged diametrically oppositely on an outer circumferential region of the bearing bush. According to the invention, at least two reflecting polarizers are arranged in the light exit plane of the integrator in the same angular position relative to the axis of the integrator. The number of servo marks in the tone field of each servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position.