input parameters are necessary e g geometry parameters 26 including several geometrical parameters for example zoom of the acquired image the angulation and rotation angles of the c arm 10 and other geometrical parameters are provided additionally anatomy priors 28 are further provided as input parameters for ideally taking anatomical and prior interventions into account also shutter parameters 30 containing the shutter position the shutter size and the shutter shape is provided as still further input parameters for the geometry generation the shutter blocks x rays before reaching the patient to be examined in order to limit the x ray exposed area of the patient since outside of shutter borders no x ray detection is possible the presence of the considered targeted object in the live images may be blocked by the shutter and thus the shutter position the shape and the size must be taken into consideration the shutter parameters 30 and the geometry parameters 26 may be provided through system information 32 wherein the calculation unit 18 or any other device provides all relevant measured or stored information about the related x ray image acquisition device and of the medical viewing system the geometry generation may include the generation.