1. Apparatus for generating an image of a moving object, wherein a movement of the object comprises a plurality of moving phases, the apparatus comprising: a measured detection data providing unit ( 20 ) providing measured detection data of the moving object, which have been detected by using a detection process and which are assigned to the moving phases, a reconstruction unit ( 13 ) reconstructing an image object of the object from the provided measured detection data, wherein the image object represents at least a part of the moving object, an adaptation unit ( 18 ) for adapting the image object for different moving phases by adapting simulated detection data to the measured detection data of the respective moving phase, wherein the simulated detection data are determined by simulating the detection process, which has been used for detecting the measured detection data assigned to the respective moving phase, with the image object; wherein the measured detection data are measured projection data and wherein the adaptation unit ( 18 ) performs, for each moving phase, the steps of: simulating the detection process by forward projecting the image object, wherein simulated detection data are determined, determining a forward projected surface of the image object in the simulated detection data, determining a contour in the measured projection data by determining extremes of a gradient of the measured projection data, the extremes being determined along normals of the forward projected surface and form the contour, and modifying the image object to match the forward projected surface of the image object to the contour in the measured projection data.