Abstract: The invention relates to a method and an apparatus for reconstructing a three-dimensional image volume from two-dimensional projection images of a subject which have been taken from different projection directions by rotating the recording system around the subject, wherein the grayscale values of the voxels of the image volume are calculated by back projection of the projection images. The invention is characterized in that prior to back projection at least one projection image is modified in such a way that it corresponds to a projection image taken with a virtual detector whose axes are aligned parallel to the rotational axis of the recording system.

Abstract: A method for determining an approximate value for a parameter characteristic of the fatigue state of a component as a result of a time-varying stress to which it is subjected by means of a number of load cycles should, itself, during comparatively lengthy stress cycles, enable a prognosis concerning the current fatigue state of the component, this prognosis being, in particular, adapted to the needs and suited for the real-time determination of maintenance intervals. To this end, in addition to optionally already fully completed load cycles, a first partially completed load cycle is also taken into consideration during the determination of the parameter, whereby temporary stress values for phases that have not yet been run through of the partially completed load cycle are, together with a predetermined fixed value, taken into consideration.