Abstract: The invention relates to a method and a device for the iterative reconstruction of cross-sectional images of the heart (7) of a patient based on projections (P1, . . . P5) from different directions which are for example generated with a helical cone-beam CT scanner. A cardiac weight function (f) quantifies how near the projections (P1, . . . ) are to a given observation phase (To) of the heart cycle based on simultaneously recorded electrocardiographic signals (ECG). The whole set of projections (P1, . . . ) is divided into subsets (S1, . . . ) which each contain only projections corresponding to a similar cardiac weight (f), and an iterative reconstruction algorithm like ART uses in one update or iteration step all projections of such a subset (S1, . . . ) simultaneous].

Abstract: The invention relates to a device and a method for the iterative reconstruction of the attenuation coefficients ?j in a tomographic image of an object (1) from projection measurements mi. In the update equation for ?jn during the n-th iteration the backprojected error (mi?mi?(?jn)) is weighted by a voxel dependent factor Formula (I). Such a voxel dependent update may particularly be included in the algorithms of ART or ML.

Abstract: The invention relates to an examination apparatus with an X-ray device (10) for circular or helical cone-beam CT acquisition of projections images (Pi(E1), Pi(E2)) of a patient (1) with different energy spectra (E1, E2) and/or with an energy-resolved detection. By a combination of the projections, images (Ibone,i, Itissue,i) can be calculated that show predominantly the bone structure and the soft tissue, respectively. Therefore, a 3D model (Mbone) of the bone structure and a 3D model (Mtissue) of the tissue can be reconstructed separately. After removal of artifacts from the bone-structure model (Mbone), both separate 3D models can be integrated to a combined model (M) of the body volume with a high image quality.

Abstract: A computer tomography apparatus (100) for examination of an object of interest (107), the computer tomography apparatus (100) comprising detecting elements (123) adapted to detect electromagnetic radiation coherently scattered from an object of interest (107) in an energy-resolving manner, and a determination unit (118) adapted to determine structural information concerning the object of interest (107) based on a statistical analysis of detecting signals received from the detecting elements (123).

Abstract: The invention relates to a computer tomography method with a circular relative movement between the beam source and an iterative reconstruction method suitable therefor. The reconstruction method is substantially improved by deriving the first approximation image from a CT image, which is obtained from a prior acquisition during helical relative movement.

Abstract: The reconstruction of images of an object of interest may introduce artifacts along lines of high gradients of absorption values. According to an exemplary embodiment of the present invention, these artifacts may efficiently be removed by a statistical weighing during reconstruction of the image. Advantageously, according to an aspect of the present invention, the reconstruction of the image may be performed iteratively, wherein the updates are weighted with the intrinsic statistical error of the measured photon counts. This may lead to an efficient removal of artifacts.