Abstract: A multi-emitter computed tomography scanner is disclosed, including a plurality of x-ray emitter/detector arrangement pairs arranged offset at an angle to one another. In at least one embodiment, the detector arrangements of the pairs are designed to be energy selective.

Abstract: A method and a CT system are disclosed for measuring the perfusion in vessels and/or muscles of the heart (cardiac perfusion) in a patient. In at least one embodiment of the method the patient receives a contrast agent bolus, the patient is scanned for a scan period of a plurality of cardiac cycles in a scan field of a CT system controlled by the cardiac rhythm, a plurality of CT image data is reconstructed from projection data of a particular cardiac phase from respectively one cardiac cycle, and the temporal profile of the absorption values at at least one location in the heart is determined and displayed on the basis of a plurality of CT image data at successive times.

Abstract: A method is disclosed for generating computer tomography images using a 3D image reconstruction method. According to the method, to scan an object to be examined using a cone-shaped bundle of rays originating from a focal point and a planar, preferably multi-line detector for detecting the bundle of rays, the focal point is displaced along a spiral trajectory around the object to be examined. The detector delivers output data corresponding to the detected radiation and image voxels from the scanned examined object are reconstructed from the optionally pre-processed output data, the image voxels reflecting the attenuation coefficients of the respective voxel. Each image voxel is reconstructed separately from projection data, which covers a projection angular range of at least 108° and an approximate weighting is carried out for each voxel considered in order to standardize the projection data using the voxel.

Abstract: An X-ray detector is disclosed for detecting individual quanta. In at least one embodiment, the X-ray detector includes a plurality of detector elements and an evaluation unit that is connected to the latter for data purposes and is set up in such a way that each detector element is assigned a first energy threshold, wherein in each case one portion of various radiation spectra that can be picked up by the detector element exhibits an energy below the energy threshold, and a further portion of the respective radiation spectrum exhibits an energy above the energy threshold.

Abstract: A method is proposed for correcting detector signals of a unit for reconstructing tomograms from projection data, in particular of a computer tomography unit, of a ray detector having a multiplicity of individual detector channels that form the projection data, attenuation values of individual X-rays being calculated after the passage through an examination object. In order to reconstruct the tomograms from attenuation values of the X-rays, the detector output signals are subjected to a nonlinearity correction before the calculation of the attenuation values.

Abstract: A method is for taking computed tomography scans with the aid of a CT unit and to a CT unit. An X-ray tube is moved in a circle or spiral about a z-axis in combination with a detector situated opposite and an object is scanned. The X-ray tube includes a jumping focus with two or more different jumping focal positions relative to the X-ray tube. Parallel data records are formed from the detector data obtained, and tomograms are reconstructed therefrom. When forming the parallel data records, account is taken of the different position of the respectively current jumping focus in relation to the X-ray tube (=jumping focal position) in the radial direction.

Abstract: A shadow mask and method for adjustment are disclosed. The shadow mask may be for an X-ray detector including detector elements, which may further be provided for a computed tomography unit, for example. The shadow mask has a mask plate with holes of which each is assigned a detector element. At least one adjusting hole of the mask plate includes enlarged dimensions in such a way that it is adapted to the dimensions of at least two detector elements. The adjusting hole serves for the method of adjusting the shadow mask over the X-ray detector. Measurement signals of the detector elements that are assigned to the at least one adjusting hole, are determined by using X-radiation. The shadow mask and the X-ray detector are adjusted relative to one another on the basis of a comparison of the measurement signals of the detector elements.

Abstract: The image reconstruction is implemented along theoretical ?-lines, wherein the theoretical ?-lines not only lead to interpolated detector data but also can emanate from interpolated source positions. Interpolation thus occurs both at the detector and at the source.

Abstract: An x-ray system is disclosed including a selector for finding an optimum combination between the contrast medium and the energy spectrum of an x-radiation for a scan to optimize the noise-to-contrast ratio. A method for creating X-ray images is also provided. The x-ray images are created with the aid of contrast media by taking into account an optimal combination between the contrast medium and the energy spectrum of an X-radiation used for a scan. A method for the use of a lanthanide-containing complex to produce a contrast medium for optimizing the combination between the contrast medium and the radiation to obtain a maximum contrast-to-noise ratio in an X-ray image is also provided.

Abstract: A method is disclosed for scattered radiation correction in an X-ray computed tomography system having at least two tube-detector systems. It is provided, according to at least one embodiment, to make use of a data record that includes data projections required for the reconstruction and a prescribed number of first scattered radiation projections. Respective scattered radiation components for the scattered radiation correction of all data projections are determined on the basis of the first scattered radiation projections and second scattered radiation projections determined therefrom.

Abstract: A method is for recording and evaluating image data with the aid of a tomography machine. At least two recordings with different spectral distribution are made of an examination area of an object. Further, measured data obtained from the two recordings are evaluated such that additional information relating to the examination area and/or a specific representation of the image of the examination area are/is obtained from the different spectral distributions. The tomography machine includes at least two separate recording systems. Further, it is operated such that the two recording systems operate with a different spectral distribution. As such, the additional information and the specific representation of an image can be obtained in conjunction with a reduced scanning time.

Abstract: An imaging method is disclosed for variable pitch spiral CT. In at least one embodiment, the method includes spiral scanning of an examination object lying on a patient table, with the aid of a beam emanating from at least one focus, and the aid of a detector arrangement of planar design lying opposite the focus, the detector arrangement supplying output data that represent the attenuation of the beams during passage through the examination object; filtering the output data; weighted back projection of the filtered output data; and visualizing a layer or a volume on a display unit on the basis of the back projected output data. In at least one embodiment, a non constant pitch of the spiral scanning is taken into account computationally during the back projection. In at least one embodiment, a CT machine is disclosed for carrying out the above named method.

Abstract: A method is disclosed for reconstructing a tomographic representation of an object from projection data off a moving radiation source through this object onto a detector, filtering and back projection of the projection data being executed in the reconstruction. In an embodiment of the method, by using at least one identical spatial arrangement of the radiation source, the detector and a test object instead of the object to be scanned, there is determined by test projections and an iterative reconstruction technique, a filter that in the given arrangement results in an optimum filtering and back projection of the projection data of the test object for the tomographic representation. Further, the object is scanned instead of the test object in the given arrangement and projection data are determined. Finally, the reconstruction of the tomographic representation is carried out using these projection data and the filter determined.

Abstract: It is proposed to estimate the scattered radiation on the basis of a sinogram, which is measured in any case. In at least one embodiment, a method includes determining the potential scattering site for each measuring beam from the object tangents in the sinogram and calculating the scattered intensity from the primary radiation striking the scattering site and the angle ratios of scattering beam, object tangent and measuring beam. Also proposed, in at least one embodiment, is an X-ray CT having at least bifocal detector systems and a control and computer unit for producing tomographic pictures, the control and arithmetic unit of which contains a program code that, upon being executed, carries out the method.

Abstract: In a method and filter and computer product for adaptive filtering of projection data acquired by a medical diagnostic apparatus, raw data-based filtering of the acquired projection data is undertaken using a filter with a filter kernel having a constant filter width, and the filtered projection data are mixed with the acquired projection data with a fixing of the respective quantitative relationships of filtered projection data to acquired projection data ensuing dependent on respective subsets of the acquired projection data.

Abstract: A method for scattered radiation correction of a CT system, including at least two focus/detector systems operated angularly offset from one another, is disclosed. In the method, at at least one phantom, similar to the examined object at least in a subregion, for at least one of the focus/detector systems, the scattered radiation intensity occurring is determined in the detector of a focus/detector system during the operation of the at least one focus of at least one other focus/detector system. Further, the spatial distribution thereof is stored for a number of angles of rotation of the focus/detector systems. During scanning of the object, the scattered radiation intensities, determined with the aid of a similar phantom that originate from the at least one other focus/detector system, are subtracted from the measured intensities of the first focus/detector system while taking account of the spatial orientation of the focus/detector systems and the beam respectively considered.

Abstract: A method is disclosed for scattered radiation correction in x-ray imaging devices having a number of x-ray sources that can be moved around an examination object in at least one scanning plane during a measurement pass. During the measurement pass, a number of x-ray projections are recorded at different projection angles with simultaneous use of the x-ray sources. In at least one embodiment of the present method, parameters characterizing an outer object contour are determined in the scanning plane from measured data of different x-ray projections.

Abstract: A method is disclosed for scattered radiation correction in X-ray imaging, and an X-ray imaging system is disclosed for carrying out the method. In at least one embodiment of the method, measurement signals t from an X-ray detector are digitized and converted to logarithmic form, with these measurement signals t having been obtained by radiation through an examination object by the X-ray detector. Correction values which have been obtained from a series development of a logarithm 1n(1?s/t) are subtracted from the measurement signals that have been converted to logarithmic form, with this series development being terminated at the earliest after the first order, where s denotes a previously determined scattered radiation signal from radiation passed through the examination object. At least one embodiment of the method and the associated X-ray imaging system allow scattered radiation to be corrected for with increased accuracy, on the basis of measurement signals that had been converted to logarithmic form.

Abstract: Incomplete data records owing to an object extent that stretches beyond the scanning field of view (SFOV) constitute a general problem in computed tomography. In these cases, parts of the object are to be reconstructed, for which only incomplete projections from an angular range of less than 180° are available. The application of iterative algorithms such as, for example, the algebraic reconstruction technique (ART) or the simultaneous algebraic reconstruction technique (SART) to this problem of truncated projections cannot lead to a satisfactory solution unless use is made of special boundary conditions. In order to regularize the reconstruction method, in at least one embodiment, information relating to the statistics of the attenuation values of the reconstructed object is also included in the form of the logarithmic probability function of the attenuation values.

Abstract: A method and a computed tomography unit are disclosed, that render it possible in a simple way to remove ring artifacts from tomograms Ik, particularly in the case of a fast feed of the recording region per revolution of the recording system of the computed tomography unit by calculating a ring artifact image Ik for each tomogram Ik. In this procedure, temporary ring artifact images Rtk are firstly calculated for each tomogram Ik, and subsequently the final ring artifact image Rk is formed for the purpose of correcting the respective tomogram Ik by averaging over at least a portion Tsub of the temporary ring artifact images Rtk, the temporary ring artifact images Rtk being rotated before averaging in such a way that the ring artifacts present in the temporary artifact images Rtk substantially coincide and their position substantially corresponds to the ring artifacts present in the tomogram Ik.