Abstract: For improved sampling, an x-ray detector system for a computed tomography scanner is provided. In an embodiment, the x-ray detector system includes at least one detector row which includes a plurality of detector modules each having a plurality of detector elements. Along the at least one detector row, a first portion of the detector elements is arranged in a grid at a first grid spacing in relation to its respective neighboring detector elements, and a second portion of the detector elements is arranged in a grid at a second grid spacing in relation to its respective neighboring detector elements.

Abstract: A method is disclosed for generating at least one x-ray image of a patient having incorporated contrast medium, using x-rays having an energy spectrum and an x-ray detector. The energy spectrum is modified by at least one first filter arranged in the beam path in front of the patient, the patient absorbing a dose in order to generate detector data for the x-ray image and the x-ray image having a CNR value which represents the ratio of the maximum contrast in the image to the noise. The energy spectrum and contrast medium are matched to each other, taking into account the thickness of the patient to be x-rayed, in such a way that an optimization criterion which is taken from an x-ray image that is generated or simulated by way of trials is maximized. Furthermore, an x-ray system is also disclosed.

Abstract: In a method for operating an imaging apparatus, and an imaging apparatus that has an x-ray source with a focus and a measurement volume with a central axis around which measurement volume the focus can be moved, acquisition of x-ray projections of a measurement subject that is arranged eccentrically relative to the central axis in the measurement volume are produced. The segment of the measurement volume in which the measurement subject is arranged is established based on an overview image and the projection angle range ?? in which x-ray projections should only be acquired in order to be able to reconstruct at least one image of the measurement subject is determined based on the establishment of the segment of the measurement volume.

Abstract: A method and a computed tomography scanner are disclosed for carrying out an angiographic examination of a patient, wherein the utilized computed tomography scanner includes at least one recording system mounted on a gantry such that it can rotate about a z-axis. Projection data is acquired from at least one prescribed angular position of the gantry for at least two different energies of X-ray radiation. The projection data is subsequently combined to form a resulting projection image by evaluating the projection data corresponding to the respective angular position, in which projection image at least one substance, which should be displayed selectively, is imaged with a high image contrast compared to the respective individual projection data. This procedure extends the field of application of the computed tomography scanner to projection-based angiography examinations, which were previously restricted to C-arm systems.

Abstract: A method for imaging with a radiotherapy device is provided. The radiotherapy device includes a movably mounted imaging apparatus with an X-ray source and an oppositely disposed X-ray detector. The method includes preparing a first image with the imaging apparatus from a first imaging direction. The imaging apparatus is moved to a position that permits the preparation of a second image from a second imaging direction extending at an angle to the first imaging direction. The method also includes preparing the second image with the imaging apparatus from the second imaging direction, and verifying the position of an object to be irradiated using the first image and the second image.

Abstract: A method and a device for determining the wear of an X-ray anode having an anode plate are provided. The method includes determining a reference value for a parameter that characterizes a property influenced by the dependence of an angle between radiation generated by the X-ray anode and the anode plate. The method also includes determining a value for the parameter after a specific operating time. The wear is established by comparing the determined value for the parameter with the reference value and correlating a deviation of the determined value for the parameter from the reference value with a wear state of the X-ray anode.

Abstract: A method is disclosed for imaging within the scope of a radiation therapy. In at least one embodiment, the method includes preparing one or more contrast agent-enhanced x-ray image data records; and using the contrast agent-enhanced x-ray image data record during an irradiation planning and/or during an irradiation session.

Abstract: A device to control an electron beam for the generation of x-ray radiation, has an electron emitter to generate an electron beam, to which emitter an emitter voltage can be applied, a diaphragm, at least two control elements associated with the diaphragm to affect the electron beam, and switching arrangement with which at least two different electrical voltages can be applied to the at least two control elements. The same electrical voltage is applied to each of the at least two control elements. Upon switching the voltage, an electrical circuit that delays the setting of the respective voltage at the one control element is associated with the connection line of the one control element with the switching arrangement to switch over the voltage. The invention moreover concerns an operating method for the device and an x-ray tube provided with the device.

Abstract: A method and a computational unit are disclosed for measuring the flow rate of a contrast agent in a vessel of a patient by way of a computed tomography examination. The patient is scanned by x-rays emitted in a fan-shape from two planes and the absorption from a multiplicity of rotational angles is determined while the contrast agent propagates through the at least one vessel. According to at least one embodiment of the invention, a three-dimensional data record of local absorption data with the vessel which can be filled by a contrast agent is reconstructed; a set of x-rays which pass through this vessel is determined for a multiplicity of temporally subsequent rotational angles of the x-rays. By determining the changing absorption values along this vessel from the temporally subsequent vessel/ray-sets, the propagation velocity of the contrast agent in this vessel can be determined from the spatial and temporal change in the absorption values in this vessel.

Abstract: In a method for operating an imaging apparatus, and an imaging apparatus that has an x-ray source with a focus and a measurement volume with a central axis around which measurement volume the focus can be moved, acquisition of x-ray projections of a measurement subject that is arranged eccentrically relative to the central axis in the measurement volume are produced. The segment of the measurement volume in which the measurement subject is arranged is established based on an overview image and the projection angle range ?? in which x-ray projections should only be acquired in order to be able to reconstruct at least one image of the measurement subject is determined based on the establishment of the segment of the measurement volume.

Abstract: A method and an X-ray device are disclosed for creating an X-ray projection image of a three-dimensional object under examination and for displaying the projection image. In at least one embodiment, pixel images are recorded from two different perspectives and a projection image is created by overlaying the two pixel images, wherein perspective-related offset of the mapping image pixels is taken into account, pixel-by-pixel, in relation to an imaging surface in the object under examination.

Abstract: A method and a computed tomography scanner are disclosed for carrying out an angiographic examination of a patient, wherein the utilized computed tomography scanner includes at least one recording system mounted on a gantry such that it can rotate about a z-axis. Projection data is acquired from at least one prescribed angular position of the gantry for at least two different energies of X-ray radiation. The projection data is subsequently combined to form a resulting projection image by evaluating the projection data corresponding to the respective angular position, in which projection image at least one substance, which should be displayed selectively, is imaged with a high image contrast compared to the respective individual projection data. This procedure extends the field of application of the computed tomography scanner to projection-based angiography examinations, which were previously restricted to C-arm systems.

Abstract: A method is disclosed for reconstructing CT image data. In at least one embodiment, the method includes providing measured CT projection data p based on the CT projection data p, reconstructing first CT image data fk=1, and on the basis of the first image data fk=1 iteratively generating k+1-th CT-image data according to the formula: fk+1=fk??(Q(Pfk?p)+?R(fk)) until the standard ?fk+1?fk?2 is ?n, with the reconstruction operator Q containing a noise weighting according to Q=B·Wstatist.·H. Aside from suppressing “cone” artifacts, the proposed method of at least one embodiment indicates a significant reduction in the image noise even after a few iterations.

Abstract: A method is disclosed for reconstructing CT image data. In at least one embodiment, the method includes provisioning CT projection data p. Secondly, it includes reconstruction of first image data fk=1 based on the CT projection data p. Thirdly, it includes iterative determination of k+1-th CT image data fk+1 on the basis of the first CT image data fk=1 as a function of: k-th CT image data fk, a reconstruction of differential projection data, the differential projection data being produced as the difference between reprojected CT image data fk and the CT projection data p, as well as a local contrast-dependent smoothing of the CT image data fk using a non-quadratic correction operator R(fk). Besides suppressing “cone” artifacts, the proposed method of at least one embodiment exhibits a significant reduction in image noise after just a few iterations.

Abstract: In at least one embodiment, two image data records of two computed tomography pictures of the object are provided that have been recorded in the context of a different spectral distribution of the X-radiation. For voxels of at least one interesting slice, there is calculated from the two image data records a ratio r that is yielded from measured or averaged X-ray attenuation values of the respective voxel or its environment in the context of the different spectral distributions of the X-radiation and prescribed X-ray attenuation values of soft tissue in the context of the different spectral distributions of the X-radiation according to a prescribed calculation rule. Upon overshooting of a threshold value for the ratio r the respective voxel is assigned either contrast agent or calcium-containing material as a function of the magnitude of r.

Abstract: A method and a device are disclosed for segmenting at least one substance in an x-ray image. In at least one embodiment of the method, two attenuation values relating to different energies of an x-radiation are acquired in relation to each pixel. The pixels are mapped into a two-dimensional feature space on the basis of the acquired attenuation values, and there is subsequently determined as assessment variable from the mapping of an image environment respectively assigned to the pixels the number of those pixels that fall in a classification region assigned to the substance. It is then possible to calculate in a simple way on the basis of the assessment variable a segmented image that contains the substance and in which misclassification can largely be avoided by taking account of the neighborhood relationship of the pixels.

Abstract: A device to control an electron beam for the generation of x-ray radiation, has an electron emitter to generate an electron beam, to which emitter an emitter voltage can be applied, a diaphragm, at least two control elements associated with the diaphragm to affect the electron beam, and switching arrangement with which at least two different electrical voltages can be applied to the at least two control elements. The same electrical voltage is applied to each of the at least two control elements. Upon switching the voltage, an electrical circuit that delays the setting of the respective voltage at the one control element is associated with the connection line of the one control element with the switching arrangement to switch over the voltage. The invention moreover concerns an operating method for the device and an x-ray tube provided with the device.

Abstract: A method is for determining a parameter in an image area as a measure of a homogeneity of a substance in an object, and to a method for segmenting a substance in an image that uses the parameter as an additional segmentation criterion. In the method, at least two X-ray images are acquired in relation to different energies E1, E2 of an X-radiation, and the parameter is determined from the statistical distribution of attenuation values Di(E1),Di(E2) where i=1, . . . , N in the image area such that faulty classifications can be avoided in a simple way during the segmentation.

Abstract: A filter method for tomographic 3D displays is disclosed, in which a volume model is used for display, which reproduces the volume of the examination object in the form of a large number of three-dimensional image voxels, and the image value of each voxel reproduces one object-specific characteristic of the examination object in this volume. According to the method, the original image voxels are processed using a 2D filter which is the same over the entire image area, and two different linear filters with selected directions which are obtained from the extremes of the previously calculated variances thus resulting in three data records with differently filtered image voxels, and in which, furthermore, the original image voxels and the filtered image voxels are mixed using local weights to form a result image.

Abstract: At least one embodiment of the present application relates to a method and/or an apparatus for determining the concentration of a substance in a body material that is composed of two different material components in an unknown ratio. In an embodiment of the method, two computed tomography pictures from which two image data records are reconstructed are recorded in conjunction with two different spectral distributions of the x-radiation. The x-ray attenuation values for each voxel of the two image data records are decomposed into three material components. The decomposition is performed on the assumption that the x-ray attenuation value xM of the body material without the substance is composed of the x-ray attenuation values xM1, xM2 of the first and second material component in accordance with the following equation: xM=f*xM1+(1-f)*XM2, f being a volume fraction of the first material component in the body material.