Abstract: For visualizing a limited part of a 3D medical image-point-related data set, Selectively, a geometrically selected part of the data set is suppressed and an image rendered based on any non-suppressed part of the data set. The selected geometrically selected part includes a first selection containing all points associated to a nearer region with respect to a first clipping plane, and all points associated to a farther region with respect to a second clipping plane, respectively. The image rendered thereby is based on an intermediate region between the first clipping plane and the second clipping plane.

Abstract: A method is disclosed for generating images of a human or animal body on the basis of 3D-reconstructions from 3D-XRAY or 3D-Computer Tomography measurements, which bodies comprise both natural tissue and one or more high-density objects. The method comprises the steps of executing the measurements, distinguishing the one or more high-density objects and executing a separating procedure thereon for generating an improved image of regions of the natural tissue. In particular, the method comprises the following steps: applying a ramp filter on the various projection measurements to single out the one or more high-density objects; segmenting the singled-out one or more high-density objects into a separate 3D reconstruction; suppressing the reconstructed one or more high-density objects from the original projection measurements; and segmenting said projection measurements without the suppressed one or more high-density objects.

Abstract: A method and a device provide for the registration of two 3D image data sets of an object to be examined. The object to be examined is provided with a plurality of markers In order to enable a registration to be carried out, the positions of the markers in the 3D image data sets are first determined in a co-ordinate system associated with the relevant 3D image data set. The distances between the markers and/or the angles formed between lines which intersect in a marker and extend through two further markers are then determined. Finally, a transformation rule for the transformation of one of the 3D image data sets to the co-ordinate system of the other 3D image data set is determined.

Abstract: A method is disclosed for generating images of a human or animal body on the basis of 3D-reconstructions from 3D-XRAY or 3D-Computer Tomography measurements, which bodies comprise both natural tissue and one or more high-density objects. The method comprises the steps of executing the measurements, distinguishing the one or more high-density objects and executing a separating procedure thereon for generating an improved image of regions of the natural tissue. In particular, the method comprises the following steps: applying a ramp filter on the various projection measurements to single out the one or more high-density objects; segmenting the singled-out one or more high-density objects into a separate 3D reconstruction; suppressing the reconstructed one or more high-density objects from the original projection measurements; and segmenting said projection measurements without the suppressed one or more high-density objects.

Abstract: For imaging a 3D data set the method of the invention comprises the following steps in succession: acquisition of images, reconstructing a 3D data set, followed by visualization, the reconstruction being started with a limited initial range of orientations around the direction of a local midprojection from a starting point so as to be visualized, the acquisition being continued during visualization and the reconstruction being updated in accordance with the additional acquisition obtained up to a final result. In particular, the selected part comprises a first visualization covering a range of from about 40° to 60°, with a midprojection at about from 20° to 30°.

Abstract: A method and system of forming an X-ray layer image of an object being examined by an X-ray device having an X-ray source and an X-ray detector is described. At least one of the X-ray source and the X-ray detector can be displaced in an angular range around the object in order that X-ray projection images are acquired from different directions. When forming only a single X-ray layer image, or a plurality of X-ray layer images of parallel layers of the object, the time required for the acquisition of the X-ray projection images is notably reduced by forming the X-ray layer image directly from the X-ray projection images, where the resulting X-ray layer image is situated in a plane which extends essentially perpendicularly to the bisector of the angular range of displacement. The angular range of displacement can be less then 180°. The system and method is notably applicable to a C-arm X-ray device, in which the angular range can be chosen at will.

Abstract: An X-ray examination apparatus includes an X-ray source and an X-ray detector and is arranged to provide a series of projection images at respective orientations of the X-ray source (1) and the X-ray detector (2) relative to a predetermined frame of reference. The orientations of the projection images are calibrated relative to this frame of reference. A basic three-dimensional data set (23) is reconstructed from the projection images. A number of directions of observations (121-123) are calibrated relative to the same frame of reference. One or more additional X-ray images (111-113) are formed for the calibrated directions of observation, that is, preferably at successive instants in time. A dynamic series of three-dimensional data sets is formed by updating the basic three-dimensional data set by means of the additional X-ray images.

Abstract: For imaging a 3D data set the method of the invention comprises the following steps in succession: acquisition of images, reconstructing a 3D data set, followed by visualization, the reconstruction being started with a limited initial range of orientations around the direction of a local midprojection from a starting point so as to be visualized, said acquisition being continued during visualization and the reconstruction being updated in accordance with the additional acquisition obtained up to a final result. In particular, the selected part comprises a first visualization covering a range of from about 40° to 60°, with a midprojection at about from 20° to 30°.

Abstract: The invention relates to an anti-scatter grid for an X-ray device which serves to reduce scattered radiation generated in an object to be examined and includes a plurality of absorber laminations for the absorption of the scattered radiation and a channel medium which is transparent to X-rays and arranged between the absorber laminations. In order to enable notably simple and precise manufacture of such an anti-scatter grid while the primary radiation is attenuated as little as possible and scattered radiation is attenuated as much as possible, in accordance with the invention a non-elastic high-resistance foam, notably a polymethacrylimide high-resistance foam, is used as the channel medium. The invention also relates to a collimator, for example, for a single-photon emitter or a positron emitter, in which a non-elastic high-resistance foam is also used as the channel medium between the laminations.

Abstract: The invention relates to a method of reconstructing images from cone beam projection data from an examination zone (3) of an object to be examined. The cone beam projection data is acquired by means of an X-ray device which includes an X-ray source (1) and an X-ray image intensifier (2), the X-ray source (1) being guided along a trajectory around the examination zone (3) in order to acquire the projection data. First projection data are then acquired from the examination zone (3) in a first mode of operation of the X-ray image intensifier (2) which involves a low resolution. For a sub-zone (4) of the examination zone (3) second projection data is acquired in a second mode of operation of the X-ray image intensifier (2) which involves a high resolution. Subsequently, the first and second projection data is combined so as to form third projection data.

Abstract: An X-ray device for the formation of slice images of an object to be examined including an X-ray source, an X-ray detector, a transport device for moving the object during the acquisition of a series of X-ray projection images of the object in a movement plane situated parallel to the imaging plane, and a control device for controlling the acquisition of the X-ray projection images and the transport device. Slice images of the object are formed from the X-ray projection images by a tomosynthesis method.

Abstract: The invention relates to a method for the simultaneous display of at least two sectional images taken through a volume reconstructed from a 3D image data set.

Abstract: An X-ray examination apparatus includes an X-ray source and an X-ray detector and is arranged to provide a series of projection images at respective orientations of the X-ray source (1) and the X-ray detector (2) relative to a predetermined frame of reference. The orientations of the projection images are calibrated relative to this frame of reference. A basic three-dimensional data set (23) is reconstructed from the projection images. A number of directions of observations (121-123) are calibrated relative to the same frame of reference. One or more additional X-ray images (111-113) are formed for the calibrated directions of observation, that is, preferably at successive instants in time. A dynamic series of three-dimensional data sets is formed by updating the basic three-dimensional data set by means of the additional X-ray images.

Abstract: The invention relates to a method and a device for the registration of two 3D image data sets of an object to be examined which is provided with a plurality of markers which are contained in the 3D image data sets. Such a registration can be used, for example, in digital subtraction angiography.

Abstract: The invention relates to an anti-scatter grid for an X-ray device which serves to reduce scattered radiation generated in an object to be examined and includes a plurality of absorber laminations for the absorption of the scattered radiation and a channel medium which is transparent to X-rays and arranged between the absorber laminations. In order to enable notably simple and precise manufacture of such an anti-scatter grid while the primary radiation is attenuated as little as possible and scattered radiation is attenuated as much as possible, in accordance with the invention a non-elastic high-resistance foam, notably a polymethacrylimide high-resistance foam, is used as the channel medium. The invention also relates to a collimator, for example, for a single-photon emitter or a positron emitter, in which a non-elastic high-resistance foam is also used as the channel medium between the laminations.

Abstract: The invention relates to an X-ray device for the formation of slice images of an object (4) to be examined, which device includes an X-ray source (1), an X-ray detector (2), a transport device (3) for moving the object (4) to be examined during the acquisition of a series of X-ray projection images of the object (4) in a movement plane (B) that is situated parallel to the imaging plane (A), and also includes a control device (5) for controlling the acquisition of the X-ray projection images and the transport device (3), slice images of the object (4) to be examined being formed from the X-ray projection images by means of a tomosynthesis method.

Abstract: The invention relates to a method of reconstructing images from cone beam projection data from an examination zone (3) of an object to be examined. The cone beam projection data is acquired by means of an X-ray device which includes an X-ray source (1) and an X-ray image intensifier (2), the X-ray source (1) being guided along a trajectory around the examination zone (3) in order to acquire the projection data. First projection data are then acquired from the examination zone (3) in a first mode of operation of the X-ray image intensifier (2) which involves a low resolution. For a sub-zone (4) of the examination zone (3) second projection data is acquired in a second mode of operation of the X-ray image intensifier (2) which involves a high resolution. Subsequently, the first and second projection data is combined so as to form third projection data.

Abstract: The invention relates to a method of forming an X-ray layer image of an object (9) to be examined by means of an X-ray device which includes an X-ray source (2) and an X-ray detector (3); the X-ray source (2) and the X-ray detector (3) are displaced in an angular range (14) around the object (9) to be examined in order to acquire X-ray projection images from different directions. When only a single X-ray layer image is to be formed, or a plurality of X-ray layer images of parallel layers (S1, S2) of the object (9) to be examined, in accordance with the invention it is possible to reduce the expenditure required, notably the time required for the acquisition of the X-ray projection images, by forming the X-ray layer image directly from the X-ray projection images, the X-ray layer image being situated in a plane which extends essentially perpendicularly to the bisector (20) of the angular range (14), the angular range (14) amounting to less then 180°.

Abstract: For visualizing a limited part of a 3D medical image-point-related data set, selectively a geometrically selected part of the data set is suppressed and an image rendered as based on any non-suppressed part of the data set. In particular, the selected part comprises a first selection containing all points associated to a nearer region with respect to a first clipping plane and moreover all points associated to a farther region with respect to a second clipping plane, respectively. Thereby the rendered image is based on an intermediate region between the first clipping plane and the second clipping plane.

Abstract: A method of generating layer images from a number of single-shadow images and a device for performing this method. The absorption values associated with the image points of the single-shadow images are stored in a memory. The image value of the layer-image point is formed from the lowest absorption values associated with this layer-image point. Structures or artefacts which are situated outside the layer being imaged can thus be eliminated from the image.