Abstract: A method for operating an x-ray image recording device having a movable x-ray detector on an-x-ray c-arm is provided. The x-ray C-arm supports an x-ray source and the x-ray detector which can be moved in the direction of the x-ray source. A variable is calculated which specifies the image quality of an x-ray image to be obtained in a position of the x-ray C-arm in a position of the x-ray detector and/or specifies the exposure dose of an operating person. A measure is taken as a function of the variable which results in a movement of the x-ray detector by the operating person and/or by an automatic movement. X-ray images are recorded in positions of the x-ray detector in which the image quality and/or the exposure dose of an operating person are optimal.

Abstract: A sequence of groups of projection images shows an object under examination comprising a vascular system and its environment. A computer determines a 2-dimensional evaluation image having a plurality of pixels based on combination images determined from the projection images of a group. The combination images have a plurality of pixels with pixel values. The sequence of the combination images shows the time characteristic of the distribution of a contrast medium in the object. The pixels of the evaluation image correspond to those of the projection images. The computer assigns each pixel, at least in a part area of the evaluation image, a type that is characteristic of whether the respective pixel corresponds to a vessel of the vascular system, a perfusion area or a background. It performs the assignment of the type on the basis of the time characteristic of the pixel values of the combination images.

Abstract: A radiation source for a radiation-based image acquisition device has an electron emitter to generate a focal spot for x-ray generation at a rotating anode. An arrangement is provided to generate an asymmetrical power input profile of the focal spot parallel to the movement direction of the rotating anode.

Abstract: To obtain a high-quality X-ray image from X-ray detectors with defective pixels, an X-ray image of an object is recorded by an active pixel matrix of an X-ray detector from at least two partial X-ray images, in which a first partial image is recorded from picture elements in a first position and at least one second partial image is recorded from picture elements in a second position of the pixel matrix, wherein the pixel matrix has at least one defective pixel at a defect site and the positions are selected such that the active pixel matrix is situated in the same plane in all positions, each displacement of the active pixel matrix from one into another position is an integer multiple of a pixel length, and at least one non-defective pixel is positioned in at least one other position at the respective defect sites of all positions.

Abstract: The invention relates to a method for operating an x-ray diagnostics device having an x-ray source, an x-ray image detector and an image system for generating a subtraction angiography sequence, in which a subtraction angiography sequence of low resolution individual images containing moving structures is created, registration of the individual images one with another is performed, and the images in the subtraction angiography sequence are used to compute a high resolution image.

Abstract: The invention relates to an X-ray device with an X-ray radiation source and with a preferably digital detector, which is placed in the beam path of the radiation source behind the object, particularly behind a patient. Scattered-rays are suppressed by means of a scanning device that scans the object and the detector only in sections. During a half-scanning process, the X-ray image is composed of half images, one image half being faded out.

Abstract: For scattered radiation correction in dual X-ray absorptiometry it is proposed to use the additional information supplied by the attenuation images in different energy ranges in a correction image area with homogeneous attenuation coefficients in order to determine the respective scattered radiation fraction. Toward that end, the inverse of the primary radiation function is considered and a search conducted for that scatter-to-primary ratio which leads to consistent mass per unit areas for the attenuation images recorded in different energy ranges.

Abstract: The invention relates to a method and a device for increasing contrast in medical images generated by an imaging system featuring an x-ray source and a detector. The detector detects x-rays of the x-ray source and converts image signals from the x-rays. The image signals are transferred to a control and processing unit for processing. Deconvolution of the image signals is carried out by application of an inverse modulation transfer function modified by a regularization. At least a volume image can be reconstructed from the deconvolved image signals.

Abstract: An x-ray diagnostics method is specified, in particular for use in angiography and cardiology, by means of which a particularly good image quality can be achieved in an easily manageable manner for the patient (P) and the medical personnel, at the same time as a comparatively low radiation exposure. Furthermore, a specific x-ray device (1) for implementing the method comprising an x-ray emitter (2), an x-ray detector (3) and a control unit (10) is specified to control the x-ray emitter (2). In this way the control unit (10) is allocated an operating element (15), by means of which a control parameter (S) characterizing the image quality, the detector input dose or the contrast noise ratio can be continuously varied, as a function of which a number of recording parameters (U,I,t,F) are set by means of the control device (10).

Abstract: The invention relates to a method for creating scatter-corrected mass density image in dual energy X-ray absorptiometry. The mass density image is created using additional information provided by attenuation images at different energy levels in an inhomogeneous correction image area. A multi-dimensional mass density is found that is consistent for a plurality of the attenuation images by inverting a primary radiation function. A scatter fraction is determined on the basis of the multi-dimensional mass density.

Abstract: A computer dismantles a two-dimensional initial image into partial images containing components that vary locally with partial image frequencies and a residual image containing a direct component which is locally invariable. For each partial image and residual image the computer determines a weighting factor and sums the weighted images into a final image. Based on a comparison of the partial image frequencies with a target frequency, the computer determines a partial image as a pilot image and its frequency as a pilot frequency. The computer determines weighting factors of the partial images so that partial images whose frequencies are below the pilot frequency are weighted less than the pilot image, and partial images whose frequencies are above the pilot frequency makes a large contribution when the noise component in the initial image is small and a small contribution when the noise component in the initial image is large.

Abstract: In a method for performing recordings for dual absorptiometry, a high-energy radiation pulse is performed before a low-energy radiation pulse. Furthermore the high-energy radiation pulse is arranged at the end of an assigned radiation window of the detector. This temporal sequence of a high-energy radiation pulse and a low-energy radiation pulse allows the total time for performing the recordings for dual absorptiometry to be minimized.

Abstract: The invention relates to a method and an x-ray examination unit for analyzing and representing x-ray projection images with an x-ray examination unit, where the function relation bU=ƒU?1(J˜/J0) is established between the attenuation value and a material-equivalent value as a function of the energy spectrum used, and for the purposes of projection representation, the magnitude of the material-equivalent value bU of a specific material is represented as an image value.

Abstract: The invention relates to an X-ray device with an X-ray radiation source and with a preferably digital detector, which is placed in the beam path of the radiation source behind the object, particularly behind a patient. Scattered-rays are suppressed by means of a scanning device that scans the object and the detector only in sections. During a half-scanning process, the X-ray image is composed of half images, one image half being faded out.

Abstract: Radiation image capture apparatus, in particular x-ray apparatus, comprising a radiation source and a radiation receptor, between which an examination object is to be positioned for image capture, a laterally closed apron-like radiation absorption apparatus which can be moved in the direction of the examination object to absorb scattered radiation emitted by the examination object being pro-vided at the radiation source and/or at the radiation receptor.

Abstract: With a method for controlling the dose or dose rate when recording x-ray images by means of a detector comprising image elements which record a plurality of dose data values, an actual value is determined for the dose or dose rate from the totality of the data values recorded by the image elements of a predetermined image segment, said actual value being compared with a predetermined target value in order to control the dose or dose rate when recording a further x-ray image. In accordance with the invention, the actual value is determined such that on the basis of a frequency distribution of the dose data values of the image elements assigned to the dominant, a p-quantile is determined, and that the dose data value assigned to the p-quantile is used to determine the actual value.

Abstract: The invention relates to a medical imaging system as well as a collision protection method for such a system. In this system the movement of a moveable part, e.g. a C-arm, is stopped or slowed down, if the part enters an individual protective zone enclosing the patient. This zone is calculated individually for each patient from the surface of the patient detected by an optical sensor.

Abstract: The invention relates to an x-ray diagnostics device having an x-ray tube for generating x-rays operated by a high voltage generator, having an x-ray detector for converting incident x-rays into electrical signals, having an image processing system and a control device for the duration of the x-ray pulse, in which parameters of the x-ray diagnostics device can be adjusted, with a computing unit being assigned to the control device, said computing unit determining the spatial frequency-dependent signal-to-noise ratio on the basis of the parameters and calculating therefrom the duration of the x-ray pulse and/or the remaining parameters required for a recording. The invention further relates to a method of this type for controlling the x-ray diagnostics device, in which the duration of the x-ray pulse is controlled such that the recognizability of relevant, moved objects is maximal.

Abstract: In recording projection images for dual absorptiometry, the optical thickness of an object being examined is determined on the basis of a projection image recorded in a high-energy range, and parameters for recording a projection image in the low-energy range are selected as a function of the determined optical thickness. The ratio between image quality and the radiation dosage of the object being examined can be optimized thereby.

Abstract: The invention relates to a method for “truncation correction” in an x-ray system, i.e. a correction method during the reconstruction of projection images of an object recorded from different projection angles, if parts of the object do not lie in the field of view of each projection image. The surface of the object is thereby optically detected and used during the reconstruction of projection images to supplement the missing image data.