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: 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: 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: A method for defining image quality characteristics of X-ray based medical projection imaging devices is provided. A spatial frequency-dependent signal-to-noise ratio function includes image quality parameters of spatial resolution, object contrast and noise. The detectability of an object embedded into a defined background, such as a cardiac guide wire in a patient is determined. An X-ray system may be defined and set up for obtaining an optimized image quality to determine the best object detectability for a given patient dose.

Abstract: A method and a suitable x-ray device (1) for carrying out the method are specified for effective and operationally simplified user-specific optimization of a parameter configuration (K) of an x-ray device (1), said configuration comprising at least one recording parameter (U,I,t,F). It is accordingly provided that a user (20) is shown a plurality of reference images (V,V1) for different reference parameter sets (PV) from a reference memory (21) in which are stored a large number of reference images (V,V0) each with an associated reference parameter set (PV), that for each reference image (V,V1) shown the user (20) submits an assessment (BM) of the image quality (V,V1), and that on the basis of the submitted assessments (BM) an optimized parameter configuration (K) is created from the reference parameter sets (PV) of the reference images (V,V1) shown.

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: 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: A device and a method for the multispectral correction of radiation hardening in computer tomography with variable tube voltage is described. In particular, a water correction and a post-reconstructive hardening correction is disclosed. To perform the water correction, project image data is corrected, in that correction values are obtained from a previously determined correction table, by means of which a correction of the projection image data can be performed. By means of an image reconstruction, this produces a corrected volumetric image.

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: A device and a method for the multispectral correction of radiation hardening in computer tomography with variable tube voltage is described. In particular, a water correction and a post-reconstructive hardening correction is disclosed. To perform the water correction, project image data is corrected, in that correction values are obtained from a previously determined correction table, by means of which a correction of the projection image data can be performed. By means of an image reconstruction, this produces a corrected volumetric image.

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 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.

Abstract: The invention relates to a method for presetting the imaging parameters during the generation of two-dimensional fluoroscopic x-ray images of a patient, wherein the optimally necessary dose for the fluoroscopic x-ray image is determined with the aid of a 3D representation, already present from prior examinations, of the internal structure of the patient and the intended imaging direction and this dose is used for the exposure of the fluoroscopic image.

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: 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: 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 at the radiation receptor.

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: A method for defining image quality characteristics of X-ray based medical projection imaging devices is provided. A spatial frequency-dependent signal-to-noise ratio function includes image quality parameters of spatial resolution, object contrast and noise. The detectability of an object embedded into a defined background, such as a cardiac guide wire in a patient is determined. An X-ray system may be defined and set up for obtaining an optimized image quality to determine the best object detectability for a given patient dose.

Abstract: A method and a suitable x-ray device (1) for carrying out the method are specified for effective and operationally simplified user-specific optimization of a parameter configuration (K) of an x-ray device (1), said configuration comprising at least one recording parameter (U,I,t,F). It is accordingly provided that a user (20) is shown a plurality of reference images (V, V1) for different reference parameter sets (PV) from a reference memory (21) in which are stored a large number of reference images (V, V0) each with an associated reference parameter set (PV), that for each reference image (V, V1) shown the user (20) submits an assessment (BM) of the image quality (V, V1), and that on the basis of the submitted assessments (BM) an optimized parameter configuration (K) is created from the reference parameter sets (PV) of the reference images (V, V1) shown.

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).