Abstract: The invention relates to a system, a medical image acquisition system, and a method for imaging an interior of a turbid medium (25). The invention also relates to a marker (60) for use in the method for imaging an interior of a turbid medium (25). The system, the medical image acquisition system, and the method may be used for obtaining an image of an interior of a turbid medium (25) by: accommodation of a turbid medium (25) inside a receiving volume (20); irradiation of the receiving volume (20) with light from a light source; detection of light emanating from the receiving volume (20) as a result of irradiating the receiving volume (20) with light from the light source through the use of a photodetector unit. The detected light is then used to reconstruct an image of an interior of the turbid medium (25).

Abstract: A computed tomography system includes at least two x-ray sources (108), a at least one common detector (124), and a reconstruction system (136). The at least two x-ray sources (108) are aligned at different z-axis locations at about a same angular position and concurrently emit radiation that traverses an imaging region (116). The at least one detector (124) detects radiation emitted by the at least two x-ray source (108) and generates composite data indicative of the detected radiation. The reconstruction system (136) reconstructs the composite data to generate one or more images.

Abstract: According to the invention, there is provided a method of recording images of the heart in computer tomography, in which, in order to prevent movement artifacts, the images are reconstructed on the basis of similar movement states of the heart and different radiation intensities are used for different movement states. Also provided is a computer tomograph for recording images of the heart in computer tomography by means of time windows which exhibit similar movement states of the heart in order to prevent movement artifacts, said computer tomograph comprising a control device which controls a radiation source with different radiation intensities for different movement states.

Abstract: A computed tomography system includes an x-ray source (108) that rotates about and emits radiation through an imaging region (116). At least one finite energy resolution detector (112) detects the emitted radiation. The at least one finite resolution detector (112) includes a plurality of sub-detectors (204). Each of the plurality of sub-detectors (204) is associated with one or more different energy thresholds. Each of the energy thresholds is used to count a number of incident photons based on a corresponding energy level. A reconstruction system (136) reconstructs the photon counts to generate one or more images of a subject residing within the imaging region (116).

Abstract: A computer tomography apparatus (100) for examination of an object of interest (107), the computer tomography apparatus (100) comprising detecting elements (123) adapted to detect electromagnetic radiation coherently scattered from an object of interest (107) in an energy-resolving manner, and a determination unit (118) adapted to determine structural information concerning the object of interest (107) based on a statistical analysis of detecting signals received from the detecting elements (123).

Abstract: The reconstruction of the energy distribution at a detector with a detector element that consists of many small pixels, which count the number of photons above certain thresholds, is performed with a Maximum Likelihood analysis, according to an aspect of the present invention. Thus, the reconstruction scheme may use the redundancy in the measurement and may treat the Poisson statistics accordingly.

Abstract: A computer tomography apparatus (100) for examination of an object of interest (107) comprising an electromagnetic radiation source (104) adapted to emit electromagnetic radiation to an object of interest (107), a detecting device (108) adapted to detect electromagnetic radiation generated by the electromagnetic radiation source (104) and passed through the object of interest (107), and a motion generation device (101, 119) adapted to move the electromagnetic radiation source (104) and the detecting device (108) with respect to the object of interest (107) along a first trajectory and along a second trajectory which differs from the first trajectory, wherein the second trajectory is selected in such a manner that electromagnetic radiation detected during performing the second trajectory provides data which complete mathematically incomplete data detected during performing the first trajectory to thereby allow a reconstruction of structural information concerning the object of interest (107).

Abstract: The invention relates to a computer tomography method with a circular relative movement between the beam source and an iterative reconstruction method suitable therefor. The reconstruction method is substantially improved by deriving the first approximation image from a CT image, which is obtained from a prior acquisition during helical relative movement.

Abstract: The invention relates to a method and a device for the iterative reconstruction of cross-sectional images of the heart (7) of a patient based on projections (P1, . . . P5) from different directions which are for example generated with a helical cone-beam CT scanner. A cardiac weight function (f) quantifies how near the projections (P1, . . . ) are to a given observation phase (To) of the heart cycle based on simultaneously recorded electrocardiographic signals (ECG). The whole set of projections (P1, . . . ) is divided into subsets (S1, . . . ) which each contain only projections corresponding to a similar cardiac weight (f), and an iterative reconstruction algorithm like ART uses in one update or iteration step all projections of such a subset (S1, . . . ) simultaneously.

Abstract: A radiographic imaging apparatus includes a radiation detector (16) and a radiation source (12) which projects a non-parallel beam of radiation into field of view (14). A footprint of each voxel (v) which is projected on the detector (16) is corrected based on the position of the voxel (v) in the field of view (14) in relation to the radiation detector (16) and the radiation source (12). The contributions from substantially parallel redundant projections are further combined based on a fractional distance frac from a center point (82) of the voxel (v) to a center of each of the adjacent redundant projections.

Abstract: The invention relates to an imaging method, especially a computerized tomography method, with which an object is penetrated by rays from different directions and measured values, which depend upon the intensity of the rays after penetrating the object, are acquired by a detector unit. From these measured values, an object image is reconstructed by means of back projection of measured-value-dependent back projection values. Therein, the object image is divided into overlapping, quasi-spherically symmetric image segments, each being defined by an image value and a quasi-spherically symmetric base function.

Abstract: A computed tomography method and apparatus are provided wherein a radiation source moves circularly relative to an examination zone about an axis of rotation (14). The radiation source produces a cone beam of x-rays and the focal point of this cone beam is switched between at least two positions (23a, 23b) spaced apart from each other and arranged on a line parallel to the axis of rotation to enlarge the reconstructable examination zone parallel to the axis of rotation. Preferably, the image of the examination zone is reconstructed using an iterative reconstruction method, in particular an algebraic reconstruction method or a maximum likelihood method.

Abstract: It is described a method for reducing noise of X-ray attenuation data related to a first and second spectral X-ray data acquisition. The method comprises the steps of (a) acquiring data representing the X-ray attenuation behavior of a region of interest, (b) determining a first and a second attenuation-base line integral for the first and the second X-ray acquisition, respectively, and (c) calculating expected first and second signal to noise ratios for the first and the second attenuation-base line integral based on given signal to noise ratios for the first and second spectral X-ray data acquisition, respectively. The method further comprises the steps of (d) repeating the above mentioned steps of determining the attenuation-base line integrals and calculating the expected signal to noise ratios for a further first spectral X-ray data acquisition and (e) selecting improved spectral X-ray data acquisitions in order to enhance the overall signal to noise ratio of a final X-ray image.

Abstract: A tomographic apparatus (10) includes at least two x-ray sources (14) that rotate about and alternately emit radiation into an imaging region (22). The at least two x-ray sources (14) emit radiation from a first set of angular positions during a first data acquisition cycle and from a different set of angular positions during a subsequent data acquisition cycle. At least two sets of detectors (24) detect primary radiation emitted by a corresponding one of the at least two x-ray sources (14) and produce data representative of the detected radiation. An interleaver (32) interleaves the data associated with the first and the subsequent data acquisition cycles for each of the at least two x-ray sources (14).

Abstract: The reconstruction of images of an object of interest may introduce artifacts along lines of high gradients of absorption values. According to an exemplary embodiment of the present invention, these artifacts may efficiently be removed by a statistical weighing during reconstruction of the image. Advantageously, according to an aspect of the present invention, the reconstruction of the image may be performed iteratively, wherein the updates are weighted with the intrinsic statistical error of the measured photon counts. This may lead to an efficient removal of artifacts.

Abstract: A computed tomography scanner includes a first (20) and a second (21) detector. The second detector (21) has a relatively higher spatial resolution and a relatively smaller field of view (204) than that of the first detector (20). Projection data generated by the detectors (20, 21) is combined and reconstructed so as to generate relatively high resolution volumetric data (318) indicative of a region of interest (314) in an object under examination.

Abstract: Iterative methods for reconstructing of three-dimensional images based on projection data signals obtained by a computer tomography system often result in wrong absorption coefficients in particular for regions including a hollow space of an object under examination. Furthermore iterative methods show a slow convergence for calculating such absorption coefficients. According to embodiments of the present invention there is provided a method for an advanced reconstruction of three-dimensional images based on modified projection data signals. The modification includes an addition of a constant absorption value to the measured projection data. Advantageously the constant absorption value is an absorption line integral through a virtual body having the spatial constant absorption coefficient of water. The virtual body preferably has a volume which is slightly bigger than the object of interest.

Abstract: The invention relates to an imaging method, especially a computerized tomography method, with which an object is penetrated by rays from different directions and measured values, which depend upon the intensity of the rays after penetrating the object, are acquired by a detector unit. From these measured values, an object image is reconstructed by means of back projection of measured-value-dependent back projection values. Therein, the object image is divided into overlapping, quasi-spherically symmetric image segments, each being defined by an image value and a quasi-spherically symmetric base function.

Abstract: The increasing cone angle of current high-end and future CT systems leads to a decrease in image quality if approximate cone-beam reconstruction methods are used. According to an exemplary embodiment of the present invention, an iterative four-dimensional cardiac CT reconstruction is provided, in which phase volumes are selected from the four-dimensional data set, each having the same spatial volume at different phase points. Corresponding voxels inside these phase volumes are then forward projected onto the same projection. After calculation of a different projection, these voxels are updated. This may provide for an efficient implementation of an iterative four-dimensional cardiac cone-beam CT reconstruction.

Abstract: Iterative methods for reconstructing an image sequence of a moving object based on projection data usually require a high computationally effort. According to embodiments of the present invention there is provided such a method wherein a first image representing the object at a first phase is used as an initial image for iteratively reconstructing a second image at a second phase. A first gating function is assigned to the first phase, a second gating function is assigned to the second phase. When executing a first iteration for reconstructing the second image only projection data corresponding to a non-overlapping part of the two gating functions are used. For executing further iterations the amount of projection data corresponding to the overlapping part of the two gating functions may be gradually increased. Therefore, for all further but the last iteration the computationally effort is significantly reduced.