摘要:
A method includes decomposing, with a decomposer (118), agent-based time series projection data for an object or a subject into at least an agent based component. A projection data decomposer (118) includes a time series decomposer (204) that determines agent-based projection data based on agent-based time series projection data based on at least two energy dependent components. A computer readable storage medium containing instructions which, when executed by a computer, cause the computer to perform the act of: determining an agent-based component of agent-based time series projection data utilizing at least two components of the agent-based time series projection.
摘要:
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).
摘要:
The invention relates to a medical X-ray examination apparatus (1) for performing K-edge imaging. The medical X-ray examination apparatus (1) comprises an imaging unit (21), which is configured to spectrally decompose an X-ray absorption spectrum to image the X-ray absorption spectrum as a conventional X-ray absorption image (23a) and a K-edge absorption image (23b). The conventional X-ray absorption image (23a) includes data elements representing the anatomical background of an object of interest. The K-edge absorption image (23b) includes data elements representing quantitative information of local densities of material showing K-edge absorption within the object of interest. The imaging unit (21) comprises a spatial resolution reducer for reducing the spatial resolution of the K-edge absorption image, so that with a medical X-ray examination apparatus according to the invention an increased sensitivity of the selective imaging of a K-edge absorption image is achieved as compared to the sensitivity of the selective imaging of a K-edge absorption image of a known medical X-ray examination apparatus.
摘要:
The invention relates to a radiation detector (200), particularly an X-ray detector, which comprises at least one sensitive layer (212) for the conversion of incident photons (X) into electrical signals. A two-dimensional array of electrodes (213) is located on the front side of the sensitive layer (212), while its back side carries a counter-electrode (211). The size of the electrodes (213) may vary in radiation direction (y) for adapting the counting workload of the electrodes. Moreover, the position of the electrodes (213) with respect to the radiation direction (y) provides information about the energy of the detected photons (X).
摘要:
The invention relates to an imaging system for imaging an object (14) in an examination zone (5). The imaging system comprises a radiation source emanating radiation for illuminating the examination zone (5), a detection unit for generating detection values depending on the radiation after having passed the examination zone (5) and a moving unit for moving the 5 radiation source and the examination zone relative to each other along a first trajectory (15) and along a second trajectory (16). The position of at least one of the first trajectory (15) and of the second trajectory (16) with respect to the object is determined by a determination unit. The imaging system further comprises a reconstruction unit for reconstructing an image of the object (14) from the detection values using the determined position of the at least one of 10 the first trajectory (15) and the second trajectory (16).
摘要:
The invention relates to an imaging system for imaging a region of interest from energy-dependent projection data, wherein the imaging system comprises a projection data providing unit (1, 2, 3, 6, 7, 8) for providing energy-dependent first projection data of the region of interest. The imaging system comprises further an attenuation component image generation unit (12) for generating attenuation component images of the region of interest by generating energy-dependent second projection data using a model in which the projection data depend on attenuation component images. The component image generation unit (12) is adapted for generating the attenuation component images such that deviations of the second projection data from the first projection data are reduced.
摘要:
The invention relates to a CT imaging system for determining the flow of a substance within an object, wherein the CT imaging system comprises a polychromatic X-ray source and an energy-resolving X-ray detector for obtaining detection signals depending on the X-ray radiation after passing through the object. A calculation unit (12) determines a k-edge 5 component of the substance from the detection signals, and a reconstruction unit (13) reconstructs a time series of k-edge image from the determined k-edge component. A flow determination unit (14) determines flow values indicative for the flow within the object from the time series of k-edge images.
摘要:
Motion is one of the most critical sources of artifacts in helical conebeam CT. By comparing opposite rays corresponding to projection data, the amount of motion may be estimated and, in the following suppression of corresponding motion artifacts may be performed according to an exemplary embodiment of the present invention. The method of motion artifact compensation may be implemented in both approximate reconstruction algorithms and exact reconstruction algorithms. Advantageously, motion during the data acquisition is detected automatically and related motion artifacts may be suppressed adaptively.
摘要:
The invention relates to a computer tomography method in which a periodically moving object, in particular an organ of the body, is irradiated by a cone-shaped beam cluster (4) along a trajectory which runs on a cylindrical surface. The radiation transmitted through the object is measured by means of a detector unit (16), and at the same time the periodic movement of the object is recorded. In order to reconstruct the absorption distribution of the object, the measured values or the corresponding beams are rebinned to form a number of parallel projections, where for each of these projections a measured value is determined whose beam irradiates the object. The point in time at which this measured value was acquired is allocated to the respective projection. For the reconstruction, which may for example be carried out using a filtered back-projection, only projections whose allocated points in time lie within a predefined, specific time range (H1) within a period of the object movement are used.
摘要:
Spectral CT systems require cheap detectors with high energy resolution. According to an aspect of the present invention, a computer tomography apparatus comprises a detector element which is segmented into a plurality of sub-pixels. Each sub-pixel has at least two thresholds and counting channels, wherein the second threshold for each sub-pixel varies over the nominal detector element. This may provide for an improved energy-resolved photon counting.