Abstract: A line scan cone beam CT imaging system irradiates an object with an x-ray cone beam for multiple views. A projection data set of the object is acquired at each view. Between views, the cone beam and detector array are translated along parallel lines in opposite directions. An image is generated by converting the cone beam projection data set of the real object into a parallel-beam projection data set corresponding to a virtual object and using a total variation minimization image reconstruction algorithm to reconstruct a virtual image of the virtual object. The reconstruction algorithm includes the constraint that the Fourier transform of the reconstructed virtual image matches the known Fourier coefficients in the set of converted parallel-beam projections of the virtual object. The reconstructed virtual image is then transformed into an image of the real object.

Abstract: A method is for image reconstruction for computed tomography with a non-one-dimensional, extended detector. The rays of the detector are weighted during the backprojection as a function of their position in the beam.

Abstract: An X-ray CT apparatus is provided for reducing the amount of computation at image reconstruction thereby to shorten an image reconstruction time. The X-ray CT apparatus comprises a cradle which moves in a horizontal direction to convey a subject to a photography space, an X-ray detector comprising a plurality of detecting element rows, for obtaining projection data by a helical scan when the cradle is moved under acceleration/deceleration and at a constant velocity, and backprojection processing device for performing a backprojection process on the projection data. When image reconstruction is carried out using the projection data acquired when the cradle is moved under acceleration/deceleration, the backprojection processing device assumes a virtual image reconstruction plane P? where the cradle is assumed to be moved at the constant velocity, with respect to an image reconstruction plane P of each view and backprojects projection data onto the virtual image reconstruction plane P?.

Abstract: An X-ray CT apparatus includes an X-ray irradiation unit for applying X-rays based on a first X-ray tube voltage and X-rays based on a second X-ray tube voltage to a subject by being switched every one view, a projection data acquisition unit for acquiring projection data by which X-ray tube voltage information about the applied X-rays are identified, and an image reconstruction unit for identifying first energy projection data based on the first X-ray tube voltage, second energy projection data based on the second X-ray tube voltage, and transient energy projection data acquired upon switching between the first and second X-ray tube voltages based on the X-ray tube voltage information, the image reconstruction unit including a conversion processor that converts the transient energy projection data to another data using the transient energy projection data and performs image reconstruction using the data subsequent to the conversion process.

Abstract: For the purpose of improving efficiency in diagnosis by performing image reconstruction for slice planes lying at the same position in a subject both in a forward direction FD and backward direction BD, an amount of positional offset ‘dz’ is acquired, which amount represents a difference in a body axis direction ‘z’ along the forward direction FD and backward direction BD between a first subject position and a second subject position, the first subject position being a position to which a region to be imaged in the subject laid on a cradle 401 is moved when the cradle 401 is moved in the forward direction FD, and the second subject position being a position to which the region to be imaged in the subject laid on the moving cradle 401 is moved when the cradle 401 is moved in the backward direction BD such that the region to be imaged in the subject coincides with the first subject position.

Abstract: A method and a CT system are disclosed having a computation unit for distinguishing between four materials (M1, M2, M3, M4) in tomographic records of a dual-energy CT system, wherein the size of a two-dimensional or three-dimensional viewing area is defined around each voxel whose material content is to be distinguished. In an embodiment of the method, the adjacent voxels from the viewing area on an HU value diagram are imaged for each voxel (Vi) whose material content is to be distinguished, the distances from the diagonals are calculated for all the imaged voxels, and the mean squares of these distances are formed (x12, x22). If the mean square distance (x12, x22) to one diagonal is less than to the other diagonal, then the composition of the voxel is assumed to be composed of the materials to whose diagonal the lower mean square distance (x12, x22) occurs.

Abstract: A CT imaging system includes a computer that is programmed to rebin cone beam projection data into a series of two-dimensional sinograms based on an optimized ray consistency approach. The computer receives cone beam data from a detector array and is programmed to specify a plurality of view angles for the cone beam data. The computer selects a plurality of measured rays for each of the plurality of specified view angles, the plurality of measured rays having a view angle approximate to the specified view angle as determined by an optimized ray consistency. The computer also forms a two-dimensional sinogram for each of the plurality of specified view angles based on the selected plurality of measured rays. The computer then defines an image surface for each of the plurality of specified view angles based on the selected plurality of measured rays.

Abstract: A computed tomographic imaging system is provided for generating computed tomography images. The computed tomographic system includes a processor configured to access image data encoding X-ray projections at a detector position and a plurality of X-ray source beam focal spot positions and to align pixel values for the projections in a direction of deviation of the positions. The processor is also configured to determine a correction factor for at least one of the projections based upon the aligned pixel values and upon a sum of the projections and to correct the pixel values for the at least one of the projections based upon the correction factor.

Abstract: In the CT imaging of non-homogeneously moving objects such as the heart or the coronary vessel tree, there is a problem that different parts of the objects are at rest at different points in time. Thus, a gated reconstruction with a globally selected time point does not yield a sharp image of such objects. According to the present invention, a motion of the object is estimated, describing the motion of selected regions of these objects. Then, on the basis of the estimated motion, time points are determined, where these areas have minimal motion. Then, an image is reconstructed, wherein the data from which the respective regions are reconstructed, correspond to the respective time points, where the regions have minimal motion. Due to this, an improved image quality may be provided.

Abstract: The invention relates to a method for evaluating projection datasets of an object undergoing examination. Each projection dataset is assigned a swiveling angle and a recording instant. Each data element of each projection dataset defines a projection line along which an X-ray beam has traveled from an X-ray source to an X-ray detector. The projection datasets form recording groups each of which corresponds with the projection datasets that were recorded during a single swiveling action. A computer determines reconstruction datasets using the projection datasets. Each reconstruction dataset contains at least one reconstruction data value assigned to a reconstruction line. Using a temporal interpolation, the computer determines the reconstruction datasets in such a way that they refer to a uniform reconstruction time. The computer determines a reconstruction of the object undergoing examination using the reconstruction datasets.

Abstract: The present invention is directed to realize an X-ray CT apparatus for properly performing contrast imaging. An X-ray CT apparatus includes an imaging unit and a control unit for controlling the imaging unit.

Abstract: The present invention provides an X-ray tomography apparatus that positively extracts artifacts without decreasing directional resolution thereby to reduce the artifacts.

Abstract: The present invention provides an X-ray tomography apparatus that reduces artifacts.

Abstract: An X-ray computed tomography (CT) apparatus having an X-ray tube emitting an X-ray, a detector detecting X-rays transmitted through a subject to be examined, and a bed on which said subject to be examined is placed, said X-ray CT apparatus reconstructing the image of the subject to be examined from a transmission data obtained by emitting X-rays to the subject to be examined. The X-ray computed tomography (CT) apparatus further having an input part, a scan controlling part, a detecting part, a memory part, a segmentation part, a biological-signal synchronization reconstructing part, a biological-signal asynchronization reconstructing part, and a combining part.

Abstract: A radiographic imaging apparatus (10) comprises a primary radiation source (14) which projects a beam of radiation into an examination region (16). A detector (18) converts detected radiation passing through the examination region (16) into electrical detector signals representative of the detected radiation. The detector (18) has at least one temporally changing characteristic such as an offset B(t) or gain A(t). A grid pulse means (64) turns the primary radiation source (14) ON and OFF at a rate between 1000 and 5000 pulses per second, such that at least the offset B(t) is re-measured between 1000 and 5000 times per second and corrected a plurality of times during generation of the detector signals. The gain A(t) is measured by pulsing a second pulsed source (86, 100, 138) of a constant intensity (XRef) with a second pulse means (88). The gain A(t) is re-measured and corrected a plurality of times per second during generation of the detector signals.

Abstract: In a method for correction of scatter radiation errors in radiography and computer tomography, using flat panel detectors, initially an estimation of a scatter radiation distribution Scor(y,z) is undertaken, and a standard correction term ?pcor is subsequently calculated. Noise filtering of the standard correction term ?pcor with F(?pcor) is implemented and subsequently the noise-filtered standard correction term F(?pcor) is added to the logarithmized measured total projection data ps. The noise filtering can be implemented adaptively dependent on a previously-determined local noise variance. The method can be implemented in a radiography system and/or by a computer for generation and/or processing of projective and/or tomographic exposures, with a memory containing program codes causing the computer in operation to execute the steps of the method.

Abstract: An X-ray CT scanner includes X-ray tubes including a first X-ray tube and a second X-ray tube having fan angles different from each other, X-ray detectors including a first X-ray detector and a second X-ray detector which are respectively arranged to face the first X-ray tube and the second X-ray tube, collection data processing means for executing weighting processing to each of pieces of collection data including first collection data obtained by the first X-ray detector and second collection data obtained by the second X-ray detector to generate image data combined to be smooth in a direction corresponding to a channel direction of detection elements provided in the X-ray detectors, and image generating section for performing processing including image reconstruction processing with respect to pieces of collection data weighted by the collection data processing section to generate image data.

Abstract: The invention relates to a method for beam hardening correction in medical image. Beam hardening within the context of medical imaging projection image profiles are split up into a basic profile which is assigned to a homogeneous object area and into a detailed profile which is assigned to an inhomogeneous object area. On the basis of the basic profile and of the difference profile the mass occupancy of the different components in the object to be examined can be approximately determined. On the basis of the approximately determined mass occupancy the correction of the beam hardening can then be performed directly on the projection data.

Abstract: A tomographic apparatus includes a radiation source (12) having a plurality of focal spots (Fa, Fb, Fc, Fd) and a detector (20) which generates output signals indicative of radiation received along a plurality of rays. A height rebinner (34) performs a height rebinning of the acquired rays to generate height interpolated readings. A transverse rebinner (36) performs a two-dimensional transverse interpolation of the height interpolated rays in a canonical space to generate a plurality of transversely interpolated readings (302). The transversely interpolated readings (302) are reconstructed to generate a human readable image.

Abstract: The invention relates to a method for speeding up the scattered radiation correction in a computed tomography system with a radiation source and a detector constructed in large-area format with a number of rows of detectors, by which an object is scanned from numerous projection angles, uses the measured values for the attenuation of the radiation in generating projection data which is postprocessed for the purpose of reconstructing tomographic views, in doing which a beam hardening correction is applied directly to the projection data, whereby according to the invention the scattered radiation correction is also applied directly to the projection data.