Abstract: An imaging system includes an x-ray source that emits a beam of x-rays toward an object, a detector that receives high frequency electromagnetic energy attenuated by the object, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS. The computer is programmed to compute detector coefficients based on a static low kVp measurement and a static high kVp measurement, capture incident spectra at high and low kVp during fast kVp switching, compute effective X-ray incident spectra at high and low kVp during fast kVp switching using the captured incident spectra, scan a water phantom and normalize the computed detector coefficients to water, adjust the computed effective X-ray incident spectra based on the normalized detector coefficients, compute basis material decomposition functions using the adjusted X-ray incident spectra, and generate one or more basis material density images using the computed basis material decomposition functions.

Abstract: An imaging system includes an x-ray source that emits a beam of x-rays toward an object to be imaged, a detector that receives the x-rays attenuated by the object, a spectral notch filter positioned between the x-ray source and the object, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS and programmed to acquire a first image dataset at a first kVp, acquire a second image dataset at a second kVp that is greater than the first kVp, and generate an image of the object using the first image dataset and the second image dataset.

Abstract: The disclosure generally relates to dual-energy imaging, and in particular, techniques to produce and process dual-energy images using a dual-energy imaging system. One embodiment provides a method for generating at least one image of a region of interest in a patient, the method comprising: obtaining at least two radiological images of the region of interest identified with at least one marker arranged on and/or around the patient, wherein a first image is acquired. with a first X-ray energy and a second image is acquired with a second X-ray energy; and determining a final radiological image of the region of interest by linearly combining the two radiological images to obtain an image without the markers.

Abstract: A method includes performing an x-ray focal spot deflection to generate two complete projections from two different channels of an x-ray detector, wherein the channels are purposefully different from each other in some respect other than being different channels.

Abstract: A system and method provide local image enhancement. Internal native images of a patient may be acquired during an interventional procedure. A portion of the native images may show an interventional device or material. Subtracted images may be created by subtracting mask images from the native images, such as via either digital subtraction angiography to display vessel structures, or “roadmapping” during interventional procedures to deploy various medical devices and materials. The local level of absorption associated with the portion of the images showing a vessel structure or in which the interventional object resides may be determined from either the native images or the mask images. Subsequently, the subtracted images may be locally altered to compensate for the local level of absorption such that the visibility of a vessel structure or interventional object is enhanced. The subtracted images may be enhanced by altering the local contrast, brightness, or sharpness, or noise.

Abstract: Methods for energy-sensitive computed tomography systems that use checkerboard filtering. A method of enhancing image analysis of projection data acquired using a detector configured with a checkerboard filter includes disposing in a system a detector to receive a transmitted beam of X-rays traversing through an object, where the system is configured so the detector receives both high- and one of total- and low-energy projection data; receiving the high- and one of total- and low-energy projection data at the detector; and then estimating an effective atomic number of the object and/or processing the projection data so as to mitigate reconstruction artifacts. The present invention has been described in terms of specific embodiment(s), and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appended claims.

Abstract: A method and a computed tomography scanner are disclosed for carrying out an angiographic examination of a patient, wherein the utilized computed tomography scanner includes at least one recording system mounted on a gantry such that it can rotate about a z-axis. Projection data is acquired from at least one prescribed angular position of the gantry for at least two different energies of X-ray radiation. The projection data is subsequently combined to form a resulting projection image by evaluating the projection data corresponding to the respective angular position, in which projection image at least one substance, which should be displayed selectively, is imaged with a high image contrast compared to the respective individual projection data. This procedure extends the field of application of the computed tomography scanner to projection-based angiography examinations, which were previously restricted to C-arm systems.

Abstract: A CT system for scanning a patient is disclosed. In at least one embodiment, the system includes a tube/detector system, which can be set by a control device in respect of tube voltage and/or dose power; a patient couch, which can be displaced in a controlled fashion at least in the direction of a system axis; and a computer system, which can control the CT system. In at least one embodiment, the system includes an evaluation unit for a prescribed logical decision tree, which is integrated into the computer system, and which determines examination and scan parameters for the CT system on the basis of the input of at least one patient parameter described in a parameter list and operates the CT system using these examination and scan parameters.

Abstract: Systems, methods, and related computer program products for medical imaging and image-guided radiation treatment (IGRT) are described. In one embodiment, an IGRT system selectively integrates x-ray source arrays, dual-energy imaging, stereoscopic imaging, static and dynamic source collimation, and/or inverse geometry tomosynthesis imaging to acquire and/or track a target during radiation treatment. Advantages include reduced patient x-ray dose and/or reduced treatment delivery margins.

Abstract: Dual-energy absorptiometry is used to estimate intramuscular adipose tissue metrics and display results, preferably as related to normative data. The process involves deriving x-ray measurements for respective pixel positions related to a two-dimensional projection image of a body slice containing intramuscular adipose tissue as well as subcutaneous adipose tissue, at least some of the measurements being dual-energy x-ray measurements, processing the measurements to derive estimates of metrics related to the intramuscular adipose tissue in the slice, and using the resulting estimates. Processing the measurements includes an algorithm which places boundaries of regions, e.g., a large region and a smaller region. The regions are combined in an equation that is highly correlated with intramuscular adipose tissue measured by quantitative computed tomography in order to estimate intramuscular adipose tissue.

Abstract: A method and an image evaluation unit are disclosed for recognizing and marking contrast agents in blood vessels of the lung with the aid of a CT examination using at least two different x-ray energy spectra.

Abstract: An image processing apparatus includes a first spectrum estimating unit for reading the image information from a storage unit and estimating a spectrum of an object based on the read image information; a dye amount estimating unit for estimating dye amounts included in the object using the estimated spectrum; a second spectrum estimating unit for synthesizing a first spectrum using the estimated dye amounts; a spectrum subtractor for calculating a difference spectrum by subtracting the first spectrum from the spectrum; a dye amount correcting unit for correcting at least a part of the estimated dye amounts; a third spectrum estimating unit for synthesizing a second spectrum using the corrected dye amount; a spectrum adder for synthesizing a third spectrum by adding the second spectrum and the difference spectrum; and an image synthesizer for synthesizing a display image from the third spectrum.

Abstract: A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a ?-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a ?-ray image pickup signal is output).

Abstract: An imaging system includes an energy resolving detector (20) which generates data indicative of detected radiation having at least first and second energies. The system also includes an energy pre-processor (24), a motion calculator (26), and a reconstructor (22). In one embodiment, the apparatus uses a k-edge imaging technique to perform a motion compensated reconstruction of projection data indicative of an object under examination.

Abstract: A method of imaging an object includes providing a stationary x-ray tube, that is configured to emit a cone beam of x-rays, wherein a line extending from the x-ray tube and through the object defines a tomographic angle and a beamline, further wherein the x-ray tube is configured to emits x-rays from several tomographic angles; providing a system controller configured to operate the x-ray tube; locating at least one flat-panel area detector opposite the x-ray tube, thereby defining a field of view, wherein flat-panel area detector(s) is configured to receive the emitted x-rays from the different tomographic angles, further wherein the detector(s) comprise an array of L×W detector elements; conveying the object along the path of travel; and selectively emitting x-rays from the x-ray tube in the tomographic angles through the object, wherein each beamline emitted from the x-ray tube impinges on a different portion of the flat-panel area detector.

Abstract: Photon counting detectors may suffer from pulse sharing effects and fluorescence photon generation, which may lead to a degradation of the measured signals. According to an exemplary embodiment of the present invention, a detector unit is provided which is adapted for performing a coincidence detection and correction by comparing detection events of neighbouring cells, thereby providing for a coincidence identification followed by an individual coincidence correction. In order to reduce the number of coincidence detection and corresponding units per detector unit, a specific detector cell geometry may be applied.

Abstract: Disclosed are a method and a device for security-inspection of liquid articles with dual-energy CT imaging. The method comprises the steps of obtaining one or more CT images including physical attributes of liquid article to be inspected by CT scanning and a dual-energy reconstruction method; acquiring the physical attributes of each liquid article from the CT image; and determining whether the inspected liquid article is dangerous based on the physical attributes. The CT scanning can be implemented by a normal CT scanning technique, or a spiral CT scanning technique. In the normal CT scanning technique, the scan position can be preset, or set by the operator with a DR image, or set by automatic analysis of the DR image.

Abstract: An image processing system and method are provided to adaptively discriminate hard tissues and soft tissues of a target in a multi-energy X-ray system. The image processing system and method may minimize a decrease in a dynamic range (DR) for soft tissues affected by hard tissues in a target where the soft tissues and hard tissues are mixed.

Abstract: To prevent patients from being overexposed or underexposed, it has been attempted to modulate either voltage or current in conventional single energy CT systems. The voltage modulation causes incompatibility in projection data among the views while the current modulation reduces only noise. To solve these and other problems, dual energy CT is combined with voltage modulation techniques to improve the dosage efficiency. Furthermore, dual energy CT has been combined with both voltage modulation and current modulation to optimize the dosage efficiency in order to minimize radiation to a patient without sacrificing the reconstructed image quality.

Abstract: This invention is directed towards finding, locating, and confirming threat items and substances. The inspection system is designed to detect objects that are made from, but not limited to, special nuclear materials (“SNM”) and/or high atomic number materials. The system employs advanced image processing techniques to analyze images of an object under inspection (“OUI”), which includes, but is not limited to baggage, parcels, vehicles and cargo, and fluorescence detection.

Abstract: Two x-ray CT images are acquired of arterial plaque using x-rays at two different energy levels. The reconstructed images are normalized by adjusting pixel brightness until pixels depicting a region containing calcium have substantially the same brightness. The normalized images are subtracted to produce an image that depicts iron in the arterial plaque.

Abstract: A method is disclosed for producing a computed tomographic image of a subject, the method including: using a radiation source and detector, obtaining radiation transmission information relating to a region of interest in the subject; using the source and detector; obtaining a series of projection images of the region of interest. Each projection image is obtained by: directing an imaging beam of radiation from the source through the region of interest onto the detector along a respective direction; the detector having a detection area.

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 CT system includes a rotatable gantry having an opening for receiving an object to be scanned, an x-ray source coupled to the gantry and configured to project x-rays through the opening, a generator configured to energize the x-ray source to a first kVp and to a second kVp to generate the x-rays, and a detector having pixels therein, the detector attached to the gantry and positioned to receive the x-rays. The system includes a computer programmed to acquire a first view dataset and a second view dataset with the x-ray source energized to the first kVp, interpolate the first and second view datasets to generate interpolated pixels in an interpolated view dataset at the first kVp, using at least two pixels from each of the first and second view datasets to generate each interpolated pixel in the interpolated view dataset, and generate an image of the object using the interpolated view dataset.

Abstract: Certain embodiments provide a radiation analysis system for material segmentation utilizing computed tomography (CT) scans. The radiation analysis system includes an input module configured to input dual energy data. The dual energy scanned data includes first data corresponding to a first parameter and second data corresponding to a second parameter for a given scanned volume. The radiation analysis system also includes a processor configured to generate a scatter plot based on the dual energy data. The first data corresponds to a first axis and the second data corresponds to a second axis. The processor is configured to identify at least one material type based on the scatter plot.

Abstract: The disclosed CT scanner comprises at least one source of X-rays; a detector array comprising a plurality of detectors; and an X-ray filter mask arrangement disposed between the source of X-rays and detector array so as to modify the spectra of the X-rays transmitted from the source through the mask to at least some of the detectors so that the X-ray spectra detected by at least one set of detectors is different from the X-ray spectra detected by at least one other set of detectors.

Abstract: An X-ray CT system of an embodiment includes the following. An imaging region data acquisition part is configured to acquire a first imaging region and a second imaging region that have different widths from each other in the body axial direction based on a scanogram as imaging regions for performing scan imaging. An irradiation field control part is configured to obtain irradiation fields for the first and the second imaging regions, and control an irradiation field regulating part corresponding to the relative positions by a moving part so as to realize the irradiation fields obtained for each the imaging region. An X-ray control part is configured to control an X-ray generating part corresponding to the relative positions by the moving part so as to irradiate X-rays to the first and the second imaging regions for the scan imaging.

Abstract: Systems and methods include coordinated (KV) and megaelectronvolt (MV) computerized tomography (CT) imaging. KV and MV data are combined using a normalization process in order to generate CT images. The resulting CT images can include an improved signal to noise ratio in comparison to CT images generated using either KV or MV imaging alone. The coordinated KV and MV imaging process may be accomplished in significantly less time than using KV or MV imaging alone. This time savings has advantages in treatment verification. The MV projections are optionally generated using MV x-rays configured for x-ray treatment. In these cases the combined projections will reflect the treatment volume.

Abstract: An imaging system includes at least one radiation generating component (210) that alternately emits different radiation that traverse an examination region and a common detector (214) that detects radiation that traverses the examination region and generates a signal indicative thereof. Pulse generating circuitry (304) generates a pulse train, including a plurality of pulses, with a frequency indicative of the signal for the at least one radiation generating component (210) for a sampling interval. Processing electronics (220) determine an approximation of the signal for one of the at least one radiation generating components (210) for the sampling interval based on a number of pulses in the pulse train for the sampling interval and charge of the pulses in the pulse train.

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: An X-ray tube and a flat panel X-ray detector (FPD) are constructed movable parallel to each other in the same direction along a body axis which is a longitudinal direction of a patient. The X-ray tube intermittently emits radiation and the FPD detects radiation transmitted through the patient irradiated intermittently whenever the X-ray tube and FPD move every pitch. X-ray images O1, O2, . . . , OI, . . . , and OM are decomposed for every pitch noted above. The decomposed images are composed for each projection angle to obtain projection images P1, P2 and so on. Therefore, a sectional image with a long field of view in the longitudinal direction can be obtained by carrying out a reconstruction process based on the composed projection images.

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: An imaging system includes a radiation source (106, T1, T2, T3) that rotates about an examination region and emits radiation that traverses the examination region. The radiation source (106, T1, T2, T3) emits radiation having an energy spectrum that is selectively alternately switched between at least two different energy spectra during an imaging procedure. The system further includes an energy-resolving detector array (116, D1, D2, D3) that detects radiation traversing the examination region. The energy-resolving detector array (116, D1, D2, D3) resolves the detected radiation over at least two different energy ranges and produces energy-resolved output signals as a function of both emission energy spectrum and energy range. The system further includes a reconstructor (126) that performs a spectral reconstruction of the energy-resolved output signals. In another embodiment, the detector array (116) includes a photon-counting detector array (116).

Abstract: A method includes performing an x-ray focal spot deflection to generate two complete projections from two different channels of an x-ray detector, wherein the channels are purposefully different from each other in some respect other than being different channels.

Abstract: A detection system for wavelength-dispersive and energy-dispersive spectrometry comprises an X-ray detector formed from a solid-state avalanche photodiode with a thin entrance window electrode that permits the efficient detection of X-rays scattered from “light” elements. The detector can be tilted relative to the incident X-rays in order to increase the detection efficiency for X-rays scattered from “heavy” elements. The entrance window may be continuous conductive layer with a thickness in the range of 5 to 10 nanometers or may be a pattern of conductive lines with “windowless” areas between the lines. A signal processing circuit for the avalanche photodiode detector includes an ultra-low noise amplifier, a dual channel discriminator, a scaler and a digital counter. A linear array of avalanche photodiode detectors is used to increase the count rate of the detection system.

Abstract: A CT system includes a generator configured to energize an x-ray source to a first kilovoltage (kVp) and to a second kVp, and a computer that is programmed to acquire a first view dataset with the x-ray source energized to the first kVp and a second view dataset with the x-ray source energized to the second kVp, generate a base correction image using the first view dataset and the second view dataset, and reconstruct a pair of base material images from the first view dataset and from the second view dataset. The computer is also programmed to estimate artifact correlation in the pair of base material images using the base correction image, generate a pair of final base material images and a final monochromatic image, and correct one of the pair of final base material images and the final monochromatic image at a keV value using the estimated artifact correlation.

Abstract: The dual energy X-ray CT apparatus automatically optimizes a map for separation to achieve a high degree of separation accuracy and a reduction of dose. An X-ray attenuation coefficient acquired in the dual energy X-ray CT system is applied to a map for separation which represents a relationship between the X-ray attenuation coefficient and a composition of an object, thereby separating the composition of the object. The map formation unit for separation calculates an existing probability of each composition for each combination of multiple types of X-ray attenuation coefficients, and determines the composition having the largest existing probability as the composition corresponding to the combination of the X-ray attenuation coefficients, thereby forming the map for separation. This configuration allows a formation of the map for separation with respect to each imaging condition, and high degree of accuracy in separating composition can be achieved.

Abstract: A method and a device are disclosed for generating a CT image with a high time resolution using a computed tomography scanner which has at least two recording systems which are operated at different X-ray energy spectra. In at least one embodiment of the process, CT images are firstly reconstructed in each case from a semi-rotation with the two recording systems, with irradiated lengths of the contrast agent-enriched structures and the soft tissue being calculated therefrom. Subsequently, a common X-ray energy is assumed and artificial measurement data records are calculated therefor, using the knowledge of the irradiated lengths for both recording systems at the same common X-ray energy. The artificial measurement data of respectively a quarter-rotation per recording system is then used to calculate the final CT image with a high time resolution. The method affords the use of dual-energy scans without losing the high time resolution available in dual-source systems.

Abstract: 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.

Abstract: Methods, apparatuses and computer readable mediums for generating a volume visualization image based on multi-energy computed tomography data are provided. In one method, an image is rendered based on a multi-dimensional graphical representation of the computed tomography data. The computed tomography data includes at least two different energy image data sets and the multi-dimensional graphical representation represents intensity values of each of the at least two different energy image data sets.

Abstract: In at least one embodiment, two image data records of two computed tomography pictures of the object are provided that have been recorded in the context of a different spectral distribution of the X-radiation. For voxels of at least one interesting slice, there is calculated from the two image data records a ratio r that is yielded from measured or averaged X-ray attenuation values of the respective voxel or its environment in the context of the different spectral distributions of the X-radiation and prescribed X-ray attenuation values of soft tissue in the context of the different spectral distributions of the X-radiation according to a prescribed calculation rule. Upon overshooting of a threshold value for the ratio r the respective voxel is assigned either contrast agent or calcium-containing material as a function of the magnitude of r.

Abstract: A method and system for producing tomosynthetic images of a patient's breast. An x-ray source that delivers x-rays through a breast immobilized and compressed between a compression paddle and a breast platform and form an image at a digital x-ray receptor panel. Multiple x-ray images are taken as the x-ray source and the receptor move relative to the immobilized breast. In one preferred embodiment, the x-ray source travels from ?15° to +15°. The source can travel in an arc around the breast while the receptor travels linearly while remaining parallel and at the same distance from the breast platform. The sets of x-ray image data taken at different angles are combined to form tomosynthetic images that can be viewed in different formats, alone or as an adjunct to conventional mammograms.

Abstract: A computed tomography system includes a plurality of radiation sensitive detector elements (100) which generate a time varying signal indicative of x-ray photons received by the various detector elements (100). Photon counters (24) count the photons received by the various detector elements (24). Event-driven energy determiners (26) measure the total energy of the received photons. A mean, energy calculator (46) calculates a mean energy of the photons received by the various detector elements (100) during a plurality of reading periods.

Abstract: 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.

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 method and CT system are disclosed for preparing reconstructed CT image data records. In at least one embodiment of the method, an initial material distribution of an examination object is determined from CT data records determined from among at least two different spectral weightings with local energy-determined attenuation values, and local measurement-spectrum-dependent weighting functions are determined using this material distribution, enabling local measurement-spectrum-dependent attenuation functions to be calculated, and the distribution of local reference materials to be determined, with the help of plausibility considerations, from a list of reference materials over at least one specified region of interest in the examination object on the basis of previously calculated local measurement-spectrum-dependent attenuation functions.

Abstract: The present invention provides a material decomposition method capable of determining the distribution of density and constituent material concentration throughout an imaged object. The concentration, in the form of a mass fraction, mass percent, weight fraction, or weight percent, is determined from CT images acquired at different energy levels. The ratio of attenuation coefficients associated with one energy level to attenuation coefficients associated with another energy level is determined and used as an index in a lookup table to determine the concentration of a given material throughout the imaged object.

Abstract: An energy-sensitive computed tomography system is provided. The energy-sensitive computed tomography system includes an X-ray source configured to emit an X-ray beam resulting from electrons impinging upon a target material. The energy-sensitive computed tomography system also includes an object positioned within the X-ray beam. The energy-sensitive computed tomography system further includes a detector configured to receive a transmitted beam of the X-rays through the object. The energy-sensitive computed tomography system also includes a filter having an alternating pattern disposed between the X-ray source and the detector, the filter configured to facilitate measuring projection data that can be used to generate low-energy and high-energy spectral information.

Abstract: A method for calibrating a dual-energy CT system and an image reconstruction method are disclosed to calculate images of atomic number and density of a scanned object as well as its attenuation coefficient images at any energy level. The present invention removes the effect from a cupping artifact due to X-ray beam hardening. The method for calibrating a dual-energy CT system is provided comprising steps of selecting at least two different materials, detecting penetrative rays from dual-energy rays penetrating said at least two different materials under different combinations of thickness to acquire projection values, and creating a lookup table in a form of correspondence between said different combinations of thickness and said projection values.

Abstract: A radiographing apparatus according to an aspect of the present invention is characterized in that an image processing device comprises an acquisition device which acquires projection data of a first energy spectrum and projection data of a second energy spectrum, and a synthetic image generating device which synthesizes a first image on the basis of the projection data of the first energy spectrum, and a second image on the basis of the projection data of the second energy spectrum according to a predetermined synthetic condition, and generating a synthetic image, and a display device displays the generated synthetic image.