Abstract: A filtering device includes an X-ray translucent substrate having a plurality of septa disposed therein at a plurality of fixed positions with respect to the substrate. A controller is programmed to acquire a first set of projection data at a first energy spectrum by controlling the X-ray source to emit the X-rays at the first energy spectrum and controlling the position of the filtering device to focally align the plurality of septa with the X-ray beam emitted from the focal spot, and to acquire a second set of projection data at a second energy spectrum with a mean energy greater than the mean energy of the first energy spectrum by controlling the X-ray source to emit the X-rays at the second energy spectrum and controlling a change in the position of the filtering device to focally misalign the plurality of septa with the X-ray beam emitted from the focal spot.

Abstract: A multi-energy X-ray imaging system includes an X-ray source and an X-ray detector. A filtering device includes an X-ray translucent substrate having a plurality of septa disposed therein at a plurality of fixed positions with respect to the substrate. A controller is programmed to acquire a first set of projection data at a first energy spectrum by controlling the X-ray source to emit the X-rays at the first energy spectrum and controlling the position of the filtering device to focally align the plurality of septa with the X-ray beam emitted from the focal spot, and to acquire a second set of projection data at a second energy spectrum with a mean energy greater than the mean energy of the first energy spectrum by controlling the X-ray source to emit the X-rays at the second energy spectrum and controlling a change in the position of the filtering device to focally misalign the plurality of septa with the X-ray beam emitted from the focal spot.

Abstract: The present invention discloses a computed tomography imager comprising: an x-ray source disposed in a gantry; a detector assembly for receiving an x-ray emission from an x-ray source, the x-ray source and the detector assembly rotatable about an imaging target; an imager control system for selectively modulating a kVp operating value in the x-ray source during a scan slice in accordance with an x-ray modulation software program; and a computer for receiving data from the detector assembly, and for providing control signals to the imager control system by executing the x-ray modulation software program for at least a portion of the total possible rotational scanning range of the x-ray source.

Abstract: In dual energy CT, through basis material decomposition (BMD), a pair of density images can be reconstructed. The noises in this image pair are negatively correlated due to the BMD process. A technique is presented for obtaining the monochromatic images at desired energy levels with reduced correlation noise. The technique includes obtaining a plurality of optimum attenuation coefficients for an energy level, selecting a desired energy level, obtaining a plurality of desired attenuation coefficients for the desired energy level, computing a scaling factor for a corresponding noise component based on the optimum attenuation coefficients and the desired attenuation coefficients, and generating a monochromatic image based upon the scaling factor.

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: The present invention discloses a computed tomography imager comprising: an x-ray source disposed in a gantry; a detector assembly for receiving an x-ray emission from an x-ray source, the x-ray source and the detector assembly rotatable about an imaging target; an imager control system for selectively modulating a kVp operating value in the x-ray source during a scan slice in accordance with an x-ray modulation software program; and a computer for receiving data from the detector assembly, and for providing control signals to the imager control system by executing the x-ray modulation software program for at least a portion of the total possible rotational scanning range of the x-ray source.

Abstract: A CT system includes a gantry, an x-ray source, a generator configured to energize the x-ray source to a first kVp and to a second kVp, a detector, and a controller. The controller is configured energize the x-ray source to the first kVp for a first time period, subsequently energize the x-ray source to the second kVp for a second time period, integrate data for a first integration period that includes a portion of a steady-state period of the x-ray source at the first kVp, integrate data for a second integration period that includes a portion of a steady-state period of the x-ray source at the second kVp, compare a signal-to-noise ratio (SNR) during the first integration period (SNRH) and the second integration period (SNRL), adjust an operating parameter of the CT system to optimize an SNRH with SNRL, and generate an image using the integrated data.

Abstract: A method for calibrating and reconstructing material density images in a dual-spectral computed tomography (CT) system 100 is disclosed. An X-ray source in the CT system 100 emits a first X-ray spectrum and a second X-ray spectrum towards an object. The method includes computing calibration coefficients by using projection data from the object for the two X-ray spectra and by linearizing at least two basis materials such as bone and water simultaneously. Further, basis materials decomposition coefficients for the at least two basis materials are computed by linearizing the basis materials individually. Correction values for the projection data and for the basis materials are then computed by using the basis materials decomposition coefficients and the calibration coefficients. The computed correction values are used in reconstructing material density images for the basis materials.

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: A CT detector capable of energy discrimination and direct conversion is disclosed. The detector includes multiple layers of semiconductor material with the layers having varying thicknesses. The detector is constructed to be segmented in the x-ray penetration direction so as to optimize count rate performance as well as avoid saturation. The detector also includes variable pixel pitch and a flexible binning of pixels to further enhance count rate performance.

Abstract: In dual energy CT, through basis material decomposition (BMD), a pair of density images can be reconstructed. The noises in this image pair are negatively correlated due to the BMD process. A technique is presented for obtaining the monochromatic images at desired energy levels with reduced correlation noise. The technique includes obtaining a plurality of optimum attenuation coefficients for an energy level, selecting a desired energy level, obtaining a plurality of desired attenuation coefficients for the desired energy level, computing a scaling factor for a corresponding noise component based on the optimum attenuation coefficients and the desired attenuation coefficients, and generating a monochromatic image based upon the scaling factor.

Abstract: A method for localizing optical emission is disclosed. The method involves identifying a first readout channel of a first pixellated photodetector array based on an impact of a first photon on the first pixellated photodetector array. The first photon is emitted by a scintillator unit of a scintillator array and the first readout channel corresponds to a column of one or more pixels of the first pixellated photodetector array. The method also involves identifying a second readout channel of a second pixellated photodetector array based on an impact of a second photon on the second pixellated photodetector array. The second photon is emitted by the scintillator unit and the second readout channel corresponds to a row of one or more pixels of the second pixellated photodetector array. The method further involves identifying the scintillator unit based on the first readout channel and the second readout channel.

Abstract: A method for calibrating and reconstructing material density images in a dual-spectral computed tomography (CT) system 100 is disclosed. An X-ray source in the CT system 100 emits a first X-ray spectrum and a second X-ray spectrum towards an object. The method includes computing calibration coefficients by using projection data from the object for the two X-ray spectra and by linearizing at least two basis materials such as bone and water simultaneously. Further, basis materials decomposition coefficients for the at least two basis materials are computed by linearizing the basis materials individually. Correction values for the projection data and for the basis materials are then computed by using the basis materials decomposition coefficients and the calibration coefficients. The computed correction values are used in reconstructing material density images for the basis materials.

Abstract: A system and method for ascertaining the identity of an object within an enclosed article. The system includes an acquisition subsystem utilizing a stationary radiation source and detector, a reconstruction subsystem, a computer-aided detection (CAD) subsystem, and a 2D/3D visualization subsystem. The detector may be an energy discriminating detector. The acquisition subsystem communicates view data to the reconstruction subsystem, which reconstructs it into image data and communicates it to the CAD subsystem. The CAD subsystem analyzes the image data to ascertain whether it contains any area of interest. Any such area of interest data is sent to the reconstruction subsystem for further reconstruction, using more rigorous algorithms and further analyzed by the CAD subsystem. Other information, such as risk variables or trace chemical detection information may be communicated to the CAD subsystem to be included in its analysis.

Abstract: A detector assembly is presented. The detector assembly includes a first detector layer having a top side and a bottom side, where the first detector layer includes a plurality of first coupling gaps. Additionally, the detector assembly includes a first interconnect structure operationally coupled to the first detector layer and configured to facilitate transfer of a first set of image data from the first detector layer to backplane electronics. The detector assembly also includes a second detector layer having a top side and a bottom side and disposed adjacent the bottom side of the first detector layer, where the second detector layer includes a plurality of second coupling gaps configured to facilitate passage of the first interconnect structure from the first detector layer to the backplane electronics.

Abstract: An adaptive data acquisition circuit (26) includes an amplifier (14) for amplifying electrical pulses generated by a detector (12) responsive to energy incident at the detector. The adaptive data acquisition circuit also includes a counting circuit (28) for counting amplified electrical pulses generated by the amplifier. In addition, the adaptive data acquisition circuit includes a digital logic circuit (30) for determining a pulse parameter indicative of a pulse rate and an amount of energy present in the amplified electrical pulses and for generating a control signal (34) responsive to the pulse parameter for controlling an operating parameter of the data acquisition circuit.

Abstract: A method for identifying localized optical emission is disclosed. The method involves identifying a region, which corresponds to a plurality of scintillator units of a scintillator, on a position sensitive photodetector that is impacted by one or more photons. The method further involves identifying a readout channel of a pixellated photodetector array that corresponds to a pixel associated with a scintillator unit impacted by the one or more photons. The method, further involves, identifying the scintillator unit based on the region and the readout channel.

Abstract: Various configurations for scatter reduction and control are provided for CT imaging. These configurations include an imaging system having a stationary detector extending generally around a portion of an imaging volume and a distributed X-ray source placed proximal to the stationary detector for radiating an X-ray beam toward the stationary detector. A scatter control system is further provided that is configured to adaptively operate in cooperation with the stationary detector and the distributed X-ray source to focally align collimator septa contained therein to the X-ray beam at a given focal point and to provide X-ray beam scatter control.

Abstract: A detector assembly is presented. The detector assembly includes a first detector layer having a top side and a bottom side, where the first detector layer includes a plurality of first coupling gaps. Additionally, the detector assembly includes a first interconnect structure operationally coupled to the first detector layer and configured to facilitate transfer of a first set of image data from the first detector layer to backplane electronics. The detector assembly also includes a second detector layer having a top side and a bottom side and disposed adjacent the bottom side of the first detector layer, where the second detector layer includes a plurality of second coupling gaps configured to facilitate passage of the first interconnect structure from the first detector layer to the backplane electronics.

Abstract: An adaptive data acquisition circuit (26) includes an amplifier (14) for amplifying electrical pulses generated by a detector (12) responsive to energy incident at the detector. The adaptive data acquisition circuit also includes a counting circuit (28) for counting amplified electrical pulses generated by the amplifier. In addition, the adaptive data acquisition circuit includes a digital logic circuit (30) for determining a pulse parameter indicative of a pulse rate and an amount of energy present in the amplified electrical pulses and for generating a control signal (34) responsive to the pulse parameter for controlling an operating parameter of the data acquisition circuit.