Abstract: The present invention is directed to multiple aperture devices (MADs) for beam shaping in x-ray imaging. Two or more of these binary filters can be placed in an x-ray beam in series to permit a large number of x-ray fluence profiles. However, the relationship between particular MAD designs and the achievable fluence patterns is complex. The present invention includes mathematical and physical models that are used within an optimization framework to find optimal MAD designs. Specifically, given a set of target fluence patterns, the present invention finds, for example, a dual MAD design that is a “best fit” in generating the desired fluence patterns. This process provides a solution for both the design of MAD filters as well as the control actuation that is required (relative motion between MADs) that needs to be specified as part of the operation of a MAD-based fluence field modulation system.

Abstract: The present invention is directed to multiple aperture devices (MADs) for beam shaping in x-ray imaging. Two or more of these binary filters can be placed in an x-ray beam in series to permit a large number of x-ray fluence profiles. However, the relationship between particular MAD designs and the achievable fluence patterns is complex. The present invention includes mathematical and physical models that are used within an optimization framework to find optimal MAD designs. Specifically, given a set of target fluence patterns, the present invention finds, for example, a dual MAD design that is a “best fit” in generating the desired fluence patterns. This process provides a solution for both the design of MAD filters as well as the control actuation that is required (relative motion between MADs) that needs to be specified as part of the operation of a MAD-based fluence field modulation system.

Abstract: An imaging system (100) includes a radiation source (708) that emits radiation that traverses an examination region (706), a radiation detector array (716) with a plurality of detectors (1104N) that detect the radiation that traverses the examination region, a dynamic bowtie filter (718) between the radiation source and the examination region, a first motor (7221) and a second motor (7222), and a controller (724). The dynamic bowtie filter includes a first half wedge (7181) and a second half wedge (7182). The first motor is in mechanical communication with the first half wedge and moves the first half wedge and the second motor is in mechanical communication with the second half wedge and moves the second half wedge. The controller independently controls the first and second motors to move the first and second half wedges.

Abstract: Apparatus and methods are described for use with an X-ray system including an X-ray anti-scatter grid that includes at least a first layer of elongate radiopaque septa arranged such that longitudinal axes of each the septa belonging to the first layer are disposed along a first direction, in parallel to each other. Spaces between the septa are filled with air, and a rigid frame supports the septa. Two or more slotted plates are coupled to the rigid frame, each of the slotted plates defining a plurality of slots, each of the septa passing through a respective pair of slots defined by a pair of the slotted plates disposed on opposite sides of the frame from each other, such that the orientation of each of the septa with respect to the frame is determined by the orientation of the corresponding pair of slots with respect to the frame.

Abstract: An imaging system (100) includes a radiation source (708) that emits radiation that traverses an examination region (706), a radiation detector array (716) with a plurality of detectors (1104N) that detect the radiation that traverses the examination region, a dynamic bowtie filter (718) between the radiation source and the examination region, a first motor (7221) and a second motor (7222), and a controller (724). The dynamic bowtie filter includes a first half wedge (7181) and a second half wedge (7182). The first motor is in mechanical communication with the first half wedge and moves the first half wedge and the second motor is in mechanical communication with the second half wedge and moves the second half wedge. The controller independently controls the first and second motors to move the first and second half wedges.

Abstract: Apparatus and methods are described for use with an X-ray system including an X-ray anti-scatter grid that includes at least a first layer of elongate radiopaque septa arranged such that longitudinal axes of each the septa belonging to the first layer are disposed along a first direction, in parallel to each other. Spaces between the septa are filled with air, and a rigid frame supports the septa. Two or more slotted plates are coupled to the rigid frame, each of the slotted plates defining a plurality of slots, each of the septa passing through a respective pair of slots defined by a pair of the slotted plates disposed on opposite sides of the frame from each other, such that the orientation of each of the septa with respect to the frame is determined by the orientation of the corresponding pair of slots with respect to the frame.

Abstract: A system includes memory (420) with instructions for at least one of processing spectral CT projection data to mitigate at least one of noise of the spectral CT projection data or a noise induced bias of the spectral CT projection data or generating a decomposition algorithm that mitigates the noise induced bias of the spectral CT projection data. The system further includes a processor (418) that executes the instructions and at least one of processes the spectral CT projection data or generates the decomposition algorithm and decomposes the spectral CT projection data to basis materials. The system further includes a reconstructor (434) that reconstructs the basis materials, thereby generating spectral images.

Abstract: The present invention is directed to multiple aperture devices (MADs) for beam shaping in x-ray imaging. Two or more of these binary filters can be placed in an x-ray beam in series to permit a large number of x-ray fluence profiles. However, the relationship between particular MAD designs and the achievable fluence patterns is complex. The present invention includes mathematical and physical models that are used within an optimization framework to find optimal MAD designs. Specifically, given a set of target fluence patterns, the present invention finds, for example, a dual MAD design that is a “best fit” in generating the desired fluence patterns. This process provides a solution for both the design of MAD filters as well as the control actuation that is required (relative motion between MADs) that needs to be specified as part of the operation of a MAD-based fluence field modulation system.

Abstract: An imaging system (500) includes a focal spot (510) that rotates along a path around an examination region (506) and emits radiation. A collimator (512) collimates the radiation, producing a radiation beam (516) that traverses a field of view (520) of the examination region and a subject or object therein. A detector array (522), located opposite the radiation source, across the examination region, detects radiation traversing the field of view and produces a signal indicative of the detected radiation. A beam shaper (524), located between the radiation source and the collimator, rotates in coordination with the focal spot and defines an intensity profile of the radiation beam. The beam shaper includes a plurality of elongate x-ray absorbing elements (606) arranged parallel to each other along a transverse direction with respect to a direction of the beam, separated from each other by a plurality of material free regions (604).

Abstract: A system includes memory (420) with instructions for at least one of processing spectral CT projection data to mitigate at least one of noise of the spectral CT projection data or a noise induced bias of the spectral CT projection data or generating a decomposition algorithm that mitigates the noise induced bias of the spectral CT projection data. The system further includes a processor (418) that executes the instructions and at least one of processes the spectral CT projection data or generates the decomposition algorithm and decomposes the spectral CT projection data to basis materials. The system further includes a reconstructor (434) that reconstructs the basis materials, thereby generating spectral images.

Abstract: An imaging system (500) includes a focal spot (510) that rotates along a path around an examination region (506) and emits radiation. A collimator (512) collimates the radiation, producing a radiation beam (516) that traverses a field of view (520) of the examination region and a subject or object therein. A detector array (522), located opposite the radiation source, across the examination region, detects radiation traversing the field of view and produces a signal indicative of the detected radiation. A beam shaper (524), located between the radiation source and the collimator, rotates in coordination with the focal spot and defines an intensity profile of the radiation beam. The beam shaper includes a plurality of elongate x-ray absorbing elements (606) arranged parallel to each other along a transverse direction with respect to a direction of the beam, separated from each other by a plurality of material free regions (604).

Abstract: An imaging system includes an x-ray source, a detector that receives x-rays emitted from the x-ray source, a DAS configured to count photon hits in the detector that occur at photon energies above at least a low keV threshold, a medium keV threshold, and a high keV threshold, and a computer operably coupled to the DAS. The computer is programmed to vary each of the medium keV threshold and the high keV threshold over a continuous keV range during data acquisition to define low, medium, and high keV bins that are based on the low, medium, and high keV thresholds, obtain photon counts in the low, medium, and high keV bins in a plurality of keV threshold combinations, calculate a noise variance as a function of at least one of the keV thresholds, and identify a noise minimum and low, medium, and high keV thresholds that correspond thereto.

Abstract: An imaging system includes an x-ray source, a detector that receives x-rays emitted from the x-ray source, a DAS configured to count photon hits in the detector that occur at photon energies above at least a low keV threshold, a medium keV threshold, and a high keV threshold, and a computer operably coupled to the DAS. The computer is programmed to vary each of the medium keV threshold and the high keV threshold over a continuous keV range during data acquisition to define low, medium, and high keV bins that are based on the low, medium, and high keV thresholds, obtain photon counts in the low, medium, and high keV bins in a plurality of keV threshold combinations, calculate a noise variance as a function of at least one of the keV thresholds, and identify a noise minimum and low, medium, and high keV thresholds that correspond thereto.

Abstract: The present invention provides a novel anti-scatter device for X-ray imaging with a position encoder-controlled grid motion. Te device comprising an X-ray radiation source, which produces a primary beam that is directed to an examined body; a high voltage generator in communication with said X-ray radiation source; an X-ray detector; a grid positioned within said primary beam between said examined body and said X-ray detector; an actuating means adapted to move said grid; a measuring means; adapted to measure the position of the grid during the X-ray exposure; and a controlling means for synchronizing the grid motion with the X-ray exposure.

Abstract: A method and apparatus for examining an object by rotating a radiant energy generator around the object while projecting a beam of radiant energy towards the object to impinge the object at a plurality of angles in each of a plurality of planes substantially perpendicular to the z-axis, and detecting radiant energy leaving the object after impinging same, to produce sets of projection measurements representing slices of the object in the planes. During rotation of the radiant energy generator, the radiant energy beam is sequentially modulated between two locations along the z-axis to produce, during each rotation of the generator, two sets of projection measurements representing two slices of the object, which projection measurements are used in an interlaced manner for reconstructing the image of the object.

Abstract: A method and apparatus for processing images received on an image sensor of rectangular configuration bounded by four outer edges and including a plurality of pixel elements arranged in a rectangular matrix includes the following operations: A. locating an initial rectangular-matrix region consisting of pixel elements determined to be free of an artifact; B. sequentially testing each pixel element along two contiguous outer edges of the image sensor, starting from the initial rectangular-matrix region, to determine whether the pixel value of the tested pixel element is sufficiently large to indicate the probability of an artifact, and for each such pixel element found to have such a pixel value, replacing its pixel value with another having a relation to the pixel value of its closest neighbours found to be free of an artifact, thereby cleaning the respective pixel element; and C. cleaning in a similar manner each of the remaining pixel elements.

Abstract: A system for reducing afterglow induced artifacts by filtering out afterglow using recursive filters that are tailored to match the intensity and decay time of the scintillating detectors that produce the afterglow.

Abstract: A CT scanner using a rotate-rotate mode wherein the detector is designed to simultaneously detect X-rays that have traversed multiple-planar sections in a patient being scanned.