Abstract: A computed-tomography (CT) apparatus including a CT scanner including a rotating X-ray source, and a plurality of photon-counting detectors (PCDs) arranged in a fixed detector ring to capture incident X-ray photons emitted from the X-ray source. The plurality of PCDs includes a first plurality of first PCDs, each first PCD having a first collimator on a surface of the first PCD to block X-ray photons emitted from the X-ray source, the first collimator having openings of a first size, and a second plurality of second PCDs, each second PCD having a second collimator on a surface of the second PCD to block the X-ray photons emitted from the X-ray source, the second collimator having openings of a second size, the first size being different from the second size.

Abstract: An apparatus is provided that includes a digital processing circuit to obtain a digital signal corresponding to an output signal of a photon-counting detector; determine, from the obtained digital signal, a plurality of X-ray photons received by the photon-counting detector during a measurement period; determine a corresponding energy level of each of the plurality of X-ray photons; determine, based on the corresponding energy level, a corresponding weight for each of the plurality of X-ray photons; and calculate a sum of the corresponding weights of the plurality of X-ray photons.

Abstract: A method for performing reconstruction for a region of interest (ROI) of an object is provided. The method includes designating the ROI within the object, the ROI being located within a scan field of view (FOV) of a combined third- and fourth-generation CT scanner, the CT scanner including fixed photon-counting detectors (PCDs), and an X-ray source that rotates about the object in synchronization with a rotating detector. Further, the method includes determining, for each PCD, as a function of view angle, an on/off timing schedule, based on a size and location of the designated ROI, and performing a scan to obtain a first data set from the rotating detector and a second data set from the plurality of PCDs, while turning each PCD on and off according to the determined schedule. Finally, the method includes performing reconstruction using the first and second data sets to obtain ROI spectral images.

Abstract: An imaging method comprises: acquiring magnetic resonance data of a subject using a magnetic resonance component (30, 30?) disposed with the subject; acquiring nuclear imaging data of the subject with the magnetic resonance component disposed with the subject; determining a position of the magnetic resonance component respective to a frame of reference of the nuclear imaging data; and reconstructing the nuclear imaging data (60) to generate a nuclear image (62) of at least a portion of the subject. The reconstructing includes adjusting at least one of the nuclear imaging data and the nuclear image based on a density map (46) of the magnetic resonance component and the determined position of the magnetic resonance component respective to the frame of reference of the nuclear imaging data to correct the nuclear image for radiation absorption by the magnetic resonance component.

Abstract: A CT scanner apparatus includes an X-ray source mounted on a gantry of the CT scanner apparatus. The CT scanner apparatus also includes a first X-ray detector mounted on the gantry opposite to the X-ray source, and configured to detect X-rays emitted from the X-ray source and transmitted through an object. The CT scanner apparatus also includes a fixed, sparse array of second X-ray detectors. Each of the second X-ray detectors includes a plurality of stacked scintillators and a photosensor adjacent to a sidewall of the stacked scintillators in a side-readout configuration.

Abstract: In a diagnostic imaging system (10), a monitor (50) monitors periodic biological cycles of the subject (14). A trigger point detector (60) detects a time (t1, t2, . . . , tn) of a common, reoccurring reference point (R1, R2, . . . , Rn) in each periodic cycle of the subject (14). A sequence selector (62) selects a sequence (64) of nominal sampling segments (Si, S2, . . . , Sn). An adjustor (70) adjusts duration of each nominal sampling segment (Si, S2, . . . , Sn) to coincide with the times of detected reference points (R1, R2, . . . , Rn). A scaling processor (72) scales each adjusted segment based on a difference in duration between the corresponding nominal (Si, S2, . . . , Sn) and adjusted sampling segments (S?i, S?2, . . . , S?n).

Abstract: A photon-counting detector apparatus is configured to receive X-rays transmitted from an X-ray source. The photon-counting detector apparatus includes a first photon-counting detector having a first detecting material configured to detect photons using a first set of energy bins. The photon-counting detector apparatus also includes a second photon-counting detector arranged above the first photon-counting detector relative to an incidence direction of the X-rays transmitted from the X-ray source. The second photon-counting detector has a second detecting material configured to detect photons using a second set of energy bins. The first set of energy bins differs from the second set of energy bins.

Abstract: A CT scanner apparatus includes an X-ray source mounted on a gantry of the CT scanner apparatus. The CT scanner apparatus also includes a first X-ray detector mounted on the gantry opposite to the X-ray source, and configured to detect X-rays emitted from the X-ray source and transmitted through an object. The CT scanner apparatus also includes a fixed, sparse array of second X-ray detectors. Each of the second X-ray detectors includes a plurality of stacked scintillators and a photosensor adjacent to a sidewall of the stacked scintillators in a side-readout configuration.

Abstract: A computed-tomography apparatus that includes a CT scanner including an X-ray source and a detector covering respective angle ranges in the axial and transaxial planes of the CT scanner. The CT detector includes first detector elements disposed on a first surface to capture incident X-ray photons emitted from the X-ray source, and second detector elements sparsely disposed on a second surface different from the first surface, the second surface being farther away from the scanner than the first surface, the second detector elements being smaller in number than the first detector elements. Each of the second detector elements is reachable only by X-ray photons originating in a small angle range around a line connecting the X-ray source and a center of the surface of the detector element, the small angle range being determined by the predetermined distance separating the first and second surfaces and a size of the detector element.

Abstract: A method for performing reconstruction for a region of interest (ROI) of an object is provided. The method includes designating the ROI within the object, the ROI being located within a scan field of view (FOV) of a combined third- and fourth-generation CT scanner, the CT scanner including fixed photon-counting detectors (PCDs), and an X-ray source that rotates about the object in synchronization with a rotating detector. Further, the method includes determining, for each PCD, as a function of view angle, an on/off timing schedule, based on a size and location of the designated ROI, and performing a scan to obtain a first data set from the rotating detector and a second data set from the plurality of PCDs, while turning each PCD on and off according to the determined schedule. Finally, the method includes performing reconstruction using the first and second data sets to obtain ROI spectral images.

Abstract: A positron emission tomography (PET) scanner, including a first detector portion arranged circumferentially around a patient pallet, the first detector portion having a predetermined axial extent and transaxially subtending less than 360 degrees with respect to a central axis of the scanner defined by the first detector portion, wherein the first detector portion includes a plurality of first detector elements; and a second detector portion arranged separately from and opposing the first detector section, the second detector portion including a plurality of second detector elements, the second detector elements being of a different type than the first detector elements, wherein each of the first detector elements includes photomultiplier tubes (PMTs); and each of the second detector elements includes photosensors of a different type from the PMTs of the first detector elements.

Abstract: A photon-counting system includes photon-counting detectors that output photon-counting signals to indicate a number of photons impinging on the photon-counting detectors. The system also includes analog-to-digital conversion circuits, which convert one of the photon-counting signals into a digital photon-counting signals, and a processor that processes the digital photon-counting signals to extract information from the photon-counting signals. The information extracted can include a photon-counting rate. An intelligent multiplexer that, based on the photon-counting rate, modifies interconnection of the photon-counting detectors and analog-to-digital conversion circuits and provides digital photon-counting signals for a selected set of the analog-to-digital converters to the processor.

Abstract: A computed-tomography (CT) apparatus including a CT scanner including a rotating X-ray source, and a plurality of photon-counting detectors (PCDs) arranged in a fixed detector ring to capture incident X-ray photons emitted from the X-ray source. The plurality of PCDs includes a first plurality of first PCDs, each first PCD having a first collimator on a surface of the first PCD to block X-ray photons emitted from the X-ray source, the first collimator having openings of a first size, and a second plurality of second PCDs, each second PCD having a second collimator on a surface of the second PCD to block the X-ray photons emitted from the X-ray source, the second collimator having openings of a second size, the first size being different from the second size.

Abstract: A computed-tomography apparatus that includes a CT scanner including an X-ray source and a detector covering respective angle ranges in the axial and transaxial planes of the CT scanner. The CT detector includes first detector elements disposed on a first surface to capture incident X-ray photons emitted from the X-ray source, and second detector elements sparsely disposed on a second surface different from the first surface, the second surface being farther away from the scanner than the first surface, the second detector elements being smaller in number than the first detector elements. Each of the second detector elements is reachable only by X-ray photons originating in a small angle range around a line connecting the X-ray source and a center of the surface of the detector element, the small angle range being determined by the predetermined distance separating the first and second surfaces and a size of the detector element.

Abstract: A method for performing reconstruction for a region of interest (ROI) of an object is provided. The method includes designating the ROI within the object, the ROI being located within a scan field of view (FOV) of a combined third- and fourth-generation CT scanner, the CT scanner including fixed photon-counting detectors (PCDs), and an X-ray source that rotates about the object in synchronization with a rotating detector. Further, the method includes determining, for each PCD, as a function of view angle, an on/off timing schedule, based on a size and location of the designated ROI, and performing a scan to obtain a first data set from the rotating detector and a second data set from the plurality of PCDs, while turning each PCD on and off according to the determined schedule. Finally, the method includes performing reconstruction using the first and second data sets to obtain ROI spectral images.

Abstract: A method of fabrication of a collimator structure on a detector that includes applying a first layer of resist to a semiconductor sensor, applying a second layer of resist over the first layer of resist and the semiconductor sensor to cover both the first layer of resist and the semiconductor sensor, exposing the second layer of resist to ultraviolet (UV) light with a photomask to transfer a pattern from the photomask to the second layer of resist, removing portions of the second layer of resist corresponding to the pattern from the photomask to produce openings in the second layer of resist, which expose upper portions of the semiconductor sensor, and depositing a layer of metal in the openings and on the second layer of resist to cover the openings, the first layer of resist, the second layer of resist, and the semiconductor sensor.

Abstract: A positron emission tomography (PET) scanner, including a first detector portion arranged circumferentially around a patient pallet, the first detector portion having a predetermined axial extent and transaxially subtending more than 180 degrees, but less than 360 degrees with respect to a central axis of the scanner defined by the first detector portion; and a second detector portion arranged separately from and opposing the first detector section, the second detector portion having a radius of curvature smaller than a radius of curvature of the first detector portion, wherein the second detector portion transaxially subtends less than 180 degrees with respect to the central axis of the scanner.

Abstract: A spectral computed tomography scanner apparatus, including a rotating X-ray source, a plurality of fixed energy-discriminating detectors, a processor that generates a shadow map that indicates, for each detector/view angle, a shadow state of the detector, the shadow state indicating that one of X-rays are completely blocked by a second detector and do not reach the detector, the X-rays are partially blocked by the second detector and partially reach the detector, the X-rays are not blocked by any of the detectors and reach the detector, and the detector is not with the scan field of view at the view angle, and a controller configured to cause the scanner apparatus to perform a scan of an object over a first range of view angles to collect view data, wherein the processor is configured to perform scatter correction using the collected view data and the generated shadow map.

Abstract: A positron emission tomography scanner system that includes detector modules arranged adjacent to one another to form a cylindrical detector ring. Each of the detector modules includes an array of scintillation crystal elements, a plurality of photosensors arranged to cover the array of crystal elements and configured to receive light emitted from the array of crystal elements, and a fiber optics plate arranged between the array of scintillation crystal elements and the plurality of photosensors, the fiber optics plate including a plurality of fibers configured to guide the light emitted from the scintillation crystal to the plurality of photosensors.

Abstract: An apparatus and method for channel count reduction in solid-state-based positron emission tomography that multiplexes read-outs from photo-detectors using a sum delay circuit, including a sum channel and a delay-sum channel. The sum channel sums signals from sensors in an array and is digitized to extract the timing and energy information. A delay-sum channel includes a discrete delay line that introduces a known delay after each sensor, creating a time signature for the sensor, followed by a summing circuit that adds the delayed signals. The delay-sum channel is digitized using a high speed counters to extract location information. Start and Stop signals for the counter are derived when the sum channel output and the delay-sum channel output cross a pulse ID threshold, respectively. The pulse ID threshold is chosen to minimize the Compton scatter and not clip the photo-peak events.