Abstract: Among other things, a detector unit for a detector array of a radiation imaging modality is provided. In some embodiments, the detector unit comprises a radiation detection sub-assembly and an electronics sub-assembly. In some embodiments, at least some portions of the detector unit, such as the electronics sub-assembly, may be formed via a semiconductor fabrication technique. By way of example, an electronics sub-assembly may be formed via a semiconductor fabrication technique and may comprise electronic circuitry which is embedded in a molding compound. In some embodiments, such electronic circuitry may be electrically coupled together via electrically conductive traces and/or vias.

Abstract: One or more techniques and/or systems described herein provide for a detector array having an effective size that is larger than its actual size of its elements, thus reducing costs by reducing materials required. In one embodiment, one or more channels of the detector array are removed (e.g., and filled with a radiation absorbing material) to create what may be referred to as a sparse array. In another embodiment, one or more channels of a detector array comprise a detection portion and a dead space (e.g., filled with a radiation absorbing material). In yet another embodiment, one or more channels of a detector array comprise light focusing mechanisms configured to focus light from a scintillator portion of an indirect conversion detector array to a photodetector portion of the detector array, where a detection surface area of the photodetector is less than a detection surface area of the scintillator.

Abstract: One or more metal printing techniques are described for generating a three-dimensional metal structure, such as a one-dimensional or two-dimensional anti-scatter grid. The techniques comprise applying a thin layer of powdered metal onto a printing area and using a binder (which is printed onto the printing area according to a specified pattern) to bind the powdered metal particles together. The acts of applying powdered metal and a binder may be repeated a plurality of times until a three-dimensional metal structure having a specified height is created. Moreover, in one embodiment, once the layering is complete, another binder is applied to the one or more layers to provide strength and/or support. While heat may be used in some embodiments to activate one or more of the applied binders the three-dimensional metal structure is generally not heated to a melting point of the powdered metal.

Abstract: One or more techniques and/or systems described herein provide for a detector array having an effective size that is larger than its actual size of its elements, thus reducing costs by reducing materials required. In one embodiment, one or more channels of the detector array are removed (e.g., and filled with a radiation absorbing material) to create what may be referred to as a sparse array. In another embodiment, one or more channels of a detector array comprise a detection portion and a dead space (e.g., filled with a radiation absorbing material). In yet another embodiment, one or more channels of a detector array comprise light focusing mechanisms configured to focus light from a scintillator portion of an indirect conversion detector array to a photodetector portion of the detector array, where a detection surface area of the photodetector is less than a detection surface area of the scintillator.

Abstract: Among other things, one or more systems and/or techniques for integrating electrical charge yielded from an indirect conversion detector array of a pulsating radiation system are provided. The integration begins during a resting period between a first and second pulse and ends before the second pulse is emitted. Electrical charge that is measured during a resting period is integrated, while electrical charge measured during a pulse is not integrated. In this way, parasitic contributions caused by the direct interaction of radiation photons with a photodiode are reduced and a quantum efficiency of the indirect conversion detector array is increased, for example. Moreover, the period of integration can be adjusted such that a voltage gain related to the indirect conversion detector array can be varied to a predetermined level.

Abstract: Anti-scatter plates are used to attenuate secondary radiation so that it is not detected by a detector array. However, anti-scatter plates often cast dynamic shadows on the detector array which results in noise in signals produced by the detector array. As disclosed herein, an anti-scatter grid comprises at least two anti-scatter plates. A percentage difference in the shadows cast by the first and the second anti-scatter plates is substantially zero (e.g., causing uniform percentage change in shadows cast on the detector array). Additionally, the shadows that are cast by the anti-scatter plates may be substantially static. In one embodiment, this is accomplished by having a top surface of an anti-scatter plate that has a transverse dimension that is less than a bottom surface of the anti-scatter plate.

Abstract: One or more metal printing techniques are described for generating a three-dimensional metal structure, such as a one-dimensional or two-dimensional anti-scatter grid. The techniques comprise applying a thin layer of powdered metal onto a printing area and using a binder (which is printed onto the printing area according to a specified pattern) to bind the powdered metal particles together. The acts of applying powdered metal and a binder may be repeated a plurality of times until a three-dimensional metal structure having a specified height is created. Moreover, in one embodiment, once the layering is complete, another binder is applied to the one or more layers to provide strength and/or support. While heat may be used in some embodiments to activate one or more of the applied binders the three-dimensional metal structure is generally not heated to a melting point of the powdered metal.

Abstract: Among other things, one or more systems and/or techniques for integrating electrical charge yielded from an indirect conversion detector array of a pulsating radiation system are provided. The integration begins during a resting period between a first and second pulse and ends before the second pulse is emitted. Electrical charge that is measured during a resting period is integrated, while electrical charge measured during a pulse is not integrated. In this way, parasitic contributions caused by the direct interaction of radiation photons with a photodiode are reduced and a quantum efficiency of the indirect conversion detector array is increased, for example. Moreover, the period of integration can be adjusted such that a voltage gain related to the indirect conversion detector array can be varied to a predetermined level.

Abstract: An x-ray detector assembly includes a first substrate and a second substrate. An array of photodetectors, which have coplanar contacts, are disposed on the top surface of the first substrate. The x-ray detector assembly further includes a plurality of x-ray scintillator elements arranged in an array. The photodetectors are aligned so as to match the array of x-ray scintillator elements. The second substrate is fused to the bottom surface of the first substrate. The second substrate provides on its distal side a planar connectivity pattern matched to electronics of a signal acquisition system. One or more through-hole connections traverse both substrates, and are configured to couple the contacts of the photodetectors from the top surface of the first substrate to the connectivity pattern on the distal side of the second substrate.

Abstract: A method and system is presented in radiography for optimizing image quality of an object (e.g. an anatomical region of a patient), while minimizing the radiation dose to the patient. X-ray exposure parameters, such as operating voltage (kVp), operating current (mA), focal spot size, and soft x-ray filter combination, are dynamically controlled during the x-ray exposure. During at least two different sampling intervals and at two different kVp levels, x-rays are passed through the object, and detected by sensors located between the object and the image plane. After the last sampling interval, the sensor output signals and the measured thickness of the object are used to evaluate the optimal settings for the x-ray exposure parameters. The x-ray exposure parameters are set to these optimal settings for the remainder of the exposure period.

Abstract: A dual-energy x-ray detector includes a plurality of x-ray detector elements that detect x-rays that are generated by an x-ray source and that have passed through an object. Each of the x-ray detector elements includes a first scintillator layer adapted to convert x-rays from the x-ray source that have passed through the object into light of a first wavelength, and a second scintillator layer positioned behind the first scintillator layer and adapted to convert x-rays from the x-ray source that have passed through the object and through the first scintillator layer into light of a second wavelength. Each of the x-ray detector elements further includes a first optical sensor having a spectral sensitivity substantially matched to light of the first wavelength, and a second optical sensor having a spectral sensitivity substantially matched to light of the second wavelength.

Abstract: An x-ray detector assembly includes a first substrate and a second substrate. An array of photodetectors, which have coplanar contacts, are disposed on the top surface of the first substrate. The x-ray detector assembly further includes a plurality of x-ray scintillator elements arranged in an array. The photodetectors are aligned so as to match the array of x-ray scintillator elements. The second substrate is fused to the bottom surface of the first substrate. The second substrate provides on its distal side a planar connectivity pattern matched to electronics of a signal acquisition system. One or more through-hole connections traverse both substrates, and are configured to couple the contacts of the photodetectors from the top surface of the first substrate to the connectivity pattern on the distal side of the second substrate.

Abstract: A dual-energy x-ray detector includes a plurality of x-ray detector elements that detect x-rays that are generated by an x-ray source and that have passed through an object. Each of the x-ray detector elements includes a first scintillator layer adapted to convert x-rays from the x-ray source that have passed through the object into light of a first wavelength, and a second scintillator layer positioned behind the first scintillator layer and adapted to convert x-rays from the x-ray source that have passed through the object and through the first scintillator layer into light of a second wavelength. Each of the x-ray detector elements further includes a first optical sensor having a spectral sensitivity substantially matched to light of the first wavelength, and a second optical sensor having a spectral sensitivity substantially matched to light of the second wavelength.

Abstract: An x-ray detector having an increased DQE (detective quantum efficiency) is provided. The x-ray detector includes a scintillator for converting incident x-ray photons into optical photons, and an epitaxial p-i-n photodiode for converting these optical photons into an electric signal. The epitaxial photodiode includes a low resistivity N+ type silicon substrate; a high-resistivity, N-type epitaxial layer that forms the intrinsic region of the photodiode; and a light-receiving P+ type layer. The resistivity of the N+ layer is sufficiently low, so that the diffusion lengths of the charge carriers that are formed in the N+ layer by direct conversion of x-rays are small enough to allow these charge carriers to recombine before reaching the pn junction. The resistivity of the epitaxial N-layer is high enough so that the collection efficiency of the output signal resulting from the electron-hole pairs created through absorption of the optical photons in the depletion region is not impaired.

Abstract: A method and system is presented in radiography for optimizing image quality of an object (e.g. an anatomical region of a patient), while minimizing the radiation dose to the patient. X-ray exposure parameters, such as operating voltage (kVp), operating current (mA), focal spot size, and soft x-ray filter combination, are dynamically controlled during the x-ray exposure. During at least two different sampling intervals and at two different kVp levels, x-rays are passed through the object, and detected by sensors located between the object and the image plane. After the last sampling interval, the sensor output signals and the measured thickness of the object are used to evaluate the optimal settings for the x-ray exposure parameters. The x-ray exposure parameters are set to these optimal settings for the remainder of the exposure period.

Abstract: A computed tomography system having a fourfold improvement in both short-and long-term beam position stability. A beam-position detector is located at a peripheral edge of the primary fan beam and is fixed relative to the primary detectors so as to indicate beam position on the primary detectors. The beam-position detector is oriented so that its maximum sensitivity to beam motion is in the direction of beam movement due to focal spot drift due to thermal effects and gravity. Short-term focal spot drift is detected by a secondary beam out of the primary fan beam and is corrected in real time by adjusting the position of a collimator for the primary beam. Long-term changes in the focal spot position are corrected by using information from the beam-position detector to recalibrate the focal spot-beam collimator data set.

Abstract: An x-ray scanning system including an x-ray source defining a focal spot from which radiation is emitted, an x-ray detector assembly including a plurality of x-ray detectors cooperative with the x-ray source to define a radiation beam extending from the focal spot to all of the detectors, a support for supporting at least one of the x-ray source and the detector assembly for rotation about an isocenter, and means for configuring the detectors so that the increment in radial distance from the isocenter to the centers of any two adjacent sub-beams is a substantially constant value.

Abstract: In an x-ray scanning system having an x-ray source and an x-ray detector assembly, including a plurality of x-ray detector crystals grouped in substantially linear arrays and cooperative with the x-ray source, a substantially continuous radiation detection zone is established by positioning the detector arrays so that substantially all radiation from the source passing through the detector assembly passes through at least a portion of at least one detector crystal. The detector arrays are tilted at a preselected angle .alpha. with respect to a nominally perpendicular orientation relative to radial lines extending from the focal spot, so that the spaces between adjacent detector crystals in an array are not aligned with x-rays emanating from the x-ray source. The angle .alpha. is a function of the geometry of the detector crystals and the spaces between adjacent crystals in an array.

Abstract: In an x-ray scanning system having an x-ray source and a plurality of x-ray detectors mounted in substantially linear arrays and positioned along an arc extending about a focal spot defined by the x-ray source, the placement of the arrays along the arc is optimized to substantially avoid interfering contact between adjacent arrays. Each detector array is located at a preselected radial distance from the focal spot and oriented at a preselected angle with respect to radial lines extending from the focal spot so that the radiation-insensitive end portions of adjacent arrays overlap in the tangential direction. The tangential spacing between adjacent detector arrays is thus approximately equal to the tangential spacing between adjacent detectors in a single array.

Abstract: The invention provides a system for and method of precalibrating the position of the focal spot of an X-ray tube before its installation in a CT scanner system so that the focal spot of the tube is properly aligned with the off-focal aperture, slice-defining aperture and detectors of the scanner system. The precalibration is performed using an interface registration support that receives the X-ray tube and supports the X-ray tube on a mount provided in either the precalibration system or the scanner system. The mount of the precalibration system duplicates the mount of the scanner system, so that desired position of the focal spot in the scanner system relative to the scanner system mount is duplicated in the precalibration system relative to the precalibration system mount.