摘要:
Quantum detection efficiency and spatial resolution in a kinestatic charge detector are improved by utilization of an x-ray transmissive device positioned within a collection volume of a kinestatic charge detector x-ray detection chamber for displacing the charge carrier generating medium within predetermined areas of the chamber. Within the chamber, quantum detection efficiency and spatial resolution are affected by distortion in electric field lines existing between a high voltage anode and a relatively low voltage collector electrode. The distorted field lines cause charge carriers generated in the medium by impinging radiation to impact on either the walls of the chamber or to follow non-linear paths between the point of creation and the collection electrode. By displacing the medium in the chamber in areas having the greatest electric field distortion, the quantum detection efficiency and spatial resolution are improved. In one embodiment an x-ray transmissive device is placed in the chamber adjacent an x-ray emitting window and has a portion extending partially into the space between the anode and collector electrode. In another embodiment, an additional device is positioned in the chamber adjacent a rear wall thereof for displacing the medium in the rear portion of the chamber.
摘要:
An apparatus for detecting propogating energy in a defined space includes a medium disposed within the space which interacts with the incident propogating energy to produce secondary energy. An electrostatic field is impressed across the defined space for directing the secondary energy toward a planar detector located at one end of the space. Adjacent the detector is positioned a planar grid for preventing the secondary energy from being detected by the detector prior to passage through the grid. The grid comprises a three layer device having a middle layer formed of an electrically insulative sheet material of a relatively stiff structure. The other two layers comprise conductive layers on opposed surfaces of the first layer which are connected to an electric potential for creating a field across the grid structure and a further field between the grid structure and the detector for accelerating the secondary energy toward the detector in the area of the grid at a space between the grid and detector.
摘要:
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.
摘要:
Cast collimators for use in CT imaging systems are described, as are methods of making them. Such collimators may comprise pre-patient collimators, pre-patient filter/collimator assemblies, and/or post-patient collimators. The filters and/or collimators may be made of any suitable high-density, high atomic number material such as lead, a lead alloy, tantalum, tungsten, tungsten suspended in an epoxy matrix, tungsten suspended in a slurry, or the like. Embodiments of these collimators comprise specially-designed channels and vanes that allow them to be precision cast to the necessary degree of accuracy. These channels and vanes are preferably tapered. These collimators and filter/collimator assemblies help minimize the x-ray dose to the patient by minimizing the scattered radiation creation mechanism and by collimating out much of the scattered radiation that would otherwise be subjected to the patient. These collimators may be cast as either single piece structures, or multiple pieces that can be operatively connected together.
摘要:
A diagnostic imaging system includes a high frequency electromagnetic energy source that emits a beam of high frequency electromagnetic energy toward an object to be imaged. An energy discriminating (ED) detector receives high frequency electromagnetic energy emitted by the high frequency electromagnetic energy source. The ED detector includes a direct conversion layer dynamically operable in a photon counting mode in one view and in an integrating mode in another view and an indirect conversion layer. A data acquisition system (DAS) is operably connected to the ED detector and a computer operably connected to the DAS.
摘要:
A diagnostic imaging system includes a high frequency electromagnetic energy source that emits a beam of high frequency electromagnetic energy toward an object to be imaged. An energy discriminating (ED) detector receives high frequency electromagnetic energy emitted by the high frequency electromagnetic energy source. The ED detector includes a direct conversion layer dynamically operable in a photon counting mode in one view and in an integrating mode in another view and an indirect conversion layer. A data acquisition system (DAS) is operably connected to the ED detector and a computer operably connected to the DAS.
摘要:
A system and method of diagnostic imaging is provided that includes positioning a subject in an imaging device, collecting positioning information of the subject from at least one sensor disposed in proximity of the imaging device, and determining a relative position of the subject within the imaging device from at least the position information. The present invention automatically selects a proper attenuation filter configuration, corrects patient centering, and corrects noise prediction errors, thereby increasing dose efficiency and tube output.
摘要:
The present invention is a directed to a CT detector for a CT imaging system that incorporates a segmented optical coupler between a photodiode array and a scintillator array. The segmented optical coupler also operates as a light collimator which improves the light collection efficiency of the photodiode array. The segmented optical coupler is defined by a series of reflector elements that collectively form a plurality of open cells. The open cells form light transmission cavities and facilitate the collimation of light from a scintillator to a photodiode. The cavities may be filled with optical epoxy for sealing to the photodiode array.
摘要:
A method and system of counting and tagging radiation energy received by a radiation detector is presented. The method and system are designed to dynamically control the sampling window or shaping time characteristics of a photon counting detector to accommodate variations of flux experienced by the detector so as to preserve optimum detector performance and prevent saturation during high flux conditions.
摘要:
A system and method of diagnostic imaging is provided that includes positioning a subject in a scanning bay, comparing a center of mass of the subject to a reference point, and repositioning the subject in the scanning bay to reduce a difference in position between the center of mass of the subject and the reference point. The present invention automatically selects a proper attenuation filter configuration, corrects patient centering, and corrects noise prediction errors, thereby increasing dose efficiency and tube output.