摘要:
In one aspect, the present invention is a method for automatically positioning an object, such as a patient, on a movable table using pre-scan scout data. High and low edges and a center of the object are determined as a function of object position in a z-axis direction. At least one threshold is determined from which to determine whether to move the table. The table is automatically repositioned based on comparison of the thresholds to respective distances of the high edge, low edge and center of the object from isocenter. The above described method allows automatic and dynamic adjustment of the table height to a position that prevents over-range while allowing use of higher gains to reduce image noise.
摘要:
A method for obtaining data includes scanning an organ with an imaging system emitting X-rays and modulating the emitted X-rays with an organ specific bowtie addition.
摘要:
A system and method of diagnostic imaging with reduced x-ray exposure to the scan subject during scanning includes acquiring a set of cardiac signals or other motion (cardiac mechanical motion or respiratory motion) related signals and determining and imaging profile therefrom. Pursuant to the imaging profile, voltage applied to an x-ray source is modulated to provide an energizing voltage during primary data acquisition stages and a reduced voltage during secondary or non-data acquisition stages. Voltage modulation repeats until sufficient data for image reconstruction has been acquired.
摘要:
A CT imaging system and method are provided in which groups of adjacent detector elements of a detector array are ganged in an x-direction; and an object is scanned using the ganged groups of adjacent detector elements to acquire projection data. In one embodiment, to reduce degradation of images resulting from the ganged detector elements, an image of the object is reconstructed utilizing the acquired projection data and an adjusted iso-channel of the multislice detector array different from an iso-channel defined for scans performed without utilizing ganged groups of detector elements.
摘要:
A CT system includes a rotatable gantry having an opening for receiving an object to be scanned, and a controller configured to apply a first kVp for a first time period, apply a second kVp for a second time period, wherein the second time period is different from the first time period, acquire a first asymmetric view dataset during at least a portion of the first time period, acquire a second asymmetric view dataset during at least a portion of the second time period, and generate an image using the acquired first and second asymmetric view datasets.
摘要:
A method of manufacturing a collimator mandrel having variable attenuation characteristics is presented. The manufacturing process includes the placement of a layer of attenuating material on a core of base material. The layer of attenuating material is relatively thin and varies in thickness circumferentially around the core. The collimator mandrel may be manufactured by placing a cast about a core of non-attenuating material, filling a void between the cast and the core with an attenuating material, allowing the material to cure, and removing the cast from the assembly.
摘要:
A system and method of diagnostic imaging is provided that includes determining a position of a subject in a scanning bay and tailoring x-ray attenuation such that the specific position of the subject is taken into consideration. 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, in one embodiment, a method for determining tracking control parameters for positioning an x-ray beam of a computed tomography imaging system having a movable collimator positionable in steps and a detector array including a plurality of rows of detector elements. The method includes steps of obtaining detector samples at a series of collimator step positions while determining a position of a focal spot of the x-ray beam; determining a beam position for each detector element at each collimator step utilizing the determined focal spot positions, a nominal focal spot length, and geometric parameters of the x-ray beam, collimator, and detector array; and determining a calibration parameter utilizing information so obtained. For example, in determining a target beam position at which to maintain the x-ray beam, a detector element differential error is determined according to ratios of successive collimator step positions; and a target beam position is selected for an isocenter element in accordance with the determined element differential errors.
摘要:
Methods and apparatus for reducing spectral artifacts in a computed tomography (CT) system are described. In one embodiment, the CT system includes a plurality of multislice detector modules, a detector housing and a collimator adjacent the detector modules. Each detector module is mounted to the detector housing and includes a scintillator array. The collimator includes a plurality of plates that are positioned so that a x-ray beam shadow is centered over gaps in the scintillator array. In operation, the collimator separates the x-ray beams so that the scintillator gaps are protected and the x-ray beams are prevented from projecting through the scintillator array elements along a shortened length path.
摘要:
The present invention is, in one aspect, an imaging system having a detector that has multiple detector cells extending along a z-axis, the detector being configured to collect multiple slices of data; and a scalable data acquisition system configured to convert signals from the detector to digital form, the scalable data acquisition system having a plurality of converter boards each with a plurality of channels, the channels and detector cells having an interweaved coupling to reduce susceptibility to band artifact.