Abstract: 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.

Abstract: There is therefore provided, in one aspect, a method for imaging an object utilizing a computed tomographic (CT) imaging system having a rotating gantry, a multislice detector array on the rotating gantry and using at least n>1 rows of detector channels, and a radiation source on the rotating gantry configured to project a beam of radiation towards the multislice detector array through an object to be imaged. The method includes helically scanning the object with the CT imaging system at a pitch p>n to acquire projection data from the n rows of detector channels; applying a combined helical weight and conjugate weight to at least a portion of the acquired projection data to produce virtual projection data compensating for incomplete helical row data of the acquired projection data; and reconstructing an image of the object utilizing the acquired projection data and the virtual projection data.

Abstract: 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.

Abstract: In one embodiment, the present invention is a method for positioning an x-ray beam on a multi-slice detector array of an imaging system in which the detector array has rows of detector elements and is configured to detect x-rays in slices along a z-axis. The method includes steps of comparing data signals representative of x-ray intensity received from different rows of detector elements and positioning the x-ray beam in accordance with a result of the comparison.

Abstract: A method and processor for running a pulse sequencing program to perform the method for use with a multi-slice CT system wherein the system includes detector elements arranged in rows for collecting data corresponding to separate slices of an object to be imaged, the system also including fewer acquisition channels than detector elements wherein the method includes alternately connected each acquisition channel to at least first and second elements to acquire data corresponding to each element that can subsequently be combined to form a separate image for each element row in the array.

Abstract: In one embodiment, the present invention is a method for positioning an x-ray beam on a multi-slice detector array of an imaging system in which the detector array has rows of detector elements and is configured to detect x-rays in slices along a z-axis. The method includes steps of comparing data signals representative of x-ray intensity received from different rows of detector elements in first and second element subsets where the first and second subsets are located at opposite ends of the detector array and positioning the x-ray beam in accordance with a result of the comparisons.

Abstract: 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.

Abstract: In one embodiment of the present invention, a method is provided for analyzing performance of tracking control loop in a CT imaging system configured to position an x-ray beam using the tracking control loop. The method includes the steps of collecting control loop data over a plurality of views during scanning and of evaluating control loop data relative to the corresponding views to measure at least one imaging system characteristic. This method provides the imaging system user with data that facilitates insight into possible causes for imaging artifacts. In another embodiment, a CT imaging system is provided including a tracking control loop. The CT imaging system is configured to position an x-ray beam using the tracking control loop, collect control loop data over a plurality of views during scanning and evaluate control loop data relative to the corresponding views to measure at least one imaging system characteristic.

Abstract: 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.

Abstract: A method is described for optimizing signal-to-noise performance of an imaging system, including the steps of scout-scanning an object to obtain scout scan data; determining a plurality of normalized x-ray input signal factors using the scout scan data; using the normalized x-ray input signal factors to determine at least one system input signal; selecting at least one gain for the object scan using the system input signal; and applying the selected gain corresponding to the system input signal in the object scan.

Abstract: The present invention, in one form, is an imaging system which, in one embodiment, utilizes a filter assembly including a plurality of filter portions for altering the intensity and quality of an x-ray beam. Specifically, in one embodiment, by positioning the filter assembly so that the x-ray beam is filtered by the first portion of the filter assembly, the x-ray beam is altered to perform a body portion scan. By positioning the filter assembly to the second portion, the x-ray beam is altered to perform a head portion scan.

Abstract: In one embodiment, the present invention is a method for positioning an x-ray beam on a multi-slice detector array of an imaging system in which the detector array has rows of detector elements and is configured to detect x-rays in slices along a z-axis. The method includes steps of comparing data signals representative of x-ray intensity received from different rows of detector elements in first and second element subsets where the first and second subsets are located at opposite ends of the detector array and positioning the x-ray beam in accordance with a result of the comparisons.

Abstract: The present invention, in one form, is a system which, in one embodiment, utilizes a pre-patient filter to attenuate detector array signals to indirectly determine a voltage applied to an x-ray source. Specifically, in one embodiment, the pre-patient filter includes a plurality of attenuating portions. By radiating an x-ray beam from the x-ray source through the different attenuating portions of the filter, the signals intensities at a detector array are attenuated differently. Utilizing an attenuation reference for the filter and a ratio of the measured attenuated signal intensities, the voltage applied to the x-ray source may indirectly be determined.

Abstract: 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.

Abstract: 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.

Abstract: The present invention, in one form, is a system which, in one embodiment, corrects for position errors of an x-ray beam caused by dynamic movement and thermal drift of the imaging system. More specifically, signals from a detector array are utilized to determine a dynamic movement error to correct for errors caused by the rotation of a gantry and a thermal drift error to correct for imaging system x-ray beam movement errors. In one embodiment, a pre-patient collimator is utilized to alter the z-axis position of the x-ray beam as determined by the dynamic movement and the temperature error profiles.

Abstract: 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.

Abstract: The present invention, in one form, is a system for correcting thermal drift in an imaging system. More specifically, a correction algorithm determines an adjusted focal spot position based upon a first temperature focal spot position and a second temperature focal spot position. The adjusted focal spot position is utilized in the reconstruction process to correct for focal spot movement resulting from thermal drift.

Abstract: The present invention, in one form, is a system which, in one embodiment, utilizes signals from a detector array to verify system dose. More specifically, the detector array signal intensities are used to determine image noise and a collimator aperture to verify an x-ray dosage. Particularly, in one embodiment, the signals intensities from the detector array are used to determine the position of collimator cams. Using the position of the collimator cams, the aperture of the collimator is determined so that X-ray dose may verified using the collimator aperture and image noise information.

Abstract: Scintillators having a geometric configurations that substantially prevent x-ray beams from passing entirely through a gap between adjacent scintillators are described. More particularly, if the scintillators are cut on an angle to form parallelogram or trapezoidal shapes, or if the detector module is tilted in the x-ray beam z-axis, an x-ray beam will not pass through a non-scintillating gap between adjacent scintillators over the range of focal spot positions. Such scintillators have an increased geometric efficiency compared to known scintillator constructions.