Abstract: A collimator for a computed tomography imaging device can include first and second leaves positioned on opposing sides of a primary radiation delivery window. The first and second leaves can include first and second gratings having a plurality of attenuating members with a plurality of secondary radiation delivery windows extending between adjacent attenuating members.

Abstract: A method for a practical model based computed tomography construction may include assuming that a filtered back projection reconstruction of a computed tomography image is available and acquiring a deviate of a multivariate random variable computed tomography data set. A filtered back projection reconstruction of the image may be estimated, and the filtered back projection reconstruction may be identified as a deviate of a multivariate random variable. A maximum a posteriori estimate may be generated for the filtered back projection reconstruction.

Abstract: A method of contrast-enhanced computed tomography (CT) imaging can include repeatedly scanning a target region at a frequency during a session, the frequency initially being a first rate. After detecting an increase of the attenuation of radiation by a contrast-enhanced first structure within a target region, the frequency can be increased to a second rate. After detecting a subsequent decrease in the attenuation, the frequency can be decreased to a third rate.

Abstract: A collimator for a computed tomography imaging device can include first and second leaves positioned on and bounding opposing sides of a radiation delivery window. The first and second leaves can be movable to adjust at least one of a size or a location of the primary radiation delivery window relative a the radiation source in a direction non-parallel to an axis of rotation of the radiation source.

Abstract: A collimator for a computed tomography imaging device can include first and second leaves positioned on opposing sides of a primary radiation delivery window. The first and second leaves can include first and second gratings having a plurality of attenuating members with a plurality of secondary radiation delivery windows extending between adjacent attenuating members.

Abstract: A method of contrast-enhanced computed tomography (CT) imaging can include repeatedly scanning a target region an applied power during a session. The applied power can be a first power for a first scan. After the first scan, the applied power for each of a plurality of scans can be selected based on an algorithm. The algorithm can be based on, for example, the attenuation indicated from a preceding scan in the session.

Abstract: A collimator for a computed tomography imaging device can include first and second leaves positioned on opposing sides of a primary radiation delivery window. The first and second leaves can include first and second gratings having a plurality of attenuating members with a plurality of secondary radiation delivery windows extending between adjacent attenuating members.

Abstract: A method for a practical model based computed tomography construction may include assuming that a filtered back projection reconstruction of a computed tomography image is available and acquiring a deviate of a multivariate random variable computed tomography data set. A filtered back projection reconstruction of the image may be estimated, and the filtered back projection reconstruction may be identified as a deviate of a multivariate random variable. A maximum a posteriori estimate may be generated for the filtered back projection reconstruction.

Abstract: For filtered back-projection of a projection image data set, the projection image data set is cosine-weighted. The cosine-weighted projection image data set within the image plane of the projection image data set is subjected to a two-dimensional Radon transformation. The Radon transform of the cosine-weighted projection image data set differentiated with respect to the distance from an image origin of an image coordinate system. The derivative of the Radon transform is redundancy-weighted. The redundancy-weighted derivative is subjected to a two-dimensional Radon back-transformation. The Radon back-transform is differentiated and back-projected with respect to an image column coordinate. A differentiation step width entering into the differentiation is varied depending on depth.

Abstract: A collimator for a computed tomography imaging device can include first and second leaves positioned on and bounding opposing sides of a radiation delivery window. The first and second leaves can be movable to adjust at least one of a size or a location of the primary radiation delivery window relative a the radiation source in a direction non-parallel to an axis of rotation of the radiation source.

Abstract: A method of contrast-enhanced computed tomography (CT) imaging can include repeatedly scanning a target region at a frequency during a session, the frequency initially being a first rate. After detecting an increase of the attenuation of radiation by a contrast-enhanced first structure within a target region, the frequency can be increased to a second rate. After detecting a subsequent decrease in the attenuation, the frequency can be decreased to a third rate.

Abstract: A collimator for a computed tomography imaging device can include first and second leaves positioned on opposing sides of a primary radiation delivery window. The first and second leaves can include first and second gratings having a plurality of attenuating members with a plurality of secondary radiation delivery windows extending between adjacent attenuating members.

Abstract: A method of contrast-enhanced computed tomography (CT) imaging can include repeatedly scanning a target region an applied power during a session. The applied power can be a first power for a first scan. After the first scan, the applied power for each of a plurality of scans can be selected based on an algorithm. The algorithm can be based on, for example, the attenuation indicated from a preceding scan in the session.

Abstract: For filtered back-projection of a projection image data set, the projection image data set is cosine-weighted. The cosine-weighted projection image data set within the image plane of the projection image data set is subjected to a two-dimensional Radon transformation. The Radon transform of the cosine-weighted projection image data set differentiated with respect to the distance from an image origin of an image coordinate system. The derivative of the Radon transform is redundancy-weighted. The redundancy-weighted derivative is subjected to a two-dimensional Radon back-transformation. The Radon back-transform is differentiated and back-projected with respect to an image column coordinate. A differentiation step width entering into the differentiation is varied depending on depth.

Abstract: Certain embodiments provide staggered circular scans for CT imaging. In certain embodiments, a CT imaging system comprises a plurality of source-detector assemblies that are axially offset from one another and rotate about a rotation axis to provide staggered circular CT scanning.

Abstract: Certain embodiments provide staggered circular scans for CT imaging. In certain embodiments, a CT imaging system comprises a plurality of source-detector assemblies that are axially offset from one another and rotate about a rotation axis to provide staggered circular CT scanning.

Abstract: The image reconstruction is implemented along theoretical ?-lines, wherein the theoretical ?-lines not only lead to interpolated detector data but also can emanate from interpolated source positions. Interpolation thus occurs both at the detector and at the source.

Abstract: Embodiments of the present invention include a method and apparatus for accurate cone beam reconstruction with source positions on a curve (or set of curves). The inversion formulas employed by embodiments of the method of the present invention are based on first backprojecting a simple derivative in the projection space and then applying a Hilbert transform inversion in the image space.

Abstract: A helical conebeam computed tomography imaging system includes an x-ray source (12) that produces an x ray conebeam, and an x-ray detector array (16) that detects the x ray conebeam after passing through an examination region (14). The x-ray detector array (16) generates projection data in a detector coordinate system defined with reference to the detector array (16). A derivative processor (60) computes a derivative of the projection data with respect to a helix angle of the helical trajectory at fixed projection direction to generate differentiated projection data. A convolution processor (64) convolves the differentiated projection data with a kernel function to produce filtered projection data. The convolving is performed in the detector coordinate system. A backprojector (42, 82) backprojects the filtered projection data to obtain an image representation.