Toshiba Medical Systems Corporation

Kabushiki Kaisha Toshiba

Be-Shan Chiang

Satoru Nakanishi

Alexander A Zamyatin

Thomas Labno

Yu Zou

Michael D Silver

Katsuyuki Taguchi

Naruomi Akino

Aleksandr Zamyatin

Alex Zamyatin

Mike Silver

Cone beam artifacts arise in circular CT reconstruction. The cone beam artifacts are substantially removed by reconstructing a reference image from measured data at circular source trajectory, generating synthetic data by forward projection of the reference image along a pre-determined source trajectory, which supplements the circular source trajectory to a theoretically complete trajectory, reconstructing a correction image from the synthetic data and applying a scaling factor whose value is adaptively determined and optimized based upon the minimization of a predetermined cone beam artifact metric. Ultimately, the cone beam artifact is substantially reduced by generating a corrected image using the reference image and the correction image that has been optimally scaled based upon the adaptively determined scaling factor value.

Method and system for substantially reducing cone beam artifacts based upon adaptive scaling factor in circular computer tomography (CT)

Cone beam artifacts arise in circular CT reconstruction. The cone beam artifacts are substantially removed by reconstructing a reference image from measured data at circular source trajectory, differentiating the reference image; generating synthetic data by forward projection of the differentiated reference image along a pre-determined source trajectory, which supplements the circular source trajectory to a theoretically complete trajectory, reconstructing a correction image from the synthetic data and optionally applying a scaling factor. Ultimately, the cone beam artifact is substantially reduced by generating a corrected image using the reference image and the correction image that has been optimally scaled based upon the adaptively determined scaling factor value.

Method and system for substantially reducing cone beam artifacts based upon image domain differentiation in circular computer tomography (CT)

Cone beam artifacts arise in circular CT reconstruction. The cone beam artifacts are substantially removed by reconstructing a reference image from measured data at circular source trajectory, generating synthetic data by forward projection of the reference image along a pre-determined source trajectory, which supplements the circular source trajectory to a theoretically complete trajectory, reconstructing a correction image from the synthetic data and substantially reducing the cone beam artifacts by generating a corrected image using the reference image and the correction image.

Method and system for substantially reducing artifacts in circular cone beam computer tomography (CT)

A method of computed-tomography and a computed-tomography apparatus where the portion of the field of view of a subject were full scan data is available is reconstructed using a full-scan algorithm. In the areas where full scan data is not available, half-scanning is used. Data is also extrapolated from the full scan data. The extrapolated data overlaps a portion of the half-scanning data. The extrapolated data and the overlapped portion of the half-scanning data are feathered. The image is reconstructed using the full-scan, half-scan and feathered data. Corner regions in an image are exposed and reconstructed to produce more uniform z-coverage of the reconstruction field of view.

Method for circular scan reconstruction in computed tomography and computed tomographic device

As an illustration of generating a motion map, although the cardiac CT is described for selecting an optimal phase, the disclosure is not limited to the cardiac CT. For the cardiac CT, the cardiac phase map is efficiently generated based upon helical scan data, and the optimal phase is selected within a reasonable time. At the same time, the optimal phase is accurately determined based upon complementary rays as indexes for minimal movement so as to select the projection data for minimizing artifacts in reconstructed cardiac images. The helically scanned data reflect motion within the same cardiac cycle or over the continuous cardiac cycles. The application of the complementary ray technique to the helically scanned data is accomplished by three-dimensionally determining a pair of the complementary rays in order to take into account motion within the same cardiac cycle or over the continuous cardiac cycles. The absolute sum of the differences for the top ray and or the bottom ray is determined in order to determine the amount of cardiac motion.

Automatic motion map generation in helical CT

A method of reconstructing a volume image of an object includes receiving circle projection data collected by a detector along a circular path with respect to the object; receiving line projection data collected by the detector along a linear path with respect to the object; producing a reconstructed circle path volume image of the object from the pre-processed circle projection data using a reconstruction algorithm that includes a ramp filter; producing a reconstructed line path volume image of the object from pre-processed line projection data using a reconstruction algorithm that includes a Hubert filter; and combining the reconstructed circle path volume image and the reconstructed line path volume image to produce the volume image of the object. An apparatus and computer program product are also described.

Method and system for tomographic reconstruction in medical imaging using the circle and line trajectory

Embodiments and processes of computer tomography perform tasks associated with weighting projection data based upon at least one motion index such as electrocardiogram gated reconstruction, view-based motion map and ray-based motion map. Other embodiments and processes of computer tomography perform tasks associated with weighting projection data based upon at least one motion index and another index that is associated with certain geometric characteristics of a cone beam.

Motion weighting in computed tomography (CT) with cone angle

A method for obtaining data from CT scans, including obtaining projection data from at least one detector row in a CT system; applying a weighting function including cone-angle dependent weight to projection data; filtering weighted data; and backprojecting weighted data while accounting for cone-angle. The method finds application to an X-ray CT apparatus, including a helical scanning device configured to collect projection data while at least one of a gantry and a couch moves along an axial direction, the helical scanning device including an X-ray source to generate X-rays, and a detector having detector elements arranged in rows along the axial direction to produce projection data; and a processor, which includes a weighting device to apply a weighting function including cone-angle dependent weight to projection data, thereby obtaining weighted data, a filtering device to filter weighted data, and a backprojecting device to backproject weighted data while accounting for cone-angle.

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Buffalo Grove, IL, United States of America

Be-Shan Chiang