Tomographic image reconstruction using cross-plane rays
AssigneeGeneral Electric Company
InventorsHui Hu, Carl R. Crawford, Armin H. Pfoh, Jiang Hsieh
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Abstract
A CT apparatus employing a cone beam of x-rays reduces image artifacts by employing full as opposed to half scans of less than 360.degree.. The present invention recognizes that rays of a cone beam that cross the imaging plane are not redundant with opposing rays in the scan, as is the case with the rays within the imaging plane. In a second embodiment, half scans of less than 360.degree. are obtained using in-plane and cross-plane rays of the cone beam and the data from the in-plane rays is used to estimate the missing data from that collected with the cross-plane rays.
Claims3
A method of producing a tomographic image from projection data collected by a two-dimensional detector array receiving radiation along first rays perpendicular to a z-axis and second rays not perpendicular to the z-axis, said detector array producing first and second data indicating the intensities of the first and second rays respectively, comprising the steps of:
- a) collecting a first and second projection set comprising first and second projection data, respectively, over a range of gantry angles around the axis of less than 2.pi. radians and for a number of z-axis positions;
- b) estimating from the first projection set, values for the second projection set at the z-axis positions but at gantry angles not within the range of gantry angles, to produce a third projection set;
- c) combining the second and third projection sets to produce a completed projection set;
- and
- d) reconstructing the completed projection set and the first projection set to produce the tomographic image.
Dependencies are inferred from the claim text.