METHOD AND APPARATUS FOR LARGE FIELD OF VIEW IMAGING AND DETECTION AND COMPENSATION OF MOTION ARTIFACTS
First Claim
1. An apparatus for acquiring tomographic projection data at a plurality of angular positions relative to an object disposed in an examination region, the apparatus comprising:
- a radiation source;
a radiation sensitive detector which detects radiation emitted by the source that has traversed the examination region; and
a reconstructor;
wherein the apparatus is adapted to perform at least two scanning procedures of an object;
wherein at least a first scanning procedure is a centered geometry scanning procedure, wherein a center of the radiation sensitive detector is aligned with a center of rotation of the source and detector;
wherein at least a second scanning procedure is an offset geometry scanning procedure;
wherein a center of the radiation sensitive detector is displaced by a distance of approximately half a width of the detector or more from the center of rotation of the source and detector;
wherein projection data is acquired during the at least two scanning procedures including centered geometry projection data during the centered geometry scanning procedure and offset geometry projection data during the offset geometry scanning procedure; and
wherein the reconstructor reconstructs the projection data acquired during the at least two scanning procedures together to generate volumetric data indicative of the object.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus are provided to improve large field of view CT image acquisition by using at least two scanning procedures: (i) one with the radiation source and detector centered and (ii) one in an offset configuration. The imaging data obtained from both of the scanning procedures is used in the reconstruction of the image. In addition, a method and apparatus are provided for detecting motion in a reconstructed image by generating a motion map that is indicative of the regions of the reconstructed image that are affected by motion artifacts. Optionally, the motion map may be used for motion estimation and/or motion compensation to prevent or diminish motion artifacts in the resulting reconstructed image. An optional method for generating a refined motion map is also provided.
160 Citations
37 Claims
-
1. An apparatus for acquiring tomographic projection data at a plurality of angular positions relative to an object disposed in an examination region, the apparatus comprising:
-
a radiation source; a radiation sensitive detector which detects radiation emitted by the source that has traversed the examination region; and a reconstructor; wherein the apparatus is adapted to perform at least two scanning procedures of an object; wherein at least a first scanning procedure is a centered geometry scanning procedure, wherein a center of the radiation sensitive detector is aligned with a center of rotation of the source and detector; wherein at least a second scanning procedure is an offset geometry scanning procedure;
wherein a center of the radiation sensitive detector is displaced by a distance of approximately half a width of the detector or more from the center of rotation of the source and detector;wherein projection data is acquired during the at least two scanning procedures including centered geometry projection data during the centered geometry scanning procedure and offset geometry projection data during the offset geometry scanning procedure; and wherein the reconstructor reconstructs the projection data acquired during the at least two scanning procedures together to generate volumetric data indicative of the object. - View Dependent Claims (3, 4, 6, 7, 8, 9, 10, 11)
-
-
2. (canceled)
-
5. (canceled)
-
12. A computed tomography imaging method, comprising the steps of:
-
performing at least two scanning procedures of an object, including; acquiring projection data during at least one centered geometry scanning procedure in which a center of the radiation sensitive detector is aligned with a center of rotation of the source and detector; and acquiring projection data during at least one offset geometry scanning procedure in which a center of the radiation sensitive detector is displaced from the center of rotation of the source and detector by a distance of approximately half a width of the detector or more; acquiring projection data during the at least two scanning procedures including centered geometry projection data during the centered geometry scanning procedure and offset geometry projection data during the offset geometry scanning procedure; and reconstructing the projection data acquired during the at least two scanning procedures together to generate volumetric data indicative of the object. - View Dependent Claims (14, 15, 17, 18, 19)
-
-
13. (canceled)
-
16. (canceled)
-
20. An apparatus for generating a motion map, the apparatus comprising:
-
a radiation source; a radiation sensitive detector which detects radiation emitted by the source that has traversed an examination region; and a reconstructor an image processor; wherein the radiation source and the radiation sensitive detector are used to acquire projection data at a plurality of angular positions relative to an object disposed in the examination region; wherein the reconstructor is used to generate a reference image from the projection data; wherein reference projection data is obtained from a forward projection of the reference image; wherein differences between the acquired projection data and the reference projection data are computed to determine line integral differences; and wherein the image processor uses the line integral differences to generate a motion map indicative of the regions of a corresponding image reconstructed from the projection data that are affected by motion. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
-
-
31. A method for generating a motion map, the method comprising the steps of:
-
acquiring projection data at a plurality of angular positions relative to an object disposed in an examination region; reconstructing from the projection data to generate a reference image; obtaining reference projection data from a forward projection of the reference image; computing differences between the acquired projection data and the reference projection data to determine line integral differences; and using the line integral differences to generate a motion map indicative of the regions of a corresponding image reconstructed from the projection data that are affected by motion. - View Dependent Claims (32, 33, 34, 35, 36, 37)
-
Specification