A prototype table-top inverse-geometry volumetric CT system
Proposed IGCT geometry shown with the x-ray beam at one position in the source array.
(a) The prototype table-top IGCT scanner. The prototype system source is larger than the detector in both dimensions. A subset of the source array (b) was used for all experiments, except for the noise experiments where (c) of the source were used.
(a) The 2D parallel-ray geometry to which the IGCT data are rebinned is illustrated using a virtual detector. is the projection view angle, is the tilt angle, and and are the coordinates within the projection. For comparison, two virtual detectors are shown, one with equal to and one with a smaller value of . (b) The four geometry parameters shown for a ray in the IGCT geometry where is the azimuthal angle. The view angle, , is equal to the sum of the azimuthal angle and the gantry rotation angle.
The defined coordinate system in (a) image space and (b) frequency space labeled with the investigated MTF profiles.
A comparison of the theoretical, simulated, and measured in-plane MTF curves.
A comparison of the theoretical and simulated slice MTF curves and the measured MTF which is slanted from the axis.
A coronal image of the Defrise phantom acquired by (a) the IGCT system and (b) the GE eXplore RS micro CT system. Significant cone-beam artifacts can be seen in the micro CT reconstruction.
Axial images of an inner ear specimen acquired by (a)–(c) the IGCT system and (d)–(f) a 16-slice scanner. Images were reconstructed with a standard kernel.
Axial images of two inner ear specimens acquired by (a) the IGCT system and (b) an eight-slice scanner. Both images were reconstructed with a bone-detail kernel.
The IGCT geometry with a misaligned axis of rotation depicted as a dashed line. The parameters , , , and define the location and orientation of the axis. The misalignment is exaggerated in this drawing.
Prototype IGCT system specifications.
Experimental setup (unless otherwise specified).
Reconstruction algorithm parameters (unless otherwise specified).
Results of noise investigation.
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