Inverse-geometry CT. (a) 3D view. (b) Transverse view. The source array and detector arrays share the same axial extent, however the detector array is smaller in the transverse direction. The in-plane FOV is limited by the source size.
In-plane and axial views of the multieye IGCT system.
In-plane sinogram parameters of a single ray.
(a) Sinogram space coverage for a single view of the multieye IGCT system described in Table I, except with . Each detector array corresponds to a single parallelogram-shaped swath. (b) Sampling density across which is independent of view angle.
Geometry comparison between a multieye IGCT system and the NovaRay -arm system. The axis of rotation was shifted on the -arm system to simulate data that would be acquired by the outer detector arrays of a multieye IGCT system. The main discrepancy is the source array angle relative to the detector array.
Sampling density for the optimized multieye IGCT configuration outlined in Table I. (, ).
Collimator leakage decreases rapidly with increasing source spot spacing. The leakage due to the central focal spot location and a location quarter way from one end are very similar.
Transmission plot (logarithmic scale) for rays originating from the central source spot at various angles. Source spot spacing is .
The pre-patient collimator for a multieye IGCT system is composed of discrete layers. The area between the focal spots and the collimator material is composed of a substrate and cooling layer for the transmission target. The dashed arrows indicate layers with very little collimator material and thus may be left as air gaps. The solid arrows indicate the layers where the most significant amount of x-ray attenuation occurs.
(a) Filtered backprojection reconstruction from truncated data of the numerical torso phantom under a conventional third generation geometry. The detector size in this geometry is equivalent to the source size in the proposed multieye system. (b) Multieye IGCT reconstruction using only the central detector array data and (c) using only the outer detector array data. All images windowed to [, 1000] HU.
Multieye IGCT reconstruction using data from all detector arrays. (a) windowed to [, 1000] HU. (b) windowed to [, 150] HU.
(a) Wide-source single-eye reconstruction [, 1000] HU, ROI’s for noise comparison are indicated. (b) Single-eye reconstruction noise. (c) Multieye reconstruction noise. The noise images are windowed to [, 200] HU.
(a) First scan reconstruction with limited FOV. (b) Second scan reconstruction with the offset axis of rotation. Both images have the same window of [, 1000] HU.
Combined reconstruction with window widths of (a) 2000 HU and (b) 300 HU.
Proposed specifications for a multieye IGCT system.
NovaRay -arm specifications.
Standard deviation values comparing the large-source single-eye reconstruction to the multieye reconstruction.
Article metrics loading...
Full text loading...