To utilize the synergy between CT and MR datasets from an object at the same time, a unified dual-modality image reconstruction approach is proposed using a dual-dictionary learning technique. The key is to establish a knowledgebased connection between these two datasets for a tight fusion of different imaging modalities. Our scheme consists of three inter-related elements: dual-dictionary learning, CT image reconstruction, and MR image reconstruction. Our experiments show that even with highly under-sampled MR data and few x-ray projections, we can still satisfactorily reconstruct both MR and CT images. This approach can be potentially useful for a CT-MRI system.
Multiple-source cone-beam scanning is a promising mode for dynamic volumetric CT/micro-CT. The
first dynamic CT system is the Dynamic Spatial Reconstructor (DSR) built in 1979. The pursuance for
higher temporal resolution has largely driven the development of CT technology, and recently led to
the emergence of Siemens dual-source CT scanner. Given the impact and limitation of dual-source
cardiac CT, triple-source cone-beam CT seems a natural extension for future cardiac CT. Our work
shows that trinity (triple-source architecture) is superior to duality (dual-source architecture) for helical
cone-beam CT in terms of exact reconstruction. In particular, a triple-source helical scan allows a
perfect mosaic of longitudinally truncated cone-beam data to satisfy the Orlov condition and yields
better noise performance than the dual-source counterpart. In the (2N+1)-source helical CT case, the
more sources, the higher temporal resolution. In the N-source saddle CT case, a triple-source scan
offers the best temporal resolution for continuous dynamic exact reconstruction of a central volume.
The recently developed multi-source cone-beam algorithms include an exact backprojection-filtration
(BPF) approach and a "slow" exact filtered-backprojection (FBP) algorithm for (2N+1)-source helical
CT, two fast quasi-exact FBP algorithms for triple-source helical CT, as well as a fast exact FBP
algorithm for triple-source saddle CT. Some latest ideas will be also discussed, such as multi-source
interior tomography and multi-beam field-emission x-ray CT.
In this paper, a hybrid helix-saddle trajectory scanning mode is proposed for bolus-chasing CT angiography. By combining the conventional helical trajectory and saddle trajectory appropriately, an optimal curve can be obtained with a capability of localized volumetric imaging at desirable locations. In this context, a condition for the PI-line existence is determined. Then, both filtered-backprojection (FBP), backprojection filtration (BPF) and reduced-scan FBP algorithms are developed. Numerical studies with the 3D Shepp-Logan phantom support the validity and merits of the
proposed trajectories and associated algorithms.
In this paper, we propose an exact shift-invariant filtered backprojection (FBP) algorithm for triple-source saddle-curve
cone-beam CT. In this imaging geometry, the sources are symmetrically positioned along a circle, and the trajectory of each x-ray source is a saddle. Then, we extend Yang's formula from the single-source case to the triple-source case. The saddles can be divided into four parts to specify four datasets. Each of them contains three data segments associated with different saddles. Then, images can be reconstructed on the planes orthogonal to the z-axis. Each plane intersects the
trajectories at six pointes which can be used to define the filtering directions. With our triple-source approach, the scanning time is only one-third of that with the single-source saddle trajectory, and the reconstructed image quality is excellent in our numerical studies. These new features are important for cardiac imaging and small animal imaging.
From element automatic control view, we propose a configuration algorithm for three-level cross-connects in data plane to handle with bypass, grooming and local add/drop traffic of fiber-level, band-level and wavelength-level by a abstract bipartite graph of MG-OXC and bandwidth utilization spectra graph. The configuration algorithm is evaluated by computer simulation as well as validated by experiment on our flexible Multi-functional Optical Switching Testbed (MOST).
To solve the scalability and flexibility issue in current optical network testbeds, a Multi-functional Optical Switching Testbed (MOST) has been built. Benefiting from design of modular hardware and layered software, network experiments of scalability and complicated node architecture can be made based on it. The hardware and software structure of the MOST system is explicitly analyzed in the article and demonstrations of a 12-node ASON and shared wavelength conversion ASON on MOST are also reported.
A novel method called data plane shared ring scheme (DPSRS) is proposed in IP over automatic switched transport networks (ASTN) overlay network. Based on the novel scheme, explicit analysis on related network architecture, edge node structure and operation process are made. For decision of bandwidth restriction parameters two algorithms are also proposed.