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- Enzhuo Quan, D. Lalush
- IEEE Nuclear Science Symposium Conference Recordâ€¦
- 2005

We study reconstruction methods and resolution effects in a proposed multi-source X-ray micro-computed tomography (CT) system. The proposed device is based on dense arrays of microfabricated field-emission X-ray sources which are individually addressable. The proposed system has two 10 cm linear arrays of X-ray sources, each with 50 sources spaced at 2 mm.â€¦ (More)

The relationship between the choice of parameters for a generalized Gibbs prior for the MAP-EM (maximum a posteriori, expectation maximization) algorithm and the model of the projection/backprojection process used in SPECT (single photon emission computed tomography) reconstruction is studied. A realistic phantom, derived from an X-ray CT study and averageâ€¦ (More)

We investigate the effect of dual parallel plane orbits on pinhole reconstruction quality. Projections taken of a micro-Defrise phantom for two parallel, circular orbits are reconstructed using an OSEM algorithm. We hypothesize that a dual parallel orbit scan will provide greater coverage for pixels that do not lie in the orbit plane, thus reducing theâ€¦ (More)

- Wen-Tung Wang, B. Tsui, D. Lalush, Chiraporn Tocharoenchai, E. Frey
- IEEE Transactions on Nuclear Science
- 2005

In /sup 201/Tl//sup 99m/Tc dual-isotope simultaneous-acquisition (DISA) myocardial imaging, crosstalk due to Tc photons results in significant contamination of the Tl data. The objective of this work is to seek the acquisition parameters (i.e., energy window width and center) that have the optimal tradeoff between minimizing the crosstalk and maximizing theâ€¦ (More)

- S. Sayeram, D. Lalush
- 2007 Computers in Cardiology
- 2007

The purpose of this study is to evaluate 4D reconstruction methods for the processing of gated cardiac single photon emission computed tomography (SPECT) images from obese patients. Clinical gated SPECT projection data were reconstructed using the ordered-sub sets expectation- maximization (OS-EM) and the 4D reseated block- iterative maximum a posterioriâ€¦ (More)

- Enzhuo Quan, D. Lalush
- 2006 IEEE Nuclear Science Symposium Conferenceâ€¦
- 2006

We present a faster iterative reconstruction algorithm based on the ordered-subset convex (OSC) algorithm for transmission CT. The OSC algorithm was modified such that it calculates the normalization term before the iterative process in order to save computational cost. The modified version requires only one backprojection per iteration as compared to twoâ€¦ (More)

- D. Lalush, Ramya Rajaram, Enzhuo Quan, Jian Zhang, Jianping Lu, Otto Zhou
- 2006 IEEE Nuclear Science Symposium Conferenceâ€¦
- 2006

We study the effects of geometric design on the reconstruction of 3D images from an X-ray tomosynthesis system using microfabricated discrete X-ray sources. Carbon-nanotube-based field-emission X-ray sources can be fabricated in arrays; however, little is known about the effects of the geometry of such a system on reconstruction of tomosynthesis data. Weâ€¦ (More)

- D. Lalush
- The 26th Annual International Conference of theâ€¦
- 2004

We study in simulation the properties of a transmission CT system using two fan-beam sources both illuminating a single detector. Using traditional X-ray sources, such a system would be expensive, slow, and unwieldy. With the development of new X-ray sources based on nanofabrication methods, however, such a dual-source system becomes feasible. The principalâ€¦ (More)

We investigate the effect of multiple circular orbits offset transaxially to improve truncation artifacts. A simulated phantom was placed at a distance from a pinhole collimator that ensured transaxial truncation for the projections. To compensate this truncation, two pinhole scans were then simulated with the axes of rotation (AOR) shifted symmetricallyâ€¦ (More)

- W.P. Segars, D. Lalush, E. Frey, Dinesh Manocha, M. A. King, B. Tsui
- IEEE Transactions on Nuclear Science
- 2009

We previously developed a realistic phantom for the cardiac motion for use in medical imaging research. The phantom was based upon a gated magnetic resonance imaging (MRI) cardiac study and using 4D non-uniform rational b-splines (NURBS). Using the gated MRI study as the basis for the cardiac model had its limitations. From the MRI images, the change in theâ€¦ (More)

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