During the last decade, technical developments in myocardial perfusion single photon emission tomography (SPET) imaging systems have significantly improved the accuracy of diagnosing coronary artery disease. Nevertheless, the patient's position and/or the acquisition protocol can affect the studies' quality, possibly leading to misdiagnoses. In HJNM and in other journals the importance of prope...

Three-dimensional (3D) region of interest (ROI) imaging with C-arm systems provides anatomical information in a predefined 3D target region at a considerably low X-ray dose. A necessary initial step prior to a 3D acquisition is to isocenter the patient with respect to the target to be scanned. To this end, two low-dose fluoroscopic X-ray acquisitions are usually applied from anterior-posterior ...

Model reduction is a major issue for control, optimization and simulation of large-scale systems. We present a formal procedure for model reduction of perturbed linear second-order differential equations. Second-order equations appear in a variety of physical contexts, e.g., in molecular dynamics or structural mechanics to mention just a few. Common spatial decomposition methods such as Proper ...

Fan-beam collimators are used in single-photon-emission computed tomography (SPECT) to improve the sensitivity for imaging of small organs. The disadvantage of fan-beam collimation is the truncation of projection data surrounding the organ of interest or, in those cases of imaging large patients, of the organ itself, producing reconstruction artifacts. A spatially varying focal length fan-beam ...

In this paper, the problem of full state approximation by model reduction is studied for stochastic and bilinear systems. Our proposed approach relies on identifying dominant subspaces based reachability Gramian a system. Once desired subspace computed, reduced order then obtained Galerkin projection. We prove that, in case, either preserves mean square asymptotic stability or leads to models w...

Fan-beam collimators are used in single photon emission computed tomography to improve the sensitivity for imaging of small organs. The disadvantage of fan-beam collimation is the truncation of projection data surrounding the organ of interest or, in those cases of imaging large patients, of the organ itself producing reconstruction artifacts. A spatially varying focal length fan-beam collimato...

In this paper, we reinvestigate the solution for chaotic time series prediction problem using neural network approach. The nature of this problem is such that the data sequences are never repeated, but they are rather in chaotic region. However, these data sequences are correlated between past, present, and future data in high order. We use Cascade Error Projection (CEP) learning algorithm to c...

Submitted to the Journal of Computational Physics Seven schemes to maintain the r B = 0 constraint numerically are compared. All these algorithms can be combined with shock-capturing Godunov type base schemes. They fall into three categories: the eight-wave formulation maintains the constraint to truncation error, the projection scheme enforces the constraint in some discretization by projectin...