BACKGROUND To evaluate the interchangeability of perfusion parameters obtained with help of models used for post-processing of perfusion-CT images in pancreatic adenocarcinoma and to determine the mean values and ranges of perfusion in different tumour gradings. METHODS Perfusion-CT imaging was performed prospectively in 48 consecutive patients with pancreatic adenocarcinoma. In 42 patients b...

Psychophysiological interaction (PPI) is a regression based method to study task modulated brain connectivity. Despite its popularity in functional MRI (fMRI) studies, its reliability and reproducibility have not been evaluated. We investigated reproducibility and reliability of PPI effects during a simple visual task, and examined the effect of deconvolution on the PPI results. A large open-ac...

Image deconvolution is still to be a challenging illposed problem for recovering a clear image from a given blurry image, when the point spread function is known. Although competitive deconvolution methods are numerically impressive and approach theoretical limits, they are becoming more complex, making analysis, and implementation difficult. Furthermore, accurate estimation of the regularizati...

A new deconvolution method for Auger electron spectroscopy is presented. This method is based on a non-linear least squares minimizing routine (Levenberg-Marquardt) and global approximation using splines, solving many of the drawbacks inherent to the Van Cittert and Fourier transform based deconvolution methods. The deconvolution routine can be run on a personal computer. The application of thi...

In this work, we evaluated three iterative deconvolution algorithms and compared their performance to partial volume (PV) correction based on structural imaging in brain positron emission tomography (PET) using a database of Monte Carlo-simulated images. We limited our interest to quantitative radioligand PET imaging, particularly to (11)C-Raclopride and striatal imaging. The studied deconvolut...

In conventional Compton camera systems, the image reconstruction is performed only in two-dimensional or three-dimensional spatial coordinates for a specific gamma-ray energy. By doing so, a priori knowledge of the incident gamma-ray energy is required, and usually an energy window is applied to select full energy deposition events. In some other applications, spectral-deconvolution algorithms ...

The paper presents a survey of error-free algorithms to solve various systems of linear equations. The presented algorithms do not introduce computational errors into the solution and thus they are well suited to solve ill-conditioned linear systems. The error-free algorithms are based on modulo arithmetic. Two basic approaches have been investigated in the paper. The first one is based on iter...

Introduction: Orbital gamma-ray and neutron spectroscopy measurements have greatly contributed to our understanding of the elemental composition of the both the Moon and Mars [1,2,3,4,5]. One drawback , however, to these measurements is that the spatial resolution is quite broad since it is roughly equal to or greater than the spacecraft height above the planetary surface. For example, for the ...

Efforts have been devoted to maximizing memory array densities. However, as the devices are scaled down in dimension and getting closer to each other, electrical interference phenomena among devices become more prominent. Various features of 3-D memory devices are proposed for the enhancement of memory array density. In this study, we mention 3-D NAND flash memory device having pillar structure...

The infrared spectra of polysaccharides (amylose and cellulose) as well as of their constituent monosaccharides (αand βD-glucose) and the results of their deconvolution are presented. The number of bands separated upon deconvolution in the 1200-920 cm spectral range exceeds the number of visualized absorption maxima in the room temperature spectra by a factor of more than two. It is shown that ...