Introduction: Ordered subset expectation maximization (OSEM), is an effective iterative method for SPECT image reconstruction. The aim of this study is the evaluation of the role of system matrix in OSEM image reconstruction method using four different physical beam radiation models with three detection configurations. Methods: SPECT was done with an arc of 180 deg...

Purpose Reconstructed PET images are typically noisy, especially in dynamic imaging where the acquired data divided into several short temporal frames. High noise reconstructed translates to poor precision/reproducibility of image features. One important role “denoising” is therefore improve precision However, typical denoising methods achieve reduction at expense accuracy. In this work, we pre...

At the experimental heavy ion therapy facility at the GSI Darmstadt an in-beam PET scanner is operated for quality assurance monitoring simultaneously to the therapeutic irradiation. A fully 3D maximum likelihood expectation maximization (MLEM) reconstruction algorithm has been developed and adapted to the special conditions of in-beam PET [1]. The system response function (system matrix) for t...

We have developed an image quality theory for reconstruction that we apply to filtered back-projection (FBP) and statistical reconstruction (OSEM) for Single Photon Emission Computed Tomography (SPECT). Quantitative measures of reconstruction performance are given in terms of signal and noise power spectra, SPS and NPS, that we derive from phantom images. This allows evaluating the properties o...

The sequence requirement of the ACGT-containing abscisic acid response element (ABRE) was analyzed by systematically substituting the bases surrounding the ACGT-core of motif A, the principal ABRE of the rice gene, OSEM: This was done within the context of a 55-bp promoter fragment that minimally confers ABA-responsiveness to a heterologous promoter. Based on this analysis, the sequence require...

A fully 3D iterative image reconstruction algorithm has been developed for high-resolution PET cameras composed of pixelated scintillator crystal arrays and rotating planar detectors, based on the ordered subsets approach. The associated system matrix is precalculated with Monte Carlo methods that incorporate physical effects not included in analytical models, such as positron range effects and...

PURPOSE Investigate the possibility of reducing the number of PET detector elements per ring (introduce gaps) while maintaining image quality by employing compressed sensing techniques. METHODS A uniform Ge-68 phantom was imaged on a D-RX PET/CT scanner twice; once with all detectors operational (baseline) and once with 8 equidistant detector blocks turned off (partially sampled [PS], 11% det...

The purpose of this study was to analyze the behavior of a contouring algorithm for PET images based on adaptive thresholding depending on lesions size and target-to-background (TB) ratio under different conditions of image reconstruction parameters. Based on this analysis, the image reconstruction scheme able to maximize the goodness of fit of the thresholding algorithm has been selected. A ph...

BACKGROUND P-glycoprotein [Pgp] dysfunction may be involved in neurodegenerative diseases, such as Alzheimer's disease, and in drug resistant epilepsy. Positron emission tomography using the Pgp substrate tracer (R)-[11C]verapamil enables in vivo quantification of Pgp function at the human blood-brain barrier. Knowledge of test-retest variability is important for assessing changes over time or ...