Programa de Engenharia Nuclear, Universidade Federal do Rio de Janeiro (PEN/COPPE, UFRJ), Ilha do Fundão, Caixa Postal 68590, CEP 21945-970, Rio de Janeiro, Brazil.
Published: May 2014
AI Article Synopsis
Article Abstract
The activity concentration of a solution of (99)Tc was absolutely determined by liquid scintillation measurements based on the triple-to double-coincidence ratio method (TDCR) and compared with the results given by 4πβ(LS)-γ(NaI) live-timed anticoincidence (with extending dead-time) and classical 4πβ(PC)-γ(NaI) coincidence counting systems based on using (60)Co as the efficiency-tracing radionuclide. The results of anticoincidence and coincidence counting are, respectively, 0.18% and 0.66% higher than the result from TDCR measurements, but they are consistent within uncertainties.
The massic activity of Ac in 0.1 mol/L HCl was measured by multiple primary methods over four consistent measurement campaigns. Results from the triple-to-double coincidence ratio (TDCR) method of liquid scintillation (LS) counting were in accord with other LS-based primary methods.
Background: Assessing the performance of spectral detectors is an important but nontrivial problem. In the past few years, detective quantum efficiency-(DQE)-like quantities have been proposed that allow quantifying the spatial-spectral performance for certain tasks. In previous publications, we have presented and validated an approach to determine detector properties like the modulation transfer function (MTF), the noise power spectrum (NPS), and the DQE based on an end-to-end Monte Carlo model of the detection process.
Division of Functional Imaging, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, 277-8577, Japan.
Objective: To investigate the clinical utility of a new anthropomorphic phantom that reproduces the chest and abdomen better than the conventional National Electrical Manufacturers Association (NEMA) body phantom, count rates and image quality of PET images obtained from patients were evaluated.
Methods: Anthropomorphic phantoms were used to include radioactivity in the lung, liver, kidney, and background regions. Two NEMA body phantoms were used for chest and abdominal assessments.
Introduction: Critical coronavirus disease (COVID-19) patients have a high mortality rate. To identify high-risk patients, first-level healthcare facilities can use the neutrophil-lymphocyte ratio (NLR) and the plateletlymphocyte ratio (PLR) as prognostic markers. We aimed to assess the NLR and the PLR profile in critically ill COVID-19 patients to predict disease severity.
The review summarizes the results of previous and the latest studies on aromaticity and related concepts. The electron counting rule for 3D-aromatic systems 2(n + 1) is shown to be a generalization of the 4n + 2 rule for planar molecules, and, vice versa, the latter can be derived from the former. The relative stability of the push-pull and captodative aromatic systems is shown to depend on the nature of the groups separated by the C=C bond in geminal or vicinal positions.
