BACKGROUND Septal penetration causes collimator-dependent differences in the heart-to-mediastinum (H/M) ratio in 123I-metaiodobenzylguanidine (MIBG) cardiac imaging. We investigated generally applicable methods to correct such differences. METHODS AND RESULTS Four hours after 123I-MIBG injection, 40 patients underwent anterior chest imaging successively with medium-energy (ME) and various non...

The study was undertaken to validate phantom-derived corrections for errors in collimation due to septal penetration or scatter, which vary with the size of the gastric region of interest (ROI). Six volunteers received 495 ml of 20% glucose labeled with both In-113m DTPA and Tc-99m DTPA. Gastric emptying of each nuclide was monitored by gamma camera as well as by periodic removal and reinstilla...

The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition protocols. Two radioactive sources were centrally and peripherally placed insid...

background: there is some evidence indicating improvement in myocardial performance after atrial septal defect closure, either device closure or surgical, but ventricular dyssynchrony has not been evaluated before and after surgical closure. the aim of this study was to evaluate ventricular mechanical dyssynchrony in patients with atrial septal defect before and after surgical closure. methods:...

OBJECTIVES This study was designed to determine the sensitivity and specificity of concealed entrainment (CE) for the identification of a critical isthmus in the atrium. BACKGROUND Isthmus identification during entrainment mapping of macro-reentrant atrial tachycardia (MRAT) relies on the demonstration of CE. METHODS Using the model of typical atrial flutter, entrainment was performed in 10...

The first signs of mobile commerce hype are here. Extremely rapid penetration and growth processes are predicted on the basis of some quick descriptions of mobile technology. The roots of these predictions are often found in markets with a low penetration rate of mobile technology. Nevertheless, it should be clear that without real substance in m-commerce products and services the investments i...

This paper gives an overview on the potentials of numerical simulations for understanding dynamics in laser material processing. After a short introduction into the model, simulation results on several processes like laser beam deep penetration welding, drilling or cutting are presented. Furthermore simulation results are compared with experimentally obtained data.

This paper analyzes the impact on mobile telephony diffusion patterns of the two predominant payment regimes, calling party pays (CPP) and receiving party pays (RPP), for mobile termination services. By applying instrumental variable techniques to panel data we account for a possible interdependency of penetration rates and regulatory interventions. For this purpose we use data on political and...

It is important for search and pay-per-click engines to penetration test their click fraud detection systems, in order to find potential vulnerabilities and correct them before fraudsters can exploit them. In this paper, we describe: (1) some goals and desirable qualities of a click fraud penetration testing system, based on our experience, and (2) our experiences with the challenges of buildin...