Introduction: Human beings are naturally exposed to ionizing radiation in any environment. There are two main contributors to radiation exposures from natural sources: cosmic rays, Cosmo genic radionuclides, and radioactive nuclides that originated in the earth's crust. According to the latest data provided by the United Nations Scientific Committee on the Effects of Atomic Rad...

patients and methods we evaluated radiation exposure from initial and downstream testing in a prospectively collected, matched cohort evaluated for cp in the emergency department (ed) with either ccta compared with usual care over a median follow-up of 19.6 months. effective radiation dose was calculated using published conversion factors. results prospective, ecg-triggered acquisition using a ...

introduction: to measure radiation exposures rate in low-risk patients having stress-only and stress-rest myocardial perfusion imaging. methods: this was a prospective study conducted from january 2012 till november 2012 upon patients with low pre-test probability for coronary artery disease (cad). a stress mpi (stress-only if mpi is normal and no resting study) followed by a resting mpi study...

introduction the exposure of human beings to ionizing radiation from natural sources is a continuing and inescapable feature of life on earth. for most individuals, this exposure exceeds that from all man-made sources combined. materials and methods in this study, the annual effective dose in high level environmental background radiation areas (hlebras) of northern city of ramsar in iran was de...

This paper is a theory-guided exploratory study of teaching and learning strategies that firms use to transfer of collective knowledge between organizations. Collective knowledge is knowledge that is both tacit and embedded in intra-firm group activities. We first discuss the benefits of group teaching and group learning in transferring collective knowledge from a source community to a recipien...

The radiation survey of the ambient environment was conducted using two gamma detectors and the measurement results were used in the computation of the mean external radiation dose rate, mean weighted dose rate, annual effective dose and the collective effective dose, which are 69 nGy h, 0.447 mSv y, 237 μSv and 0.126 × 10 man Sv y, respectively. A hyper purity germanium (HPGe) detector was use...