background when a primary radiation interacts with a medium, the secondary radiations are produced, that the contribution of these secondary radiation should considered in the calculation of dose. build-up factor is a dosimetric correction factor to assume effect of secondary radiation in calculation of dose. calculation of this factor is very difficult and time consuming. due to significance o...

background: radiology staff needs to justify the radiation exposures in order to protect themselves and others from radiation risks. the aims of this study were to examine the awareness level of radiation dose and protection amongst radiographers and to compare their performance between major jordanian hospitals. materials and methods: a cross-sectional survey was conducted in 4 major jordanian...

A general form of the polarization matrix valid for any type of electromagnetic radiation (plane waves, multipole radiation etc.) is defined in terms of a certain bilinear form in the field-strength tensor. The quantum counterpart is determined as an operator matrix with normal-ordered elements with respect to the creation and annihilation operators. The zero-point oscillations (ZPO) of polariz...

The purpose of this study was to assess the level of patient radiation dose received in general fluoroscopy examinations, compare the findings with the international diagnostic reference levels (IDRLs), and establish the initial institutional (local) LDRLs. A comprehensive survey was conducted for general fluoroscopy examinations using the medical records of a Radiology Department of a leading ...

We argue that the well-known problem of the instabilities associated with the self-forces (radiation reaction forces) in classical electrodynamics are possibly stabilized by the introduction of gravitational forces via general relativity.

A group of stars embedded in an emission nebula near the cluster NGC 7822 has been discovered to have a unique interstellar spectrum, characterized by exceedingly strong CN lines. Evidence is presented favoring the hypothesis that the CN molecules arise in the immediate neighborhood of the H 11 region boundary. It is further suggested that the CN molecules are formed in the solid particles of t...

The high density medium that characterizes the central regions of starburst galaxies and its power to accelerate particles up to relativistic energies make these objects good candidates as γ-rays sources. In this paper, a self-consistent model of the multifrequency emission of the starburst galaxy NGC 253, from radio to gamma-rays, is presented. The model is in agreement with all current measur...

2014 The critical dose measured for polyethylene single crystals at 2 MV is increased by a factor of 4 between 300 K and 20 K. Below 100 K the intermediate hexagonal crystalline phase was not observed. From these measures, the number of cross-links created, factor G, was calculated, and it appeared to be proportional to temperature. Finally, we propose a new model tempting to explain the influe...