Background: The Shielding methods in radiotherapy due to delivering an accurate radiation dose to cancer tissues and avoiding unnecessary dose to normal tissues are very important. These methods include Lead standard blocks, individual molding and multi leaf collimator (MLC). The MLC method is not still common in Iran radiotherapy centers. Individual molding is better than the lead block shield...

The primary purpose of this report is to review the general principles of shielding during computed tomography (CT) and to summarize the latest published information on shielding efficacy. Currently, there are discordant opinions within the literature regarding the appropriateness of shielding, particularly with regard to in-plane bismuth. Understanding that the decision to implement use of a p...

In this paper, it is demonstrated how anisotropic and inhomogeneous magnetic metamaterials may be used for molding the flow of the magnetic field, considering magnetic field shielding as the main application of practical interest. It is shown that using anisotropic materials, magnetic field shielding may be improved, and this anisotropy can be realized by metamaterials. Introducing additional i...

Recently, the development of electronic and electric devices has caused an increase in the level of electromagnetic radiation; therefore, the demand for protection against this danger has increased. There are many ways how to ensure the protection of device against electromagnetic interference; however, this paper is devoted just one of the ways, the shielding. The paper is focused on calculati...

The NMR signals of 113Cd have been observed in powder samples of the cadmium halides CdF,, CdCl2, CdBr2 '4H20, Cdl 2 , of the cadmium chalcogenides CdO, CdS, CdSe, CdTe and of CdC03 . For m C d in CdCl2 , CdBr2-4H20, CdS and in CdSe anisotropics of the nuclear magnetic shielding have been detected. The shielding tensor in these powders is axially symmetric. For the other specimens no anisotropi...

Structural and magnetic properties of purine and pyrimidine nucleotides (CMP, UMP, dTMP, AMP, GMP, IMP) were studied at different levels of ab initio molecular orbital theory. These calculations were performed at the hartree-fock level and density functional B3LYP methods. Geometries were fully optimized by following Cs symmetry restrictions. The standard 6-31G** basis set which includes polari...

Abstract The requirement for accelerated and quantitatively accurate screening of nuclear magnetic resonance spectra across the small molecules chemical compound space is two-fold: (1) a robust ‘local’ machine learning (ML) strategy capturing effect neighborhood on an atom’s ‘near-sighted’ property—chemical shielding; (2) reference dataset generated with state-of-the-art first-principles method...

Progress of the shielding calculation of the Super-FRS is reported here. At least as important as the shielding of the target area is the determination of the shielding in the region of the first dipoles as the part of the primary beam that will not interact in the target will be stopped here. The Monte-Carlo-method with FLUKA [1] used for the shielding assessment here has already been describe...

Using solid state multiple pulse techniques the magnetic shielding tensors a of the F nuclei in a single crystal of KZnF 3 have been measured. The F~-site symmetry in KZnF3 , D 4 h , allows axial anisotropy of a and determines fully the principal shielding directions. Using CaF 2 as the reference compound, the average shielding is + 85 ppm and the shielding anisotropy is + 18.4 ppm. These resul...