Introduction: During radiotherapy, high accuracy in the dose delivery is required because there is a strong  relationship between the absorbed dose, local tumor control and particularly the normal tissue damage. In  many institutions, in vivo dosimetry using diodes is performed to check the actual dose delivered. In general,  the uncertainty in the dose delivered should fall within  ± 5% of the...

Background: The compositions of Ferrous sulphate, Agarose and Xylenol orange dye (FAX) and Ferrous sulphate, Gelatin and Xylenol orange dye (FGX) in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. Ionizing radiation causes oxidation of Fe2+ ion to Fe3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours af...

objective: the aim of this study was to investigate the translucency of resin-modified glass-ionomer cements (rmgic) and polyacid-modified composite resin (pcmr) over a period of one year. materials and methods: the study was done on three rmgic (fuji ii lc, photac-fil aplicap and vitremer) and one pcmr (dyract). a conventional gic (fuji cap ii) and two composite resins (tetric and z 100) were ...

introduction spect projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. backscatter constitutes a major part of the scatter contamination in lower energy windows. the current study is an evaluation of the effect of backscatter material on fwhm and image quality investigated by monte carlo simulation. materials and methods simind program...

‘Press finger' in atraumatic restorative treat­ ment (ART) is used to spread a glass ionomer cement (GIC) to seal the restoration margin and adjacent pits and fissures. This study compared the spreadability of Fuji IX® and Ketac®-Molar to establish which was best suited for this purpose. Twenty equally spaced cavities (35 mm apart) were machinecut in each of two Perspex slabs 200 x 100 x 20 mm....

The dynamics of the vitreous body induced by eye rotations is studied experimentally. In particular, we consider the case in which the vitreous cavity is filled by a Newtonian fluid, either because the vitreous is liquefied or because it has been replaced, after vitrectomy, by a viscous fluid. We employ a rigid Perspex container which models, in a magnified scale, the vitreous cavity of the hum...

Axial pumps have a wide range of applications, and cavitation is one of the main causes of there performance degradation. So, the present study investigates experimentally and numerically the performance of cavitating axial pumps. In this study a three-dimensional Navier-Stokes code was used (CFDRC, 2004) to model the two-phase flow field around a four blades axial pump. The governing equations...

Attainment of an improved bodily posture is of the utmost importance if the general resistance of the individual to the infection is to be upgraded. The typical posture of rheumatoid arthritis is one of fatigue, with " poking chin," drooping shoulders, flat chest with poor respiratory excursion, visceroptosis, sway-back from the waist, flexed knees, and pronated feet. The key-note of the correc...

To develop a numerical method for the description of the flow field around a Björk-Shiley (BS) standard valve prosthesis in aortic position, detailed experimental measurements and numerical calculations are performed under steady flow conditions. The experiment was conducted at Reynolds numbers up to 800. In order to perform LDA measurement of velocity in the vicinity of the valve with a curved...

The underlying objective of the present study is to increase gas-solids contact in a circulating fluidized bed by the introduction of obstacles in the riser portion. The presence of such obstacles leads to suppression of radial inhomogeneities in the solids mass flux and concentration, and break-up of solids clusters. At ambient conditions, gas-solids mass transfer was investigated for cocurren...