Introduction: The presence of heterogeneities such as air-filled cavities in the head and neck treatment fields region, may result in potential dosimetric disagreement because the losses of charged particle equilibrium. Most of treatments planning systems are not able to predict dose distribution of inhomogeneities region accurately. Therefore, dose calculation algorithms need to...

Background: Gel polymers are considered as new dosimeters for determining radiotherapy dose distribution in three dimensions.Objective: The ability of a new formulation of MAGIC-f polymer gel was assessed by experimental measurement and Monte Carlo (MC) method for studying the effect of gold nanoparticles (GNPs) in prostate dose distributions under the internal Ir-192 and external 18MV radiothe...

We examined the adequacy of existing shielding guidelines using five-year clinical data from a busy CyberKnife center. From June 2006 through July 2011, 1,370 patients were treated with a total of 4,900 fractions and 680,691 radiation beams using a G4 CyberKnife. Prescription dose and total monitor units (MU) were analyzed to estimate the shielding workload and modulation factor. In addition, b...

pinch technology is one of the best methods for designing a multi stream heat exchanger(mshe) through a network; current pinch-based methods, however, lead to a larger and more complicateddesign problems. the major drawback of the current methods is they result in designs having more individual mshe sections than essential, correspond to the enthalpy intervals on temperature vs. enthalpy diagra...

in this paper, we study spacelike dual biharmonic curves. we characterize spacelike dual biharmonic curves in terms of their curvature and torsion in the lorentzian dual heisenberg group . we give necessary and sufficient conditions for spacelike dual biharmonic curves in the lorentzian dual heisenberg group . therefore, we prove that all spacelike dual biharmonic curves are spacelike dual heli...

background: recent studies in eye plaque brachytherapy have shown a considerable difference between the dosimetric results using water phantom and a model of human eye containing realistic materials. in spite of this fact, there is a lack of simulation studies based on such a model in proton therapy literatures. in the presented work, the effect of utilizing an eye model with ocular media on pr...

Background: Inclusion of inhomogeneity corrections in intensity modulated small fields always makes conformal irradiation of lung tumor very complicated in accurate dose delivery.Objective: In the present study, the performance of five algorithms via Monte Carlo, Pencil Beam, Convolution, Fast Superposition and Superposition were evaluated in lung cancer Intensity Modulated Radiotherapy plannin...