for superficial lesions, the electrons may be used for radiation therapy. the high energy photons and electrons are produced by a linear accelerator (linac).   many of electron fields need the shielding of normal or critical organs. the electron shields are usually lead slabs with few millimeter thickness which should be placed near the skin, less than 1 centimeter away from skin. in the inspec...

introduction after the publication of task group number 43 dose calculation formalism by the american association of physicists in medicine (aapm), this method has been known as the most common dose calculation method in brachytherapy treatment planning. in this formalism, the water phantom is introduced as the reference dosimetry phantom, while the attenuation coefficient of the sources in the...

Introduction: Monte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The purpose of this research is comparison between 6 MV Primus LINAC simulation output with commissioning data using EGSnrc and build a Monte Carlo geometry of 6 MV Primus LINAC as realistically as possible. The BEAMnrc and DOSXYZnrc (EGSnrc package) M...

PURPOSE The aim of this in-vitro investigation was to describe the effect of reinforcement with different fibers on impact strength of heat polymerized polymethyl methacrylate (PMMA) denture base resin and to analyze the effect of surface treatment of the fibers on the impact strength. MATERIALS AND METHODS The specimens were fabricated from the dies formed as per standard ASTM D4812. 2% by w...

this paper investigates the radiative absorptivity of a spherical cavity by using monte carlo techniques. several parameters such as the angle of incoming radiation which inters the cavity for both diffuse wall cavity and specular wall cavity has been  investigated. the absorptivity of a spherical cavity has been calculated and compared with the exact values when the angle of incoming radiation...

Background: Palladium-103 (103Pd) is a brachytherapy source for cancer treatment. The Monte Carlo codes are usually applied for dose distribution and effect of shieldings. Monte Carlo calculation of dose distribution in water phantom due to a MED3633 103Pd source is presented in this work. Materials and Methods: The dose distribution around the 103Pd Model MED3633 located in the center of 30×...

abstract background: accurate methods of radiation therapy dose calculation. there are different monte carlo codesfor simulation of photons, electrons and the coupled transport of electrons and photons. mcnpis a general purpose monte carlo code that can be used for electron, photon and coupledphoton-electron transport.monte carlo simulation of radiation transport is considered to be one of the ...

the determination of gyration radius is a strong research for configuration of a macromolecule. italso reflects molecular compactness shape. in this work, to characterize the behavior of theprotein, we observe quantities such as the radius of gyration and the average energy. we studiedthe changes of these factors as a function of temperature for acetylcholine receptor protein in gasphase with n...

Monte Carlo simulations are typically characterized by a large number of unknown parameters, many of which are difficult to obtain experimentally. Parameter sensitivity analysis can be used to quantify the effect of the unknown parameters. This information can be used to decide which parameters should be optimized or determined more accurately through further experimental or simulation studies....