Background: The presence of a wedge filter in the beam trajectory can modify the beam quality and cause some changes in the dosimetry parameters which are usually difficult to be measured directly and accurately. Material and Methods: In this study the MCNP-4C Monte Carlo code was used to simulate the 9 MV photon beam generated by a linear accelerator. Upon getting a good agreement bet...

introduction: in recent decades, several monte carlo codes have been introduced for research and medical applications. these methods provide both accurate and detailed calculation of particle transport from linear accelerators. the main drawback of monte carlo techniques is the extremely long computing time that is required in order to obtain a dose distribution with good statistical accuracy. ...

background: the aim of this work was to establish how well gel dosimeters performed, as substitutes for brain tissue compared with standard phantom materials such as water, polymethyl-methacrylate (or pmma), a150 plastic and te- liquid phantom material for dosimetry of neutron beams in boron neutron capture therapy. materials and methods: thermal neutron fluence, photon dose and epithermal neut...

conclusion by comparing the results, we saw that w/rh anode/filter combination is the best choice in breast mammography imaging because of the lowest delivered dose in comparison with w/ag and rh/al. moreover, breast thickness and g value have significant effects on mgd. objectives the aim of this study was to determine the average absorbed dose of x-ray radiation in the glandular tissue of the...

background: in this work investigation of the normoxic pagat polymer gel dosimeter such as sensitivity, the r2-dose response with post time and the percentage depth dose (pdd) of pagat polymer gel dosimeter have been undertaken. materials and methods: using mri, the formulation to give the maximum change in the transverse relaxation rate r2 was determined to be 4.5% n,n'-methylenbis- acryl...

the monte carlo method can be used to describe any technique that approximates solutions to quantitative problems through statistical sampling. this method is considered to be the most accurate method for dose calculation in radiotherapy. for complete modeling of a linear accelerator, it is required that the manufactured information covers all data, but some data such as primary electron energy...

MCNP is widely used Monte Carlo program in reactor and nuclear physics. However, an option of simulating electrons was added into the code a few years ago. With this extension MCNP became a code, potentially applicable for applications in medical physics. In 1997, a new version of the code, named MCNP4B was released, which contains several improvements in electron transport modelling. To test s...

background: skin cancer can be treated by various methods. electron radiotherapy has been a useful therapeutic modality in the treatment of skin cancers in areas which are difficult to cure by other methods. depth dose distribution of 166ho using varskin2 code is presented in this work. material and methods: depth dose distribution of 166ho was calculated, using varskin2 code by adding of 166ho...

INTRODUCTION Monte Carlo (MC) methods have become the "gold standard" for assessing dose distribution, organ doses and effective dose associated with the exposure, both external and internal, of humans to ionizing radiation. Powerful and sophisticated tools for simulation of radiation transport (for example, MCNP, EGS4) are now widely available. However, these codes are designed for general-pur...

Monte Carlo calculations are frequently used to analyse a variety of radiological science applications using low-energy (10-1000 keV) photon sources. This study seeks to create a low-energy benchmark for the MCNP Monte Carlo code by simulating the absolute dose rate in water and the air-kerma rate for monoenergetic point sources with energies between 10 keV and 1 MeV. The analysis compares four...