abstract   background: the survival curves generally have been used for analysis of cell survival under stress conditions. they depict the relationship between the fraction of cells retaining their reproductive integrity and the absorbed dose. the median lethal dose, lethal concentration, 50% (lc 50 ) of a  toxin ,  radiation , or  pathogen  is the  dose required to kill half the members of a t...

The absorbed dose in vials containing photo-sensitizer solutions irradiated under neutron beams produced by the p-Li, D-D and D-T reactions was calculated. Monte Carlo simulations were performed coupling NeuSDesc MCNP codes order to derive energy spectrum, fluence with depth samples. estimated taking into account contributions of all particles (photons, electrons, protons alpha particles). This...

Introduction Radiotherapy is regarded as the first treatment of choice for nasopharyngeal carcinoma. Despite the advantages of radiotherapy, patients may suffer from a wide range of side-effects due to the presence of many sensitive normal tissues in these regions. If the absorbed dose exceeds the tolerance level in parotid glands and the spinal cord, myelopathy, Lhermitte's sign and xerostomia...

introduction: in this paper, by complete definition of human eye containing the various parts and their materials, the difference between this model and a homogeneous water phantom are compared for two ophthalmic plaques using 125i and 103pd. material and methods: the simulation of the two phantoms were performed in the mcnp-4c code and by using the geometry of a three-dimensional eye, differen...

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...

The dose calculation accuracy of a commercial pencil beam IMRT planning system is evaluated by comparison with Monte Carlo calculations and measurements in an anthropomorphic phantom. The target volume is in the right lung and mediastinum and thus significant tissue inhomogeneities are present. The Monte Carlo code is an adaptation of the MCNP code and the measurements were made with TLD and fi...

Introduction: In brachytherapy, radioactive sources are placed close to the tumor, therefore, small changes in their positions can cause large changes in the dose distribution. This emphasizes the need for computerized treatment planning. The usual method for treatment planning of cervix brachytherapy uses conventional radiographs in the Manchester system. Nowadays, because of their advantages ...