نتایج جستجو برای: dose rate and radiation source
تعداد نتایج: 17000624 فیلتر نتایج به سال:
Background: HDR brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. In this method, depending on how advanced one tumor is, 2 to 6 Gy dose as intracavitary brachytherapy is prescribed. Due to high dose rate and tumor location, accuracy evaluation of treatment planning system (TPS) is particularly important. Common methods used in TPS dosimetry are based on computat...
background: hdr brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. in this method, depending on how advanced one tumor is, 2 to 6 gy dose as intracavitary brachytherapy is prescribed. due to high dose rate and tumor location, accuracy evaluation of treatment planning system (tps) is particularly important. common methods used in tps dosimetry are based on computat...
background: monte carlo and experimental relative dose determination in a water phantom, due to a high dose rate (hdr) 192ir source is presented for real energy spectrum and monochromatic at 356 kev. materials and methods: the dose distribution has been calculated around the 192ir located in the center of 30 cm ×30 cm ×30 cm water phantom using mcnp4c code by monte carlo method. relative dose v...
Introduction In order to discharge the patients receiving treatment with large radiation doses of 131I for thyroid cancer, it is necessary to measure and evaluate the external dose rates of these patients. The aim of the study was to assess a new method of external dose rate measurement, and to analyze the obtained results as a function of time. Materials and Methods In this study, a telescopic...
background : limited studies are available on the calculation of radiation exposure and its associated risks for people in contact with patients who have been treated with permanent prostate brachytherapy. in this study the changes in the radiation exposure were calculated in different stages of the bladder fullness in prostate seed brachytherapy. methods :magnetic resonance images of three pat...
Introduction: One of the protective concepts in the interpretation of radiation damage in radiobiology is the radioadaptive response. The objective of this present report is to evaluate the induction of radioadaptive response in male rats by injection of pre-irradiated serum with low doses X-radiation intraperitoneally. Materials and Methods: 80 male adul...
Introduction: Megavoltage X-ray beams are used to treat cervix cancer due to their skin-sparing effect. Preferably, the radiation surface doses should be negligible; however, it increases due to electron contamination produced by various field parameters. Therefore, it is essential to provide proper knowledge about the effect of different field parameters on radiation doses. This study sought t...
Abstract Background: Follicles are part of epidermis and pass through a cell cycle. The result of this cell division is producing hair. Follicles specially growing follicles are very sensitive against irradiation and are damaged by low dose rates. So in this study investigated the relationship between chronic exposure of radiation workers and their hair loss. Materials and methods: In this stud...
The high-energy UV ray radiation on PIN Silicon photodiodes reduces the optimal parameters of these photodiodes. In this paper, by representing a model, we compare the effect of UV dose on the bright current in these two types of photodiodes and confirm the analytic relationships in order to simulate a model with the help of the Silvaco- Atlas software. In this model, Silicon photodiodes and Ga...
The first quality assurance process for validating dose-volume histogram data involving brachytherapy procedures in radiation therapy is presented. The process is demonstrated using both low dose-rate and high dose-rate radionuclide sources. A rectangular cuboid was contoured in five commercially available brachytherapy treatment planning systems. A single radioactive source commissioned for QA...
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