نتایج جستجو برای: absorbed dose
تعداد نتایج: 326013 فیلتر نتایج به سال:
in order to improve the performance of a newly developed radiochromic film, gic-79, somedosimetric characteristics of this film have been studied based on relevant standard practice. the presentstudy describes some parameters that may affect the dosimeter response before, during, and after irradiation. the effect of absorbed dose rate on dosimeter response was determined by irradiating dosimete...
Background: Monte Carlo method (MC) has played an important role in design and optimization of medical linacs head and beam modeling. The purpose of this study was to compare photon beam features of two commercial linacs, Varian 21EX and Elekta SL-25 using MCNP4C MC code. Materials and Methods: The 6MV photon beams of Varian 21EX and Elekta Sl-25 linacs were simulated based on manufacturers pro...
Introduction: Today electrophysiology studies and ablation have been developed due to increasing arrhythmias disorder of heart. In these diagnostic – treatments methods, the use of fluoroscopy can be causes patient radiation dose, therefore evaluation of patient's absorbed dose is necessary to protection of the radiation. The aim of this study was to evaluate the absorbed dose in patients under...
Introduction: Quality assurance in Computed tomography (CT) centers in developing countries are largely hindered by the unavailability of CT phantoms. The development of a local CT phantom for the measurement of organ radiation absorbed dose is therefore requisite. Material and Methods: Local CT phantoms were designed to meet the standard criteria of 32 cm diameter for body, 16 cm diameter for...
During radiotherapy by any radiation, it is always essential to stop absorbing the excess dose by a tissue. To better treat cancerous tissues and to make more precise irradiation for a cancerous tumor, there needs the accurate irradiation time to be estimated. First, the constituent materials of any of the existing organs in abdominal tissue are extracted and defined in the MCNPX code. Then, ev...
Introduction: Nuclear medicine techniques have been widely employed in the assessment of gastroesophageal dysfunction. Gastroesophageal reflux (GER) is a common, self-limited process in infants and children that usually resolves at 12 to 18 months of age. Clinical management of GER includes conservative treatment, thickened feedings, positional therapy and parental reassurance. On the other han...
BACKGROUND Radiotherapy plays an important role in the management of most malignant and many benign primary central nervous system (CNS) tumors. Radiotherapy affects both tumor cells and uninvolved normal cells; so, it is important to estimate absorbed dose to organs at risk in this kind of treatment. The aim of this study was to determine the absorbed dose to chiasma, lens, optic nerve, retina...
Introduction Radon is a colorless and tasteless gas which exists in most soils. It is a substance that poses a potential risk for lung cancer in case a person is exposed to high levels over long periods of time. The Environmental Protection Agency (EPA) estimates that 90% of lung cancers per year are caused by radon. The aim of this paper is to estimate the absorbed doses of 222Rn by MCNPX simu...
Background: Radioiodine therapy has proven to be an effective method in the treatment of patients with differentiated thyroid carcinoma after thyroidectomy. The scope of this study is to describe a method to obtain the dose of organs using medical internal radiation dosimetry (MIRD) method. At the end, the results of MIRD calculations were compared with thermoluminescent dosimeter (TLD...
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