علی اصغر مولوی
استاد گروه فیزیک، دانشگاه حکیم سبزواری، سبزوار
[ 1 ] - مقایسه تاثیر دو ترکیب هدف- فیلتر مختلف در میزان دوز جذبی پستان در ماموگرافی و بررسی عوامل موثر بر آن به کمک کد MCNPX
ماموگرافی با اشعه x یکی از روش‌های پر‌کاربرد در تشخیص سرطان پستان می‌باشد. به دلیل حساسیت بافت پستان، میزان دُز دریافتی بیمار در ماموگرافی اهمیت ویژه‌ای دارد. هدف از مطالعه حاضر، بررسی عوامل موثر در میزان دُز جذبی و مقایسه میزان دُز دریافتی برای شرایطی که دستگاه ماموگرافی شامل ترکیب هدف-فیلتر Mo-Moیا W-Rh باشد. در این پژوهش، به کمک کد MCNPX، ساختار تیوپ اشعه x دستگاه ماموگرافی شبیه سازی شده و طیف...
[ 2 ] - اندازه‌گیری گاز رادون و تورون در مجاور گسل های فعال شمال شرق ایران
Radon and Thoron are the radioisotopes which radiate high alpha energy particles. These two gases can enter in the body by different ways such as inhalation, eating and drinking and then destroy body`s internal tissues and cause the lung cancer. The condensation of these gases differs in various areas and is more in zones near active faults. In this research, first the relation of Radon and Tho...
[ 3 ] - Calculation of beta absorbed fractions for iodine isotopes in ellipsoidal thyroid lobe
Background: The thyroid gland absorbs nearly all the iodine in the blood, independently of its isotopic composition. When a large enough activity of radioactive iodine like 131I, 132I, 133I is taken into the body, it can destroy the healthy thyroid gland cells as well as the cancer’s cells. In fact, as it is well known, some isotopes of iodine are used not only for acquiring thyroid image...
[ 4 ] - Treatment couch positioning uncertainties using an EPID-based method
Introduction: The accuracy of patient positioning plays an important role for radiotherapy tasks. Short and automated Quality Assurance (QA) programs are becoming one of the challenging tasks in Radiotherapy. The current study, investigates the accuracy of treatment couch positioning with four degrees of freedom (4DoF) using a fast and accurate method based on an image acquired...
[ 5 ] - Assessment of secondary neutron dose due to dental restorations in head and neck radiation therapy
Introduction: One of scientific concern is increasing of unwanted neutron dose to the patient, in head and neck radiation therapy due to the presence of some isotopes in dental restorations and head of medical linac. The aim of this study is to measure the equivalent dose of thermal and fast neutron due to head of Siemens Primus Linac and a healthy tooth, Amalgam, Ni-Cr alloy a...
[ 6 ] - Evaluating the doismetric characteristics of some beta- emitter radionuclides for skin lesions irradiation
Introduction: The dosimetric characteristics of patch sources including 32P, 90Y, 188Re and 166Ho, which are employed for radionuclide skin therapy, have been evaluated in current study Materials and Methods: The patch sources understudy were modeled by MCNPX Monte Carlo code and corresponding depth dose distribution, transverse dose profile and isodose curves...
[ 7 ] - Impact of Various Beam Parameters on Lateral Scattering in Proton and Carbon-ion Therapy
Background: In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness.Methods: In this study, we used Monte Carlo method-based Geant4 toolkit to s...
[ 8 ] - Absorbed Dose Assessment from Short-Lived Radionuclides of Radon (222Rn) Decay Chain in Lung Tissue: A Monte Carlo Study
Introduction: Internal exposure to radon gas progeny can lead to serious biologic damages to the lung tissue. The aim of this study was to evaluate the absorbed dose by lung tissue due to the exposure from short-lived radioactive products of radon (222Rn) decay using Monte Carlo simulation. Material and Methods: A lung equivalent p...
[ 9 ] - A new model for Spread Out Bragg Peak in proton therapy of uveal melanoma
In this research, in order to improve our calculations in treatment planning for proton radiotherapy of ocular melanoma, we improved our human eye phantom planning system in GEANT4 toolkit. Different analytical models have investigated the creating of Spread Out Bragg Peak (SOBP) in the tumor area. Bortfeld’s model is one of the most important analytical methods. Using convolution method, a new...
[ 10 ] - Using PSO algorithm optimization for planning 103Pd seeds brachytherapy positions
Radiation therapy, is one of the treatments for cancer. Brachytherapy is a radiotherapeutic technique that a sealed radiation source is placed inside or next to the tissue and has become a mainstream treatment option for cancer. Achieving maximum dose to the gland as well as minimum injury to the adjacent tissues is a basic principle in radiation therapy. Sources configuration must be designed ...
[ 11 ] - Evaluation of the relative biological effectiveness of the Auger electrons produced during gadolinium neutron capture therapy using microdosimetric approach
Determination of the relative biological effectiveness (RBE) of Auger electrons is a challenging task in radiobiology. In this study, we have estimated the RBE of internal conversion (IC) and Auger electrons released during Gadolinium neutron capture reaction (GNCR) by means of biological weighting functions (BWFs) with microdosimetric approach. Regarding the different distribution of Gadoliniu...
[ 12 ] - Effect of concentration of QDs Cadmium Sulfide in Study of Optical Properties under Gamma Irradiation in Order to use in dosimetry
In this work, for the first time, effect of gamma irradiation on the optical properties of CdS (quantum dots) QDs in various concentrations was studied. The aqueous CdS QDs were synthesized in a facile and fast method by using domestic microwave oven. Three concentration of QDs; 20, 2, 0.4 mg/cc after different administrated dose of gamma irradiation (0-20 kGy) were studied. The results showed...
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