نتایج جستجو برای: dose rate constant
تعداد نتایج: 1402387 فیلتر نتایج به سال:
Introduction: Brachytherapy is the use of small encapsulated radioactive sources in close vicinity of tumors. Various methods are used to obtain the dose distribution around brachytherapy sources. TG-43 is a dosimetry protocol proposed by the AAPM for determining dose distributions around brachytherapy sources. The goal of this study is to update this protocol for presence of bone and air inhom...
Introduction Low dose rate brachytherapy sources have been widely used for interstitial implants in tumor sites, particularly in prostate. Dosimetric characteristics of a new IrSeed 125I brachytherapy source have been determined using the LiF thermoluminescent dosimeter (TLD) chips. Materials and Methods Dose rate constant, radial dose function, and anisotropy function around the IrSeed 125I so...
Variable dose rate single-arc IMAT delivered with a constant dose rate and variable angular spacing.
Single-arc intensity-modulated arc therapy (IMAT) has gained worldwide interest in both research and clinical implementation due to its superior plan quality and delivery efficiency. Single-arc IMAT techniques such as the Varian RapidArc deliver conformal dose distributions to the target in one single gantry rotation, resulting in a delivery time in the order of 2 min. The segments in these tec...
Radioactive 125I and 192Ir seeds are widely used as sources for interstitial implantation.192Ir is one of the important sources frequently used in brachytherapy. Up to now, different commercial models of this source type have been introduced to the clinical radiation oncology applications. The aim of the present study is to determine the dosimetric parameters of this new PDR Ir-192 source model...
a lithium borate thermoluminescence dosimeter with 0.3 wt% of manganese impurityconcentration was prepared for high dose levels in the range of 1-30 kgy for gamma irradiation applications.the tld reader was used for read out purposes from ambient temperature to about 400°c with a heating rate of 6°c/sec. the pre- and post- irradiation anneal temperature was 300°c for 1.5 and 1 hours respectivel...
براکی تراپی، روشی در پرتو درمانی است که در آن از چشمه های رادیواکتیو ویژه ای در فاصله ی نزدیک، در تماس یا کاشت در تومور، برای درمان استفاده می شود به طوری که بافت آسیب دیده بیشترین دز را دریافت کرده در حالی که به بافت های سالم اطراف آن آسیب کمتری برسد. چشمه ها ی 103pd و 125i به طور گسترده در درمان تومورهای بدخیم استفاده می شوند. در سال 1986 چشمه 103pdبه عنوان یک انتخاب مناسب برای جایگزینی چشم...
background: iodine brachytherapy sources with low photon energies have been widely used in treating cancerous tumors. dosimetric parameters of brachytherapy sources should be determined according to aapm tg-43u1 recommendations before clinical use. monte carlo codes are reliable tools in calculation of these parameters for brachytherapy sources. materials and methods: dosimetric parameters (dos...
introduction: brachytherapy is the use of small encapsulated radioactive sources in close vicinity of tumors. various methods are used to obtain the dose distribution around brachytherapy sources. tg-43 is a dosimetry protocol proposed by the aapm for determining dose distributions around brachytherapy sources. the goal of this study is to update this protocol for presence of bone and air inhom...
background: ionizing radiation is present in all environment of the earth’s surface, beneath the earth and in the atmosphere. human beings are exposed to external radiation from their surroundings naturally and also to internal radiation from food, water and air they consume. then, it is important to measure and develop knowledge about radiation. objective: this study is designed to evaluate th...
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