نتایج جستجو برای: icru
تعداد نتایج: 261 فیلتر نتایج به سال:
زمینه و هدف: مهمترین کمیت فیزیکی تابش برای پیشگویی و ارزیابی پاسخ نمونه های بیولوژیکی به پرتوگیری، دوز جذبی است. براساس گزارش های icru(international commission on radiation units and measurements)، تعیین دوز جذبی پرتوها در سالهای اخیر در محدوده 5/3%، توصیه و تنظیم می شود. معمولاً توزیع دوز در ماده هموژن با دانسیته واحد تخمین زده می شود؛ در حالی که حجم مورد تابش متشکل از لایه های مختلفی از چربی، ...
Background: Toxicity assessment is done by comparing HDR brachytherapy with ICRU point doses. D2cc doses of OAR in slightly more than Objectives:The primary objective volumetric dose and toxicity comparison between brachytherapy. Materials Methods: It a prospective comparative study. The total number patients enrolled the study 20. After obtaining informed consent, then were All diagnosed H.P.E...
In this work, conversion coefficients for the operational quantity H'(3;Ω) have been calculated for both mono-energetic photons from 2 keV to 50 MeV for angles of incidence from 0° up to 180° in steps of 15° (to complement ICRU 57) as well as for photon reference radiation qualities (to complement ISO 4037). Finally, parameters necessary to determine the influence of the air density on the conv...
The development of dosimetric concepts and the definition of specific quantities for use in radiation protection has a long history. An important basis for the present concepts was already provided in the 60’s and 70’s by both the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU). In 1991 in its Publication 60 ...
Background: Present study compares two high-dose-rate intracavitary brachytherapy (ICBT) planning methods using two-dimensional orthogonal radiography and three-dimensional computed tomography (3D-CT) with regard to dose target volume organs at risk (OAR) in carcinoma cervix. Methodology: ICBT plans for 22-patients were compared 2D techniques. treatment generated 2D-orthogonal images was prescr...
The objective of the study is to investigate the propagation of Ca(2+) waves in full-width cardiac myocytes and carry out sensitivity analysis to study the effects of various physiological parameters on global Ca(2+) waves. Based on the anomalous subdiffusion of Ca(2+) sparks, a mathematical model was proposed to characterize the Ca(2+) waves. The computed results were in agreement with the exp...
Response of a micro volume (0.01 ml) ionization chamber has been studied with pulsed proton beams which are used for clinical purposes and has been compared with those of some JARP ionization chambers (0.6 ml). All chambers used had been calibrated by standard 60Co beams at the Electrotechnical Laboratory (ETL) and exposure calibration factors, Nx, were obtained on advance. Two methods are used...
INTRODUCTION Brachytherapy is an integral part in the treatment of cervical uteri cancer patients. Orthogonal treatment planning is the standard mode of calculation based on reference points. Introduction of the innovative 3-D computer based treatment planning allows accurate calculation based on volumetric information as regards the target volume and organs at risk (OAR). Also provide dose vol...
BACKGROUND AND PURPOSE Conformal radiotherapy requires accurate dose calculation at the dose specification point, at other points in the planning target volume (PTV) and in organs at risk. To assess the limitations of treatment planning of lung tumours, errors in dose values, calculated by some simple tissue inhomogeneity correction algorithms available in a number of currently applied treatmen...
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