نتایج جستجو برای: کد geant4

تعداد نتایج: 7627  

مقدمه: افزایش دز بافت های سرطانی و حفاظت از بافت های سالم یکی از مهم ترین چالش ها در رادیوتراپی می باشد. نشاندار کردن تومور با عناصر سنگین(با عدد جرمی بالا) در روش درمانی فعال سازی فوتونی(Photon Activation Therapy) می تواند دز ناحیه تومور را به صورت گزینشی نسبت به بافت های سالم مجاور افزایش دهد. در این تحقیق، اثر پارامترهای مختلف نظیر انرژی پرتوهای ایکس، نوع و غلظت عوامل فعال ساز، در توزیع دز ب...

2002
Maurício Moralles Carla da Costa Guimarães Emico Okuno

The employment of Monte Carlo simulations in the applied nuclear physics techniques has increased with the data processing capabilities of the commercial personal computers. Since the inclusion of the low-energy electromagnetic interactions in GEANT4, this Monte Carlo simulation toolkit has produced results which reveal its promising utilization in radiation dosimetry, radiation protection and ...

2011
Olga Yevseyeva Joaquim T. de Assis Ivan Evseev Hugo R. Schelin Sergei A. Paschuk João A. P. Setti Katherin S. Díaz Joel M. Hormaza Ricardo T. Lopes

Proton beams in medical applications deal with relatively thick targets like the human head or trunk. Thus, the fidelity of proton computed tomography (pCT) simulations as a tool for proton therapy planning depends in the general case on the accuracy of results obtained for the proton interaction with thick absorbers. GEANT4 simulations of proton energy spectra after passing thick absorbers do ...

2016
Elliott Leonard Jacob Leonard Susan Halbig

Typically water is used as an analog material for Deoxyribonucleic Acid (DNA) in Monte Carlo simulations of biological radiation interactions. Prior to this work, it was unclear whether water is an appropriate stand-in for DNA when simulating direct radiation damage on the nano scale. The increased interest in targeted tumor therapy using Auger electrons has requires an understand of the radiob...

الهام نیا, مهسا, حسن طلب, محمد, صادقی, مهدی, قاسمی, محمدرضا,

زمینه و هدف: به منظور افزایش دز جذبی در ناحیه تومور، از روش فعال سازی فوتونی، با نشاندار کردن تومور به وسیله عناصر فعال‌ساز سنگین نظیر Gd و تابش‌دهی آن با پرتوهای ایکس اورتو ولتاژ، استفاده می شود. در این روش، اثر فوتوالکتریک در ناحیه تومور غالب بوده که موجب افزایش دز موضعی خواهد شد. مواد و روش کار: در مدل طراحی شده بر اساس کد کامپیوتریGeant4 به منظور بررسی توزیع دز در نواحی مختلف بافت سالم و تو...

2005
S. Paganini E. Vilela

Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the male adult voxels phantom MAX, developed in the Nuclear Ene...

2017
Mansour Almurayshid Yusuf Helo Andrzej Kacperek Jennifer Griffiths Jem Hebden Adam Gibson

PURPOSE In this article, we evaluate a plastic scintillation detector system for quality assurance in proton therapy using a BC-408 plastic scintillator, a commercial camera, and a computer. METHODS The basic characteristics of the system were assessed in a series of proton irradiations. The reproducibility and response to changes of dose, dose-rate, and proton energy were determined. Photogr...

2010
Xin Dong Gene Cooperman John Apostolakis

This work presents an application case study. Geant4 is a 750,000 line toolkit first designed in the mid-1990s and originally intended only for sequential computation. Intel’s promise of an 80-core CPU meant that Geant4 users would have to struggle in the future with 80 processes on one CPU chip, each one having a gigabyte memory footprint. Thread parallelism would be desirable. A semiautomatic...

Journal: :Physics in medicine and biology 2004
D Lazaro I Buvat G Loudos D Strul G Santin N Giokaris D Donnarieix L Maigne V Spanoudaki S Styliaris S Staelens V Breton

Monte Carlo simulations are increasingly used in scintigraphic imaging to model imaging systems and to develop and assess tomographic reconstruction algorithms and correction methods for improved image quantitation. GATE (GEANT4 application for tomographic emission) is a new Monte Carlo simulation platform based on GEANT4 dedicated to nuclear imaging applications. This paper describes the GATE ...

Journal: :Physics in medicine and biology 2015
C Fedon F Longo G Mettivier R Longo

Mean glandular dose (MGD) is the main dosimetric quantity in mammography. MGD evaluation is obtained by multiplying the entrance skin air kerma (ESAK) by normalized glandular dose (DgN) coefficients. While ESAK is an empirical quantity, DgN coefficients can only be estimated with Monte Carlo (MC) methods. Thus, a MC parameters benchmark is needed for effectively evaluating DgN coefficients. GEA...

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