نتایج جستجو برای: lateral dose

تعداد نتایج: 432495  

Purpose: To study the benefits of Directional Bremsstrahlung Splitting (DBS) dose variance reduction technique in BEAMnrc Monte Carlo (MC) code for Oncor® linac at 6MV and 18MV energies. Materials and Method: A MC model of Oncor® linac was built using BEAMnrc MC Code and verified by the measured data for 6MV and 18MV energies of various field sizes. Then Oncor® machine was modele...

ژورنال: سنجش و ایمنی پرتو 2020

Nowadays, in order to improve the accuracy of treatment in radiation therapy, there are many attempts to use magnetic resonance imaging (MRI) due to the advantages of excellent soft tissue contrast and ultra-fast pulse sequences. On the other hand, carbon-ion radiation therapy is developing rapidly due to the benefits of greater relative biological effectiveness (RBE) and the application in the...

Mansour Zabih Zade Marziyeh Tahmasbi Mohammad Javad Tahmasebi Birgani Nahid Chegeni

Introduction: Integrated radiation therapy - MRI systems are capable of delivering high doses to the target tissues near sensitive organs and achieve better therapeutic results; however, the Applied magnetic fields for imaging, can influence the charged path, change the penetration depth and deflect the particles, laterally, leading to dose distribution variations. Therefore, i...

Journal: :iranian journal of medical physics 0
nsikan u. esen - department of physics, akwa ibom state university, pmb 1167 uyo, nigeria

introduction radiation exposures from diagnostic medical examinations are generally low and are almost always justified by the benefits of accurate diagnosis of possible disease conditions. therefore, entrance skin dose (esd), body organ dose (bod), and effective dose (ed) from adult patients undergoing routine thorax posterior-anterior (pa) and thorax right lateral (rlat) were estimated in uni...

2012
Eric C. Schreiber Daren L. Sawkey Bruce A. Faddegon

The assumption of cylindrical symmetry in radiotherapy accelerator models can pose a challenge for precise Monte Carlo modeling. This assumption makes it difficult to account for measured asymmetries in clinical dose distributions. We have performed a sensitivity study examining the effect of varying symmetric and asymmetric beam and geometric parameters of a Monte Carlo model for a Siemens PRI...

2017
Yinghui Li Lixin Chen Jinhan Zhu Xiaowei Liu

PURPOSE The aim of this study was to combine a set of methods for use of radiochromic film dosimetry, including calibration, correction for lateral effects and a proposed triple-channel analysis. These methods can be applied to GAFCHROMIC EBT3 film dosimetry for radiation field analysis and verification of IMRT plans. METHODS A single-film exposure was used to achieve dose calibration, and th...

Nsikan U. Esen, Rachel. I. Obed

Introduction Radiation exposures from diagnostic medical examinations are generally low and are almost always justified by the benefits of accurate diagnosis of possible disease conditions. Therefore, entrance skin dose (ESD), body organ dose (BOD), and effective dose (ED) from adult patients undergoing routine thorax posterior-anterior (PA) and thorax right lateral (RLAT) were estimated in Uni...

2003
Dirk Focken

Hiermit erkläre ich, die vorliegende Arbeit selbständig erstellt und keine anderen als die angegebenen Quellen verwendet habe.

Journal: :Medical physics 1997
E Wong J Van Dyk Y Zhu

Previously published FFT dose calculations and their verifications have been performed for field sizes greater than 10 cm x 10 cm with photon energies up to 18 MV [Zhu and Boyer, Phys. Med. Biol. 35, 351-368 (1990)]. With a smaller field size at megavoltage energies, lateral electronic disequilibrium exists in low density inhomogeneities which is not handled properly by the FFT calculations. In...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی مشهد - دانشکده دندانپزشکی 1393

چکیده مقدمه: پیوند استخوان شکاف آلوئل ماگزیلا، یک عمل ظریف و حساس جهت جبران نقص (vip-ct) موجود بوده که یکی از عوامل مهم در موفقیت آن پوشش مناسب پیوند می باشد. فلپ روش جدیدی جهت vascularized interpositional periosteal- connective tissue بازسازی تک مرحله ای نقص های وسیع بافت نرم همزمان با پیوند استخوان می باشد. هدف از مطالعه برای پوشش lateral sliding و vip-ct حاضر مقایسه میزان موفقیت و عوارض...

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