نتایج جستجو برای: specific absorption rate sar

تعداد نتایج: 2034338  

Journal: :Bioelectromagnetics 2008
Nadia Falzone Carin Huyser Francois Fourie Tim Toivo Dariusz Leszczynski Daniel Franken

Ejaculated, density purified, human spermatozoa were exposed to pulsed 900 MHz GSM mobile phone radiation at two specific absorption rate levels (SAR 2.0 and 5.7 W/kg) and compared with controls over time. Change in sperm mitochondrial membrane potential was analysed using flow cytometry. Sperm motility was determined by computer assisted sperm analysis (CASA). There was no effect of pulsed 900...

2004
J. R. Trevithick M. O. Creighton M. Sanwal

Damage to rat lenses in vitro caused by continuous (CW) and 24 kWpk microwave pulsed (PW) wave radiation fits a model correlating damage to specific absorption (SA), a product of the specific absorption rate (SAR) and exposure time. This model was extended to include new exposure conditions: higher peak powers of PW radiation at additional pulse durations. The overall model related damage to th...

Journal: :Biomedizinische Technik. Biomedical engineering 2016
Minmin Luo Can Hu Yayun Zhuang Wufan Chen Feng Liu Sherman Xuegang Xin

The specific absorption rate (SAR) is an important issue to be considered in fetus MRI at 3 T due to the high radiofrequency energy deposited inside the body of pregnant woman. The high dielectric material (HDM) has shown its potential for enhancing B1 field and reducing SAR in MRI. The aim of this study is to assess the feasibility of SAR reduction by adding an HDM to the fetus MRI. The feasib...

Journal: :Physics in medicine and biology 2010
J W Hand Y Li J V Hajnal

Numerical simulations of specific absorption rate (SAR) and temperature changes in a 26-week pregnant woman model within typical birdcage body coils as used in 1.5 T and 3 T MRI scanners are described. Spatial distributions of SAR and the resulting spatial and temporal changes in temperature are determined using a finite difference time domain method and a finite difference bio-heat transfer so...

Journal: :Magnetic resonance in medicine 2015
Ingmar Graesslin Peter Vernickel Peter Börnert Kay Nehrke Giel Mens Paul Harvey Ulrich Katscher

PURPOSE The goal of this study is to increase patient safety in parallel transmission (pTx) MRI systems. A major concern in these systems is radiofrequency-induced tissue heating, which can be avoided by specific absorption rate (SAR) prediction and SAR monitoring before and during the scan. METHODS In this novel comprehensive safety concept, the SAR is predicted prior to the scan based on pr...

Journal: :Journal of magnetic resonance imaging : JMRI 2008
Adam C Zelinski Leonardo M Angelone Vivek K Goyal Giorgio Bonmassar Elfar Adalsteinsson Lawrence L Wald

PURPOSE To investigate the behavior of whole-head and local specific absorption rate (SAR) as a function of trajectory acceleration factor and target excitation pattern due to the parallel transmission (pTX) of spatially tailored excitations at 7T. MATERIALS AND METHODS Finite-difference time domain (FDTD) simulations in a multitissue head model were used to obtain B(1) (+) and electric field...

Journal: :Balkan journal of electrical & computer engineering 2021

A dual-band wearable antenna is designed on a textile material. The design operates at ISM bands available for Wireless Body Area Network and Local with an input match better than -15 dB. by using Computational Electromagnetic Software (CEMS) based finite-difference time-domain (FDTD) method. three-layer phantom model including skin, fat muscle has been considered to compute the specific absorp...

2004
Mark S. Mirotznik Erik Cheever Kenneth R. Foster

We describe a thermistor-based technique for measurement of the specific absorption rate (SAR) of radio frequency energy from a small antenna in lossy matter with high spatial resolution. The apparatus employs a small thermistor probe, that is moved about the antenna using a computer-controlled positioning system. The antenna is excited by pulses of radio frequency energy, and the SAR is obtain...

Journal: :Bioelectromagnetics 1995
H Lai N P Singh

Levels of DNA single-strand break were assayed in brain cells from rats acutely exposed to low-intensity 2450 MHz microwaves using an alkaline microgel electrophoresis method. Immediately after 2 h of exposure to pulsed (2 microseconds width, 500 pulses/s) microwaves, no significant effect was observed, whereas a dose rate-dependent [0.6 and 1.2 W/kg whole body specific absorption rate (SAR)] i...

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