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Numerical study of RF exposure and the resulting temperature rise in the foetus during a magnetic resonance procedure
- Source :
- Physics in Medicine and Biology. 55:913-930
- Publication Year :
- 2010
- Publisher :
- IOP Publishing, 2010.
-
Abstract
- 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 solver that accounts for discrete vessels. Heat transfer from foetus to placenta via the umbilical vein and arteries as well as that across the foetal skin/amniotic fluid/uterine wall boundaries is modelled. Results suggest that for procedures compliant with IEC normal mode conditions (maternal whole-body averaged SAR(MWB)or = 2 W kg(-1) (continuous or time-averaged over 6 min)), whole foetal SAR, local foetal SAR(10 g) and average foetal temperature are within international safety limits. For continuous RF exposure at SAR(MWB) = 2 W kg(-1) over periods of 7.5 min or longer, a maximum local foetal temperature38 degrees C may occur. However, assessment of the risk posed by such maximum temperatures predicted in a static model is difficult because of frequent foetal movement. Results also confirm that when SAR(MWB) = 2 W kg(-1), some local SAR(10g) values in the mother's trunk and extremities exceed recommended limits.
- Subjects :
- medicine.medical_specialty
Time Factors
Amniotic fluid
Materials science
Radio Waves
Rf exposure
Movement
Mothers
Models, Biological
Fetus
Pregnancy
Normal mode
medicine
Humans
Computer Simulation
Radiology, Nuclear Medicine and imaging
Radiation
Radiological and Ultrasound Technology
medicine.diagnostic_test
Temperature
Finite difference
Specific absorption rate
Magnetic resonance imaging
Mechanics
Magnetic Resonance Imaging
Surgery
Heat transfer
Female
Subjects
Details
- ISSN :
- 13616560 and 00319155
- Volume :
- 55
- Database :
- OpenAIRE
- Journal :
- Physics in Medicine and Biology
- Accession number :
- edsair.doi.dedup.....01ef37e9b864344f2a2f71a9d3e22d93
- Full Text :
- https://doi.org/10.1088/0031-9155/55/4/001