In vivo radiofrequency heating in swine in a 3T (123.2-MHz) birdcage whole body coil.
Magn Reson Med
; 72(4): 1141-50, 2014 Oct.
Article
em En
| MEDLINE
| ID: mdl-24259413
ABSTRACT
PURPOSE:
To study in vivo radiofrequency (RF) heating produced due to power deposition from a 3T (Larmour frequency = 123.2 MHz), birdcage, whole body coil.METHODS:
The RF heating was simulated in a digital swine by solving the mechanistic generic bioheat transfer model (GBHTM) and the conventional, empirical Pennes bioheat transfer equation for two cases 1) when the swine head was in the isocenter and 2) when the swine trunk was in the isocenter. The simulation results were validated by making direct fluoroptic temperature measurements in the skin, brain, simulated hot regions, and rectum of 10 swine (case 1 n = 5, mean animal weight = 84.03 ± 6.85 kg, whole body average SAR = 2.65 ± 0.22 W/kg; case 2 n = 5, mean animal weight = 81.59 ± 6.23 kg, whole body average SAR = 2.77 ± 0.26 W/kg) during 1 h of exposure to a turbo spin echo sequence.RESULTS:
The GBHTM simulated the RF heating more accurately compared with the Pennes equation. In vivo temperatures exceeded safe temperature thresholds with allowable SAR exposures. Hot regions may be produced deep inside the body, away from the skin.CONCLUSION:
SAR exposures that produce safe temperature thresholds need reinvestigation.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Temperatura Corporal
/
Imageamento por Ressonância Magnética
/
Irradiação Corporal Total
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Imagem Corporal Total
/
Calefação
/
Modelos Biológicos
Limite:
Animals
Idioma:
En
Revista:
Magn Reson Med
Assunto da revista:
DIAGNOSTICO POR IMAGEM
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos