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Empirical and theoretical dosimetry in support of whole body resonant RF exposure (100 MHz) in human volunteers
Author(s) -
Allen Stewart J.,
Adair Eleanor R.,
Mylacraine Kevin S.,
Hurt William,
Ziriax John
Publication year - 2003
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.10129
Subject(s) - dosimetry , specific absorption rate , bioelectromagnetics , anechoic chamber , imaging phantom , finite difference time domain method , dipole antenna , dipole , optics , antenna (radio) , physics , electromagnetic field , acoustics , nuclear medicine , computer science , telecommunications , medicine , quantum mechanics
This study reports the dosimetry performed to support an experiment that measured physiological responses of volunteer human subjects exposed to the resonant frequency for a seated human adult at 100 MHz. Exposures were performed in an anechoic chamber which was designed to provide uniform fields for frequencies of 100 MHz or greater. A half wave dipole with a 90° reflector was used to optimize the field at the subject location. The dosimetry plan required measurement of transmitter harmonics, stationary probe drift, field strengths as a function of distance, electric and magnetic field maps at 200, 225, and 250 cm from the dipole antenna, and specific absorption rate (SAR) measurements using a human phantom, as well as theoretical predictions of SAR with the finite difference time domain (FDTD) method. On each exposure test day, a measurement was taken at 225 cm on the beam centerline with a NBS E field probe to assure consistently precise exposures. A NBS 10 cm loop antenna was positioned 150 cm to the right, 100 cm above, and 60 cm behind the subject and was read at 5 min intervals during all RF exposures. These dosimetry measurements assured accurate and consistent exposures. FDTD calculations were used to determine SAR distribution in a seated human subject. This study reports the necessary dosimetry for work on physiological consequences of human volunteer exposures to 100 MHz. Bioelectromagnetics 24:502–509, 2003. Published 2003 Wiley‐Liss, Inc.