Empirical and theoretical dosimetry in support of whole body resonant RF exposure (100 MHz) in human volunteers.
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 degrees 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.
Allen
Stewart J
SJ
Veridian Engineering, Brooks City Base, Texas 78235, USA. stewart.allen@brooks.af.mil
Adair
Eleanor R
ER
Mylacraine
Kevin S
KS
Hurt
William
W
Ziriax
John
J
D000328:Adult; D003198:Computer Simulation; D006801:Humans; D008297:Male; D008954:Models, Biological; D011829:Radiation Dosage; D011846:Radio Waves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014915:Whole-Body Counting / Q000295:instrumentation* / Q000379:methods*; D014916:Whole-Body Irradiation / Q000379:methods*