Abstract
The potential for excessive radiofrequency (RF) exposure is generally greatest in the near-field of RF sources. Present-day RF exposure standards are primarily derived from dosimetry associated with uniform exposure of the entire body. This is particularly true for the limits on spatial peak specific absorption rate (SAR). Normally, however, the very intense and localized RF fields to which some personnel are exposed are clearly not uniform over the body and this raises the question of the appropriateness of partial-body relaxation provisions in various exposure standards. SAR measurement data obtained during the course of evaluating the effectiveness of RF protective clothing have demonstrated the existence of localized SARs that can substantially exceed recommended limits (e.g., 8 W/kg in any one gram of tissue), even though the local RF field incident on the body does not exceed maximum permissible exposure (MPE) limits for partial body exposures. These data indicate that body curvature plays a significant role in determining the peak SAR and may be most important for the head. The findings also suggest that the field polarization and source position relative to the body are critical determinants of the maximum, local SAR value. These results point to the need for a better understanding of how localized SAR is related to conditions of exposure and challenge the validity of peak SAR limits that are based on the assumption of uniform exposure.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
IEEE (1991) IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz IEEE C95.1–1991, Institute of Electrical and Electronics Engineers, 345 East 47th Street, New York, NY 10017.
Guy, A. W., Webb, M. D., and Sorensen, C. C. (1976) Determination of power absorption in man exposed to high frequency electromagnetic fields by thermographie measurements on scale models, IEEE Transactions on Biomedical Engineering BME-23, 361–370.
Tell, R. A. (1997) SAR Evaluation of the Naptex TM Suit for Use in the VHF and UHF Telecommunications Bands. Technical report prepared for Motorola by Richard Tell Associates, Inc., 8309 Garnet Canyon Lane, Las Vegas, NV 89129.
Adair, E. R., Kelleher, S. A., Mack, G. W., and Morocco, T. S. (1998) Thermophysiological responses of human volunteers during controlled whole-body radio frequency exposure at 450 MHz, Bioelectromagnetics 19, 232–245.
Kuster, N. and Tell, R. A. (1989) A dosimetric assessment of the significance of high intensity RF field exposure resulting from reradiating structures. Paper D-1–5 presented at the Eleventh Annual Meeting of the Bioelectromagnetics Society, Tucson, AZ, June 18–22, p. 24 (book of abstracts).
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2000 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Tell, R.A. (2000). Evaluating Partial-Body Radiofrequency Field Exposures: The Need for Better Near-field Dosimetry. In: Klauenberg, B.J., Miklavčič, D. (eds) Radio Frequency Radiation Dosimetry and Its Relationship to the Biological Effects of Electromagnetic Fields. NATO Science Series, vol 82. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-4191-8_35
Download citation
DOI: https://doi.org/10.1007/978-94-011-4191-8_35
Publisher Name: Springer, Dordrecht
Print ISBN: 978-0-7923-6405-4
Online ISBN: 978-94-011-4191-8
eBook Packages: Springer Book Archive