| Description |
This thesis was performed in response to the growing interest in the health effects of human exposure to radiofrequency (RF) and microwave (MW) electromagnetic (EM) radiation. The characteristics and effects of RF and MW radiation are similar in some ways and different in other ways than other forms of EM radiation, such as light, infrared, and x-rays. The similarities and differences of these forms of radiation are discussed. The biological effects of RF and MW radiation have be studied for years: at first primarily in animal experiments and accidental human exposure, and more recently in more diverse and sophisticated studies. Because of the growing scientific interest and information in this area, the recent studies of RF and MW human effects have become more sophisticated and include computerized mathematical human geometric model studies; studies on subtle biologic effects, such as changes in electroencephalograms, lymphocytes, etc, ; human mannequin studies; epidemiological studies; etc. Many of these studies of RF and MW exposure effects have been used to determine and set safe human industrial exposure standards. Because of the increase of knowledge on this subject, the human exposure standards for RF and MW have changed considerable in the past 10 to 20 years. In the past, the RF and MW standards have been based upon electrical energy exposure determined at the skin surface as a power density. Much of the recent research on human RF and MW exposure has been used to determine the actual electrical energy absorption within the body. More recent studies on geometric models and mannequins have been done to determine the actual and body-area-specific electrical energy absorption, expressed as specific absorption rates (SAR). By determining the SAR in various body areas, organs, and tissues, more specific electrical energy absorption can be determined for safer exposure standards. In this study, measurement of electrical energy were made inside a human cadaver while it was exposed to specific RF irradiation (27.12 MHz) of an industrial dielectric heat sealer. Determination of the internal electrical energy absorption was made in various body areas and these values compared to a specific geometric human model study. The electric fields (E and E2) were determined for all test areas and a statistical analysis and comparison was made between many body areas. Comparative E2 values and SAR values were calculated for areas of statistically significant difference. A comparison of the ratio of SAR values in certain, selected areas of this study was made to similar areas in a geometric human model study. The results of this study showed a remarkable correlation of specific electrical energy absorption within the human cadaver as compared to the computerized human geometric model study. Electrical energy (E2) and energy absorption (SAR) were determined in even more specific body areas than in the computerized human model studies and effects of various tissues and organs were studied. SAR values in specific body areas found to be in an expected range and compatible with recommended RF exposure standards. |
