Thermal Injury in Human Subjects Due to 94-GHz Radio Frequency Radiation Exposures

Parker, James E.; Eggers, Jeffrey S.; Tobin, Philip E

doi:10.21236/ada631765

Cited by 3 publications

(14 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present model, with no adjustment in thermal parameters, predicts temperature increases about 20% higher than observed in the Walters study [18] and roughly a factor of two above results of Parker et al [19]. The reason for the larger discrepancy with Parker's data [19] is unclear. However, in that study the beam diameter on the subject's back was small (3 cm in diameter) and the study used an indirect method of exposure assessment with uncertain accuracy.…”

Section: Comparison With Experimentscontrasting

confidence: 58%

“…The thermal model can be validated with reference to experiments by Walters et al [18]. (One of the present authors participated in the analysis in that study) together with data from a much smaller studies by Parker et al [19]. In [18], 10 subjects (7 males, 3 females) were exposed on their backs to 3-sec 94 GHz pulses with incident power densities ranging from 9-17.5 kW/m 2 , with simultaneously measurements of skin temperature using infrared thermography.…”

Section: Comparison With Experimentsmentioning

confidence: 90%

“…The model yields corresponding fluences of 92.5, 96 and 148 kJ/m for 3-sec pulses at 94 GHz. Parker et al [19] suggested somewhat higher thresholds, 120-180 kJ/m 2 for second-degree burns, although these estimates are based on very scant data. Fig.…”

Section: Burnsmentioning

confidence: 97%

“…7, with each datapoint representing a single exposure to a single subject. Subsequently, Parker et al [19] exposed 6 subjects once each to their lower backs/buttocks to 3-sec pulses of RF energy at 94 GHz at a higher incident power density (40 -60 kW/m 2 ) with subsequent medical examination for skin damage. Measured temperature increases from that study are also shown in Fig.…”

Section: Comparison With Experimentsmentioning

confidence: 99%

“…Measured vs. calculated transient increases of skin temperature in backs of subjects exposed to 3-sec pulses of 94 GHz mm-waves, with an approximate fluence of 45 J/m 2 . () 226 separate exposures to 12 subjects[18], (n) 6 exposures to 2 subjects[19].…”

mentioning

confidence: 99%

See 4 more Smart Citations

Transient Thermal Responses of Skin to Pulsed Millimeter Waves

et al. 2020

View full text Add to dashboard Cite

This study examines thermal responses of skin to pulsed millimeter wave (mm-wave) radiofrequency (RF) radiation. We review limits for pulse fluence in the IEEE Std. C95.1-2019 and the 2020 guideline of the International Commission on Nonionizing Radiation Protection (ICNIRP), as well as the recently reaffirmed guidelines of the U.S. Federal Communications Commission (FCC). The study employs a simple one-dimensional thermal model for skin and Pennes' bioheat equation (BHTE). The predicted temperature increases produced by 3-sec pulses at 94 GHz agree well with previous experimental results with no adjustable parameters in the model, and the anticipated threshold of cutaneous thermal pain and burns are consistent with the scant available data for pulsed mm-waves, as well as a larger body of data on thermal hazards from pulsed infrared radiation. The model suggests that the implicit limits on pulse fluence in present FCC guidelines might allow, in extreme (and, in practice, unrealistic) cases, transient increases in skin temperature that can approach thresholds for thermal pain but well below those anticipated to cause thermal damage. Limits on pulse fluence in the current IEEE and ICNIRP exposure guidelines would preclude such effects. For realistic exposures from wireless and other technologies that transmit pulsed RF energy that comply with time-averaged exposure limits, the pulse fluence is far too low to produce hazardous thermal transients in skin. A thermal analysis of FCC's proposed "device-based time averaging" shows that the resulting limits on device emissions will result in thermal transients in skin that are roughly an order of magnitude below much slower increases in temperature due to time-averaged exposure. An appendix discusses the applicability of two approximations to the bioheat equation that can be used to estimate temperature increases in skin from exposure to mm-waves.

show abstract

Section: Comparison With Experimentscontrasting

confidence: 58%

Section: Comparison With Experimentsmentioning

confidence: 90%

Section: Burnsmentioning

confidence: 97%

Section: Comparison With Experimentsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Transient Thermal Responses of Skin to Pulsed Millimeter Waves

et al. 2020

View full text Add to dashboard Cite

show abstract

Human exposure to radiofrequency energy above 6 GHz: review of computational dosimetry studies

et al. 2021

View full text Add to dashboard Cite

International guidelines/standards for human protection from electromagnetic fields have been revised recently, especially for frequencies above 6 GHz where new wireless communication systems have been deployed. Above this frequency a new physical quantity 'absorbed/epithelial power density' has been adopted as a dose metric. Then, the permissible level of external field strength/power density is derived for practical assessment. In addition, a new physical quantity, fluence or absorbed energy density, is introduced for protection from brief pulses (especially for shorter than 10 s). These limits were explicitly designed to avoid excessive increases in tissue temperature, based on electromagnetic and thermal modeling studies but supported by experimental data where available. This paper reviews the studies on the computational modeling/dosimetry which are related to the revision of the guidelines/standards. The comparisons with experimental data as well as an analytic solution are also been presented. Future research needs and additional comments on the revision will also be mentioned.

show abstract

Time-temperature Thresholds and Safety Factors for Thermal Hazards from Radiofrequency Energy above 6 GHz

2021

View full text Add to dashboard Cite

Two major sets of exposure limits for radiofrequency (RF) radiation, those of the International Commission on Nonionizing Radiation Protection (ICNIRP 2020) and the Institute of Electrical and Electronics Engineers (IEEE C95.1–2019), have recently been revised and updated with significant changes in limits above 6 GHz through the millimeter wave (mm-wave) band (30–300 GHz). This review compares available data on thermal damage and pain from exposure to RF energy above 6 GHz with corresponding data from infrared energy and other heat sources and estimates safety factors that are incorporated in the IEEE and ICNIRP RF exposure limits. The benchmarks for damage are the same as used in ICNIRP IR limits: minimal epithelial damage to cornea and first-degree burn (erythema in skin observable within 48 h after exposure). The data suggest that limiting thermal hazard to skin is cutaneous pain for exposure durations less than ≈20 min and thermal damage for longer exposures. Limitations on available data and thermal models are noted. However, data on RF and IR thermal damage and pain thresholds show that exposures far above current ICNIRP and IEEE limits would be required to produce thermally hazardous effects. This review focuses exclusively on thermal hazards from RF exposures above 6 GHz to skin and the cornea, which are the most exposed tissues in the considered frequency range.

show abstract

Thermal Injury in Human Subjects Due to 94-GHz Radio Frequency Radiation Exposures

Cited by 3 publications

References 2 publications

Transient Thermal Responses of Skin to Pulsed Millimeter Waves

Transient Thermal Responses of Skin to Pulsed Millimeter Waves

Human exposure to radiofrequency energy above 6 GHz: review of computational dosimetry studies

Time-temperature Thresholds and Safety Factors for Thermal Hazards from Radiofrequency Energy above 6 GHz

Contact Info

Product

Resources

About