Estimation of Core Temperature Elevation in Humans and Animals for Whole-Body Averaged Sar

Hirata, Akimasa; Sugiyama, Hironori; Fujiwara, Osamu

doi:10.2528/pier09101603

Cited by 48 publications

(27 citation statements)

References 24 publications

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“…The investigators found no measurable change in body temperature, despite the fact that the average whole-body SAR was 0.086 or 0.95 W/kg (depending on the pulse sequence used) and imaging times extended up to 90 min. They are also consistent with results of recent modelling studies that predict increases in core temperature of 0.1 -0.15 C in humans after 1 h of exposure in normal room environments to RF energy at a whole body average SAR of 0.4 W/kg (the basic restriction in the IEEE and ICNIRP standards for occupational exposure) [21]. The present writer also notes that these temperature increases are far smaller than would be predicted by extrapolating results from small-animal experiments, undoubtedly because the human body has a far more efficient thermoregulatory system than the rodents and other animals used for RF bioeffects studies [18].…”

Section: Thermoregulatory Effects Of Heatingsupporting

confidence: 79%

Thermal aspects of exposure to radiofrequency energy: Report of a workshop

Foster

Morrissey

2011

International Journal of Hyperthermia

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This special issue contains papers presented at an international workshop entitled 'Thermal Aspects of Radio Frequency Exposure' convened in Gaithersburg, Maryland, USA on 11-12 January 2010, and co-sponsored by the Mobile Manufacturers Forum, the GSM Association, and the US Food and Drug Administration. The goals of the workshop were to (1) identify appropriate health endpoints associated with thermal hazards and their time-dependence thresholds, and (2) outline future directions for research that might lead to an improved understanding of health and safety implications of human exposure to radiofrequency energy and design of improved exposure limits for this energy. This present contribution summarises some of the major conclusions of the speakers, and offers comments by one of the present authors on proposed research priorities and the implications of the material presented at the workshop for setting improved thermally based limits for human exposure to RF energy.

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Section: Thermoregulatory Effects Of Heatingsupporting

confidence: 79%

Thermal aspects of exposure to radiofrequency energy: Report of a workshop

Foster

Morrissey

2011

International Journal of Hyperthermia

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“…This field induces eddy-currents in his body. The problem of numerical evaluation of currents induced in the human body due to the external magnetic or electromagnetic fields was investigated, e.g., in papers [1][2][3][4][5][6][7], and also reported in previous works by the author [8,9].…”

Section: Introductionmentioning

confidence: 99%

Validation of a Numerical Approach to the Analysis of a Live-Line Worker Exposure to the Electric Field

Krajewski¹

2011

PIER

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Abstract-The aim of this paper is to validate a proposed simplified boundary-integral approach (that is called here LEM&BEM) for the analysis of electric field in a live-line-working zone. A human body model of a simplified geometry that is applied to the electric field estimation around the live-line worker is also tested. Numerical results of a more accurate numerical approach, laboratory measurements as well as results of measurements taken on a real tower of HV overhead line are employed for this purpose. The numerical analysis of the electric field distribution in the hot-stick working zone on an anchor tower of 400 kV transmission line is presented to demonstrate the effectiveness of the numerical technique under consideration. The author's own software packages has been applied in computations.

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“…The local temperature rise in the tissue surrounding the electrodes can reach very dangerous levels. The local nature of the dangerous effect means that a whole-body averaged SAR value, [12], will not be useful in determining the local effect: It is the local SAR distribution that is more important. Although the heating effect is primarily in the tissue near the electrodes, and the nature of this tissue is certainly important, yet the nature of the tissue in which the connecting portion of the lead is embedded and the length of the entire lead are also important.…”

Section: Introductionmentioning

confidence: 99%

Concentration of the Specific Absorption Rate Around Deep Brain Stimulation Electrodes During Mri

Mohsin

2011

PIER

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Abstract-During Magnetic Resonance Imaging (MRI), the presence of an implant such as a Deep Brain Stimulation (DBS) lead in a patient's body can pose a significant risk. This is due to the fact that the MR radiofrequency (RF) field can achieve a very high strength around the DBS electrodes. Thus the specific absorption rate (SAR), which is proportional to the square of the magnitude of the RF electric field, can have a very high concentration in the near-field region of the electrodes. The resulting tissue heating can reach dangerous levels. The degree of heating depends on the level of SAR concentration. The effects can be severe, leading to tissue ablation and brain damage, and significant safety concerns arise whenever a patient with an implanted DBS lead is exposed to MR scanning. In this paper, SAR, electric field, and temperature rise distributions have been found around actual DBS electrodes. The magnitude and spatial distribution of the induced temperature rises are found to be a function of the length and structure of the lead device, tissue properties and the MR stimulation parameters.

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Estimation of Core Temperature Elevation in Humans and Animals for Whole-Body Averaged Sar

Cited by 48 publications

References 24 publications

Thermal aspects of exposure to radiofrequency energy: Report of a workshop

Thermal aspects of exposure to radiofrequency energy: Report of a workshop

Validation of a Numerical Approach to the Analysis of a Live-Line Worker Exposure to the Electric Field

Concentration of the Specific Absorption Rate Around Deep Brain Stimulation Electrodes During Mri

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