Exposure of non‐target tissues in medical diathermy

Leitgeb, Norbert; Omerspahic, Alecko; Niedermayr, Florian

doi:10.1002/bem.20521

Cited by 18 publications

(12 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The accuracy of the electromagnetic solver was set to -30 dB, which is adequate as shown by recent studies [31,35] . The system of thermal equations has been solved with a numerical accuracy of 10 -12 for the stationary thermal simulations and 10 -9 for the thermal transient solver.…”

Section: Numerical Simulationmentioning

confidence: 99%

Simulation of the temperature elevation in children exposed to plane wave electromagnetic fields (10 MHz–1 GHz) at the ICNIRP reference level

Niedermayr

Leitgeb

Siegl

2012

Biomedizinische Technik/Biomedical Engineering

View full text Add to dashboard Cite

Because of a lack of thermal models, to date, limitation of exposure to an electromagnetic field (EMF) has been based on restricting intracorporal specific absorption rates. To allow convenient compliance checks, reference field values have been defined. If they are met, compliance with basic restrictions is assumed. This article demonstrates that this assumption is not valid in every case. It has therefore been investigated as to whether the biological goal of limiting tissue heating is still met, in particular with regard to children. The thermal solver applied is based on the bioheat equation, with implemented additional improvements that allow consideration of blood flow and metabolic rate as a function of local tissue temperature rise and, in addition, adapt the blood temperature relative to the absorbed power. As a further improvement, heat exchange at the tissue/air boundary has been modeled, with radiation, convection, and sweating considered as well. The mathematical equations describing these additional thermoregulatory mechanisms were taken from the literature and unified in the thermoregulatory model used for this study. For the investigated case of plane wave exposure, the results confirm the violation of the basic restrictions in five of the six models when exposed to reference EMF levels. However, using thermal modeling, it was possible to demonstrate that heating remained within the biological tolerances. In particular, temperature elevation of the body core temperature remained <0.014°C and the local peak temperature did not exceed 1°C.

show abstract

Section: Numerical Simulationmentioning

confidence: 99%

Simulation of the temperature elevation in children exposed to plane wave electromagnetic fields (10 MHz–1 GHz) at the ICNIRP reference level

Niedermayr

Leitgeb

Siegl

2012

Biomedizinische Technik/Biomedical Engineering

View full text Add to dashboard Cite

show abstract

“…The applied numerical anatomical human model NORMAN is already well established and commonly used for investigations, although in another field, namely to assess potential health risks from exposure to electromagnetic fields [25,40]. It has the advantage to represent the average European man.…”

Section: Discussionmentioning

confidence: 99%

Cardiac fibrillation risk of TASER X-26 dart mode application

Leitgeb

Niedermayr

Loos

et al. 2011

Wien Med Wochenschr

View full text Add to dashboard Cite

In view of reported fatalities there are still controversial discussions on whether electronic stun law enforcement weapons can cause cardiac fibrillation. Experimental data are contradictory. Simplified theoretical estimations led to a negligible low risk of 8.10(-7). With a detailed numerical-anatomical model of an adult man (NORMAN) cardiac exposure to Taser X26 high-tension pulses was quantitatively assessed and the fibrillation risk estimated by accounting for its dependence on excited volume based on 3D cardiac exposure patterns. For distance mode and worst case dart hits it could be demonstrated that cardiac exposure can reach the 30% fibrillation risk level. Risk reduces considerably if direct current flow across the heart is prevented. The overall fibrillation risk of Taser application is further reduced by the limited probability of critical hits. However, in agreement with experimental findings it is demonstrated that cardiac fibrillation risk of Taser X26 dart mode application is small, however, not negligible.

show abstract

“…The use of the numerical anatomical model of a slim man is already widely accepted and validated for investigations of different kind of electric and electromagnetic interference [8,12,14]. It could be expected that CED application at larger and/or more obese persons would lead to lower interference voltages.…”

Section: Discussionmentioning

confidence: 99%

Risk of Pacemaker Patients by TASER X26 Contact Mode Application

Leitgeb¹,

Niedermayr²,

Neubauer³

et al. 2012

JEMAA

View full text Add to dashboard Cite

The prevalence of pacemaker patients among the general population and of conducted energy devices (CED) for law enforcement and self-defence is increasing. Consequently, the question whether cardiac pacemaker (CPM) patients are on particular risk becomes increasingly important. The risk of Taser X26 electric interference with implanted CPM has been investigated by numerical simulation at MRI-based anatomical models of CPM patients with devices implanted at conventional sites (left pectoral, right pectoral and abdominal) and with the monopolar CPM electrode placed at the ventricular apex. In spite of 10 fold higher peak voltages the different coupling conditions make Taser-induced CPM interference voltages lower than those caused by external cardiac defibrillators. It is shown that electric interference considerably depends on ECD electrode orientation. The most unfavourable conditions are encountered with ECD electrodes aligned with the line from the CPM electrode tip to CPM can (EPC line). It could be shown that worst case interference voltages of monopolar pacemakers of any kind of implantation remain below the pulse immunity level as defined in safety standards of implantable cardiac pacemakers and of cardioverter defibrillators. However, interference voltages exceed CPM sensing thresholds. Therefore, capturing should be expected at Taser X26 contact mode application at any position at the upper part of the body including the abdomen, both at frontal and dorsal positions.

show abstract

Exposure of non‐target tissues in medical diathermy

Cited by 18 publications

References 22 publications

Simulation of the temperature elevation in children exposed to plane wave electromagnetic fields (10 MHz–1 GHz) at the ICNIRP reference level

Simulation of the temperature elevation in children exposed to plane wave electromagnetic fields (10 MHz–1 GHz) at the ICNIRP reference level

Cardiac fibrillation risk of TASER X-26 dart mode application

Risk of Pacemaker Patients by TASER X26 Contact Mode Application

Contact Info

Product

Resources

About