SAR distribution in human beings when using body-worn RF transmitters

This study analyzes the exposure of the human torso to electromagnetic fields caused by wireless body-mounted or handheld devices. Because of the frequency and distance ranges from 30-5800 MHz and 10 to 200 mm, respectively, both near-field and far-field effects are considered. A generic body model and simulations of anatomical models are used to evaluate the worst case tissue composition with respect to the absorption of electromagnetic energy. Both standing wave effects and enhanced coupling of reactive near-field components can lead to a specific absorption rate (SAR) increase in comparison to homogeneous tissue. In addition, the exposure and temperature increase of different inner organs is assessed. With respect to compliance testing, the observed SAR enhancement may require the introduction of a multiplication factor for the spatial peak SAR measured in the liquid-filled phantom in order to obtain a conservative exposure assessment. The observed tissue heating at the body surface under adiabatic conditions can be significant, whereas the temperature increase in the inner organs turned out to be negligible for the cases investigate

Transtelephonic Electrocardiographic Transmission in the Preparticipation Screening of Athletes

Transtelephonic electrocardiographic transmission (TET) is the most widespread form of telecardiology since it enables clinicians to assess patients at a distance. The purpose of this study was to assess the efficacy and effectiveness of TET either by fixed telephone line (POTS) or by mobile phone in the preparticipation screening of young athletes. A total of 506 players, aged 20.5 ± 6.2 years, from 23 soccer clubs in the prefecture of Thessaloniki, Greece, were physically examined in their playfields by a general practitioner (GP) and had their ECG recorded. In 142 cases, and on the judgment of the GP, the ECG was transmitted via POTS and/or global system for mobile communications (GSM) to a specialised medical centre where it was evaluated by a cardiologist. The mean total time for recording, storing, and transmitting the ECG was four minutes per subject. It was found that the success rate for transmission at first attempt was similar for both fixed and mobile networks, that is, 93% and 91%, respectively. The failure rate in the GSM network was correlated to the reception level at the site of transmission. Only in about half (n = 74) of the transmitted ECGs did the cardiologist confirm “abnormal” findings, although in 16, they were considered to be clinically insignificant. Consequently, 58 athletes were referred for further medical examination. Our results indicate that TET (either by fixed telephone line or by mobile phone) can ensure valid, reliable, and objective measurements, and significantly contribute to the application of medical screening in a great number of athletes. Therefore, it is recommended as an alternative diagnostic tool for the preparticipation screening of athletes living in remote areas

Fast assessment of RF power absorption in indoor environments by room electromagnetics theory

A fast method to assess radiofrequency (RF) radiation absorption in humans present in realistic indoor environments is proposed. The only required inputs are the room characteristics and the weight and position of the human with respect to the electromagnetic source. The method is compared and validated with full finite-difference time-domain simulations. Various realistic scenarios are investigated, in which one to six human phantoms are present. Whole-body power absorption ranges from 23.5 to 85.9 mu W kg(-1) with a median deviation of similar to 3.1 dB (51 %). While this difference may appear large, it is outbalanced by a calculation time of less than a second for the proposed method compared with similar to 17.5 h for a single full-wave electromagnetic simulation

A validated methodological approach to prove the safety of clinical electromagnetic induction systems in magnetic hyperthermia

The present study focuses on the development of a methodology for evaluating the safety of MNH systems, through the numerical prediction of the induced temperature rise in superficial skin layers due to eddy currents heating under an alternating magnetic field (AMF). The methodology is supported and validated through experimental measurements of the AMF’s distribution, as well as temperature data from the torsos of six patients who participated in a clinical trial study. The simulations involved a computational model of the actual coil, a computational model of the cooling system used for the cooling of the patients during treatment, and a detailed human anatomical model from the Virtual Population family. The numerical predictions exhibit strong agreement with the experimental measurements, and the deviations are below the estimated combined uncertainties, confirming the accuracy of computational modeling. This study highlights the crucial role of simulations for translational medicine and paves the way for personalized treatment planning.peer-reviewe