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Purpose There is increasing use of open-bore vertical MR systems that consist of two planar RF coils. A recent study showed that the RF-induced heating of a neuromodulation device was much lower in the open-bore system at the brain and the chest imaging landmarks. This study focused on the hip and knee implants and compared the specific absorption rate (SAR) distribution in human models in a 1.2T open-bore coil with that of a 1.5T conventional birdcage coil. Methods Computational modeling results were compared against the measurement values using a saline phantom. The differences in RF exposure were examined between a 1.2T open-bore coil and a 1.5T conventional birdcage coil using SAR in an anatomical human model. Results Modeling setups were validated. The body placed closed to the coil elements led to high SAR values in the birdcage system compared with the open-bore system. Conclusion Our computational modeling showed that the 1.2T planar system demonstrated a lower intensity of SAR distribution adjacent to hip and knee implants compared with the 1.5T conventional birdcage system.

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.

This study addressed an important but not yet thoroughly investigated topic regarding human exposure to radio-frequency electromagnetic fields (RF-EMF) generated by vehicular connectivity. In particular, the study assessed, by means of computational dosimetry, the RF-EMF exposure in road users near a car equipped with vehicle-to-vehicle (V2V) communication antennas. The exposure scenario consisted of a 3D numerical model of a car with two V2V antennas, each fed with 1 W, operating at 5.9 GHz and an adult human model to simulate the road user near the car. The RF-EMF dose absorbed by the human model was calculated as the specific absorption rate (SAR), that is, the RF-EMF power absorbed per unit of mass. The highest SAR was observed in the skin of the head (34.7 mW/kg) and in the eyes (15 mW/kg); the SAR at the torso (including the genitals) and limbs was negligible or much lower than in the head and eyes. The SAR over the whole body was 0.19 mW/kg. The SAR was always well below the limits of human exposure in the 100 kHz–6 GHz band established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The proposed approach can be generalized to assess RF-EMF exposure in different conditions by varying the montage/number of V2V antennas and considering human models of different ages.

A real-time RF exposure setup for studying the mechanism of RF biological effects based on microelectrode array (MEA) is proposed in this letter. The reflection simulation and measurement of the exposure setup show that the exposure setup has a wide working bandwidth in the frequency range of dc-3.0 GHz. The specific adsorption rate (SAR) measurement and simulation results at some frequencies show that the SAR distributions in the electrode region are relatively uniform. The test of the real-time effects on neuron activities at the SAR of 2.2 W/kg with a continuous 2.45-GHz RF signal injection was carried out. The results show that most of the electrodes can work normally and will not be affected by electromagnetic field noise. Additionally, the setup is compact and the system with MEA platform is almost covered by metal, which would significantly improve the ability to isolate the internal and external electromagnetic waves.

The purpose of this paper is to present a fast method to predict the radio frequency (RF) exposure for multi-configuration implantable devices in the magnetic resonance imaging (MRI) environment by using an artificial neural network (ANN). A synthesizing framework is developed to improve the ANN, of which the inputs are the geometric dimensions of the targeted device and the output is the peak 1-g average SAR (SAR1g) of the device. The synthesizing framework integrates feature selection and performance optimization techniques, achieved by using the mean impact value (MIV) algorithm and genetic algorithm (GA), to identify the most impactful features and improve the performance of the ANN. The framework was implemented and validated with the samples of 576 implantable plate devices with various geometric dimensions. The dimensions of the device were determined by six parameters and the peak SAR1g of the devices was numerically calculated by using a full-wave electromagnetic solver based on the finite-difference time-domain method. The efficiency and accuracy of the proposed framework were systematically evaluated. Comparing with the unimproved ANN, the mean square error (MSE) of the predicted peak SAR1g decreased by 28.06% for the ANN using MIV algorithm, while the MSE decreased by 55.29% for the presented synthesizing framework. The MSE of the predicted peak SAR1g was 8.16 W2/kg2 and the correlation between the predicted and calculated peak SAR1g was 0.994 for the improved ANN in the studied cases.

Recently, interest in the effects of radio frequency (RF) on biological systems has increased and is partially due to the advancements and increased implementations of RF into technology. As research in this area has progressed, the reliability and reproducibility of the experiments has not crossed multidisciplinary boundaries. Therefore, as researchers, it is imperative to understand the various exposure systems available as well as the aspects, both electromagnetic and biological, needed to produce a sound exposure experiment. This systematic review examines common RF exposure methods for both in vitro and in vivo studies. For in vitro studies, possible biological limitations are emphasized. The validity of the examined methods, for both in vitro and in vivo , are analyzed by considering the advantages and disadvantages of each. This review offers guidance for researchers to assist in the development of an RF exposure experiment that crosses current multidisciplinary boundaries.

BackgroundThe use of electromagnetic (EM) technologies for military applications is gaining increasing interest to satisfy different operational needs, such as improving battlefield communications or jamming counterpart's signals. This is achieved by the use of high-power EM waves in several frequency bands (e.g., HF, VHF, and UHF). When considering military vehicles, several antennas are present in close proximity to the crew personnel, which are thus potentially exposed to high EM fields.MethodsA typical exposure scenario was reproduced numerically to evaluate the EM exposure of the human body in the presence of an HF vehicular antenna (2–30 MHz). The antenna was modeled as a monopole connected to a 3D polygonal structure representing the vehicle. Both the EM field levels in the absence and in the presence of the human body and also the specific absorption rate (SAR) values were calculated. The presence of the operator, partially standing outside the vehicle, was simulated with the virtual human body model Duke (Virtual Population, V.3). Several exposure scenarios were considered. The presence of a protective helmet was modeled as well.ResultsIn the area usually occupied by the personnel, E-field intensity radiated by the antenna can reach values above the limits settled by international safety guidelines. Nevertheless, local SAR values induced inside the human body reached a maximum value of 14 mW/kg, leading to whole-body averaged and 10-g averaged SAR values well below the corresponding limits.ConclusionA complex and realistic near-field exposure scenario of the crew of a military vehicle was simulated. The obtained E-field values radiated in the free space by a HF vehicular antenna may reach values above the safety guidelines reference levels. Such values are not necessarily meaningful for the exposed subject. Indeed, SAR and E-field values induced inside the body remain well below safety limits.

Citing support from the U.S. Food and Drug Administration's Center for Devices and Radiological Health, the U.S. Federal Communications Commission (FCC) announced in December 2019 that it reaffirms the RF radiation exposure li mits it first adopted in 1996 fa The action was undertaken in the face of appeals from some to tighten, and others to loosen, the existing limits. In the process, the FCC also resolved and terminated a 2013 Notice of Inquiry that sought public input on whether it should modify its existing RF exposure rules considering recent scientific opinions and authoritative expert views, among other issues [2]. Apparently, six years since the Notice of Inquiry, the FCC deems it appropriate to maintain the existing RF exposure limits. It is interesting to observe that the FCC dedined to make changes that would stiffen the current rules or to make any changes that would effectively relax the current rules.

Recently, there has been quite a bit of discussion about the safety of newer 5G wireless communication systems [1]. It is not uncommon to find articles that compare RF safety standards developed by different organizations and accept the validity of each without comment [2] or dismiss the validity of a given standard by claiming a conflict of interest [3]. Given this, it is reasonable to ask about the legitimacy of the standards setting process. In regulating human RF exposure, most countries in the world refer to standards generated by either the International Committee on Electromagnetic Safety (IEEE/ICES) and its Committee on Man and Radiation (COMAR) or the International Commission on Nonionizing Radiation (ICNIRP). Hence, it is reasonable to discuss the processes by which these bodies arrive at their standards or guidelines for human exposure to RF electromagnetic fields. That is the purpose of this document. Prior to equating the validity of any alternative standard to those of COMAR or ICNIRP, a similar analysis of the alternative should be done. One example of such an analysis is presented in [4].

The radio wave effect on biological tissues is of great interest to dermatologists, cosmetologists, and plastic surgeons. The modern information about radio wave therapy of involutional changes of face and neck skin is shown. A literature review of the physical aspects of the high-frequency current of the radio wave range is presented. The thermal and oscillation effects of radio frequency (RF) on biological tissues are shown, the mechanism of these effects at the cellular level is described. Primary targets of high-frequency currents exposure in the skin, their effect on the physicochemical properties of collagen and unicellular organisms are described. The mechanism of pulsed and continuous radio wave technologies and the possibility of their use in medical practice are described. Types of minimally invasive and non-invasive electrodes, when the choice of electrode diameter determines the therapy of specific clinical cases, are shown. The multifunctional minimally invasive RF device Innofill with needle and cannula active electrodes is presented. The technical characteristics and exposure modes of the device are considered. The features of the cannula electrode and the possibilities of its use in solving various dermatological and cosmetic problems are highlighted. A histological study of a combined technique of the Innofill radio wave method with the filler based on hyaluronic acid, was performed. A change in the amount of collagen and elastin fibers was noted. The distribution of the filler in the tissues was evaluated after the injection of the filler based on hyaluronic acid, after 30 and 60 seconds of RF exposure and after 30 seconds of RF exposure in a tunnel technique with the formation of a collagen channel. Histological material was stained with hematoxylin-eosin, Masson and Van Gieson trichrome. High efficiency, safety and prolonged effect of this exposure were described.

Background The ubiquitous diffusion of radiofrequency (RF) radiation across human living environments has attracted the attention of scientists. Though the adverse health effects of RF exposure remain debatable, it has been reported that the interaction of such radiation with biological macromolecular structures can be deleterious for stem cells, inducing impairment of their main functions involving self-renewal and differentiation. Purpose The purpose of this study was to determine whether exposure to RF of 169 megahertz (MHz) that is part of very high radiofrequency (VHF) range 30-300 MHz, could cause damage to stem cells by inducing senescence and loss of regenerative and DNA repair capacity. Methods The study was conducted on mesenchymal stromal cells (MSCs) containing a subpopulation of stem cells. The MSCs were exposed to RFs of 169 MHz administered via an open meter 2G "Smart Meter" for different durations of time. Result We did not observe modifications in MSC biology as a result of the RF exposure conducted in our experiments. Conclusion We concluded that MSCs are insensitive to RF radiation exposure at 169 MHz for various time intervals, including longer durations.

This paper presents Specific Absorption Rate (SAR) calculations by electromagnetic simulations (EM). A worst-case analysis is proposed to evaluate the compliance of Wireless Power Chargers (WPC) installed within a vehicle with the existing recommendations of exposure levels to Electro Magnetic Fields (EMF). This analysis is intended for low power wireless chargers (up to 15 W) operating at 127 kHz but the method could be extended to any kind of wireless power chargers. In addition, this method could be retained for assessing RF exposure compliance during the radio homologation process.

A set of three apparatus enabling RF exposure of aerosolized pathogens at four chosen frequencies (2.8 GHz, 4.0 GHz, 5.6 GHz, and 7.5 GHz) has been designed, simulated, fabricated, and tested. Each apparatus was intended to operate at high power without leakage of RF into the local environment and to be compact enough to fit within biocontainment enclosures required for elevated biosafety levels. Predictions for the range of RF electric field exposure, represented by the complex electric field vector magnitude, that an aerosol stream would be expected to encounter while passing through the apparatus are calculated for each of the chosen operating frequencies.

BACKGROUND: Little is known about radiofrequency electromagnetic fields (RF) from mobile technology and resulting dose in young people. We describe modeled integrated RF dose in European children and adolescents combining own mobile device use and surrounding sources. METHODS: Using an integrated RF model, we estimated the daily RF dose in the brain (whole-brain, cerebellum, frontal lobe, midbrain, occipital lobe, parietal lobe, temporal lobes) and the whole-body in 8358 children (ages 8-12) and adolescents (ages 14-18) from the Netherlands, Spain, and Switzerland during 2012-2016. The integrated model estimated RF dose from near-field sources (digital enhanced communication technology (DECT) phone, mobile phone, tablet, and laptop) and far-field sources (mobile phone base stations via 3D-radiowave modeling or RF measurements). RESULTS: Adolescents were more frequent mobile phone users and experienced higher modeled RF doses in the whole-brain (median 330.4 mJ/kg/day) compared to children (median 81.8 mJ/kg/day). Children spent more time using tablets or laptops compared to adolescents, resulting in higher RF doses in the whole-body (median whole-body dose of 81.8 mJ/kg/day) compared to adolescents (41.9 mJ/kg/day). Among brain regions, temporal lobes received the highest RF dose (medians of 274.9 and 1786.5 mJ/kg/day in children and adolescents, respectively) followed by the frontal lobe. In most children and adolescents, calling on 2G networks was the main contributor to RF dose in the whole-brain (medians of 31.1 and 273.7 mJ/kg/day, respectively). CONCLUSION: This first large study of RF dose to the brain and body of children and adolescents shows that mobile phone calls on 2G networks are the main determinants of brain dose, especially in temporal and frontal lobes, whereas whole-body doses were mostly determined by tablet and laptop use. The modeling of RF doses provides valuable input to epidemiological research and to potential risk management regarding RF exposure in young people.

Understanding the interaction of microwave and RF radiation with biological systems is facilitated through knowledge of the actions and characteristics of microwave and RF radiation in space and time. The chapter begins with the pertinent physical laws that govern the interaction of microwave radiation with biological systems. It provides the basic information on antenna radiation characteristics and microwave reflection and transmission at biological interfaces, and also describes RF electromagnetic fields in the near- and far-zone of radiating antennas. It shows that the interactions are functions of the source frequency and configuration, shape and size of the exposed subjects, and orientation and location of the subject with respect to the source, among others.

International audience; Herein we present the assessment of RF-induced cell membrane effects assessment in multicellular spheroids, which are three-dimensional tissue models resembling small avascular tumors. The RF exposure was performed in a dedicated RF applicator, which allowed a precise RF metrology as well as calibrated and systematized conditions of application of electromagnetic fields to multiple 3D multicellular spheroids. The used RF micro-device allowed us varying different RF parameters (such as frequency, power, or modulation) in order to evaluate RFrelated biological effects on the membranes of cells constituting the multicellular spheroids. The effects of electromagnetic signals were assessed on cancer cells spheroids made with HCT-116 cells. Appraised parameters included the evaluation of cell membrane integrity, and the assessment of spheroids global structure after illumination. After RF exposure at Specific Absorption Rate values ranging from 0.4 to 37 kW/kg (attaining a thermal increment ΔTmax up to 6°C), we did not observe any detrimental effects on the membrane level. Moreover, the spheroids exhibited an unmodified architecture.

The mobile phone is one of the most unavoidable electronic gadgets in our day-to-day life. As all devices are fully automated through the Internet of Things (IoT), a mobile phone help us controlling and connecting with other devices. In spite of many advantages of the use of mobile phones in the field of communication automation, the RF radiation from mobile phones or towers is causing many health issues. The main drawback of this effect is not known initially but the effect becomes adverse after a long period. This paper lists the impact of mobile phones both on the positive and negative side. Further research is done to avoid the RF exposure in the field of communication and absorbing material to reduce the impact. As the effect of prolonged use of mobile phones is known only after long time, the general suggestions on their use are listed to avoid deadly diseases and other psychological effects.

The effect of mobile tower radiation on child health in an ecologically sensitive area of Western Ghats in Idukki, Kerala is studied. In this paper, we have attempted to discover whether any relation exists between the RF exposure and the health of children under 15 years old. At some point of path of this work, twenty common diseases were considered. From our analysis, it has been discovered that five of them are very much related to RF exposure. Furthermore, the age group between ten to fifteen years is more vulnerable to mobile tower radiation, and boys are observed to be more affected than girls. In the region under study, exposure levels were well below the ICNIRP recommendations and the current Indian standards. However, still it is inadequate to safeguard children. So it is recommended to modify the current Indian standard of RF exposure.

The objective of this work is to develop and optimize a system to evaluate the effects of RF exposure on biological cell cultures, operating at a wide range of frequencies using multiple specific absorption rate (SAR) distributions simultaneously. In-vitro RF exposure measurements are time-consuming, and in order to show meaningful statistical results, multiple measurements are required. Additionally, many parameters may have to be varied to evaluate the effects of frequency, dosimetry, time, etc., leading to a long series of measurements that can be quite time consuming. Here, we propose a system that is able to achieve multiple optimized SAR distributions by varying the dosage of the cell culture medium in each well of a multi-well plate. Additionally, the setup avoids any resonating modes by using RF absorbers placed around the antenna and the multi-well plate, making it functional at a wide range of frequencies.

This paper analyzes the problem about the growing concern regarding the effects of mobile phone radiofrequency (RF) radiation on human brainwave signals using complex techniques to capture these effects such as interviews and analysis of electroencephalography (EEG). While interviewing among 200 participants provide subjective assessments for the health conditions, EEG gives a noninvasive way of measuring the brainwave activity from sensors placed on the scalp of the human head. So, the aim of this paper is to study the effects of RF exposure from mobile phone on human brainwaves, which can provide information about the mental state of the individual.

Exposure to radiofrequency (RF) power deposition during magnetic resonance imaging (MRI) induces elevated body-tissue temperatures and may cause changes in heart and breathing rates, disturbing thermoregulation. Eleven temperature sensors were placed in muscle tissue and one sensor in the rectum (measured in 10 cm depth) of 20 free-breathing anesthetized pigs to verify temperature curves during RF exposure. Tissue temperatures and heart and breathing rates were measured before, during, and after RF exposure. Pigs were placed into a 60-cm diameter whole-body resonator of a 3 T MRI system. Nineteen anesthetized pigs were divided into four RF exposure groups: sham (0 W/kg), low-exposure (2.7 W/kg, mean exposure time 56 min), moderate-exposure (4.8 W/kg, mean exposure time 31 min), and high-exposure (4.4 W/kg, mean exposure time 61 min). One pig was exposed to a whole-body specific absorption rate (wbSAR) of 11.4 W/kg (extreme-exposure). Hotspot temperatures, measured by sensor 2, increased by mean 5.0 ± 0.9°C, min 3.9; max 6.3 (low), 7.0 ± 2.3°C, min 4.6; max 9.9 (moderate), and 9.2 ± 4.4°C, min 6.1, max 17.9 (high) compared with 0.3 ± 0.3°C in the sham-exposure group (min 0.1, max 0.6). Four time-temperature curves were identified: sinusoidal, parabolic, plateau, and linear. These curve shapes did not correlate with RF intensity, rectal temperature, breathing rate, or heart rate. In all pigs, rectal temperatures increased (2.1 ± 0.9°C) during and even after RF exposure, while hotspot temperatures decreased after exposure. When rectal temperature increased by 1°C, hotspot temperature increased up to 42.8°C within 37 min (low-exposure) or up to 43.8°C within 24 min (high-exposure). Global wbSAR did not correlate with maximum hotspot. Bioelectromagnetics. 2021;42:37-50. © 2020 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.

Purpose This paper presents a method to search for the worst-case configuration leading to the highest RF exposure for a multiconfiguration implantable fixation system under MRI. Methods A two-step method combining an artificial neural network and a genetic algorithm is developed to achieve this purpose. In the first step, the level of RF exposure in terms of peak 1-g and/or 10-g averaged specific absorption rate (SAR1g/10g ), related to the multiconfiguration system, is predicted using an artificial neural network. A genetic algorithm is then used to search for the worst-case configuration of this multidimensional nonlinear problem within both the enumerated discrete sample space and generalized continuous sample space. As an example, a generic plate system with a total of 576 configurations is used for both 1.5T and 3T MRI systems. Results The presented method can effectively identify the worst-case configuration and accurately predict the SAR1g/10g with no more than 20% of the samples in the studied discrete sample space, and can even predict the worst case in the generalized continuous sample space. The worst-case prediction error in the generalized continuous sample space is less than 1.6% for SAR1g and less than 1.3% for SAR10g compared with the simulation results. Conclusion The combination of an artificial neural network with genetic algorithm is a robust technique to determine the worst-case RF exposure level for a multiconfiguration system, and only needs a small amount of training data from the entire system.

Purpose To facilitate assessment of RF power deposition and temperature rise within the breast, we present a method to seamlessly join heterogeneous breast models with standard whole-body models and demonstrate simulations at 7 T. Methods Finite-difference time-domain electromagnetic and bioheat simulations are performed to analyze the specific absorption rate (SAR) and temperature rise distributions in 36 Breast Imaging Reporting and Data System (BI-RADS) categorized breast models fused to 2 female whole-body models while transmitting from a 7T breast volume coil. The breast models are uncompressed in the prone position and feature heterogeneous tissue contents; fusion with human models uses affine transformation and the level-set method. Results The fusion method produces a continuous transient from the chest region to the posterior portion of breast models while preserving the original volume and shape of breast models. Simulation results of both Ella and Hanako models indicate that the maximum local SAR, partial body SAR, and local tissue temperature rise are positively correlated with both breast density and the highest BI-RADS density classification. Additionally, maximum local tissue temperature rise is positively correlated with maximum 10-g SAR values. Conclusion Fibroglandular tissue content plays an important role in the distribution of SAR and temperature rise within breast tissue. The combined body-breast models preserve the integrity of breast models while concurrently exhibiting the loading of whole-body human models. The procedures presented in this simulation study facilitate safety assessments for breast MRI across the population at both clinical and ultrahigh field strengths.

Given the increased public concern about the deleterious biological consequences of radiofrequency electromagnetic fields (RF-EMFs), the involvement of RF-EMFs in neurodegenerative diseases, especially Alzheimer’s disease (AD), has received increased consideration. To investigate the effect of long-term RF-EMF exposure on AD progression, we exposed 5xFAD mice to 1950 MHz RF-EMF at a specific absorption rate of 5.0 W/kg for 2 h/day and 5 days/week for 8 months. Behavioral changes were assessed by an open field test and an object recognition memory task after RF exposure was terminated. In addition, cerebral glucose metabolism was analyzed in the brains of the 5xFAD mice using 18F-deoxyglucose positron emission tomography. The hyperactivity-like and anxiolytic behaviors of the 5xFAD mice in open field tests were rescued by RF exposure. Furthermore, long-term RF-EMF exposure improved the cognitive deficits of 5xFAD mice that were observed in the object recognition memory test. Consistent with the behavioral changes, glucose metabolism in the hippocampus and amygdala regions of the brains of 5xFAD mice following RF exposure was significantly increased compared to glucose metabolism in the brains of sham-exposed mice. These data suggest that long-term exposure to RF-EMF might exert beneficial effects on AD in 5xFAD mice.

In this paper, we present the detailed life-time dosimetry analysis for rodents exposed in the reverberation exposure system designed for the two-year cancer bioassay study conducted by the National Toxicology Program of the National Institute of Environmental Health Sciences. The study required the well-controlled and characterized exposure of individually housed, unrestrained mice at 1900 MHz and rats at 900 MHz, frequencies chosen to give best uniformity exposure of organs and tissues. The wbSAR, the peak spatial SAR, and the organ specific SAR as well as the uncertainty and variation due to the exposure environment, differences in the growth rates, and animal posture were assessed. Compared to the wbSAR, the average exposure of the high-water-content tissues (blood, heart, lung) were higher by $\sim$ 4 dB, while the low-loss tissues (bone and fat) were less by $\sim$ 9 dB. The maximum uncertainty over the exposure period for the SAR was estimated to be $ 49% ( k = 2) for the rodents whereas the relative uncertainty between the exposure groups was $ 14% ( k = 1). The instantaneous variation (averaged over 1 min) was $ 13% ( k = 1), which is small compared to other long term exposure research projects. These detailed dosimetric results empowers comparison with other studies and provides a reference for studies of long-term biological effects of exposure

The health effects of radio-frequency (RF) and microwave radiation have been a subject of scientific inquiry and public interest of late because of widespread global usage of mobile communication devices by billions of people everywhere. A minute increase in health risks such as cancer from RF radiation might lead to significant consequences for the health of the general public. A recent U.S. government announcement about the discovery of rare cancers in rats exposed to RF radiation is an important occurrence. Note that any new or single report should not be viewed in isolation. The U.S. government project was organized to confront the weaknesses of prior laboratory rodent studies on the potential of RF exposure to impact human health such as cancer in controlled environments. Indeed, several published reports on animal cancer investigations involving prolonged exposure to RF radiation are contentious and perplexing. The discrepancies have presented ambiguity in assessing public health threats from RF exposure. It is the objective of this review to provide a critical and analytical synopsis and assessment on current progress in cancers in rats exposed to lifelong RF and microwave radiation. Its focus is on laboratory studies involving cancer production and promotion, as well as the survival of experimental rats. Of special interest is carcinogenesis in the head—cancer development in the head. The question of whether RF exposure from wireless and mobile devices and systems poses a health risk will likely remain equivocal and controversial for some time to come.

The paper, based on the technical specification ISO TS 10974, assesses the safety of Standard Active Implantable Medical Devices (S-AIMD) exposed to RF exposure of MRI devices at 64 MHz (1.5 T). A modelled implant has a form of a normalized wire lead that is typically used as a feeding electrode of cardiac pacemakers or deep brain stimulators. Such an elongated implant was placed in standarized tissue mim-icking liquid phantom. In the current investigation, the electro-thermal analyses of S-AIMD based on the finite-difference time-domain (FDTD) method is presented and the temperature around the implant was estimated with the Fourier Law. In addition, the specific absorption rate (SAR) distribution on the axis of the wire-implant is evaluated and compared to the ISO standard. Importantly, the presented procedure may be helpful during the MRI exposure risk assessment for AIMD patients.

The SAR (Specific Absorption Rate) simulations due to mobile devices operated in close range to the human head and body are described in this paper. The FDTD (Finite-Difference Time-Domain) numerical method together with realistic children, adolescents and adults' models are employed to estimate the 1 g and the 10 g SAR in different biological tissues. Typical mobile phones, laptops, tablets and virtual reality glasses were considered and the alternatives to reduce the SAR are discussed. The need of new dosimetric parameters and skin and nervous system models for 5G and millimetric waves exposure are also addressed.

A novel radio-wave exposure equipment system is developed for studies on thermal perception thresholds of biological effects exposed to millimeter-wave at 70 GHz band that is one of 5th generation wireless systems (5G) candidate frequency band. To achieve high duty RF exposure on living body at 70 GHz required, we newly designed a lens antenna that can irradiate focused beam. In order to obtain basic exposure performance of the developed equipment, we used physical phantom that simulated human's skin and achieved experimental measurements of temperature rise during at 70 GHz band millimeter-wave exposure. After 60 seconds exposure, the temperature on expected area of the phantom surface increased 0.6 degree Celsius. In summary, developed equipment can achieve required high exposure on the sample.

In this paper, a fast prediction method using a 3-layer feed-forward artificial neural network (ANN) based on complex shape descriptors was proposed to estimate the radio-frequency (RF) exposure for complex-shaped implantable devices under magnetic resonance imaging (MRI). The inputs of the ANN consist of 20 parameters based on dimensions and surface-based features of the complex-shaped devices, and the output is the peak MRI RF exposure, in terms of 1-gram averaged specific absorption rate (SAR1g), for the device. This method is implemented and validated with 408 complex-shaped trauma implantable devices. These accurate 3D CAD models are used to numerically calculate the peak SAR1g of the devices by using a full-wave electromagnetic solver based on finite-difference time-domain (FDTD) method. Among the 408 devices, 326 were used to train the neural network, while 82 were utilized to examine the validity of the SAR1g values predicted by the ANN. The results have shown that the correlation between the estimation and the target values was larger than 0.993, and the root mean square error was less than 6.21 W/kg.

Currently whole-body transmit RF coils are the most common RF environment for testing. These RF exposure systems designed for testing of devices are commercially available and currently used in a clinical setting; however, even though head-only transmit/receive (TX/RCV) coils are available on MRI scanners, there is not a validated head-only RF exexposure system available for either 64 or 128 MHz. Testing of active implantable medical devices (AIMDs) is guided by the requirements described in ISO 10974:2018(E). Determining the effects radiofrequency (RF) fields have on AIMDS in an MRI system are of paramount importance. Implanted medical devices in the head and neck experience a different local electric field when being imaged head-only exexposure system. This is a significant difference in local electric field when exposed to a head-only transmit coil versus being exposed to a whole-body transmit coil. To adequately evaluate the safety of these devices in that environment, head-only RF exposure systems are needed. In this paper we summarize the steps in developing and validating a head-only RF exexposure system that is properly tuned to 64 MHz and matched to 50 ω for the testing of implanted medical devices. These steps include the methods for simulating and developing a head-only RF exexposure system.

The paper investigates the possibility of using Software Defined Radio (SDR) platforms in assessing exposure to electromagnetic radiation emitted by sources specific to 3G and 4G generations. Critical parameters of SDR platforms that can limit their performance are the sampling frequency and the receiving resolution of the analog to digital converter (ADC). The performed tests showed that the 8-bit ADC resolution has an influence on the amplitude’s dynamic range, i.e. when evaluating exposure to high-level signals (greater than -40 dBm), the accuracy is consistently diminished. The sampling frequency influences the bandwidth of the channel, and broadband signals (e.g. 20 MHz – in case of 4G) impose requirements for the performance of the SDR platform. For an average-priced SDR platform, such as HackRF One, measurements can be conducted with an acceptable accuracy at most on 5 MHz bandwidths.

Four specific quality control measures were used to determine the quality of 225 publications on the genetic damage in mammalian cells exposed in vitro and in vivo to RF energy and they were as follows. (i) ‘Blind’ collection/analysis of the data to eliminate individual/observer ‘bias’. (ii) Adequate description of ‘dosimetry’ for independent replication/confirmation. (iii) Inclusion of ‘positive controls’ to confirm the outcomes. (iv) Inclusion of ‘sham-exposed controls’ which are more appropriate to compare the data with those in RF exposure conditions. In addition, meta-analysis of the data reported from 2160 tests was used to obtain the ‘d’ values or effect size or the standardized mean difference between the experimental and control cells. The relationship between d values and the above-mentioned quality control measures was ascertained. In addition, the correlation between the quality control measures and the conclusions (no significant difference between the cells exposed to RF energy and control cells; increased damage in former cells compared with the latter; increased, no significant difference and decreased damage in cells exposed to RF energy in the same experiment; decreased damage in cells exposed to RF energy) reported in the publications was examined.

Radiofrequency (RF) heating was explored to induce accelerated ageing in rice to reduce the time of ageing. RF exposure time and moisture content of rice were set at five levels between 10 and 115 min and 9.5–18.5% respectively using central composite rotatable design. The values of different quality attributes of rice viz., volume expansion ratio (VER), water uptake (WU), gel consistency (GC), adhesiveness (ADH), cohesiveness (COH), amylose content (AC), reducing sugars (RS), free fatty acids (FFA), peak viscosity (PV), final viscosity (FV), and overall acceptability varied between 3.79 and 3.88, 269-281 g/100 g, 80–82 mm, (−) 0.35 - (−)1.12 N, 98.45–119.13, 19.22–19.95%, 0.17–0.21%, 1.9–3.4%, 290.35–349.59 RVU, 260.51–290.45 RVU, and 3–4.8 respectively. Models obtained for all the above quality parameters were highly significant (p ≤ 0.0006). RF treated rice differed significantly in various physico-chemical, cooking, textural and pasting properties as compared to fresh rice. WU, GC, FFA, COH, PV and FV increased significantly (p

Purpose MRI is increasingly used to scan pregnant patients. We investigated the effect of 3 Tesla (T) two-port radiofrequency (RF) shimming in anatomical pregnant women models. Theory and methods RF shimming improves B1+ uniformity, but may at the same time significantly alter the induced current distribution and result in large changes in both the level and location of the absorbed RF energy. In this study, we evaluated the electrothermal exposure of pregnant women in the third, seventh, and ninth month of gestation at various imaging landmarks in RF body coils, including modes with RF shimming. Results Although RF shimmed configurations may lower the local RF exposure for the mother, they can increase the thermal load on the fetus. In worst-case configurations, whole-body exposure and local peak temperatures-up to 40.8°C-are equal in fetus and mother. Conclusions Two-port RF shimming can significantly increase the fetal exposure in pregnant women, requiring further research to derive a very robust safety management. For the time being, restriction to the CP mode, which reduces fetal SAR exposure compared with linear-horizontal polarization modes, may be advisable. Results from this study do not support scanning pregnant patients above the normal operating mode. Magn Reson Med 77:2048-2056, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

The RF exposure guidelines do recognize that an increased local SAR (Specific Absorption Rate) due to metallic implants is possible. In this study, the effect of implantable medical device in human torso region is examined. A simple flat torso phantom is used which a cardiac pacemaker model is implanted in. The local SAR dependencies due to exposure frequency bands were presented. Here, we estimate localized SAR at several candidate frequency bands for 5th generation wireless systems.

There is a growing interest in the usage of radiofrequency radiation (RF) as a noninvasive brain stimulation method. Previously reported data demonstrated that RF exposure caused a change in brain oscillations. Therefore, we aimed to investigate effects of RF on brain oscillation by measuring the auditory response of different brain regions in rats.Rats were randomly divided into three groups (n = 12 per each group): Cage control (C), sham rats (Sh), and rats exposed to 2.1 GHz RF for 2 h/day for 7 days. At the end of the exposure, auditory evoked potentials (AEPs) were recorded at different locations in rats. Latencies and amplitudes of AEPs, evoked power, inter-trial phase synchronization, and auditory evoked gamma responses were obtained in response to an auditory stimulus. Furthermore, TBARS levels and 4-HNE, GFAP, iNOS, and nNOS expressions were evaluated in all groups.Peak-to-peak amplitudes of AEPs were significantly higher in the RF group compared with the Sh group. There is no significant difference in peak latencies of AEPs between groups. Beside, evoked power, inter-trial phase synchronization, and auditory evoked gamma responses were significantly higher in the RF group compared with the Sh group. In addition, the RF group had significantly lower TBARS and 4-HNE levels than the Sh group. There were no significant differences between groups for GFAP, nNOS, and iNOS levels, and between the C and RF groups for all parameters.Our present findings suggest that short-term RF treatment under chosen experimental conditions have statistically significant effect on neuronal networks of rats by probably reducing oxidative damage. However, this effect must be further studied for possible noninvasive brain stimulation.

Wireless communication devices emit nonionizing electromagnetic radiofrequency (RF) fields in the range of 300 MHz to 300 GHz, raising public concern regarding the increasing use of mobile phones and their potential health related risks. The intermediate frequency (IF) EMF (300 Hz to 10 MHz) is also now widely used for wireless power transmission (WPT) or domestic kitchen appliances such as induction heating cooking. Unfortunately, although plenty of research has been conducted on RF, little information exists on the potential health effects associated with the exposure to IF magnetic fields. With growing concerns regarding the potential health hazards, it has become necessary to investigate the risks of IF magnetic fields in more detail.This chapter discusses the biological effects of IF and RF exposure. This chapter is divided into the following three parts: epidemiological study, animal study, and cellular study. In the RF field, the frequency of 2.45 GHz is mainly discussed because of the future use of WPT.

The fifth generation of mobile networks will be based on heterogeneous networks composed of long range macro cells and of medium range small cells to face the tremendous increase of mobile data demand. These small cells will be potentially more numerous than the macro ones, closer to the user and less powerful. This paper is interested in RF exposure assessments in proximity of these small cells. A number of normative measurements have been performed on two trials conducted on commercial networks in France. These measurements have shown that the global average level of exposure induced in an area of 100 meters around the sites is not significantly impacted by the small cells (between 0.17 and 0.55 V/m when small cells are in service and between 0.15 and 0.54 V/m when small cells are off). Very localized and close to the site, maximum values of E field of 1 to 3 V/m have been measured. These maximum values are comparable with levels that the long range antennas of the actual network can induce: in France, in 2016, 1% of the in situ measurements in urban area are above 5.6 V/m.

RF-induced heating of ablation catheters under 1.5T magnetic resonance image (MRI) is studied using combined computational modeling and bench testing. The transfer function of ablation catheters are measured experimentally without simplification. A high-resolution anatomical human model was then used to simulate clinical MRI RF exposure environment. The upper limit of the temperature rise was calculated around two types of catheters, namely a single wire catheter and twin wire catheter. Four different insertion depths between 17.5 cm to 70 cm inside human body model were evaluated, simulating procedure for brain or cardiac ablation. A temperature hotspot was observed around the tip of the catheter with an estimated maximum temperature rise higher than 100oC for the single lead catheter and around 94oC for twin lead catheter, with patient landmark varying from −200 mm to 1000 mm with respect to human eye-center. Three experiments were conducted in a standard phantom to validate this coupled method and it showed a good agreement between direct measurements and predicted heating results.

The increasing use of mobile phones has raised public concern about the possible biological effects of radiofrequency electromagnetic field (RF-EMF) exposure on the human brain. To investigate the potential effect of RF-EMF exposure on the brain, we examined the behaviors and hippocampal morphology of C57BL/6 mice after sub-chronic exposure to RF-EMFs with a relatively high SAR level (5.0 W/kg). We applied a 2-hour daily exposure of WCDMA 1,950 MHz using a reverberation chamber that was designed for whole-body exposure for 60 days. In the behavioral tests, RF-EMF did not alter the physical activity or long-term memory of mice. Moreover, no alteration was found in the neuronal and glial cells in the hippocampus by RF-EMFs. In this study, we showed that sub-chronic whole body RF exposure did not produce memory impairment and hippocampal morphological alteration in C57BL/6 mice.

Relatively high exposures to radiofrequency (RF) fields can occur in the broadcast, medical, and communications industries, as well in occupations that use RF emitting equipment (e.g. law enforcement). Information on exposure to workers employed in these industries and occupations is limited. We present results of an Israeli National Survey of occupational RF field levels at frequencies between ~100 kHz and 40 GHz, representing Industrial Heating, Communications, Radar, Research, and Medicine. Almost 4300 measurements from 900 sources across 25 occupations were recorded and categorised as 'routine', 'incidental', or 'unintended'. The occupation-specific geometric means (GMs) of the percentage of the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs) for each of the three exposure scenarios are presented together with the geometric standard deviation (GSD). Additionally, we present estimates of occupation-specific annual personal exposures and collective exposures. The vast majority of the GM of routine exposures ranged from a fraction to less than 1% of ACGIH TLVs, except for Walkie-Talkie (GM 94% of ACGIH), Induction Heating (17%), Plastic Welding (11%), Industrial Heating (6%) and Diathermy (6%). The GM of incidental and unintended exposures exceeded the TLV for one and 14 occupations, respectively. In many cases, the within-occupation GSD was very large, and though the medians remained below TLV, variable fractions of these occupations were projected to exceed the TLV. In rank order, Walkie-Talkie, Plastic Welding, and Induction Heating workers had the highest annual cumulative personal exposure. For cumulative collective exposures within an occupation, Walkie-Talkie dominated with 96.3% of the total, reflecting both large population and high personal exposure. A brief exceedance of the TLV does not automatically translate to hazard as RF exposure limits (issued by various bodies, including ACGIH) include a 10-fold safety factor relative to thermal thresholds and are based on a 6 min averaging period.

The use of wireless communication devices, such as tablets or laptops, is increasing among children. Only a few studies assess specific energy absorption rate (SAR) due to exposure from wireless-enabled tablets and laptops, in particular with Worldwide Interoperability for Microwave Access (WiMax) technology. This paper reports the estimation of the interaction between an E-shaped patch antenna (3.5 GHz) and human models, by means of finite-difference time-domain (FDTD) method. Specifically, four different human models (young adult male, young adult female, pre-teenager female, male child) in different exposure conditions (antenna at different distances from the human model, in different positions, and orientations) were considered and whole-body, 10 and 1 g local SAR and magnetic field value (Bmax) were evaluated. From our results, in some worst-case scenarios involving male and female children's exposure, the maximum radiofrequency energy absorption (hot spots) is located in more sensitive organs such as eye, genitals, and breast. Bioelectromagnetics. 39:414-422, 2018. © 2018 Wiley Periodicals, Inc.

The spatial variations of the time-averaged total whole-body SAR due to voice calls within a 3G macrocell are investigated by simulations. The impact of cell size, usage intensity, usage environment and user morphology is investigated. It is shown that within a cell, total SAR values are minimal when uplink exposure equals downlink exposure. Average exposure increases when the cell size increases, when calls are longer and executed indoor, and when executed by children.

Characterizing exposure to radiofrequency (RF) fields from wireless telecommunications technologies during childhood and adolescence is a research priority in investigating the health effects of RF. The Mobi-Expo study aimed to describe characteristics and determinants of cellular phone use in 534 young people (10-24years) in 12 countries. The study used a specifically designed software application installed on smartphones to collect data on the use of wireless telecommunications devices within this age group. The role of gender, age, maternal education, calendar period, and country was evaluated through multivariate models mutually adjusting for all variables. Call number and duration were higher among females compared to males (geometric mean (GM) ratio 1.17 and 1.42, respectively), among 20-24year olds compared to 10-14year olds (GM ratio 2.09 and 4.40, respectively), and among lowest compared to highest social classes (GM ratio 1.52 and 1.58, respectively). The number of SMS was higher in females (GM ratio 1.46) and the middle age group (15-19year olds: GM ratio 2.21 compared to 10-14year olds) and decreased over time. Data use was highest in the oldest age group, whereas Wi-Fi use was highest in the middle age group. Both data and Wi-Fi use increased over time. Large differences in the number and duration of calls, SMS, and data/Wi-Fi use were seen by country, with country and age accounting for up to 50% of the variance. Hands-free and laterality of use did not show significant differences by sex, age, education, study period, or country. Although limited by a convenience sample, these results provide valuable insights to the design, analysis, and interpretation of future epidemiological studies concerning the health effects of exposure resulting from cellular phone use in young people. In addition, the information provided by this research may be used to design strategies to minimize RF exposure; Dans le cadre de l'étude internationale MOBIKIDS, l'objectif de cette étude est de mieux connaitre l'exposition aux radiofréquences des technologies numériques de communications utilisées ppar les jeunes, afin de mieux évaluer leur exposition ds le cadre de l'étude Cas -témoin MOBIKIDS sur les relations entre exposition aux radiofréquences et tumeurs du cerveau chez l'adolescent et le jeune adulte.

Specific absorption rate (SAR) is used as the measure of rate at which radio frequency (RF) energy is absorbed by an object when exposed to an electromagnetic field. The word “SAR” is usually associated with the human exposure to RF/microwave energy from different electromagnetic sources and, therefore, SAR limits have been defined only for human by the government of India. ICNIRP (International Commission on Non-Ionizing Radiation Protection) RF exposure guideline was maintained in India up to 31 August 2012, and thereafter Indian government has reduced the maximum permissible RF exposure levels to one-tenth of ICNIRP guideline with effect from 1 September 2012. On the other side, the whole plant kingdom gets exposed to continuous RF electromagnetic field (24 hours a day, 365 days a year) from cell phone towers that transmit high RF/microwave power for radio coverage. High permittivity and loss parameters are observed in most plants, fruits and vegetables due to high water content and ionic conce...