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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.

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.

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.

Recent studies have revealed that rodents' physiological responses to low-intensity radiofrequency (RF) electromagnetic fields were similar to thermoregulatory responses to cold conditions. The primary autonomic response to cold exposure is peripheral vasoconstriction that allows rodents to reduce heat loss and maintain a relatively constant internal body temperature. In the present study, we investigated the effects of 900 MHz RF at a low level (SAR of 0.35 W/kg) on tail skin temperature (Ttail ) in rats. We showed that rats exposed to RF had lower Ttail than control rats at ambient temperatures between 27 and 28 °C, suggesting that RF could induce a noticeable degree of vasoconstriction under mild-warm ambient temperatures. This difference in Ttail was suppressed after the intraperitoneal injection of a vasodilator, an α-adrenergic antagonist, confirming the hypothesis of the vasoconstriction in exposed rats. Moreover, like a response to cold stimuli, RF exposure led to increased plasma concentrations of important factors: noradrenaline (a neurotransmitter responsible for vasoconstriction and thermogenesis) and fatty acids (markers of activated thermogenesis). Taken together, these findings indicate that low-intensity RF levels triggered some key physiological events usually associated with responses to cold in rats. © 2021 Bioelectromagnetics Society.

In this study, the radio-frequency (RF) energy exposure of patient assistants was assessed for an open magnetic resonance imaging (MRI) system based on numerical computations of the head and body RF coil. Various poses of the patient assistants were defined to see how poorly they affected the RF energy exposure. For the assessments, the peak spatial-averaged specific absorption rate (SAR) levels were carefully compared with each patient assistant pose based on the finite-difference time domain calculations of RF coil models when the patient was placed in such coils in a 0.3 Tesla open MRI system. Overall, the SAR levels of the patient assistant were much lower than those of the patient. However, significantly increased SAR levels were observed under specific conditions, including a larger loop size of the patient assistants’ arms and a closer distance to the RF coils. A comparably high level of SAR to the patient’s body was also found. More careful investigations are needed to prevent the increase of SAR in patient assistants for open MRI systems at higher field strengths.

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.

International audience; This paper introduces a rigorous and fast procedure for accurate assessment of the peak averaged specific absorption rate (SAR), quantifying the user exposure to the electromagnetic field radiation from new-radio communication devices. Focus is lent to the specific class of user equipment that exploit multiple-input multiple-output (MIMO) technology and using exclusive simultaneous excitations of the active antenna-array system, such as expected on 5G devices. In contrast with the required N(N-1)+1 measurements on traditional SAR systems that only take measurements of the amplitude of the electric field, it is demonstrated in this paper that only N+1 number of measurements are required to evaluate the true SAR of a N-antenna MIMO thanks to using a vector near-field based SAR measurement system.

International audience; Purpose: The present study was conducted to re-evaluate the effect of low-level 1800 MHz RF signals (up to public exposure level for local exposure) on RAS/MAPK activation in live cells. Material and methods: Using molecular probes based on the Bioluminescence Resonance Energy Transfer technique (BRET), we assessed the effect of Continuous wave (CW) and Global System for Mobile (GSM)-modulated 1800 MHz signals (up to 2 W/kg) on ERK and RAS kinases' activity in live HuH7 cells. Results: We found that radiofrequency field (RF) exposure for 24h altered neither basal level of RAS and ERK activation nor the potency of phorbol-12-myristate-13-acetate (PMA) to activate RAS and ERK kinases, whatever the Specific Absorption Rate (SAR) or signal used. However, we found that exposure to GSM-modulated 1800 MHz signals at 2 W/kg decreased the PMA maximal efficacy to activate both RAS and ERK kinases' activity. Exposure with CW 1800 MHz signal at 2 W/kg only decreased maximal efficacy of PMA to activate ERK but not RAS. No effects of RF exposure at 0.5 W/kg was observed on maximal efficacy of PMA to activate either RAS or ERK whatever the signal used. Conclusion: Our results indicate that RF exposure decreases the efficiency of the cascade of events, which, from the binding of PMA to its receptor(s), leads to the activation of RAS and ERK kinases. This effect of RF exposure is reminiscent of RF-induced adaptive response.

Communication technologies based on radiofrequency (RF) propagation bring great benefits to our daily life. However, their rapid expansion raises concerns about possible impacts on public health. At intensity levels below the threshold to produce thermal effects, RF exposure has also recently been reported to elicit biological effects, resembling reactions to cold. The objective of the present study was to investigate the effects of non-thermal RF on body temperature in mice and the related mechanisms. 3-months-old C57BL/6 J mice were exposed to a continuous RF signal at 900 MHz, 20 ± 5 V.m−1 for 7 consecutive days, twice per day during the light phase, for one hour each time. The SAR was 0.16 ± 0.10 W.kg−1. We showed that body temperature patterns in mice change synchronously with the RF exposure periods. Average body temperature in the light phase in the exposed group was higher than in the control group. The expression of the TRPM8 gene was not affected by RF in trigeminal ganglia. Furthermore, the injection of a TRPM8 antagonist did not induce a temperature decrease in exposed mice, as this was the case for sham-controls. These findings indicate that 900 MHz RF exposure at non-thermal level produce a physiological effect on body temperature in mice. However, the involvement of TRPM8 receptors in the mechanism by which RF induced changes in body temperature of mice which remains to be further explored. It must then be assessed if this effect is extrapolable to man, and if this could lead to consequences on health.

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