RF Exposure Research Articles

Radio-frequency triggered heating and drug release using doxorubicin-loaded LSMO nanoparticles for bimodal treatment of breast cancer

Radio-frequency responsive nanomaterials combined with drugs for simultaneous hyperthermia and drug delivery are potential anti-cancer agents. In this study, chitosan coated La0.7Sr0.3MnO3 nanoparticles (C-LSMO NPs) were synthesized and characterized by X-ray diffraction, dynamic light scattering, Fourier transform infra red spectroscopy, vibrating sample magnetometer, scanning electron and atomic force microscopy. Under low radio-frequency (365kHz, RF), C-LSMO NPs (90nm) showed good colloidal stability (+22mV), superparamagnetic nature (15.4 emu/g) and heating capacity (57.4W/g SAR value). Chitosan facilitated doxorubicin entrapment (76%) resulted in DC-LSMO NPs that showed drug release upon a 5min RF exposure. MCF-7 and MDA-MB-231 cancer cells responded to a 5min RF exposure in the presence of bimodal DC-LSMO NPs with a significant decrease in viability to 73% and 88% (Pearson correlation, r=1, P<0.01) respectively, as compared to hyperthermia alone. Internalization of DC-LSMO NPs via the endosomal pathway led to an efficient localization of doxorubicin within the cell nucleus. The ensuing DNA damage, heat shock protein induction, and caspase production triggered apoptotic cell death. Moreover, DC-LSMO NPs successfully restricted the migration of metastatic MDA-MB-231 cancer cells. These data suggest that DC-LSMO NPs are potential bimodal therapeutic agents for cancer treatment and hold promise against disease recurrence and drug resistance.

Biodegradable Radiofrequency Responsive Nanoparticles for Augmented Thermal Ablation Combined with Triggered Drug Release in Liver Tumors.

Radiofrequency ablation (RFA) and doxorubicin (Dox) chemotherapy are separately approved for liver cancer therapy; however, both have limited success in the clinic due to suboptimal/nonuniform heating and systemic side effects, respectively. Here, we report a biodegradable nanoparticle (NP) system showing excellent RF hyperthermic response together with the ability to locally deliver Dox in the liver under RF trigger and control. The nanosystem was prepared by doping a clinically permissible dose (∼4.3 wt %, 0.03 ppm) of stannous ions in alginate nanoparticles (∼100 nm) coloaded with Dox at ∼13.4 wt % concentration and surface conjugated with galactose for targeting asialo-glycoprotein receptors in liver tumors. Targeted NP-uptake and increased cytotoxicity when combined with RF exposure was demonstrated in HEPG2 liver cancer cells. Following in vitro (chicken liver phantom) demonstration of locally augmented RF thermal response, in vivo scintigraphic imaging of 99Tc-labeled NPs was performed to optimize liver localization in Sprague-Dawley (SD) rats. RF ablation was performed in vivo using a cooled-tip probe, and uniformly enhanced (∼44%) thermal ablation was demonstrated with magnetic resonance imaging along with RF-controlled Dox release. In orthotopic rat liver tumor models, real-time infrared imaging revealed significantly higher (∼20 °C) RF thermal response at the tumor site, resulting in uniform augmented ablation (∼80%) even at a low RF power exposure of 15 W for just 1 min duration. Being a clinically acceptable, biodegradable material, alginate nanoparticles hold strong translational potential for augmented RF hyperthermia combined with triggered drug release.

Зависимость глубины радиочастотного повреждения миокарда от исходного сопротивления тканей в различных температурных условиях

ObjectiveThe aim of the study is to analyze the efficacy of RF ablation at different temperature conditions of the surgical area.Methods20 isolated hearts were studied. To evaluate the effectiveness of radio frequency exposure, use was made of two temperature settings: myocardial normothermia (36.6 °C) and myocardial hypothermia (20 °C). The hearts were placed on the electrophysiology bench heated to 36.6 °C; the ablation depth and temperature of the epicardium, endocardium and myocardium at the exposed points were then measured and evaluated. Tissue impedance was measured before and after RF ablation. RF energy was applied by means of a 40 W unipolar irrigated ball electrode over a period of 7 s.ResultsIt was found out that under hypothermia the myocardium has low resistance which hinders adequate heating of its deep layers and in this connection there arises a high risk for recovery of cardiomyocyte membrane potentials and for retention of their function.Conclusion When the ablation time in both temperature settings is the same, RF exposure at low temperatures causes a lesser depth of damage.

Does exposure to environmental radiofrequency electromagnetic fields cause cognitive and behavioral effects in 10-year-old boys?

The relationship between exposure to electromagnetic fields from non-ionizing radiation and adverse human health effects remains controversial. We aimed to explore the association of environmental radiofrequency-electromagnetic fields (RF-EMFs) exposure with neurobehavioral function of children. A subsample of 123 boys belonging to the Environment and Childhood cohort from Granada (Spain), recruited at birth from 2000 through 2002, were evaluated at the age of 9-11 years. Spot electric field measurements within the 100 kHz to 6 GHz frequency range, expressed as both root mean-square (S(RMS) and maximum power density (S(MAX)) magnitudes, were performed in the immediate surrounds of childreńs dwellings. Neurocognitive and behavioral functions were assessed with a comprehensive battery of tests. Multivariate linear and logistic regression models were used, adjusting for potential confounders. All measurements were lower than reference guideline limits, with median S(RMS) and S(MAX) values of 285.94 and 2759.68 μW/m(2), respectively. Most of the cognitive and behavioral parameters did not show any effect, but children living in higher RF exposure areas (above median S(RMS) levels) had lower scores for verbal expression/comprehension and higher scores for internalizing and total problems, and obsessive-compulsive and post-traumatic stress disorders, in comparison to those living in areas with lower exposure. These associations were stronger when S(MAX) values were considered. Although some of our results may suggest that low-level environmental RF-EMF exposure has a negative impact on cognitive and/or behavior development in children; given limitations in the study design and that the majority of neurobehavioral functioning tasks were not affected, definitive conclusions cannot be drawn.

The Effect of Sub-chronic Whole-Body Exposure to a 1,950 MHz Electromagnetic Field on the Hippocampus in the Mouse Brain

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.

PP.40.07

Objective: We report the clinical case of a woman with resistant hypertension treated with renal sympathetic denervation during which was the vasovagal reaction to severe pain. Design and method: Was studied a 68 year old woman with resistant hypertension (seven antihypertensive drugs including diuretic and spironolactone). The patient subsequently underwent radiofrequency ablation of both renal arteries using the Symplicity catheter. Before RDN was performed premedication with morphine and diazepam. The procedure involved 6 ablations in the right renal artery and 6 ablations in the left renal artery. The evaluation of pain intensity was performed during of the procedure using the Numeric Pain Rating Scale. ABMP was measured before and two days after RDN without modifying the antihypertensive drug regimen. Results: During the procedure, there was a severe pain (10 points on a numeric rating scale) and several episodes of vasovagal reactions - blood pressure decreased to 60/30 mm Hg, and heart rate decreased to 19, which required stopping RF exposures. In the first days after RDN a marked hypotensive effect with the development of orthostatic hypotension, office blood pressure decrease from 180/100 mmHg to 110/68 mmHg, and mean 24 h ambulatory blood pressure decrease from 158/96 mmHg to 109/64 mmHg, demand reduction of antihypertensive therapy to 2 drugs. The hypotensive effect persists up to the present time. Conclusions: In our experience, vasovagal reaction in response to severe pain during radiofrequency denervation of the renal arteries, proved a predictor of effectiveness of the procedure. This is probably due to the pronounced vagal innervation branches along the renal arteries.

Simulating MR imaging for the human embryonic heart

Background MRI has evolved to become a safe diagnostic imaging tool for prenatal care. Recent studies have demonstrated its applications in early diagnosis of congenital heart anomalies (Loomba et al. 2011). However, in vivo embryonic MRI presents obstacles associated with small sample size, RF field profile distortion, RF exposure limits, motion etc. Therefore, small structures such as the heart are difficult to image. In clinical practice during the first trimester, MRI scans are reserved only for severe cases and research protocols are not easily approved. Optimization of pulse sequences is not a trivial issue and exploring the entire parameter space is impractical. For this reason simulations of MRI pulse sequences and imaging protocols can be utilized on embryonic and fetal anatomical models. In this study, a simulation framework is presented that allows MR analysis of the embryonic heart in order to investigate the limitations of image resolution and quality. Methods A detailed anatomical model was developed, based on the Multi-Dimensional Human Embryo dataset (Smith et al. 1999). The dataset consisted of 38 transverse slices with Diffusion, T1 weighted and T2 weighted images, acquired at 9.4T. The dataset consisted of a 23 Carnegie stage (approximately 56 days) fixed embryo, with a total of 38 slices and an isotropic voxel size of 156.3μm. A semi-automatic segmentation algorithm was applied to obtain the tissue masks and a 3D model of the human embryo was developed. A recently developed GPU-based (Graphics Processing Units), comprehensive Bloch equation simulator of MR physics was utilized (Xanthis et al. 2014). A Gradient Echo (GE) pulse sequence was applied to the 3-D object with TR=8ms, RF duration=2ms, flip angle=15°, acquisition matrix=400 x 400 and FOV 200mm x 200mm (B0=1.5T). The B1 transmission profile and the receiver coil sensitivity map were simulated using an exponential attenuation function as described by (Wen et al. 1997). A block diagram of the method is shown in Figure 1.

Thermal and elastic response of subcutaneous tissue with different fibrous septa architectures to RF heating: numerical study.

Radiofrequency currents are commonly used in dermatology to treat cutaneous and subcutaneous tissues by heating. The subcutaneous morphology of tissue consists of a fine, collagenous and fibrous septa network enveloping clusters of adipocyte cells. The architecture of this network, namely density and orientation of septa, varies among patients and, furthermore, it correlates with cellulite grading. In this work we study the effect of two clinically relevant fibrous septa architectures on the thermal and elastic response of subcutaneous tissue to the same RF treatment; in particular, we evaluate the thermal damage and thermal stress induced to an intermediate- and a high-density fibrous septa network architecture that correspond to clinical morphologies of 2.5 and 0 cellulite grading, respectively. We used the finite element method to assess the electric, thermal and elastic response of a two-dimensional model of skin, subcutaneous tissue and muscle subjected to a relatively long, constant, low-power RF treatment. The subcutaneous tissue is constituted by an interconnected architecture of fibrous septa and fat lobules obtained by processing micro-MRI sagittal images of hypodermis. As comparison criteria for the RF treatment of the two septa architectures, we calculated the accumulated thermal damage that corresponds to 63% loss in cell viability. Electric currents preferentially circulated through the fibrous septa in the subcutaneous tissue. However, the intensity of the electric field was higher within the fat because it is a poor electric conductor. The power absorption in the fibrous septa relative to that in the fat varied with septum orientation: it was higher in septa with vertical orientation and lower in septa with horizontal orientation. Overall, maximum values of electric field intensity, power absorption and temperature were similar for both fibrous septa architectures. However, the high-density septa architecture (cellulite grade 0) had a more uniform and broader spatial distribution of power absorption, resulting in a larger cross-sectional area of thermal damage (≈1.5 times more). Volumetric strains (expansion and contraction) were small and similar for both network architectures. During the first seconds of RF exposure, the fibrous septa were subjected to thermal expansion regardless of orientation. In the long term, the fibrous septa contracted due to the thermal expansion of fat. Skin and muscle were subjected to significantly higher Von Mises stresses (measure of yield) or distortion energy than the subcutaneous tissue. The distribution of electric currents within subcutaneous tissues depends on tissue morphology. The electric field is more intense in septum oriented along the skin to muscle (top to bottom) direction, creating lines or planes of preferential heating. It follows that the more septum available for preferential heating, the larger the extent of volumetric RF-heating and thermal damage to the subcutaneous tissue. Thermal load alone, imposed by long-exposure to heating up to 50 °C, results in small volumetric expansion and contraction in the subcutaneous tissue. The subcutaneous tissue is significantly less prone to non-reversible deformation by a thermal load than the skin and muscle.

Anti-cancer, pharmacokinetics and tumor localization studies of pH-, RF- and thermo-responsive nanoparticles

The curcumin-encapsulated chitosan-graft-poly(N-vinyl caprolactam) nanoparticles containing gold nanoparticles (Au-CRC-TRC-NPs) were developed by ionic cross-linking method. After “optimum RF exposure” at 40W for 5min, Au-CRC-TRC-NPs dissipated heat energy in the range of ∼42°C, the lower critical solution temperature (LCST) of chitosan-graft-poly(N-vinyl caprolactam), causing controlled curcumin release and apoptosis to cancer cells. Further, in vivo PK/PD studies on swiss albino mice revealed that Au-CRC-TRC-NPs could be sustained in circulation for a week with no harm to internal organs. The colon tumor localization studies revealed that Au-CRC-TRC-NPs were retained in tumor for a week. These results throw light on their feasibility as multi-responsive nanomedicine for RF-assisted cancer treatment modalities.

A Polarization Switched, Narrowband, RF Probe System Using a VCSEL Optical Feed

Microwave detection techniques requiring high penetration are often reliant on the use of centimeter wavelengths. Systems such as these can also potentially be capable of being highly portable as well as being suitable for use in harsh and demanding environments. Further advantages of these systems are that they can also be cost effective, offer low levels of RF exposure, and are of potential use in short range nondestructive evaluation applications. Lack of resolution is overcome by the use of a phase contrast technique. Using antennas specifically developed for this purpose, the use of polarization adds a further measurement plane. The 5-GHz crossed patch design described here utilizes commercially available RF switches for ease of implementation and exhibits typically 22-dB isolation between each orthogonal-linearly polarized plane. This allows independent E-plane measurements to be conducted from a common point. Phase sensitive information is preserved by a low power optical bidirectional transmission system based around directly modulated vertical cavity surface emitting lasers. The use of these techniques in combination enables a high resolution, dual plane scanning system capable of remote operation in demanding environments.

Application of the SAROTA index in real-life scenario

A unique parameter referred to as the SAROTA index which accounts for both the specific absorption rate (SAR) and the over-the-air (OTA) performance of a mobile phone was previously proposed to characterize the real-life exposure. The applicability of the SAROTA index was confirmed using SAR and total radiated power (TRP) data obtained under laboratory conditions wherein the power control (PC) enforced on the mobile phone was implemented artificially. Herein the investigation is extended to measurements conducted for the speech mode of operation in real-life scenarios. Based on the actual PC implemented during the communication with the base station, the instantaneous and average real-life exposure experienced by the mobile phone user is analyzed and compared to the predicted SAROTA index. To capture the PC in real-time, a set of hardware modified phones with embedded network monitoring software are used. The instantaneous uplink transmit power level (TX_LEV) along with various downlink parameters such as the receive signal level (RX_LEV) and received signal quality (RX_QUAL) of the communication link are thus available for performing a comprehensive RF exposure analysis.

SU‐D‐18C‐06: Initial Experience with Implementing MRI Safety Guidelines for Patients with Pacemakers – Medical Physicist Perspective

Purpose:Several institutions have developed MRI guidelines for patients with MR‐unsafe or MR‐conditional pacemakers. Here we highlight the role of a medical physicist in implementing these guidelines for non‐pacemaker dependent patients. Guidelines: Implementing these guidelines requires involvement from several medical specialties and a strong collaboration with the site MRI supervisor to develop a structured workflow. A medical physicist is required to be present during the scan to supervise the MR scanning and to maintain a safety checklist that ensures: 1) uninterrupted patient communication with the technologist, 2) continuous patient physiologic monitoring (e.g. blood pressure and electrocardiography) by a trained nurse, 3) redundant patient vitals monitoring (e.g. pulse oximetry) due to the possibility of in vivo electrocardiography reading fluctuations during image acquisition. A radiologist is strongly recommended to be available to review the images before patients are discharged from the scanner. Pacemaker MRI should be restricted to 1.5T field strength. The MRI sequences should be optimized by the physicist with regards to: a) SAR: limited to &lt;1.5 W/Kg for MR‐unsafe pacemakers in normal operating mode, b) RF exposure time: &lt;30 min, c) Coils: use T/R coils but not restricted to such, d) Artifacts: further optimization of sequences whenever image quality is compromised due to the pacemaker. In particular, cardiac, breast and left‐shoulder MRIs are most susceptible to these artifacts. Possible strategies to lower the SAR include: a) BW reduction, 2) echo‐train‐length reduction, 3) increase TR, 4) decrease number of averages, 5) decrease flip angle, 6) reduce slices and/or a combination of all the options.Conclusion:A medical physicist in collaboration with the MR supervisor plays an important role in the supervision/implementation of safe MR scanning of pacemaker patients. Developing and establishing a workflow has enabled our institution to scan over 30 patients with pacemakers without complications, including 3 cardiac MR exams.

Computation of Temperature Elevation in a Fetus Exposed to Ambient Heat and Radio Frequency Fields

Temperature elevation in the fetus is of concern for excess heat load, including that from radio-frequency exposure. No previous study succeeded in simulating the temperature difference between the mother and fetus. This study develops a thermal model for a pregnant woman, and then applies it to simulate the temperature variations due to ambient heat exposure and RF exposure. When the pregnant woman model is exposed to ambient temperature of 35–45°C, the core temperature elevations in the mother and the fetus are almost identical. Contrarily, the fetal temperature elevation for radio-frequency exposure is higher than that in the mother.

Gold nanoparticles and radiofrequency in experimental models for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal and chemo-refractory cancers, clearly, alternative treatment strategies are needed. We utilized 10nm gold nanoparticles as a scaffold to synthesize nanoconjugates bearing a targeting antibody (cetuximab, C225) and gemcitabine. Loading efficiency of gemcitabine on the gold nanoconjugates was 30%. Targeted gold nanoconjugates in combination with RF were selectively cytotoxic to EGFR expressing Hep3B and SNU449 cells when compared to isotype particles with/without RF (P<0.05). In animal experiments, targeted gold nanoconjugates halted the growth of subcutaneous Hep3B xenografts in combination with RF exposure (P<0.05). These xenografts also demonstrated increased apoptosis, necrosis and decreased proliferation compared to controls. Normal tissues were unharmed. We have demonstrated that non-invasive RF-induced hyperthermia when combined with targeted delivery of gemcitabine is more effective and safe at dosages ~275-fold lower than the current clinically-delivered systemic dose of gemcitabine. From the Clinical EditorIn a model of hepatocellular carcinoma, the authors demonstrate that non-invasive RF-induced hyperthermia applied with cetuximab targeted delivery of Au NP-gemcitabine conjugate is more effective and safe at dosages ~ 275-fold lower than the current clinically-used systemic dose of gemcitabine.

Immunohistochemical localization of brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor in the superior olivary complex of mice after radiofrequency exposure

Raising health concerns about the biological effects from radiofrequency exposure, even with conflicting results, has prompted calls for formulation of a guideline of the biological safety level. Given the close proximity between a mobile phone and the ear, it has been suggested that the central auditory system may be detrimentally influenced by radiofrequency exposure. In the auditory system, neurotrophins are important in the regulation of neuron survival, especially mammalian cochlear neurons. Neurotrophic factors like brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) present in the auditory system are responsible for the maintenance of auditory neurons. BDNF and GDNF may protect against acoustic trauma and prevent from hearing defect. The present study applied radiofrequency at a specific absorption rate (SAR) of 1.6W/kg (E1.6) or 0W/kg group to determine the distribution of BDNF and GDNF in the nuclei of superior olivary complex (SOC). In the E1.6 group, significant decrements of BDNF immunoreactivity (IR) were noted in the lateral superior olive, medial superior olive, superior paraolivary nucleus and medial nucleus of the trapezoid body. GDNF IR was also significantly decreased (p<0.001) in all SOC nuclei of the E1.6 group. The decrease in the IR of these neurotrophic factors in the SOC of the E1.6 group suggests a detrimental effect of RF exposure in the auditory nuclei.

Retracted Article: Radio frequency triggered curcumin delivery from thermo and pH responsive nanoparticles containing gold nanoparticles and its in vivo localization studies in an orthotopic breast tumor model

RF responsive gold nanoparticles containing curcumin encapsulated chitosan-graft-poly(N-vinyl caprolactam) induced apoptosis on 4T1 breast cancer cells on RF exposure.

Study of Cell Tower Radiation and its Health Hazards on human body

In this paper, we present the study of RF radiation from mobile tower and its health effects on human body. Power density of RF radiation from a mobile tower have been measured in close proximity to the mobile base station (GSM 900) at the selected locality in Aizawl, Mizoram, India, which was erected in 2009. Questionnaire was conducted on different health problems faced by the inhabitants living near the base station. The absolute power densities have been measured at different houses which is compared with standard limits given by various authorities like International Commission on Non Ionizing Radiation Protection (ICNIRP), Bioinitiative : 2012 and with the current Indian Standards. Frequency spectrum was analysed at different sites. Different health symptoms of RF exposure faced by the inhabitants within 50m and outside 50m from the tower are analysed and compared. The result is also analysed based on sex. It was found that the inhabitants living within 50m are having more health complaints than those living outside 50m. It was also found that females are having more complaints than males. This type of study is the first time report in the state. Keywords: RF, Non ionizing radiation, Power density, Frequency spectrum, base stations.

Evaluation of epidural and peripheral nerve catheter heating during magnetic resonance imaging.

Many epidural and peripheral nerve catheters contain conducting wire that could heat during magnetic resonance imaging (MRI), requiring removal for scanning. We tested 2 each of 6 brands of regional analgesia catheters (from Arrow International [Reading, Pennsylvania], B. Braun Medical Inc [Bethlehem, Pennsylvania], and Smiths Medical/Portex [Keene, New Hampshire]) for exposure to clinical 1.5- and 3-T MRI. Catheters testing as nonmagnetic were placed in an epidural configuration in a standard human torso-sized phantom, and an MRI pulse sequence applied at the maximum scanner-allowed radiofrequency specific absorption rate (SAR) for 15 minutes. Temperature and SAR exposure were sampled during MRI using multiple fiberoptic temperature sensors. Two catheters (the Arrow StimuCath Peripheral Nerve and B. Braun Medical Perifix FX Epidural) were found to be magnetic and not tested further. At 3 T, exposure of the remaining 3 epidural and 1 peripheral nerve catheter to the scanner's maximum RF exposure elicited anomalous heating of 4°C to 7°C in 2 Arrow Epidural (MultiPort and Flex-Tip Plus) catheters at the entry points. Temperature increases for the other catheters at 3 T, and all catheters at 1.5 T were 1.4°C or less. When normalized to the body-average US Food and Drug Administration guideline SAR of 4 W/kg, maximum projected temperature increases were 0.1°C to 2.5°C at 1.5 T and 0.7°C to 2.7°C at 3 T, except for the Arrow MultiPort Flex-Tip Plus catheter at 3 T whose increase was 14°C. Most but not all catheters can be left in place during 1.5-T MRI scans. Heating of less than 3°C during MRI for most catheters is not expected to be injurious. While heating was lower at 1.5 T versus 3 T, performance differences between products underscore the need for safety testing before performing MRI.

FDTD computation of temperature elevation in the elderly for far-field RF exposures

Core temperature elevation and perspiration in younger and older adults is investigated for plane-wave exposure at whole-body averaged specific absorption rate of 0.4 W kg(-1). Numeric Japanese male model is considered together with a thermoregulatory response formula proposed in the authors' previous study. The frequencies considered were at 65 MHz and 2 GHz where the total power absorption in humans becomes maximal for the allowable power density prescribed in the international guidelines. From the computational results used here, the core temperature elevation in the older adult model was larger than that in the younger one at both frequencies. The reason for this difference is attributable to the difference of sweating, which is originated from the difference in the threshold activating the sweating and the decline in sweating in the legs.

No influence of acute RF exposure (GSM‐900, GSM‐1800, and UMTS) on mouse retinal ganglion cell responses under constant temperature conditions

Possible non-thermal effects of radio frequency electromagnetic fields (RF-EMF) on retinal ganglion cells were studied in vitro under conditions of constant temperature. Isolated mouse retinae were exposed to GSM-900, GSM-1800, and universal mobile telecommunication system (UMTS) RF-EMF applying specific absorption rates (SAR) of 0 (sham), 0.02, 0.2, 2, and 20 W/kg. Temperature was kept constant within ±0.5 to 1 °C for GSM-900 and ±0.5 °C for GSM-1800 and UMTS. Responses of retinal ganglion cells to light stimuli of three intensities (0.5, 16, and 445 lx) were recorded before, during, and up to 35 min after exposure. Experiments were performed under double-blind conditions. Changes in light responses during and after exposure were determined for each condition (RF-EMF; SAR value; light intensity) with respect to the responses before exposure, respectively. Changes were calculated using the Euclidian distance of the n-dimensional response vectors, respectively. Some changes already occurred during sham (0 W/kg) exposure, reflecting the intrinsic variability in retinal ganglion cell responses. Comparison of the distance values from sham exposure with those from actual exposure yielded no significant differences. In addition, linear regression analysis of the distance values versus SAR values yielded no consistent dependence of light response changes. From these results we conclude that RF-EMF exposure at three mobile phone frequencies (GSM-900, GSM-1800, UMTS) and SARs up to 20 W/kg has no acute effects on retinal ganglion cell responses under constant temperature conditions.