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Jiao L, Zhang T, Gao P, Zhou C, Mei X, Zhang W, Lu Y, Zhang L, Zhou Z, Yu Z, He M. Exploring and validating heating dynamics in a radio-frequency electromagnetic field-based resonant chamber for mouse hyperthermia research. Electromagn Biol Med 2024; 43:164-175. [PMID: 38859623 DOI: 10.1080/15368378.2024.2361873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/26/2024] [Indexed: 06/12/2024]
Abstract
Mild whole-body hyperthermia has been shown to have anti-tumor effects through an immune-modulating mechanism. Before it is widely applied in the clinic, tremendous mechanistic research in animals is necessary to adhere to evidence-based principles. The radio frequency electromagnetic field (RF-EMF) based heating facility could be a good choice for hyperthermia treatment, but the heating characteristics of a facility, including structure design, electromagnetic and thermal dosimetry, and the biologic effects of hyperthermia, need to be well elucidated. Here, we reported the heating characteristic study on a resonant chamber (RC) excited by a 1800 MHz solid source. The EMF in the RC was stirred by 24 static reflectors, which resulted in the standard deviation of electric field intensity being below 3 dB in the EM homogeneity evaluation. For the exposure scenario, six free-moving mice were loaded into separate cases and exposed simultaneously in the RC. The EMF energy absorption and distribution in exposed mice were calculated with the 12-plane-waves method of numerical simulation. Different levels of core body temperature increment in exposed mice were achieved through regulation of the source output power. Overexpression of heat shock proteins (HSPs) was detected in the liver, lung and muscle, but not in the brain of the exposed mice. The levels of representative inflammatory cytokines in the serum, TNF-α and IL-10 increased post RC exposure. Based on the heating characteristic study and validation, the applied RC would be a qualified heating system for mild whole-body hyperthermia effect research in mice.
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Affiliation(s)
- Lijiao Jiao
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
- Department of Nursing, General Hospital of Northern Theater Command, Shenyang, Liaoning Province, People's Republic of China
| | - Tao Zhang
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Peng Gao
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Chao Zhou
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
- Xizang Autonomous Region, China
| | - Xiang Mei
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Wenjuan Zhang
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Yonghui Lu
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Lei Zhang
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Zhou Zhou
- Center for Neurointelligence, School of Medicine, Chongqing University, Chongqing, China
| | - Zhengping Yu
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
| | - Mindi He
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Department of Occupational Health, Army Medical University, Chongqing, China
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Lee AK, Choi HD. Dosimetric assessment in the brain for downlink EMF exposure in Korean mobile communication networks. ENVIRONMENTAL RESEARCH 2023; 234:116542. [PMID: 37414391 DOI: 10.1016/j.envres.2023.116542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/17/2023] [Accepted: 07/01/2023] [Indexed: 07/08/2023]
Abstract
Because the position and direction of the human body is not fixed in an actual environment, the incidence direction of the electromagnetic field (EMF) from mobile communication base stations, WiFi access points, broadcasting towers, and other far-field sources is arbitrary. To analyze the overall health effects of radio frequency EMF exposure, the dosimetric assessment for such environmental exposures created from an unspecified number of sources in daily life, along with exposures from specific EMF sources, must be quantified. This study is aimed at numerically evaluating the time-averaged specific absorption rate (SAR) of the human brain for environmental EMF exposure in the frequency range of 50-5800 MHz. Whole-body exposure to EMFs that are evenly incident spatially is considered. By comparing the results of several incidence directions and the number of polarizations, an optimal calculation condition has been derived. Finally, based on the results measured in Seoul at the end of 2021, the SAR and daily specific energy absorption (SA) in the brains of both a child and an adult for downlink exposures from 3G to 5G base stations are reported. Comparison results of the daily brain SA for exposure to DL EMF in all 3G to 5G mobile networks and exposure to a 10-min voice call (uplink EMF) using a mobile phone connected to a 4G network show that the SA from the downlinks is much higher than that from the uplinks.
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Affiliation(s)
- Ae-Kyoung Lee
- Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeong-ro, Yuseong-gu, Daejeon, 34129, South Korea.
| | - Hyung-Do Choi
- Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeong-ro, Yuseong-gu, Daejeon, 34129, South Korea
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Human Exposure Assessment to Wearable Antennas: Effect of Position and Interindividual Anatomical Variability. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19105877. [PMID: 35627414 PMCID: PMC9140696 DOI: 10.3390/ijerph19105877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/29/2022] [Accepted: 05/10/2022] [Indexed: 12/10/2022]
Abstract
(1) Background: This work aims to assess the human exposure to the RF-EMFs emitted by a wearable antenna. (2) Methods: a wearable antenna tuned at f = 2.45 GHz was tested by placing it in six realistic configurations relative to a male and female human model. The exposure assessment was performed by means of computational methods to estimate the SAR10g distributions at 1W of input power. (3) Results: (i) for all the configurations the SAR10g distributions resulted always mainly concentrated on a superficial area immediately below the antenna itself; (ii) the obtained values have shown that the configuration with the highest exposure value was when the antenna was posed on the arm; (iii) the exposure tends to be higher for male model. (4) Discussion and Conclusions: This work highlights the importance of performing an exposure assessment when the antenna is placed on the human wearer considering the growth of the wearable technology and its wide variety of fields of application, e.g., medical and military.
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Modelling and Evaluating Electromagnetic Field Exposure in the Multiple-Source Scenario of Using IoT HF RFID Readers. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19063274. [PMID: 35328961 PMCID: PMC8955348 DOI: 10.3390/ijerph19063274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/04/2022] [Accepted: 03/08/2022] [Indexed: 02/01/2023]
Abstract
The aim of this study was to evaluate Specific Absorption Rate (SAR) and induced electric field (Ein) values in the model of a body of a person present near multiple HF RFID readers of a passive proximity integrated circuit card (PICC) working in an IoT application in a public transport vehicle, in order to test the hypothesis that even the simultaneous use of modelled readers does not cause electromagnetic field (EMF) exposure exceeding relevant limits provided for the evaluation of exposure of the general public. SAR and Ein values were evaluated under various exposure scenarios, designed to mimic EMF exposure under realistic conditions of HF RFID readers used on a public bus and covering various reader locations and the presence of a person using a PICC and a bystander. The results obtained from numerical modelling showed that the absorption of EMF emitted continuously by HF RFID readers (located 10 cm away from a body) in the human body may have a significant influence on humans when the PICC reading ranges are longer than 15-23 cm (depending on the class of PICC) for a single reader and when multiple sources of exposure are used in a public transport vehicle-even at reading ranges 15% shorter (13-20 cm).
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Zhang C, Li C, Yang L, Hou W, Du M, Wu T, Chen W. Assessment of Twin Fetal Exposure to Environmental Magnetic and Electromagnetic Fields. Bioelectromagnetics 2022; 43:160-173. [PMID: 35233784 DOI: 10.1002/bem.22397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/28/2021] [Accepted: 02/08/2022] [Indexed: 11/08/2022]
Abstract
Fetal development is vital in the human lifespan. Therefore, it is essential to characterize exposure by a series of typical environmental magnetic and electromagnetic fields. In particular, there has recently been a sharp increase in the twin birth rate. However, lack of appropriate models has prohibited dosimetric evaluation, restricting characterization of the impact of these environmental factors on twins. The present study developed two whole-body pregnant models of 31 and 32 weeks of gestation with twin fetuses and explored several typical exposure scenarios, including 50-Hz uniform magnetic field exposure, local 125-kHz magnetic field (MF), and 13.56-MHz electromagnetic field exposure, as well as wideband planewave radiofrequency (RF) exposure from 20 to 6000 MHz. Finally, dosimetric results were derived. Compared to the singleton pregnancy with similar weeks of gestation, twin fetuses were overexposed at 50-Hz uniform MF, but they were probably underexposed in the RF scenarios with frequencies for wireless communications. Furthermore, the twin fetuses manifested large dosimetric variability compared to the singleton, which was attributed to the incident direction and fetal position. Based on the analysis, the dosimetric results over the entire gestation period were estimated. The results can be helpful to estimate the risk of twin-fetal exposure to electromagnetic fields and examine the conservativeness of the international guidelines.© 2022 Bioelectromagnetics Society.
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Affiliation(s)
- Chen Zhang
- China Academy of Information and Communications Technology, Beijing, China
| | - Congsheng Li
- China Academy of Information and Communications Technology, Beijing, China
| | - Lei Yang
- China Academy of Information and Communications Technology, Beijing, China
| | - Wenjing Hou
- Department of Radiology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Mingshan Du
- Department of Radiology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Tongning Wu
- China Academy of Information and Communications Technology, Beijing, China
| | - Wei Chen
- Department of Radiology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
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Pophof B, Burns J, Danker-Hopfe H, Dorn H, Egblomassé-Roidl C, Eggert T, Fuks K, Henschenmacher B, Kuhne J, Sauter C, Schmid G. The effect of exposure to radiofrequency electromagnetic fields on cognitive performance in human experimental studies: A protocol for a systematic review. ENVIRONMENT INTERNATIONAL 2021; 157:106783. [PMID: 34333292 PMCID: PMC8485020 DOI: 10.1016/j.envint.2021.106783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/05/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The World Health Organization (WHO) is currently assessing the potential health effects of exposure to radiofrequency electromagnetic fields (RF-EMFs) in the general and working population. Related to one such health effect, there is a concern that RF-EMFs may affect cognitive performance in humans. The systematic review (SR) aims to identify, summarize and synthesize the evidence base related to this question. Here, we present the protocol for the planned SR. OBJECTIVES The main objective is to present a protocol for a SR which will evaluate the associations between short-term exposure to RF-EMFs and cognitive performance in human experimental studies. DATA SOURCES We will search the following databases: PubMed, Embase, Web of Science, Scopus, and the EMF-Portal. The reference lists of included studies and retrieved review articles will be manually searched. STUDY ELIGIBILITY AND CRITERIA We will include randomized human experimental studies that assess the effects of RF-EMFs on cognitive performance compared to no exposure or lower exposure. We will include peer-reviewed articles of any publication date in any language that report primary data. DATA EXTRACTION AND ANALYSIS Data will be extracted according to a pre-defined set of forms developed and piloted by the review author team. To assess the risk of bias, we will apply the Rating Tool for Human and Animal Studies developed by NTP/OHAT, supplemented with additional questions relevant for cross-over studies. Where sufficiently similar studies are identified (e.g. the heterogeneity concerning population, exposure and outcome is low and the studies can be combined), we will conduct random-effects meta-analysis; otherwise, we will conduct a narrative synthesis. ASSESSMENT OF CERTAINTY OF EVIDENCE The certainty of evidence for each identified outcome will be assessed according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Performing the review according to this protocol will allow the identification of possible effects of RF-EMFs on cognitive performance in humans. The protocol has been registered in PROSPERO, an open-source protocol registration system, to foster transparency.
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Affiliation(s)
- Blanka Pophof
- Federal Office for Radiation Protection, Competence Centre EMF, Oberschleißheim, Germany.
| | - Jacob Burns
- Institute for Medical Information Processing, Biometry and Epidemiology (IBE), LMU Munich, Germany.
| | - Heidi Danker-Hopfe
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Competence Centre of Sleep Medicine, 12203 Berlin, Germany.
| | - Hans Dorn
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Competence Centre of Sleep Medicine, 12203 Berlin, Germany.
| | | | - Torsten Eggert
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Competence Centre of Sleep Medicine, 12203 Berlin, Germany.
| | - Kateryna Fuks
- Federal Office for Radiation Protection, Oberschleißheim, Germany.
| | - Bernd Henschenmacher
- Federal Office for Radiation Protection, Competence Centre EMF, Oberschleißheim, Germany.
| | - Jens Kuhne
- Federal Office for Radiation Protection, Competence Centre EMF, Oberschleißheim, Germany.
| | - Cornelia Sauter
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Competence Centre of Sleep Medicine, 12203 Berlin, Germany.
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Radio-frequency exposure of the yellow fever mosquito (A. aegypti) from 2 to 240 GHz. PLoS Comput Biol 2021; 17:e1009460. [PMID: 34710086 PMCID: PMC8577778 DOI: 10.1371/journal.pcbi.1009460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 11/09/2021] [Accepted: 09/17/2021] [Indexed: 12/23/2022] Open
Abstract
Fifth generation networks (5G) will be associated with a partial shift to higher carrier frequencies, including wavelengths comparable in size to insects. This may lead to higher absorption of radio frequency (RF) electromagnetic fields (EMF) by insects and could cause dielectric heating. The yellow fever mosquito (Aedes aegypti), a vector for diseases such as yellow and dengue fever, favors warm climates. Being exposed to higher frequency RF EMFs causing possible dielectric heating, could have an influence on behavior, physiology and morphology, and could be a possible factor for introduction of the species in regions where the yellow fever mosquito normally does not appear. In this study, the influence of far field RF exposure on A. aegypti was examined between 2 and 240 GHz. Using Finite Difference Time Domain (FDTD) simulations, the distribution of the electric field in and around the insect and the absorbed RF power were found for six different mosquito models (three male, three female). The 3D models were created from micro-CT scans of real mosquitoes. The dielectric properties used in the simulation were measured from a mixture of homogenized A. aegypti. For a given incident RF power, the absorption increases with increasing frequency between 2 and 90 GHz with a maximum between 90 and 240 GHz. The absorption was maximal in the region where the wavelength matches the size of the mosquito. For a same incident field strength, the power absorption by the mosquito is 16 times higher at 60 GHz than at 6 GHz. The higher absorption of RF power by future technologies can result in dielectric heating and potentially influence the biology of this mosquito.
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Age-dependence of electromagnetic power and heat deposition in near-surface tissues in emerging 5G bands. Sci Rep 2021; 11:3983. [PMID: 33597554 PMCID: PMC7889919 DOI: 10.1038/s41598-021-82458-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 12/07/2020] [Indexed: 12/03/2022] Open
Abstract
With the development of 5th generation (5G) mobile networks people of different ages will be exposed in the upper part of the microwave spectrum. From the perspective of non-ionizing radiation dosimetry, an accurate analysis of age-dependent electromagnetic power deposition and resulting heating is required. In this study, we evaluate the effect of age on exposure at 26 GHz and 60 GHz. A near-surface tissue model illuminated by a plane wave is used to asses the exposure considering both frequency-independent and frequency-dependent limits. The age-related variation of the skin thickness and tissue electromagnetic properties has been considered. Moreover, the blood flow decrease rate has been taken into account to assess the age-dependent heating. Our results demonstrate that the overall variations of the power density, specific absorption rate (SAR) and heating in the near-surface tissues are limited to about 10–15%. These variations are mainly due to the tissue permittivity and blood flow change with age. In contrast to the transmitted power density that increases with age, the peak SAR decreases at both frequencies. The peak steady-state heating increases from 5 to 70 years old by roughly 11% at 26 GHz and 13% at 60 GHz.
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Liorni I, Capstick M, van Wel L, Wiart J, Joseph W, Cardis E, Guxens M, Vermeulen R, Thielens A. EVALUATION OF SPECIFIC ABSORPTION RATE IN THE FAR-FIELD, NEAR-TO-FAR FIELD AND NEAR-FIELD REGIONS FOR INTEGRATIVE RADIOFREQUENCY EXPOSURE ASSESSMENT. RADIATION PROTECTION DOSIMETRY 2020; 190:459-472. [PMID: 32990753 DOI: 10.1093/rpd/ncaa127] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/26/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
The specific absorption rate (SAR) induced by wireless radiofrequency (RF) systems depends on different parameters. Previously, SAR was mainly assessed under conditions of a single frequency and technology and for a limited number of localized RF sources. The current and emerging mobile systems involve a wider range of usage scenarios and are frequently used simultaneously, leading to combined exposures for which almost no exposure evaluation exists. The aim and novelty of this study is to close this gap of knowledge by developing new methods to rapidly evaluate the SAR induced by RF systems in such scenarios at frequencies from 50 MHz to 5.5 GHz. To this aim, analytical methods for SAR estimation in several usage scenarios were derived through a large-scale numerical study. These include subject-specific characteristics, properties of the RF systems and provide an estimation of the SAR in the whole body, tissues and organs, and different brain regions.
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Affiliation(s)
- Ilaria Liorni
- Foundation for Research on Information Technologies in Society (IT'IS), Zeughausstrasse 43, 8004 Zürich, Zurich, Switzerland
| | - Myles Capstick
- Foundation for Research on Information Technologies in Society (IT'IS), Zeughausstrasse 43, 8004 Zürich, Zurich, Switzerland
| | - Luuk van Wel
- Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80178, 3508 TD, Utrecht, the Netherlands
| | - Joe Wiart
- Chaire C2M LTCI, Telecom ParisTech Universitè Paris Saclay, 46 Rue Barrault, 75013 Paris, Paris, France
| | - Wout Joseph
- Department of Information Technology, Ghent University/IMEC, Technologiepark-Zwijnaarde 126, 9052 Ghent, Ghent, Belgium
| | - Elisabeth Cardis
- ISGlobal, Carrer del Rosselló, 132, 08036 Barcelona, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Plaça de la Mercè, 10-12, 08002 Barcelona, Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), C/ Monforte de Lemos 3-5, 28029 Madrid, Madrid, Spain
| | - Mònica Guxens
- ISGlobal, Carrer del Rosselló, 132, 08036 Barcelona, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Plaça de la Mercè, 10-12, 08002 Barcelona, Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), C/ Monforte de Lemos 3-5, 28029 Madrid, Madrid, Spain
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus MC, University Medical Centre, Doctor Molewaterplein 40, 3015 GD Rotterdam, Rotterdam, the Netherlands
| | - Roel Vermeulen
- Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80178, 3508 TD, Utrecht, the Netherlands
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, Utrecht, the Netherlands
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, London, UK
| | - Arno Thielens
- Department of Information Technology, Ghent University/IMEC, Technologiepark-Zwijnaarde 126, 9052 Ghent, Ghent, Belgium
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Radio-Frequency Electromagnetic Field Exposure of Western Honey Bees. Sci Rep 2020; 10:461. [PMID: 31949179 PMCID: PMC6965614 DOI: 10.1038/s41598-019-56948-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 12/19/2019] [Indexed: 12/29/2022] Open
Abstract
Radio-frequency electromagnetic fields (RF-EMFs) can be absorbed in all living organisms, including Western Honey Bees (Apis Mellifera). This is an ecologically and economically important global insect species that is continuously exposed to environmental RF-EMFs. This exposure is studied numerically and experimentally in this manuscript. To this aim, numerical simulations using honey bee models, obtained using micro-CT scanning, were implemented to determine RF absorbed power as a function of frequency in the 0.6 to 120 GHz range. Five different models of honey bees were obtained and simulated: two workers, a drone, a larva, and a queen. The simulations were combined with in-situ measurements of environmental RF-EMF exposure near beehives in Belgium in order to estimate realistic exposure and absorbed power values for honey bees. Our analysis shows that a relatively small shift of 10% of environmental incident power density from frequencies below 3 GHz to higher frequencies will lead to a relative increase in absorbed power of a factor higher than 3.
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Foster KR, Ziskin MC, Balzano Q, Bit-Babik G. Modeling Tissue Heating From Exposure to Radiofrequency Energy and Relevance of Tissue Heating to Exposure Limits: Heating Factor. HEALTH PHYSICS 2018; 115:295-307. [PMID: 29957690 DOI: 10.1097/hp.0000000000000854] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This review/commentary addresses recent thermal and electromagnetic modeling studies that use image-based anthropomorphic human models to establish the local absorption of radiofrequency energy and the resulting increase in temperature in the body. The frequency range of present interest is from 100 MHz through the transition frequency (where the basic restrictions in exposure guidelines change from specific absorption rate to incident power density, which occurs at 3-10 GHz depending on the guideline). Several detailed thermal modeling studies are reviewed to compare a recently introduced dosimetric quantity, the heating factor, across different exposure conditions as related to the peak temperature rise in tissue that would be permitted by limits for local body exposure. The present review suggests that the heating factor is a robust quantity that is useful for normalizing exposures across different simulation models. Limitations include lack of information about the location in the body where peak absorption and peak temperature increases occur in each exposure scenario, which are needed for careful assessment of potential hazards. To the limited extent that comparisons are possible, the thermal model (which is based on Pennes' bioheat equation) agrees reasonably well with experimental data, notwithstanding the lack of theoretical rigor of the model and uncertainties in the model parameters. In particular, the blood flow parameter is both variable with physiological condition and largely determines the steady state temperature rise. We suggest an approach to define exposure limits above and below the transition frequency (the frequency at which the basic restriction changes from specific absorption rate to incident power density) to provide consistent levels of protection against thermal hazards. More research is needed to better validate the model and to improve thermal dosimetry in general. While modeling studies have considered the effects of variation in thickness of tissue layers, the effects of normal physiological variation in tissue blood flow have been relatively unexplored.
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Affiliation(s)
- Kenneth R Foster
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104
| | - Marvin C Ziskin
- Temple University Medical School, 3420 N. Broad Street, Philadelphia, PA 19140
| | - Quirino Balzano
- Department of Electrical and Computer Engineering, University of Maryland, College Park MD 20742
| | - Giorgi Bit-Babik
- Chief Technology Office, Motorola Solutions, Inc., Fort Lauderdale, FL 33322
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Cappiello G, Drizdal T, Mc Ginley B, O’Halloran M, Glavin M, van Rhoon GC, Jones E, Paulides MM. The potential of time-multiplexed steering in phased array microwave hyperthermia for head and neck cancer treatment. ACTA ACUST UNITED AC 2018; 63:135023. [DOI: 10.1088/1361-6560/aaca10] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Thielens A, Bell D, Mortimore DB, Greco MK, Martens L, Joseph W. Exposure of Insects to Radio-Frequency Electromagnetic Fields from 2 to 120 GHz. Sci Rep 2018; 8:3924. [PMID: 29500425 PMCID: PMC5834628 DOI: 10.1038/s41598-018-22271-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/20/2018] [Indexed: 11/22/2022] Open
Abstract
Insects are continually exposed to Radio-Frequency (RF) electromagnetic fields at different frequencies. The range of frequencies used for wireless telecommunication systems will increase in the near future from below 6 GHz (2 G, 3 G, 4 G, and WiFi) to frequencies up to 120 GHz (5 G). This paper is the first to report the absorbed RF electromagnetic power in four different types of insects as a function of frequency from 2 GHz to 120 GHz. A set of insect models was obtained using novel Micro-CT (computer tomography) imaging. These models were used for the first time in finite-difference time-domain electromagnetic simulations. All insects showed a dependence of the absorbed power on the frequency. All insects showed a general increase in absorbed RF power at and above 6 GHz, in comparison to the absorbed RF power below 6 GHz. Our simulations showed that a shift of 10% of the incident power density to frequencies above 6 GHz would lead to an increase in absorbed power between 3–370%.
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Affiliation(s)
- Arno Thielens
- Department of Information Technology, Ghent University - imec, Ghent, B-9052, Belgium. .,Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley Wireless Research Center, Berkeley, CA, 94704, USA.
| | - Duncan Bell
- Department of Science and Technology, Faculty of Health and Science, University of Suffolk, Ipswitch, IP30AQ, United Kingdom
| | - David B Mortimore
- Newbourne Solutions Ltd, Newbourne, Woodbridge, IP12 4NR, United Kingdom
| | - Mark K Greco
- Charles Sturt University, Medical Imaging, SDHS, Faculty of Science, Wagga Wagga, NSW 2678, Australia
| | - Luc Martens
- Department of Information Technology, Ghent University - imec, Ghent, B-9052, Belgium
| | - Wout Joseph
- Department of Information Technology, Ghent University - imec, Ghent, B-9052, Belgium
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Qureshi MRA, Alfadhl Y, Chen X, Peyman A, Maslanyj M, Mann S. Assessment of exposure to radio frequency electromagnetic fields from smart utility meters in GB; part II) numerical assessment of induced SAR within the human body. Bioelectromagnetics 2017; 39:200-216. [PMID: 29143352 DOI: 10.1002/bem.22094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 09/28/2017] [Indexed: 11/07/2022]
Abstract
Human body exposure to radiofrequency electromagnetic waves emitted from smart meters was assessed using various exposure configurations. Specific energy absorption rate distributions were determined using three anatomically realistic human models. Each model was assigned with age- and frequency-dependent dielectric properties representing a collection of age groups. Generalized exposure conditions involving standing and sleeping postures were assessed for a home area network operating at 868 and 2,450 MHz. The smart meter antenna was fed with 1 W power input which is an overestimation of what real devices typically emit (15 mW max limit). The highest observed whole body specific energy absorption rate value was 1.87 mW kg-1 , within the child model at a distance of 15 cm from a 2,450 MHz device. The higher values were attributed to differences in dimension and dielectric properties within the model. Specific absorption rate (SAR) values were also estimated based on power density levels derived from electric field strength measurements made at various distances from smart meter devices. All the calculated SAR values were found to be very small in comparison to International Commission on Non-Ionizing Radiation Protection limits for public exposure. Bioelectromagnetics. 39:200-216, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Muhammad R A Qureshi
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom
| | - Yasir Alfadhl
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom
| | - Xiaodong Chen
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom
| | - Azadeh Peyman
- Radiation Dosimetry Department, Public Health England, Oxford, United Kingdom
| | - Myron Maslanyj
- Radiation Dosimetry Department, Public Health England, Oxford, United Kingdom
| | - Simon Mann
- Radiation Dosimetry Department, Public Health England, Oxford, United Kingdom
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15
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Thielens A, Martens L, Joseph W. Comments on assessment of polarization dependence of body shadow effect on dosimetry measurements in 2.4GHz band. Bioelectromagnetics 2017; 38:648-649. [DOI: 10.1002/bem.22080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/06/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Arno Thielens
- Department of Information Technology; Ghent University; TechLane Ghent Science Park 15 B-9052Ghent Belgium
| | - Luc Martens
- Department of Information Technology; Ghent University; TechLane Ghent Science Park 15 B-9052Ghent Belgium
| | - Wout Joseph
- Department of Information Technology; Ghent University; TechLane Ghent Science Park 15 B-9052Ghent Belgium
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16
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Wang J, Chen B, Qi H, Zhang J, Chen S, Wang X. DOSIMETRIC VARIATION IN HUMAN EXPOSURE TO 20 MHZ-3 GHZ ELECTROMAGNETIC FIELDS DUE TO CHANGES IN DIELECTRIC PROPERTIES. RADIATION PROTECTION DOSIMETRY 2017; 173:325-332. [PMID: 26891791 DOI: 10.1093/rpd/ncw010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/01/2016] [Indexed: 06/05/2023]
Abstract
Specific energy absorption rate (SAR) is often used to assess human exposure to electromagnetic radiation. SAR is strongly related to incident field parameters, characteristics of the body exposed, ground effects and other factors. In this study, changes in dielectric properties, due to health and age status, were taken into account in the simulation of SAR in a Chinese male model exposed to eight orthogonal plane-wave configurations at the frequency range of 20 MHz-3 GHz. The results show that changes in dielectric properties can cause variations in SAR. Moreover, the variation in SAR was influenced by frequency, electric polarisation and incident direction. Therefore, it is of great significance to distinguish the frequency and exposure configuration when a change in dielectric properties is applied in the evaluation of SAR. In addition, more general cases with a random change in dielectric properties should be performed, which are more realistic.
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Affiliation(s)
- Jiamin Wang
- Department of Physics, East China Normal University, Shanghai 200241, China
| | - Bingxin Chen
- Department of Physics, East China Normal University, Shanghai 200241, China
| | - Hongxing Qi
- Department of Physics, East China Normal University, Shanghai 200241, China
| | - Jie Zhang
- Department of Physics, East China Normal University, Shanghai 200241, China
| | - Shude Chen
- Department of Physics, East China Normal University, Shanghai 200241, China
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Xianghui Wang
- Department of Physics, East China Normal University, Shanghai 200241, China
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17
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Kok HP, Kotte ANTJ, Crezee J. Planning, optimisation and evaluation of hyperthermia treatments. Int J Hyperthermia 2017; 33:593-607. [PMID: 28540779 DOI: 10.1080/02656736.2017.1295323] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Hyperthermia treatment planning using dedicated simulations of power and temperature distributions is very useful to assist in hyperthermia applications. This paper describes an advanced treatment planning software package for a wide variety of applications. METHODS The in-house developed C++ software package Plan2Heat runs on a Linux operating system. Modules are available to perform electric field and temperature calculations for many heating techniques. The package also contains optimisation routines, post-treatment evaluation tools and a sophisticated thermal model enabling to account for 3D vasculature based on an angiogram or generated artificially using a vessel generation algorithm. The use of the software is illustrated by a simulation of a locoregional hyperthermia treatment for a pancreatic cancer patient and a spherical tumour model heated by interstitial hyperthermia, with detailed 3D vasculature included. RESULTS The module-based set-up makes the software flexible and easy to use. The first example demonstrates that treatment planning can help to focus the heating to the tumour. After optimisation, the simulated absorbed power in the tumour increased with 50%. The second example demonstrates the impact of accurately modelling discrete vasculature. Blood at body core temperature entering the heated volume causes relatively cold tracks in the heated volume, where the temperature remains below 40 °C. CONCLUSIONS A flexible software package for hyperthermia treatment planning has been developed, which can be very useful in many hyperthermia applications. The object-oriented structure of the source code allows relatively easy extension of the software package with additional tools when necessary for future applications.
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Affiliation(s)
- H P Kok
- a Department of Radiation Oncology , Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands
| | - A N T J Kotte
- b Department of Radiotherapy , University Medical Center Utrecht , Utrecht , The Netherlands
| | - J Crezee
- a Department of Radiation Oncology , Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands
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18
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Thielens A, Vermeeren G, Caytan O, Torfs G, Demeester P, Bauwelinck J, Rogier H, Martens L, Joseph W. Radiofrequency exposure near an attocell as part of an ultra-high density access network. Bioelectromagnetics 2017; 38:295-306. [PMID: 28240792 DOI: 10.1002/bem.22045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 02/10/2017] [Indexed: 11/08/2022]
Abstract
In the future, wireless radiofrequency (RF) telecommunications networks will provide users with gigabit-per-second data rates. Therefore, these networks are evolving toward hybrid networks, which will include commonly used macro- and microcells in combination with local ultra-high density access networks consisting of so-called attocells. The use of attocells requires a proper compliance assessment of exposure to RF electromagnetic radiation. This paper presents, for the first time, such a compliance assessment of an attocell operating at 3.5 GHz with an input power of 1 mW, based on both root-mean-squared electric field strength (Erms ) and peak 10 g-averaged specific absorption rate (SAR10g ) values. The Erms values near the attocell were determined using finite-difference time-domain (FDTD) simulations and measurements by a tri-axial probe. They were compared to the International Commission on Non-Ionizing Radiation Protection's (ICNIRP) reference levels. All measured and simulated Erms values above the attocell were below 5.9 V/m and lower than reference levels. The SAR10g values were measured in a homogeneous phantom, which resulted in an SAR10g of 9.7 mW/kg, and used FDTD simulations, which resulted in an SAR10g of 7.2 mW/kg. FDTD simulations of realistic exposure situations were executed using a heterogeneous phantom, which yielded SAR10g values lower than 2.8 mW/kg. The studied dosimetric quantities were in compliance with ICNIRP guidelines when the attocell was fed an input power <1 mW. The deployment of attocells is thus a feasible solution for providing broadband data transmission without drastically increasing personal RF exposure. Bioelectromagnetics. 38:295-306, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Arno Thielens
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Günter Vermeeren
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Olivier Caytan
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Guy Torfs
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Piet Demeester
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Johan Bauwelinck
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Hendrik Rogier
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Luc Martens
- Department of Information Technology, Ghent University, Ghent, Belgium
| | - Wout Joseph
- Department of Information Technology, Ghent University, Ghent, Belgium
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Chen B, Wang J, Qi H, Zhang J, Chen S, Wang X. The specific absorption rate of tissues in rats exposed to electromagnetic plane waves in the frequency range of 0.05-5 GHz and SARwb in free-moving rats. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:21-28. [PMID: 28220402 DOI: 10.1007/s13246-017-0522-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 01/05/2017] [Indexed: 11/27/2022]
Abstract
As electromagnetic exposure experiments can only be performed on small animals, usually rats, research on the characteristics of specific absorption rate (SAR) distribution in the rat has received increasing interest. A series of calculations, which simulated the SAR in a male rat anatomical model exposed to electromagnetic plane waves ranging from 0.05 to 5 GHz with different incidence and polarization, were conducted. The whole-body-averaged SAR (SARwb) and the tissue-averaged SAR (SARavg) in 20 major tissues were determined. Results revealed that incidence has great impact on SAR in the rat at higher frequencies owing to the skin effect and the effect on SARavg in tissues is much more apparent than that on SARwb; while polarization plays an important role under lower frequencies. Not only the incidence, but also the polarization in the rat keeps changing when the rat is in free movement. Thus, this article discussed a convenient way to obtain relatively accurate SARwb in a free-moving rat.
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Affiliation(s)
- Bingxin Chen
- Department of Physics, East China Normal University, Shanghai, 200241, China
| | - Jiamin Wang
- Department of Physics, East China Normal University, Shanghai, 200241, China
| | - Hongxin Qi
- Department of Physics, East China Normal University, Shanghai, 200241, China
| | - Jie Zhang
- Department of Physics, East China Normal University, Shanghai, 200241, China
| | - Shude Chen
- Department of Physics, East China Normal University, Shanghai, 200241, China.,State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China
| | - Xianghui Wang
- Department of Physics, East China Normal University, Shanghai, 200241, China.
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20
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Bamba A, Joseph W, Boursianis A, Samaras T, Vermeeren G, Thielens A, Martens L. FAST ASSESSMENT OF RF POWER ABSORPTION IN INDOOR ENVIRONMENTS BY ROOM ELECTROMAGNETICS THEORY. RADIATION PROTECTION DOSIMETRY 2016; 171:477-482. [PMID: 26568617 DOI: 10.1093/rpd/ncv468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 09/03/2015] [Accepted: 10/04/2015] [Indexed: 06/05/2023]
Abstract
A fast method to assess radiofrequency (RF) radiation absorption in humans present in realistic indoor environments is proposed. The only required inputs are the room characteristics and the weight and position of the human with respect to the electromagnetic source. The method is compared and validated with full finite-difference time-domain simulations. Various realistic scenarios are investigated, in which one to six human phantoms are present. Whole-body power absorption ranges from 23.5 to 85.9 µW kg-1 with a median deviation of ∼3.1 dB (51 %). While this difference may appear large, it is outbalanced by a calculation time of less than a second for the proposed method compared with ∼17.5 h for a single full-wave electromagnetic simulation.
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Affiliation(s)
- Aliou Bamba
- Department of Information Technology, Ghent University/iMinds Gaston Crommenlaan 8, Box 201, B-9050 Ghent, Belgium
| | - Wout Joseph
- Department of Information Technology, Ghent University/iMinds Gaston Crommenlaan 8, Box 201, B-9050 Ghent, Belgium
| | - Achilles Boursianis
- Radiocommunications Laboratory, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
| | - Theodoros Samaras
- Radiocommunications Laboratory, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
| | - Günter Vermeeren
- Department of Information Technology, Ghent University/iMinds Gaston Crommenlaan 8, Box 201, B-9050 Ghent, Belgium
| | - Arno Thielens
- Department of Information Technology, Ghent University/iMinds Gaston Crommenlaan 8, Box 201, B-9050 Ghent, Belgium
| | - Luc Martens
- Department of Information Technology, Ghent University/iMinds Gaston Crommenlaan 8, Box 201, B-9050 Ghent, Belgium
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21
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Liorni I, Parazzini M, Varsier N, Hadjem A, Ravazzani P, Wiart J. Exposure assessment of one-year-old child to 3G tablet in uplink mode and to 3G femtocell in downlink mode using polynomial chaos decomposition. Phys Med Biol 2016; 61:3237-57. [PMID: 27027265 DOI: 10.1088/0031-9155/61/8/3237] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
So far, the assessment of the exposure of children, in the ages 0-2 years old, to relatively new radio-frequency (RF) technologies, such as tablets and femtocells, remains an open issue. This study aims to analyse the exposure of a one year-old child to these two sources, tablets and femtocells, operating in uplink (tablet) and downlink (femtocell) modes, respectively. In detail, a realistic model of an infant has been used to model separately the exposures due to (i) a 3G tablet emitting at the frequency of 1940 MHz (uplink mode) placed close to the body and (ii) a 3G femtocell emitting at 2100 MHz (downlink mode) placed at a distance of at least 1 m from the infant body. For both RF sources, the input power was set to 250 mW. The variability of the exposure due to the variation of the position of the RF sources with respect to the infant body has been studied by stochastic dosimetry, based on polynomial chaos to build surrogate models of both whole-body and tissue specific absorption rate (SAR), which makes it easy and quick to investigate the exposure in a full range of possible positions of the sources. The major outcomes of the study are: (1) the maximum values of the whole-body SAR (WB SAR) have been found to be 9.5 mW kg(-1) in uplink mode and 65 μW kg(-1) in downlink mode, i.e. within the limits of the ICNIRP 1998 Guidelines; (2) in both uplink and downlink mode the highest SAR values were approximately found in the same tissues, i.e. in the skin, eye and penis for the whole-tissue SAR and in the bone, skin and muscle for the peak SAR; (3) the change in the position of both the 3G tablet and the 3G femtocell significantly influences the infant exposure.
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Affiliation(s)
- I Liorni
- Istituto di Elettronica e di Ingegneria dell'Informazione e delle Telecomunicazioni IEIIT, Consiglio Nazionale delle Ricerche, Milano, Italy
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22
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Balidemaj E, Kok HP, Schooneveldt G, van Lier ALHMW, Remis RF, Stalpers LJA, Westerveld H, Nederveen AJ, van den Berg CAT, Crezee J. Hyperthermia treatment planning for cervical cancer patients based on electrical conductivity tissue properties acquired in vivo with EPT at 3 T MRI. Int J Hyperthermia 2016; 32:558-68. [PMID: 26982889 DOI: 10.3109/02656736.2015.1129440] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Introduction The reliability of hyperthermia treatment planning (HTP) is strongly dependent on the accuracy of the electric properties of each tissue. The values currently used are mostly based on ex vivo measurements. In this study, in vivo conductivity of human muscle, bladder content and cervical tumours, acquired with magnetic resonance-based electric properties tomography (MR-EPT), are exploited to investigate the effect on HTP for cervical cancer patients. Methods Temperature-based optimisation of five different patients was performed using literature-based conductivity values yielding certain antenna settings, which are then used to compute the temperature distribution of the patient models with EPT-based conductivity values. Furthermore, the effects of altered bladder and muscle conductivity were studied separately. Finally, the temperature-based optimisation was performed with patient models based on EPT conductivity values. Results The tumour temperatures for all EPT-based dielectric patient models were lower compared to the optimal tumour temperatures based on literature values. The largest deviation was observed for patient 1 with ΔT90 = -1.37 °C. A negative impact was also observed when the treatment was optimised based on the EPT values. For four patients ΔT90 was less than 0.6 °C; for one patient it was 1.5 °C. Conclusions Electric conductivity values acquired by EPT are higher than commonly used from literature. This difference has a substantial impact on cervical tumour temperatures achieved during hyperthermia. A higher conductivity in the bladder and in the muscle tissue surrounding the tumour leads to higher power dissipation in the bladder and muscle, and therefore to lower tumour temperatures.
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Affiliation(s)
- Edmond Balidemaj
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
| | - Henny Petra Kok
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
| | - Gerben Schooneveldt
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
| | | | - Rob F Remis
- c Circuits and Systems Group, Delft Technical University Technical University , Delft , Netherlands
| | - Lukas J A Stalpers
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
| | - Henrike Westerveld
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
| | - Aart J Nederveen
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
| | | | - Johannes Crezee
- a Department of Radiation Oncology , Academic Medical Centre , Meibergdreef 9 , Amsterdam , 1105 AZ Netherlands
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Thielens A, Vanveerdeghem P, Van Torre P, Gängler S, Röösli M, Rogier H, Martens L, Joseph W. A Personal, Distributed Exposimeter: Procedure for Design, Calibration, Validation, and Application. SENSORS 2016; 16:180. [PMID: 26840320 PMCID: PMC4801557 DOI: 10.3390/s16020180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/25/2016] [Accepted: 01/27/2016] [Indexed: 11/16/2022]
Abstract
This paper describes, for the first time, the procedure for the full design, calibration, uncertainty analysis, and practical application of a personal, distributed exposimeter (PDE) for the detection of personal exposure in the Global System for Mobile Communications (GSM) downlink (DL) band around 900 MHz (GSM 900 DL). The PDE is a sensor that consists of several body-worn antennas. The on-body location of these antennas is investigated using numerical simulations and calibration measurements in an anechoic chamber. The calibration measurements and the simulations result in a design (or on-body setup) of the PDE. This is used for validation measurements and indoor radio frequency (RF) exposure measurements in Ghent, Belgium. The main achievements of this paper are: first, the demonstration, using both measurements and simulations, that a PDE consisting of multiple on-body textile antennas will have a lower measurement uncertainty for personal RF exposure than existing on-body sensors; second, a validation of the PDE, which proves that the device correctly estimates the incident power densities; and third, a demonstration of the usability of the PDE for real exposure assessment measurements. To this aim, the validated PDE is used for indoor measurements in a residential building in Ghent, Belgium, which yield an average incident power density of 0.018 mW/m².
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Affiliation(s)
- Arno Thielens
- Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8, Ghent B-9050, Belgium.
| | - Peter Vanveerdeghem
- Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8, Ghent B-9050, Belgium.
| | - Patrick Van Torre
- Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8, Ghent B-9050, Belgium.
| | - Stephanie Gängler
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland.
- University of Basel, Basel 4051, Switzerland.
| | - Martin Röösli
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland.
- University of Basel, Basel 4051, Switzerland.
| | - Hendrik Rogier
- Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8, Ghent B-9050, Belgium.
| | - Luc Martens
- Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8, Ghent B-9050, Belgium.
| | - Wout Joseph
- Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8, Ghent B-9050, Belgium.
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Vermeeren G, Joseph W, Martens L. SAR compliance assessment of PMR 446 and FRS walkie-talkies. Bioelectromagnetics 2015; 36:517-26. [PMID: 26344699 DOI: 10.1002/bem.21935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 08/13/2015] [Indexed: 11/06/2022]
Abstract
The vast amount of studies on radiofrequency dosimetry deal with exposure due to mobile devices and base station antennas for cellular communication systems. This study investigates compliance of walkie-talkies to exposure guidelines established by the International Commission on Non-Ionizing Radiation Protection and the Federal Communications Committee. The generic walkie-talkie consisted of a helical antenna and a ground plane and was derived by reverse engineering of a commercial walkie-talkie. Measured and simulated values of antenna characteristics and electromagnetic near fields of the generic walkie-talkie were within 2% and 8%, respectively. We also validated normalized electromagnetic near fields of the generic walkie-talkie against a commercial device and observed a very good agreement (deviation <6%). We showed that peak localized specific absorption rate (SAR) induced in the oval flat phantom by the generic walkie-talkie is in agreement with four commercial devices if input power of the generic walkie-talkie is rescaled based on magnetic near field. Finally, we found that SAR of commercial devices is within current SAR limits for general public exposure for a worst-case duty cycle of 100%, that is, about 3 times and 6 times lower than the limit on the 1 g SAR (1.6 W/kg) and 10 g SAR (2 W/kg), respectively. But, an effective radiated power as specified by the Private Mobile Radio at 446 MHz (PMR 446) radio standard can cause localized SAR exceeding SAR limits for 1 g of tissue.
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Affiliation(s)
- Günter Vermeeren
- Department of Information Technology, iMinds/UGent, Ghent, Belgium
| | - Wout Joseph
- Department of Information Technology, iMinds/UGent, Ghent, Belgium
| | - Luc Martens
- Department of Information Technology, iMinds/UGent, Ghent, Belgium
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25
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Characterization and Evaluation of a Commercial WLAN System for Human Provocation Studies. BIOMED RESEARCH INTERNATIONAL 2015; 2015:289152. [PMID: 26180791 PMCID: PMC4477099 DOI: 10.1155/2015/289152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 05/27/2015] [Indexed: 11/18/2022]
Abstract
This work evaluates the complex exposure characteristics of Wireless Local Area Network (WLAN) technology and describes the design of a WLAN exposure system built using commercially available modular parts for the study of possible biological health effects due to WLAN exposure in a controlled environment. The system consisted of an access point and a client unit (CU) with router board cards types R52 and R52n with 18 dBm and 25 dBm peak power, respectively. Free space radiofrequency field (RF) measurements were performed with a field meter at a distance of 40 cm from the CU in order to evaluate the RF exposure at several signal configurations of the exposure system. Finally, the specific absorption rate (SAR) generated by the CU was estimated computationally in the head of two human models. Results suggest that exposure to RF fields of WLAN systems strongly depends on the sets of the router configuration: the stability of the exposure was more constant and reliable when both antennas were active and vertically positioned, with best signal quality obtained with the R52n router board at channel 9, in UDP mode. The maximum levels of peak SAR were far away from the limits of international guidelines with peak levels found over the skin.
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Verhaart RF, Verduijn GM, Fortunati V, Rijnen Z, van Walsum T, Veenland JF, Paulides MM. Accurate 3D temperature dosimetry during hyperthermia therapy by combining invasive measurements and patient-specific simulations. Int J Hyperthermia 2015; 31:686-92. [DOI: 10.3109/02656736.2015.1052855] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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27
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Adibzadeh F, Verhaart RF, Verduijn GM, Fortunati V, Rijnen Z, Franckena M, van Rhoon GC, Paulides MM. Association of acute adverse effects with high local SAR induced in the brain from prolonged RF head and neck hyperthermia. Phys Med Biol 2015; 60:995-1006. [PMID: 25574664 DOI: 10.1088/0031-9155/60/3/995] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
To provide an adequate level of protection for humans from exposure to radio-frequency (RF) electromagnetic fields (EMF) and to assure that any adverse health effects are avoided. The basic restrictions in terms of the specific energy absorption rate (SAR) were prescribed by IEEE and ICNIRP. An example of a therapeutic application of non-ionizing EMF is hyperthermia (HT), in which intense RF energy is focused at a target region. Deep HT in the head and neck (H&N) region involves inducing energy at 434 MHz for 60 min on target. Still, stray exposure of the brain is considerable, but to date only very limited side-effects were observed. The objective of this study is to investigate the stringency of the current basic restrictions by relating the induced EM dose in the brain of patients treated with deep head and neck (H&N) HT to the scored acute health effects. We performed a simulation study to calculate the induced peak 10 g spatial-averaged SAR (psSAR₁₀g) in the brains of 16 selected H&N patients who received the highest SAR exposure in the brain, i.e. who had the minimum brain-target distance and received high forwarded power during treatment. The results show that the maximum induced SAR in the brain of the patients can exceed the current basic restrictions (IEEE and ICNIRP) on psSAR₁₀g for occupational environments by 14 times. Even considering the high local SAR in the brain, evaluation of acute effects by the common toxicity criteria (CTC) scores revealed no indication of a serious acute neurological effect. In addition, this study provides pioneering quantitative human data on the association between maximum brain SAR level and acute adverse effects when brains are exposed to prolonged RF EMF.
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Affiliation(s)
- F Adibzadeh
- Department of Radiation Oncology, Erasmus MC, Daniel den Hoed Cancer Center, Hyperthermia Unit, Rotterdam, The Netherlands
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Adibzadeh F, Bakker JF, Paulides MM, Verhaart RF, van Rhoon GC. Impact of head morphology on local brain specific absorption rate from exposure to mobile phone radiation. Bioelectromagnetics 2014; 36:66-76. [DOI: 10.1002/bem.21885] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 09/20/2014] [Indexed: 11/12/2022]
Affiliation(s)
- Fatemeh Adibzadeh
- Erasmus MC-Cancer Institute; Department of Radiation Oncology; Hyperthermia Unit; Rotterdam The Netherlands
| | - Jurriaan F. Bakker
- Erasmus MC-Cancer Institute; Department of Radiation Oncology; Hyperthermia Unit; Rotterdam The Netherlands
| | - Margarethus M. Paulides
- Erasmus MC-Cancer Institute; Department of Radiation Oncology; Hyperthermia Unit; Rotterdam The Netherlands
| | - René F. Verhaart
- Erasmus MC-Cancer Institute; Department of Radiation Oncology; Hyperthermia Unit; Rotterdam The Netherlands
| | - Gerard C. van Rhoon
- Erasmus MC-Cancer Institute; Department of Radiation Oncology; Hyperthermia Unit; Rotterdam The Netherlands
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Bamba A, Joseph W, Vermeeren G, Thielens A, Tanghe E, Martens L. A formula for human average whole-body SARwbunder diffuse fields exposure in the GHz region. Phys Med Biol 2014; 59:7435-56. [DOI: 10.1088/0031-9155/59/23/7435] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Cabot E, Christ A, Bühlmann B, Zefferer M, Chavannes N, Bakker JF, van Rhoon GC, Kuster N. Quantification of RF-exposure of the fetus using anatomical CAD-models in three different gestational stages. HEALTH PHYSICS 2014; 107:369-381. [PMID: 25271926 DOI: 10.1097/hp.0000000000000129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study analyzes the exposure of pregnant women and their fetuses in three different gestational stages to electromagnetic radiation in the radio frequency range in the near- and the far-field using numerical modeling. For far-field exposure, the power density at which the basic restriction for the whole body SAR is reached is calculated for both the mother and the fetus at whole body resonance and at frequencies between 450 MHz and 2,450 MHz. The near-field exposure is assessed at 450 MHz, 900 MHz, and 2,450 MHz using half wavelength dipoles as generic sources located at different locations around the abdomen of the mother. For the investigated cases, the exposure of the mother is always below or on the order of magnitude of the basic restriction for exposure at the reference level. When applying the reference levels for the general public, the fetus is sufficiently shielded by the mother. However, the basic restrictions for general public exposure can be exceeded in the fetus when the mother is exposed at reference levels for occupational conditions. For plane wave exposure at occupational levels, the whole body SAR in the fetus can exceed the basic restrictions for the general population by at least 1.8 dB, and in the near-field of professional devices, the 10 g SAR can be non-compliant with the product standard for the general public by > 3.5 dB.
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Affiliation(s)
- Eugenia Cabot
- *Foundation for Research on Information Technologies in Society (IT'IS), Zeughausstr. 43, 8004 Zürich, Switzerland; †Schmid & Partner Engineering AG (SPEAG), Zeughausstr. 43, 8004 Zürich, Switzerland; ‡Erasmus MC-Daniel den Hoed Cancer Center, Department of Radiation Oncology, Section Hyperthermia, PO box 5201, NL-3008 AE, Rotterdam, The Netherlands; §ETH Zürich, 8092 Zürich, Switzerland
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Li C, Chen Z, Yang L, Lv B, Liu J, Varsier N, Hadjem A, Wiart J, Xie Y, Ma L, Wu T. Generation of infant anatomical models for evaluating electromagnetic field exposures. Bioelectromagnetics 2014; 36:10-26. [PMID: 25328088 DOI: 10.1002/bem.21868] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 07/06/2014] [Indexed: 11/06/2022]
Abstract
Realistic anatomical modeling is essential in analyzing human exposure to electromagnetic fields. Infants have significant physical and anatomical differences compared with other age groups. However, few realistic infant models are available. In this work, we developed one 12-month-old male whole body model and one 17-month-old male head model from magnetic resonance images. The whole body and head models contained 28 and 30 tissues, respectively, at spatial resolution of 1 mm × 1 mm × 1 mm. Fewer identified tissues in the whole body model were a result of the low original image quality induced by the fast imaging sequence. The anatomical and physical parameters of the models were validated against findings in published literature (e.g., a maximum deviation as 18% in tissue mass was observed compared with the data from International Commission on Radiological Protection). Several typical exposure scenarios were realized for numerical simulation. Dosimetric comparison with various adult and child anatomical models was conducted. Significant differences in the physical and anatomical features between adult and child models demonstrated the importance of creating realistic infant models. Current safety guidelines for infant exposure to radiofrequency electromagnetic fields may not be conservative.
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Affiliation(s)
- Congsheng Li
- China Academy of Telecommunication Research of Ministry of Industry and Information Technology, Beijing, China; College of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing, China
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Fiocchi S, Parazzini M, Liorni I, Samaras T, Ravazzani P. Temperature Increase in the Fetus Exposed to UHF RFID Readers. IEEE Trans Biomed Eng 2014; 61:2011-9. [DOI: 10.1109/tbme.2014.2312023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Serena Fiocchi
- Istituto di Elettronica e di Ingegneria dell'Informazione e delle Telecomunicazioni, CNR Consiglio Nazionale delle Ricerche, Milan, Italy
| | - Marta Parazzini
- Istituto di Elettronica e di Ingegneria dell'Informazione e delle Telecomunicazioni, CNR Consiglio Nazionale delle Ricerche, Milan, Italy
| | - Ilaria Liorni
- Dipartimento di Elettronica, Informazione e Bioingegneria DEIB, Politecnico di Milano, Milan, Italy
| | - Theodoros Samaras
- Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Paolo Ravazzani
- Istituto di Elettronica e di Ingegneria dell'Informazione e delle Telecomunicazioni, CNR Consiglio Nazionale delle Ricerche, Milan, Italy
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CT-based patient modeling for head and neck hyperthermia treatment planning: manual versus automatic normal-tissue-segmentation. Radiother Oncol 2014; 111:158-63. [PMID: 24631148 DOI: 10.1016/j.radonc.2014.01.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 01/10/2014] [Accepted: 01/25/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND PURPOSE Clinical trials have shown that hyperthermia, as adjuvant to radiotherapy and/or chemotherapy, improves treatment of patients with locally advanced or recurrent head and neck (H&N) carcinoma. Hyperthermia treatment planning (HTP) guided H&N hyperthermia is being investigated, which requires patient specific 3D patient models derived from Computed Tomography (CT)-images. To decide whether a recently developed automatic-segmentation algorithm can be introduced in the clinic, we compared the impact of manual- and automatic normal-tissue-segmentation variations on HTP quality. MATERIAL AND METHODS CT images of seven patients were segmented automatically and manually by four observers, to study inter-observer and intra-observer geometrical variation. To determine the impact of this variation on HTP quality, HTP was performed using the automatic and manual segmentation of each observer, for each patient. This impact was compared to other sources of patient model uncertainties, i.e. varying gridsizes and dielectric tissue properties. RESULTS Despite geometrical variations, manual and automatic generated 3D patient models resulted in an equal, i.e. 1%, variation in HTP quality. This variation was minor with respect to the total of other sources of patient model uncertainties, i.e. 11.7%. CONCLUSIONS Automatically generated 3D patient models can be introduced in the clinic for H&N HTP.
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Cecil S, Neubauer G, Rauscha F, Stix G, Müller W, Breithuber C, Glanzer M. Possible risks due to exposure of workers and patients with implants by TETRA transmitters. Bioelectromagnetics 2014; 35:192-200. [DOI: 10.1002/bem.21839] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 12/18/2013] [Indexed: 11/08/2022]
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Thielens A, Vermeeren G, Joseph W, Martens L. Stochastic method for determination of the organ-specific averaged SAR in realistic environments at 950 MHz. Bioelectromagnetics 2013; 34:549-62. [PMID: 23754459 DOI: 10.1002/bem.21799] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 04/28/2013] [Indexed: 11/11/2022]
Abstract
The organ-specific averaged specific absorption rate (SARosa ) in a heterogeneous human body phantom, the Virtual Family Boy, is determined for the first time in five realistic electromagnetic environments at the Global System for Mobile Communications downlink frequency of 950 MHz. We propose two methods based upon a fixed set of finite-difference time-domain (FDTD) simulations for generating cumulative distribution functions for the SARosa in a certain environment: an accurate vectorial cell-wise spline interpolation with an average error lower than 1.8%, and a faster scalar linear interpolation with a maximal average error of 14.3%. These errors are dependent on the angular steps chosen for the FDTD simulations. However, it is demonstrated that both methods provide the same shape of the cumulative distribution function for the studied organs in the considered environments. The SARosa depends on the considered organ and the environment. Two factors influencing the SARosa are investigated for the first time: conductivity over the density ratio of an organ, and the distance of the organ's center of gravity to the body's surface and exterior of the phantom. A non-linear regression with our model provides a correlation of 0.80. The SARosa due to single plane-wave exposure is also investigated; a worst-case single plane-wave exposure is determined for all studied organs and has been compared with realistic SARosa values. There is no fixed worst-case polarization for all organs, and a single plane-wave exposure condition that exceeds 91% of the SARosa values in a certain environment can always be found for the studied organs.
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Affiliation(s)
- Arno Thielens
- Department of Information Technology, Ghent University/iMinds, Ghent, Belgium
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36
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Thielens A, De Clercq H, Agneessens S, Lecoutere J, Verloock L, Declercq F, Vermeeren G, Tanghe E, Rogier H, Puers R, Martens L, Joseph W. Personal distributed exposimeter for radio frequency exposure assessment in real environments. Bioelectromagnetics 2013; 34:563-7. [PMID: 23740872 DOI: 10.1002/bem.21793] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 04/03/2013] [Indexed: 11/07/2022]
Abstract
For the first time, a personal distributed exposimeter (PDE) for radio frequency (RF) measurements is presented. This PDE is designed based on numerical simulations and is experimentally evaluated using textile antennas and wearable electronics. A prototype of the PDE is calibrated in an anechoic chamber. Compared to conventional exposimeters, which only measure in one position on the body, an excellent isotropy of 0.5 dB (a factor of 1.1) and a 95% confidence interval of 7 dB (a factor of 5) on power densities are measured.
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Affiliation(s)
- Arno Thielens
- Wireless & Cable Group, Department of Information Technology, Ghent University/iMinds, Ghent, Belgium
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Paulides MM, Stauffer PR, Neufeld E, Maccarini PF, Kyriakou A, Canters RAM, Diederich CJ, Bakker JF, Van Rhoon GC. Simulation techniques in hyperthermia treatment planning. Int J Hyperthermia 2013; 29:346-57. [PMID: 23672453 PMCID: PMC3711016 DOI: 10.3109/02656736.2013.790092] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract Clinical trials have shown that hyperthermia (HT), i.e. an increase of tissue temperature to 39-44 °C, significantly enhance radiotherapy and chemotherapy effectiveness [1]. Driven by the developments in computational techniques and computing power, personalised hyperthermia treatment planning (HTP) has matured and has become a powerful tool for optimising treatment quality. Electromagnetic, ultrasound, and thermal simulations using realistic clinical set-ups are now being performed to achieve patient-specific treatment optimisation. In addition, extensive studies aimed to properly implement novel HT tools and techniques, and to assess the quality of HT, are becoming more common. In this paper, we review the simulation tools and techniques developed for clinical hyperthermia, and evaluate their current status on the path from 'model' to 'clinic'. In addition, we illustrate the major techniques employed for validation and optimisation. HTP has become an essential tool for improvement, control, and assessment of HT treatment quality. As such, it plays a pivotal role in the quest to establish HT as an efficacious addition to multi-modality treatment of cancer.
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Affiliation(s)
- Margarethus M Paulides
- Hyperthermia Unit, Department of Radiation Oncology, Daniel den Hoed Cancer Centre, Erasmus Medical Centre, Rotterdam, The Netherlands.
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Fiocchi S, Markakis IA, Ravazzani P, Samaras T. SAR exposure from UHF RFID reader in adult, child, pregnant woman, and fetus anatomical models. Bioelectromagnetics 2013; 34:443-52. [DOI: 10.1002/bem.21789] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 02/06/2013] [Indexed: 11/10/2022]
Affiliation(s)
| | | | - Paolo Ravazzani
- National Research Council of Italy (CNR), Institute of Biomedical Engineering; Milan; Italy
| | - Theodoros Samaras
- Department of Physics; Aristotle University of Thessaloniki; Thessaloniki; Greece
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Thielens A, Vermeeren G, Kurup D, Joseph W, Martens L. Compliance boundaries for multiple-frequency base station antennas in three directions. Bioelectromagnetics 2013; 34:465-78. [DOI: 10.1002/bem.21778] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 12/13/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Arno Thielens
- Department of Information Technology; Ghent University/iMinds; Ghent; Belgium
| | - Günter Vermeeren
- Department of Information Technology; Ghent University/iMinds; Ghent; Belgium
| | - Divya Kurup
- Department of Information Technology; Ghent University/iMinds; Ghent; Belgium
| | - Wout Joseph
- Department of Information Technology; Ghent University/iMinds; Ghent; Belgium
| | - Luc Martens
- Department of Information Technology; Ghent University/iMinds; Ghent; Belgium
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Vermeeren G, Joseph W, Martens L. Statistical multi-path exposure method for assessing the whole-body SAR in a heterogeneous human body model in a realistic environment. Bioelectromagnetics 2012; 34:240-51. [PMID: 23124484 DOI: 10.1002/bem.21762] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 09/18/2012] [Indexed: 11/09/2022]
Abstract
Assessing the whole-body absorption in a human in a realistic environment requires a statistical approach covering all possible exposure situations. This article describes the development of a statistical multi-path exposure method for heterogeneous realistic human body models. The method is applied for the 6-year-old Virtual Family boy (VFB) exposed to the GSM downlink at 950 MHz. It is shown that the whole-body SAR does not differ significantly over the different environments at an operating frequency of 950 MHz. Furthermore, the whole-body SAR in the VFB for multi-path exposure exceeds the whole-body SAR for worst-case single-incident plane wave exposure by 3.6%. Moreover, the ICNIRP reference levels are not conservative with the basic restrictions in 0.3% of the exposure samples for the VFB at the GSM downlink of 950 MHz. The homogeneous spheroid with the dielectric properties of the head suggested by the IEC underestimates the absorption compared to realistic human body models. Moreover, the variation in the whole-body SAR for realistic human body models is larger than for homogeneous spheroid models. This is mainly due to the heterogeneity of the tissues and the irregular shape of the realistic human body model compared to homogeneous spheroid human body models.
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Affiliation(s)
- Günter Vermeeren
- Department of Information Technology, Ghent University/Interdisciplinary Institute for Broadband Technology (IBBT), Ghent, Belgium.
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Söderqvist F, Carlberg M, Zetterberg H, Hardell L. Use of wireless phones and serum β-trace protein in randomly recruited persons aged 18-65 years: a cross-sectional study. Electromagn Biol Med 2012; 31:416-24. [PMID: 22989106 DOI: 10.3109/15368378.2012.683224] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND There are studies suggesting effects on sleep from pulse-modulated radiofrequency fields used in mobile and cordless phones. So far, reports of adverse effects in observational studies are of limited value for risk assessment while effects from experimental studies seem to be more consistent but unclear as to their importance for health. The aim of this study was to investigate whether use of wireless phones is associated with lower concentrations of β-trace protein (lipocalin-type prostaglandin D synthase), a key enzyme in the synthesis of prostaglandin D(2), an endogenous sleep-promoting neurohormone. METHODS Three hundred and fourteen people, aged 18-65 years and living in the municipality of Örebro, Sweden, were recruited randomly using the population registry. Total and age-specific linear regression analyses adjusted for known covariates were used to calculate associations between levels of β-trace protein and short- and long-term use of wireless phones. RESULTS Overall, no statistically significant association between use of wireless phones and the serum concentration of β-trace protein was found, neither with respect to short-term nor long-term use. Age-specific analyses, however, yielded negative associations for long-term use (cumulative hours of use) and β-trace protein in the youngest age group (18-30 years). CONCLUSION This study provided no overall evidence of an association between wireless phone use and serum concentrations of β-trace protein. While the findings in the 18-30 year age group indicating lower concentrations with more cumulative hours of use should be further investigated, no causal inferences can be made from the results of the present study.
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Lee AK, Choi HD. Determining the influence of Korean population variation on whole-body average SAR. Phys Med Biol 2012; 57:2709-25. [DOI: 10.1088/0031-9155/57/9/2709] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bakker JF, Paulides MM, Neufeld E, Christ A, Chen XL, Kuster N, van Rhoon GC. Children and adults exposed to low-frequency magnetic fields at the ICNIRP reference levels: theoretical assessment of the induced electric fields. Phys Med Biol 2012; 57:1815-29. [DOI: 10.1088/0031-9155/57/7/1815] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hirata A, Masuda H, Kanai Y, Asai R, Fujiwara O, Arima T, Kawai H, Watanabe S, Lagroye I, Veyret B. Computational modeling of temperature elevation and thermoregulatory response in the brains of anesthetized rats locally exposed at 1.5 GHz. Phys Med Biol 2012; 56:7639-57. [PMID: 22086327 DOI: 10.1088/0031-9155/56/23/019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The dominant effect of human exposures to microwaves is caused by temperature elevation ('thermal effect'). In the safety guidelines/standards, the specific absorption rate averaged over a specific volume is used as a metric for human protection from localized exposure. Further investigation on the use of this metric is required, especially in terms of thermophysiology. The World Health Organization (2006 RF research agenda) has given high priority to research into the extent and consequences of microwave-induced temperature elevation in children. In this study, an electromagnetic-thermal computational code was developed to model electromagnetic power absorption and resulting temperature elevation leading to changes in active blood flow in response to localized 1.457 GHz exposure in rat heads. Both juvenile (4 week old) and young adult (8 week old) rats were considered. The computational code was validated against measurements for 4 and 8 week old rats. Our computational results suggest that the blood flow rate depends on both brain and core temperature elevations. No significant difference was observed between thermophysiological responses in 4 and 8 week old rats under these exposure conditions. The computational model developed herein is thus applicable to set exposure conditions for rats in laboratory investigations, as well as in planning treatment protocols in the thermal therapy.
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Affiliation(s)
- Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
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Wiart J, Hadjem A, Varsier N, Conil E. Numerical dosimetry dedicated to children RF exposure. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:421-7. [DOI: 10.1016/j.pbiomolbio.2011.10.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 10/02/2011] [Indexed: 10/16/2022]
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Laakso I, Hirata A. Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure. Phys Med Biol 2011; 56:7449-71. [PMID: 22080753 DOI: 10.1088/0031-9155/56/23/008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Numerical models of the human thermoregulatory system can be used together with realistic voxel models of the human anatomy to simulate the body temperature increases caused by the power absorption from radio-frequency electromagnetic fields. In this paper, the Pennes bioheat equation with a thermoregulatory model is used for calculating local peak temperatures as well as the body-core-temperature elevation in a realistic human body model for grounded plane-wave exposures at frequencies 39, 800 and 2400 MHz. The electromagnetic power loss is solved by the finite-difference time-domain (FDTD) method, and the discretized bioheat equation is solved by the geometric multigrid method. Human thermoregulatory models contain numerous thermophysiological and computational parameters--some of which may be subject to considerable uncertainty--that affect the simulated core and local temperature elevations. The goal of this paper is to find how greatly the computed temperature is influenced by changes in various modelling parameters, such as the skin blood flow rate, models for vasodilation and sweating, and clothing and air movement. The results show that the peak temperature rises are most strongly affected by the modelling of tissue blood flow and its temperature dependence, and mostly unaffected by the central control mechanism for vasodilation and sweating. Almost the opposite is true for the body-core-temperature rise, which is however typically greatly lower than the peak temperature rise. It also seems that ignoring the thermoregulation and the blood temperature increase is a good approximation when the local 10 g averaged specific absorption rate is smaller than 10 W kg(-1).
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Affiliation(s)
- Ilkka Laakso
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya, Japan.
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Gandhi OP, Morgan LL, de Salles AA, Han YY, Herberman RB, Davis DL. Exposure Limits: The underestimation of absorbed cell phone radiation, especially in children. Electromagn Biol Med 2011; 31:34-51. [DOI: 10.3109/15368378.2011.622827] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bakker JF, Paulides MM, Neufeld E, Christ A, Kuster N, van Rhoon GC. Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: theoretical assessment of the induced peak temperature increase. Phys Med Biol 2011; 56:4967-89. [PMID: 21772085 DOI: 10.1088/0031-9155/56/15/020] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR(wb)) are provided to keep the whole-body temperature increase (T(body, incr)) under 1 °C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR(10g)) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T(incr, max)) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T(incr, max) in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 °C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T(incr, max) as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T(incr, max) for specified durations of exposure.
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Affiliation(s)
- J F Bakker
- Erasmus MC-Daniel den Hoed Cancer Center, Department of Radiation Oncology, Section Hyperthermia, PO Box 5201, NL-3008 AE, Rotterdam, The Netherlands.
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Fiocchi S, Parazzini M, Paglialonga A, Ravazzani P. Computational exposure assessment of electromagnetic fields generated by an RFID system for mother--newborn identity reconfirmation. Bioelectromagnetics 2011; 32:408-16. [PMID: 21328411 DOI: 10.1002/bem.20653] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 01/06/2011] [Indexed: 11/08/2022]
Abstract
Radio frequency identification (RFID) is an innovative technology currently applied in a large number of industrial and consumer applications. The spread of RFID technology does not correspond to a parallel increase in studies on its possible impact on health in terms of electromagnetic field (EMF) exposure. The aim of this paper is to estimate, by computational techniques, the EMF generated by passive RFID systems for mother-newborn identity reconfirmation. The computation was performed on realistic models of newborn and mother for three different reader positions. The compliance with EMF exposure guidelines was investigated as a function of the change in reader-tag specifications (magnetic field threshold and maximum distance of the reader to awake the tag) and time of use of the reader close to the body. The results show that attention should be paid to the identification of the optimal reader-tag technical specifications to be used in this type of application. That should be done by an accurate exposure assessment investigation, in particular for newborn exposure. The need to reduce the exposure time as much as possible indicates the importance of specific training on the practical applications of the RFID (DATALOGIC J-series, Bologna, Italy) device.
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Affiliation(s)
- Serena Fiocchi
- Institute of Biomedical Engineering, National Research Council, Milan, Italy.
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Vermeeren G, Gosselin MC, Kühn S, Kellerman V, Hadjem A, Gati A, Joseph W, Wiart J, Meyer F, Kuster N, Martens L. The influence of the reflective environment on the absorption of a human male exposed to representative base station antennas from 300 MHz to 5 GHz. Phys Med Biol 2010; 55:5541-55. [DOI: 10.1088/0031-9155/55/18/018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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