101
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Jokela K, Laakso I. Dielectric polarization transients in biological tissue moving in a static magnetic field. Bioelectromagnetics 2016; 37:409-22. [DOI: 10.1002/bem.21979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/26/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Kari Jokela
- Radiation and Nuclear Safety Authority (STUK); Helsinki Finland
| | - Ilkka Laakso
- Department of Electrical Engineering and Automation; Aalto University School of Electrical Engineering; Espoo Finland
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102
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Fakhri Y, Alinejad A, Keramati H, Bay A, Avazpour M, Zandsalimi Y, Moradi B, Rasouli Amirhajeloo L, Mirzaei M. Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head. Glob J Health Sci 2016; 8:53967. [PMID: 27157169 PMCID: PMC5064074 DOI: 10.5539/gjhs.v8n9p251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/23/2015] [Indexed: 11/21/2022] Open
Abstract
The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart mobile phones at the frequencies of 900 and 1800 MHz was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone.
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103
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Djalilian HR, Mahboubi H, Haidar YM, Paulick P, Merlo MW, Bachman M. Development of a novel completely-in-the-canal direct-drive hearing device. Laryngoscope 2016; 127:932-938. [PMID: 27546727 DOI: 10.1002/lary.26221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 07/05/2016] [Indexed: 11/08/2022]
Abstract
OBJECTIVES/HYPOTHESIS To develop a novel completely-in-the-canal device capable of directly driving the tympanic membrane (TM) and ossicular chain from the ear canal. STUDY DESIGN Development and feasibility study. METHODS A voice coil actuator design was developed to drive the TM. Bench testing of the device using laser Doppler vibrometry (LDV) and sound recording was performed. Temporal bone studies using LDV were performed using different designs of the contact tip-TM interface to find the most efficient method of sound transmission. Two short-term clinical performance studies were performed using the latest 3-mm-wide device. Comparison was made to natural sound and to the Vibrant SoundBridge floating mass transducer simulator. RESULTS On bench testing, the device was found to have a low (<0.5%) total harmonic distortion in all frequencies above 400 Hz. Temporal bone studies revealed the device was capable of producing vibrations equivalent to 104 to 120 dB sound across most frequencies. The most efficient method of stimulation was when the device was coupled to the malleus. Short-term clinical performance studies indicated that pure tones and complex sound can be presented with the device. The sound quality of the experimental device was rated as better than the SoundBridge simulator device. CONCLUSIONS The direct-drive hearing device is capable of producing a wide range of sound frequencies and amplitudes. The device can transmit complex sound with low power requirements. Further work on the development of the device is needed for long-term and wider clinical use. LEVEL OF EVIDENCE NA Laryngoscope, 127:932-938, 2017.
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Affiliation(s)
- Hamid R Djalilian
- Division of Neurotology and Skull Base Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, U.S.A.,Department of Biomedical Engineering, University of California, Irvine, Irvine, California, U.S.A
| | - Hossein Mahboubi
- Division of Neurotology and Skull Base Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, U.S.A
| | - Yarah M Haidar
- Division of Neurotology and Skull Base Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, U.S.A
| | - Peyton Paulick
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, U.S.A
| | - Mark W Merlo
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, U.S.A
| | - Mark Bachman
- Department of Computer Science and Electrical Engineering, University of California, Irvine, Irvine, California, U.S.A
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104
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"Low-field" intraoperative MRI: a new scenario, a new adaptation. Clin Radiol 2016; 71:1193-8. [PMID: 27524673 DOI: 10.1016/j.crad.2016.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 05/23/2016] [Accepted: 07/03/2016] [Indexed: 01/24/2023]
Abstract
AIM To describe the adaptation of Cruces University Hospital to the use of intraoperative magnetic resonance imaging (ioMRI), and how the acquisition and use of this technology would impact the day-to-day running of the neurosurgical suite. MATERIALS AND METHODS With the approval of the ethics committee, an observational, prospective study was performed from June 2012 to April 2014, which included 109 neurosurgical procedures with the assistance of ioMRI. These were performed using the Polestar N-30 system (PSN30; Medtronic Navigation, Louisville, CO), which was integrated into the operating room. RESULTS A total of 159 procedures were included: 109 cranial surgeries assisted with ioMRI and 50 control cases (no ioMRI use). There were no statistical significant differences when anaesthetic time (p=0.587) and surgical time (p=0.792) were compared; however, an important difference was shown in duration of patient positioning (p<0.0009) and total duration of the procedure (p<0.0009) between both groups. CONCLUSIONS The introduction of ioMRI is necessary for most neurosurgical suites; however, a few things need to be taken into consideration when adapting to it. Increase procedure time, the use of specific MRI-safe devices, as well as a checklist for each patient to minimise risks, should be taken into consideration.
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105
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Aydin M, Taspinar MS, Cakmak ZE, Dumlupinar R, Agar G. Static magnetic field induced epigenetic changes in wheat callus. Bioelectromagnetics 2016; 37:504-11. [DOI: 10.1002/bem.21997] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 07/20/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Murat Aydin
- Faculty of Agriculture; Department of Field Crops; Atatürk University; Erzurum Turkey
| | | | - Zeynep Elibol Cakmak
- Faculty of Science and Arts; Department of Biology; Kırıkkale University; Kırıkkale Turkey
| | - Rahmi Dumlupinar
- Faculty of Science; Department of Biology; Atatürk University; Erzurum Turkey
| | - Guleray Agar
- Faculty of Science; Department of Biology; Atatürk University; Erzurum Turkey
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106
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Zhang J, Meng X, Ding C, Xie L, Yang P, Shang P. Regulation of osteoclast differentiation by static magnetic fields. Electromagn Biol Med 2016; 36:8-19. [PMID: 27355421 DOI: 10.3109/15368378.2016.1141362] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Static magnetic field (SMF) modulates bone metabolism, but little research is concerned with the effects of SMF on osteoclast. Our previous studies show that osteogenic differentiation is strongly correlated with magnetic strength from hypo (500 nT), weak (geomagnetic field, GMF), moderate (0.2 T) to high (16 T) SMFs. We speculated that the intensity that had positive (16 T) or negative (500 nT and 0.2 T) effects on osteoblast differentiation would inversely influence osteoclast differentiation. To answer this question, we examined the profound effects of SMFs on osteoclast differentiation from pre-osteoclast Raw264.7 cells. Here, we demonstrated that 500 nT and 0.2 T SMFs promoted osteoclast differentiation, formation and resorption, while 16 T had an inhibitory effect. Almost all the osteoclastogenic genes were highly expressed under 500 nT and 0.2 T, including RANK, matrix metalloproteinase 9 (MMP9), V-ATPase, carbonic anhydrase II (Car2) and cathepsin K (CTSK), whereas they were decreased under 16 T. In addition, 16 T disrupted actin formation with remarkably decreased integrin β3 expression. Collectively, these results indicate that osteoclast differentiation could be regulated by altering the intensity of SMF, which is just contrary to that on osteoblast differentiation. Therefore, studies of SMF effects could reveal some parameters that could be used as a physical therapy for various bone disorders.
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Affiliation(s)
- Jian Zhang
- a School of Radiation Medicine and Protection , Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , P. R. China.,b Key Laboratory for Space Bioscience and Biotechnology , Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University , Xi'an , P. R. China
| | - Xiaofeng Meng
- b Key Laboratory for Space Bioscience and Biotechnology , Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University , Xi'an , P. R. China
| | - Chong Ding
- b Key Laboratory for Space Bioscience and Biotechnology , Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University , Xi'an , P. R. China
| | - Li Xie
- b Key Laboratory for Space Bioscience and Biotechnology , Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University , Xi'an , P. R. China
| | - Pengfei Yang
- b Key Laboratory for Space Bioscience and Biotechnology , Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University , Xi'an , P. R. China
| | - Peng Shang
- b Key Laboratory for Space Bioscience and Biotechnology , Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University , Xi'an , P. R. China
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107
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DNA double-strand breaks and micronuclei in human blood lymphocytes after repeated whole body exposures to 7T Magnetic Resonance Imaging. Neuroimage 2016; 133:288-293. [DOI: 10.1016/j.neuroimage.2016.03.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/13/2022] Open
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108
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Iachininoto MG, Camisa V, Leone L, Pinto R, Lopresto V, Merla C, Giorda E, Carsetti R, Zaffina S, Podda MV, Teofili L, Grassi C. Effects of exposure to gradient magnetic fields emitted by nuclear magnetic resonance devices on clonogenic potential and proliferation of human hematopoietic stem cells. Bioelectromagnetics 2016; 37:201-11. [PMID: 26992028 DOI: 10.1002/bem.21967] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/26/2016] [Indexed: 01/29/2023]
Abstract
This study investigates effects of gradient magnetic fields (GMFs) emitted by magnetic resonance imaging (MRI) devices on hematopoietic stem cells. Field measurements were performed to assess exposure to GMFs of staff working at 1.5 T and 3 T MRI units. Then an exposure system reproducing measured signals was realized to expose in vitro CD34+ cells to GMFs (1.5 T-protocol and 3 T-protocol). CD34+ cells were obtained by Fluorescence Activated Cell Sorting from six blood donors and three MRI-exposed workers. Blood donor CD34+ cells were exposed in vitro for 72 h to 1.5 T or 3 T-protocol and to sham procedure. Cells were then cultured and evaluated in colony forming unit (CFU)-assay up to 4 weeks after exposure. Results showed that in vitro GMF exposure did not affect cell proliferation but instead induced expansion of erythroid and monocytes progenitors soon after exposure and for the subsequent 3 weeks. No decrease of other clonogenic cell output (i.e., CFU-granulocyte/erythroid/macrophage/megakaryocyte and CFU-granulocyte/macrophage) was noticed, nor exposed CD34+ cells underwent the premature exhaustion of their clonogenic potential compared to sham-exposed controls. On the other hand, pilot experiments showed that CD34+ cells exposed in vivo to GMFs (i.e., samples from MRI workers) behaved in culture similarly to sham-exposed CD34+ cells, suggesting that other cells and/or microenvironment factors might prevent GMF effects on hematopoietic stem cells in vivo. Accordingly, GMFs did not affect the clonogenic potential of umbilical cord blood CD34+ cells exposed in vitro together with the whole mononuclear cell fraction.
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Affiliation(s)
| | - Vincenzo Camisa
- Occupational Medicine/Health Technology Assessment and Safety Research Unit, Clinical-Technological Innovations Research Area-Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Lucia Leone
- Institute of Human Physiology, Università Cattolica, Rome, Italy
| | - Rosanna Pinto
- ENEA, Italian Agency for New Technologies, Energy, and Sustainable Economic Development, Division of Health Protection Technologies, Casaccia Research Centre, Rome, Italy
| | - Vanni Lopresto
- ENEA, Italian Agency for New Technologies, Energy, and Sustainable Economic Development, Division of Health Protection Technologies, Casaccia Research Centre, Rome, Italy
| | - Caterina Merla
- ENEA, Italian Agency for New Technologies, Energy, and Sustainable Economic Development, Division of Health Protection Technologies, Casaccia Research Centre, Rome, Italy
| | - Ezio Giorda
- Immunology Unit, Immunology and Pharmacotherapy Research Area-Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Rita Carsetti
- Immunology Unit, Immunology and Pharmacotherapy Research Area-Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Salvatore Zaffina
- Occupational Medicine/Health Technology Assessment and Safety Research Unit, Clinical-Technological Innovations Research Area-Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | | | - Luciana Teofili
- Department of Transfusion Medicine, Institute of Hematology, Università Cattolica, Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica, Rome, Italy.,San Raffaele Pisana Scientific Institute for Research, Hospitalization and Health Care, Rome, Italy
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Affiliation(s)
- Philipp A Kaufmann
- Department of Nuclear Medicine, University Hospital Zurich, Ramistr 100 (NUK D 6), CH-8091 Zurich, Switzerland
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110
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Romeo S, Sannino A, Scarfì MR, Massa R, d’Angelo R, Zeni O. Lack of effects on key cellular parameters of MRC-5 human lung fibroblasts exposed to 370 mT static magnetic field. Sci Rep 2016; 6:19398. [PMID: 26762783 PMCID: PMC4725921 DOI: 10.1038/srep19398] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 12/07/2015] [Indexed: 01/22/2023] Open
Abstract
The last decades have seen increased interest toward possible adverse effects arising from exposure to intense static magnetic fields. This concern is mainly due to the wider and wider applications of such fields in industry and clinical practice; among them, Magnetic Resonance Imaging (MRI) facilities are the main sources of exposure to static magnetic fields for both general public (patients) and workers. In recent investigations, exposures to static magnetic fields have been demonstrated to elicit, in different cell models, both permanent and transient modifications in cellular endpoints critical for the carcinogenesis process. The World Health Organization has therefore recommended in vitro investigations as important research need, to be carried out under strictly controlled exposure conditions. Here we report on the absence of effects on cell viability, reactive oxygen species levels and DNA integrity in MRC-5 human foetal lung fibroblasts exposed to 370 mT magnetic induction level, under different exposure regimens. Exposures have been performed by using an experimental apparatus designed and realized for operating with the static magnetic field generated by permanent magnets, and confined in a magnetic circuit, to allow cell cultures exposure in absence of confounding factors like heating or electric field components.
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Affiliation(s)
- Stefania Romeo
- CNR – Institute for Electromagnetic Sensing of Environment, Via Diocleziano 328, 80124 Naples, Italy
| | - Anna Sannino
- CNR – Institute for Electromagnetic Sensing of Environment, Via Diocleziano 328, 80124 Naples, Italy
| | - Maria Rosaria Scarfì
- CNR – Institute for Electromagnetic Sensing of Environment, Via Diocleziano 328, 80124 Naples, Italy
| | - Rita Massa
- CNR – Institute for Electromagnetic Sensing of Environment, Via Diocleziano 328, 80124 Naples, Italy
- Department of Physics, University of Naples Federico II, CMSA via Cintia, 80126, Napoli, Italy
| | - Raffaele d’Angelo
- Italian Workers’ Compensation Authority (INAIL)–Regional Technical Advisory Department Risk and Prevention Assessment (CONTARP) of Campania, via Nuova Poggioreale, 80143 Napoli
| | - Olga Zeni
- CNR – Institute for Electromagnetic Sensing of Environment, Via Diocleziano 328, 80124 Naples, Italy
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Lopresto V, Merla C, Pinto R, Benvenuto E. High-intensity static magnetic field exposure devices for in vitro experiments on biopharmaceutical plant factories in aerospace environments. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:893-6. [PMID: 26736406 DOI: 10.1109/embc.2015.7318506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Three high-intensity static magnetic field (SMF) exposure devices have been designed and realized for application to in vitro experimental research on hairy root cultures, supposed to grow in extreme environments- as those of space aircrafts- for producing biopharmaceutical molecules. The devices allow the exposure at two different levels of induction magnetic (B) field (250 mT and 500 mT) plus sham for blind exposure. The exposure levels can be considered representative of possible B-fields experienced within the habitat of a spacecraft in presence of active magnetic shielding systems. Each device can house a single 85-mm diameter Petri dish. Numerical simulations have been performed to accurately evaluate the B-field distribution in the biological target. Numerical results have been confirmed by measured data, proving that designed setups allows exposure to SMFs with a homogeneity better than 90%. The exposure devices will be employed for experiments scheduled within BIOxTREME research project, funded by the Italian Space Agency (ASI).
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112
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Pierce NE, Parell GJ, Jesus ROD, Ojano-Dirain CP, Antonelli PJ. Magnetic resonance imaging in a guinea pig model of inner ear decompression sickness and barotrauma. Laryngoscope 2015; 126:2106-9. [PMID: 26649994 DOI: 10.1002/lary.25811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2015] [Indexed: 11/11/2022]
Abstract
OBJECTIVES/HYPOTHESIS Scuba diving may cause severe hearing loss and vertigo due to inner ear barotrauma and decompression sickness. These may be difficult to differentiate clinically. Decompression sickness requires costly and potentially dangerous hyperbaric therapy, whereas such treatment may worsen barotrauma. The objective of this study was to assess the potential utility of magnetic resonance imaging to identify and distinguish blood from air in the inner ear, manifestations of barotrauma and decompression sickness, using a guinea pig model. STUDY DESIGN Prospective animal trial. METHODS Magnetic resonance of the head was performed at 3 Tesla, pre- and postinjection of 2, 4, or 10 μL of air or blood through the round window into the perilymph. With this model, 2 μL has been shown to cause hearing loss. Images were reviewed by a neuroradiologist blinded to the treatment. RESULTS All 14 normal ears, five of seven blood- and five of seven air-injected ears, were correctly interpreted. Two blood- and one air-injected ear were interpreted as indeterminate. One air-injected ear was incorrectly interpreted as blood. CONCLUSIONS Magnetic resonance reliably distinguishes small volumes of air and blood in the guinea pig inner ear. Magnetic resonance should be evaluated for its utility in the diagnosis of inner ear barotrauma and decompression sickness in scuba divers. LEVEL OF EVIDENCE NA Laryngoscope, 126:2106-2109, 2016.
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Affiliation(s)
- Nathan E Pierce
- Department of Otolaryngology, University of Florida, Gainesville, Florida, U.S.A
| | - G Joseph Parell
- Department of Otolaryngology, University of Florida, Gainesville, Florida, U.S.A
| | - Reordan O De Jesus
- Department of Radiology, University of Florida, Gainesville, Florida, U.S.A
| | | | - Patrick J Antonelli
- Department of Otolaryngology, University of Florida, Gainesville, Florida, U.S.A
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113
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Lei H, Xu Y, Guan R, Li M, Hui Y, Gao Z, Yang B, Xin Z. Effect of gyromagnetic fields on human prostatic adenocarcinoma cells. Onco Targets Ther 2015; 8:3489-97. [PMID: 26648740 PMCID: PMC4664505 DOI: 10.2147/ott.s95306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To investigate the biological effect of gyromagnetic fields (GMFs) on cell proliferation and apoptosis of human prostatic adenocarcinoma cells and explore the underlying mechanisms. METHODS PC-3 cells were grouped into normal control (NC) and GMF treatment groups. Cell proliferation was analyzed with kit-8 and Ki67 immunofluorescence staining, while cell apoptosis was analyzed with flow cytometry double staining of Annexin V-PE/7-AAD. The Akt and p38 MAPK/Caspase signaling pathways were analyzed by western blotting and immunofluorescence staining, and cell polarization was analyzed with PARD3. RESULTS Cell proliferation and activity of the Akt pathway were significantly decreased by the GMF, while cell apoptosis, activity of p38 MAPK, and PARD3-positive cell number were significantly increased in the GMF group compared to the NC group. CONCLUSION GMFs inhibit cell proliferation, induce apoptosis, and regulate tumor cell polarity conditions, potentially through down-regulating Akt, activating the p38 MAPK/Caspase pathway, and promoting PARD3 expression in PC-3 cells.
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Affiliation(s)
- Hongen Lei
- Andrology Center, Peking University First Hospital, Peking University, Beijing, People's Republic of China
| | - Yongde Xu
- Andrology Center, Peking University First Hospital, Peking University, Beijing, People's Republic of China
| | - Ruili Guan
- Andrology Center, Peking University First Hospital, Peking University, Beijing, People's Republic of China
| | - Meng Li
- Department of Urology, General Hospital of Ningxia Medical University, Yinchuan, People's Republic of China
| | - Yu Hui
- Department of Urology, The First Affiliated Hospital of Soochow University, Soochow, People's Republic of China
| | - Zhezhu Gao
- Andrology Center, Peking University First Hospital, Peking University, Beijing, People's Republic of China
| | - Bicheng Yang
- Andrology Center, Peking University First Hospital, Peking University, Beijing, People's Republic of China
| | - Zhongcheng Xin
- Andrology Center, Peking University First Hospital, Peking University, Beijing, People's Republic of China
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114
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Schaap K, Portengen L, Kromhout H. Exposure to MRI-related magnetic fields and vertigo in MRI workers. Occup Environ Med 2015; 73:161-6. [PMID: 26561507 DOI: 10.1136/oemed-2015-103019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/21/2015] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Vertigo has been reported by people working around magnetic resonance imaging (MRI) scanners and was found to increase with increasing strength of scanner magnets. This suggests an association with exposure to static magnetic fields (SMF) and/or motion-induced time-varying magnetic fields (TVMF). This study assessed the association between various metrics of shift-long exposure to SMF and TVMF and self-reported vertigo among MRI workers. METHODS We analysed 358 shifts from 234 employees at 14 MRI facilities in the Netherlands. Participants used logbooks to report vertigo experienced during the work day at the MRI facility. In addition, personal exposure to SMF and TVMF was measured during the same shifts, using portable magnetic field dosimeters. RESULTS Vertigo was reported during 22 shifts by 20 participants and was significantly associated with peak and time-weighted average (TWA) metrics of SMF as well as TVMF exposure. Associations were most evident with full-shift TWA TVMF exposure. The probability of vertigo occurrence during a work shift exceeded 5% at peak exposure levels of 409 mT and 477 mT/s and at full-shift TWA levels of 3 mT and 0.6 mT/s. CONCLUSIONS These results confirm the hypothesis that vertigo is associated with exposure to MRI-related SMF and TVMF. Strong correlations between various metrics of shift-long exposure make it difficult to disentangle the effects of SMF and TVMF exposure, or identify the most relevant exposure metric. On the other hand, this also implies that several metrics of shift-long exposure to SMF and TVMF should perform similarly in epidemiological studies on MRI-related vertigo.
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Affiliation(s)
- Kristel Schaap
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Lützen Portengen
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Hans Kromhout
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
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115
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Zilberti L, Bottauscio O, Chiampi M. Assessment of exposure to MRI motion-induced fields based on the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Magn Reson Med 2015; 76:1291-300. [PMID: 26525160 DOI: 10.1002/mrm.26031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 01/24/2023]
Abstract
PURPOSE The goal of this study was to conduct an exposure assessment for workers moving through the stray stationary field of common MRI scanners, performed according to the recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Guidelines, which aim at avoiding annoying sensory effects. THEORY AND METHODS The analysis was performed through numerical simulations, using a high-resolution anatomical model that moved along realistic trajectories in proximity to a tubular and open MRI scanner. Both dosimetric indexes indicated by ICNIRP (maximum variation of the magnetic flux density vector and exposure index for the motion-induced electric field) were computed for three statures of the human model. RESULTS A total of 51 exposure situations were analyzed. None of them exceeded the limit for the maximum variation of the magnetic flux density, whereas some critical cases were found when computing the induced electric field. In the latter case, the exposure indexes computed via Fourier transform and through an equivalent filter result to be consistent. CONCLUSION The results suggest the adoption of some simple precautionary rules, useful when sensory effects experienced by an operator could reflect upon the patient's safety. Moreover, some open issues regarding the quantification of motion-induced fields are highlighted, putting in evidence the need for clarification at standardization level. Magn Reson Med 76:1291-1300, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica, Torino, Italy.
| | | | - Mario Chiampi
- Politecnico di Torino, Dipartimento Energia, Torino, Italy
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Kottou S, Nikolopoulos D, Yannakopoulos PH, Vogiannis E, Petraki E, Panagiotaras D, Koulougliotis D. Preliminary background indoor EMF measurements in Greece. Phys Med 2015; 31:808-16. [DOI: 10.1016/j.ejmp.2015.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 10/22/2022] Open
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Kaufmann PA. Cardiac Magnetic Resonance Imaging: The Case for Nonionizing Radiation Protection and the Precautionary Principle. Circ Cardiovasc Imaging 2015; 8:e003885. [PMID: 26338878 DOI: 10.1161/circimaging.115.003885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Philipp A Kaufmann
- From the Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland.
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119
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Sliker L, Ciuti G, Rentschler M, Menciassi A. Magnetically driven medical devices: a review. Expert Rev Med Devices 2015; 12:737-52. [PMID: 26295303 DOI: 10.1586/17434440.2015.1080120] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A widely accepted definition of a medical device is an instrument or apparatus that is used to diagnose, prevent or treat disease. Medical devices take a broad range of forms and utilize various methods to operate, such as physical, mechanical or thermal. Of particular interest in this paper are the medical devices that utilize magnetic field sources to operate. The exploitation of magnetic fields to operate or drive medical devices has become increasingly popular due to interesting characteristics of magnetic fields that are not offered by other phenomena, such as mechanical contact, hydrodynamics and thermodynamics. Today, there is a wide range of magnetically driven medical devices purposed for different anatomical regions of the body. A review of these devices is presented and organized into two groups: permanent magnetically driven devices and electromagnetically driven devices. Within each category, the discussion will be further segregated into anatomical regions (e.g., gastrointestinal, ocular, abdominal, thoracic, etc.).
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Affiliation(s)
- Levin Sliker
- a 1 Department of Mechanical Engineering, University of Colorado , Boulder, Colorado 80309-0427, USA
| | - Gastone Ciuti
- b 2 The BioRobotics Institute, Scuola Superiore Sant'Anna , 56025 Pontedera, Pisa, Italy
| | - Mark Rentschler
- a 1 Department of Mechanical Engineering, University of Colorado , Boulder, Colorado 80309-0427, USA
| | - Arianna Menciassi
- b 2 The BioRobotics Institute, Scuola Superiore Sant'Anna , 56025 Pontedera, Pisa, Italy
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120
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Magnets for therapy in the GI tract: a systematic review. Gastrointest Endosc 2015; 82:237-45. [PMID: 25936447 DOI: 10.1016/j.gie.2014.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/04/2014] [Indexed: 12/13/2022]
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121
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[New aspects from legislation, guidelines and safety standards for MRI]. Radiologe 2015. [PMID: 26220129 DOI: 10.1007/s00117-015-2859-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Many aspects of magnetic resonance (MR) operation are not directly regulated by law but in standards, guidelines and the operating instructions of the MR scanner. The mandatory contents of the operating instructions are regulated in a central standard of the International Electrotechnical Commission (IEC) 60601-2-33. In this standard, the application of static magnetic fields in MRI up to 8 Tesla (T) in the clinical routine (first level controlled mode) has recently been approved. Furthermore, the equally necessary CE certification of ultra-high field scanners (7-8 T) in Europe is expected for future devices. The existing installations will not be automatically certified but will retain their experimental status. The current extension of IEC 60601-2-33 introduces a new add-on option, the so-called fixed parameter option (FPO). This option might also be switched on in addition to the established operating modes and defines a fixed device constellation and certain parameters of the energy output of MR scanners designed to simplify the testing of patients with implants in the future.The employment of pregnant workers in an MRI environment is still not generally regulated in Europe. In parts of Germany and Austria pregnant and lactating employees were prohibited from working in the MR control zone (0.5 mT) in 2014. This is based on the mostly unresolved question of the applicability of limits for employees (exposure of extremities to static magnetic fields up to 8 T allowed) or the thresholds for the general population (maximum 400 mT). According to the European Society of Urogenital Radiology (ESUR), the discarding of breast milk after i.v. administration of gadolinium-based contrast agents in the case of a breastfeeding woman is only recommended when using contrast agents in the nephrogenic systemic fibrosis (NSF) high-risk category.
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Paulick PE, Merlo MW, Mahboubi H, Djalilian HR, Bachman M. A micro-drive hearing aid: a novel non-invasive hearing prosthesis actuator. Biomed Microdevices 2015; 16:915-25. [PMID: 25129112 DOI: 10.1007/s10544-014-9896-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The direct hearing device (DHD) is a new auditory prosthesis that combines conventional hearing aid and middle ear implant technologies into a single device. The DHD is located deep in the ear canal and recreates sounds with mechanical movements of the tympanic membrane. A critical component of the DHD is the microactuator, which must be capable of moving the tympanic membrane at frequencies and magnitudes appropriate for normal hearing, with little distortion. The DHD actuator reported here utilized a voice coil actuator design and was 3.7 mm in diameter. The device has a smoothly varying frequency response and produces a precisely controllable force. The total harmonic distortion between 425 Hz and 10 kHz is below 0.5 % and acoustic noise generation is minimal. The device was tested as a tympanic membrane driver on cadaveric temporal bones where the device was coupled to the umbo of the tympanic membrane. The DHD successfully recreated ossicular chain movements across the frequencies of human hearing while demonstrating controllable magnitude. Moreover, the micro-actuator was validated in a short-term human clinical performance study where sound matching and complex audio waveforms were evaluated by a healthy subject.
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Schaap K, Christopher-De Vries Y, Cambron-Goulet É, Kromhout H. Work-related factors associated with occupational exposure to static magnetic stray fields from MRI scanners. Magn Reson Med 2015; 75:2141-55. [DOI: 10.1002/mrm.25720] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Kristel Schaap
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University; Utrecht the Netherlands
| | - Yvette Christopher-De Vries
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University; Utrecht the Netherlands
| | - Évelyne Cambron-Goulet
- Département des sciences de la santé communautaire; Université de Sherbrooke; Sherbrooke Canada
| | - Hans Kromhout
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University; Utrecht the Netherlands
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124
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Women are more strongly affected by dizziness in static magnetic fields of magnetic resonance imaging scanners. Neuroreport 2015; 25:1081-4. [PMID: 25089803 DOI: 10.1097/wnr.0000000000000225] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Increasing field strengths in MRI necessitate the examination of potential side effects. Previously reported results have been contradictory, possibly caused by imbalanced samples. We aimed to examine whether special groups of people are more prone to develop side effects that might have led to contradictory results in previous studies. We examined the occurrence of sensory side effects in static magnetic fields of MRI scanners of 1.5, 3, and 7 T and a mock scanner in 41 healthy participants. The contribution of field strength, sex, age, and attention to bodily processes, and stress hormone levels to the sensation of dizziness was examined in separate univariate analyses and in a joint analysis that included all variables. Field strength and sex were significant factors in the joint analysis (P=0.001), with women being more strongly affected than men by dizziness in higher static magnetic fields. This effect was not mediated by the other variables such as attention to bodily symptoms or stress hormones. Further research needs to elucidate the underlying factors of increased dizziness in women in static magnetic fields in MRI. We hypothesize that imbalanced samples of earlier studies might be one reason for previous contradictory results on the side effects of static magnetic fields.
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125
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Gorlin A, Hoxworth JM, Pavlicek W, Thunberg CA, Seamans D. Acute vertigo in an anesthesia provider during exposure to a 3T MRI scanner. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2015; 8:161-6. [PMID: 25792858 PMCID: PMC4362897 DOI: 10.2147/mder.s76474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Vertigo induced by exposure to the magnetic field of a magnetic resonance imaging (MRI) scanner is a well-known phenomenon within the radiology community but is not widely appreciated by other clinical specialists. Here, we describe a case of an anesthetist experiencing acute vertigo while providing sedation to a patient undergoing a 3 Tesla MRI scan. After discussing previous reports, and the evidence surrounding MRI-induced vertigo, we review potential etiologies that include the effects of both static and time-varying magnetic fields on the vestibular apparatus. We conclude our review by discussing the occupational standards that exist for MRI exposure and methods to minimize the risks of MRI-induced vertigo for clinicians working in the MRI environment.
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Affiliation(s)
- Andrew Gorlin
- Department of Anesthesiology, Mayo Clinic Arizona, Phoenix, AZ, USA
| | | | | | | | - David Seamans
- Department of Anesthesiology, Mayo Clinic Arizona, Phoenix, AZ, USA
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Wang L, Du H, Guo X, Wang X, Wang M, Wang Y, Wang M, Chen S, Wu L, Xu A. Developmental abnormality induced by strong static magnetic field inCaenorhabditis elegans. Bioelectromagnetics 2015; 36:178-89. [DOI: 10.1002/bem.21906] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 02/11/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Lei Wang
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Hua Du
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Xiaoying Guo
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Xinan Wang
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Meimei Wang
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Yichen Wang
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Min Wang
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Shaopeng Chen
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - Lijun Wu
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
| | - An Xu
- Key Laboratory of Ion Beam Bioengineering; Institute of Technical Biology and Agricultural Engineering; Hefei Institutes of Physical Science; Chinese Academy of Science; Hefei Anhui People's Republic of China
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127
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Vijayalaxmi, Fatahi M, Speck O. Magnetic resonance imaging (MRI): A review of genetic damage investigations. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 764:51-63. [PMID: 26041266 DOI: 10.1016/j.mrrev.2015.02.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/12/2015] [Accepted: 02/13/2015] [Indexed: 10/24/2022]
Abstract
Magnetic resonance imaging (MRI) is a powerful, non-invasive diagnostic medical imaging technique widely used to acquire detailed information about anatomy and function of different organs in the body, in both health and disease. It utilizes electromagnetic fields of three different frequency bands: static magnetic field (SMF), time-varying gradient magnetic fields (GMF) in the kHz range and pulsed radiofrequency fields (RF) in the MHz range. There have been some investigations examining the extent of genetic damage following exposure of bacterial and human cells to all three frequency bands of electromagnetic fields, as used during MRI: the rationale for these studies is the well documented evidence of positive correlation between significantly increased genetic damage and carcinogenesis. Overall, the published data were not sufficiently informative and useful because of the small sample size, inappropriate comparison of experimental groups, etc. Besides, when an increased damage was observed in MRI-exposed cells, the fate of such lesions was not further explored from multiple 'down-stream' events. This review provides: (i) information on the basic principles used in MRI technology, (ii) detailed experimental protocols, results and critical comments on the genetic damage investigations thus far conducted using MRI equipment and, (iii) a discussion on several gaps in knowledge in the current scientific literature on MRI. Comprehensive, international, multi-centered collaborative studies, using a common and widely used MRI exposure protocol (cardiac or brain scan) incorporating several genetic/epigenetic damage end-points as well as epidemiological investigations, in large number of individuals/patients are warranted to reduce and perhaps, eliminate uncertainties raised in genetic damage investigations in cells exposed in vitro and in vivo to MRI.
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Affiliation(s)
- Vijayalaxmi
- Department of Radiology, University of Texas Health Science Center, San Antonio, United States
| | - Mahsa Fatahi
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Disease (DZNE) Site, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany
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129
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Lahbib A, Ghodbane S, Maâroufi K, Louchami K, Sener A, Sakly M, Abdelmelek H. Vitamin D supplementation ameliorates hypoinsulinemia and hyperglycemia in static magnetic field-exposed rat. ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH 2015; 70:142-146. [PMID: 24965333 DOI: 10.1080/19338244.2013.828675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The purpose of this study is to evaluate the effects of vitamin D supplementation on glucose and lipid metabolism in static magnetic field (SMF)-exposed rats. Rats exposed to SMF (128 mT; 1 h/day) during 5 consecutive days showed an increase in plasma glucose level and a decrease in plasma insulin concentration. By contrast, the same treatment failed to alter body weight and plasmatic total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, and triglyceride levels. Interestingly, supplementation with vitamin D (1,600 IU/100 g, per os) corrected and restored glycemia and insulinemia in SMF-exposed rats. The same treatment had no effects on lipid metabolism.
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Affiliation(s)
- Aïda Lahbib
- a Laboratory of Integrative Physiology, Faculty of Sciences of Bizerte, Cathage University , Jarzouna , Tunisia
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130
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Tell RA, Hooper HC, Sias GG, Mezei G, Hung P, Kavet R. Electromagnetic Fields Associated with Commercial Solar Photovoltaic Electric Power Generating Facilities. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2015; 12:795-803. [PMID: 26023811 DOI: 10.1080/15459624.2015.1047021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The southwest region of the United States is expected to experience an expansion of commercial solar photovoltaic generation facilities over the next 25 years. A solar facility converts direct current generated by the solar panels to three-phase 60-Hz power that is fed to the grid. This conversion involves sequential processing of the direct current through an inverter that produces low-voltage three-phase power, which is stepped up to distribution voltage (∼12 kV) through a transformer. This study characterized magnetic and electric fields between the frequencies of 0 Hz and 3 GHz at two facilities operated by the Southern California Edison Company in Porterville, CA and San Bernardino, CA. Static magnetic fields were very small compared to exposure limits established by IEEE and ICNIRP. The highest 60-Hz magnetic fields were measured adjacent to transformers and inverters, and radiofrequency fields from 5-100 kHz were associated with the inverters. The fields measured complied in every case with IEEE controlled and ICNIRP occupational exposure limits. In all cases, electric fields were negligible compared to IEEE and ICNIRP limits across the spectrum measured and when compared to the FCC limits (≥0.3 MHz).
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Affiliation(s)
- R A Tell
- a Richard Tell Associates, Inc. , Mesquite , Nevada
| | - H C Hooper
- b Enertech Consultants , Campbell , California
| | - G G Sias
- c Southern California Edison Company , Rosemead , California
| | - G Mezei
- d Exponent, Menlo Park , California
| | - P Hung
- c Southern California Edison Company , Rosemead , California
| | - R Kavet
- e Electric Power Research Institute , Palo Alto , California
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131
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Friebe B, Wollrab A, Thormann M, Fischbach K, Ricke J, Grueschow M, Kropf S, Fischbach F, Speck O. Sensory perceptions of individuals exposed to the static field of a 7T MRI: A controlled blinded study. J Magn Reson Imaging 2014; 41:1675-81. [PMID: 25236353 DOI: 10.1002/jmri.24748] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/21/2014] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To determine the subjective experience of subjects undergoing 7T magnetic resonance imaging (MRI) compared to a mock scanner with no magnetic field. METHODS AND MATERIALS In all, 44 healthy subjects were exposed to both the B0 field of a 7T whole-body MRI and a realistic mock scanner with no magnetic field. Subjects were blinded to the actual field strength and no scanning was performed. After exposure, subjects rated their experience of potential sensory perceptions. RESULTS The most frequently observed side effect was vertigo while entering the gantry, which was reported by 38.6% (n = 17). Other frequent side effects were the appearance of phosphenes (18.2%, n = 8), thermal heat sensation (15.9%), unsteady gait after exposure (13.6%, n = 6), and dizziness (13.6%). All side effects were reported significantly more often after 7T exposure. Nine subjects (20.5%) did not report any sensory perceptions at all, ie, neither in the 7T scanner nor in the mock scanner. CONCLUSION Light, acute, and transient sensory perceptions can occur in subjects undergoing ultrahighfield MRI, of which vertigo seems to be the most frequently reported. Possible psychological effects might contribute to the emergence of such sensory perceptions, as some subjects also reported them to appear in a realistic mock scanner with no magnetic field.
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Affiliation(s)
- Björn Friebe
- Department of Radiology and Nuclear Medicine, Otto-von-Guericke University Magdeburg, Germany
| | - Astrid Wollrab
- Department of Biomedical Magnetic Resonance (BMMR), Division Experimental Physics, Faculty of Physics, Otto-von-Guericke University Magdeburg, Germany
| | - Markus Thormann
- Department of Radiology and Nuclear Medicine, Otto-von-Guericke University Magdeburg, Germany
| | - Katharina Fischbach
- Department of Radiology and Nuclear Medicine, Otto-von-Guericke University Magdeburg, Germany
| | - Jens Ricke
- Department of Radiology and Nuclear Medicine, Otto-von-Guericke University Magdeburg, Germany
| | | | - Siegfried Kropf
- Institute for Biometrics and Biomedical Informatics, Otto-von-Guericke University Magdeburg, Germany
| | - Frank Fischbach
- Department of Radiology and Nuclear Medicine, Otto-von-Guericke University Magdeburg, Germany
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance (BMMR), Division Experimental Physics, Faculty of Physics, Otto-von-Guericke University Magdeburg, Germany
- Leibniz Institute for Neurobiology, Magdeburg, Germany
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Exposition professionnelle aux champs électromagnétiques et dérèglement d’une valve de dérivation ventriculo-péritonéale : à propos d’un cas. ARCH MAL PROF ENVIRO 2014. [DOI: 10.1016/j.admp.2014.03.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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134
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Schaap K, Christopher-De Vries Y, Crozier S, De Vocht F, Kromhout H. Exposure to static and time-varying magnetic fields from working in the static magnetic stray fields of MRI scanners: a comprehensive survey in the Netherlands. ACTA ACUST UNITED AC 2014; 58:1094-110. [PMID: 25139484 DOI: 10.1093/annhyg/meu057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Clinical and research staff who work around magnetic resonance imaging (MRI) scanners are exposed to the static magnetic stray fields of these scanners. Although the past decade has seen strong developments in the assessment of occupational exposure to electromagnetic fields from MRI scanners, there is insufficient insight into the exposure variability that characterizes routine MRI work practice. However, this is an essential component of risk assessment and epidemiological studies. This paper describes the results of a measurement survey of shift-based personal exposure to static magnetic fields (SMF) (B) and motion-induced time-varying magnetic fields (dB/dt) among workers at 15 MRI facilities in the Netherlands. With the use of portable magnetic field dosimeters, >400 full-shift and partial shift exposure measurements were collected among various jobs involved in clinical and research MRI. Various full-shift exposure metrics for B and motion-induced dB/dt exposure were calculated from the measurements, including instantaneous peak exposure and time-weighted average (TWA) exposures. We found strong correlations between levels of static (B) and time-varying (dB/dt) exposure (r = 0.88-0.92) and between different metrics (i.e. peak exposure, TWA exposure) to express full-shift exposure (r = 0.69-0.78). On average, participants were exposed to MRI-related SMFs during only 3.7% of their work shift. Average and peak B and dB/dt exposure levels during the work inside the MRI scanner room were highest among technical staff, research staff, and radiographers. Average and peak B exposure levels were lowest among cleaners, while dB/dt levels were lowest among anaesthesiology staff. Although modest exposure variability between workplaces and occupations was observed, variation between individuals of the same occupation was substantial, especially among research staff. This relatively large variability between workers with the same job suggests that exposure classification based solely on job title may not be an optimal grouping strategy for epidemiological purposes.
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Affiliation(s)
- Kristel Schaap
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht 3508 TD, Netherlands;
| | - Yvette Christopher-De Vries
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht 3508 TD, Netherlands
| | - Stuart Crozier
- The School of Information Technology and Electrical Engineering, University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Frank De Vocht
- School of Social and Community Medicine, University of Bristol, Bristol BS8 2PS, UK
| | - Hans Kromhout
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht 3508 TD, Netherlands;
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135
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Lahbib A, Ghodbane S, Sakly M, Abdelmelek H. Vitamins and glucose metabolism: The role of static magnetic fields. Int J Radiat Biol 2014; 90:1240-5. [DOI: 10.3109/09553002.2014.930537] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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136
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137
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Israel M, Zaryabova V, Ivanova M. Electromagnetic field occupational exposure: non-thermal vs. thermal effects. Electromagn Biol Med 2014; 32:145-54. [PMID: 23675617 DOI: 10.3109/15368378.2013.776349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There are a variety of definitions for "non-thermal effects" included in different international standards. They start by the simple description that they are "effects of electromagnetic energy on a body that are not heat-related effects", passing through the very general definition related to low-level effects: "biological effects ascribed to exposure to low-level electric, magnetic and electromagnetic fields, i.e. at or below the corresponding dosimetric reference levels in the frequency range covered in this standard (0 Hz-300 GHz)", and going to the concrete definition of "the stimulation of muscles, nerves, or sensory organs, vertigo or phosfenes". Here, we discuss what kind of effect does the non-thermal one has on human body and give data of measurements in different occupations with low-frequency sources of electromagnetic field such as electric power distribution systems, transformers, MRI systems and : video display units (VDUs), whereas thermal effects should not be expected. In some of these workplaces, values above the exposure limits could be found, nevertheless that they are in the term "non-thermal effects" on human body. Examples are workplaces in MRI, also in some power plants. Here, we will not comment on non-thermal effects as a result of RF or microwave exposure because there are not proven evidence about the existance of such effects and mechanisms for them are not clear.
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Affiliation(s)
- M Israel
- National Centre of Public Health and Analysis, Sofia, Bulgaria.
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138
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Karpowicz J, Gryz K. The pattern of exposure to static magnetic field of nurses involved in activities related to contrast administration into patients diagnosed in 1.5 T MRI scanners. Electromagn Biol Med 2014; 32:182-91. [PMID: 23675621 DOI: 10.3109/15368378.2013.776428] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Static magnetic fields (SMFs) and time-varying electromagnetic fields exposure is necessary to obtain the diagnostic information regarding the structure of patient's tissues, by the use of magnetic resonance imaging (MRI) scanners. A diagnostic procedure may also include the administration of pharmaceuticals called contrast, which are to be applied to a patient during the examination. The nurses involved in administering contrast into a patient during the pause in examination are approaching permanently active magnets of MRI scanners and are exposed to SMF. There were performed measurements of spatial distribution of SMF in the vicinity of MRI magnets and parameters of personal exposure of nurses (i.e. individual exposimetric profiles of variability in time of SMF affecting the nurse who is performing tasks in the vicinity of magnet, characterized by statistical parameters of recorded magnetic flux density affecting the nurse). The SMF exposure in the vicinity of various MRI magnets depends on both magnetic flux density of the main field B 0 (applicable to a patient) and the construction of the scanner, but the most important factor determining the workers' exposure is the work practice. In the course of a patient's routine examination in scanners of B₀ = 1.5 T, the nurses are present over ∼0.4-2.9 min in SMF exceeding 0.03% of B₀ (i.e. 0.5 mT), but only sometimes they are present in SMF exceeding 5% of B 0 (i.e. 75 mT). When patients need more attention because of their health status/condition, the nurses' exposure may be significantly longer--it may even exceed 10 min and 30% of B 0 (i.e. 500 mT). We have found that the level of exposure of nurses to SMF may vary from < 5% of the main field (a median value: 0.5-1.5%; inter-quartile range: 0.04-8.8%; max value: 1.3-12% of B₀) when a patient is moved from the magnets bore before contrast administration, up to the main field level (B₀) when a patient stays in the magnets bore and nurse is crawling into the bore.
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Affiliation(s)
- Jolanta Karpowicz
- Laboratory of Electromagnetic Hazards, Central Institute for Labour Protection-National Research Institute-CIOP-PIB, Warszawa, Poland.
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139
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Gürler HŞ, Bilgici B, Akar AK, Tomak L, Bedir A. Increased DNA oxidation (8-OHdG) and protein oxidation (AOPP) by low level electromagnetic field (2.45 GHz) in rat brain and protective effect of garlic. Int J Radiat Biol 2014; 90:892-6. [DOI: 10.3109/09553002.2014.922717] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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140
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Leitgeb N. Limiting electric fields of HVDC overhead power lines. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2014; 53:461-468. [PMID: 24573710 DOI: 10.1007/s00411-014-0520-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 02/02/2014] [Indexed: 06/03/2023]
Abstract
As a consequence of the increased use of renewable energy and the now long distances between energy generation and consumption, in Europe, electric power transfer by high-voltage (HV) direct current (DC) overhead power lines gains increasing importance. Thousands of kilometers of them are going to be built within the next years. However, existing guidelines and regulations do not yet contain recommendations to limit static electric fields, which are one of the most important criteria for HVDC overhead power lines in terms of tower design, span width and ground clearance. Based on theoretical and experimental data, in this article, static electric fields associated with adverse health effects are analysed and various criteria are derived for limiting static electric field strengths.
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Affiliation(s)
- N Leitgeb
- Institute of Health Care Engineering with European Notified Body of Medical Devices, Graz University of Technology, Kopernikusgasse 24, 8010, Graz, Austria,
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141
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Csillag A, Kumar BV, Szabó K, Szilasi M, Papp Z, Szilasi ME, Pázmándi K, Boldogh I, Rajnavölgyi É, Bácsi A, László JF. Exposure to inhomogeneous static magnetic field beneficially affects allergic inflammation in a murine model. J R Soc Interface 2014; 11:20140097. [PMID: 24647908 DOI: 10.1098/rsif.2014.0097] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Previous observations suggest that static magnetic field (SMF)-exposure acts on living organisms partly through reactive oxygen species (ROS) reactions. In this study, we aimed to define the impact of SMF-exposure on ragweed pollen extract (RWPE)-induced allergic inflammation closely associated with oxidative stress. Inhomogeneous SMF was generated with an apparatus validated previously providing a peak-to-peak magnetic induction of the dominant SMF component 389 mT by 39 T m(-1) lateral gradient in the in vivo and in vitro experiments, and 192 mT by 19 T m(-1) in the human study at the 3 mm target distance. Effects of SMF-exposure were studied in a murine model of allergic inflammation and also in human provoked skin allergy. We found that even a single 30-min exposure of mice to SMF immediately following intranasal RWPE challenge significantly lowered the increase in the total antioxidant capacity of the airways and decreased allergic inflammation. Repeated (on 3 consecutive days) or prolonged (60 min) exposure to SMF after RWPE challenge decreased the severity of allergic responses more efficiently than a single 30-min treatment. SMF-exposure did not alter ROS production by RWPE under cell-free conditions, while diminished RWPE-induced increase in the ROS levels in A549 epithelial cells. Results of the human skin prick tests indicated that SMF-exposure had no significant direct effect on provoked mast cell degranulation. The observed beneficial effects of SMF are likely owing to the mobilization of cellular ROS-eliminating mechanisms rather than direct modulation of ROS production by pollen NAD(P)H oxidases.
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Affiliation(s)
- Anikó Csillag
- Department of Immunology, Faculty of Medicine, University of Debrecen, , 98 Nagyerdei Boulevard, Debrecen 4012, Hungary
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142
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van Nierop LE, Christopher-de Vries Y, Slottje P, Kromhout H. Does assessment of personal exposure matter during experimental neurocognitive testing in MRI-related magnetic fields? Magn Reson Med 2014; 73:765-72. [PMID: 24610803 DOI: 10.1002/mrm.25173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/24/2013] [Accepted: 01/17/2014] [Indexed: 11/06/2022]
Abstract
PURPOSE To determine whether the use of quantitative personal exposure measurements in experimental research would result in better estimates of the associations between static and time-varying magnetic field exposure and neurocognitive test performance than when exposure categories were based solely on distance to the magnetic field source. METHODS In our original analysis, based on distance to the magnet of a 7 T MRI scanner, an effect of exposure to static magnetic fields was observed. We performed a sensitivity analysis of test performance on a reaction task and line bisection task with different exposure measures that were derived from personal real-time measurements. RESULTS The exposure measures were highly comparable, and almost all models resulted in significant associations between exposure to time-varying magnetic fields within a static magnetic field and performance on a reaction and line bisection task. CONCLUSION In a controlled experimental setup, distance to the bore is a good proxy for personal exposure when placing subjects at fixed positions with standardized head movements in the magnetic stray fields of a 7 T MRI. Use of a magnetic field dosimeter is, however, important for estimating quantitative exposure response associations.
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Affiliation(s)
- Lotte E van Nierop
- Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht, The Netherlands
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143
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Guidelines for limiting exposure to electric fields induced by movement of the human body in a static magnetic field and by time-varying magnetic fields below 1 Hz. HEALTH PHYSICS 2014; 106:418-425. [PMID: 25208018 DOI: 10.1097/hp.0b013e31829e5580] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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144
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Stam R. The revised electromagnetic fields directive and worker exposure in environments with high magnetic flux densities. ANNALS OF OCCUPATIONAL HYGIENE 2014; 58:529-41. [PMID: 24557933 DOI: 10.1093/annhyg/meu010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Some of the strongest electromagnetic fields (EMF) are found in the workplace. A European Directive sets limits to workers' exposure to EMF. This review summarizes its origin and contents and compares magnetic field exposure levels in high-risk workplaces with the limits set in the revised Directive. Pubmed, Scopus, grey literature databases, and websites of organizations involved in occupational exposure measurements were searched. The focus was on EMF with frequencies up to 10 MHz, which can cause stimulation of the nervous system. Selected studies had to provide individual maximum exposure levels at the workplace, either in terms of the external magnetic field strength or flux density or as induced electric field strength or current density. Indicative action levels and the corresponding exposure limit values for magnetic fields in the revised European Directive will be higher than those in the previous version. Nevertheless, magnetic flux densities in excess of the action levels for peripheral nerve stimulation are reported for workers involved in welding, induction heating, transcranial magnetic stimulation, and magnetic resonance imaging (MRI). The corresponding health effects exposure limit values for the electric fields in the worker's body can be exceeded for welding and MRI, but calculations for induction heating and transcranial magnetic stimulation are lacking. Since the revised European Directive conditionally exempts MRI-related activities from the exposure limits, measures to reduce exposure may be necessary for welding, induction heating, and transcranial nerve stimulation. Since such measures can be complicated, there is a clear need for exposure databases for different workplace scenarios with significant EMF exposure and guidance on good practices.
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Affiliation(s)
- Rianne Stam
- Centre for Sustainability, Environment and Health, National Institute for Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands
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145
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White MJ, Thornton JS, Hawkes DJ, Hill DL, Kitchen N, Mancini L, McEvoy AW, Razavi R, Wilson S, Yousry T, Keevil SF. Design, Operation, and Safety of Single-Room Interventional MRI Suites: Practical Experience From Two Centers. J Magn Reson Imaging 2014; 41:34-43. [DOI: 10.1002/jmri.24577] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 01/10/2014] [Indexed: 11/06/2022] Open
Affiliation(s)
- Mark J. White
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
- UCL Institute of Neurology; Queen Square, London UK
| | - John S. Thornton
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
- UCL Institute of Neurology; Queen Square, London UK
| | | | | | - Neil Kitchen
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
- UCL Institute of Neurology; Queen Square, London UK
| | - Laura Mancini
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
- UCL Institute of Neurology; Queen Square, London UK
| | - Andrew W. McEvoy
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
- UCL Institute of Neurology; Queen Square, London UK
| | | | - Sally Wilson
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
| | - Tarek Yousry
- National Hospital for Neurology and Neurosurgery; Queen Square, London UK
- UCL Institute of Neurology; Queen Square, London UK
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146
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Møllerløkken OJ. Elektromagnetiske felt i medisinen – behov for risikovurdering? TIDSSKRIFT FOR DEN NORSKE LEGEFORENING 2014; 134:393. [DOI: 10.4045/tidsskr.13.1619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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147
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Carrio I, Ros P. Risks and Safety Aspects of MR-PET. PET/MRI 2014. [PMCID: PMC7122917 DOI: 10.1007/978-3-642-40692-8_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The introduction of MR-PET systems into medical practice not only may lead to a gain in clinical diagnosis as compared to PET-CT imaging due to the superior soft tissue contrast of the MR technology but can also substantially reduce exposure of patients to ionizing radiation. On the other hand, there are also risks and health effects associated with the use of diagnostic MR devices that have to be considered carefully. In this chapter, the biophysical and biological aspects relevant for the assessment of health effects related to the use of ionizing radiation in PET and (electro)magnetic fields in MR are summarized. On this basis, the current safety standards will be presented – which, however, do not address the possibility of synergistic effects of ionizing radiation and (electro)magnetic fields. In the light of the developing MR-PET technology, it is of utmost importance to investigate this aspect in more detail for exposure levels that will occur at MR-PET systems. Finally, some considerations concerning the justification and optimization of MR-PET examination will be made.
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Affiliation(s)
- Ignasi Carrio
- Depto. Medicina Nuclear, Autonomous University of Barcelona Hospital Sant Pau, Barcelona, Spain
| | - Pablo Ros
- Department of Radiology, University Hospitals Case Medical Center, Cleveland, Ohio USA
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148
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Acri G, Testagrossa B, Causa F, Tripepi MG, Vermiglio G, Novario R, Pozzi L, Quadrelli G. Evaluation of occupational exposure in magnetic resonance sites. Radiol Med 2013; 119:208-13. [PMID: 24337753 DOI: 10.1007/s11547-013-0324-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/22/2012] [Indexed: 11/30/2022]
Abstract
PURPOSE In an attempt to evaluate the exposure level of magnetic resonance imaging (MRI) workers to static magnetic fields, the isotropic magnetic flux density values were integrated over time to produce the cumulative exposure. To protect occupational staff a further precautionary step is proposed by introducing a weighting function incorporating the limits imposed by the Italian legislation. The results obtained should be reported, at the end of each working day, on a special dose card, in order to record each worker's exposure to the static magnetic field. Moreover, this dose card could be an important tool if long-term effects occur because it provides a complete history of the occupational exposure in an MRI site. MATERIALS AND METHODS To conduct measurements, three Hall-sensor probes were used. The consistency of experimental data, tools and methodologies used was evaluated by performing the Kruskal-Wallis test. Finally, the weighted magnitude of the magnetic flux density was integrated over time to obtain global exposure. RESULTS Measurements were performed on different MRI scanners ranging from 0.25 up to 3.0 T. The results obtained were compared with the 200 mT·h, which represents the upper limit of the Italian regulation. In no case was the 200 mT·h per day exposure exceeded: however, when the strength of the magnetic field was >200 mT the weighted function overestimated the exposure, so that it represents a highly precautionary measure taking into account possible acute and long-term effects. In addition, from the data recorded during patient positioning operations by MRI staff the dB/dt curve was obtained. CONCLUSIONS The areas obtained from the integral of the weighted static magnetic field strength over time can be indicative of the global exposure of the occupational staff. These values should be reported on a special dose card that could be considered as an important tool if long-term effects occur because it provides a complete history of the occupational exposure in an MRI site.
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Affiliation(s)
- Giuseppe Acri
- S.A.S.T.A.S Department-Section of Protezionistica A.S.S.I, University of Messina, Viale Gazzi-Policlinico Universitario, Torre Biologica, 98125, Messina, Italy,
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149
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Zilberti L, Chiampi M. A numerical survey of motion-induced electric fields experienced by MRI operators. HEALTH PHYSICS 2013; 105:498-511. [PMID: 24162054 DOI: 10.1097/hp.0b013e31829b4aac] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This paper deals with the electric field generated inside the bodies of people moving in proximity to magnetic resonance scanners. Different types of scanners (tubular and open) and various kinds of movements (translation, rotation, and revolution) are analyzed, considering the homogeneous human model proposed in some technical Standards. The computations are performed through the Boundary Element Method, adopting a reference frame attached to the body, which significantly reduces the computational burden. The induced electric fields are evaluated in terms of both spatial distributions and local time evolutions. The possibility of limiting the study to the head without affecting the accuracy of the results is also investigated. Finally, a first attempt to quantify the transient effect of charge separation is proposed.
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Affiliation(s)
- Luca Zilberti
- *Istituto Nazionale di Ricerca Metrologica, Torino, Italy; †Dipartimento Energia, Politecnico di Torino, Italy
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150
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Guibelalde del Castillo E. [Patient exposure to electromagnetic fields in magnetic resonance scanners: a review]. RADIOLOGIA 2013; 55 Suppl 2:2-8. [PMID: 24246885 DOI: 10.1016/j.rx.2013.09.003] [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: 03/19/2013] [Revised: 09/11/2013] [Accepted: 09/21/2013] [Indexed: 11/16/2022]
Abstract
The use of non-ionizing electromagnetic fields in the low frequency end of the electromagnetic spectrum and static fields, radiofrequencies (RF), and microwaves is fundamental both in modern communication systems and in diagnostic medical imaging techniques like magnetic resonance imaging (MRI). The proliferation of these applications in recent decades has led to intense activity in developing regulations to guarantee their safety and to the establishment of guidelines and legal recommendations for the public, workers, and patients. In April 2012 it was foreseen that the European Parliament and Council would approve and publish a directive on the minimum health and safety requirements regarding the exposure of workers to the risks arising from electromagnetic fields, which would modify Directive 2004/40/EC. New studies related to the exposure to electromagnetic radiation and its impact on health published in recent years have led to a new postponement, and it is now foreseen that the directive will come into effect in October 2013. One of the most noteworthy aspects of the new version of the directive is the exclusion of the limits of occupational exposure to electromagnetic fields in the clinical use of MRI. In exchange for this exception, physicians and experts in protection against non-ionizing radiation are asked to make additional efforts to train workers exposed to non-ionizing radiation and to establish mechanisms to guarantee the correct application of non-ionizing electromagnetic fields in patients, along similar lines to the principles of justification and optimization established for ionizing radiation. On the basis of the most recently published studies, this article reviews some safety-related aspects to take into account when examining patients with MRI with high magnetic fields.
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Affiliation(s)
- E Guibelalde del Castillo
- Departamento de Radiología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, España.
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