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  • 1. de Vocht, Frank
    et al.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    van Nierop, Lotte E
    Slottje, Pauline
    Kromhout, Hans
    Health effects and safety of magnetic resonance imaging2012Ingår i: Journal of medical systems, ISSN 0148-5598, E-ISSN 1573-689X, Vol. 36, nr 3, s. 1779-1780Artikel i tidskrift (Refereegranskat)
  • 2.
    Frankel, Jennifer
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Olsrud, Johan
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    EMF exposure variation among MRI sequences from pediatric examination protocols2019Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 40, nr 1, s. 3-15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The magnetic resonance imaging (MRI) exposure environment is unique due to the mixture and intensity of magnetic fields involved. Current safety regulations are based on well-known acute effects of heating and neuroexcitation while the scientific grounds for possible long-term effects from MRI exposure are lacking. Epidemiological research requires careful exposure characterization, and as a first step toward improved exposure assessment we set out to characterize the MRI-patient exposure environment. Seven MRI sequences were run on a 3-Tesla scanner while the radiofrequency and gradient magnetic fields were measured inside the scanner bore. The sequences were compared in terms of 14 different exposure parameters. To study within-sequence variability, we varied sequence settings such as flip angle and slice thickness one at a time, to determine if they had any impact on exposure endpoints. There were significant differences between two or more sequences for all fourteen exposure parameters. Within-sequence differences were up to 60% of the corresponding between-sequence differences, and a 5-8 fold exposure increase was caused by variations in flip angle, slice spacing, and field of view. MRI exposure is therefore not only sequence-specific but also patient- and examination occurrence-specific, a complexity that requires careful consideration for an MRI exposure assessment in epidemiological studies to be meaningful. 

  • 3.
    Frankel, Jennifer
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Assessing exposures to Magnetic resonance imaging's complex Mixture of Magnetic Fields for In Vivo, In Vitro, and epidemiologic studies of Health effects for staff and Patients2018Ingår i: Frontiers In Public Health, ISSN 2296-2565, Vol. 6, artikel-id 66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A complex mixture of electromagnetic fields is used in magnetic resonance imaging (MRI): static, low-frequency, and radio frequency magnetic fields. Commonly, the static magnetic field ranges from one to three Tesla. The low-frequency field can reach several millitesla and with a time derivative of the order of some Tesla per second. The radiofrequency (RF) field has a magnitude in the microtesla range giving rise to specific absorption rate values of a few Watts per kilogram. Very little attention has been paid to the case where there is a combined exposure to several different fields at the same time. Some studies have shown genotoxic effects in cells after exposure to an MRI scan while others have not demonstrated any effects. A typical MRI exam includes muliple imaging sequences of varying length and intensity, to produce different types of images. Each sequence is designed with a particular purpose in mind, so one sequence can, for example, be optimized for clearly showing fat water contrast, while another is optimized for high-resolution detail. It is of the utmost importance that future experimental studies give a thorough description of the exposure they are using, and not just a statement such as "An ordinary MRI sequence was used." Even if the sequence is specified, it can differ substantially between manufacturers on, e.g., RF pulse height, width, and duty cycle. In the latest SCENIHR opinion, it is stated that there is very little information regarding the health effects of occupational exposure to MRI fields, and long-term prospective or retrospective cohort studies on workers are recommended as a high priority. They also state that MRI is increasingly used in pediatric diagnostic imaging, and a cohort study into the effects of MRI exposure on children is recommended as a high priority. For the exposure assessment in epidemiological studies, there is a clear difference between patients and staff and further work is needed on this. Studies that explore the possible differences between MRI scan sequences and compare them in terms of exposure level are warranted.

  • 4. Hansson, Boel
    et al.
    Höglund, Peter
    Markenroth Bloch, Karin
    Nilsson, Markus
    Olsrud, Johan
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Björkman-Burtscher, Isabella M.
    Short-term effects experienced during examinations in an actively shielded 7 T MR2019Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 40, nr 4, s. 234-249Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of this study was to evaluate occurrence and strength of short‐term effects experienced by study participants in an actively shielded (AS) 7 tesla (7 T) magnetic resonance (MR) scanner, to compare results with earlier reports on passively shielded (PS) 7 T MR scanners, and to outline possible healthcare strategies to improve patient compliance. Study participants (n = 124) completed a web‐based questionnaire directly after being examined in an AS 7 T MR (n = 154 examinations). Most frequently experienced short‐term effects were dizziness (84%) and inconsistent movement (70%), especially while moving into or out of the magnet. Peripheral nerve stimulation (PNS)—twitching—was experienced in 67% of research examinations and showed a dependence between strength of twitches and recorded predicted PNS values. Of the participants, 74% experienced noise levels as acceptable and the majority experienced body and room temperature as comfortable. Of the study participants, 95% felt well‐informed and felt they had had good contact with the staff before the examination. Willingness to undergo a future 7 T examination was high (>90%). Our study concludes short‐term effects are often experienced during examinations in an AS 7 T MR, leaving room for improvement in nursing care strategies to increase patient compliance.

  • 5.
    Hansson Mild, Kjell
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hand, Jeff
    Hietanen, Maila
    Gowland, Penny
    Karpowicz, Jolanta
    Keevil, Stephen
    Lagroye, Isabelle
    van Rongen, Eric
    Scarfi, Maria Rosaria
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Exposure classification of MRI workers in epidemiological studies2013Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 34, nr 1, s. 81-84Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We estimate that there are about 100,000 workers from different disciplines, such as radiographers, nurses, anesthetists, technicians, engineers, etc., who can be exposed to substantial electromagnetic fields (compared to normal background levels) around magnetic resonance imaging (MRI) scanners. There is a need for well-designed epidemiological studies of MRI workers but since the exposure from MRI equipment is a very complex mixture of static magnetic fields, switched gradient magnetic fields, and radiofrequency electromagnetic fields (RF EMF), it is necessary to discuss how to assess the exposure in epidemiological studies. As an alternative to the use of job title as a proxy of exposure, we propose an exposure categorization for the different professions working with MRI equipment. Specifically, we propose defining exposure in three categories, depending on whether people are exposed to only the static field, to the static plus switched gradient fields or to the static plus switched gradient plus RF fields, as a basis for exposure assessment in epidemiological studies.

  • 6.
    Hansson Mild, Kjell
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Lundström, Ronnie
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Non-Ionizing Radiation in Swedish Health CareExposure and Safety Aspects2019Ingår i: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, nr 7, artikel-id 1186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The main aim of the study was to identify and describe methods using non-ionizing radiation (NIR) such as electromagnetic fields (EMF) and optical radiation in Swedish health care. By examining anticipated exposure levels and by identifying possible health hazards we also aimed to recognize knowledge gaps in the field. NIR is mainly used in health care for diagnosis and therapy. Three applications were identified where acute effects cannot be ruled out: magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS) and electrosurgery. When using optical radiation, such as class 3 and 4 lasers for therapy or surgical procedures and ultra-violet light for therapy, acute effects such as unintentional burns, photo reactions, erythema and effects on the eyes need to be avoided. There is a need for more knowledge regarding long-term effects of MRI as well as on the combination of different NIR exposures. Based on literature and after consulting staff we conclude that the health care professionals' knowledge about the risks and safety measures should be improved and that there is a need for clear, evidence-based information from reliable sources, and it should be obvious to the user which source to address.

  • 7.
    Hansson Mild, Kjell
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Occupational exposure in wireless communication2009Ingår i: Advances in electromagnetic fields in living systems: Vol 5, Health effects of cell phone radiation / [ed] James C Lin, Heidelberg: Springer-Verlag New York, 2009, s. 199-219Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Today we are exposed to electromagnetic fields from the use of wireless communication devices almost everywhere. However, occupational exposure where there is a possibility to exceed the international guidelines occurs only in work very near mobile phone base stations, and this exposure can easily be dealt with in practice in the form of instructions and administrative measures. All other devices produce exposure well below present guidelines. This low-level exposure has been discussed from a health perspective, and in this paper the exposure from sources such as mobile phones, cordless phones, WiMax, WLAN and base station antennas is discussed. The problem of exposure assessment for epidemiological studies is also dealt with in a general manner.

  • 8.
    Hansson Mild, Kjell
    et al.
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Radiofysik.
    Wilén, Jonna
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Radiofysik.
    Mattsson, Mats-Olof
    Simko, Myrtill
    Background ELF magnetic fields in incubators: A factor of importance in cell culture work.2009Ingår i: Cell biology international, ISSN 1095-8355, Vol. 33, s. 755-757Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Extremely low frequency (ELF) magnetic fields in cell culture incubators have been measured. Values of the order of tens of muT were found which is in sharp contrast to the values found in our normal environment (0.05-0.1muT). There are numerous examples of biological effects found after exposure to MF at these levels, such as changes in gene expression, blocked cell differentiation, inhibition of the effect of tamoxifen, effects on chick embryo development, etc. We therefore recommend that people working with cell culture incubators check for the background magnetic field and take this into account in performing their experiments, since this could be an unrecognised factor of importance contributing to the variability in the results from work with cell cultures.

  • 9.
    Johansson, Amanda
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Forsgren, Sture
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Stenberg, Berndt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Dermatologi och venereologi.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Kalezic, Nebojsa
    Sandström, Monica
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    No effect of mobile phone-like RF exposure on patients with atopic dermatitis.2008Ingår i: Bioelectromagnetics, ISSN 1521-186X, Vol. 29, nr 5, s. 353-362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the effect of exposure to a mobile phone-like radiofrequency (RF) electromagnetic field on people with atopic dermatitis (AD). Fifteen subjects with AD were recruited and matched with 15 controls without AD. The subjects were exposed for 30 min to an RF field at 1 W/kg via an indoor base station antenna attached to a 900 MHz GSM mobile phone. Blood samples for ELISA analysis of the concentration of substance P (SP), tumor necrosis factor receptor 1 (TNF R1), and brain derived neurotrophic factor (BDNF) in serum were drawn before and after the provocation (exposure/sham). Baseline heart rate and heart rate variability, local blood flow, and electrodermal activity were also recorded. No significant differences between the subject groups were found for baseline neurophysiological data. The cases displayed a serum concentration of TNF R1 significantly higher than the control subjects and a significantly lower serum concentration of BDNF in the baseline condition. For SP there was no difference between groups. However, no effects related to RF exposure condition were encountered for any of the measured substances. As to symptoms, a possible correlation with exposure could not be evaluated, due to too few symptom reports. The result of the study does not support the hypothesis of an effect of mobile phone-like RF exposure on serum levels of SP, TNF R1, and BDNF in persons with AD.

  • 10.
    Mild, Kjell Hansson
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Friberg, Stefan
    Frankel, Jennifer
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Wilen, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Exposure to the magnetic field from an induction loop pad for a hearing aid system2017Ingår i: International Journal of Occupational Safety and Ergonomics, ISSN 1080-3548, E-ISSN 2376-9130, Vol. 23, nr 1, s. 143-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As a case study we have measured the magnetic field from an induction loop pad designed for hearing aid assistance. The magnitude of the field was high, although well below international guidelines. We recorded values up to 70% of the recommended standard in some instances. However, in view of the many reports indicating health effects of low-level exposure, we recommend that the precautionary principle is applied when such pads are given to people who might be especially vulnerable, such as children, pregnant women and women on breast cancer medication.

  • 11.
    Sandström, Monica
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Johansson, Amanda
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Karlsson, Berndt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Arbetare med medicinska implantat: vägledning vid återgång i arbete i miljöer som innebär exponering för elektromagnetiska fält2009Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Allt fler personer bär idag någon form av medicinska implantat. Det kan varaaktiva implantat som pacemakers eller passiva som exempelvis knä eller höftprotes.Återgång till arbetsliv är normalt inget problem, men i vissa yrken kandet kompliceras av den miljö som arbetaren vistas i. Exponering för elektromagnetiskafält, från statiska fält upp till och med mikrovågsområdet, kan påverkasåväl aktiva som passiva implantat. Felfunktion hos implantatet, elektrostimuleringav närliggande nerver och muskler och upphettning av närliggande vävnadär exempel på sådan oönskad påverkan.

    Det ställs idag höga krav på störtålighet hos implanterbar medicinteknisk utrustning.Trots detta finns det en rad situationer där oönskad påverkan kan ske.Individfaktorer, arbetssätt och inte minst att varje utrustning kan sägas varaunik, bidrar till svårigheten att ge generella råd.

    I den riskbedömning som arbetsgivaren är ålagd att utföra enligt arbetsmiljölagenska hänsyn tas till personer med speciella behov, exempelvis personermed olika typer av implantat.

    Vilka som är involverade i riskbedömningen och hur omfattande den bör varaberor på vilken typ av implantat och vilken typ av arbete det gäller. Väsentligtär att såväl medicinsk som teknisk kompetens bör delta i riskbedömningen. Vadgäller störtåligheten för ett specifikt implantat så är tillverkarna av implantatende som bäst kan bistå med information. Riskbedömningen bör inkludera följandemoment:

    Typ av implantat och dess känslighet för yttre påverkan samt medicinskakonsekvenser av felfunktion;Identifiera möjliga källor för påverkan på arbetsplatsen;Sammanställning och analys av insamlad data;Slutsatser och råd om hur arbetet lämpligast ska utformas och utföras;Uppföljande kontroll, speciellt viktigt vid ändrade arbetsuppgifter ellerinförande av nya moment.

  • 12. Straume, Aksel
    et al.
    Johnsson, Anders
    Oftedal, Gunnhild
    Wilén, Jonna
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Radiofysik.
    Frequency spectra from current vs. magnetic flux density measurements for mobile phones and other electrical appliances2007Ingår i: Health Phys, ISSN 0017-9078, Vol. 93, nr 4, s. 279-287Artikel i tidskrift (Refereegranskat)
  • 13.
    Sundström, Henrik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Wilen, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Measurements of the Ripple Effect and Geometric Distribution of Switched Gradient Fields Inside a Magnetic Resonance Scanner2015Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 36, nr 2, s. 162-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Knowledge of patient exposure during magnetic resonance imaging (MRI) procedures is limited, and the need for such knowledge has been demonstrated in recent in vitro and in vivo studies of the genotoxic effects of MRI. This study focuses on the dB/dt of the switched gradient field (SGF) and its geometric distribution. These values were characterized by measuring the peak dB/dt generated by a programmed gradient current of alternating triangles inside a 1.5T MR scanner. The maximum dB/dt exposure to the gradient field was 6-14T/s, and this occurred at the edges of the field of view (FOV) 20-25cm from the isocenter in the longitudinal direction. The dB/dt exposure dropped off to roughly half the maximum (3-7T/s) at the edge of the bore. It was found that the dB/dt of the SGF was distorted by a 200kHz ripple arising from the amplifier. The ripple is small in terms of B-field, but the high frequency content contributes to a peak dB/dt up to 18 times larger than that predicted by the slew rate (4T/sm) and the distance from the isocenter. Measurements on a 3T MRI scanner, however, revealed a much smaller filtered ripple of 100kHz in dB/dt. These findings suggest that the gradient current to each coil together with information on the geometrical distribution of the gradient field and ripple effects could be used to assess the SGF exposure within an MRI bore.

  • 14.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Exposure assessment of electromagnetic fields near electrosurgical units.2010Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 31, nr 7, s. 513-518Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrosurgical units (ESU) are widely used in medical health services. By applying sinusoidal or pulsed voltage in the frequency range of 0.3-5 MHz to the electrode tip, the desired mixture of coagulation and cutting are achieved. Due to the high voltage and current in the cable, strong electromagnetic fields appear near the ESU. The surgeon and others inside the operating room such as nurses, anesthesiologists, etc., will be highly exposed to these fields. The stray fields surrounding the ESU have previously been measured, but now a deeper analysis has been made of the curve shape of the field and the implication of this when assessing exposure from a commonly used ESU in accordance with the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The result showed that for some of the modes, especially those using high-pulsed voltage with only a few sinusoidal periods, the E-field close to the cable could reach linear spatially averaged values of 20 kV/m compared to the 2.1 kV/m stated in ICNIRP guidelines. Assessing the E- and B-field from ESU is not straightforward since in this frequency range, both induced current density and specific absorption rate are restricted by the ICNIRP guidelines. Nevertheless, work needs to be done to reduce the stray fields from ESU. Bioelectromagnetics (c) 2010 Wiley-Liss, Inc.

  • 15.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Radiofrequency fields: exposure, dose and health2002Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The overall aim of this thesis is to increase our knowledge of relevant exposure parameters when discussing possible health implication from exposure to radiofrequency electromagnetic fields (RF), especially effects that might occur at non-thermal levels.

    In this thesis an effort is made to broaden the exposure assessment and to take the exposure time into account and combine it with the Specific Absorption Rate (SAR) and the field parameters (electric and magnetic field strength) to approach a dose concept.

    In the first part of the thesis self-reported subjective symptoms among mobile phone users were studied. As a basis for this an epidemiological study among mobile phone users was completed with the main hypothesis that users of the digital transmission system GSM experience more symptoms than users of the older analogue NMT transmission system.

    The hypothesis was falsified, but an interesting side finding was that people with longer calling time per day experienced more symptoms than people with shorter calling time per day. The time-aspect (long duration phone call etc.) was also found to be relevant for the occurrence of symptoms in association with mobile phone use as well as duration of symptoms. The new suggested dosimetric quantity Specific Absorption per Day (SAD), in which both calling time per day as well as the measured SAR1g are included showed a stronger association to the prevalence of some of the symptoms, such as dizziness, discomfort and warmth behind the ear compared to both CT and SAR1g alone.

    In the second part whole body exposure conditions were considered. Methods to measure the induced current were examined in an experimental study, where different techniques were compared in different grounding conditions. The results were used in a study of operators of RF plastic sealers (RF operators) where the health status as well as the exposure were studied. The results showed that RF operators are a highly exposed group, which was confirmed by the fact that 16 out of 46 measured work places exceeded the ICNIRP guidelines. Headaches were found to be associated with the mean value of the time integrated E-field during a weld (E-weld) and the warmth sensations in the hands (warm hands) with the time integrated E-field exposure during one day (E-day).

    The general findings in this thesis indicated that time should be included in the exposure assessment when studying non-thermal effects such as subjective symptoms in connection with RF exposure. The thesis proposes two different methods for doing this, namely timeintegrated exposure [V/m x t and A/m x t] and dose [J/kg].

  • 16.
    Wilén, Jonna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    de Vocht, Frank
    Health complaints among nurses working near MRI scanners-A descriptive pilot study2011Ingår i: European Journal of Radiology, ISSN 0720-048X, E-ISSN 1872-7727, Vol. 80, nr 2, s. 510-513Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A questionnaire-based descriptive pilot study was conducted among all nurses routinely working with MRI in the Northern part of Sweden to provide an indication of the self-reported prevalence of health complaints related to working with MRI systems. Fifty-nine nurses (88% response rate), with on average 8 (±6) years experience with MRI scanning procedures, returned the questionnaire. In total, 9 nurses (15%) reported regularly experiencing at least one of the health complaints (1-5% for specific health complaints) attributed to arise or be aggravated by their presence in the MRI scanning room. Stratification of the results indicated that reporting of adverse symptoms was not related to the level of occupational workload/stress. However, reporting of health complaints was related to the strength of the magnet(s) the nurses worked with, with 57% of symptoms reported by those nurses working with the strongest systems (both 1.5 and 3T scanners in this population). Although this descriptive study did not include a control population and was based on self-reporting of health complaints, these data indicate that the prevalence of reported health complaints is not related to perceived work load or occupational stress, but does confirm data from other occupational sectors and indicates that the prevalence of adverse health complaints increases with the strength of the MRI system for nurses as well.

  • 17.
    Wilén, Jonna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Lundström, Ronnie
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Non-Ionising Radiation in Swedish Health Care2018Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Bakgrund

    Inom sjukvården används alltmera teknik som exponerar patienter för icke-joniserande strålning vid diagnostik och terapi. Ofta används sådan teknik som ett alternativ till och ibland i kombination med metoder som exponerar för joniserande strålning.

    Huvudsyftet med studien var att identifiera och beskriva hur icke-joniserande strålning används inom hälso- och sjukvård, samt att undersöka förväntade exponeringsnivåer, identifiera eventuella hälsorisker och identifiera kunskapsluckor inom området. Icke-joniserande strålning refererar här till icke-joniserande elektromagnetisk strålning med frekvenser från 0 Hz upp till 3,0 PHz, inkluderande elektromagnetiska fält, optisk strålning och mekaniska vågor såsom ultraljud.

    SSM har saknat en samlad kunskap kring de metoder och exponeringsnivåer som använder icke-joniserande strålning inom sjukvården. Bland annat EU:s vetenskapliga råd SCENIHR (har numera bytt namn till SCHEER) har pekat på behovet av forskning om potentiella hälsoeffekter inom detta område. Studien var alltså viktig för att få ett underlag för att bedöma behovet av ytterligare säkerhetsåtgärder inom området, identifiera kunskapsluckor och också för att få ett bättre underlag för att besvara frågor angående säkerhet och eventuella risker.

    Resultat

    Inga hälsorisker eller allvarliga säkerhetsbrister har identifierats. Däremot är de exponeringsnivåer som används många gånger på en nivå där det finns en tydlig biologisk påverkan och ibland kan även akuta symtom upplevas, detta är dock ofta helt avsiktligt för att få önskad effekt och av övergående natur.

    Författarna har identifierat ett behov av att förbättra hälsovårdspersonalens kunskap om risker och säkerhet vid användning av icke-joniserande strålning samt pekar på vikten av tydlighet när det gäller vilken organisation/myndighet som ska tillhandahålla sådan information.

    Rapporten indikerar också att ett robust forskningsunderlag för närvarande saknas för att bedöma möjliga långsiktiga hälsorisker med användning av exempelvis MRI, TMS och ultraljud. Den kunskap och forskning som finns tillgänglig tyder dock inte på några betydande hälsorisker med nu aktuella exponeringsnivåer.

    Relevans

    Rapporten stöder Strålsäkerhetsmyndighetens tidigare uppfattning att de tillämpningar med icke-joniserande strålning som används i sjukvården inte utgör några kända hälsorisker. När metoder som bygger på icke-joniserande strålning ersätter metoder som bygger på joniserande strålning ökar patientsäkerheten, under förutsättning att syftet med undersökningen eller behandlingen uppnås.

  • 18.
    Wilén, Jonna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hauksson, Jón
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hansson Mild, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Modification of pulse sequences reduces occupational exposure from MRI switched gradient fields: Preliminary results.2010Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 31, nr 1, s. 85-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The gradient fields in magnetic resonance imaging (MRI) will in some circumstances exceed the ICNIRP guidelines of occupational electromagnetic field exposure when personnel are near the scanner during MRI scanning. In this work we have shown that using commercially available modified sequences for noise reduction purposes, exposure will decrease by a factor of 1.5 with preserved image quality. This is a first step toward optimizing occupational exposure within the scanner room without affecting image quality. Bioelectromagnetics 31:85-87, 2010. (c) 2009 Wiley-Liss, Inc.

  • 19.
    Wilén, Jonna
    et al.
    National Institute for Working Life, Umeå, Sweden.
    Hörnsten, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Klinisk fysiologi. National Institute for Working Life, Umeå, Sweden.
    Sandström, Monica
    National Institute for Working Life, Umeå, Sweden.
    Bjerle, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Klinisk fysiologi.
    Wiklund, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Klinisk fysiologi. Biomedical Engineering & Informatics, University Hospital, Umeå, Sweden.
    Stensson, Olov
    National Institute for Working Life, Umeå, Sweden.
    Lyskov, Eugene
    Centre for Musculoskeletal Research, University of Gävle, Sweden.
    Hansson Mild, Kjell
    National Institute for Working Life, Umeå, Sweden.
    Electromagnetic field exposure and health among RF plastic sealer operators2004Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 25, nr 1, s. 5-15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Operators of RF plastic sealers (RF operators) are an occupational category highly exposed to radiofrequency electromagnetic fields. The aim of the present study was to make an appropriate exposure assessment of RF welding and examine the health status of the operators. In total, 35 RF operators and 37 controls were included. The leakage fields (electric and magnetic field strength) were measured, as well as induced and contact current. Information about welding time and productivity was used to calculate time integrated exposure. A neurophysiological examination and 24 h ECG were also carried out. The participants also had to answer a questionnaire about subjective symptoms. The measurements showed that RF operators were exposed to rather intense electric and magnetic fields. The mean values of the calculated 6 min, spatially averaged E and H field strengths, in line with ICNIRP reference levels, are 107 V/m and 0.24 A/m, respectively. The maximum measured field strengths were 2 kV/m and 1.5 A/m, respectively. The induced current in ankles and wrists varied, depending on the work situation, with a mean value of 101 mA and a maximum measured value of 1 A. In total, 11 out of 46 measured RF plastic sealers exceeded the ICNIRP reference levels. RF operators, especially the ready made clothing workers had a slightly disturbed two-point discrimination ability compared to a control group. A nonsignificant difference between RF operators and controls was found in the prevalence of subjective symptoms, but the time integrated exposure parameters seem to be of importance to the prevalence of some subjective symptoms: fatigue, headaches, and warmth sensations in the hands. Further, RF operators had a significantly lower heart rate (24 h registration) and more episodes of bradycardia compared to controls.

  • 20.
    Wilén, Jonna
    et al.
    National Institute for Working Life.
    Johansson, Amanda
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin. Yrkes- och miljömedicin.
    Kalezic, Nebojsa
    Lyskov, Eugene
    Sandström, Monica
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin. Yrkes- och miljömedicin.
    Psychophysiological tests and provocation of subjects with mobile phone related symptoms.2006Ingår i: Bioelectromagnetics, ISSN 0197-8462, Vol. 27, nr 3, s. 204-214Artikel i tidskrift (Refereegranskat)
  • 21.
    Wilén, Jonna
    et al.
    National Institute for Working Life.
    Sandström, Monica
    National Institute for Working Life.
    Hansson Mild, Kjell
    National Institute for Working Life.
    Subjective symptoms among mobile phone users: a consequence of absorption of radiofrequency fields?2003Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 24, nr 3, s. 152-159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In a previous epidemiological study, where we studied the prevalence of subjective symptoms among mobile phone (MP) users, we found as an interesting side finding that the prevalence of many of the subjective symptoms increased with increasing calling time and number of calls per day. In this extrapolative study, we have selected 2402 people from the epidemiological study who used any of the four most common GSM MP. We used the information about the prevalence of symptoms, calling time per day, and number of calls per day and combined it with measurements of the Specific Absorption Rate (SAR). We defined three volumes in the head and measured the maximum SAR averaged over a cube of 1 g tissue (SAR(1g)) in each volume. Two new exposure parameters Specific Absorption per Day (SAD) and Specific Absorption per Call (SAC) have been devised and are obtained as combinations of SAR, calling time per day, and number of calls per day, respectively. The results indicates that SAR values >0.5 W/kg may be an important factor for the prevalence of some of the symptoms, especially in combination with long calling times per day.

  • 22.
    Wilén, Jonna
    et al.
    National Institute for Working Life, Umeå.
    Wiklund, Urban
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper.
    Hörnsten, Rolf
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Klinisk fysiologi.
    Sandström, Monica
    Umeå universitet, Medicinsk fakultet, Folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Changes in heart rate variability among RF plastic sealer operators.2007Ingår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 28, nr 1, s. 76-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In a previous study, we showed that operators of radiofrequency (RF) plastic sealers, RF operators (n = 35) had a lower heart rate during nighttime compared to a control group (n = 37). We have analyzed the heart rate variability (HRV) on the same group of people to better understand the possible underlying rhythm disturbances. We found a significantly increased total HRV and very low frequency (VLF) power during nighttime among the RF operators compared to a control group. Together with our previous finding of a significantly lower heart rate during nighttime among the RF operators compared to the controls, this finding indicates a relative increase in parasympathetic cardiac modulation in RF operators. This could in turn be due to an adaptation of the thermoregulatory system and the cardiac autonomic modulation to a long-term low-level thermal exposure in the RF operators.

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