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Wilén, Jonna
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Publikasjoner (10 av 22) Visa alla publikasjoner
Frankel, J., Hansson Mild, K., Olsrud, J. & Wilén, J. (2019). EMF exposure variation among MRI sequences from pediatric examination protocols. Bioelectromagnetics, 40(1), 3-15
Åpne denne publikasjonen i ny fane eller vindu >>EMF exposure variation among MRI sequences from pediatric examination protocols
2019 (engelsk)Inngår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 40, nr 1, s. 3-15Artikkel i tidsskrift (Fagfellevurdert) Published
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. 

sted, utgiver, år, opplag, sider
Wiley-Blackwell, 2019
Emneord
children, electromagnetic field, epidemiology, exposure assessment, radiofrequency
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-155086 (URN)10.1002/bem.22159 (DOI)000453860500001 ()30500987 (PubMedID)
Forskningsfinansiär
Swedish Research Council, 521-2013-2702
Tilgjengelig fra: 2019-01-10 Laget: 2019-01-10 Sist oppdatert: 2019-01-10bibliografisk kontrollert
Hansson Mild, K., Lundström, R. & Wilén, J. (2019). Non-Ionizing Radiation in Swedish Health CareExposure and Safety Aspects. International Journal of Environmental Research and Public Health, 16(7), Article ID 1186.
Åpne denne publikasjonen i ny fane eller vindu >>Non-Ionizing Radiation in Swedish Health CareExposure and Safety Aspects
2019 (engelsk)Inngår i: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, nr 7, artikkel-id 1186Artikkel i tidsskrift (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
MDPI, 2019
Emneord
NIR, health care, exposure, safety, EMF, MRI, TMS, UV, Laser
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-159074 (URN)10.3390/ijerph16071186 (DOI)000465595800099 ()30987016 (PubMedID)
Tilgjengelig fra: 2019-05-20 Laget: 2019-05-20 Sist oppdatert: 2019-05-20bibliografisk kontrollert
Hansson, B., Höglund, P., Markenroth Bloch, K., Nilsson, M., Olsrud, J., Wilén, J. & Björkman-Burtscher, I. M. (2019). Short-term effects experienced during examinations in an actively shielded 7 T MR. Bioelectromagnetics, 40(4), 234-249
Åpne denne publikasjonen i ny fane eller vindu >>Short-term effects experienced during examinations in an actively shielded 7 T MR
Vise andre…
2019 (engelsk)Inngår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 40, nr 4, s. 234-249Artikkel i tidsskrift (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
John Wiley & Sons, 2019
Emneord
dizziness, peripheral nerve stimulation, motion, patient compliance, bias
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-159063 (URN)10.1002/bem.22189 (DOI)000466559000002 ()30920671 (PubMedID)
Tilgjengelig fra: 2019-05-21 Laget: 2019-05-21 Sist oppdatert: 2019-05-21bibliografisk kontrollert
Frankel, J., Wilén, J. & Hansson Mild, K. (2018). 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 Patients. Frontiers In Public Health, 6, Article ID 66.
Åpne denne publikasjonen i ny fane eller vindu >>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 Patients
2018 (engelsk)Inngår i: Frontiers In Public Health, ISSN 2296-2565, Vol. 6, artikkel-id 66Artikkel i tidsskrift (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
Frontiers Media S.A., 2018
Emneord
electromagnetic field, occupational exposure, switched gradient field, diagnostic imaging, asurement
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-147347 (URN)10.3389/fpubh.2018.00066 (DOI)000429555100001 ()29594090 (PubMedID)
Tilgjengelig fra: 2018-05-11 Laget: 2018-05-11 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Wilén, J., Hansson Mild, K. & Lundström, R. (2018). Non-Ionising Radiation in Swedish Health Care. Stockholm: Strålsäkerhetsmyndigheten
Åpne denne publikasjonen i ny fane eller vindu >>Non-Ionising Radiation in Swedish Health Care
2018 (engelsk)Rapport (Annet vitenskapelig)
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.

sted, utgiver, år, opplag, sider
Stockholm: Strålsäkerhetsmyndigheten, 2018. s. 94
Serie
SSM, ISSN 2000-0456 ; 2017:37
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-158401 (URN)
Prosjekter
SSM 2016-498 / 7030054-00
Tilgjengelig fra: 2019-04-26 Laget: 2019-04-26 Sist oppdatert: 2019-04-26bibliografisk kontrollert
Mild, K. H., Friberg, S., Frankel, J. & Wilen, J. (2017). Exposure to the magnetic field from an induction loop pad for a hearing aid system. International Journal of Occupational Safety and Ergonomics, 23(1), 143-145
Åpne denne publikasjonen i ny fane eller vindu >>Exposure to the magnetic field from an induction loop pad for a hearing aid system
2017 (engelsk)Inngår i: International Journal of Occupational Safety and Ergonomics, ISSN 1080-3548, E-ISSN 2376-9130, Vol. 23, nr 1, s. 143-145Artikkel i tidsskrift (Fagfellevurdert) Published
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.

Emneord
hearing aid, cancer, reproduction, tamoxifen
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-132622 (URN)10.1080/10803548.2016.1226597 (DOI)000393712900016 ()
Tilgjengelig fra: 2017-08-14 Laget: 2017-08-14 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Sundström, H., Hansson Mild, K. & Wilen, J. (2015). Measurements of the Ripple Effect and Geometric Distribution of Switched Gradient Fields Inside a Magnetic Resonance Scanner. Bioelectromagnetics, 36(2), 162-168
Åpne denne publikasjonen i ny fane eller vindu >>Measurements of the Ripple Effect and Geometric Distribution of Switched Gradient Fields Inside a Magnetic Resonance Scanner
2015 (engelsk)Inngår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 36, nr 2, s. 162-168Artikkel i tidsskrift (Fagfellevurdert) Published
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.

Emneord
MRI patient exposure, gradient ripple, 1, 5T MR, peak dB, dt
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-100959 (URN)10.1002/bem.21884 (DOI)000349650400007 ()25399749 (PubMedID)
Tilgjengelig fra: 2015-03-18 Laget: 2015-03-16 Sist oppdatert: 2018-06-07bibliografisk kontrollert
Hansson Mild, K., Hand, J., Hietanen, M., Gowland, P., Karpowicz, J., Keevil, S., . . . Wilén, J. (2013). Exposure classification of MRI workers in epidemiological studies [Letter to the editor]. Bioelectromagnetics, 34(1), 81-84
Åpne denne publikasjonen i ny fane eller vindu >>Exposure classification of MRI workers in epidemiological studies
Vise andre…
2013 (engelsk)Inngår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 34, nr 1, s. 81-84Artikkel i tidsskrift, Letter (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
Malden, MA: Wiley-Blackwell, 2013
Emneord
occupational exposure, magnetic field, radiographers, nurses, anesthestetists, technicians, engineers
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-54623 (URN)10.1002/bem.21728 (DOI)000312342800010 ()22532229 (PubMedID)
Tilgjengelig fra: 2012-05-02 Laget: 2012-05-02 Sist oppdatert: 2018-06-08bibliografisk kontrollert
de Vocht, F., Wilén, J., Hansson Mild, K., van Nierop, L. E., Slottje, P. & Kromhout, H. (2012). Health effects and safety of magnetic resonance imaging. Journal of medical systems, 36(3), 1779-1780
Åpne denne publikasjonen i ny fane eller vindu >>Health effects and safety of magnetic resonance imaging
Vise andre…
2012 (engelsk)Inngår i: Journal of medical systems, ISSN 0148-5598, E-ISSN 1573-689X, Vol. 36, nr 3, s. 1779-1780Artikkel i tidsskrift (Fagfellevurdert) Published
Emneord
Health effects, Magnetic Resonance Imaging, MRI, Safety
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-40869 (URN)10.1007/s10916-010-9637-2 (DOI)21267774 (PubMedID)
Tilgjengelig fra: 2011-03-11 Laget: 2011-03-11 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Wilén, J. & de Vocht, F. (2011). Health complaints among nurses working near MRI scanners-A descriptive pilot study. European Journal of Radiology, 80(2), 510-513
Åpne denne publikasjonen i ny fane eller vindu >>Health complaints among nurses working near MRI scanners-A descriptive pilot study
2011 (engelsk)Inngår i: European Journal of Radiology, ISSN 0720-048X, E-ISSN 1872-7727, Vol. 80, nr 2, s. 510-513Artikkel i tidsskrift (Fagfellevurdert) Published
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.

Emneord
Magnetic resonance imaging, subjective symptoms, static magnetic field, transient effects
HSV kategori
Forskningsprogram
radiofysik
Identifikatorer
urn:nbn:se:umu:diva-40868 (URN)10.1016/j.ejrad.2010.09.021 (DOI)20950976 (PubMedID)
Tilgjengelig fra: 2011-03-11 Laget: 2011-03-11 Sist oppdatert: 2018-06-08bibliografisk kontrollert
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