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

Impacts of 1.5 T MRI Static Magnetic Field on Biochemical and Enzyme Activity Parameters on Radiology Department Workers

Magnetic Resonance Imaging (MRI) is an important diagnostic technique that uses powerful magnetic fields to generate detailed images of the human body. The aim of this study is to investigate to how static magnetic fields (SMF) affect the levels of trace elements and biochemical parameters in MRI staff' blood serum. This study examines the impacts of these exposures of 18 participants (9 males and 9 females) aged between 25 and 60.on the levels of trace elements in the blood serum and the biochemical parameters of the MRI staff at Azadi Teaching Hospital in Duhok and Zakho General Hospital-Bidari in Zakho City. Eighteen participants, consisting of nine males and nine females aged between 25 and 60, were selected from these hospitals. The researchers obtained blood samples and conducted analysis to determine the presence of trace elements (sodium, potassium, calcium, chloride) as well as numerous biochemical markers. The results showed that potassium and calcium levels increased with age, and older females had considerable deviations. Chloride levels exhibited a significant increase with age in both males and females. Glucose, creatinine, uric acid, and urea levels showed an increase with age, suggesting the possible damage to kidney function caused by continuous exposure to MRI. Increased levels of liver enzymes (GPT, GOT, ALP) and thyroid-stimulating hormone (TSH) were noticed, particularly in older females, indicating potential liver and thyroid dysfunction. These results highlight the importance of applying strict safety protocols and conducting regular health assessments for MRI personnel to minimize the possible hazards.

Dynamic Flexion-Extension Magnetic Resonance Imaging of the Cervical Spine: An Evolutionary Tool for Diagnosis and Management of Cervical Spondylotic Myelopathy

Dynamic problems need dynamic solutions. High motility of the cervical spine causes a common age-related degenerative condition called cervical spondylotic myelopathy (CSM), manifested by neurological impairments. An accurate and reliable diagnosis of CSM is crucial for determining appropriate management strategies. Traditional static magnetic resonance imaging (MRI) has been the gold standard for imaging CSM; however, it may not fully capture dynamic changes during neck movement. Dynamic flexion-extension (DFE) MRI is an innovative imaging technique that allows for real-time visualization of cervical spine motion. This review article aims to scrutinize the role of DFE MRI in assessing CSM, its added value to clinical implementations, and its limitations. Finally, by addressing the knowledge gaps, this survey sheds light on the road ahead to incorporate DFE MRI into a standard version of the practice.

SORDOR pulses: expansion of the Böhlen-Bodenhausen scheme for low-power broadband magnetic resonance

A novel type of efficient broadband pulse, called second-order phase dispersion by optimised rotation (SORDOR), has recently been introduced. In contrast to adiabatic excitation, SORDOR-90 pulses provide effective transverse 90∘ rotations throughout their bandwidth, with a quadratic offset dependence of the phase in the x , y plane. Together with phase-matched SORDOR-180 pulses, this enables the Böhlen-Bodenhausen broadband refocusing approach for linearly frequency-swept pulses to be extended to any type of 90∘ /180∘ pulse-delay sequence. Example pulse shapes are characterised in theory and experiment, and an example application is given with a 19 F -PROJECT experiment for measuring relaxation times with reduced distortions due to J -coupling evolution.

Subjective symptoms of SMFs and RF energy, and risk perception among staff working with MR scanners within two public hospitals in South Africa

This study assessed subjective symptoms associated with exposure to static magnetic fields (SMFs) and radiofrequency (RF) energy, and perceived safety risk of scanners among magnetic resonance (MR) staff working in the 1.5 and 3 T MRI units. A questionnaire survey was completed by 77 clinical imaging staff working in two hospitals (A and B) in the Mangaung metropolitan region. 50 participants working with the MR scanners were regarded as exposed group and 27 participants from CT scan and X-ray departments were classified as control group. The study comprised 57% females and 43% male participants with an average MRI experience of 5.4 years. Using logistic regression, tinnitus was significantly different between various job titles (p< .034) and it was reported more often (OR 8:00; CI 1.51, 15.17) by those who worked on a 3 T scanner. Increased years of MRI experience was a significant predictor of headache (p< .05), and reporting of nausea was significantly different between various job titles (p < .01). There was an increased risks of reporting vertigo often among female participants (OR: 4.43; CI 0.91, 21.47), those with 5-15 years of MRI experience (OR: 2.09; CI 0.47, 9.34), and those with a light to moderate workload (OR: 2.70; CI 0.49, 14.86). Using linear regression, presence in zone IV during image acquisitioning was the only significant predictor for the sensation of glowing (p < .000). Movement of head/ upper body in the scanner bore was a significant predictor of nausea (p< .026), vertigo (p< .014), instability when standing (p< .014), and a metallic taste (p< .031). There was no correlation between reporting of symptoms and perceived risk of scanners. However, shift duration (r_s = 0.576), movement of head/upper body in the scanner bore (r_s = 0.424), and strength of the scanners (r_s = 0.299) were significantly correlated with perceived risk of scanners. MRI safety training and a comprehensive occupational health and safety program are necessary.

Occupational exposure to electromagnetic fields in magnetic resonance environment: an update on regulation, exposure assessment techniques, health risk evaluation, and surveillance

Magnetic resonance imaging (MRI) is one of the most-used diagnostic imaging methods worldwide. There are ∼50,000 MRI scanners worldwide each of which involves a minimum of five workers from different disciplines who spend their working days around MRI scanners. This review analyzes the state of the art of literature about the several aspects of the occupational exposure to electromagnetic fields (EMF) in MRI: regulations, literature studies on biological effects, and health surveillance are addressed here in detail, along with a summary of the main approaches for exposure assessment. The original research papers published from 2013 to 2021 in international peer-reviewed journals, in the English language, are analyzed, together with documents published by legislative bodies. The key points for each topic are identified and described together with useful tips for precise safeguarding of MRI operators, in terms of exposure assessment, studies on biological effects, and health surveillance.

Static Magnetic Field (0.2-0.4 T) Stimulates the Self-Renewal Ability of Osteosarcoma Stem Cells Through Autophagic Degradation of Ferritin

Static magnetic field (SMF) can alter cell fate decisions in many ways. However, the effects of SMF on cancer stem cells (CSCs) are little-known. In this particular study, we evaluate the biological effect of moderate-intensity SMF on osteosarcoma stem cells (OSCs) and try to clarify the underlying mechanisms of action. First, we demonstrated that prolonged exposure to SMF induced the proliferation and tumorsphere formation in K7M2 and MG63 OSCs. Moreover, SMF promoted the release of ferrous iron (Fe²⁺ ) and provoked reactive oxygen species (ROS) in OSCs. Interestingly, SMF evidently triggered the autophagic degradation of ferritin, which is characterized by the activation of microtubule-associated protein 1 light chain 3 (LC3) and nuclear receptor co-activator 4 (NCOA4), and downregulation of ferritin heavy chain 1 (FTH1) in OSCs. Particularly, the colony-forming ability of K7M2 OSCs promoted by SMF was obviously abolished by using a small interfering RNA (siRNA) against NCOA4. Finally, treatment of the tumor-bearing mice with SMF did not affect the tumor volume or tumor mass, nor pulmonary metastasis of K7M2 OSCs, but the SMF-treated K7M2 OSCs caused a preference of pulmonary metastasis in a mouse model, which suggested that SMF might induce the metastatic characteristic of OSCs. Consequently, this paper demonstrates for the first time that the cumulative SMF exposure promoted the self-renewal ability of OSCs via autophagic degradation of ferritin, implying that ferritinophagy may be a potential molecular target for cancer. © 2021 Bioelectromagnetics Society.

Radiation Safety Concerns Related to PET/Computed Tomography Imaging for Assessing Pediatric Diseases and Disorders

The Image Gently Nuclear Medicine Working Group published a 10-year update in 2019. One of the future goals of this working group is to continue the efforts started in 2014 to harmonize the North American guidelines with the European Association of Nuclear Medicine pediatric dosing guidelines, continuing to publicize the use of the North American guidelines. The update also acknowledged the need for standardization of CT parameters in hybrid imaging and also will seek to tackle this issue as one of its future goals.

Exposure levels of radiofrequency magnetic fields and static magnetic fields in 1.5 and 3.0 T MRI units

Magnetic resonance imaging (MRI) staff is exposed to a complex mixture of electromagnetic fields from MRI units. Exposure to these fields results in the development of transient exposure-related symptoms. This study aimed to investigate the exposure levels of radiofrequency (RF) magnetic fields and static magnetic fields (SMFs) from 1.5 and 3.0 T MRI scanners in two public hospitals in the Mangaung Metropolitan region, South Africa. The exposure levels of SMFs and RF magnetic fields were measured using the THM1176 3-Axis hall magnetometer and TM-196 3 Axis RF field strength meter, respectively. Measurements were collected at a distance of 1 m (m) and 2 m from the gantry for SMFs when the brain, cervical spine and extremities were scanned. Measurements for RF magnetic fields were collected at a distance of 1 m with an average scan duration of six minutes. Friedman’s test was used to compared exposure mean values from two 1.5 T scanners, and Wilcoxon test with Bonferroni adjustment was used to identify where the difference between exist. The Shapiro–Wilk test was also used to test for normality between exposure levels in 1.5 and 3.0 T scanners. The measured peak values for SMFs from the 3.0 T scanner at hospital A were 1300 milliTesla (mT) and 726 mT from 1.5 T scanner in hospital B. The difference in terms of SMFs exposure levels was observed between two 1.5 T scanners at a distance of 2 m. The difference between 1.5 T scanners at 1 m was also observed during repeated measurements when brain, cervical spine and extremities scans were performed. Scanners’ configurations, magnet type, clinical setting and location were identified as factors that could influence different propagation of SMFs between scanners of the same nominal B0. The RF pulse design, sequence setting flip-angle and scans performed influenced the measured RF magnetic fields. Three scanners were complaint with occupational exposure guidelines stipulated by the ICNIRP; however, peak levels that exist at 1 m could be managed through adoption of occupational health and safety programs.

Radiation protection in non-ionizing and ionizing body composition assessment procedures

Body composition assessment (BCA) represents a valid instrument to evaluate nutritional status through the quantification of lean and fat tissue, in healthy subjects and sick patients. According to the clinical indication, body composition (BC) can be assessed by different modalities. To better analyze radiation risks for patients involved, BCA procedures can be divided into two main groups: the first based on the use of ionizing radiation (IR), involving dual energy X-ray absorptiometry (DXA) and computed tomography (CT), and others based on non-ionizing radiation (NIR) [magnetic resonance imaging (MRI)]. Ultrasound (US) techniques using mechanical waves represent a separate group. The purpose of our study was to analyze publications about IR and NIR effects in order to make physicians aware about the risks for patients undergoing medical procedures to assess BCA providing to guide them towards choosing the most suitable method. To this end we reported the biological effects of IR and NIR and their associated risks, with a special regard to the excess risk of death from radio-induced cancer. Furthermore, we reported and compared doses obtained from different IR techniques, giving practical indications on the optimization process. We also summarized current recommendations and limits for techniques employing NIR and US. The authors conclude that IR imaging procedures carry relatively small individual risks that are usually justified by the medical need of patients, especially when the optimization principle is applied. As regards NIR imaging procedures, a few studies have been conducted on interactions between electromagnetic fields involved in MR exam and biological tissue. To date, no clear link exists between MRI or associated magnetic and pulsed radio frequency (RF) fields and subsequent health risks, whereas acute effects such as tissue burns and phosphenes are well-known; as regards the DNA damage and the capability of NIR to break chemical bonds, they are not yet robustly demonstrated. MRI is thus considered to be very safe for BCA as well US procedures.

Valid Exposure Protocols Needed in Magnetic Resonance Imaging Genotoxic Research

Several in vitro and in vivo studies have investigated if a magnetic resonance imaging (MRI) examination can cause DNA damage in human blood cells. However, the electromagnetic field (EMF) exposure that the cells received in the MR scanner was not sufficiently described. The first studies looking into this could be regarded as hypothesis-generating studies. However, for further exploration into the role of MRI exposure on DNA integrity, the exposure itself cannot be ignored. The lack of sufficient method descriptions makes the early experiments difficult, if not impossible, to repeat. The golden rule in all experimental work is that a study should be repeatable by someone with the right knowledge and equipment, and this is simply not the case with many of the recent studies on MRI and genotoxicity. Here we discuss what is lacking in previous studies, and how we think the next generation of in vitro and in vivo studies on MRI and genotoxicity should be performed. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

Non-Ionizing Radiation in Swedish Health Care-Exposure and Safety Aspects

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.

EMF exposure variation among MRI sequences from pediatric examination protocols

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. Bioelectromagnetics. 40:3-15, 2019. © 2018 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.