A health and safety model for occupational exposure to radiofrequency fields and static magnetic fields from 1.5 and 3 T MRI scanners

Rathebe, Phoka C.; Weyers, C.; Raphela, F.

doi:10.1007/s12553-019-00379-4

Cited by 7 publications

(7 citation statements)

References 39 publications

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“…The International Society for Magnetic Resonance in Medicine (ISMRM) has recently endorsed the best practice or guidance on RF safety-related MRI experiments and/or numerical assessments [ 7 , 8 ]. Several studies have assessed RF safety during MRI scans for workers [ 9 , 10 , 11 , 12 ] and patients, including adults with implanted medical devices [ 13 , 14 , 15 , 16 , 17 ] and the general public [ 18 , 19 , 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Proposed Safety Guidelines for Patient Assistants in an Open MRI Environment

Hong²,

Choi³

2022

IJERPH

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The wide-open side of an open magnetic resonance imaging (MRI) system allows a patient to easily contact the patient assistant during MRI scans. A wide-open-shaped magnet is highly effective when interventional procedures are necessary. Patient assistants can provide comfort by holding a part of the patient’s body. Because current regulations or guidelines are concerned with only patient radio frequency (RF) safety, investigations on the safety of patient assistants exposed to high-magnetic field MRI (up to 1.2 T) are required. In this study, five different poses of patient assistants were numerically simulated at a 1.2 T open MRI system to determine the impact of poses on the RF exposure level. The 10-g averaged specific absorption rate (SAR) levels were analyzed for the poses of each patient assistant wearing gloves. Compared with the patient, up to 29.8% of the patient SAR was observed in the patient assistant. When the patient assistant wore latex gloves, a 63.7% reduction in the 10-g averaged SAR level was observed, which could be a remedy to minimize possible RF hazards. To prevent possible RF hazards during MRI scans, certain clauses regarding the patient assistant’s poses or wearing gloves must be added to the existing MRI screening forms.

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Section: Introductionmentioning

confidence: 99%

Proposed Safety Guidelines for Patient Assistants in an Open MRI Environment

Hong²,

Choi³

2022

IJERPH

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“…To prevent the extra electromagnetic wave, due to the electrostatic equipotentiality of metals, electromagnetic interference (EMI) shielding material can effectively shield external electric fields from electromagnetic interference. The setup of EMI shielding protective clothing should comply with the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (18th individual directive within the meaning of Article 16 (1) of Directive 89/391/EEC), which require the employee to use suitable protective equipment to work in high electromagnetic radiation environments [5]. The research on metal-coated textiles has proven the effectiveness of EMI shielding in many applications.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin Multilayer Textile Structure with Enhanced EMI Shielding and Air-Permeable Properties

Wang

Periyasamy

et al. 2021

Polymers

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A textile material’s electromagnetic interference (EMI) shielding effectiveness mainly depends on the material’s electrical conductivity and porosity. Enhancing the conductivity of the material surface can effectively improve the electromagnetic shielding effectiveness. However, the use of highly conductive materials increases production cost, and limits the enhancement of electromagnetic shielding effectiveness. This work aims to improve the EMI shielding effectiveness (EMSE) by using an ultrathin multilayer structure and the air-permeable textile MEFTEX. MEFTEX is a copper-coated non-woven ultrathin fabric. The single-layer MEFTEX SE test results show that the higher its mass per unit area (MEFTEX 30), the better its SE property between 56.14 dB and 62.53 dB in the frequency band 30 MHz–1.5 GHz. Through comparative testing of three groups samples, a higher electromagnetic shielding effect is obtained via multilayer structures due to the increase in thickness and decrease of volume electrical resistivity. Compared to a single layer, the EMI shielding effectiveness of five layers of MEFTEX increases by 44.27–83.8%. Due to its ultrathin and porous structure, and considering the balance from porosity and SE, MEFTEX 10 with three to four layers can still maintain air permeability from 2942 L/m2/s–3658 L/m2/s.

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“…Several studies have assessed the RF safety during MRI scans for workers [7][8][9] and patients such as adults with implanted medical devices [10][11][12], the general public [13][14][15][16], and pregnant women and their fetuses [17][18][19]. However, there have been few studies on the EMF exposure of patient assistants during MRI scans.…”

Section: Introductionmentioning

confidence: 99%

RF Exposure Assessment for Various Poses of Patient Assistant in Open MRI Environment

Hong

Choi

2021

Applied Sciences

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In this study, the radio-frequency (RF) energy exposure of patient assistants was assessed for an open magnetic resonance imaging (MRI) system based on numerical computations of the head and body RF coil. Various poses of the patient assistants were defined to see how poorly they affected the RF energy exposure. For the assessments, the peak spatial-averaged specific absorption rate (SAR) levels were carefully compared with each patient assistant pose based on the finite-difference time domain calculations of RF coil models when the patient was placed in such coils in a 0.3 Tesla open MRI system. Overall, the SAR levels of the patient assistant were much lower than those of the patient. However, significantly increased SAR levels were observed under specific conditions, including a larger loop size of the patient assistants’ arms and a closer distance to the RF coils. A comparably high level of SAR to the patient’s body was also found. More careful investigations are needed to prevent the increase of SAR in patient assistants for open MRI systems at higher field strengths.

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A health and safety model for occupational exposure to radiofrequency fields and static magnetic fields from 1.5 and 3 T MRI scanners

Cited by 7 publications

References 39 publications

Proposed Safety Guidelines for Patient Assistants in an Open MRI Environment

Proposed Safety Guidelines for Patient Assistants in an Open MRI Environment

Ultrathin Multilayer Textile Structure with Enhanced EMI Shielding and Air-Permeable Properties

RF Exposure Assessment for Various Poses of Patient Assistant in Open MRI Environment

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