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Sodium magnetic resonance is a very promising tool for achieving biochemical information on tissue viability, cell integrity and function in quantitative and noninvasive manner. Although it has already been applied in vivo in most human tissues, the low detectable sodium signal gives rise to technological limitations in terms of data quality when using clinical scanners. The design of dedicated coils capable of providing large field of view with high signal-to-noise ratio data is a requirement for quantifying tissutal sodium. This work describes design, simulation, construction and test of a dual-tuned H-1/Na-23 birdcage coil for magnetic resonance (MR) studies in human calf performed with a 3-T MR scanner. Coil simulation was performed using an electromagnetic solver based on finite-difference time-domain (FDTD) method, while the design included matching, tuning and trap circuits' realization for H-1/Na-23 decoupling. Successively, a prototype of the coil was built and tested at workbench, for quality factors, Q ratio measurements and H-1/Na-23 channels' decoupling evaluation. Finally, the coil was employed in a 3-Tesla scanner for acquiring MR data. The results are presented as signal profiles for both coil channels extracted from the phantom chemical shift image and with in vivo imaging performed on human calfs. The designed dual-tuned coil provided good decoupling between H and Na channels, by permitting to maximize the homogeneity of the magnetic field at both the frequencies of interest. Moreover, the simulations accuracy was demonstrated by good agreement between the theoretical and experimental coil signal profiles

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 analyses the state-of-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 analysed, 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.

Magnetic resonance imaging (MRI) is one of the most common sources of electromagnetic (EM) fields as a diagnostic technique widely used in medicine. MRI staff during the working day is constantly exposed to static and spatially heterogeneous magnetic field. Also, moving around the MRI room to perform their functions, workers are exposed to slowly time-varying magnetic fields that induce electrical currents and fields in the body. The development of new exposure assessment methodologies to collect exposure data at a personal level using simple everyday equipment is hence necessary, also in view of future epidemiological studies. This paper describes the design and testing of a novel device for assessing personal exposure to static and time-varying magnetic fields during daily clinical practice. The dosemeter will be also used to ensure effective training of technicians who will be instructed to avoid, where possible, risk behaviour in terms of high exposure.