Biological effects and health implications in magnetic resonance imaging

In this work, the safety aspects of the Magnetic Resonance Imaging and Spec troscopy (MRI/MRS) systems are reviewed. Focus is placed on the interaction between the electric and magnetic fields generated by such instruments and the human body. An understanding of these interactions has become ever mor e important with the push to higher field strengths. Knowledge of MRI safet y can not only guide RF coil and pulse sequence design but can also affect sequence selections, thereby ensuring safe and efficient system operation. Due to the signal to noise advantages of high held MRI systems, increases i n the static magnetic field are inevitable. However, in addition to the sta tic magnetic field, power intense sequences, fast gradient switching, and l ocalized imaging/spectroscopy all have the potential of subjecting the huma n body to intense magnetic and electric held fluctuations. This further acc entuates the need for a detailed understanding of the effects of exposure t o these Fields. In this work, some of the issues addressed are new, while o thers are well established. In either case, it is hoped that this compilati on will enable all of us to pay greater attention to these matters and incr ease the current state of understanding through novel experimental studies. The discussion broadens the range of radio frequency effects to the microw ave limit. This was accomplished in view of the latest efforts for realizat ion of ultra high held (UHF) human MRI. In this regard, recently constructe d ultra high field whole body systems will provide a new testing ground for safety issues. The proliferation of high field (1.0-3.0 tesla), very high field (3.0-7.0 tesla), and ultra high field (greater than or equal to 7 tes la) whole body MRI's calls for a review of the safety literature that can g uide future studies of critical health related issues. An effort has been m ade to present an up to date analysis of the biological effects within MR, covering a wide range of properties from cellular and physiological to clin ical. (C) 2000 John Wiley & Sons, Inc.