Risks related to RF fields

Abstract

One of the main safety concerns in MRI is the interaction between the electric field produced by the RF coil and conductive tissue and any implants within the patient. This results in power deposition and potential heating. International safety guidelines are formulated in terms of specific absorption rate (SAR) rather than rises in temperature, although there are strong indications that future regulations will concentrate on direct thermal effects. The effects of implants can be studied via electromagnetic simulations and phantom experiments. As MRI static magnetic fields increase local and global SAR values also become higher, and asymmetry in their spatial distribution also increases. This talk will concentrate on methods to simulate and measure RF heating, both using MRI and MRI-compatible optical techniques, and suggest some methods for potentially reducing heating using targeted RF fields.