Hidden Dangers in MRI: Investigating Heating of Metallic Objects from Switching Gradient Fields

With the number of medical implants increasing every year it is inevitable that some patients with implants will at some time undergo an MRI procedure. Investigating the safety of implants during an MRI scan is vital as with current medical record keeping it can be difficult to track implants, which may put patients in possible danger. It is known in MRI oscillating magnetic fields produced by an MRI scanner have the potential to induce eddy currents in metallic implants in turn these eddy currents can heat surrounding tissue and may potentially cause damage to healthy tissue. However, much of the research evaluating the safety risks that are associated with imaging around metallic implants has focused mainly on the magnetic component of RF radiation present in the MRI scanner, and not much attention has been paid to switching gradient fields in MRI which oscillate at much lower frequencies. We investigate local heating of conductive materials within an MRI scanner producing quantitative data on the position dependence of induced EMF and heating, as well as the interaction between different gradients within the scanner. This work will assist in evaluating any dangers that may be present to patients with a metallic implants.