The MR Environment: Knowing the Risks
May 6, 2015 | Evaluations & Guidance
The opportunity for injury in the MR room remains an issue for all MR users. This is so because of the growing use of medical devices during MR scans, the greater emphasis on maximizing workflow, and the growth in popularity of more powerful MR systems. The clinical literature and problem reporting databases include numerous reports of injuries—and a few deaths—in MR centers. Costly damage can also result.
Many of these incidents occurred because ferromagnetic materials (that is, materials that can become strongly magnetized) were mistakenly brought into the MR environment. The most spectacular outcome of such an error is the projectile effect, in which an object becomes airborne and literally flies through the air, crashing into the magnet or patient. Other incidents can be attributed to the use of devices within the MR environment in a manner not in accordance with their restrictions or limitations. For example, electrically conductive objects, such as sensor leads, are subject to inductive heating when inside the bore of the magnet. In some cases, the heating will cause patient burns.
Although these issues are widely recognized, individual staff members may not always be aware of them. Keeping staff conscious of MR risks is a vital and ongoing priority.
The MR environment is commonly defined as the volume where the magnetic field strength of the MR system is greater than 5 gauss (G), or 0.0005 tesla (T). (1 T = 10,000 G.) This corresponds to MR safety zones 3 and 4 as defined by...