replaced with the optional ‘MR projectile zone’ which can be linked to the 3mT magnetic field contour. This is the relevant static field action level given in the Physical Agents Directive. These areas are shown in figure 1, as are the American College of Radiology recommended zones for comparison.
MR authorised personnel Another common area for concern was the issue of access to and supervision in the MR controlled access area and the relevant training requirements. This was considered to be a particular issue for staff that need to enter the MR controlled access area but do not need to enter the MR environment. It is important that staff working within an MRI unit are suitably trained and aware of their responsibilities for the safety of themselves and others. The guidance has introduced three categories of MR Authorised Personnel:
• MR authorised person (non-MR environment) • MR authorised person (MR environment) • MR authorised person (Supervisor)
This may help to better reflect working practice and clarify responsibilities. Access and supervision rights are summarised in figure 2.
Figure 2: T
Training The training requirements for staff entering the MR controlled access area has been updated, with the addition of a requirement that operators are fully aware of the relevant content of the MRI instructions for use. This is important in terms of the Physical Agents Directive as its MRI exemption requires that the instructions for use are followed. For staff that enter only the MR controlled access area and not the MR environment, a requirement to remain aware of the location of the MR environment and its hazards has been added.
MR conditional implants
The guidance was also updated to be consistent about when patients with MR conditional implants can and cannot enter the MR controlled access area. Entry is allowed if the device is an MR conditional device and the operator has confirmed that all of the implant manufacturer’s stated conditions for safe operation are met.
Ferromagnetic material detectors Ferromagnetic detection systems are intended as ancillary screening devices and are not intended to be used as a replacement for traditional safety programs, training or primary screening methods, but as a complementary tool. We recommend that the layout configuration of the MRI suite should include provision for the siting of ferromagnetic detection systems.
Physical Agents (electromagnetic fields) Directive Since 2002 there has been concern in some quarters around the potential threat the Physical Agents Directive is to MRI. It was introduced under the Workplace Health and Safety Directive to protect workers from various
-44- able of access and supervision rights. MR environment
MR authorised person (Non-MR environment)
MR authorised person (MR environment)
MR authorised person (Supervisor)
May not enter
without supervision May enter
May enter and supervise
Area
MR controlled access area outside the MR environment
May enter and supervise May enter and supervise May enter and supervise
Increasingly, we are seeing patients reporting MRI issues to us directly
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