Comment from Cynthia Madsen

I support Citizen Petition FDA-2026-P-6403 and its request that MRI manufacturers be required to provide end users with information depicting radiofrequency intensity and spatial distribution throughout the patient-accessible area of each MRI system. As a diagnostic imaging leader involved in MRI operations and patient safety, I believe healthcare organizations must have access to accurate, scanner-specific information regarding all significant electromagnetic fields generated by MRI equipment. MRI users are routinely provided with information concerning the static magnetic field and spatial magnetic-field gradients. Comparable information regarding the location and distribution of radiofrequency energy should also be available. Knowledge of RF-field distribution is especially important when evaluating patients with implanted medical devices, conductive materials, monitoring equipment, cables, leads, or other items that may interact with RF energy. Although operating limits such as specific absorption rate and B1+rms are useful, these values do not provide MRI personnel with a complete representation of where RF energy is concentrated or how it is distributed throughout the patient-accessible space. Requiring manufacturers to provide standardized RF intensity and distribution maps would allow MRI medical directors, MRI safety officers, MRI safety experts, technologists, physicists, and healthcare engineers to make more informed risk assessments. This information could improve implant-management decisions, equipment positioning, staff education, emergency planning, and the investigation of RF-related heating events. I encourage the FDA to establish a consistent, understandable, and clinically usable format for these maps and to require that they be provided for both newly marketed MRI systems and existing systems when technically available. The information should address the full patient-accessible volume and relevant transmit-coil configurations rather than only limited or idealized representations. Providing MRI end users with this information would improve transparency and support safer, evidence-based MRI practices. I respectfully urge the FDA to grant the petition.