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Into the Future with Metrology - The Challenges of Medical Technology

Diagnostics and Therapy

MRI – safety first!

Torso phantom
Torso phantom with a wire in the "shoulder", together with a current sensor within the 3-tesla MR scanner of PTB.

With well over 100 million examinations per year worldwide, magnetic resonance imaging (MRI) is the second most important medical imaging method (after X-rays). MRI provides sharp 3D images with a resolution down to the sub-millimeter range while being non-invasive and radiation-free. The trend is towards higher magnetic fields. These allow sharper images to be produced, but due to the higher RF frequency, tissue heating may be more severe. This might become a problem for the 8 to 10 percent of Europeans who have medical implants in their bodies, for example an artificial hip joint or a pacemaker. Therefore, especially in the case of the latest 7-tesla ultra-high field MRIs, which are currently in the clinical test phase, the electromagnetic fields applied to the patient must be measured reliably. PTB is developing measuring instruments for this, for example MR-compatible current sensors for monitoring the RF heating of wire-like implants, or special MR-safe devices for generating well-defined electromagnetic fields for the in situ calibration of RF field probes. With these new methods, the electromagnetic fields can be determined in a traceable manner. In addition, special body phantoms as well as simulation methods are being developed for comprehensive safety assessments of MRIs. In this way, PTB spans the whole range of metrology for the safety of MRI.

 

Department involved

Opens internal link in current window8.1 Biomedical Magnetic Resonance