4 ms·
I thought they had to turn the magnet on and off. This would first align all the magnetic moments of the specific atoms and then as they randomize when the fiel
by bawana 7y ago
I thought they had to turn the magnet on and off. This would first align all the magnetic moments of the specific atoms and then as they randomize when the field is off, they interfere with a superimposed radio field creating peaks and troughs. Tomographic calculations are then applied to the collected radio signals to give an image. How can a permanent magnet be used?
- rrss 7y agoThere are a lot of NMR imaging techniques, and I'm not an expert, but my understanding (based on discussion with experts) is that the main magnetic field is static during all MRI scans. The gradient fields from electromagnets change, though, to alter the Larmor frequency across the thing being imaged.
- SubiculumCode 7y agoThe field is always on. Safety first. :)