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The reason for huge magnets is to drown out effects of external magnetic fields which would otherwise cause spatial uncertainty. For me this seems like somethin
by dfox 7y ago
The reason for huge magnets is to drown out effects of external magnetic fields which would otherwise cause spatial uncertainty. For me this seems like something that can be partially compensated for in software postprocessing given fast enough scan rate.
- amluto 7y agoThe magnetic field is to shift the energy levels of the nuclear spin states. The transition energy is proportional to the applied field, and the wavelength of the RF field used for imaging is inversely proportional to the energy. So a stronger field gives a smaller wavelength and thus higher resolution.
- exikyut 7y agoOooh, in the same way that the higher 5G frequencies don't travel as far!
- ska 7y agoThis is really not correct. External fields are tiny relative to these fields, you have bigger issues with coupling and eddy currents. It’s not quite as simple as field strength equals resolution, but generally it is easier to achieve high resolution with higher main field strength. See for example mouse scanners at 12T