What is it about lower fields that means you cannot get a good image? Interference? Tissue movement in longer exposures? Why can't the device just integrate over a longer period of time?
It's just the physical reality of nuclear magnetic resonance. SNR scales with B^(3/2), since the signal scales with B^2 and the noise scales with root B.
This means going from 0.05T to 1.5T boosts your sensitivity ~150x. Measurement time scales with sensitivity^2, so you'd have to measure 20k x longer.
This means going from 0.05T to 1.5T boosts your sensitivity ~150x. Measurement time scales with sensitivity^2, so you'd have to measure 20k x longer.