MRI hardware Superconducting magnet

Magnetic fields greater than 0.5 T can only be generated by extremely heavy electromagnets or by much lighter superconducting magnets. Superconducting magnets are almost universally preferred. Ancillary equipment includes the liquid-helium cooling systems required to keep the temperature low enough (4 K) for superconduction. Cooling consumes the majority of the supplied power. Only a small current is initially required to generate the field, which is then self-sustaining.

Small variations in the homogeneity of the magnetic field give rise to distortions and artefacts. The field is minutely adjusted to improve homogeneity using additional magnets in an automated procedure known as shimming.

Magnetic field gradients are essential to MRI. Rapid switching of gradient coils produces the loud 'knocking' sound associated with magnetic resonance scanners. However, three orthogonal gradients are available which are coupled to generate gradients in any direction.

Break Free From Passive Aggression

Break Free From Passive Aggression

This guide is meant to be of use for anyone who is keen on developing a better understanding of PAB, to help/support concerned people to discover various methods for helping others, also, to serve passive aggressive people as a tool for self-help.

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