Magnetic Fields Flashcards
When is acoustic noise generated?
As current is passed through the gradient coils during image acquisition
What is the main magnetic field responsible for?
the alignment of nuclei
Is the main magnetic field static or dynamic?
static
Are there long-term biological effects of magnetic fields?
no
What type of effects have been observed on human subjects exposed to 2T and above?
some reversible biological effects (fatigue, headache, hypotension, irritability)
Why shouldn’t fire fighters enter a magnet room until quench is proven in the event of a fire?
breathing tanks can be ferromagnetic and can cause serious injury
What is the fringe field?
magnetic field outside of the bore
What force is responsible for ferromagnetic objects being violently attracted into the scanner?
translational force
What force is responsible for moving/twisting when entering the bore of the magnet?
rotational force
Is steel ferrous?
yes
What objects are used as an adunct to verbal screening?
metal detectors and hand held magnets
What poses damaging effects including: torque, heating, and artefacts on MR images?
metallic implants
