The static basic field is generated by a superconductive magnet and
may extend beyond the examination room (walls, ceilings).
In order to minimize the hazards mentioned, the controlled access
area of the basic field is identified on the floor (0.5 mT line). Outside
the controlled access area, the magnetic flux density is less than
0.5mT. See: System owner manual
Linearly rising additional fields of variable strength - gradient fields -
are superimposed on the static main magnetic field in three different
orientations. They may cause shifts in charge in the patient's tissue
and lead to peripheral nerve stimulation.
The nuclear spins of the body tissue are stimulated via pulsed
electromagnetic RF fields. These RF pulses are generated by an RF
transmit amplifier and transferred via RF coils to the object to be
measured.
RF fields lead to warming of the body tissue. In this context, an
important value per body weight is the specific absorption rate or
SAR. ( Page 113 Physiological effects)
Possible undesirable side effects for MR are dizziness, heating,
claustrophobia and nerve stimulation.
Safety instructions on the static magnetic field
The list of objects in this chapter is not exhaustive. It only serves as an
illustration of objects that present hazards in the presence of
magnetic forces.
◆ Only use equipment specified or recommended for use in the
controlled access area.
Static magnetic field/controlled
access area
Gradient fields
RF fields
Side effects
2.2.2
Safety 2
MAGNETOM Avanto, MAGNETOM Verio | syngo MR E11
19
Print No. MR-01501G.621.02.02.02
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