User's Manual

Fields Most serious hazards
Static magnetic field Movement by implants and prostheses in the body
Attraction, alignment, and projectile-like acceleration of magnetizable
objects
( Page 18 Safety instructions on the static magnetic field)
Gradient fields Peripheral nerve stimulation
( Page 20 Safety instructions on RF and gradient fields)
RF fields Warming of body tissue
( Page 20 Safety instructions on RF and gradient fields)

All persons (e.g. patients, physicians, operating and cleaning
personnel, accompanying persons, and rescue personnel/fire
fighters) are exposed to these fields in the examination room.
Therefore, all limits and safety measures regarding
electromagnetic fields equally apply to patients and MR workers.
◆ Observe prohibition signs in the area near the entrances to the MR
system and the controlled access area.
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
0.5 mT. 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.
Static magnetic field/controlled
access area
Gradient fields
RF fields
Safety 2
MAGNETOM Skyra
fit
| syngo MR E11
17
Print No. M6-04401.621.02.02.02