The subacute risks and side effects of magnetic and RF fields (for patients and staff) have been intensively examined for a long time, but there have been no long-term studies following persons who have been exposed to the static magnetic fields used in MRI. However, no permanent hazardous effects of a static magnetic field exposure upon human beings have yet been demonstrated.
Temporary possible side effects of high magnetic and RF fields:
The results of some animal and cellular studies suggest the possibility that electromagnetic fields may act as co-carcinogens or tumor promoters, but the data are inconclusive. Up to 45 tesla, no important effects on enzyme systems have been observed. Neither changes in enzyme kinetics, nor orientation changes in macromolecules have been conclusively demonstrated.
There are some publications associating an increase in the incidence of leukemia with the location of buildings close to high-current power lines with extremely low-frequency (ELF) electromagnetic radiation of 50-60 Hz, and industrial exposure to electric and magnetic fields but a transposition of such effects to MRI or MRS seems unlikely.
Under consideration of the MRI safety guidelines, real dangers or risks of an exposure with common MRI field strengths up to 3 tesla as well as the RF exposure during the MRI scan, are not to be expected.

For more MRI safety information see also Nerve Conductivity, Contraindications, Pregnancy and Specific Absorption Rate.

See also the related poll result: 'In 2010 your scanner will probably work with a field strength of'

From Hitachi Medical Systems America, Inc.;
because of its dependability, the MRP-7000â„¢ remains popular more than a decade after the first U.S. system was shipped. This system maintains a high resale value, what has made it one of the most sought-after scanners on the used MRI equipment market.

A magnet is by definition an object with magnetic properties (magnetism) that attracts iron and produces a magnetic field. It can be a permanent magnet or an electromagnet.
Permanent magnets do not rely upon outside influences to generate their field. In permanent magnets are the atoms and molecules ordered in long range. The specific electron configuration and the distance of the atoms is what lead to this long range ordering. The electrons exist in a lower energy state if they all have the same orientation. Magnetic domains can be likened to microscopic neighborhoods in which there is a strong reinforcing interaction between particles, resulting in a high degree of order. The greater the degree of ordering within and between domains, the greater the resulting field will be. Long range ordering is one of the hallmarks of a ferromagnetic material.
A current carrying conductor for example a piece of wire, produces a magnetic field that encircles the wire. An electromagnet, in its simplest form, is a wire that has been coiled into one or more loops. This coil is known as a solenoid. The more loops of wire and the greater the current, the stronger the field will be.
Superconducting magnets are a special type of electromagnets, often used in MRI machines with high field strength.

Oblique imaging generates images along oblique orientations between the conventional planes.

An artificial object of known size and composition that is imaged to test, adjust or monitor an MRI systems homogeneity, imaging performance and orientation aspects. A phantom is usually a fluid-filled container or bottle often filled with a plastic structure of various sizes and shapes.

See also Daily Quality Assurance.