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 ONI Medical Systems, Inc.;
MSK-Extreme™MRI system is a dedicated high field extremity imaging device, designed to provide orthopedic surgeons and other physicians with detailed diagnostic images of the foot, ankle, knee, hand, wrist and elbow, all with the clinical confidence and advantages derived from high field, whole body MRI units. The light weight (less than 650 kg) of the OrthOne System performs rapid patient studies, is easy to operate, has a patient friendly open environment and can be installed in a practice office or hospital, all at a cost similar to a low field extremity machine.
New features include a more powerful operating system that offers increased scan speed as well as a 160-mm knee coil with higher signal to noise ratio, and the option of a CD burner.

Manufactured by Esaote S.p.A.;
a low field open MRI scanner with permanent magnet for orthopedic use. The outstanding feature of this MRI system is a patient friendly design with 24 cm diameter, which allows the imaging of extremities and small body parts like shoulder MRI. The power consumption is around 1.3 kW and the needed minimum floor space is an area of 16 sq m.
At RSNA 2006 Hologic Inc. introduced a new dedicated extremity MRI scanner, the Opera. Manufactured by Esaote is the Opera a redesign of Esaote's 0.2 Tesla E-Scan XQ platform, which now enables complete imaging of all extremities, including hip and shoulder applications. 'Real-time positioning' reportedly speeds patient setup and reduces exam times.
Esaote North America and Hologic Inc are the U.S. distributors of this MRI device.

From Toshiba America Medical Systems Inc.;
the Ultra™ system was developed to help healthcare providers be more competitive by delivering greater patient comfort and a broad range of clinical capabilities, says Anita Bowler, product manager, MRI Business Unit, Toshiba America Medical Systems Inc With its unique, powerful gradient technology, the Ultra™ performs advanced clinical studies and consistently provides high-resolution images that are typically associated with high field MRI systems. At the same time, the Ultra™ offers a truly open feeling that makes patients more relaxed, especially those with claustrophobic tendencies.

From Hitachi Medical Systems America Inc.;
the AIRIS II, an entry in the diagnostic category of open MR systems, was designed by Hitachi Medical Systems America Inc. (Twinsburg, OH, USA) and Hitachi Medical Corp. (Tokyo) and is manufactured by the Tokyo branch. A 0.3 T field-strength magnet and phased array coils deliver high image quality without the need for a tunnel-type high-field system, thereby significantly improving patient comfort not only for claustrophobic patients.