Elektromagnetische Felder

8. Static magnetic fields like those used in medical imaging

• 8.1 What are the sources of static magnetic fields?
• 8.2 What possible health effects of static magnetic fields have been studied?

8.1 What are the sources of static magnetic fields?

The source document for this Digest states:

3.6. Static fields

3.6.1. Sources and distribution of exposure in population

The number of artificial sources of static magnetic fields is small but there is a rapid development of technologies using static magnetic fields. The number of people with implants that can be affected by static magnetic fields is also growing. Static magnetic fields up to some mT are found in certain occupational settings, e.g., in the aluminium and chloralkali industries, in welding processes, and certain railway and underground systems. A very prominent application is MRI: different types of tissue in the human body can be identified and located by using static magnetic fields, magnetic gradients and RF fields. Close to the device a few hundred mT can be reached. Recently developed devices, currently only used by some research and specialised teams for specific applications, can use up to 10 T.

Source & ©: Possible Effects of Electromagnetic Fields (EMF) on Human Health (2007)
Section 3.6 Static fields, 3.6.1 Sources and distribution of exposure in population, p.38

8.2 What possible health effects of static magnetic fields have been studied?

The source document for this Digest states:

3.6.2.Health effects

There are only a few epidemiological studies available and the majority of these have focused on cancer risks. There are some reports on reproductive outcomes, and sporadic studies of other outcomes. Overall, few occupational studies have focused specifically on effects of static magnetic fields and exposure assessment has been poor. In summary, the available evidence from epidemiological studies is not sufficient to draw any conclusions about potential health effects of static magnetic field exposure (Feychting 2005b).

A large number of biological studies have been carried out in an effort to detect biological effects of static magnetic fields. The studies include in vitro and in vivo laboratory studies as well as studies on human volunteers. This research has been reviewed comprehensively in UNEP/WHO (2006). Known effects of magnetic fields are orientation of forces applied on biological molecules with magnetic properties: haemoglobin, rhodopsin (visual pigment), free radicals, nitric oxide; these effects are detectable at field levels of about 1 T, without known health consequences.

3.6.3.Conclusions about static fields

Adequate data for proper risk assessment of static magnetic fields are almost totally lacking. The advent of new technology, and in particular MRI equipment, makes it a priority for research.

Source & ©: ,  Possible Effects of Electromagnetic Fields (EMF) on Human Health (2007)
Section 3.6 Static fields, 3.6.3 Conclusions about static fields, p.38