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Nuclear
Magnetic Resonance (NMR)
Magnetic
Resonance Imaging (MRI)
Nuclear Magnetic Resonance
(NMR) or Magnetic Resonance Imaging (MRI) machines used in the
medical field expose patients to static and time-varying magnetic
fields and radiofrequency fields. The static magnetic
field is similar in nature (but not in intensity) to the magnetic
field encountered from any permanent magnet or the magnetic
field of the earth. Magnetic fields intensities from MRIs are
approximately 2 Tesla or 20,000 gauss. However, higher
magnetic flux densities may be used for limbs, such as 5 Tesla.
For comparison, the static magnetic field of the earth is 0.5
gauss. The frequency of the time-varying magnetic field
is low; less than 75 hertz. The radiofrequency radiation fields
usually range in frequency from 10 and 100 Megahertz. More
research needs to be done in these areas to determine if there
are any adverse health effects from exposure to these devices.
The Department does not
regulate patient exposure to MRIs. N.J.A.C.
7:28-42.1(b) specifically states that that this subchapter
does not apply to the intentional exposure of patients to radiation
for the purpose of diagnosis, treatment or investigation for the
prevention or control of disease. However, exposure to MRI operators
and exposure of the general public to the radiofrequency radiation
fields would be covered by Subchapter 42. While there are
no registration requirements for MRIs which image patients, NMRs
that are used in research are regulated, and must be registered
with the Department as required by N.J.A.C.
7:28-48. For
more information on this topic, please visit the following Internet
areas:
Please read this
Disclaimer
prior to connecting to these websites.
International
MR Safety Central Web Site
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