--- In FairfieldLife@yahoogroups.com, "authfriend" <jstein@...> wrote: > > --- In FairfieldLife@yahoogroups.com, "sparaig" <LEnglish5@> wrote: > > > > Most brain imaging techniques are actually very dangerous. > > There are "cooling off periods" measured in weeks or even > > a month or more, before a second test can be performed, > > except in emergencies. This is because they are extremely > > intrusive, by nature, involving the ingestion of toxic > > and/or radioactive substances, and/or the use of power > > levels so great that they cause overheating in the brain. > > Lawson, I don't think this is accurate. fMRI, for > example, uses no radioactivity or tracer substances > and is completely nonintrusive/noninvasive. MRI only > occasionally uses contrast agents for particular > purposes. PET scans do use ionizing radiation and > radiolabeled contrast agents, however. > > I looked up a bunch of techniques on Wikipedia, and > none of the articles said anything about "cooling off > periods," although each had a section on risks. Same > with overheating in the brain. Nor could I find > anything about any of them requiring many minutes to > establish an image. > > Maybe I missed something somewhere, but I think you're > way overgeneralizing. > >
Well, fMRI is considered one of the safest of the imaging techniques, IIRC: http://www.mrisafety.com/safety_article.asp?subject=17 L.
