Apparently, many parents are concerned about the possible impact of strong magnetic fields on children, and are unwilling to allow their children to get MRI scanned for research purposes; the article reports on two Chinese neuroscientists who were unable to find healthy children to volunteer for their MRI studies.“I would not dare to allow my children to be tested by MRI,” says radiologist Han Hongbin of Peking University Third Hospital. “Nobody can ensure that there is no potential danger,” such as during nonroutine MRI scans that use extremely powerful magnetic fields, he says.This is not a problem I've heard of amongst Western researchers, but on the other hand, it's not all that bizarre. In Britain, and as far as I know elsewhere too, standard practice is never to include women who are (or might be) pregnant in fMRI studies. This is not because strong magnetic fields have any known risks for unborn babies, or indeed anyone else. It's purely a better-safe-than-sorry precaution. But it sounds as though the concerns of Chinese parents are of that kind as well.
MRI safety is an interesting topic. Used incorrectly, an MRI scanner could, in theory, harm you in quite a few ways, from heating you up due to radiofrequency energy transfer, to stopping your heart by inducing an electric current in it (although I don't think that's ever actually happened, it is a theoretical concern). Fortunately, by sensible selection of the scan parameters, these risks can be avoided.
The only real danger is that posed by metal objects (specifically ferromagnetic ones), which in the presence of a strong magnetic field become deadly projectiles. This is why it's a bad idea to carry that pair of scissors into the scanner room. Remember: the magnet is always on...
11 comments:
Presumably they can rip your pacemaker out. And reprogram it somewhat.
The magnetic part doesn't bother me, but there used to be something called "nuclear magnetic resonance", which sounds creepy toxic. I wouldn't even go into a building where there was any of that stuff around.
This fear is likely due to the philosophy of "chi" in Chinese medicine, which is often compared to a magnetic field. Since chi is thought of as the life force, messing with one's life force with powerful magnets is surely thought to lead to dangerous consequences.
Pregnant women are never used as healthy volunteers, but there are actually some fetal fMRI studies and quite a few fetal MRI studies. The original ones were in Europe and they're much more common there, but some fetal MRI studies are now in the US.
If you do a google scholar search, quite a few UK studies appear.
You can find a list of studies on MRI safety at
http://www.mrisafety.com/research_summary.asp
in general I see no obvious findings on adverse effects of the magnet... but
"at 4 T... in 97% of the trials the rats would not enter the magnet"
"little, if any, damage to male reproductive tissues from...high intensity MRI exposure"
so, who knows ;)
;-)
Duff: I hadn't thought of that... could be. The Science article also mentions that the distrust of MRI could be part of a more general distrust of doctors that's emerging in China... although unfortunately they don't go into much detail.
Roger, I dunno if it's the nuclear bit that scares people. Try saying "You need an NMR" really fast and watch people's eyes widen...
yarikoptic: "little, if any, damage to male reproductive tissues from...high intensity MRI exposure"
Ooo-er, I don't like the sound of that. Even if it's only a little. Maybe someone should take a closer look at this footage and see if they can see any signs of problems...
Especially in Bahston, Chris.
Not without a precedent...
In the 1950's in the UK, Alice Stewart expressed concerns about connection between Xrays exposure during pregnancy and childhood cancer, only to be ridiculed by her colleagues and her research was dismissed. One of the colleagues called her senile: how could Xray radiation cause cancer in unborn babies? Radiologists and obstetricians kept zapping mothers until the late 70's when enough data accumulated to proof Stewart's research was correct, there was direct connection btwn the two.
Now we hear that MRI is harmless. When general public is skeptical, can we blame it?
Hello. Thank you for your writing.
I was unsure of something this old being bumped but feel I have another angle to this.
I do not know what the Chinese understand as they become more westernized but just not knowing is enough to keep me away from such a big glowing room with a buzzing machine and men and women in white coats.
Although none of this was documented at the time hindsight has taught me something .
When I was in my twenty's ,after an accident I was scheduled for a a scan at a V.A. Hospital in the U.S. I waited in the hall then was moved to chairs in "the room" almost immediately upon sitting down I started having strong sensations, feelings my tastes my hearing the smells the flickering light and that just over all feeling of dread and then the left side of body going completely numb.
I had experienced this "feeling" for years so I had no reason to tell anyone. I progressed and was laid up for the scan and as soon as the machine was turned on I floated slightly above the table and lost all feeling in my left side and my eye flickered .
I do not remember much else and was "asleep" for around 3 minutes.
Hindsight and several years of trying to understand my mind and body has taught me those were seizures and the first feelings I had were auras and the next what I refer to as a partial seizure.
The point is just being around the magnet set me into seizure.
There are 10,s of thousands of undiagnosed people being exposed this way .
It just leaves me wondering what happens to them when they have an m.r.i. and have a gran mal seizure on the table do they get treated for both conditions or the seizures are ignored ? Rick
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