Re: MRI Machines
- From: "Bob Eld" <nsmontassoc@xxxxxxxxx>
- Date: Tue, 24 Jun 2008 13:09:43 -0700
"Joerg" <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:yrb8k.14317$Ri.3019@xxxxxxxxxxxxxxxxxxxxxxx
Jim Thompson wrote:me
On Tue, 24 Jun 2008 11:34:07 -0700, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Tue, 24 Jun 2008 13:28:46 -0400, RFI-EMI-GUY
<Rhyolite@xxxxxxxxxxxx> wrote:
Well I spent a half hour of my life under the magnet of an "open" MRI
machine yesterday. Still a bit claustrophobic. While I sort of
understand the theory of the MRI, what I don't understand is what
creates all the noise and racket. Any experts out there that can tell
whats going on?Pulsed gradient coils. These are "small" 3-axis coils that sweep a
gradient field across your innards, modulating the nuclear resonant
frequencies of your molecules to produce the spatial resolution. These
are generally water-cooled, with ballpark 20 KW constant-current
drivers per axis, playing all sorts of weird waveforms.
They scanned my head last year, with the gradient coils around my head
like some horror mask: noisy and boring.
John
A few years ago they scanned my sinuses.
I must admit a claustrophobic feeling also :-(
That's probably because you guys don't have a house with a narrow crawl
space. At least you can be sure that there won't be critters such as
rattle snakes waiting inside that MRI tube.
--
Regards, Joerg
http://www.analogconsultants.com/
I had a rattle snake in my garage a couple of weeks ago.
.
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