I did some research in the 60's. As it turns out every element has a signature.
Once that was determined - then compounds were tested and oh what fun - guessing game.

We used a sample with a coil around it. e.g. a 20 turn coil that went to the LNA.
LNA - low noise amplifier - somewhat like on a Dish antenna...

The magnetic field was applied at right angles. This field was swept in RF frequencies.
As the identifying frequency (as the electron of the sample flipped) the LNA
would issue this flipping waveform (to our scope).

Frequency and character determined the signature. It is simply the case of
finding the frequency for the element electron shell to absorb energy. The shell
begins to expand and there is a breaking point where the energy must be flung
off (in Neon it is light - you know that) and the electrons flip as the shells
decrease to normal.

Kinda fun toy - the people connection - was finding the density difference between
the cancer cells to normal tissue and bone. Then sweep around that.

Once a map is determined anything goes - and software was the only holdup.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



John wrote:
Ignoramus13653 wrote:

On 27 Jan 2006 16:18:23 GMT, Dave Hinz wrote:

On Thu, 26 Jan 2006 22:39:58 -0600, Martin H. Eastburn wrote:

And if you go to get an MRI - our bodies might have metal flecks within.
Be sure to mention it - as the metal gets hot and burns.

No, it doesn't get hot or burn. (I worked in engineering on MRI scanners
for ~12 years). It can cause image distortion localized around the
metal (very local effect for slivers, nearly invisible). If you've got
metal in your eyes, they may choose not to use MRI on you, though.

I'd be happy to discuss this in as much detail as you'd like.

Dave, I am interested in MRIs in general, so if you have any stories
to share, or interesting facts, that would be great.

i


They had the theory of MRI's NMR's back in the sixties. The chem lab
was doing research in that area. The big problem was processing the
data with the days technology. They could receive the signals from the
excited molecules but could not do the processing to locate the exact
sorce and make a picture as they do today.

John

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