Subject:  Re MRI technical question (Cook)(Smith).
Date:     Mon, 23 Oct 2000 094007 -0500
From:     Roy Beavers 
To:       guru 
--------------------------------------------------

.........Response from EMF-L......

Pleased to hear again from Dr. Smith --  one of the EMF pioneers --
now in retirement........guru......

-------- Original Message --------
Subject: Re: MRI technical question (Cook).
Date: Mon, 23 Oct 2000 14:06:21 +0100
From: "Cyril W. Smith" 
Reply-To: cyril.smith@which.net
To: Andrew Cook 
CC: roy@emfguru.com
References: <39EDF4A4.C88564E0@emfguru.com>

Dear Andrew Cook,

I have noted your question to 'emfguru' of October 18. You are correct
about the proton NMR in the geomagnetic field. In technology, it is
necessary to use higher magnetic fields and frequencies for NMR work
because of detector sensitivity limitations. If these constraints do not
apply to living systems, and the theoretical implications of this are
profound, then the 42.58 MHz/T ratio for NMR scales over all field
strengths quite generally. 

The first evidence in support of this was a blip at 2 kHz in some raw
data for dielectrophoresis experiments presented by Professor Herbert
Pohl at a conference in Oxford University in the early 1980's. I  and my
students did work on this topic and we published a review in "Modern
Bioelectricity" Marino A.A.(Ed) New York: Marcel Dekker (1988) Chap.4,
pp.75-104 and also as "Dielectric measurements on live biological
materials under magnetic resonance conditions" in J. Biol. Phys. 11:
15-22 (1983).

There are bio-effects under NMR conditions but this topic forms a closed
set of phenomena  not of general applicability to the bio-effects and
bio-hazards of EMF's discussions except in the cases of microwave
induced cataracts in bovine eye lenses and hydrolytic enzyme reactions.

Yours sincerely,


Cyril Smith.


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Reprinted with permission of Roy Beavers, http://www.emfguru.com