Radio Logic,
Incorporated
P. 0. Box
9665, New Haven, CT 06536 (203)624-8113
Mr. Murray Barlowe,
WA2PZO
SCIENCE WORKSHOP
BOX 310 BETHPAGE NY 11714
(516) 731-7628
Dear Murray,
Nuclear
Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI)
employs high
frequency radio transmitters, receivers, and computer science techniques
to generate images or chemical spectra of organic materials. NMRIMRI techniques
use methods developed between 1930 and 1945 for military RADAR. RADAR and
NMR/MRI both
use Transmit/Receive circuits, state of the art receiver sensitivity, and
good antenna (probe) design.
NMR/MRI applications
using radio frequency methods have not received much
attention in
the amateur radio publications (Ham Radio, QST, CQ , and 73) since these
publications are concerned with radio communications as an end use of RF
techniques. There are a whole score of "non-communications" usage of RF
techniques and
NMR/MRI would
be one such use. You can "listen" to the radio signals produced by the
nucleus of the hydrogen atom by exciting these photons to transmit, and
make an image by reconstructing the matrix of protons. The technical challenge
of building a system to do this might seem worth while to experienced amateurs.
The transmitter
modulation required for selective excitation of a group of protons
can be accomplished
by using techniques similar to the early days of single sideband
modulation,
using phasing (audio multiplication by RF) techniques. The Science Workshop
"Poor Man's Spectrum Analyzer" provides a useful instrument to adjust the
required circuits to assure a correctly aligned phasing-type SSB transmitter.
No, the protons do not mail QSL cards, but the thrill of capturing a Free
Induction Decay might serve as a substitute. All that is required is lots
of patience and visits to flea markets, a few books on the subject, a large
magnet, and determination.
I have been building
simple NMR systems since 1957, first using the earth's
magnetic field
as a free proton magnet source. Since 1982 I have been a part of the technical
support team at Yale's NMWMRI instrument group, certainly the most enjoyable
time I have had using short wave techniques since getting my original ticket
in 1938 (WSIMB).
I am unaware
of any amateur magnetic resonance interest or support group at
this time, but
this would be a way of developing and sharing techniques and problems.
Sincerely,
Wade G. Holcomb, WIGHU