crasch (crasch) wrote,

80 NM MRI resolution achieved

Via mauitian:

[Update: This advance has important implications for cryonics and human longevity, by bringing us much closer to being able to scan the brain at atomic level resolution. Your personality and memory are dependent upon the connections made by the neurons within your brain, which are in turn determined by the patterns of atoms which make up those neurons. Right now, human brains have no redundancy or backup capability -- if a blood clot blocks an arteriole for a 10 minutes or so, that's it, you're dead.

However, what if you could scan the human brain at the atomic level? And what if the rate of increase of computing power continues on it's current trajectory? At some point, in principle, it should be possible to simulate, in silico, your brain. If you're a cryonics patient, your frozen brain could be then scanned, and you could be revived. Or, if scanning and simulation advance fast enough, your brain could be backed up while you were still alive. You would then have an effectively unbounded lifespan, as killing you would require not just destroying your "active" brain, but all of the backups as well. ]

The American Institute of Physics Bulletin of Physics News
Number 680 April 8, 2004 by Phillip F. Schewe, Ben Stein

MRI WITH 80-NM RESOLUTION, far better than for the best medical
scans, has been achieved with a device that combines atomic force
microscope (AFM) and nuclear magnetic resonance (NMR; also known as
magnetic resonance imaging, or MRI) technology. In the hybrid
methodology called magnetic resonance force microscopy (MRFM), a
tiny magnetized particle is attached to a cantilever which is then
brought near a sample which surrounded by a coil that emits radio
waves. When a tiny magnetic domain in the sample feels just the
right amount of magnetic field from the nearby coil and magnetic
particle it will vigorously interact with them resonantly. (The
tiny volume being probed is referred to as a voxel, and the
sample-coil-particle combination is equivalent to the setup in a
standard MRI machine for imaging, say, a tumor.) The
sample-particle resonant interaction causes the cantilever to
oscillate (the particle on the cantilever is like a man bouncing
resonantly, higher and higher, on a diving board). The oscillating
cantilever, monitored with a laser beam, is then scanned from place
to place, filling out a two-dimensional and then a three-dimensional
map of the resonant interaction. (The scanned, oscillating
cantilever plus laser readout is the AFM part of the setup.) The
goal is not to help surgeons (the best medical MRI has a spatial
resolution of about a tenth of a millimeter) but to be able to scan
and image small objects---especially particles of biological
importance, such as viruses and proteins---with atomic-scale
resolution. In other words, you would like to increase the
sensitivity so as to map the presence of single spins. The voxel in
this case would be shrunk to less that than 1 nm.
A new experiment at the University of Washington is far from
reaching this goal, but researchers have improved sensitivity by a
factor of almost 10,000 from the time of the earliest MRFM imaging
papers in 1996. (For a report from 1997, see
The higher sensitivity in general comes by shrink the apparatus and
cooling things (currently, to 80 K) as much as possible, the better
to read out the oscillations and position the sample with greater
accuracy. The Washington voxel of 80 nm---how big is it? One of
the team members, John Sidles (206-543-3690, s says that about a million of these voxels
could fit inside a typical blood cell. (Chao, Dougherty, Garbini,
Sidles, Review of Scientific Instruments, May 2004; website, ) Other groups are working in
this area and are attempting to marshal the requisite equipment
needed for single-spin imaging. According to Joseph Shih-hui Chao,
one of the authors, this would include millikelvin temperatures,
30-nm-sized magnetic particles, sub-nm positioning accuracy, and
yet softer cantilevers.
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