Electron Spin Resonance (ESR), Nuclear Magnetic Resonance (NMR),

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Electron Spin Resonance (ESR), Nuclear Magnetic
Resonance (NMR), Magnetic Resonance Imaging
(MRI) are covered in Guy ffytche, An
Introduction to The Principles of Medical
Imaging, Imperial College Press, 2000, Chapter 2,
pp 78-88, Chapter 6, pp 199-264. Other coverage
is also found in Smith, Shung, Mosher, Chapter
4, Magnetic resonance imaging, in Shung, Smith,
Tsui, Principles of Medical Imaging, Academic
Press, 1992, pp 213-271.
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Electrons usually occupy electronic shells in
atoms as pairs. In such pairs the electrons have
spins opposite one another so the associated
magnetic fields cancel. In some ions, free
radicals or paramagnetic materials, however, a
single electron may occupy an orbital. Placing
such an atom into a strong magnetic field will
tend to cause the electrons to align with the
field. Adding radiofrequency energy to the
system in this situation can cause the electron
spins to flip so they oppose the magnetic
field. This energy absorption can be detected by
monitoring the energy input as radiofrequencies
are scanned.
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ESR Theory http//www.pharmainfo.net/reviews/ele
ctron-spin-resonance-esr-principle-theory-and-appl
ications
http//www.uottawa.ca/publications/interscientia/i
nter.2/spin.html
http//hyperphysics.phy-astr.gsu.edu/hbase/molecul
e/esr.html
ESR Illustrated http//www.physics.montana.edu/ep
rlab/nBody_2.htm
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Because the exact energy absorption frequency of
the unpaired electrons are sensitive to their
molecular surroundings, the ESR spectra provide
information on the nature of these surroundings.
This is provided both by the position of major
absorbance frequencies by the splitting of
these absorbances into hyperfine spectral
features. While a free radical might have a
characteristic ESR spectrum as a pure isolated
entity, it may demonstrate specific spectral
features when placed into a particular solvent or
biological system.
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Similar to electrons, protons may also
demonstrate quantal spins. If there are odd
numbers of protons in the nucleus, the nucleus
will demonstrate a nuclear magnetic moment
capable of perturbation by radiofrequencies when
in the presence of a strong external magnetic
field. Here, however, the absorbed energy can be
sensed either by the irradiating circuit or by a
field coil as the nuclei flip back to their
ground states. Again, resonant energy levels are
characteristic of the nuclei involved the
molecular environment surrounding these nuclei.
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Nuclei demonstrating accessible signals include
1H, 13C, 17O, 19F, 23Na, 31P
NMR Basics
http//www.cis.rit.edu/htbooks/nmr/
http//www.nobel.se/chemistry/educational/poster/1
991/nmr.html
http//www.wpi.edu/Academics/Depts/Chemistry/Cours
es/CH2670/nmr.html
http//www.brynmawr.edu/Acads/Chem/mnerzsto/The_Ba
sics_Nuclear_Magnetic_Resonance20_Spectroscopy_2.
htm
NMR Software
http//www.spincore.com/nmrinfo/software_s.html
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Basic Instrumental Layout for NMR
http//sis.bris.ac.uk/sd9319/spec/nmrspec.jpg
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NMR Theory http//www.ipfw.edu/chem/262/262spring
03/262nt0311.htm
http//www.shu.ac.uk/schools/sci/chem/tutorials/mo
lspec/nmr1.htm
http//www.nuclear-magnetic-resonance.com/node4.ht
ml
http//www.shef.ac.uk/chemistry/crystal/projects-u
g/sillitoe/html/theory.htm
http//www.resonancepub.com/magres.htm
http//www.avogadro.co.uk/analysis/nmr/nmr.htm
Structural determination of proteins by NMR
http//www.cryst.bbk.ac.uk/PPS2/projects/schirra/
html/home.htm
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Magnetic Resonance Imaging (MRI) is the
extrapolation of NMR to multiple dimensions. It
extracts information on relative composition of
body areas by assessing the strength resonant
frequency ( thus the chemical nature of
absorbing molecules) of the NMR signals as part
of a 3 or 4 dimensional evaluation of objects
tested. The computationally intensive evaluation
of MRI data sorts the vast volume of information
collected during a scan presents it in the form
of an image that includes intensity data.
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MRI basics
http//www.mritutor.org/mritutor/
http//health.howstuffworks.com/mri2.htm
http//www.refindia.net/rlinks/reviewedlinks/mri.h
tm
MRI instrumentation http//info.med.yale.edu/intm
ed/cardio/imaging/techniques/mri_diagram/
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Medical applications http//www.gentili.net/diabe
ticfoot/mri.htm
MRI analysis http//www.cis.rit.edu/research/thes
is/bs/1998/fetzner/Thesis_TF_thesis.html
MRI contrast agents http//www.mritutor.org/mritu
tor/contrast.htm http//www.mr-tip.com/serv1.php?t
ypecoa http//adsabs.harvard.edu/abs/2008mcpp.boo
k..157B
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New Developments Frontiers
Long Range NMR/MRI GloverBowtellMRIridesthewaveNa
ture457n7232p971 BrunneretalTravelingwaveNMRNature
457n7232p994 LongRangeNMRNMeth6p248
Intracellular NMR MRI MidgleyBorkowski2009Elect
ronTomographyHolographynmat2406 BurzShekhtman200
9InsidetheLivingCellNature458n7234p37 Hammel2009Na
noscaleMRINatureCom458p844 InomataEtAl2009HighReso
lutionMultiDimensionalNMRSpectroscopyOfProteinsInH
umanCellsNature458p106 SakakibaraEtAl2009ProteinSt
ructureDeterminationInLivingCellsByInCellNMRSpectr
oscopyNature458p07814