User:Kbmathieu/sandbox

Magnetic relaxometry or magnetorelaxometry (MRX), also referred to as nanomagnetic relaxometry (NanoMRX) or superparamagnetic relaxometry (SPMR), is a technique that detects the relaxation properties of superparamagnetic iron oxide nanoparticles (SPIONs) in response to a brief magnetizing pulse. Ultra-sensitive magnetometers, such as superconducting quantum interference devices (SQUIDs), fluxgate magnetometers, or atomic magnetometers, are used to measure the resulting relaxation. Characteristic temporal differences in magnetic relaxation behavior can be used to distinguish free (unbound) SPIONs, which relax relatively quickly after the magnetic field is turned off by Brownian motion, from bound (or sufficiently immobilized) SPIONs, which relax at a much slower rate by Néel relaxation.

Should I discuss different magnetometers (SQUID vs fluxgate vs atomic magnetometers?)....http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3389787/ ; https://www.researchgate.net/profile/Dietmar_Eberbeck/publication/216212881_Magnetorelaxometry_of_magnetic_nanoparticles_with_fluxgate_magnetometers_for_the_analysis_of_biological_targets/links/56405b7e08ae45b5d28d3bf9.pdf

History
http://link.springer.com/chapter/10.1007/978-1-4612-1260-7_160 http://iopscience.iop.org/article/10.1088/0953-2048/12/11/377/pdf http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=783791 http://www.maschinenbau.tu-ilmenau.de/mb/wwwtd/hydromag/ferro/conferences/workshops/benediktbeuern/pdfs/weber.pdf http://www.personal.uni-jena.de/~p5stpr/Homepage/English/Files/ICMF9_MORFF_Abstract.PDF

Applications
It is important to note that there are ex vivo applications which also include SPION characterization and have a little bit different focus than the in vivo applications...

binding between targeted iron oxide nanoparticles and cancer cells or tumor vessels.

The utilization of MRX for a variety of applications has been explored, including breast cancer detection in mice, detecting minimal residual disease in leukemia patient bone marrow biopsies, and quantifying nanoparticle accumulation in biological samples; however, it has not yet achieved clinical translation.100, 101,102-109

Safety
In vivo MRX applications rely on injection of SPIONs, which are considered to be non-toxic. In fact, several SPION agents have achieved FDA approval including Feridex and Resovist (make sure there was not safety concerns with these). Briefly describe how SPIONs are filtered out of the body (RES)

Thus, one potential contraindication for SPION administration is hemochromatosis. Patients with hemochromatosis have excess iron accumulation, most of which is retained in the liver, and are typically advised to avoid supplemental iron.

http://pubs.acs.org/doi/abs/10.1021/cr2002596 http://www.sciencedirect.com/science/article/pii/S0169409X1000133X http://www.ajronline.org/doi/pdf/10.2214/ajr.152.1.167 http://cdn.intechopen.com/pdfs-wm/47183.pdf http://www.microbecolhealthdis.net/index.php/nano/article/viewArticle/5358

Comparison with other technologies
I think all of the technologies below rely on magnetic shielding? - Do the Germans use shielding? This is one advantage of MRX

Also important to note that MRX is not currently an imaging technology unlike the rest (although MEG being an imaging technology is a little questionable).

MRI
Magnetic resonance imaging (MRI)

"In clinical and research MRI, hydrogen atoms are most-often used to generate a detectable radio-frequency signal that is received by antennas in close proximity to the anatomy being examined... Pulses of radio waves excite the nuclear spin energy transition, and magnetic field gradients localize the signal in space. By varying the parameters of the pulse sequence, different contrasts can be generated between tissues based on the relaxation properties of the hydrogen atoms therein. " "MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field. When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the protons realign with the magnetic field. The time it takes for the protons to realign with the magnetic field, as well as the amount of energy released, changes depending on the environment and the chemical nature of the molecules. "

MPI
Magnetic particle imaging (MPI)

Like MRX, MPI is only detecting SPIONs. Unlike MRX, MPI detects SPIONs regardless of their binding status.

MEG
magnetoencephalography (MEG)

MEG uses SQUIDS.

http://link.springer.com/chapter/10.1007/978-3-642-33045-2_48

Does MEG use shielding?

Commercialization
The MRX technology was first commercialized for in vivo use by Senior Scientific LLC, which was founded in 200? in Albuquerque, NM by Dr. Edward Flynn. In 2014, Senior Scientific deployed their first magnetic relaxometry instrument outside of an industrial setting within the research laboratory of Drs. John Hazle and Kelsey Mathieu at The University of Texas MD Anderson Cancer Center in Houston, TX. In 2016, a second magnetic relaxometry instrument was placed in Dr. Brian Ross' laboratory at the University of Michigan Medical School in Ann Arbor, MI. Senior Scientific also manufactures PrecisionMRX® 25-nm magnetite (Fe3O4) SPIONs to be used in conjugation with their magnetic relaxometry instruments.

There may have been commercialization of a tabletop magnetic relaxometry instrument in Germany, but it is unclear...