- Medical Imaging

MRI and NMR

(Nuclear) Magnetic Resonance Imaging & Magnetic field strength

We are made around 60% of water and each water molecule has 2 hydrogen atoms, 2 hydrogen nuclei or let us say 2 protons.The gyromagnetic ratio of hydrogen is 43MHz/T. That means that in the earth magnetc field of 50μΤ our protons precess or wobble at 2.15Hz. However, their axes are found in random orientations. When we are in an MRI field of 1T the protons axis align to the direction of the magnetic field and precess at 43MHz. If we provide electromagnetic radiation of 43Hz, they will absorb it and re-emit it and because different areas will absorb it to different degrees we will have an image with different intensities on a gray scale.

However contrary to the common belief, NMR Imaging is not necessarily performed with very strong magnetic fields; it can also be performed in the Earth magnetic field. Here is a related study:

http://onlinelibrary.wiley.com/doi/10.1002/mrm.1910150305/abstract

And another one:

http://www.fmf.uni-lj.si/~stepisnik/obj_clanki/StepisnikPhysicaMedica90.pdf

Also:

Earth's field NMR
https://en.wikipedia.org/wiki/Earth's_field_NMR

Becker, the Body Electric

p297

"Magnetic resonance (NMR) is induced in the atoms of the DNA molecules. In simplified terms, nuclear magnetic resonance is present when the magnetic fields around atomic nuclei are induced to vibrate in unison. The phenomenon requires two external magnetic fields, one steady and one pulsating. For every chemical element, the oscillating field at a specific frequency will induce resonance within the steady-state field at a certain strength. In 1983 a research team under A. H. Jafary-Asl showed that the earth's magnetic background could serve as the steady field, while the harmonics of power line frequencies could produce a time-varying field that would induce nuclear magnetic resonance in at least two common atoms of living tissue—potassium and chlorine. Other elements might also be susceptible to the effect. Bacteria and yeast cells exposed to these NMR conditions doubled their rate of DNA synthesis and proliferation, but daughter cells were half size. Liboff, analyzing contradictory studies, found that the contradictions disappeared when he calculated resonance conditions for the earth's field where each test was done. Previous work must now be reinterpreted as one vast experiment in adding new frequencies to the varying background. "

What we can and cannot (yet) do with functional near infrared spectroscopy

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033094/

Quantum dots for high-resolution brain imaging

Link

Ultrasound on a chip

Link cf News Section

Hemoglobin & fMRI

‘Mind reading’ technology identifies complex thoughts, using machine learning and fMRI

http://www.kurzweilai.net/mind-reading-technology-identifies-complex-thoughts-using-machine-learning-and-fmri

Fitbit Heart Sensor

https://www.fitbit.com/uk/technology

Explore the technology > How photoplethysmography works

Determination of a volumic change using green light absorbed by blood

Holographic imaging with Wi-Fi

"Scientists have developed a holographic imaging process that depicts the radiation of a Wi-Fi transmitter to generate three-dimensional images of the surrounding environment."

https://www.sciencedaily.com/releases/2017/05/170504110559.htm

Link shared by Suja Vijayan

(Image from Phys. Rev. Lett.)

Wearable MRI

"I figured out how to put basically the functionality of an M.R.I. machine — a multimillion-dollar M.R.I. machine — into a wearable in the form of a ski hat," Jepson tells CNBC, though she does not yet have a prototype completed.

"Fabric lined with flexible LCDs with the functionality of MRI in a wearable with comparable resolution."

http://www.cnbc.com/2017/07/07/this-inventor-is-developing-technology-that-could-enable-telepathy.html

"We can with infrared light put voltage down a neuron" - Infrared red light at a read and write function

Excerpt from link below: "Right, or you can read it and write it. You can change neuron state. We know infrared is keeping neurons alive. We know that IR light activates the neurons without using optogenetics, which is this breakthrough of putting a chemical that binds to a neuron so that it changes color. Then you can put a voltage down it. We can, with IR light, put voltage down a neuron."

https://www.recode.net/2017/3/30/15130136/transcript-mary-lou-jepsen-one-laptop-per-child-too-embarrassed-to-ask-live-sxsw

Mind reading methods

http://www.kurzweilai.net/mind-reading-technology-identifies-complex-thoughts-using-machine-learning-and-fmri

fMRI and machine learning: “Our method overcomes the unfortunate property of fMRI to smear together the signals emanating from brain events that occur close together in time, like the reading of two successive words in a sentence,” Just explained.

"other 'mind reading' methods, such as UC Berkeley’s method for using fMRI and computational models to decode and reconstruct people’s imagined visual experiences. Plus whatever Neuralink discovers."

Also: "noninvasive functional near-infrared spectroscopy (fNIRS), Facebook’s Building8 research concept" - "a filter for creating quasi ballistic photons, avoiding diffusion and creating a narrow beam for precise targeting of brain areas, combined with a new method of detecting blood-oxygen levels."

Link shared by Dr. Robert Duncan

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