MRI detects a single atom

In my novel ‘Thirty’ everyone undergoes an annual health scan that detects and fixes any disease or genetic changes. This keeps everyone young and healthy forever. We’re not quite there yet in the real world, but scientists in Switzerland have managed to use magnetic resonance imaging (MRI) to detect a single atom.

MRI can detect single atom
MRI image of the human brain

MRI machines use electromagnetic and radio waves to produce images of our bodies. The electromagnetic coils produce strong magnetic fields and hydrogen atoms in our bodies respond to those fields. Our bodies are of 70% water and that water contains billions of hydrogen atoms. All of these atoms are spinning, but along different axes. When we are exposed to the strong magnetic field in an MRI machine, all the hydrogen start to spin on the same axis. Then a radio wave is turned on and off in the machine. This causes the magnetic pull on the atoms to be deflected and then go back to normal. The movement back to normal creates a second radio wave that is captured by receiver coils and turned into the grayscale images we associate with MRI.

These images show different tissues in varying shades of grey and can detect something as small as 1/10th of a millimetre. That allows fairly early detection of diseases like cancer. But that scale is much bigger than a hydrogen atom which is 0.1 nanometres or 10 billionths of a metre across.

If we could detect down to the atomic level, we could see right into our cells. We could actually see what is different between a young healthy cell and an old or diseased cell. We could track in real time what is happening to our cells as we age. And once we had that knowledge, the next step would be to reverse the ageing changes and keep cells young. That is exactly what scientists do in my novel.

To detect the single atom, the Swiss scientists used a different approach to conventional MRI. They used a flawed diamond chip and fluorescent microscope to detect the magnetic field of surrounding atoms. Diamonds are made up of a regular lattice of carbon atoms. The diamond sensor had two carbon atoms missing – one replaced with a nitrogen atom. This defect made the diamond fluorescent and magnetic. So it could now detect another magnetic atom nearby. But only within a range of 4 nanometres. Not enough to measure human cells which are over 2000 times bigger than that. It will be interesting to see whether this technology can be scaled up enough to image to human body.

The Scientific Paper:

 Loretz et al. Single-proton spin detection by diamond magnetometry. Science. 2014

Berger. Magnetic Resonance Imaging. BMJ 2002

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