There was an interesting result (at least to physicists and chemists) published this week which could have wide ranging effects on medicine and various other disciplines. Two groups of researchers have done some preliminary work on obtaining Nuclear Magnetic Resonance (NMR) without using magnets!

 That might seem rather dull and pedantic to many of you reading this, but allow me to digress for a moment and explain one reason why it is important...

One of the most powerful medical imaging methods currently is the MRI (magnetic resonance imaging). A patient can be placed in the machine, and with absolutely no ionizing radiation (and therefore no cancer risks) an image is formed of their internal organs. From this image doctors can determine and diagnose illnesses with no surgery or other discomforts to either patient or practitioner. 

In a traditional MRI, a very strong magnetic field lines up the spin axis of the hydrogen atoms in the patient's body. The process is too complicated to give in full detail, but the short version is that the atoms are rotated to be perpendicular to the magnetic field and then allowed to relax back to their original position. The rate at which they relax and the frequency of the resulting radio waves they generate correspond to the location and type of tissue in the body. And so by combining the signals from all the atoms, a complete image of the patient's internal organs can be generated.

The downside is that the magnetic fields must be very strong, which means very expensive and very large. It also means that patient's who have metal implanted in them cannot be imaged.

Several years ago a team in California developed a low field MRI machine that could produce similar results but with ordinary electromagnets. It also had the advantage of being able to detect certain types of breast cancer and prostate cancer which are normally invisible to the bigger MRI machines. Unfortunately it also requires expensive SQUID detectors and these need to be supercooled. 
 
And that is where the new discovery comes in...

These two teams have developed a detector that can measure J-coupling with no magnetic field. In simple terms, the protons in the atoms generate their own magnetic fields which only affect their nearest neighbours and so they cannot be detected normally. But with the new detector, the shift in the resonance frequency of the molecules due to this effect can be detected and in essence create a nuclear magnetic resonance effect without the magnetic field

Right now it is just academic. They need to infuse the substance with a slightly different form of hydrogen gas, which makes it untenable for patient studies, and they also haven't yet tested it with position encoding, which would also be required for medical use.

But it does suggest that in the future the technology could be improve to produce handheld MRI machines that a physician could basically wave over the patient and diagnose internal issues.

Suddenly the tricorder of Star Trek lore doesn't seem so far off...

More Information:
    LBL Press Release
    Nature Article