Magnetic Resonance Imaging, the Improbable Dream

After WWII, the advances in magnetic and radio technologies allowed a new spectroscopy to be developed, one that monitored stimulated radio emissions from the nuclei of some atoms. This was called Nuclear Magnetic Resonance Spectoscopy, or NMR. The signals were very weak and difficult to observe, but by 1960 it was known that the positions and strengths and appearance of the signals were governed by the chemical environments of the atoms whose nuclei were being monitored. Given the right conditions, and enough sample, here was a powerful new tool for uncovering molecular structure. The limitations were always in the amount of material available and its physical state, and the ability to maintain a very stable homogenous magnetic field over the sample, no simple task. In addition, the nuclei are very susceptible to overstimulation to the point where they can no longer respond.

Around 1960, the son of a Lebanese immigrant to New Jersey was already dreaming of using this type of spectroscopy to detect cancer in its early stages. He was motivated by his father's battle with cancer of the lung. The problems were many, not least of which was how to maintain a steady magnetic field over something as large as a human body.

The battle was slowly taken up by researchers in universities and industry, receiving an important boost with the availability of new computer systems that could both control the instruments and store vast amounts of data.

The presentation will go through important steps in the history of the development of the medical diagnostic tool we now know as MRI. Early on, the "nuclear" part of the name was dropped for obvious "public relations" reasons. The approach will be descriptive and not mathematical and is probably suited to older students.