The next significant discoveries came in 1937 from Columbia University Professor Isidor I Rabi, and in 1946, from Felix Bloch at Stanford, and Edward Mills Purcell at the Massachusetts Institute of Technology, who discovered and demonstrated the quantum phenomenon known as nuclear magnetic resonance (NMR).
In simple words, NMR allowed scientist to see the structure of a molecule in detail. All three received the Nobel Prize for their efforts.
Now, the work by Rabi, Bloch and Purcell laid the foundations for the second generation of scientists in the 1970s, who discovered how to create images from the NMR signal.
Up until the 1970s, MRI technology was only being used for chemical and physical analysis. Enter Raymond Damadian, a doctor, who wondered if the same methods could be used on living organisms to detect disease.
In 1971, he concluded that since cancerous tissue contained more water than healthy tissue, it could be detected by scanners that bathed a part of the human body in radio waves and measured the emissions from the local hydrogen atoms. Damadian then began building a full body scanner called the Indomitable.