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Prologue

Council on Scientific Affairs

JAMA. 1987;258(22):3283-3285.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

IN THE 1920s and 1930s, several physicists measured the newly discovered magnetic properties of nuclei, especially those of the simplest element hydrogen. Among the physicists studying hydrogen were Rabi and colleagues,¹ whose work led to a Nobel prize in 1944. With Rabi's group's findings as a basis and with more refined experimental apparatus, Bloch² and Purcell³ subsequently independently measured the magnetic properties of the hydrogen nucleus (a single proton) to an accuracy of 1 ppm, for which they were awarded the Nobel prize in 1952.

Bloch and Purcell found that when certain atomic nuclei are placed in a magnetic field and exposed to radiofrequency (RF) energy, they emit a weak radio signal. By analyzing the amplitudes and frequencies of these signals, the chemical composition of the sample can be deduced. By the early 1950s, this approach (termed magnetic resonance [MR] spectroscopy) had been expanded to permit determination . . . [Full Text PDF of this Article]

Author Affiliations
From the Council on Scientific Affairs, American Medical Association, Chicago.

Footnotes
This report was presented to the House of Delegates of the American Medical Association 1986 Interim Meeting as an informational report of the Council on Scientific Affairs.

This report is not intended to be construed or to serve as a standard of medical care. Standards of medical care are determined on the basis of all of the facts and circumstances involved in an individual case and are subject to change as scientific knowledge and technology advance and patterns of practice evolve. This report reflects the views of the scientific literature as of December 1986.

Reprint requests to Council on Scientific Affairs, American Medical Association, 535 N Dearborn St, Chicago, IL 60610 (William R. Hendee, PhD).

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