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Nuclear Magnetic Resonance

Medical Applications

The largest area of application of NMR is in medical diagnosis. In this area, the technology is usually referred to as magnetic resonance imaging (MRI). The principle of MRI is identical to that of the use of NMR in chemical analysis. Essentially, the different materials in the body resonate at different frequencies depending on their chemical compositions. Position information is obtained by using an external magnetic field which varies with position, so that resonance at a particular frequency with a given substance, such as fatty tissue, will occur only at a particular position or set of positions within the body. The resonant response is then analyzed and displayed using a computer.


Resources

Books

Grant, David, and Robin Harris. Encyclopedia of Nuclear Magnetic Resonance. New York: Wiley, 2003.

Hewitt, Paul. Conceptual Physics. New York: Prentice Hall, 2001.

Slichter, Charles P. Principles of Magnetic Resonance. New York: Harper Row, 1963.

Periodicals

Naeye, Robert. "Magnetic Field Goal." Discover (June 1995): 128.

Pake, George E. "Nuclear Magnetic Resonance in Bulk Matter." Physics Today (October 1993): 46.

Ramsey, Norman F. "Early Magnetic Resonance Experiments: Roots and Offshoots." Physics Today (October 1993): 40.

KEY TERMS

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Angular momentum

—Rotational momentum; resistance to change in rotation rate.

Atomic nucleus

—The small, dense, central portion of an atom.

Gyration

—Motion similar to that of a gyroscope; the precession of rotation axis.

Induction

—The process in which a changing magnetic field causes electric current.

Magnetic moment

—The strength of a magnetized object.

Oscillation

—A smooth vibrational motion or change.

Precession

—A systematic change in the direction of a rotation axis.

Resonance

—The enhancement of the response of a system to a force, when that force is applied at a particular frequency known as the resonant frequency.

Additional topics

Science EncyclopediaScience & Philosophy: Nicotinamide adenine dinucleotide phosphate (NADP) to Ockham's razorNuclear Magnetic Resonance - History, Physcial principles, Nuclear spin magnetic moment, Magnetic torque on a nucleus, Nuclear orientation energy