the selective absorption of electromagnetic radiation by an atomic nucleus in the presence of a strong, static, magnetic field: used in research and in medicine to monitor tissue metabolism and to distinguish between normal and abnormal cells.
a technique for determining the magnetic moments of nuclei by subjecting a substance to high-frequency radiation and a large magnetic field. The technique is used as a method of determining structure NMR See also electron spin resonance
nuclear magnetic resonance n.
Abbr. NMR The absorption of electromagnetic radiation of a specific frequency by an atomic nucleus that is placed in a strong magnetic field, used especially in spectroscopic studies of molecular structure and in medicine to measure rates of metabolism.
nuclear magnetic resonance
The absorption of electromagnetic energy (typically radio waves) by the nuclei of atoms placed in a strong magnetic field. The nuclei of different atoms absorb unique frequencies of radiation depending on their environment, thus by observing which frequencies are absorbed by a sample placed in a strong magnetic field (and later emitted again, when the magnetic field is removed), it is possible to learn much about the sample’s makeup and structure. Nuclear magnetic resonance has no known side effects on the human body, and is therefore used to analyze soft body tissues in magnetic resonance imaging (MRI).
- Nuclear magnetic resonance scanner
noun 1. a machine for the medical technique in which changes in the constituent atoms of the body under the influence of a powerful electromagnet are used to generate computed images of the internal organs
noun, Physics. 1. a unit of magnetic moment, used to measure proton spin and approximately equal to 1/1836 . nuclear magneton See under magneton.
noun 1. diagnostic and therapeutic medical techniques using radionuclides or radioisotopes. noun 1. the branch of medicine concerned with the use of radionuclides in the diagnosis and treatment of disease nuclear medicine n. The branch of medicine that deals with the use of radionuclides in the diagnosis and treatment of disease.
noun, Biology. 1. the double membrane surrounding the nucleus within a cell. nuclear membrane n. The double-layered membrane enclosing the nucleus of a cell. Also called nuclear envelope. nuclear membrane See nuclear envelope.