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The rare stable isotope of helium (1.37 parts per million of ordinary helium); produced by the beta decay of tritium.
Farlex Partner Medical Dictionary © Farlex 2012
A stable isotope of helium whose nucleus contains two protons and a single neutron. The isotope is polarizable, making it suitable as a gaseous contrast agent for use in magnetic resonance imaging.
See also: helium
Medical Dictionary, © 2009 Farlex and Partners