Unstable copper isotopes with atomic masses below 63 tend to undergo β+ decay, while isotopes with atomic masses above 65 tend to undergo β− decay.
Both stable isotopes of copper (63Cu and 65Cu) have nuclear spin of 3/2−, and thus produce nuclear magnetic resonance spectra, although the spectral lines are broad due to quadrupolar broadening.
63Cu is the more sensitive nucleus while 65Cu yields very slightly narrower signals.
[8] Copper offers a relatively large number of radioisotopes that are potentially useful for nuclear medicine.
For example, 64Cu has a longer half-life than most positron-emitters (12.7 hours) and is thus ideal for diagnostic PET imaging of biological molecules.