Gallium-67

Main isotopes of gallium

Iso­tope Decay abun­dance half-life mode energy (MeV) pro­duct 66Ga syn 9.5 h β+ 4.153 66Zn 67Ga syn 3.3 d ε 1.001 67Zn 68Ga syn 1.2 h β+ 1.899 68Zn 69Ga 60.11% is stable with 38 neutrons 70Ga syn 21 min β− 1.653 70Ge ε 0.655 70Zn 71Ga 39.89% is stable with 40 neutrons 72Ga syn 14.1 h β− 3.997 72Ge 73Ga syn 4.9 h β− 1.598 73Ge
Standard atomic weight (Ar)	69.723(1)

Natural gallium (₃₁Ga) consists of a mixture of two stable isotopes: gallium-69 and gallium-71. The most commercially important radioisotopes are gallium-67 and gallium-68.

Gallium-67 (half-life 3.3 days) is a gamma-emitting isotope (the gamma emitted immediately after electron-capture) used in standard nuclear medical imaging, in procedures usually referred to as gallium scans. It is usually used as the free ion, Ga³⁺. It is the longest-lived radioisotope of gallium.

The shorter-lived gallium-68 (half-life 68 minutes) is a positron-emitting isotope generated from germanium-68 in gallium-68 generators, for use in a small minority of diagnostic PET scans. For this use, it is usually attached as a tracer to a carrier molecule, which gives the resulting radiopharmaceutical a different tissue-uptake specificity from the ionic Ga-67 radioisotope normally used in standard gallium scans.

...
Wikipedia