Isotopes of gallium

Isotopes of gallium (31Ga)
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
66Ga synth 9.5 h β+ 66Zn
67Ga synth 3.3 d ε 67Zn
68Ga synth 1.2 h β+ 68Zn
69Ga 60.1% stable
70Ga synth 21 min β 70Ge
ε 70Zn
71Ga 39.9% stable
72Ga synth 14.1 h β 72Ge
73Ga synth 4.9 h β 73Ge
Standard atomic weight Ar°(Ga)

Natural gallium (31Ga) consists of a mixture of two stable isotopes: gallium-69 and gallium-71. Twenty-nine radioisotopes are known, all synthetic, with atomic masses ranging from 56 to 86; along with three nuclear isomers, 64mGa, 72mGa and 74mGa. Most of the isotopes with atomic mass numbers below 69 decay to isotopes of zinc, while most of the isotopes with masses above 71 decay to isotopes of germanium. Among them, 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 ray 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 in very small quantities from germanium-68 in gallium-68 generators or in much greater quantities by proton bombardment of 68Zn in low-energy medical cyclotrons, for use in a small minority of diagnostic PET scans. For this use, it is usually attached as a tracer to a carrier molecule (for example the somatostatin analogue DOTATOC), which gives the resulting radiopharmaceutical a different tissue-uptake specificity from the ionic 67Ga radioisotope normally used in standard gallium scans.

List of isotopes

Nuclide
Z N Isotopic mass (Da)
Half-life
Decay
mode

Daughter
isotope

Spin and
parity
Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
60Ga 31 29 59.95750(22)# 72.4(17) ms β+ (98.4%) 60Zn (2+)
β+, p (1.6%) 59Cu
β+, α? (<0.023%) 56Ni
61Ga 31 30 60.949399(41) 165.9(25) ms β+ 61Zn 3/2−
β+, p? (<0.25%) 60Cu
62Ga 31 31 61.94418964(68) 116.122(21) ms β+ 62Zn 0+
63Ga 31 32 62.9392942(14) 32.4(5) s β+ 63Zn 3/2−
64Ga 31 33 63.9368404(15) 2.627(12) min β+ 64Zn 0(+#)
64mGa 42.85(8) keV 21.9(7) μs IT 64Ga (2+)
65Ga 31 34 64.93273442(85) 15.133(28) min β+ 65Zn 3/2−
66Ga 31 35 65.9315898(12) 9.304(8) h β+ 66Zn 0+
67Ga 31 36 66.9282023(13) 3.2617(4) d EC 67Zn 3/2−
68Ga 31 37 67.9279802(15) 67.842(16) min β+ 68Zn 1+
69Ga 31 38 68.9255735(13) Stable 3/2− 0.60108(50)
70Ga 31 39 69.9260219(13) 21.14(5) min β (99.59%) 70Ge 1+
EC (0.41%) 70Zn
71Ga 31 40 70.92470255(87) Stable 3/2− 0.39892(50)
72Ga 31 41 71.9263663(11) 14.095(3) h β 72Ge 3−
72mGa 119.66(5) keV 39.68(13) ms IT 72Ga (0+)
73Ga 31 42 72.9251747(18) 4.86(3) h β 73Ge 3/2−
74Ga 31 43 73.926946(4) 8.12(12) min β 74Ge (3−)
74mGa 59.571(14) keV 9.5(10) s (0)
75Ga 31 44 74.9265002(26) 126(2) s β 75Ge (3/2)−
76Ga 31 45 75.9288276(21) 32.6(6) s β 76Ge (2+,3+)
77Ga 31 46 76.9291543(26) 13.2(2) s β 77Ge (3/2−)
78Ga 31 47 77.9316082(26) 5.09(5) s β 78Ge (3+)
79Ga 31 48 78.93289(11) 2.847(3) s β (99.911%) 79mGe (3/2−)#
β, n (.089%) 78Ge
80Ga 31 49 79.93652(13) 1.697(11) s β (99.11%) 80Ge (3)
β, n (.89%) 79Ge
81Ga 31 50 80.93775(21) 1.217(5) s β (88.11%) 81mGe (5/2−)
β, n (11.89%) 80Ge
82Ga 31 51 81.94299(32)# 0.599(2) s β (78.5%) 82Ge (1,2,3)
β, n (21.5%) 81Ge
83Ga 31 52 82.94698(32)# 308(1) ms β (60%) 83Ge 3/2−#
β, n (40%) 82Ge
84Ga 31 53 83.95265(43)# 0.085(10) s β, n (70%) 83Ge
β (30%) 84Ge
85Ga 31 54 84.95700(54)# 50# ms [>300 ns] 3/2−#
86Ga 31 55 85.96312(86)# 30# ms [>300 ns]
This table header & footer:
  1. ^ mGa – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  5. ^ Bold symbol as daughter – Daughter product is stable.
  6. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  7. ^ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  8. ^ Deexcitation gamma used in medical imaging
  9. ^ Medically useful radioisotope
  • Commercially available materials may have been subjected to an undisclosed or inadvertent isotopic fractionation. Substantial deviations from the given mass and composition can occur.[original research?]

Gallium-67

Gallium-67 (67
Ga
) has a half-life of 3.26 days and decays by electron capture and gamma emission (in de-excitation) to stable zinc-67. It is a radiopharmaceutical used in gallium scans (alternatively, the shorter-lived gallium-68 may be used). This gamma-emitting isotope is imaged by gamma camera.

Gallium-68

Gallium-68 (68
Ga
) is a positron emitter with a half-life of 68 minutes, decaying to stable zinc-68. It is a radiopharmaceutical, generated in situ from the electron capture of germanium-68 (half-life 271 days) owing to its short half-life. This positron-emitting isotope can be imaged efficiently by PET scan (see gallium scan); alternatively, the longer-lived gallium-67 may be used. Gallium-68 is only used as a positron emitting tag for a ligand which binds to certain tissues, such as DOTATOC, which is a somatostatin analogue useful for imaging neuroendocrine tumors. Gallium-68 DOTA scans are increasingly replacing octreotide scans (a type of indium-111 scan using octreotide as a somatostatin receptor ligand). The 68
Ga
is bound to a chemical such as DOTATOC and the positrons it emits are imaged by PET-CT scan. Such scans are useful in locating neuroendocrine tumors and pancreatic cancer. Thus, octreotide scanning for NET tumors is being increasingly replaced by gallium-68 DOTATOC scan.


This page was last updated at 2024-04-17 14:33 UTC. Update now. View original page.

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