Isotopes of gallium

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Isotopes of gallium  (31Ga)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
66Ga synth 9.5 h β+ 66Zn
67Gasynth3.3 d ε 67Zn
68Gasynth1.2 hβ+ 68Zn
69Ga60.1% stable
70Gasynth21 min β− 70Ge
ε 70Zn
71Ga39.9%stable
72Gasynth14.1 hβ− 72Ge
73Gasynth4.9 hβ− 73Ge
Standard atomic weight Ar°(Ga)
  • 69.723±0.001
  • 69.723±0.001 (abridged) [2] [3]

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.

Contents

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, [4] [5] 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
[n 1] 		Z N Isotopic mass (Da)
[n 2] [n 3] 		Half-life
Decay
mode
[n 4] 		Daughter
isotope
[n 5] 		Spin and
parity
[n 6] [n 7] 		Natural abundance (mole fraction)
Excitation energyNormal proportionRange of variation
56Ga312555.99491(28)# p 55Zn3+#
57Ga312656.98293(28)#p56Zn1/2−#
58Ga312757.97425(23)#p57Zn2+#
59Ga312858.96337(18)#p58Zn3/2−#
60Ga312959.95706(12)#70(10) ms β+ 60Zn(2+)
61Ga313060.94945(6)168(3) msβ+61Zn3/2−
62Ga313161.944175(30)116.18(4) msβ+62Zn0+
63Ga313262.9392942(14)32.4(5) sβ+63Zn(3/2−)
64Ga313363.9368387(22)2.627(12) minβ+64Zn0(+#)
64mGa42.85(8) keV21.9(7) μs2+
65Ga313464.9327348(9)15.2(2) minβ+65Zn3/2−
66Ga313565.931589(3)9.49(7) hβ+66Zn0+
67Ga [n 8] 313666.9282017(14)3.2612(6) d EC 67Zn3/2−
68Ga [n 9] 313767.9279801(16)67.71(9) minβ+68Zn1+
69Ga313868.9255736(13)Stable3/2−0.60108(9)
70Ga313969.9260220(13)21.14(3) minβ− (99.59%)70Ge1+
EC (0.41%)70Zn
71Ga314070.9247013(11)Stable3/2−0.39892(9)
72Ga314171.9263663(11)14.095(3) hβ−72Ge3−
72mGa119.66(5) keV39.68(13) ms IT 72Ga(0+)
73Ga314272.9251747(18)4.86(3) hβ−73Ge3/2−
74Ga314373.926946(4)8.12(12) minβ−74Ge(3−)
74mGa59.571(14) keV9.5(10) s(0)
75Ga314474.9265002(26)126(2) sβ−75Ge(3/2)−
76Ga314575.9288276(21)32.6(6) sβ−76Ge(2+,3+)
77Ga314676.9291543(26)13.2(2) sβ−77Ge(3/2−)
78Ga314777.9316082(26)5.09(5) sβ−78Ge(3+)
79Ga314878.93289(11)2.847(3) sβ− (99.911%)79mGe(3/2−)#
β−, n (.089%)78Ge
80Ga314979.93652(13)1.697(11) sβ− (99.11%)80Ge(3)
β−, n (.89%)79Ge
81Ga315080.93775(21)1.217(5) sβ− (88.11%)81mGe(5/2−)
β−, n (11.89%)80Ge
82Ga315181.94299(32)#0.599(2) sβ− (78.5%)82Ge(1,2,3)
β−, n (21.5%)81Ge
83Ga315282.94698(32)#308(1) msβ− (60%)83Ge3/2−#
β−, n (40%)82Ge
84Ga315383.95265(43)#0.085(10) sβ−, n (70%)83Ge
β− (30%)84Ge
85Ga315484.95700(54)#50# ms [>300 ns]3/2−#
86Ga315585.96312(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

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. [6] Thus, octreotide scanning for NET tumors is being increasingly replaced by gallium-68 DOTATOC scan. [7]

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References

  1. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ↑ "Standard Atomic Weights: Gallium". CIAAW. 1987.
  3. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  4. ↑ Kumlin, J; Dam, J; Langkjaer, N; Chua, C.J.; Borjian, S.; Kassaian, A; Hook, B; Zeisler, S; Schaffer, P; Helge, Thisgaard (October 2019). "Multi-Curie Production of Ga-68 on a Biomedical Cyclotron". Conference: EANM'19. Retrieved 13 December 2019.
  5. ↑ Thisgaard, Helge; Kumlin, Joel; Langkjær, Niels; Chua, Jansen; Hook, Brian; Jensen, Mikael; Kassaian, Amir; Zeisler, Stefan; Borjian, Sogol; Cross, Michael; Schaffer, Paul (2021-01-07). "Multi-curie production of gallium-68 on a biomedical cyclotron and automated radiolabelling of PSMA-11 and DOTATATE". EJNMMI Radiopharmacy and Chemistry. 6 (1): 1. doi: 10.1186/s41181-020-00114-9 . ISSN   2365-421X. PMC   7790954 . PMID   33411034.
  6. ↑ Hofman, M.S.; Kong, G.; Neels, O.C.; Eu, P.; Hong, E.; Hicks, R.J. (2012). "High management impact of Ga-68 DOTATATE (GaTate) PET/CT for imaging neuroendocrine and other somatostatin expressing tumours". Journal of Medical Imaging and Radiation Oncology. 56 (1): 40–47. doi: 10.1111/j.1754-9485.2011.02327.x . PMID   22339744. S2CID   21843609.
  7. ↑ Scott, A, et al. (2018). "Management of Small Bowel Neuroendocrine Tumors". Journal of Oncology Practice. 14 (8): 471–482. doi:10.1200/JOP.18.00135. PMC   6091496 . PMID   30096273.
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