Isotopes of gallium

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.

Isotopes of gallium (₃₁Ga)

Main isotopes^[1] 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)
	69.723±0.001^[2] 69.723±0.001 (abridged)^[3]
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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 energy							Normal proportion	Range of variation
^56Ga	31	25	55.99491(28)#		p	^55Zn	3+#
^57Ga	31	26	56.98293(28)#		p	^56Zn	1/2−#
^58Ga	31	27	57.97425(23)#		p	^57Zn	2+#
^59Ga	31	28	58.96337(18)#		p	^58Zn	3/2−#
^60Ga	31	29	59.95706(12)#	70(10) ms	β^+	^60Zn	(2+)
^61Ga	31	30	60.94945(6)	168(3) ms	β^+	^61Zn	3/2−
^62Ga	31	31	61.944175(30)	116.18(4) ms	β^+	^62Zn	0+
^63Ga	31	32	62.9392942(14)	32.4(5) s	β^+	^63Zn	(3/2−)
^64Ga	31	33	63.9368387(22)	2.627(12) min	β^+	^64Zn	0(+#)
^64mGa	42.85(8) keV			21.9(7) μs			2+
^65Ga	31	34	64.9327348(9)	15.2(2) min	β^+	^65Zn	3/2−
^66Ga	31	35	65.931589(3)	9.49(7) h	β^+	^66Zn	0+
^67Ga^[n 8]	31	36	66.9282017(14)	3.2612(6) d	EC	^67Zn	3/2−
^68Ga^[n 9]	31	37	67.9279801(16)	67.71(9) min	β^+	^68Zn	1+
^69Ga	31	38	68.9255736(13)	Stable			3/2−	0.60108(9)
^70Ga	31	39	69.9260220(13)	21.14(3) min	β^− (99.59%)	^70Ge	1+
					EC (0.41%)	^70Zn
^71Ga	31	40	70.9247013(11)	Stable			3/2−	0.39892(9)
^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: view

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

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; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (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.

• Isotope masses from:
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
• Isotopic compositions and standard atomic masses from:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
• "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
• Half-life, spin, and isomer data selected from the following sources.
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
  • National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
  • Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.