Bromine (35Br) has two stable isotopes, 79Br and 81Br, and 35 known radioisotopes, the most stable of which is 77Br, with a half-life of 57.036 hours.
Like the radioactive isotopes of iodine, radioisotopes of bromine, collectively radiobromine, can be used to label biomolecules for nuclear medicine; for example, the positron emitters 75Br and 76Br can be used for positron emission tomography.[1] [2] Radiobromine has the advantage that organobromides are more stable than analogous organoiodides, and that it is not uptaken by the thyroid like iodine.[3]
|-| 68Br[4] | style="text-align:right" | 35| style="text-align:right" | 33| 67.95836(28)#| ~35 ns| p?| 67Se| 3+#|||-| 69Br| style="text-align:right" | 35| style="text-align:right" | 34| 68.950338(45)| <19 ns[4] | p| 68Se| (5/2−)|||-| rowspan=2|70Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 35| rowspan=2|69.944792(16)| rowspan=2|78.8(3) ms| β+| 70Se| rowspan=2|0+| rowspan=2|| rowspan=2||-| β+, p?| 69As|-| rowspan=2 style="text-indent:1em" | 70mBr| rowspan=2 colspan="3" style="text-indent:2em" | 2292.3(8) keV| rowspan=2|2.16(5) s| β+| 70Se| rowspan=2|9+| rowspan=2|| rowspan=2||-| β+, p?| 69As|-| 71Br| style="text-align:right" | 35| style="text-align:right" | 36| 70.9393422(58)| 21.4(6) s| β+| 71Se| (5/2)−|||-| 72Br| style="text-align:right" | 35| style="text-align:right" | 37| 71.9365946(11)| 78.6(24) s| β+| 72Se| 1+|||-| rowspan=2 style="text-indent:1em" | 72mBr| rowspan=2 colspan="3" style="text-indent:2em" | 100.76(15) keV| rowspan=2|10.6(3) s| IT| 72Br| rowspan=2|(3-)| rowspan=2|| rowspan=2||-| β+?| 72Se|-| 73Br| style="text-align:right" | 35| style="text-align:right" | 38| 72.9316734(72)| 3.4(2) min| β+| 73Se| 1/2−|||-| 74Br| style="text-align:right" | 35| style="text-align:right" | 39| 73.9299103(63)| 25.4(3) min| β+| 74Se| (0−)|||-| style="text-indent:1em" | 74mBr| colspan="3" style="text-indent:2em" | 13.58(21) keV| 46(2) min| β+| 74Se| 4+|||-| rowspan=2|75Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 40| rowspan=2|74.9258106(46)| rowspan=2|96.7(13) min| β+ (76%)[3] | 75Se| rowspan=2|3/2−| rowspan=2|| rowspan=2||-| EC (24%)| 76Se|-| rowspan=2|76Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 41| rowspan=2|75.924542(10)| rowspan=2|16.2(2) h| β+ (57%)[3] | 76Se| rowspan=2|1−| rowspan=2|| rowspan=2||-| EC (43%)| 76Se|-| rowspan=2 style="text-indent:1em" | 76mBr| rowspan=2 colspan="3" style="text-indent:2em" | 102.58(3) keV| rowspan=2|1.31(2) s| IT (>99.4%)| 76Br| rowspan=2|(4)+| rowspan=2|| rowspan=2||-| β+ (<0.6%)| 76Se|-| rowspan=2|77Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 42| rowspan=2|76.9213792(30)| rowspan=2|57.04(12) h| EC (99.3%)[5] | 77Se| rowspan=2|3/2−| rowspan=2|| rowspan=2||-| β+ (0.7%)| 77Se|-| style="text-indent:1em" | 77mBr| colspan="3" style="text-indent:2em" | 105.86(8) keV| 4.28(10) min| IT| 77Br| 9/2+|||-| rowspan=2|78Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 43| rowspan=2|77.9211459(38)| rowspan=2|6.45(4) min| β+ (>99.99%)| 78Se| rowspan=2|1+| rowspan=2|| rowspan=2||-| β− (<0.01%)| 78Kr|-| style="text-indent:1em" | 78mBr| colspan="3" style="text-indent:2em" | 180.89(13) keV| 119.4(10) μs| IT| 78Br| (4+)|||-| 79Br| style="text-align:right" | 35| style="text-align:right" | 44| 78.9183376(11)| colspan=3 align=center|Stable| 3/2−| 0.5065(9)||-| style="text-indent:1em" | 79mBr| colspan="3" style="text-indent:2em" | 207.61(9) keV| 4.85(4) s| IT| 79Br| 9/2+|||-| rowspan=2|80Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 45| rowspan=2|79.9185298(11)| rowspan=2|17.68(2) min| β− (91.7%)| 80Kr| rowspan=2|1+| rowspan=2|| rowspan=2||-| β+ (8.3%)| 80Se|-| style="text-indent:1em" | 80mBr| colspan="3" style="text-indent:2em" | 85.843(4) keV| 4.4205(8) h| IT| 80Br| 5−|||-| 81Br| style="text-align:right" | 35| style="text-align:right" | 46| 80.9162882(10)| colspan=3 align=center|Stable| 3/2−| 0.4935(9)||-| style="text-indent:1em" | 81mBr| colspan="3" style="text-indent:2em" | 536.20(9) keV| 34.6(28) μs| IT| 81Br| 9/2+|||-| 82Br| style="text-align:right" | 35| style="text-align:right" | 47| 81.9168018(10)| 35.282(7) h| β−| 82Kr| 5−|||-| rowspan=2 style="text-indent:1em" | 82mBr| rowspan=2 colspan="3" style="text-indent:2em" | 45.9492(10) keV| rowspan=2|6.13(5) min| IT (97.6%)| 82Br| rowspan=2|2−| rowspan=2|| rowspan=2||-| β− (2.4%)| 82Kr|-| 83Br| style="text-align:right" | 35| style="text-align:right" | 48| 82.9151753(41)| 2.374(4) h| β−| 83Kr| 3/2−|||-| style="text-indent:1em" | 83mBr| colspan="3" style="text-indent:2em" | 3069.2(4) keV| 729(77) ns| IT| 83Br| (19/2−)|||-| 84Br| style="text-align:right" | 35| style="text-align:right" | 49| 83.916496(28)| 31.76(8) min| β−| 84Kr| 2−|||-| style="text-indent:1em" | 84m1| colspan="3" style="text-indent:2em" | 310(100) keV| 6.0(2) min| β−| 84Kr| (6)−|||-| style="text-indent:1em" | 84m2Br| colspan="3" style="text-indent:2em" | 408.2(4) keV| <140 ns| IT| 84Br| 1+|||-| 85Br| style="text-align:right" | 35| style="text-align:right" | 50| 84.9156458(33)| 2.90(6) min| β−| 85Kr| 3/2−|||-| 86Br| style="text-align:right" | 35| style="text-align:right" | 51| 85.9188054(33)| 55.1(4) s| β−| 86Kr| (1−)|||-| rowspan=2|87Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 52| rowspan=2|86.9206740(34)| rowspan=2|55.68(12) s| β− (97.40%)| 87Kr| rowspan=2|5/2−| rowspan=2|| rowspan=2||-| β−, n (2.60%)| 86Kr|-| rowspan=2|88Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 53| rowspan=2|87.9240833(34)| rowspan=2|16.34(8) s| β− (93.42%)| 88Kr| rowspan=2|(1−)| rowspan=2|| rowspan=2||-| β−, n (6.58%)| 87Kr|-| style="text-indent:1em" | 88mBr| colspan="3" style="text-indent:2em" | 270.17(11) keV| 5.51(4) μs| IT| 88Br| (4−)|||-| rowspan=2|89Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 54| rowspan=2|88.9267046(35)| rowspan=2|4.357(22) s| β− (86.2%)| 89Kr| rowspan=2|(3/2−, 5/2−)| rowspan=2|| rowspan=2||-| β−, n (13.8%)| 88Kr|-| rowspan=2|90Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 55| rowspan=2|89.9312928(36)| rowspan=2|1.910(10) s| β− (74.7%)| 90Kr| rowspan=2|| rowspan=2|| rowspan=2||-| β−, n (25.3%)| 89Kr|-| rowspan=2|91Br| rowspan=2 style="text-align:right" | 35| rowspan=2 style="text-align:right" | 56| rowspan=2|90.9343986(38)| rowspan=2|543(4) ms | β− (70.5%)| 91Kr| rowspan=2|5/2−#| rowspan=2|| rowspan=2||-| β−, n (29.5%)| 90Kr|-| rowspan=3|92Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 57| rowspan=3|91.9396316(72)| rowspan=3|314(16) ms| β− (66.9%)| 92Kr| rowspan=3|(2−)| rowspan=3|| rowspan=3||-| β−, n (33.1%)| 91Kr|-| β−, 2n?| 90Kr|-| style="text-indent:1em" | 92m1Br| colspan="3" style="text-indent:2em" | 662(1) keV| 88(8) ns| IT| 92Br| |||-| style="text-indent:1em" | 92m2Br| colspan="3" style="text-indent:2em" | 1138(1) keV| 85(10) ns| IT| 92Br| |||-| rowspan=3|93Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 58| rowspan=3|92.94322(46)| rowspan=3|152(8) ms| β−, n (64%)| 92Kr| rowspan=3|5/2−#| rowspan=3|| rowspan=3||-| β− (36%)| 93Kr|-| β−, 2n?| 91Kr|-| rowspan=3|94Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 59| rowspan=3|93.94885(22)#| rowspan=3|70(20) ms| β−, n (68%)| 93Kr| rowspan=3|2−#| rowspan=3|| rowspan=3||-| β− (32%)| 94Kr|-| β−, 2n?| 92Kr|-| style="text-indent:1em" | 94mBr| colspan="3" style="text-indent:2em" | 294.6(5) keV| 530(15) ns| IT| 94Br| |||-| rowspan=3|95Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 60| rowspan=3|94.95293(32)#| rowspan=3|80# ms [>300 ns]| β−?| 95Kr| rowspan=3|5/2−#| rowspan=3|| rowspan=3||-| β−, n?| 94Kr|-| β−, 2n?| 93Kr|-| style="text-indent:1em" | 95mBr| colspan="3" style="text-indent:2em" | 537.9(5) keV| 6.8(10) μs| IT| 95Br| |||-| rowspan=3|96Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 61| rowspan=3|95.95898(32)#| rowspan=3|20# ms [>300 ns]| β−?| 96Kr| rowspan=3|| rowspan=3|| rowspan=3||-| β−, n?| 95Kr|-| β−, 2n?| 94Kr|-| style="text-indent:1em" | 96mBr| colspan="3" style="text-indent:2em" | 311.5(5) keV| 3.0(9) μs| IT| 95Br| |||-| rowspan=3|97Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 62| rowspan=3|96.96350(43)#| rowspan=3|40# ms [>300 ns]| β−?| 97Kr| rowspan=3|5/2−#| rowspan=3|| rowspan=3||-| β−, n?| 96Kr|-| β−, 2n?| 95Kr|-| rowspan=3|98Br| rowspan=3 style="text-align:right" | 35| rowspan=3 style="text-align:right" | 63| rowspan=3|97.96989(43)#| rowspan=3|15# ms [>400 ns]| β−?| 98Kr| rowspan=3|| rowspan=3|| rowspan=3||-| β−, n?| 97Kr|-| β−, 2n?| 96Kr|-| 99Br[6] | style="text-align:right" | 35| style="text-align:right" | 64| | ||| | | |-| 100Br[6] | style="text-align:right" | 35| style="text-align:right" | 65| | ||| | | |-| 101Br[7] | style="text-align:right" | 35| style="text-align:right" | 66| | ||| ||
Bromine-75 has a half-life of 97 minutes. This isotope undergoes β+ decay rather than electron capture about 76% of the time,[3] so it was used for diagnosis and positron emission tomography (PET) in the 1980s.[1] However, its decay product, selenium-75, produces secondary radioactivity with a longer half-life of 120.4 days.[3] [1]
Bromine-76 has a half-life of 16.2 hours. While its decay is more energetic than 75Br and has lower yield of positrons (about 57% of decays),[3] bromine-76 has been preferred in PET applications since the 1980s because of its longer half-life and easier synthesis, and because its decay product, 76Se, is not radioactive.[2]
Bromine-77 is the most stable radioisotope of bromine, with a half-life of 57 hours. Although β+ decay is possible for this isotope, about 99.3% of decays are by electron capture.[5] Despite its complex emission spectrum, featuring strong gamma-ray emissions at 239, 297, 521, and 579 keV,[8] 77Br was used in SPECT imaging in the 1970s,[9] but except for longer-term tracing,[3] this is no longer considered practical due to the difficult collimator requirements and the proximity of the 521 keV line to the 511 keV annihilation radiation related to the β+ decay.[9] However, the auger electrons emitted during decay are well-suited for radiotherapy, and it can possibly be paired with the imaging-suited 76Br (produced as an impurity in common synthesis routes) for this application.[1] [9]