¹³⁵Tb — Unstable · t½ ≈ 19 s · Decay: β⁺ → ¹³⁵Gd · Type: synthetic · Uses: research.
¹³⁶Tb — Unstable · t½ ≈ 1.1 min · Decay: β⁺ → ¹³⁶Gd · Type: synthetic · Uses: research.
¹³⁷Tb — Unstable · t½ ≈ 2.4 min · Decay: β⁺ → ¹³⁷Gd · Type: synthetic · Uses: research.
¹³⁸Tb — Unstable · t½ ≈ 4.0 min · Decay: β⁺ → ¹³⁸Gd · Type: synthetic · Uses: research.
¹³⁹Tb — Unstable · t½ ≈ 4.7 min · Decay: β⁺ → ¹³⁹Gd · Type: synthetic · Uses: research.
¹⁴⁰Tb — Unstable · t½ ≈ 15.0 s · Decay: β⁺ → ¹⁴⁰Gd · Type: synthetic · Uses: research.
¹⁴¹Tb — Unstable · t½ ≈ 3.5 min · Decay: β⁺ → ¹⁴¹Gd · Type: synthetic · Uses: research.
¹⁴²Tb — Unstable · t½ ≈ 17.0 min · Decay: β⁺ → ¹⁴²Gd · Type: synthetic · Uses: research.
¹⁴³Tb — Unstable · t½ ≈ 2.4 h · Decay: β⁺ → ¹⁴³Gd · Type: synthetic · Uses: research.
¹⁴⁴Tb — Unstable · t½ ≈ 4.25 h · Decay: β⁺ → ¹⁴⁴Gd · Type: synthetic · Uses: research.
¹⁴⁵Tb — Unstable · t½ ≈ 5.3 h · Decay: β⁺ → ¹⁴⁵Gd · Type: synthetic · Uses: research.
¹⁴⁶Tb — Unstable · t½ ≈ 4.9 h · Decay: β⁻ → ¹⁴⁶Dy · Type: activation product · Uses: tracer.
¹⁴⁷Tb — Unstable · t½ ≈ 1.6 h · Decay: β⁻ → ¹⁴⁷Dy · Type: synthetic · Uses: research.
¹⁴⁸Tb — Unstable · t½ ≈ 60.0 min · Decay: β⁻ → ¹⁴⁸Dy · Type: synthetic · Uses: research.
¹⁴⁹Tb — Unstable · t½ ≈ 4.1 h · Decay: β⁻ → ¹⁴⁹Dy · Type: synthetic · Uses: research.
¹⁵⁰Tb — Unstable · t½ ≈ 3.5 h · Decay: β⁻ → ¹⁵⁰Dy · Type: synthetic · Uses: research.
¹⁵¹Tb — Unstable · t½ ≈ 17.6 h · Decay: β⁻ → ¹⁵¹Dy · Type: synthetic · Uses: research.
¹⁵²Tb — Unstable · t½ ≈ 17.5 h · Decay: β⁻ → ¹⁵²Dy · Type: synthetic · Uses: research.
¹⁵³Tb — Unstable · t½ ≈ 2.3 d · Decay: β⁻ → ¹⁵³Dy · Type: synthetic · Uses: tracer.
¹⁵⁴Tb — Unstable · t½ ≈ 21.5 h · Decay: β⁻ → ¹⁵⁴Dy · Type: synthetic · Uses: research.
¹⁵⁵Tb — Unstable · t½ ≈ 5.3 d · Decay: β⁻ → ¹⁵⁵Dy · Type: synthetic · Uses: tracer.
¹⁵⁶Tb — Unstable · t½ ≈ 5.35 d · Decay: β⁻ → ¹⁵⁶Dy · Type: tracer · Uses: medical imaging, research.
¹⁵⁷Tb — Unstable · t½ ≈ 71 h · Decay: β⁻ → ¹⁵⁷Dy · Type: tracer · Uses: medical diagnostics.
¹⁵⁸Tb — Unstable · t½ ≈ 180 y · Decay: β⁻ → ¹⁵⁸Dy · Type: long-lived radionuclide · Uses: tracer, nuclear physics.
¹⁵⁹Tb — Unstable · t½ ≈ 5.0 s · Decay: β⁻ → ¹⁵⁹Dy · Type: synthetic · Uses: research.
¹⁶⁰Tb — Unstable · t½ ≈ 72.3 d · Decay: β⁻ → ¹⁶⁰Dy · Type: activation product · Uses: tracer.
¹⁶¹Tb — Unstable · t½ ≈ 6.9 d · Decay: β⁻ → ¹⁶¹Dy · Type: medical isotope · Uses: targeted radiotherapy (clinical trials).
¹⁶²Tb — Unstable · t½ ≈ 36.0 h · Decay: β⁻ → ¹⁶²Dy · Type: synthetic · Uses: research.
¹⁶³Tb — Unstable · t½ ≈ 19.0 min · Decay: β⁻ → ¹⁶³Dy · Type: synthetic · Uses: research.
¹⁶⁴Tb — Unstable · t½ ≈ 3.0 h · Decay: β⁻ → ¹⁶⁴Dy · Type: synthetic · Uses: research.
¹⁶⁵Tb — Unstable · t½ ≈ 6.3 min · Decay: β⁻ → ¹⁶⁵Dy · Type: synthetic · Uses: research.
¹⁶⁶Tb — Unstable · t½ ≈ 26.7 h · Decay: β⁻ → ¹⁶⁶Dy · Type: medical isotope · Uses: therapeutic radiotracer (clinical research).
¹⁶⁷Tb — Unstable · t½ ≈ 5.5 h · Decay: β⁻ → ¹⁶⁷Dy · Type: synthetic · Uses: research.
¹⁶⁸Tb — Unstable · t½ ≈ 3.0 min · Decay: β⁻ → ¹⁶⁸Dy · Type: synthetic · Uses: research.
¹⁶⁹Tb — Unstable · t½ ≈ 9.0 min · Decay: β⁻ → ¹⁶⁹Dy · Type: synthetic · Uses: research.
¹⁷⁰Tb — Unstable · t½ ≈ 9.1 d · Decay: β⁻ → ¹⁷⁰Dy · Type: activation product · Uses: tracer.
¹⁷¹Tb — Stable · — · Type: stable (primordial, only stable isotope) · Uses: isotope tracer, permanent magnets, alloys.
Terbium — isotope count: 37 total · Stable: 1 (¹⁷¹Tb) · Unstable: 36.
(Data: IAEA LiveChart, NUBASE2020, ENSDF; notable applications: ¹⁶¹Tb & ¹⁶⁶Tb in nuclear medicine, ¹⁵²Tb/¹⁵⁸Tb as tracers, stable ¹⁷¹Tb in magnets and alloys.)