. 2019 Jul 26;9:10884. doi: 10.1038/s41598-019-47463-3

Table 1.

Physical properties of four terbium isotopes and their applications in nuclear medicine^1,2.

Isotope	T_1/2	Decay mode (branching ratio)	Energy of particle radiation	Energy of main γ and X-ray emissions (keV)	Application
Isotope	T_1/2	Decay mode (branching ratio)	Energy of particle radiation	Energy of main γ and X-ray emissions (keV)	α therapy	PET	SPECT	β/auger therapy
¹⁴⁹Tb	4.12 h	α (16.7%) β⁺ (7.1%)	E_α = 3.967 MeV E_β+mean = 730 keV	352 (29%) 165 (26%)	x	x
¹⁵²Tb	17.5 h	β⁺ (17%)	E_β+mean = 1.080 MeV	344 (64%)		x
¹⁵⁵Tb	5.32 d	EC (100%)	—	43 (86%) 49 (20%) 87 (32%) 105 (25%)			x
¹⁶¹Tb	6.89 d	β⁻ (100%)	E_β-mean = 154 keV	26 (23%) 45–46 (18%) 49 (17%) 75 (10%)			x	x

EC – electron capture; PET – positron emission tomography; SPECT – single photon emission computed tomography.