TABLE 1

Physical Properties of Radionuclides Studied (22)

Property	^99mTc	¹²³I	¹²⁵I	¹³¹I	²¹¹At
Decay mode	IT	EC	EC	β⁻	α, EC
Half-life	6.0 h	13 h	60 d	8.0 d	7.2 h
Radiation yield (%)
Photon energy
0–40 keV	7.9	95	160	5.5	18
40–100 keV	—	—	—	—	38
100–300 keV	87	83	—	6.1	—
>300 keV	—	—	—	88	—
Electron energy
0–10 keV	220	280	600	8.0	9.4
10–20 keV	2.1	—	—	3.4	17
20–40 keV	—	12	33	7.4	—
40–100 keV	—	—	—	24	1.3
100–300 keV	11	16	—	48	—
300–600 keV	—	—	—	21	—
α-Particle energy
5,000–6,000 keV	—	—	—	—	42
6,000–7,000 keV	—	—	—	—	0.63
7,000–8,000 keV	—	—	—	—	58

EC = electron capture; IT = isomeric transition.
α-Particles, β-particles, and atomic electrons are included. Photons with abundance ≥ 5% and electrons with abundance ≥ 1% are included.