Figure 1.

Schematic representation of the atomic in vivo nanogenerator ²²⁵Ac (τ_½ = 9.9 d, E_α = 5.8 MeV). ²²⁵Ac decays through four net α-disintegrations (five in total) and two net β^–-disintegrations (three in total) into stable ²⁰⁹Bi. The ²²⁵Ac decay chain possess two eligible γ-emissions for detection, 218 keV (I = 11.4%, ²²¹Fr) and 440 keV (I = 25.9%, ²¹³Bi). The most prominent daughter radionuclide is ²¹³Bi (τ_½ = 45.6 min, E_α = 5.9 MeV), which is also used for targeted alpha therapy (TAT) itself. The half-life (τ_½), known energies connected to recoil events (translational kinetic energy E_t), and the decay energies (E_α, E_β, E_γ) are indicated on the scheme. Data were derived from Nucleonica GmbH, Nuclide Datasheets, Nucleonica Nuclear Science Portal (www.nucleonica.com), Version 3.0.65, Karlsruhe (2017).