**3. Auger electron cascades**

Auger-electrons, discovered by Lise Meitner in 1922 and by Pierre Auger in 1923, are formed when the vacancy created in an inner shell is filled with an electron from a higher energy level after electron capture. Auger-electrons have high LET Like α-particles (Cornelissen & Vallis, 2010). Auger-electron emitters, like 125I, deposit a concentrated amount of energy in even shorter distances than α-emitters. This means that these radionuclides need to be located in the vicinity of the tumor cell nucleus to be effective. For this reason, antibodies labeled with auger-emitting radionuclides need to target the entire tumor cell population for efficient therapy (Cornelissen & Vallis, 2010).
