Table 1.

Distinct physical and biological properties of alpha, beta, and Auger electron emitting radioisotopes [17,30,31,33,34,35,36,37,38].

	Alpha Particle	Beta Particle	Auger Electron
Type of particles	4He nuclei	Energetic electrons	Low-energy electrons; electron capture and/or internal conversion
Energy range	4–9 MeV	50–2300 KeV	25–80 KeV
Emission range in tissues	28–100 µm	0.5–10 mm	<0.5 µm
LET (KeV/µm)	~50–230	~0.1–1.0	~4–26
Main mechanism of damage	At high doses: widespread DNA damage, leads to significant cellular damage and reduced repair capability to induce cell death or mutations with potential long-term effects. At low to moderate doses: DSBs, less reparable by cellular mechanisms.	At high doses: exponential relationship with tumor survival. The rate of DNA damage may exceed the cell’s repair capacity, leading to the accumulation of unrepaired or misrepaired DNA lesions. At low to moderate doses: linear relationship with tumor survival. Primarily involves SSBs and minor chemical modifications to DNA bases. Damage is more likely to be repaired by the cell’s repair mechanisms.	At high doses: multiple DSBs, lead to increased genetic instability and potential cell death. At low to moderate doses: clustered DNA damage, leads to complex lesions that overwhelm repair systems.
Tissue damage size	Small (a number of cells)	Higher volume solid tumor	Micro (a few cells)

LET: linear energy transfer, SSB: single-strand break, DSB: double-strand break, mm: millimeter.