Figure 2.

(A) Linear energy transfer (LET) versus distance in water traveled by typical α-particles emitted by radionuclides in development for α-particle radioimmunotherapy: ²²⁵Ac (5.829 MeV)/²¹³Bi (8.375 MeV), ²¹¹At (5.867 MeV), ²¹²Bi (6.08 MeV)/²¹²Po (8.78 MeV), ²²³Ra (5.716 MeV). The range of the α-particle and the position of the Bragg peaks are correlated with the initial energy of the α-particles. LET of α-particles in water was calculated using stopping-power and range tables (continuous slowing down approximation range) for electrons, protons and helium ions from the National Institute of Standards and Technology (NIST). (B) The deposition of heavy ion energy as a function of penetrating depth of (a) a pristine beam and (b) a modulated beam with widened stopping region (spread out Bragg peaks). This figure and legend were reproduced from [19].