Читать книгу Essentials of Nuclear Medicine Physics, Instrumentation, and Radiation Biology - Rachel A. Powsner - Страница 49

Because of the strong electrical force between a charged particle and the atoms of an absorber, charged particles can be stopped by matter with relative ease. Compared to photons, they transfer a greater amount of energy in a shorter distance and come to rest more rapidly. For this reason, they are referred to as nonpenetrating radiation (see depiction of alpha and beta particles in Figure 2.7). In contrast to a photon of 100 keV which has a HVL of 4 cm in soft tissue, an electron of this energy would penetrate less than 0.00014 cm in soft tissue [1].