Читать книгу Essentials of Nuclear Medicine Physics, Instrumentation, and Radiation Biology - Rachel A. Powsner - Страница 43

In the practice of nuclear medicine, where gamma rays with energies between 50 keV and 550 keV are used, Compton scattering is the dominant type of interaction in materials with lower atomic numbers, such as human tissue (Z = 7.5). The photoelectric effect is the dominant type of interaction in materials with higher atomic numbers, such as lead (Z = 82). A third type of interaction of photons with matter, pair production, only occurs with very high photon energies (greater than 1020 keV) and is therefore not important in clinical nuclear medicine. Figure 2.1 depicts the predominant type of interaction for various combinations of incident photons and absorber atomic numbers.