The Effects of Radiation on Biological Systems

Abstract

A source of radiation (radioactive material) is emission of particles of α, β, and γ, and the level of radioactivity is measured in terms of Bq, the number of decaying nuclei per second, which can usually be assumed to be equal to the number of radiation particles emitted. However, this is not exactly correct in certain cases. This value Bq represents, in a way, the number of radioactive nuclei present, as it is related to Bq = kN, where k is numerically a constant, indicating the probability per second of decay for a nucleus, and N is the number of that nuclei. The Bq value we will be dealing with will be something like the order of one to 1020. If the radionuclide is Cs-137, k = 7.3 × 10−10 (see Table 2.2) and 1010 Bq represents 1.4 × 1019 Cs-137 nuclei, which is 2.3 × 10−5 mol = 3.2 mg. 1020 Bq represents 3.2 × 107 g = 32 t (of Cs atoms). Similar calculations have been shown for other nuclides earlier (refer to Table 2.2).