Читать книгу Essentials of Nuclear Medicine Physics, Instrumentation, and Radiation Biology - Rachel A. Powsner - Страница 64

For generators where the half‐life of the parent is greater than 100 times that of the daughter nuclide, since we are interested in time‐scales on the order of the daughter half‐life, we just consider the parent nuclide to be stable.

Secular equilibrium, like transient equilibrium, is achieved rapidly following an elution that removes all of the available daughter nuclide. Thereafter the activity of the daughter nuclide is approximately equal to that of the parent. However, the decay curve of the parent appears to be flat since its half‐life is so much longer than that of the daughter nuclide. An example of secular equilibrium can be seen with the ⁸²Sr–⁸²Rb generator (see Figure 3.4).