Selection of Time-after-injection in Bone Scanning using Compartmental Observers

An approach to assist the determination of the best time-after-injection for taking an scintigram in bone scanning is proposed. More precisely, a technique is discussed to estimate the evolution of the portions, in different compartments of the body, of the injected dose using a model of the radionuclide distribution dynamics, the available measurements and information on variations of the parameters. At each time, the possible range of variation of these unmeasured states is evaluated, and from this the expected evolution of the contrast of the image is obtained. This makes it possible to predict the best time for taking the image. To show the applicability, a practical example is provided.