A stochastic approach to tracer kinetics.

The single compartment well-mixed model ( SCWMM ) which has been used in almost all dynamic studies in nuclear medicine is, in fact , strictly accurate only in the case of a steady state obtained by means of constant administration of long-lived isotopes. That is the reason why SCWMM is not a good predictor of the behaviour of short-lived isotopes and why the distribution and transport of short- and long-lived isotopes in various situations has not yet been discussed in general terms. The aim of this paper is to do that by means of a more general stochastic approach. This more general approach takes into account the distribution and transport of tracer in the system, not requiring a hypothesis of good mixing and providing a possibility of making corrections due to decay in the case of short-lived isotopes studies.