Relevance of accurate Monte Carlo modeling in nuclear medical imaging

Monte Carlo techniques have become popular in different areas of medical ph ysics with advantage of powerful computing systems. In particular, they hav e been extensively applied to simulate processes involving random behavior and to quantify physical parameters that are difficult or even impossible t o calculate by experimental measurements. Recent nuclear medical imaging in novations such as single-photon emission computed tomography (SPECT), posit ron emission tomography (PET), and multiple emission tomography (MET) are i deal for Monte Carlo modeling techniques because of the stochastic nature o f radiation emission, transport and detection processes. Factors which have contributed to the wider use include improved models of radiation transpor t processes, the practicality of application with the development of accele ration schemes and the improved speed of computers. In this paper we presen t a derivation and methodological basis for this approach and critically re view their areas of application in nuclear imaging. An overview of existing simulation programs is provided and illustrated with examples of some usef ul features of such sophisticated tools in connection with common computing facilities and more powerful multiple-processor parallel pro(c)essing syst ems. Current and future trends in the field are also discussed. (C) 1999 Am erican Association of Physicists in Medicine. [S0094-2405(99)01904-5].