Scattering and its role in radiography simulations

The last decade has witnessed a proliferation of various radiography simulation codes. Most of these codes emphasize on a good geometrical representation of the test object. Simulated image formation is another point emphasized by these simulators. Most of the simulators use a variety of ways to generate primary beam photon energy spectrum. Apart from these common points, the simulation codes address photon object interactions with different sophistication levels. There has not been much discussion on what constitutes adequate level of physics used in these simulators. This paper provides a brief survey of these radiography efforts and discusses approaches adapted by various simulation efforts. Along with the survey of the simulation efforts, it provides an algorithm for computing scattered photon flux and shows impact of various parameters, assumptions and approximations.