The effect and solution affected film image quality by the scattering radiation from the RT room

The structure of RT room is consist of concrete. Because of low cost and shielding efficiency, the concrete is used widely for building of RT room. But unfortunately, gamma radiation is scattered so much with the concrete and back scattering also very strong. The secondary radiation by back scattering will be big affected in making film image quality incase of heavy wall casting, it is needed long exposure time. The long exposure time means increasing of scattered radiation to the film. In the topic, the interaction of gamma radiation and materials by scattered radiation will discussed and also the attenuation of scattered radiation with concrete. It is the main object to find the method of minimizing the effects by the scattered radiation for each materials and its application.