Nuclear tomography methods in industry

This paper reviews the foundation of gamma-ray transmission tomography methods in industry. There are two categories of industrial tomography systems; those using a single source and automatic scanning, and those using multiple sources and no mechanical scanning. The main purpose of the latter is to reveal the dynamics of industrial processes. Compared to medical tomography temporal resolution is more important for these systems than spatial resolution. Such systems have also been realised using electronic scanning of multiple X-ray sources. Examples on different systems are given. Future developments include dual energy and multiple modality configurations enabling component fraction measurements on multiphase systems. Tomographic methods are also being implemented in permanently installed gauges with a limited number of projections, a priori information and parametric description of the process rather than reconstructed images.