Sub-second and Dynamic Computed Tomography Development at the Canadian Light Source

Dynamic CT is an emerging technique of uninterrupted acquisition of radiographic projections of a sample as it forms, deforms, or interacts to external conditions. However, a basic principle for correct tomographic reconstruction is that the sample remain unchanged during CT acquisition to avoid motion artefacts. To capture dynamic processes, either the sample stability is controlled above the limitations of the capture device, or tomographic data needs to be acquired faster. The former is used in dynamic CT joint studies through precisely controlled joint movements at clinical scanners. The Canadian Light Source (CLS) uses the latter approach as the high flux is several orders of magnitude greater than laboratory X-ray sources and well suited for sub-second acquisitions. The greater temporal resolution allows for tomographic reconstruction of an evolving sample, and the changing internal structures can be captured and visualized. Dedicated micro-CT systems are also capable of dynamic CT with scans on the order of 2 CTs/min. Computational and mechanical constraints limit dynamic CT studies to small samples for short periods of time. Research applications have been in material sciences and preliminary studies in small animals and medical implant design. In this abstract, dynamic CT was used to visualize the wet granulation process of pharmaceutical powders once in contact with water.