Positron Emission Particle Tracking is a technique for measuring the trajectory of a single tracer particle moving within a system of flow, or attached to a rigid body in motion. The tracer is pre-labelled with a proton rich radionuclide which decays via positron emission. The nearly co-linear 511 keV gamma rays formed by positron annihilation are detected in coincidence by two opposing detectors within a PET scanner, thereby defining their line of response (LOR). If a number of such LORs are measured and recorded chronologically then they may be used to triangulate the position of the tracer. In principle only two such LORs are necessary, but the recording of non-useful LORs resulting from the detection of gamma rays after undergoing Compton scattering between creation and detection, and the coincident detection of two gamma rays which were not associated with the same annihilation event, mean that a larger number of measured LORs are required. However, since many millions of coincidence events can be processed by a PET camera each second, the possibility of tracking the position of a moving particle may be realised. PEPT was developed in the early 1990s by a group at the University of Birmingham, UK. After the Positron Imaging Centre at the University of Birmingham, PEPT Cape Town became the second operational PEPT facility in the world during 2009. Over the last decade, a wide range of PEPT applications have been explored, in particular, powder mixing, particle and fluid behaviour in granular beds, rotating drums, stirred tanks and flotation cells.
Department of Physics
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University of Cape Town
+27 (0) 21 650 3339 / 3326 Andy Buffler