Physics, Techniques and ProceduresEdge-packing
bright ring around the edge of the image which appears as characteristic non-uniformity in images. This
artefact (see
artefact in nuclear imaging) called edge packing, results from a somewhat greater light collection efficiency for events near the edge when compared to central regions of the detector crystal (
Anger camera). This occurs as a result of internal reflections of scintillation light from the sides of the detector back into the
photomultiplier tubes near the edge. Also for events occuring towards the centre of the crystal, there are always
PM tubes on either side of the event location, whereas at the edges of the crystal, there are
PM tubes only to one side. Thus events at the very edges are not distributed uniformly but are pulled toward the centre compounding the edge-packing
artefact.
DT