Simplified diagram depicting how ghost images occur on an OPG.
Also note: Mesially impacted lower third molars (wisdom teeth)
Case courtesy of Dr Matthew Lukies, rID: 46588
Case Discussion
This is a simplified diagram replicating a common artefact seen on OPG. As the x-ray source and detector rotate around the patient dense objects (such as an earring) at the edge of the case, outside the focal trough - can cause 'ghost images'. These are seen at the contralateral aspect of the image and are distorted. If the reader is not careful, ghost images may replicate pathology - any dense material seen on an OPG should prompt the reader to carefully inspect the other side of the image for the original structure or ghost image.