"In panoramic image such as the orthopantomogram, structures within the focal trough (a panoramic arch similar to that of the teeth) will be sharp, well defined and overall lacking in distortion. Objects outside of this focal trough that are dense enough to attenuate x-rays will occasionally present twice as the x-ray tube rotates around the patient, this is known as a ghost image. The density will appear at the true location and secondly on the contralateral aspect of the image as a distorted 'ghost' image. The ghost image is distorted and larger than the actual object projected and often not at the same height 1."
Expected headings
"Real image vs ghost image"
"Practical points"