Ghost images originate from objects located between which of the following?

• A. Between the center of rotation and the receptor
• B. In front of the focal trough
• C. Between the x-ray source and the center of rotation
• D. At or near the center of rotation

Answer: (C)

Dense objects create ghost images in panoramic radiography because of the way the system projects anatomy along a curved path around a fixed center of rotation. When a dense object sits between the X-ray source and that center of rotation, it blocks part of the beam in a way that its image is projected onto the opposite side of the film. The geometry causes a secondary, magnified, and blurred projection of the object on the far side of the image, known as a ghost image. Objects like jewelry or glasses can cause this if they are located between the X-ray source and the center of rotation. If the object were between the center of rotation and the receptor, or at the center itself, it would not produce the same contralateral ghost projection.