1988 Volume 28 Issue 4 Pages 472-480
The alterations of the projected images on the rotational panoramic radiography were examined in six directions of a X-ray beam. A test object was placed at various positions in and around the image layer and the vertical and horizontal length of the projected images were measured.
The vertical length of the images decreased as the object was placed toward a film and no difference was found among six directions. The horizontal length increased exponentially as the position of the object was changed toward the X-ray tube. On the other hand, toward the film, it decreased slightly near the center of the image layer and increased slightly beyond it. This alteration was the most marked in the mid-sagittal direction and became less as the direction of the X-ray beam moved away from the mid-sagittal direction.
It was thought that the direction of the X-ray beam must be taken into consideration to recognize the alteration of the horizontal length of projected images.
