Abstract: A device for teaching dental students and technicians how to adjust and position an X-ray cone relative to the upper or lower jaw of a patient to achieve a proper angle and maximum clarity for the particular purpose for which the X-ray picture is being taken which includes a simulated jaw or human head bearing teeth and a simulated X-ray cone together with miniaturized X-ray film images or projection slides of X-ray films, to be positioned and illuminated on demand, each picture appearing in response to a student selected particular position of the simulated cone relative to the jaw to show whether the cone is properly positioned. These X-ray pictures are made of a human skull. The simulated patient is a plastic reproduction of the original skull.

Abstract: A method and apparatus for demonstrating and recording an image of a surface of arbitrary shape and orientation within a body based on a set of tomographic records taken from a radiographic examination of the body. The tomographic records are overlaid on one another in superimposed relation, and then laterally shifted in concert with one another to bring into virtual focus a continuous succession of laminar images through the depth of the body. As the image of each successive body plane or lamina comes into focus, that part of the image that represents the intersection of the arbitrary surface with the imaged body plane or lamina is selected by masking out the remainder of the focused image. As the focusing progresses through the depth of the body, the entire arbitrary plane is demonstrated, and may be recorded by electronic or photographic means.