Panoramic Radiography Flashcards
What Principle is Used?
Tomography
- tube and image receptor move
the acquisition of multiple cross-sectional images of an object from different angles and the reconstruction of these images to form a three-dimensional representation.
Define Focal Trough
curved, in focus piece of anatomy
outside structures are blurred
What Incline is there between X-Ray Source and Image Receptor?
8º
Where would you find a Ghost Image
structure lying outside the focal trough
What 4 Types of Ghost Images can you get and why?
larger image - due to beam divergence
higher image - due to upward angle
opposite side of the image
blurred - more vertical then horizontal
What is the Effect of Chin Down?
out of focus lower incisors
distorted occlusal plane
= smiley face
What is the Effect of Chin up?
out of focus upper incisors
inverted occlusal place
= grumpy face
What is the Effect of Being too close to the Xray Source?
more divergence = teeth appear larger
- out of focus anterior teeth
- excessive cervical spine
What is the Effect of being Too Far From the X-Ray Source?
- teeth are magnified
- out of focus anterior teeth
What is the Effect of Being Too Rotated?
one side is enlarged more than the other, the side that is further away appears blurry and enlarged, the side that is close appears sharper and smaller
4 Pros of Panoramic Radiography
- shows entire dentition
- time efficient
- radiation dose may be lower than full mouth of intra-oral images
- tolerable by patients
7 Cons of Panoramic Radiography
- only focal trough features are in focus
- teeth can overlap
- careful positioning required
- superimposition = misinterpretation
- image can be distorted
- resolution not as good
- long exposure
