Panoramic radiography and anatomy Flashcards
what’s panoramic radiography?
extra-oral imaging technique used to show a wide view of the upper and lower jaws on a single projection
in panoramic x-ray the tube head rotates around the patient’s head in one direction while the receptor rotates in the opposite direction
The movement of the
receptor and the tubehead
produces an image through
the process known as
tomography
Define tomography?
an imaging technique that allows the imaging of one layer or section of the body while blurring images from
structures in other planes
What is the rotational
center
The pivotal point, or
axis, around which
the cassette carrier
and x-ray tubehead
rotate
Define focal trough?
invisible area that is located in the space between the source of radiation and the image receptor
why is the concept of focal trough important?
because many of the errors in technique are caused by improper patient positioning
what are the types of resultant images
1-real image
2-double image
3-ghost image
Define real image?
Results when a structure lies between the receptor and moving rotation
center
Define double image ?
Results when an anatomic structure that is located behind the moving rotation
center is penetrated twice by the x-ray beam
Define ghost image?
Results when an anatomic structure or object is located outside of the focal
plane and close to the x-ray source
Advantages of panorama?
1-Field size (large)
2-simplicity
3-patient cooperation
4-minimal exposure
Disadvantages of panorama?
1-image quality
2-focal trough limitations
3-distortion
4-equipment cost
Common errors in panorama, during patient preparation
-foregin objects (like earpods, eyeglasses, earrings)
Common errors in panorama, during patient positioning
1-improper tongue position (results in radiolucent shadows obscures the apices of maxillary teeth)
2-head tilted downward
3-head tilted upward
4-patient movement
