CHAPTER 22: PANORAMIC IMAGING Flashcards
shows a wide view of the maxilla and the mandible and surrounding structures
PANORAMIC IMAGE
allows for the visualization of the patient’s oral and facial structures spread out across a flat surface.
PANORAMIC IMAGING
What kind of technique is panoramic imaging and what does it examine
extra oral technique
examines maxilla and mandible on a single projection .
The panoramic image is typically used for the following purposes:
evaluate dentition and supporting structures
evaluate impacted teeth
detect diseases and lesions of the jaw
evaluate trauma
a panoramic image can be used to detect caries. TRUE OR FALSE
FALSE
an imaging technique that allows the imaging of one layer, or section, of the body while blurring the images of structures in other planes.
tomography
The pivotal point, or axis, around which the receptor and the x-ray tubehead rotate is termed the
rotation center
a three-dimensional curved zone in which structures are clearly demonstrated on a panoramic image.
focal trough
this image results when a structure lies between the receptor and moving rotation center. this image is a “true” image; it appears in the correct anatomic location with varying degrees of sharpness and distortion.
real image
results when an anatomic structure that is located behind the moving rotation center is penetrated twice by the x-ray beam. this image has the same proportions as the real image and is located in the same location on the opposite side of the receptor.this image appears as a mirror image, or the reverse of the real image.
double image
This image results when an anatomic structure or object is located outside of the focal plane and close to the x-ray source. This image resembles its true image and is found on the opposite side of the receptor; it appears blurred, magnified, and higher than the actual counterpart
ghost image
The main components of the panoramic unit, whether digital or film-based, include the following
xray tubehead
head positioner
exposure controls
The function of the collimator
restrict size and shape of xray beam
the tubehead of the panoramic unit always rotates _____ the patient’s head, while the receptor rotates in ________ of the patient.
behind
in front
consists of a chin rest, notched bite-block, forehead rest, and lateral head supports or guides
head positioner
In panoramic x-ray units, the image receptor may be a :
direct digital sensor
(CCD or CMOS),
a PSP plate,
or film.
used in film-based panoramic imaging; this film is sensitive to the light emitted from intensifying screens
extra oral screen films
where is a screen film placed
between t wo intersifying screens in a cassette holder.
Two basic types of intensifying screens are used:
calcium tungstate
rare earth
which screen requires less xray exposure
rare earth screens
is a device that is used to hold the extraoral film and intensifying screens
casette
an imaginary plane that passes through the top of the ear canal and the bottom of the eye socketbparallel to the floor
frankfort plane
The panoramic image may be divided into six areas for review:
dentition
ramus & cervical spine
nasal cavity & maxillary sinus
body of the mandible
condoyle
hyoid
It is important to note that with digital imaging, an overexposed image can be corrected with the use of software, but an underexposed image cannot. T OR F
TRUE
The two most common patient preparation errors :
ghost image
lead apron artifact
a radiopaque artifact seen on a panoramic image, is produced when a thick, dense object is located outside of the focal plane and close to the x-ray source
ghost image
causes of ghost images
metal jewelry, glasses, necklaces
or normal anatomic landmarks (ramus of mandible, hard palate)
If a lead apron with a thyroid collar is used during the exposure of a panoramic projection, a bilateral radiopaque artifact results that obstructs the mandible.
list the solution
lead apron artifcact
solution: use lead apron WITHOUT a thyroid collar.
ghost image
