Dental panoramic radiography Flashcards
what is a tomogram recap
Radiograph showing a slice or section of tissue in focus
Tissues on either side of the slice are not clearly seen
Tissues seen are within the focal trough
Multiple tomographs can make a 3D image e.g. CT
how does dental panoramic tomography (DPT) work?
X-ray source ? patient
Receptor ? patient
Both rotate in ? directions at the same time ?* (they remain ? each other)
Structures in the focal slice remain projected on the same point on the receptor and appear ?
Structures outside the focal slice are continually projected on different parts of the receptor and appear ?
The focal trough corresponds to shape of ?
behind
in front of
opposite
180*
opposite
clearly
blurry
dental arch
what type of image receptor does DPT use?
indirect action film
digital - phosphor plates or solid state sensors
how does indirect action film work?
Cassette contains intensifying screens that produce light from x-rays
receptor sensitive to light
compare the image quality of direct and indirect action film
indirect action film not as good as direct action film as light affects larger area than a photon
3 clinical indications for DPT
Lesions not completely visible on intraoral
Gross dental disease/neglect
Symptomatic third molars
disadvantages of DPT
4
Lack of fine details
Superimposition of other soft and hard tissues, air shadows
Requires cooperation -> correct position for long time 16s
Magnification of image due to
object/receptor distance
remember patient positioning for DPT
Remove metal foreign bodies from head and neck e.g. jewellery
Patient stands with spine straight holding handles
Bites on bite block edge to edge
Light beam markers
Tongue to roof of mouth
Stand still
is a lead apron required for DPT?
no
look at the uk background radiation
what is used to get field size limitation?
collimator
DPT projections
the left side image is what kind of projection?
lateral projection of the right side of the mandible and spine
DPT projections
The central portion is what kind ot projection?
posteroanterior projection
X-ray tube behind patient and sensor in front
DPT projections
The right side of the image is what kind of projection?
lateral projection of the left side of the mandible and spine
