Extra Oral Radiography Flashcards Preview

Radiography > Extra Oral Radiography > Flashcards

Flashcards in Extra Oral Radiography Deck (25)
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1
Q

Name extra oral views of cranium and maxilla

A

Lateral cephalogram
Lateral skull
Occipito mental view
TM joint views

2
Q

From what direction does the X-ray beam come for a posters anterior views?

A

From back to film placed at front

3
Q

From what direction does the X-ray beam come for a antero posterior view?

A

X-ray beam from front to film placed at back

4
Q

From what direction does the X-ray beam come for a lateral view?

A

From side

5
Q

Describe the radiographic baseline

A

Outer canthus of eye to external auditory meatus

6
Q

What does the radiographic baseline represents?

A

Base of skull

7
Q

Describe the Frankfort plane

A

Inferior orbital border to upper border of external auditory meatus

8
Q

What does the Frankfort plane represent?

A

Anthropological base line

9
Q

Describe the maxillary occlusal plane?

A

ALA of nose to Tragus of ear

10
Q

What equipment if required for extra oral radiography?

A
Skull unit
Cephalometric unit
High intensity, high penetrating beam 
Cassette with intensifying screen and film 
Anti scatter grid
11
Q

What is Compton scatter?

A

When X-rays pass through tissues and some are scattered

12
Q

Why is more scattered produced in skull radiography?

A

Field of the beam is increase therefore more scatter is produced

13
Q

What does scatter radiation add to?

A

Background fog= greyer image

14
Q

What is the purpose of anti scatter grid?

A

Stops scattered photons reaching film

15
Q

What is the composition of anti scatter grids?

A

Narrow strips of lead alternating with plastic

16
Q

When is a postero anterior film indicated?

A

Fractures
Cysts and malignancy
Visualisation of posterior body of mandible
Midline can be obscured by spine

17
Q

Benefits of postero anterior?

A

Reduced magnification of facial structures

Reduced dose to eyes

18
Q

When would a reverse Townes be indicated?

A

Trauma or pathology

Improve visualisation of head and neck of condyle

19
Q

Describe positioning re. Reverse Townes

A

Positioned re. PA
X-ray beam angled 30 degrees up
Centred through midline

20
Q

When would a lateral oblique radiograph be indicated?

A

Fracture
Pathology of cysts
Assessment of 8s
Specials needs and children who can tolerate bws re. Diagnosis of caries

21
Q

What are the 3 techniques re. Lateral oblique X-rays?

A

Isocentric
Dental tube vertical
Dental tube horizontal

22
Q

When is cephalometric radiography indicated?

A

Ortho assessment

Pre ortho surgery

23
Q

What appears on image re. Cephalometric?

A

Soft and hard tissue

24
Q

What is the function of the aluminium filter?

A

Allows visualisation of bone and soft tissue on one film

25
Q

Name 4 extra oral views of the mandible

A

Postero anterior
Reverse tommes
Lateral oblique mandible
DPT