Radiology techniques 2

Question 1

x ray tube angled too far down and pointed up what happens to image?

Answer 1

image elongated

Question 2

xray tube angled too far up and pointing down what happens to image?

Answer 2

image foreshortened

Question 3

why take bitewings?

Answer 3

detect caries
monitor carious lesions
asses current restorations
assess periodontal status

Question 4

horizontal vs vertical?

Answer 4

horizontal - 1 image vertical - 2 each side
distal of 4 to mesial of 8 premolars and molars
crowns and 1/3 of roots more of roots

Question 5

positioning for bitewings?

Answer 5

film and object parallel
film close to object
xray perpendicular to object and film

Question 6

holder types? rigid plastic?

Answer 6

holds film accurately
assists x ray tube positioning
uncomfortable

Question 7

holder types? paper tab?

Answer 7

comfortable
xray tube positioned by eye
inaccurate positioning

Question 8

horizontal overlap?

Answer 8

difficult to avoid
crowding/tilting of teeth
acceptable if less than have of enamel superimposed
easy to miss carious lesions
must show EDJ and dentinal half of enamel

Question 9

how to reduce magnification?

Answer 9

reduce distance between the film and the tooth

Question 10

what angle should the xray beam be to the tooth/film?

Answer 10

at right angles to tooth/film

Question 11

what seperates the cusps?

Answer 11

vertical angulation

Question 12

where should the dot point towards on a bitewing?

Answer 12

towards the palate

Question 13

by using the rectangular collimator how much is the patient dose reduced by?

Answer 13

50%