radiology 2

Question 1

When assessing radio graphs what is involved in step 1 - the overview

Answer 1

is it suitable
is it diagnostically acceptable
any technique errors e.g positioning, tilting, excessive contrast
any foreign bodies, movement artefacts?
are the proportions normal ?

Question 2

When assessing radio graphs what is involved in step 2 - assessing teeth

Answer 2

number, position , development, caries, restoration , resorption, roots, developing teeth

Question 3

When assessing radio graphs what is involved in step 3 - apical tissues

Answer 3

lamina dura - intact / lost?
periodontal ligament space - normal/ widened ?
abnormal radiolucencies/ radiopacities at apices

Question 4

When assessing radio graphs what is involved in step 4 - periodontal tissues

Answer 4

bone levels/ calculus deposits/ furcation involvement

Question 5

When assessing radio graphs what is involved in step 5 - bone

Answer 5

bone levels, shape/size/symmetry, bones other than mandible and alveolar
abnormal radiolucencies/ pacities

Question 6

What are the 5 stages of assessing a radiograph

Answer 6

overview
teeth
apical tissues
periodontal tissues
bone

Question 7

if assessing specific structures/ pathologies on a radiograph what should be described

Answer 7

site - crown/ alveolar bone/ roots
radiodensity - paque/lucent/ combo
shape - round/ irregular/ scalloped
margins - corticated/ well defined/ irregular
size - 10 x5mm/ spanning 13 to 23
multiplicity - few/ solitary/ many

Question 8

how often should bitewings be taken for high risk caries patients

Answer 8

every 6 months

Question 9

how often should bitewings be taken for moderate caries risk caries patients

Answer 9

annually

Question 10

how often should bitewings be taken for low caries risk patients with a primary dentition

Answer 10

every 12-18 months

Question 11

how often should bitewings be taken for a low caries risk patient with a permanent dentition

Answer 11

every 2 years

Question 12

what type of radiation are x rays

Answer 12

electromagnetic radiation

Question 13

why are x rays a risk to humans

Answer 13

they can cause ionisation which is the displacement of electrons from atoms/molecules

Question 14

what 3 things are contained within the tubehead of an x ray

Answer 14

cathode (+ve)
transformer
anode (-ve)

Question 15

function of the cathode in x ray tubehead

Answer 15

compromised of filament (coiled metal wire that when heated releases electrons) and a focusing cup (metal plate around filament that repels released electrons from filament towards anode)

Question 16

purpose of transformers in x ray tubehead

Answer 16

change the mains electrical supply to the machines required voltage

Question 17

purpose of anode in x ray tubehead

Answer 17

compromised of target (metal block (tungsten) that is bombarded with electrons released from cathode filament) (contains focal spot where electrons hit) and a heat discipating block (ensures machine doesn’t overheat by absorbing heat produced - usually copper)

Question 18

penumbra effect

Answer 18

blurring of radiographic image due to focal spot being a small area rather than a single point
ideally focal spot should be as small as possible

Question 19

what are the benefits of having an angled focal spot within the x ray tubehead

Answer 19

larger impact area therefore decreased heat production whilst still achieving an x ray beam with a small area therefore reducing the penumbra effect
(diagram in notes)

Question 20

purpose of the glass envelope within an x ray tubehead

Answer 20

made of leaded glass and surrounds cathode and anode so that photons can escape except for one small window where they escape and form the x ray beam
contains vaccum to ensure no air molecules within the space

Question 21

filtration

Answer 21

done using a thin sheet of aluminium placed over the path of the x ray beam
this removes low energy x ray photons which would not contribute to image quality but would increase the patient dose

Question 22

collimator

Answer 22

lead diaphragm attached to the end of spacer cone which crops beam to the shape and size of the receptor therefore ensuring minimal patient dose

Question 23

where is the fsd measured from

Answer 23

focus to skin distance
measured from focal spot NOT where x ray beam exits tube head
for modern equipment usually 200mm

Question 24

what is the x ray anode made of (target/focal spot)

Answer 24

tungsten