radiology Flashcards
4 ways to increase sharpness
decrease focal spot size
increase target-teeth distance
decrease teeth-film distance
little patient movement
2 ways to decrease magnifiation
increase target-teeth distance
decrease teeth-film distance
how should film be angled to tooth
parallel to long axis of tooth
what angle should beam be to tooth
90degrees
bisected angle technqiue
film placed as close to tooth
angle mentally bisected
beam pointed at 90 degrees to this angle
2 methods for PA
paralleling
bisected angle
how would high Kv effect image
darker
what is kv a measurement of
penetrating power of beam
standard Kv
70
disadvantage of lower kv
adds skin dose
but image would be better contrast
how is scatter minimised
collimators
what is the controlled area
1.5m
what is the focal trough
position where image is sharp in DPT
what is Sv
biological damage caused by xrays
how is head positioned for smiley DPT
head down
if front teeth blurred + wide what has gone wrong in DPT
pt too far back
where will ghost image (i.e. earring) appear on film
opposite side
at what age would you first take DPT
6years
difference between IRR and IRMER
IRR protects staff
IRMER protects pt
3 main areas of IRMER regulation
justification
optimisation
limitation
who is IRMER referrer
individual who refers pt for radiation i.e. dentist
who is IR(ME)R practitioner
individual responsible for justifying radiation e.g. dentist
who is IRMER operator
any person who carries out radiograph
how to optimise radiation
as low as reasonably possible = fastest speed
how to limit radiation
no exposure to excess predetermined limit
job of radiation protection supervisor
1 RPS to 20-30members of staff
ensure staff follow local rules
what has happened in image too dark
over exposed or over processed
